Fatigue Responses in Various Muscle Groups in Well-Trained Competitive Male Players after a Simulated Soccer Game

PubMed Central

Fransson, Dan; Vigh-Larsen, Jeppe Foged; Fatouros, Ioannis G.; Krustrup, Peter; Mohr, Magni

2018-01-01

Abstract We examined the degree of post-game fatigue and the recovery pattern in various leg and upper-body muscle groups after a simulated soccer game. Well-trained competitive male soccer players (n = 12) participated in the study. The players completed the Copenhagen Soccer Test, a 2 x 45 min simulated soccer protocol, following baseline measures of maximal voluntary contractions of multiple muscle groups and systemic markers of muscle damage and inflammation at 0, 24 and 48 h into recovery. All muscle groups had a strength decrement (p ≤ 0.05) at 0 h post-match with knee flexors (14 ± 3%) and hip abductors (6 ± 1%) demonstrating the largest and smallest impairment. However, 24 h into recovery all individual muscles had recovered. When pooled in specific muscle groups, the trunk muscles and knee joint muscles presented the largest decline 0 h post-match, 11 ± 2% for both, with the performance decrement still persistent (4 ± 1%, p ≤ 0.05) for trunk muscles 24 h into recovery. Large inter-player variations were observed in game-induced fatigue and recovery patterns in the various muscle groups. Markers of muscle damage and inflammation peaked 0 h post-match (myoglobin) and 24 h into recovery (creatine kinase), respectively, but thereafter returned to baseline. Intermittent test performance correlated with creatine kinase activity 24 h after the Copenhagen Soccer Test (r = -0.70; p = 0.02). In conclusion, post-game fatigue is evident in multiple muscle groups with knee flexors showing the greatest performance decrement. Fatigue and recovery patterns vary markedly between muscle groups and players, yet trunk muscles display the slowest recovery. PMID:29599862

Fatigue Responses in Various Muscle Groups in Well-Trained Competitive Male Players after a Simulated Soccer Game.

PubMed

Fransson, Dan; Vigh-Larsen, Jeppe Foged; Fatouros, Ioannis G; Krustrup, Peter; Mohr, Magni

2018-03-01

We examined the degree of post-game fatigue and the recovery pattern in various leg and upper-body muscle groups after a simulated soccer game. Well-trained competitive male soccer players (n = 12) participated in the study. The players completed the Copenhagen Soccer Test, a 2 x 45 min simulated soccer protocol, following baseline measures of maximal voluntary contractions of multiple muscle groups and systemic markers of muscle damage and inflammation at 0, 24 and 48 h into recovery. All muscle groups had a strength decrement ( p ≤ 0.05) at 0 h post-match with knee flexors (14 ± 3%) and hip abductors (6 ± 1%) demonstrating the largest and smallest impairment. However, 24 h into recovery all individual muscles had recovered. When pooled in specific muscle groups, the trunk muscles and knee joint muscles presented the largest decline 0 h post-match, 11 ± 2% for both, with the performance decrement still persistent (4 ± 1%, p ≤ 0.05) for trunk muscles 24 h into recovery. Large inter-player variations were observed in game-induced fatigue and recovery patterns in the various muscle groups. Markers of muscle damage and inflammation peaked 0 h post-match (myoglobin) and 24 h into recovery (creatine kinase), respectively, but thereafter returned to baseline. Intermittent test performance correlated with creatine kinase activity 24 h after the Copenhagen Soccer Test (r = -0.70; p = 0.02). In conclusion, post-game fatigue is evident in multiple muscle groups with knee flexors showing the greatest performance decrement. Fatigue and recovery patterns vary markedly between muscle groups and players, yet trunk muscles display the slowest recovery.

The effect of obesity on the contractile performance of isolated mouse soleus, EDL, and diaphragm muscles.

PubMed

Tallis, Jason; Hill, Cameron; James, Rob S; Cox, Val M; Seebacher, Frank

2017-01-01

Obesity affects the major metabolic and cellular processes involved in skeletal muscle contractility. Surprisingly, the effect of obesity on isolated skeletal muscle performance remains unresolved. The present study is the first to examine the muscle-specific changes in contractility following dietary-induced obesity using an isolated muscle work-loop (WL) model that more closely represents in vivo muscle performance. Following 16-wk high-calorific feeding, soleus (SOL), extensor digitorum longus (EDL), and diaphragm (DIA) were isolated from female (CD-1) mice, and contractile performance was compared against a lean control group. Obese SOL produced greater isometric force; however, isometric stress (force per unit muscle area), absolute WL power, and normalized WL power (watts per kilogram muscle mass) were unaffected. Maximal isometric force and absolute WL power of the EDL were similar between groups. For both EDL and DIA, isometric stress and normalized WL power were reduced in the obese groups. Obesity caused a significant reduction in fatigue resistance in all cases. Our findings demonstrate a muscle-specific reduction in contractile performance and muscle quality that is likely related to in vivo mechanical role, fiber type, and metabolic profile, which may in part be related to changes in myosin heavy chain expression and AMP-activated protein kinase activity. These results infer that, beyond the additional requirement of moving a larger body mass, functional performance and quality of life may be further limited by poor muscle function in obese individuals. As such, a reduction in muscle performance may be a substantial contributor to the negative cycle of obesity. The effect of obesity on isolated muscle function is surprisingly underresearched. The present study is the first to examine the effects of obesity on isolated muscle performance using a method that more closely represents real-world muscle function. This work uniquely establishes a muscle-specific profile of mechanical changes in relation to underpinning mechanisms. These findings may be important to understanding the negative cycle of obesity and in designing interventions for improving weight status. Copyright © 2017 the American Physiological Society.

Muscle MRI findings in facioscapulohumeral muscular dystrophy.

PubMed

Gerevini, Simonetta; Scarlato, Marina; Maggi, Lorenzo; Cava, Mariangela; Caliendo, Giandomenico; Pasanisi, Barbara; Falini, Andrea; Previtali, Stefano Carlo; Morandi, Lucia

2016-03-01

Facioscapulohumeral muscular dystrophy (FSHD) is characterized by extremely variable degrees of facial, scapular and lower limb muscle involvement. Clinical and genetic determination can be difficult, as molecular analysis is not always definitive, and other similar muscle disorders may have overlapping clinical manifestations. Whole-body muscle MRI examination for fat infiltration, atrophy and oedema was performed to identify specific patterns of muscle involvement in FSHD patients (30 subjects), and compared to a group of control patients (23) affected by other myopathies (NFSHD). In FSHD patients, we detected a specific pattern of muscle fatty replacement and atrophy, particularly in upper girdle muscles. The most frequently affected muscles, including paucisymptomatic and severely affected FSHD patients, were trapezius, teres major and serratus anterior. Moreover, asymmetric muscle involvement was significantly higher in FSHD as compared to NFSHD patients. In conclusion, muscle MRI is very sensitive for identifying a specific pattern of involvement in FSHD patients and in detecting selective muscle involvement of non-clinically testable muscles. Muscle MRI constitutes a reliable tool for differentiating FSHD from other muscular dystrophies to direct diagnostic molecular analysis, as well as to investigate FSHD natural history and follow-up of the disease. Muscle MRI identifies a specific pattern of muscle involvement in FSHD patients. Muscle MRI may predict FSHD in asymptomatic and severely affected patients. Muscle MRI of upper girdle better predicts FSHD. Muscle MRI may differentiate FSHD from other forms of muscular dystrophy. Muscle MRI may show the involvement of non-clinical testable muscles.

Influence of exercise contraction mode and protein supplementation on human skeletal muscle satellite cell content and muscle fiber growth.

PubMed

Farup, Jean; Rahbek, Stine Klejs; Riis, Simon; Vendelbo, Mikkel Holm; Paoli, Frank de; Vissing, Kristian

2014-10-15

Skeletal muscle satellite cells (SCs) are involved in remodeling and hypertrophy processes of skeletal muscle. However, little knowledge exists on extrinsic factors that influence the content of SCs in skeletal muscle. In a comparative human study, we investigated the muscle fiber type-specific association between emergence of satellite cells (SCs), muscle growth, and remodeling in response to 12 wk unilateral resistance training performed as eccentric (Ecc) or concentric (Conc) resistance training ± whey protein (Whey, 19.5 g protein + 19.5 g glucose) or placebo (Placebo, 39 g glucose) supplementation. Muscle biopsies (vastus lateralis) were analyzed for fiber type-specific SCs, myonuclei, and fiber cross-sectional area (CSA). Following training, SCs increased with Conc in both type I and type II fibers (P < 0.01) and exhibited a group difference from Ecc (P < 0.05), which did not increase. Myonuclei content in type I fibers increased in all groups (P < 0.01), while a specific accretion of myonuclei in type II fibers was observed in the Whey-Conc (P < 0.01) and Placebo-Ecc (P < 0.01) groups. Similarly, whereas type I fiber CSA increased independently of intervention (P < 0.001), type II fiber CSA increased exclusively with Whey-Conc (P < 0.01) and type II fiber hypertrophy correlated with whole muscle hypertrophy exclusively following Conc training (P < 0.01). In conclusion, isolated concentric knee extensor resistance training appears to constitute a stronger driver of SC content than eccentric resistance training while type II fiber hypertrophy was accentuated when combining concentric resistance training with whey protein supplementation. Copyright © 2014 the American Physiological Society.

A comparison of hemisphere-specific training pattern in Inter-limb Learning Transfer (ILT) for stroke patients with hemiparesis.

PubMed

Yoo, In-gyu; Jung, Min-ye; Yoo, Eun-young; Park, Ji-hyuk; Kang, Dae-hyuk; Lee, Jin

2014-01-01

Stroke patients have major problems with impaired upper-extremity function. Unfortunately, many patients do not experience a full recovery from movement deficits in the upper extremities. The purpose of this study was to compare the effectiveness of inter-limb learning transfer (ILT) to the contralateral upper limb after both hemisphere-specific and -unspecific ipsilateral upper limb training for stroke patients with hemiparesis. Twenty-four stroke patients with hemiparesis participated. The hemisphere-specific training group performed reaching movements in a customized training setting in which non-dominant limb training participants began from a single starting location and proceeded to one of three target locations (1S3T condition); the dominant limb training participants started from one of three starting locations and proceeded to a single target location (3S1T condition). The hemisphere-unspecific training group performed these movements starting under reverse-start and target conditions. The non-dominant to dominant limb transfer, the hemisphere-specific training group performance time decreased significantly as compared with the pre-training session (p < 0.05). Also, the isolation contraction ratio was decreased significantly from that of the pre-training session in the biceps brachii muscles and increased significantly in the upper trapezius muscles (p < 0.05). And, dominant to non-dominant limb transfer in the hemisphere-specific training group significantly increased RMS amplitudes from the pre-training session in the biceps brachii and triceps muscles (p < 0.05). Also, the isolation contraction ratio was increased significantly from that of the pre-training session in the biceps brachii muscles and decreased significantly in the upper trapezius muscles (p < 0.05). However, the hemisphere-unspecific training group showed no significant differences in inter-limb learning transfer (ILT). The transfer of hemisphere-specific training from one arm to the other had a more positive influence on functional recovery than did hemisphere-unspecific training for patients with stroke and hemiparesis.

Muscle-strengthening and aerobic activities and mortality among 3+ year cancer survivors in the U.S.

PubMed

Tarasenko, Yelena N; Linder, Daniel F; Miller, Eric A

2018-05-01

This study examined the association between adherence to American College of Sports Medicine and American Cancer Society guidelines on aerobic and muscle-strengthening activities and mortality risks among 3+ year cancer survivors in the U.S. The observational study was based on 1999-2009 National Health Interview Survey Linked Mortality Files with follow-up through 2011. After applying exclusion criteria, there were 13,997 observations. The hazard ratios (HRs) for meeting recommendations on muscle-strengthening activities only, on aerobic activities only, and on both types of physical activity (i.e., adhering to complete guidelines) were calculated using a reference group of cancer survivors engaging in neither. Unadjusted and adjusted HRs of all-cause, cancer-specific, and cardiovascular disease-specific mortalities were estimated using Cox proportional hazards models. In all models, compared to the reference group, cancer survivors adhering to complete guidelines had significantly decreased all-cause, cancer-specific, and cardiovascular disease-specific mortalities (HRs ranged from 0.37 to 0.64, p's < 0.05). There were no statistically significant differences between hazard rates of cancer survivors engaging in recommended levels of muscle-strengthening activities only and the reference group (HRs ranged from 0.76 to 0.94, p's > 0.05). Wald test statistics suggested a significant dose-response relationship between levels of adherence to complete guidelines and cancer-specific mortality. While muscle-strengthening activities by themselves do not appear to reduce mortality risks, such activities may provide added cancer-specific survival benefits to 3+ year cancer survivors who are already aerobically active.

[Focal myositis: An unknown disease].

PubMed

Gallay, L; Streichenberger, N; Benveniste, O; Allenbach, Y

2017-10-01

Focal myositis are inflammatory muscle diseases of unknown origin. At the opposite from the other idiopathic inflammatory myopathies, they are restricted to a single muscle or to a muscle group. They are not associated with extramuscular manifestations, and they have a good prognosis without any treatment. They are characterized by a localized swelling affecting mostly lower limbs. The pseudo-tumor can be painful, but is not associated with a muscle weakness. Creatine kinase level is normal. Muscle MRI shows an inflammation restricted to a muscle or a muscle group. Muscle biopsy and pathological analysis remain necessary for the diagnosis, showing inflammatory infiltrates composed by macrophages and lymphocytes without any specific distribution within the muscle. Focal overexpression of HLA-1 by the muscle fibers is frequently observed. The muscle biopsy permits to rule out differential diagnosis such a malignancy (sarcoma). Spontaneous remission occurs within weeks or months after the first symptoms, relapse is unusual. Copyright © 2017. Published by Elsevier SAS.

Ultrasound-Based Detection of Low Muscle Mass for Diagnosis of Sarcopenia in Older Adults.

PubMed

Minetto, Marco A; Caresio, Cristina; Menapace, Tommaso; Hajdarevic, Arnel; Marchini, Andrea; Molinari, Filippo; Maffiuletti, Nicola A

2016-05-01

To establish muscle-specific cut-off values for ultrasound-based detection of low muscle mass, and to assess its prevalence in a population of frail older subjects when applying the cut-points of different muscles and those of different sarcopenic indices. Cross-sectional study. Geriatric outpatient clinic and clinical research laboratory. A total of 44 older adults (30 women and 14 men, mean age 82 years, range 67-93 years) and 60 younger individuals (30 women and 30 men, mean age 26 years, range 20-36 years) participated. Body composition and thickness of 4 lower limb muscles (rectus femoris, vastus lateralis, tibialis anterior, medial gastrocnemius) were respectively assessed by bioelectrical impedance analysis (BIA) and ultrasonography. Site-specific cut-points for ultrasound-based assessment of low muscle mass (muscle thickness values 2 standard deviations below the gender-specific means of our sample of younger subjects) and comparative prevalence rates of low muscle mass. The following site-specific cut-points for muscle thickness were identified: rectus femoris: 20 mm in men and 16 mm in women; vastus lateralis: 17 mm in men and 15 mm in women; tibialis anterior: 23 mm in men and 22 mm in women; and medial gastrocnemius: 13 mm in both men and women. The prevalence of low muscle mass in older adults was highly dependent on the muscle being investigated; it varied from 86% for thigh muscles to 30% for leg muscles. Moreover, the prevalence of low muscle mass was highly dependent on the applied diagnostic criterion and on the adopted cut-off value; it ranged from 2% to 75% for different BIA-derived criteria. We suggest that muscle ultrasonography provides physiatrists with a practical and accurate tool for identifying individuals with low muscle mass. However, the usability of cut-off values established in our group of healthy younger subjects of white ethnicity to identify low muscle mass in older individuals of different ethnic groups remains to be demonstrated in future studies. Copyright © 2016 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Subjective evaluation of physical and mental workload interactions across different muscle groups.

PubMed

Mehta, Ranjana K; Agnew, Michael J

2015-01-01

Both physical and mental demands, and their interactions, have been shown to increase biomechanical loading and physiological reactivity as well as impair task performance. Because these interactions have shown to be muscle-dependent, the aim of this study was to determine the sensitivity of the NASA Task Load Index (NASA TLX) and Ratings of Perceived Exertion (RPE) to evaluate physical and mental workload during muscle-specific tasks. Twenty-four participants performed upper extremity and low back exertions at three physical workload levels in the absence and presence of a mental stressor. Outcome measures included RPE and NASA TLX (six sub-scales) ratings. The findings indicate that while both RPEs and NASA TLX ratings were sensitive to muscle-specific changes in physical demand, only an additional mental stressor and its interaction with either physical demand or muscle groups influenced the effort sub-scale and overall workload scores of the NASA TLX. While additional investigations in actual work settings are warranted, the NASA TLX shows promise in evaluating perceived workload that is sensitive not only to physical and mental demands but also sensitive in determining workload for tasks that employ different muscle groups.

Smooth muscle tumors of soft tissue and non-uterine viscera: biology and prognosis.

PubMed

Miettinen, Markku

2014-01-01

Smooth muscle tumors are here considered an essentially dichotomous group composed of benign leiomyomas and malignant leiomyosarcomas. Soft tissue smooth muscle tumors with both atypia and mitotic activity are generally diagnosed leiomyosarcomas acknowledging potential for metastasis. However, lesions exist that cannot be comfortably placed in either category, and in such cases the designation 'smooth muscle tumor of uncertain biologic potential' is appropriate. The use of this category is often necessary with limited sampling, such as needle core biopsies. Benign smooth muscle tumors include smooth muscle hamartoma and angioleiomyoma. A specific category of leiomyomas are estrogen-receptor positive ones in women. These are similar to uterine leiomyomas and can occur anywhere in the abdomen and abdominal wall. Leiomyosarcomas can occur at any site, although are more frequent in the retroperitoneum and proximal extremities. They are recognized by likeness to smooth muscle cells but can undergo pleomorphic evolution ('dedifferentiation'). Presence of smooth muscle actin is nearly uniform and desmin-positivity usual. This and the lack of KIT expression separate leiomyosarcoma from GIST, an important problem in abdominal soft tissues. EBV-associated smooth muscle tumors are a specific subcategory occurring in AIDS or post-transplant patients. These tumors can have incomplete smooth muscle differentiation but show nuclear EBER as a diagnostic feature. In contrast to many other soft tissue tumors, genetics of smooth muscle tumors are poorly understood and such diagnostic testing is not yet generally applicable in this histogenetic group. Leiomyosarcomas are known to be genetically complex, often showing 'chaotic' karyotypes including aneuploidy or polyploidy, and no recurrent tumor-specific translocations have been detected.

Muscle Dysmorphia and the Perception of Men's Peer Muscularity Preferences.

PubMed

Lin, Linda; DeCusati, Frank

2016-11-01

Research suggests that peer muscularity norms preferences are related to men's body image, but little information is known about how perceptions of specific peer group norms preferences are related to men's body image disturbances and specific health behaviors. This study investigated how men perceived the muscularity preferences of male, female, close, and distant peers and whether the perceptions of specific peer preferences were related to muscle dysmorphia and steroid use. Data on muscle dysmorphia and the perceptions of peer muscularity norms were collected from 117 male college students. Results indicated that men perceived distant and male peers as having the most exaggerated preferences for muscularity and that those perceptions were not an accurate reflection of their distant male peers' reported preferences. Results also indicated that perceptions of close female peer muscularity preferences were predictive of symptoms of muscle dysmorphia, but this relationship did not exist for other peer groups, suggesting that the perceptions of close female peer preferences may play a role in the development of muscle dysmorphia. No relationship was found between perceptions of peer muscularity preferences and steroid use. © The Author(s) 2015.

Effects of AICAR and exercise on insulin-stimulated glucose uptake, signaling, and GLUT-4 content in rat muscles.

PubMed

Jessen, Niels; Pold, Rasmus; Buhl, Esben S; Jensen, Lasse S; Schmitz, Ole; Lund, Sten

2003-04-01

Physical activity is known to increase insulin action in skeletal muscle, and data have indicated that 5'-AMP-activated protein kinase (AMPK) is involved in the molecular mechanisms behind this beneficial effect. 5-Aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR) can be used as a pharmacological tool to repetitively activate AMPK, and the objective of this study was to explore whether the increase in insulin-stimulated glucose uptake after either long-term exercise or chronic AICAR administration was followed by fiber-type-specific changes in insulin signaling and/or changes in GLUT-4 expression. Wistar rats were allocated into three groups: an exercise group trained on treadmill for 5 days, an AICAR group exposed to daily subcutaneous injections of AICAR, and a sedentary control group. AMPK activity, insulin-stimulated glucose transport, insulin signaling, and GLUT-4 expression were determined in muscles characterized by different fiber type compositions. Both exercised and AICAR-injected animals displayed a fiber-type-specific increase in glucose transport with the most marked increase in muscles with a high content of type IIb fibers. This increase was accompanied by a concomitant increase in GLUT-4 expression. Insulin signaling as assessed by phosphatidylinositol 3-kinase and PKB/Akt activity was enhanced only after AICAR administration and in a non-fiber-type-specific manner. In conclusion, chronic AICAR administration and long-term exercise both improve insulin-stimulated glucose transport in skeletal muscle in a fiber-type-specific way, and this is associated with an increase in GLUT-4 content.

Protective effect of Naringin on experimental hindlimb ischemia/reperfusion injury in rats.

PubMed

Gürsul, Cebrail; Ekinci Akdemir, Fazile Nur; Akkoyun, Turan; Can, İsmail; Gül, Mustafa; Gülçin, İlhami

2016-01-01

This study was designed to investigate the antioxidant effects of Naringin, in ischemia/reperfusion (I/R)-induced skeletal muscle injury in rats. The rats were randomly allocated into three groups including control, I/R and I/R + Naringin groups. Muscle tissues of I/R groups revealed significantly higher antioxidant enzyme activities, and increased levels of malondialdehyde, as specific a marker of the lipid peroxidation and tissue damage, compared to the control group (p < 0.05). Levels of these parameters in muscle revealed significant reductions in the I/R + Naringin group compared to the I/R group (p < 0.05). Histopathological examination of ischemia muscles in the I/R group showed significant degeneration and inflammation compared to the control group, whereas ischemic muscles of Naringin-administered group showed significant reduction in degeneration and inflammation compared to the I/R group (p < 0.05). We suggest that the protective effect of Naringin may reduce the I/R injury in cases of extremity injuries with acute vascular complications, extremity surgery with prolonged tourniquet application.

Design and testing of regulatory cassettes for optimal activity in skeletal and cardiac muscles.

PubMed

Himeda, Charis L; Chen, Xiaolan; Hauschka, Stephen D

2011-01-01

Gene therapy for muscular dystrophies requires efficient gene delivery to the striated musculature and specific, high-level expression of the therapeutic gene in a physiologically diverse array of muscles. This can be achieved by the use of recombinant adeno-associated virus vectors in conjunction with muscle-specific regulatory cassettes. We have constructed several generations of regulatory cassettes based on the enhancer and promoter of the muscle creatine kinase gene, some of which include heterologous enhancers and individual elements from other muscle genes. Since the relative importance of many control elements varies among different anatomical muscles, we are aiming to tailor these cassettes for high-level expression in cardiac muscle, and in fast and slow skeletal muscles. With the achievement of efficient intravascular gene delivery to isolated limbs, selected muscle groups, and heart in large animal models, the design of cassettes optimized for activity in different muscle types is now a practical goal. In this protocol, we outline the key steps involved in the design of regulatory cassettes for optimal activity in skeletal and cardiac muscle, and testing in mature muscle fiber cultures. The basic principles described here can also be applied to engineering tissue-specific regulatory cassettes for other cell types.

Compensatory strategies during manual wheelchair propulsion in response to weakness in individual muscle groups: A simulation study.

PubMed

Slowik, Jonathan S; McNitt-Gray, Jill L; Requejo, Philip S; Mulroy, Sara J; Neptune, Richard R

2016-03-01

The considerable physical demand placed on the upper extremity during manual wheelchair propulsion is distributed among individual muscles. The strategy used to distribute the workload is likely influenced by the relative force-generating capacities of individual muscles, and some strategies may be associated with a higher injury risk than others. The objective of this study was to use forward dynamics simulations of manual wheelchair propulsion to identify compensatory strategies that can be used to overcome weakness in individual muscle groups and identify specific strategies that may increase injury risk. Identifying these strategies can provide rationale for the design of targeted rehabilitation programs aimed at preventing the development of pain and injury in manual wheelchair users. Muscle-actuated forward dynamics simulations of manual wheelchair propulsion were analyzed to identify compensatory strategies in response to individual muscle group weakness using individual muscle mechanical power and stress as measures of upper extremity demand. The simulation analyses found the upper extremity to be robust to weakness in any single muscle group as the remaining groups were able to compensate and restore normal propulsion mechanics. The rotator cuff muscles experienced relatively high muscle stress levels and exhibited compensatory relationships with the deltoid muscles. These results underline the importance of strengthening the rotator cuff muscles and supporting muscles whose contributions do not increase the potential for impingement (i.e., the thoracohumeral depressors) and minimize the risk of upper extremity injury in manual wheelchair users. Copyright © 2016 Elsevier Ltd. All rights reserved.

Compensatory Strategies during Manual Wheelchair Propulsion in Response to Weakness in Individual Muscle Groups: A Simulation Study

PubMed Central

Slowik, Jonathan S.; McNitt-Gray, Jill L.; Requejo, Philip S.; Mulroy, Sara J.; Neptune, Richard R.

2016-01-01

Background The considerable physical demand placed on the upper extremity during manual wheelchair propulsion is distributed among the individual muscles. The strategy used to distribute the workload is likely influenced by the relative force-generating capacities of individual muscles, and some strategies may be associated with a higher injury risk than others. The objective of this study was to use forward dynamics simulations of manual wheelchair propulsion to identify compensatory strategies that can be used to overcome weakness in individual muscle groups and identify specific strategies that may increase injury risk. Identifying these strategies can provide rationale for the design of targeted rehabilitation programs aimed at preventing the development of pain and injury in manual wheelchair users. Methods Muscle-actuated forward dynamics simulations of manual wheelchair propulsion were analyzed to identify compensatory strategies in response to individual muscle group weakness, using individual muscle mechanical power and stress as measures of upper extremity demand. Findings The simulation analyses found the upper extremity to be robust to weakness in any single muscle group as the remaining groups were able to compensate and restore normal propulsion mechanics. The rotator cuff muscles experienced relatively high muscle stress levels and exhibited compensatory relationships with the deltoid muscles. Interpretation These results underline the importance of strengthening the rotator cuff muscles and supporting muscles whose contributions do not increase the potential for impingement (i.e., the thoracohumeral depressors) and minimize the risk of upper extremity injury in manual wheelchair users. PMID:26945719

Effects of combined stretching and clenbuterol on disuse atrophy in rat soleus muscle.

PubMed

Yamazaki, Toshiaki; Yokogawa, Masami; Tachino, Katsuhiko

2009-01-01

Clinically, disuse muscle atrophy is often seen among patients who are severely debilited and are on prolonged bed rest. Common physical therapy interventions are not successful in preventing disuse muscle atrophy early in the medical treatment of critically ill patients. In situations such as this, the use of a β 2-adrenergic agonist such as clenbuterol (Cb) may be of benefit in preventing atrophy. Also, recent studies have suggested that stretching is possible in preventing disuse muscle atrophy and the decline in muscle strength. The objective of this study was to evaluate the effects of Cb medication combined with stretching (ST) on rat soleus muscle (SOL) during the progression of disuse muscle atrophy. Thirty-five male Wistar rats were used in this study. The rats were divided into five groups: control (CON), hindlimb-unweighting (HU) only, HU+ST, HU+Cb medication, and HU+ST+Cb groups. The right SOL in stretching groups was maintained a stretched position for one hour daily by passively dorsiflexing the ankle joint under non-anesthesia. The experimental period was 2 weeks. In the ST group, peak twitch tension per cross-sectional area in soleus muscle was significantly larger than in the Cb group, while there was no significant difference between the CON and ST groups. The conversion of type I to type II fibers that was observed in the Cb group was not recognized in the combined ST and Cb group. Distinct effect of combined stretching and Cb medication was not recognized statistically. The results indicate that Cb affects muscle morphological characteristics while stretching affects contractile properties. These data suggest that a combined ST and Cb intervention considered the type-specificity of muscle fiber may be need more consideration for preventing disuse muscle atrophy and the decline in muscle strength.

Influence of muscle groups' activation on proximal femoral growth tendency.

PubMed

Yadav, Priti; Shefelbine, Sandra J; Pontén, Eva; Gutierrez-Farewik, Elena M

2017-12-01

Muscle and joint contact force influence stresses at the proximal growth plate of the femur and thus bone growth, affecting the neck shaft angle (NSA) and femoral anteversion (FA). This study aims to illustrate how different muscle groups' activation during gait affects NSA and FA development in able-bodied children. Subject-specific femur models were developed for three able-bodied children (ages 6, 7, and 11 years) using magnetic resonance images. Contributions of different muscle groups-hip flexors, hip extensors, hip adductors, hip abductors, and knee extensors-to overall hip contact force were computed. Specific growth rate for the growth plate was computed, and the growth was simulated in the principal stress direction at each element in the growth front. The predicted growth indicated decreased NSA and FA (of about [Formula: see text] over a four-month period) for able-bodied children. Hip abductors contributed the most, and hip adductors, the least, to growth rate. All muscles groups contributed to a decrease in predicted NSA ([Formula: see text]0.01[Formula: see text]-0.04[Formula: see text] and FA ([Formula: see text]0.004[Formula: see text]-[Formula: see text]), except hip extensors and hip adductors, which showed a tendency to increase the FA ([Formula: see text]0.004[Formula: see text]-[Formula: see text]). Understanding influences of different muscle groups on long bone growth tendency can help in treatment planning for growing children with affected gait.

Carnitine supplementation to obese Zucker rats prevents obesity-induced type II to type I muscle fiber transition and favors an oxidative phenotype of skeletal muscle

PubMed Central

2013-01-01

Background In the present study, we tested the hypothesis that carnitine supplementation counteracts obesity-induced muscle fiber transition from type I to type II. Methods 24 obese Zucker rats were randomly divided into two groups of 12 rats each (obese control, obese carnitine) and 12 lean Zucker rats were selected for lean control group. A control diet was given to both control groups and a carnitine supplemented diet (3 g/kg diet) was given to obese carnitine group for 4 wk. Components of the muscle fiber transformation in skeletal muscle were examined. Results The plasma level of carnitine were lower in the obese control group compared to the lean control group and higher in the obese carnitine group than in the other groups (P < 0.05). Plasma concentrations of triglycerides and non-esterified fatty acids were increased in obese animals compared to lean animals and the obese carnitine group had lower level compared to the obese control group (P < 0.05). The obese carnitine group had an increased number of type I muscle fibers and higher mRNA levels of type I fiber-specific myosin heavy chain, regulators of muscle fiber transition and of genes involved in carnitine uptake, fatty acid transport, β-oxidation, angiogenesis, tricarboxylic acid cycle and thermo genesis in M. rectus femoris compared to the other groups (P < 0.05). Conclusion The results demonstrate that carnitine supplementation to obese Zucker a rat counteracts the obesity-induced muscle fiber transition and restores the muscle oxidative metabolic phenotype. Carnitine supplementation is supposed to be beneficial for the treatment of elevated levels of plasma lipids during obesity or diabetes. PMID:23842456

Muscle focal vibration in healthy subjects: evaluation of the effects on upper limb motor performance measured using a robotic device.

PubMed

Aprile, Irene; Di Sipio, Enrica; Germanotta, Marco; Simbolotti, Chiara; Padua, Luca

2016-04-01

Muscle vibration is a technique that applies a low-amplitude/high-frequency vibratory stimulus to a specific muscle using a mechanical device. The aim of this study was to evaluate, using robot-based outcomes, the effects of focal muscle vibration, at different frequencies, on the motor performance of the upper limb in healthy subjects. Forty-eight volunteer healthy subjects (age: 31 ± 8 years) were enrolled. Subjects were assigned to three different groups: the first group, in which subjects underwent muscle vibration treatment with a frequency of 100 Hz; the second group of subjects underwent the same treatment protocol, but using a frequency of vibration of 200 Hz; finally, the control group did not undergo any treatment. The robot-based evaluation session consisted of visually guided reaching task, performed in the sagittal plane. Our results showed that the vibration treatment improved upper limb motor performance of healthy subjects from the baseline (T0) to 10 days after the end of the treatment (T2), but only the group treated with a frequency of 200 Hz reached statistical significance. Specifically, in this group we found an increase of the number of repetitions (T0: 51.4 ± 22.7; T2: 66.3 ± 11.8), and the smoothness of the movement, as showed by a decrease of the Normalized Jerk (T0: 10.5 ± 2.8; T2: 7.7 ± 0.5). The results of our study support the use of focal muscle vibration protocols in healthy subjects, to improve motor performance.

Muscle tension line concept in nasolabial muscle complex--based on 3-dimensional reconstruction of nasolabial muscle fibers.

PubMed

Yin, Ningbei; Wu, Jiajun; Chen, Bo; Song, Tao; Ma, Hengyuan; Zhao, Zhenmin; Wang, Yongqian; Li, Haidong; Wu, Di

2015-03-01

Plastic surgeons have attempted various ways to rebuild the aesthetic subunits of the upper lip in patients with cleft lip with less than perfect results in most cases. We propose that repairing the 3 muscle tension line groups in the nasolabial complex will have improved aesthetic results. Micro-computed tomographic scans were performed on the nasolabial tissues of 5 normal aborted fetuses and used to construct a 3-dimensional model to study the nasolabial muscle complex structure. The micro-computed tomographic (CT) scans showed the close relationship and interaction between the muscle fibers of nasalis, pars peripheralis, levator labii superioris, and pars marginalis. Based on the 2-dimensional images obtained from the micro-computed tomographic scans, we suggest the concept of nasolabial muscle complex and muscle tension line group theory: there is a close relationship among the alar part of the nasalis, depressor septi muscle, orbicularis oris muscle, and levator labii superioris alaeque nasi. The tension line groups are 3 tension line structures in the nasolabial muscle complex that interlock with each other at the intersections and maintain the specific shape and aesthetics of the lip and nose.

Characteristics and significance of doublets on needle EMG.

PubMed

Lamb, Christopher J; Rubin, Devon I

2017-04-01

Voluntary doublets are electrophysiological phenomena thought to be associated with metabolic derangements or neuromuscular conditions. We prospectively studied 232 consecutive patients examined by a single examiner during routine electromyography (EMG) to determine the frequency of doublets in individual patients, specific muscles, neuromuscular conditions, electrolyte levels, and doublet characteristics. Of 232 patients, 25 (10.7%) exhibited doublets. The mean age was 59 (52% men). Only 32 of 1,303 (2.5%) muscles exhibited doublets. Lower extremity and paraspinal groups represented 91% of muscles with doublets. Doublet frequency grouped by EMG diagnoses was: ALS (3 of 11; 27.1%), myopathy (3 of 10; 30.0%), axonal polyneuropathy (7 of 29; 24.1%), and no disease (7 of 109; 6.4%). There were no differences in serum electrolytes between doublet and matched subjects. Doublets occur in approximately 10% of patients, more commonly in lower extremity and paraspinal muscles, and are not correlated with a specific metabolic abnormality or neuromuscular condition. Muscle Nerve 55: 598-600, 2017. © 2016 Wiley Periodicals, Inc.

Ultrasonography to Measure Swallowing Muscle Mass and Quality in Older Patients With Sarcopenic Dysphagia.

PubMed

Ogawa, Nami; Mori, Takashi; Fujishima, Ichiro; Wakabayashi, Hidetaka; Itoda, Masataka; Kunieda, Kenjiro; Shigematsu, Takashi; Nishioka, Shinta; Tohara, Haruka; Yamada, Minoru; Ogawa, Sumito

2018-06-01

Sarcopenic dysphagia is characterized by difficulty swallowing due to a loss of whole-body skeletal and swallowing muscle mass and function. However, no study has reported on swallowing muscle mass and quality in patients with sarcopenic dysphagia. To compare the differences in swallowing muscle mass and quality between sarcopenic and nonsarcopenic dysphagia. A cross-sectional study was performed in 55 older patients, who had been recommended to undergo dysphagia assessment and/or rehabilitation. Sarcopenic dysphagia was diagnosed using a diagnostic algorithm for sarcopenic dysphagia. The thickness and area of tongue muscle and geniohyoid muscle (coronal plane and sagittal plane), and the echo-intensity of the tongue and geniohyoid muscles were examined by ultrasound. The study participants included 31 males and 24 females (mean age of 82 ± 7 years), with 14 having possible sarcopenic dysphagia, 22 probable sarcopenic dysphagia, and 19 without sarcopenic dysphagia. The group with sarcopenic dysphagia had a significantly lower cross-sectional area and area of brightness of the tongue muscle than that observed in the group without sarcopenic dysphagia. The most specific factor for identifying the presence of sarcopenic dysphagia was tongue muscle area (sensitivity, 0.389; specificity, 0.947; cut-off value, 1536.0), while the factor with the highest sensitivity was geniohyoid muscle area brightness in sagittal sections (sensitivity, 0.806; specificity, 0.632; cut-off value, 20.1). Multivariate logistic regression analysis showed that the area of the tongue muscle and its area of brightness were independent risk factors for sarcopenic dysphagia. However, geniohyoid sagittal muscle area and area of brightness showed no significant independent association with sarcopenic dysphagia. Tongue muscle mass in patients with sarcopenic dysphagia was smaller than that in patients without the condition. Sarcopenic dysphagia was also associated with increased intensity of the tongue muscle. Copyright © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

A review of the anatomy of the hip abductor muscles, gluteus medius, gluteus minimus, and tensor fascia lata.

PubMed

Flack, Natasha Amy May Sparks; Nicholson, Helen D; Woodley, Stephanie Jane

2012-09-01

The hip abductor muscles have the capability to contribute to numerous actions, including pelvic stabilization during gait, and abduction and rotation at the hip joint. To fully understand the role of these muscles, as well as their involvement in hip joint dysfunction, knowledge of their anatomical structure is essential. The clinical literature suggests anatomical diversity within these muscles, and that gluteus medius (GMed) and gluteus minimus (GMin), in particular, may be comprised of compartments. This systematic review of the English literature focuses on the gross anatomy of GMed, GMin, and tensor fascia lata (TFL) muscles. Although studies of this muscle group have generated useful descriptions, comparison of results is hindered by methodological limitations. Furthermore, there is no single comprehensive anatomical investigation of all three muscles. Several aspects of the morphology of attachment sites are unknown or unclear. There is little data on fascicle orientation, the interface between fascicles and tendons, and the specific patterning of the superior gluteal nerve. Consequently, the existence of anatomical compartmentalization within the hip abductor muscles is difficult to assess. Further research of the architecture and innervation of the hip abductor muscle group is required; a better understanding of the precise anatomy of these muscles should improve our understanding of their specific functions and their contribution to the pathogenesis of disorders affecting the hip joint. Copyright © 2011 Wiley Periodicals, Inc.

Altered mitochondrial bioenergetics and ultrastructure in the skeletal muscle of young adults with type 1 diabetes.

PubMed

Monaco, Cynthia M F; Hughes, Meghan C; Ramos, Sofhia V; Varah, Nina E; Lamberz, Christian; Rahman, Fasih A; McGlory, Chris; Tarnopolsky, Mark A; Krause, Matthew P; Laham, Robert; Hawke, Thomas J; Perry, Christopher G R

2018-06-01

A comprehensive assessment of skeletal muscle ultrastructure and mitochondrial bioenergetics has not been undertaken in individuals with type 1 diabetes. This study aimed to systematically assess skeletal muscle mitochondrial phenotype in young adults with type 1 diabetes. Physically active, young adults (men and women) with type 1 diabetes (HbA 1c 63.0 ± 16.0 mmol/mol [7.9% ± 1.5%]) and without type 1 diabetes (control), matched for sex, age, BMI and level of physical activity, were recruited (n = 12/group) to undergo vastus lateralis muscle microbiopsies. Mitochondrial respiration (high-resolution respirometry), site-specific mitochondrial H 2 O 2 emission and Ca 2+ retention capacity (CRC) (spectrofluorometry) were assessed using permeabilised myofibre bundles. Electron microscopy and tomography were used to quantify mitochondrial content and investigate muscle ultrastructure. Skeletal muscle microvasculature was assessed by immunofluorescence. Mitochondrial oxidative capacity was significantly lower in participants with type 1 diabetes vs the control group, specifically at Complex II of the electron transport chain, without differences in mitochondrial content between groups. Muscles of those with type 1 diabetes also exhibited increased mitochondrial H 2 O 2 emission at Complex III and decreased CRC relative to control individuals. Electron tomography revealed an increase in the size and number of autophagic remnants in the muscles of participants with type 1 diabetes. Despite this, levels of the autophagic regulatory protein, phosphorylated AMP-activated protein kinase (p-AMPKα Thr172 ), and its downstream targets, phosphorylated Unc-51 like autophagy activating kinase 1 (p-ULK1 Ser555 ) and p62, was similar between groups. In addition, no differences in muscle capillary density or platelet aggregation were observed between the groups. Alterations in mitochondrial ultrastructure and bioenergetics are evident within the skeletal muscle of active young adults with type 1 diabetes. It is yet to be elucidated whether more rigorous exercise may help to prevent skeletal muscle metabolic deficiencies in both active and inactive individuals with type 1 diabetes.

The neural response properties and cortical organization of a rapidly adapting muscle sensory group response that overlaps with the frequencies that elicit the kinesthetic illusion.

PubMed

Marasco, Paul D; Bourbeau, Dennis J; Shell, Courtney E; Granja-Vazquez, Rafael; Ina, Jason G

2017-01-01

Kinesthesia is the sense of limb movement. It is fundamental to efficient motor control, yet its neurophysiological components remain poorly understood. The contributions of primary muscle spindles and cutaneous afferents to the kinesthetic sense have been well studied; however, potential contributions from muscle sensory group responses that are different than the muscle spindles have not been ruled out. Electrophysiological recordings in peripheral nerves and brains of male Sprague Dawley rats with a degloved forelimb preparation provide evidence of a rapidly adapting muscle sensory group response that overlaps with vibratory inputs known to generate illusionary perceptions of limb movement in humans (kinesthetic illusion). This group was characteristically distinct from type Ia muscle spindle fibers, the receptor historically attributed to limb movement sensation, suggesting that type Ia muscle spindle fibers may not be the sole carrier of kinesthetic information. The sensory-neural structure of muscles is complex and there are a number of possible sources for this response group; with Golgi tendon organs being the most likely candidate. The rapidly adapting muscle sensory group response projected to proprioceptive brain regions, the rodent homolog of cortical area 3a and the second somatosensory area (S2), with similar adaption and frequency response profiles between the brain and peripheral nerves. Their representational organization was muscle-specific (myocentric) and magnified for proximal and multi-articulate limb joints. Projection to proprioceptive brain areas, myocentric representational magnification of muscles prone to movement error, overlap with illusionary vibrational input, and resonant frequencies of volitional motor unit contraction suggest that this group response may be involved with limb movement processing.

The neural response properties and cortical organization of a rapidly adapting muscle sensory group response that overlaps with the frequencies that elicit the kinesthetic illusion

PubMed Central

Marasco, Paul D.; Bourbeau, Dennis J.; Shell, Courtney E.; Granja-Vazquez, Rafael; Ina, Jason G.

2017-01-01

Kinesthesia is the sense of limb movement. It is fundamental to efficient motor control, yet its neurophysiological components remain poorly understood. The contributions of primary muscle spindles and cutaneous afferents to the kinesthetic sense have been well studied; however, potential contributions from muscle sensory group responses that are different than the muscle spindles have not been ruled out. Electrophysiological recordings in peripheral nerves and brains of male Sprague Dawley rats with a degloved forelimb preparation provide evidence of a rapidly adapting muscle sensory group response that overlaps with vibratory inputs known to generate illusionary perceptions of limb movement in humans (kinesthetic illusion). This group was characteristically distinct from type Ia muscle spindle fibers, the receptor historically attributed to limb movement sensation, suggesting that type Ia muscle spindle fibers may not be the sole carrier of kinesthetic information. The sensory-neural structure of muscles is complex and there are a number of possible sources for this response group; with Golgi tendon organs being the most likely candidate. The rapidly adapting muscle sensory group response projected to proprioceptive brain regions, the rodent homolog of cortical area 3a and the second somatosensory area (S2), with similar adaption and frequency response profiles between the brain and peripheral nerves. Their representational organization was muscle-specific (myocentric) and magnified for proximal and multi-articulate limb joints. Projection to proprioceptive brain areas, myocentric representational magnification of muscles prone to movement error, overlap with illusionary vibrational input, and resonant frequencies of volitional motor unit contraction suggest that this group response may be involved with limb movement processing. PMID:29182648

Evaluating swallowing muscles essential for hyolaryngeal elevation by using muscle functional magnetic resonance imaging.

PubMed

Pearson, William G; Hindson, David F; Langmore, Susan E; Zumwalt, Ann C

2013-03-01

Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Muscles of both the suprahyoid and the longitudinal pharyngeal muscle groups are active in swallowing, and both swallowing exercises effectively target muscles elevating the hyolaryngeal complex. mfMRI is useful in testing swallowing muscle function. Copyright © 2013 Elsevier Inc. All rights reserved.

Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pearson, William G., E-mail: bp1@bu.edu; Hindson, David F.; Langmore, Susan E.

2013-03-01

Purpose: Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercisesmore » thought to be specific to hyolaryngeal elevation. Methods and Materials: mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Results: Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Conclusions: Muscles of both the suprahyoid and the longitudinal pharyngeal muscle groups are active in swallowing, and both swallowing exercises effectively target muscles elevating the hyolaryngeal complex. mfMRI is useful in testing swallowing muscle function.« less

Discriminant musculo-skeletal leg characteristics between sprint and endurance elite Caucasian runners.

PubMed

Bex, T; Iannaccone, F; Stautemas, J; Baguet, A; De Beule, M; Verhegghe, B; Aerts, P; De Clercq, D; Derave, W

2017-03-01

Excellence in either sprinting or endurance running requires specific musculo-skeletal characteristics of the legs. This study aims to investigate the morphology of the leg of sprinters and endurance runners of Caucasian ethnicity. Eight male sprinters and 11 male endurance runners volunteered to participate in this cross-sectional study. They underwent magnetic resonance imaging and after data collection, digital reconstruction was done to calculate muscle volumes and bone lengths. Sprinters have a higher total upper leg volume compared to endurance runners (7340 vs 6265 cm 3 ). Specifically, the rectus femoris, vastus lateralis, and hamstrings showed significantly higher muscle volumes in the sprint group. For the lower leg, only a higher muscle volume was found in the gastrocnemius lateralis for the sprinters. No differences were found in muscle volume distribution, center of mass in the different muscles, or relative bone lengths. There was a significant positive correlation between ratio hamstrings/quadriceps volume and best running performance in the sprint group. Sprinters and endurance runners of Caucasian ethnicity showed the greatest distinctions in muscle volumes, rather than in muscle distributions or skeletal measures. Sprinters show higher volumes in mainly the proximal and lateral leg muscles than endurance runners. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The effect of different exercise programs on cervical flexor muscles dimensions in patients with chronic neck pain.

PubMed

Javanshir, Khodabakhsh; Amiri, Mohsen; Mohseni Bandpei, Mohammad Ali; De las Penas, Cesar Fernandez; Rezasoltani, Asghar

2015-01-01

The effect of different exercise programs on cervical flexor muscles dimensions in patients with chronic neck pain is yet to be demonstrated. The purpose of this study was to assess the effect of two exercise programs; craniocervical flexion (CCF) and cervical flexion (CF), on flexor muscles dimensions in patients with chronic neck pain. Following ethical approval, 60 patients were randomly assigned into either a CCF group or a CF group. Patients in the CCF group were given CCF exercises and those in the CF group received CF exercises. All patients received interventions for a period of ten weeks. Pain intensity and functional disability were assessed using numerical pain rate scale and neck disability index, respectively. Dimensions of longus colli (LC) and sternoclidomastoid (SCM) muscles were measured using ultrasonography (US). All measurements were taken before and after interventions. Following intervention, the CCF group demonstrated a significant increase in LC muscle dimensions including cross sectional area, width and thickness compared with the CF group. A statistically significant increase was found on SCM thickness in the CF group. Following intervention, SCM thickness measurement in the CCF group showed no significant changes. Statistically significant decrease on pain intensity and disability were also found in both groups. Present findings demonstrated that craniocervical flexion program which specifically recruiting deep cervical flexor muscles increased LC muscle dimension significantly and CF program as an endurance training program increased SCM thickness.

Pre-operative inspiratory muscle training preserves postoperative inspiratory muscle strength following major abdominal surgery - a randomised pilot study.

PubMed

Kulkarni, S R; Fletcher, E; McConnell, A K; Poskitt, K R; Whyman, M R

2010-11-01

The aim of this pilot study was to assess the effect of pre-operative inspiratory muscle training (IMT) on respiratory variables in patients undergoing major abdominal surgery. Respiratory muscle strength (maximum inspiratory [MIP] and expiratory [MEP] mouth pressure) and pulmonary functions were measured at least 2 weeks before surgery in 80 patients awaiting major abdominal surgery. Patients were then allocated randomly to one of four groups (Group A, control; Group B, deep breathing exercises; Group C, incentive spirometry; Group D, specific IMT). Patients in groups B, C and D were asked to train twice daily, each session lasting 15 min, for at least 2 weeks up to the day before surgery. Outcome measurements were made immediately pre-operatively and postoperatively. In groups A, B and C, MIP did not increase from baseline to pre-operative assessments. In group D, MIP increased from 51.5 cmH(2)O (median) pre-training to 68.5 cmH(2)O (median) post-training pre-operatively (P < 0.01). Postoperatively, groups A, B and C showed a fall in MIP from baseline (P < 0.01, P < 0.01) and P = 0.06, respectively). No such significant reduction in postoperative MIP was seen in group D (P = 0.36). Pre-operative specific IMT improves MIP pre-operatively and preserves it postoperatively. Further studies are required to establish if this is associated with reduced pulmonary complications.

Distal Traditional Acupuncture Points of the Large Intestinal Meridian and the Stomach Meridian Differently Affect Heart Rate Variability and Oxygenation of the Trapezius Muscle

PubMed Central

Shiro, Yukiko; Arai, Young-Chang P.; Ikemoto, Tatsunori; Kawai, Takashi; Ikeuchi, Masahiko; Ushida, Takahiro

2014-01-01

Physicians in traditional Chinese medicine have found that acupoints and meridians have effects on specific parts of the body. The aim of this study was to see how acupressure at distal acupuncture points of a specific meridian affects heart rate variability (HRV) and oxygenation of the trapezius muscle. Forty-one female participants were randomly allocated to three groups. Subjects in the Stomach Meridian acupuncture point (ST) group received acupressure at ST 34, ST 36, and ST 41, subjects in the Large Intestinal Meridian acupuncture point (LI) group received acupressure at LI 4, LI 10, and LI 11, and subjects in the control group did not receive any stimuli. HRV and oxygenation of the trapezius muscles were measured. The high frequency components of HRV in the control and LI groups tended to be higher than those in the ST group. Total hemoglobin in the control and LI groups eventually reached significantly higher levels than in the ST group. While oxyhemoglobin (ΔO2Hb) in the control and LI groups did not change, ΔO2Hb in the ST significantly decreased temporarily. PMID:24696701

Muscle Contractile Properties in Severely Burned Rats

PubMed Central

Wu, Xiaowu; Wolf, Steven E.; Walters, Thomas J.

2010-01-01

Burn induces a sustained catabolic response which causes massive loss of muscle mass after injury. A better understanding of the dynamics of muscle wasting and its impact on muscle function is necessary for the development of effective treatments. Male Sprague-Dawley rats underwent either a 40% total body surface area (TBSA) scald burn or sham burn, and were further assigned to subgroups at four time points after injury (days 3, 7, 14 and 21). In situ isometric contractile properties were measured including twitch tension (Pt), tetanic tension (Po) and fatigue properties. Body weight decreased in burn and sham groups through day 3, however, body weight in the sham groups recovered and increased over time compared to burned groups, which progressively decreased until day 21 after injury. Significant differences in muscle wet weight and protein weight were found between sham and burn. Significant differences in muscle contractile properties were found at day 14 with lower absolute Po as well as specific Po in burned rats compared to sham. After burn, the muscle twitch tension was significantly higher than the sham at day 21. No significant difference in fatigue properties was found between the groups. This study demonstrates dynamics of muscle atrophy and muscle contractile properties after severe burn; this understanding will aid in the development of approaches designed to reduce the rate and extent of burn induced muscle loss and function. PMID:20381255

Reorganization of muscle activity in patients with chronic temporomandibular disorders.

PubMed

Mapelli, Andrea; Zanandréa Machado, Bárbara Cristina; Giglio, Lucia Dantas; Sforza, Chiarella; De Felício, Cláudia Maria

2016-12-01

To investigate whether reorganization of muscle activity occurs in patients with chronic temporomandibular disorders (TMD) and, if so, how it is affected by symptomatology severity. Surface electromyography (sEMG) of masticatory muscles was made in 30 chronic TMD patients, diagnosed with disc displacement with reduction (DDR) and pain. Two 15-patient subgroups, with moderate (TMDmo) and severe (TMDse) signs and symptoms, were compared with a control group of 15 healthy subjects matched by age. The experimental tasks were: a 5s inter-arch maximum voluntary clench (MVC); right and left 15s unilateral gum chewing tests. Standardized sEMG indices characterizing masseter and temporalis muscles activity were calculated, and a comprehensive functional index (FI) was introduced to quantitatively summarize subjects' overall performance. Mastication was also clinically evaluated. During MVC, TMDse patients had a significantly larger asymmetry of temporalis muscles contraction. Both TMD groups showed reduced coordination between masseter and temporalis muscles' maximal contraction, and their muscular activity distribution shifted significantly from masseter to temporalis muscles. During chewing, TMDse patients recruited the balancing side muscles proportionally more than controls, specifically the masseter muscle. When comparing right and left side chewing, the muscles' recruitment pattern resulted less symmetric in TMD patients, especially in TMDse. Overall, the functional index of both TMDmo and TMDse patients was significantly lower than that obtained by controls. Chronic TMD patients, specifically those with severe symptomatology, showed a reorganized activity, mainly resulting in worse functional performances. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neuromuscular performance of lower limbs during voluntary and reflex activity in power- and endurance-trained athletes.

PubMed

Kyröläinen, H; Komi, P V

1994-01-01

Neural, mechanical and muscle factors influence muscle force production. This study was therefore, designed to compare possible differences in the function of the neuromuscular system among differently adapted subjects. A group of 11 power-trained athletes and 10 endurance-trained athletes volunteered as subjects for this study. Maximal voluntary isometric force and the rate of force production of the knee extensor and the plantar flexor muscles were measured. In addition, basic reflex function was measured in the two experimental conditions. The power athletes produced higher voluntary forces (P < 0.01-0.001) with higher rates for force production (P < 0.001) by both muscle groups measured. Unexpectedly, however, no differences were noticed in the electromyogram time curves between the groups. During reflex activity, the endurance group demonstrated higher sensitivity to the mechanical stimuli, i.e. the higher reflex amplitude caused a higher rate of reflex force development, and the reflex amplitude correlated with the averaged angular velocity. The differences in the isometric conditions could be explained by obviously different muscle fibre distribution, by different amounts of muscle mass, by possible differences in the force transmission from individual myofibrils to the skeletal muscle and by specificity of training. In addition, differences in nervous system structure and muscle spindle properties could explain the observed differences in reflex activity between the two groups.

Muscle dysmorphia: methodological issues, implications for research.

PubMed

Suffolk, Mark T; Dovey, Terence M; Goodwin, Huw; Meyer, Caroline

2013-01-01

Muscle dysmorphia is a male-dominated, body image-related psychological condition. Despite continued investigation, contention surrounds the nosological status of this disorder. The aim of this article was to review the literature on muscle dysmorphia to provide a qualitative account of methodological issues that may inhibit our understanding. Key areas relating to non-standardized participant groups, measuring instruments, and terminology were identified as potentially inhibiting symptom coherence and diagnostic reliability. New measuring instruments validated with clinical samples and carefully described participant groups, standardized terminology, and a greater emphasis on prospective longitudinal research with specific sub groups of the weight training community would be of interest to the field.

The effect of material characteristics of shoe soles on muscle activation and energy aspects during running.

PubMed

Nigg, B M; Stefanyshyn, D; Cole, G; Stergiou, P; Miller, J

2003-04-01

The purposes of this study were (a) to determine group and individual differences in oxygen consumption during heel-toe running and (b) to quantify the differences in EMG activity for selected muscle groups of the lower extremities when running in shoes with different mechanical heel characteristics. Twenty male runners performed heel-toe running using two shoe conditions, one with a mainly elastic and a visco-elastic heel. Oxygen consumption was quantified during steady state runs of 6 min duration, running slightly above the aerobic threshold providing four pairs of oxygen consumption results for comparison. Muscle activity was quantified using bipolar surface EMG measurements from the tibialis anterior, medial gastrocnemius, vastus medialis and the hamstrings muscle groups. EMG data were sampled for 5 s every minute for the 6 min providing 30 trials. EMG data were compared for the different conditions using an ANOVA (alpha=0.05). The findings of this study showed that changes in the heel material characteristics of running shoes were associated with (a) subject specific changes in oxygen consumption and (b) subject and muscle specific changes in the intensities of muscle activation before heel strike in the lower extremities. It is suggested that further study of these phenomena will help understand many aspects of human locomotion, including work, performance, fatigue and possible injuries.

Mild aerobic training with blood flow restriction increases the hypertrophy index and MuSK in both slow and fast muscles of old rats: Role of PGC-1α.

PubMed

Bahreinipour, Mohammad-Ali; Joukar, Siyavash; Hovanloo, Fariborz; Najafipour, Hamid; Naderi, Vida; Rajiamirhasani, Alireza; Esmaeili-Mahani, Saeed

2018-06-01

Existing evidence emphasize the role of mitochondrial dysfunction in sarcopenia which is revealed as loss of skeletal muscle mass and neuromuscular junction remodeling. We assessed the effect of low-intensity aerobic training along with blood flow restriction on muscle hypertrophy index, muscle-specific kinase (MuSK), a pivotal protein of the neuromuscular junction and Peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC-1α) in aged male rats. Animals groups were control (CTL), sham (Sh), leg blood flow restriction (BFR), exercise (Ex), sham + exercise (Sh + Ex), and BFR plus exercise (BFR + Ex) groups. The exercise groups were trained with low intensity exercise for 10 weeks. 48 h after the last training session, animals were sacrificed under anesthesia. Soleus and EDL muscles were isolated, hypertrophy index was estimated and MuSK and PGC-1α were measured by western blot method. Hypertrophy index enhanced in soleus and Extensor digitorum longus (EDL) muscles of BFR + Ex group (P < 0.01 versus CTL and Sh groups, and P < 0.001 versus other groups). The MuSK protein of soleus and EDL muscles increased in BFR + Ex group (P < 0.01 and P < 0.001, respectively) in comparison with CTL and Sh groups. In BFR + Ex group, the PGC-1α protein increased in both soleus and EDL (P < 0.001 compared to other groups). Also the PGC-1α of soleus muscle was higher in Ex and Sh + Ex groups versus CTL and Sh groups (P < 0.05). Findings suggest that low endurance exercise plus BFR improves the MuSK and hypertrophy index of both slow and fast muscles of elderly rats probably through the rise of PGC-1α expression. Copyright © 2018. Published by Elsevier Inc.

Broad and Inconsistent Muscle Food Classification Is Problematic for Dietary Guidance in the U.S.

PubMed Central

O’Connor, Lauren E.; Campbell, Wayne W.; Woerner, Dale R.; Belk, Keith E.

2017-01-01

Dietary recommendations regarding consumption of muscle foods, such as red meat, processed meat, poultry or fish, largely rely on current dietary intake assessment methods. This narrative review summarizes how U.S. intake values for various types of muscle foods are grouped and estimated via methods that include: (1) food frequency questionnaires; (2) food disappearance data from the U.S. Department of Agriculture Economic Research Service; and (3) dietary recall information from the National Health and Nutrition Examination Survey data. These reported methods inconsistently classify muscle foods into groups, such as those previously listed, which creates discrepancies in estimated intakes. Researchers who classify muscle foods into these groups do not consistently considered nutrient content, in turn leading to implications of scientific conclusions and dietary recommendations. Consequentially, these factors demonstrate a need for a more universal muscle food classification system. Further specification to this system would improve accuracy and precision in which researchers can classify muscle foods in nutrition research. Future multidisciplinary collaboration is needed to develop a new classification system via systematic review protocol of current literature. PMID:28926963

Morphology of the lumbar transversospinal muscles examined in a mouse bearing a muscle fiber-specific nuclear marker.

PubMed

Cornwall, Jon; Deries, Marianne; Duxson, Marilyn

2010-12-01

Although the morphology of human lumbar transversospinal (TSP) muscles has been studied, little is known about the structure of these muscles in the mouse (Mus musculus). Such information is relevant given mice are often used as a "normal" phenotype for studies modeling human development. This study describes the gross morphology, muscle fiber arrangement, and innervation pattern of the mouse lumbar TSP muscles. A unique feature of the study is the use of a transgenic mouse line bearing a muscle-specific nuclear marker that allows clear delineation of muscle fiber and connective tissue boundaries. The lumbar TSP muscles of five mice were examined bilaterally; at each spinal level muscles attached to the caudal edge of the spinous process and passed caudally as a single complex unit. Fibers progressively terminated over the four vertebral segments caudad, with multiple points of muscle fiber attachment on each vertebra. Motor endplates, defined with acetylcholinesterase histochemistry, were consistently located half way along each muscle fiber, regardless of length, with all muscle fibers arranged in-parallel rather than in-series. These results provide information relevant to interpretation of developmental and functional studies involving this muscle group in the mouse and show mouse lumbar TSP muscles are different in form to descriptions of equivalent muscles in humans and horses.

Oestrogen receptor-alpha activation augments post-exercise myoblast proliferation.

PubMed

Thomas, A; Bunyan, K; Tiidus, P M

2010-01-01

Our laboratory has shown that oestrogen acts to augment myoblast (satellite cell) activation, proliferation and total number and that this may occur through an oestrogen receptor (OR)-mediated mechanism. The purpose of this study was to further investigate the mechanism of oestrogen influence on augmentation of post-exercise myoblast numbers through use of a specific OR-alpha agonist, propyl pyrazole triol (PPT). Ovariectomized rats were used (n = 64) and separated into four groups: sham, oestrogen supplemented, agonist supplemented, and a combined oestrogen and agonist supplemented group. These groups were further subdivided into control (unexercised) and exercise groups. Surgical removal of white vastus and soleus muscles was performed 72 h post-exercise. Muscle samples were immunostained for the myoblast markers Pax7 and MyoD. A significant increase in total (Pax7-positive) and activated (MyoD-positive) myoblasts was found in all groups post-exercise. A further significant augmentation of total and activated myoblasts occurred in oestrogen supplemented, agonist supplemented and the combined oestrogen and agonist supplemented groups post-exercise in white vastus and soleus muscles relative to unsupplemented animals. These results demonstrate that both oestrogen and the specific OR-alpha receptor agonist, PPT, can significantly and to similar degrees augment myoblast number and activation following exercise-induced muscle damage. This suggests that oestrogen acts through an OR-mediated mechanism to stimulate myoblast proliferation following exercise, with OR-alpha playing a primary role.

Supplementing healthy rats with a high-niacin dose has no effect on muscle fiber distribution and muscle metabolic phenotype.

PubMed

Scholz, Kristen; Kynast, Anna Marie; Couturier, Aline; Mooren, Frank-Christoph; Krüger, Karsten; Most, Erika; Eder, Klaus; Ringseis, Robert

2014-08-01

It was recently shown that niacin prevents the obesity-induced type I to type II fiber switching in skeletal muscle of obese rats and favors the development of a more oxidative metabolic phenotype and thereby increases whole body utilization of fatty acids. Whether niacin also causes type II to type I fiber switching in skeletal muscle of healthy rats has not been investigated yet. Thus, the present study aimed to investigate whether niacin supplementation influences fiber distribution and metabolic phenotype of different skeletal muscles with a distinct type I-to-type II fiber ratio in healthy rats. Twenty-four male, 10-week-old Sprague-Dawley rats were randomly assigned into two groups of 12 rats each and fed either a control diet with 30 mg supplemented niacin/kg diet (control group) or a high-niacin diet with 780 mg supplemented niacin/kg diet (high-niacin group). After 27 days of treatment, the percentage number of type I fibers in rectus femoris, gastrocnemius, and tibialis anterior muscles was 5-10% greater in the niacin group than in the control group, but did not differ between groups in soleus and vastus intermedius muscles. Transcript levels of genes encoding transcription factors regulating fiber switching, fiber-specific myosin heavy chain isoforms, and proteins involved in fatty acid utilization, oxidative phosphorylation, and angiogenesis did not differ between groups. The results show that niacin has only negligible effects on fiber distribution and its regulation as well as the metabolic phenotype of skeletal muscle in healthy rats.

Scaling of muscle architecture and fiber types in the rat hindlimb.

PubMed

Eng, Carolyn M; Smallwood, Laura H; Rainiero, Maria Pia; Lahey, Michele; Ward, Samuel R; Lieber, Richard L

2008-07-01

The functional capacity of a muscle is determined by its architecture and metabolic properties. Although extensive analyses of muscle architecture and fiber type have been completed in a large number of muscles in numerous species, there have been few studies that have looked at the interrelationship of these functional parameters among muscles of a single species. Nor have the architectural properties of individual muscles been compared across species to understand scaling. This study examined muscle architecture and fiber type in the rat (Rattus norvegicus) hindlimb to examine each muscle's functional specialization. Discriminant analysis demonstrated that architectural properties are a greater predictor of muscle function (as defined by primary joint action and anti-gravity or non anti-gravity role) than fiber type. Architectural properties were not strictly aligned with fiber type, but when muscles were grouped according to anti-gravity versus non-anti-gravity function there was evidence of functional specialization. Specifically, anti-gravity muscles had a larger percentage of slow fiber type and increased muscle physiological cross-sectional area. Incongruities between a muscle's architecture and fiber type may reflect the variability of functional requirements on single muscles, especially those that cross multiple joints. Additionally, discriminant analysis and scaling of architectural variables in the hindlimb across several mammalian species was used to explore whether any functional patterns could be elucidated within single muscles or across muscle groups. Several muscles deviated from previously described muscle architecture scaling rules and there was large variability within functional groups in how muscles should be scaled with body size. This implies that functional demands placed on muscles across species should be examined on the single muscle level.

Protein Supplementation Augments Muscle Fiber Hypertrophy but Does Not Modulate Satellite Cell Content During Prolonged Resistance-Type Exercise Training in Frail Elderly.

PubMed

Dirks, Marlou L; Tieland, Michael; Verdijk, Lex B; Losen, Mario; Nilwik, Rachel; Mensink, Marco; de Groot, Lisette C P G M; van Loon, Luc J C

2017-07-01

Protein supplementation increases gains in lean body mass following prolonged resistance-type exercise training in frail older adults. We assessed whether the greater increase in lean body mass can be attributed to muscle fiber type specific hypertrophy with concomitant changes in satellite cell (SC) content. A total of 34 frail elderly individuals (77 ± 1 years, n = 12 male adults) participated in this randomized, double-blind, placebo-controlled trial with 2 arms in parallel. Participants performed 24 weeks of progressive resistance-type exercise training (2 sessions per week) during which they were supplemented twice-daily with milk protein (2 × 15 g) or a placebo. Muscle biopsies were taken at baseline, and after 12 and 24 weeks of intervention, to determine type I and type II muscle fiber specific cross-sectional area (CSA), SC content, and myocellular characteristics. In the placebo group, a trend for a 20% ± 11% increase in muscle fiber CSA was observed in type II fibers only (P = .051), with no increase in type I muscle fiber CSA. In the protein group, type I and II muscle fiber CSA increased by 23% ± 7% and 34% ± 10% following 6 months of training, respectively (P < .01). Myonuclear domain size increased over time in both groups and fiber types (P < .001), with no significant differences between groups (P > .05). No changes in myonuclear content and SC contents were observed over time in either group (both P > .05). Regression analysis showed that changes in myonuclear content and domain size are predictive of muscle fiber hypertrophy. Protein supplementation augments muscle fiber hypertrophy following prolonged resistance-type exercise training in frail older people, without changes in myonuclear and SC content. Copyright © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

Similar efficacy from specific and non-specific mineralocorticoid receptor antagonist treatment of muscular dystrophy mice.

PubMed

Lowe, Jeovanna; Floyd, Kyle T; Rastogi, Neha; Schultz, Eric J; Chadwick, Jessica A; Swager, Sarah A; Zins, Jonathan G; Kadakia, Feni K; Smart, Suzanne; Gomez-Sanchez, Elise P; Gomez-Sanchez, Celso E; Raman, Subha V; Janssen, Paul M L; Rafael-Fortney, Jill A

2016-01-01

Combined treatment with an angiotensin-converting enzyme inhibitor and a mineralocorticoid receptor (MR) antagonist improved cardiac and skeletal muscle function and pathology in a mouse model of Duchenne muscular dystrophy. MR is present in limb and respiratory skeletal muscles and functions as a steroid hormone receptor. The goals of the current study were to compare the efficacy of the specific MR antagonist eplerenone with the non-specific MR antagonist spironolactone, both in combination with the angiotensin-converting enzyme inhibitor lisinopril. Three groups of n=18 dystrophin-deficient, utrophin-haploinsufficient male mice were given chow containing: lisinopril plus spironolactone, lisinopril plus eplerenone, or no drug, from four to 20 weeks-of-age. Eighteen C57BL/10 male mice were used as wild-type controls. In vivo measurements included cardiac magnetic resonance imaging, conscious electrocardiography, and grip strength. From each mouse in the study, diaphragm, extensor digitorum longus , and cardiac papillary muscle force was measured ex vivo , followed by histological quantification of muscle damage in heart, diaphragm, quadriceps, and abdominal muscles. MR protein levels were also verified in treated muscles. Treatment with specific and non-specific MR antagonists did not result in any adverse effects to dystrophic skeletal muscles or heart. Both treatments resulted in similar functional and pathological improvements across a wide array of parameters. MR protein levels were not reduced by treatment. These data suggest that spironolactone and eplerenone show similar effects in dystrophic mice and support the clinical development of MR antagonists for treating skeletal muscles in Duchenne muscular dystrophy.

Effects of specific muscle imbalance improvement training on the balance ability in elite fencers.

PubMed

Kim, Taewhan; Kil, Sekee; Chung, Jinwook; Moon, Jeheon; Oh, Eunyoung

2015-05-01

[Purpose] The lunge Motion that occurs frequently in fencing training and matches results in imbalance of the upper and lower limbs muscles. This research focuses on the improvement of the imbalance that occurs in the national team fencers of the Republic of Korea through specific muscle imbalance improvement training. [Subjects] The subjects of this research were limited to right-handed male fencers. Nine male, right-handed national fencing athletes were selected for this study (4 epee, 5 sabre; age 28.2 ± 2.2 years; height 182.3 ± 4.0 cm; weight 76.5 ± 8.2 kg; experience 12.4 ± 3.0 years). [Methods] The specific muscle imbalance improvement training program was performed for 12 weeks and Pre-Post tests were to evaluate its effect on the experimental group. Measurements comprised anthropometry, test of balance, and movement analysis. [Results] After the training program, mediolateral sway of the nondominant lower limb and the balance scale showed statistically significant improvement. [Conclusion] The specific muscle imbalance improvement training program used in this research was proven to be effective for improving the muscle imbalance of elite fencers.

Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

PubMed Central

Pearson, William G.; Hindson, David F.; Langmore, Susan E.; Zumwalt, Ann C.

2012-01-01

Summary Elevation of the larynx is critical to swallowing function, an observation supported by the fact that radiation therapy-induced dysphagia is associated with reduced laryngeal elevation. We investigated muscles underlying hyolaryngeal elevation by using muscle functional MRI. We acquired scans from 11 healthy subjects to determine whole-muscle T2 signal profiles pre-swallowing, post-swallowing, and after performing swallowing exercises. Results demonstrate muscles essential to laryngeal elevation and exercises that target them. Purpose Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. Methods and Materials mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Results Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Conclusions Muscles of both the suprahyoid and the longitudinal pharyngeal muscle groups are active in swallowing, and both swallowing exercises effectively target muscles elevating the hyolaryngeal complex. mfMRI is useful in testing swallowing muscle function. PMID:22995662

Columbia SMA Project: A Randomized, Control Trial of the Effects of Exercise on Motor Function and Strength in Patients with Spinal Muscular Atrophy (SMA)

DTIC Science & Technology

2012-06-01

Reference values of maximum isometric muscle force obtained in 270 children aged 4-16 years by hand-held dynamometry. Neuromuscul Disord. 2001;11(5...evaluation of specific muscle groups responsible for fatigue-related changes. Since fiber type proportion is determined by its innervation, evaluating muscle ... fiber output provides down-stream information about the integrity of the motor neuron. Objective To determine the association between muscle

Comparison of Two Different Modes of Active Recovery on Muscles Performance after Fatiguing Exercise in Mountain Canoeist and Football Players.

PubMed

Mika, Anna; Oleksy, Łukasz; Kielnar, Renata; Wodka-Natkaniec, Ewa; Twardowska, Magdalena; Kamiński, Kamil; Małek, Zbigniew

2016-01-01

The aim of this study is to assess if the application of different methods of active recovery (working the same or different muscle groups from those which were active during fatiguing exercise) results in significant differences in muscle performance and if the efficiency of the active recovery method is dependent upon the specific sport activity (training loads). A parallel group non-blinded trial with repeated measurements. Thirteen mountain canoeists and twelve football players participated in this study. Measurements of the bioelectrical activity, torque, work and power of the vastus lateralis oblique, vastus medialis oblique, and rectus femoris muscles were performed during isokinetic tests at a velocity of 90°/s. Active legs recovery in both groups was effective in reducing fatigue from evaluated muscles, where a significant decrease in fatigue index was observed. The muscles peak torque, work and power parameters did not change significantly after both modes of active recovery, but in both groups significant decrease was seen after passive recovery. We suggest that 20 minutes of post-exercise active recovery involving the same muscles that were active during the fatiguing exercise is more effective in fatigue recovery than active exercise using the muscles that were not involved in the exercise. Active arm exercises were less effective in both groups which indicates a lack of a relationship between the different training regimens and the part of the body which is principally used during training.

Comparison of Two Different Modes of Active Recovery on Muscles Performance after Fatiguing Exercise in Mountain Canoeist and Football Players

PubMed Central

Mika, Anna; Oleksy, Łukasz; Kielnar, Renata; Wodka-Natkaniec, Ewa; Twardowska, Magdalena; Kamiński, Kamil; Małek, Zbigniew

2016-01-01

Background The aim of this study is to assess if the application of different methods of active recovery (working the same or different muscle groups from those which were active during fatiguing exercise) results in significant differences in muscle performance and if the efficiency of the active recovery method is dependent upon the specific sport activity (training loads). Design A parallel group non-blinded trial with repeated measurements. Methods Thirteen mountain canoeists and twelve football players participated in this study. Measurements of the bioelectrical activity, torque, work and power of the vastus lateralis oblique, vastus medialis oblique, and rectus femoris muscles were performed during isokinetic tests at a velocity of 90°/s. Results Active legs recovery in both groups was effective in reducing fatigue from evaluated muscles, where a significant decrease in fatigue index was observed. The muscles peak torque, work and power parameters did not change significantly after both modes of active recovery, but in both groups significant decrease was seen after passive recovery. Conclusions We suggest that 20 minutes of post-exercise active recovery involving the same muscles that were active during the fatiguing exercise is more effective in fatigue recovery than active exercise using the muscles that were not involved in the exercise. Active arm exercises were less effective in both groups which indicates a lack of a relationship between the different training regimens and the part of the body which is principally used during training. PMID:27706260

Pressure-flow specificity of inspiratory muscle training.

PubMed

Tzelepis, G E; Vega, D L; Cohen, M E; Fulambarker, A M; Patel, K K; McCool, F D

1994-08-01

The inspiratory muscles (IM) can be trained by having a subject breathe through inspiratory resistive loads or by use of unloaded hyperpnea. These disparate training protocols are characterized by high inspiratory pressure (force) or high inspiratory flow (velocity), respectively. We tested the hypothesis that the posttraining improvements in IM pressure or flow performance are specific to training protocols in a way that is similar to force-velocity specificity of skeletal muscle training. IM training was accomplished in 15 normal subjects by use of three protocols: high inspiratory pressure-no flow (group A, n = 5), low inspiratory pressure-high flow (group B, n = 5), and intermediate inspiratory pressure and flow (group C, n = 5). A control group (n = 4) did no training. Before and after training, we measured esophageal pressure (Pes) and inspiratory flow (VI) during single maximal inspiratory efforts against a range of external resistances including an occluded airway. Efforts originated below relaxation volume (Vrel), and peak Pes and VI were measured at Vrel. Isovolume maximal Pes-VI plots were constructed to assess maximal inspiratory pressure-flow performance. Group A (pressure training) performed 30 maximal static inspiratory maneuvers at Vrel daily, group B (flow training) performed 30 sets of three maximal inspiratory maneuvers with no added external resistance daily, and group C (intermediate training) performed 30 maximal inspiratory efforts on a midrange external resistance (7 mm ID) daily. Subjects trained 5 days/wk for 6 wk. Data analysis included comparison of posttraining Pes-VI slopes among training groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of mandibular mobilization on electromyographic signals in muscles of mastication and static balance in individuals with temporomandibular disorder: study protocol for a randomized controlled trial

PubMed Central

2013-01-01

Background The stomatognathic system and dysfunction in this system may be related to postural control. The proposal of the present study is to assess the effect of mandibular mobilization in individuals with temporomandibular disorder using surface electromyography of the muscles of mastication and stabilometric variables. Methods/Design A randomized, controlled, blind, clinical trial will be carried out, with the participants divided into three groups: 1) facial massage therapy (control group), 2) nonspecific mandibular mobilization and 3) specific mandibular mobilization. All groups will be assessed before and after treatment using the Research Diagnostic Criteria for Temporomandibular Disorders, surface electromyography of the masseter and temporal muscles and stabilometry. This study is registered with the Brazilian Registry of Clinical Trials (RBR9x8ssz). Discussion A large number of studies have employed surface electromyography to investigate the function/dysfunction of the muscles of mastication and associations with signs and symptoms of temporomandibular disorders. However, it has not yet been determined whether stabilometric variables offer adequate reliability in patients with this disorder. The results of the proposed study will help determine whether specific and/or nonspecific mandibular mobilization exerts an effect on the muscles of mastication and postural control. Moreover, if an effect is detected, the methodology defined in the proposed study will allow identifying whether the effect is local (found only in the muscles of mastication), global (found only in postural control) or generalized. PMID:24083628

[INVITED] Non-intrusive optical imaging of face to probe physiological traits in Autism Spectrum Disorder

NASA Astrophysics Data System (ADS)

Samad, Manar D.; Bobzien, Jonna L.; Harrington, John W.; Iftekharuddin, Khan M.

2016-03-01

Autism Spectrum Disorders (ASD) can impair non-verbal communication including the variety and extent of facial expressions in social and interpersonal communication. These impairments may appear as differential traits in the physiology of facial muscles of an individual with ASD when compared to a typically developing individual. The differential traits in the facial expressions as shown by facial muscle-specific changes (also known as 'facial oddity' for subjects with ASD) may be measured visually. However, this mode of measurement may not discern the subtlety in facial oddity distinctive to ASD. Earlier studies have used intrusive electrophysiological sensors on the facial skin to gauge facial muscle actions from quantitative physiological data. This study demonstrates, for the first time in the literature, novel quantitative measures for facial oddity recognition using non-intrusive facial imaging sensors such as video and 3D optical cameras. An Institutional Review Board (IRB) approved that pilot study has been conducted on a group of individuals consisting of eight participants with ASD and eight typically developing participants in a control group to capture their facial images in response to visual stimuli. The proposed computational techniques and statistical analyses reveal higher mean of actions in the facial muscles of the ASD group versus the control group. The facial muscle-specific evaluation reveals intense yet asymmetric facial responses as facial oddity in participants with ASD. This finding about the facial oddity may objectively define measurable differential markers in the facial expressions of individuals with ASD.

Different Muscle Action Training Protocols on Quadriceps-Hamstrings Neuromuscular Adaptations.

PubMed

Ruas, Cassio V; Brown, Lee E; Lima, Camila D; Gregory Haff, G; Pinto, Ronei S

2018-05-01

The aim of this study was to compare three specific concentric and eccentric muscle action training protocols on quadriceps-hamstrings neuromuscular adaptations. Forty male volunteers performed 6 weeks of training (two sessions/week) of their dominant and non-dominant legs on an isokinetic dynamometer. They were randomly assigned to one of four groups; concentric quadriceps and concentric hamstrings (CON/CON, n=10), eccentric quadriceps and eccentric hamstrings (ECC/ECC, n=10), concentric quadriceps and eccentric hamstrings (CON/ECC, n=10), or no training (CTRL, n=10). Intensity of training was increased every week by decreasing the angular velocity for concentric and increasing it for eccentric groups in 30°/s increments. Volume of training was increased by adding one set every week. Dominant leg quadriceps and hamstrings muscle thickness, muscle quality, muscle activation, muscle coactivation, and electromechanical delay were tested before and after training. Results revealed that all training groups similarly increased MT of quadriceps and hamstrings compared to control (p<0.05). However, CON/ECC and ECC/ECC training elicited a greater magnitude of change. There were no significant differences between groups for all other neuromuscular variables (p>0.05). These findings suggest that different short-term muscle action isokinetic training protocols elicit similar muscle size increases in hamstrings and quadriceps, but not for other neuromuscular variables. Nevertheless, effect sizes indicate that CON/ECC and ECC/ECC may elicit the greatest magnitude of change in muscle hypertrophy. © Georg Thieme Verlag KG Stuttgart · New York.

Diffusion tensor imaging of the human calf: Variation of inter- and intramuscle-specific diffusion parameters.

PubMed

Schlaffke, Lara; Rehmann, Robert; Froeling, Martijn; Kley, Rudolf; Tegenthoff, Martin; Vorgerd, Matthias; Schmidt-Wilcke, Tobias

2017-10-01

To investigate to what extent inter- and intramuscular variations of diffusion parameters of human calf muscles can be explained by age, gender, muscle location, and body mass index (BMI) in a specific age group (20-35 years). Whole calf muscles of 18 healthy volunteers were evaluated. Magnetic resonance imaging (MRI) was performed using a 3T scanner and a 16-channel Torso XL coil. Diffusion-weighted images were acquired to perform fiber tractography and diffusion tensor imaging (DTI) analysis for each muscle of both legs. Fiber tractography was used to separate seven lower leg muscles. Associations between DTI parameters and confounds were evaluated. All muscles were additionally separated in seven identical segments along the z-axis to evaluate intramuscular differences in diffusion parameters. Fractional anisotropy (FA) and mean diffusivity (MD) were obtained for each muscle with low standard deviations (SDs) (SD FA : 0.01-0.02; SD MD : 0.07-0.14(10 -3 )). We found significant differences in FA values of the tibialis anterior muscle (AT) and extensor digitorum longus (EDL) muscles between men and women for whole muscle FA (two-sample t-tests; AT: P = 0.0014; EDL: P = 0.0004). We showed significant intramuscular differences in diffusion parameters between adjacent segments in most calf muscles (P < 0.001). Whereas muscle insertions showed higher (SD 0.03-0.06) than muscle bellies (SD 0.01-0.03), no relationships between FA or MD with age or BMI were found. Inter- and intramuscular variations in diffusion parameters of the calf were shown, which are not related to age or BMI in this age group. Differences between muscle belly and insertion should be considered when interpreting datasets not including whole muscles. 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1137-1148. © 2017 International Society for Magnetic Resonance in Medicine.

Effects of a vitamin D and leucine-enriched whey protein nutritional supplement on measures of sarcopenia in older adults, the PROVIDE study: a randomized, double-blind, placebo-controlled trial.

PubMed

Bauer, Jürgen M; Verlaan, Sjors; Bautmans, Ivan; Brandt, Kirsten; Donini, Lorenzo M; Maggio, Marcello; McMurdo, Marion E T; Mets, Tony; Seal, Chris; Wijers, Sander L; Ceda, Gian Paolo; De Vito, Giuseppe; Donders, Gilbert; Drey, Michael; Greig, Carolyn; Holmbäck, Ulf; Narici, Marco; McPhee, Jamie; Poggiogalle, Eleonora; Power, Dermot; Scafoglieri, Aldo; Schultz, Ralf; Sieber, Cornel C; Cederholm, Tommy

2015-09-01

Age-related losses of muscle mass, strength, and function (sarcopenia) pose significant threats to physical performance, independence, and quality of life. Nutritional supplementation could positively influence aspects of sarcopenia and thereby prevent mobility disability. To test the hypothesis that a specific oral nutritional supplement can result in improvements in measures of sarcopenia. A multicenter, randomized, controlled, double-blind, 2 parallel-group trial among 380 sarcopenic primarily independent-living older adults with Short Physical Performance Battery (SPPB; 0-12) scores between 4 and 9, and a low skeletal muscle mass index. The active group (n = 184) received a vitamin D and leucine-enriched whey protein nutritional supplement to consume twice daily for 13 weeks. The control group (n = 196) received an iso-caloric control product to consume twice daily for 13 weeks. Primary outcomes of handgrip strength and SPPB score, and secondary outcomes of chair-stand test, gait speed, balance score, and appendicular muscle mass (by DXA) were measured at baseline, week 7, and week 13 of the intervention. Handgrip strength and SPPB improved in both groups without significant between-group differences. The active group improved more in the chair-stand test compared with the control group, between-group effect (95% confidence interval): -1.01 seconds (-1.77 to -0.19), P = .018. The active group gained more appendicular muscle mass than the control group, between-group effect: 0.17 kg (0.004-0.338), P = .045. This 13-week intervention of a vitamin D and leucine-enriched whey protein oral nutritional supplement resulted in improvements in muscle mass and lower-extremity function among sarcopenic older adults. This study shows proof-of-principle that specific nutritional supplementation alone might benefit geriatric patients, especially relevant for those who are unable to exercise. These results warrant further investigations into the role of a specific nutritional supplement as part of a multimodal approach to prevent adverse outcomes among older adults at risk for disability. Copyright © 2015 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

Asymmetry of neck motion and activation of the cervical paraspinal muscles during prone neck extension in subjects with unilateral posterior neck pain.

PubMed

Park, Kyue-Nam; Kwon, Oh-Yun; Kim, Su-Jung; Kim, Si-Hyun

2017-01-01

Although unilateral posterior neck pain (UPNP) is more prevalent than central neck pain, little is known about how UPNP affects neck motion and the muscle activation pattern during prone neck extension. To investigate whether deviation in neck motion and asymmetry of activation of the bilateral cervical paraspinal muscles occur during prone neck extension in subjects with UPNP compared to subjects without UPNP. This study recruited 20 subjects with UPNP and 20 age- and sex-matched control subjects without such pain. Neck motion and muscle onset time during prone neck extension were measured using a three-dimensional motion-analysis system and surface electromyography. The deviation during prone neck extension was greater in the UPNP group than in the controls (p < 0.05). Compared with the controls, cervical extensor muscle activation in the UPNP group was significantly delayed on the painful side during prone neck extension (p < 0.05). Subjects with UPNP showed greater asymmetry of neck motion and muscle activation during prone neck extension compared with the controls. This suggests that UPNP has specific effects on neck motion asymmetry and the functions of the cervical extensors, triggering a need for specific evaluation and exercises in the management of patients with UPNP.

Quantitative Skeletal Muscle MRI: Part 2, MR Spectroscopy and T2 Relaxation Time Mapping-Comparison Between Boys With Duchenne Muscular Dystrophy and Healthy Boys.

PubMed

Kim, Hee Kyung; Serai, Suraj; Lindquist, Diana; Merrow, Arnold C; Horn, Paul S; Kim, Dong Hoon; Wong, Brenda L

2015-08-01

The purpose of this study is to validate the use of MR spectroscopy (MRS) in measuring muscular fat and to compare it with T2 maps in differentiating boys with Duchenne muscular dystrophy (DMD) from healthy boys. Forty-two boys with DMD and 31 healthy boys were evaluated with MRI with (1)H-MRS and T2 maps. Grading of muscle fat and edema on conventional images, calculation of fat fractions ([fat / fat] + water) on MRS, and calculation of T2 fat values on T2 maps of the gluteus maximus and vastus lateralis muscles were performed. Group comparisons were made. The 95% reference interval (RI) of fat fraction for the control group was applied and compared with T2 map results. Minimal fat on T1-weighted images was seen in 90.3% (gluteus maximus) and 71.0% (vastus lateralis) of healthy boys, versus 33.3% (gluteus maximus) and 52.4% (vastus lateralis) of boys with DMD. Muscle edema was seen in none of the healthy boys versus 52.4% (gluteus maximus) and 57.1% (vastus lateralis) of the boys with DMD. Fat fractions were higher in the DMD group (52.7%, gluteus maximus; 27.3%, vastus lateralis) than in the control group (12.8%, gluteus maximus; 13.7%, vastus lateralis) (p < 0.001). The 95% RI for gluteus maximus (38.7%) resulted in 61.9% sensitivity and 100% specificity for differentiating boys with DMD from healthy boys, whereas the value for vastus lateralis (17.8%) resulted in 76.2% sensitivity and 100% specificity; both had lower accuracy than did T2 maps (100% sensitivity and specificity). There was a positive correlation between T2 fat values and fat fractions (p < 0.0001). In differentiation of the two groups, T2 maps were more accurate than MRS. Fat fractions can underestimate the actual amount of fat because of coexisting muscle edema in DMD.

Deregulation of the Protocadherin Gene FAT1 Alters Muscle Shapes: Implications for the Pathogenesis of Facioscapulohumeral Dystrophy

PubMed Central

Caruso, Nathalie; Herberth, Balàzs; Bartoli, Marc; Puppo, Francesca; Dumonceaux, Julie; Zimmermann, Angela; Denadai, Simon; Lebossé, Marie; Roche, Stephane; Geng, Linda; Magdinier, Frederique; Attarian, Shahram; Bernard, Rafaelle; Maina, Flavio; Levy, Nicolas; Helmbacher, Françoise

2013-01-01

Generation of skeletal muscles with forms adapted to their function is essential for normal movement. Muscle shape is patterned by the coordinated polarity of collectively migrating myoblasts. Constitutive inactivation of the protocadherin gene Fat1 uncoupled individual myoblast polarity within chains, altering the shape of selective groups of muscles in the shoulder and face. These shape abnormalities were followed by early onset regionalised muscle defects in adult Fat1-deficient mice. Tissue-specific ablation of Fat1 driven by Pax3-cre reproduced muscle shape defects in limb but not face muscles, indicating a cell-autonomous contribution of Fat1 in migrating muscle precursors. Strikingly, the topography of muscle abnormalities caused by Fat1 loss-of-function resembles that of human patients with facioscapulohumeral dystrophy (FSHD). FAT1 lies near the critical locus involved in causing FSHD, and Fat1 mutant mice also show retinal vasculopathy, mimicking another symptom of FSHD, and showed abnormal inner ear patterning, predictive of deafness, reminiscent of another burden of FSHD. Muscle-specific reduction of FAT1 expression and promoter silencing was observed in foetal FSHD1 cases. CGH array-based studies identified deletion polymorphisms within a putative regulatory enhancer of FAT1, predictive of tissue-specific depletion of FAT1 expression, which preferentially segregate with FSHD. Our study identifies FAT1 as a critical determinant of muscle form, misregulation of which associates with FSHD. PMID:23785297

Muscle coordination during breaststroke swimming: Comparison between elite swimmers and beginners.

PubMed

Vaz, João R; Olstad, Bjørn Harald; Cabri, Jan; Kjendlie, Per-Ludvik; Pezarat-Correia, Pedro; Hug, François

2016-10-01

The present study aimed to compare muscle coordination strategies of the upper and lower limb muscles between beginners and elite breaststroke swimmers. Surface electromyography (EMG) of eight muscles was recorded in 16 swimmers (8 elite, 8 beginners) during a 25 m swimming breaststroke at 100% of maximal effort. A decomposition algorithm was used to identify the muscle synergies that represent the temporal and spatial organisation of muscle coordination. Between-groups indices of similarity and lag times were calculated. Individual muscle patterns were moderately to highly similar between groups (between-group indices range: 0.61 to 0.84). Significant differences were found in terms of lag time for pectoralis major (P < 0.05), biceps brachii, rectus femoris and tibialis anterior (P < 0.01), indicating an earlier activation for these muscles in beginners compared to elites (range: -13.2 to -3.8% of the swimming cycle). Three muscle synergies were identified for both beginners and elites. Although their composition was similar between populations, the third synergy exhibited a high within-group variability. Moderate to high indices of similarity were found for the shape of synergy activation coefficients (range: 0.63 to 0.88) but there was a significant backward shift (-8.4% of the swimming cycle) in synergy #2 for beginners compared to elites. This time shift suggested differences in the global arm-to-leg coordination. These results indicate that the synergistic organisation of muscle coordination during breaststroke swimming is not profoundly affected by expertise. However, specific timing adjustments were observed between lower and upper limbs.

Intermittent Resistance Training at Moderate Altitude: Effects on the Force-Velocity Relationship, Isometric Strength and Muscle Architecture

PubMed Central

Morales-Artacho, Antonio J.; Padial, Paulino; García-Ramos, Amador; Pérez-Castilla, Alejandro; Argüelles-Cienfuegos, Javier; De la Fuente, Blanca; Feriche, Belén

2018-01-01

Intermittent hypoxic resistance training (IHRT) may help to maximize the adaptations following resistance training, although conflicting evidence is available. The aim of this study was to explore the influence of moderate altitude on the functional, neural and muscle architecture responses of the quadriceps muscles following a power-oriented IHRT intervention. Twenty-four active males completed two 4-week consecutive training blocks comprising general strengthening exercises (weeks 1–4) and power-oriented resistance training (weeks 5–8). Training sessions were conducted twice a week at moderate altitude (2320 m; IHRT, n = 13) or normoxia (690 m; NT, n = 11). Training intensity during the second training block was set to the individual load corresponding to a barbell mean propulsive velocity of 1 m·s−1. Pre-post assessments, performed under normoxic conditions, comprised quadriceps muscle architecture (thickness, pennation angle and fascicle length), isometric maximal (MVF) and explosive strength, and voluntary muscle activation. Dynamic strength performance was assessed through the force-velocity relationship (F0, V0, P0) and a repeated CMJ test (CMJ15MP). Region-specific muscle thickness changes were observed in both training groups (p < 0.001, ηG2 = 0.02). A small opposite trend in pennation angle changes was observed (ES [90% CI]: −0.33 [−0.65, −0.01] vs. 0.11 [−0.44, 0.6], in the IHRT and NT group, respectively; p = 0.094, ηG2 = 0.02). Both training groups showed similar improvements in MVF (ES: 0.38 [0.20, 0.56] vs. 0.55 [0.29, 0.80], in the IHRT and NT group, respectively; p = 0.645, ηG2 < 0.01), F0 (ES: 0.41 [−0.03, 0.85] vs. 0.52 [0.04, 0.99], in the IHRT and NT group, respectively; p = 0.569, ηG2 < 0.01) and P0 (ES: 0.53 [0.07, 0.98] vs. 0.19 [−0.06, 0.44], in the IHRT and NT group, respectively; p = 0.320, ηG2 < 0.01). No meaningful changes in explosive strength performance were observed. In conclusion, contrary to earlier adverse associations between altitude and resistance-training muscle adaptations, similar anatomical and functional muscle strength responses can be achieved in both environmental conditions. The observed region-specific muscle thickness changes may encourage further research on the potential influence of IHRT on muscle morphological changes. PMID:29882549

Precision of MRI-based body composition measurements of postmenopausal women

PubMed Central

Romu, Thobias; Thorell, Sofia; Lindblom, Hanna; Berin, Emilia; Holm, Anna-Clara Spetz; Åstrand, Lotta Lindh; Karlsson, Anette; Borga, Magnus; Hammar, Mats; Leinhard, Olof Dahlqvist

2018-01-01

Objectives To determine precision of magnetic resonance imaging (MRI) based fat and muscle quantification in a group of postmenopausal women. Furthermore, to extend the method to individual muscles relevant to upper-body exercise. Materials and methods This was a sub-study to a randomized control trial investigating effects of resistance training to decrease hot flushes in postmenopausal women. Thirty-six women were included, mean age 56 ± 6 years. Each subject was scanned twice with a 3.0T MR-scanner using a whole-body Dixon protocol. Water and fat images were calculated using a 6-peak lipid model including R2*-correction. Body composition analyses were performed to measure visceral and subcutaneous fat volumes, lean volumes and muscle fat infiltration (MFI) of the muscle groups’ thigh muscles, lower leg muscles, and abdominal muscles, as well as the three individual muscles pectoralis, latissimus, and rhomboideus. Analysis was performed using a multi-atlas, calibrated water-fat separated quantification method. Liver-fat was measured as average proton density fat-fraction (PDFF) of three regions-of-interest. Precision was determined with Bland-Altman analysis, repeatability, and coefficient of variation. Results All of the 36 included women were successfully scanned and analysed. The coefficient of variation was 1.1% to 1.5% for abdominal fat compartments (visceral and subcutaneous), 0.8% to 1.9% for volumes of muscle groups (thigh, lower leg, and abdomen), and 2.3% to 7.0% for individual muscle volumes (pectoralis, latissimus, and rhomboideus). Limits of agreement for MFI was within ± 2.06% for muscle groups and within ± 5.13% for individual muscles. The limits of agreement for liver PDFF was within ± 1.9%. Conclusion Whole-body Dixon MRI could characterize a range of different fat and muscle compartments with high precision, including individual muscles, in the study-group of postmenopausal women. The inclusion of individual muscles, calculated from the same scan, enables analysis for specific intervention programs and studies. PMID:29415060

Muscle injury is the principal injury type and hamstring muscle injury is the first injury diagnosis during top-level international athletics championships between 2007 and 2015.

PubMed

Edouard, Pascal; Branco, Pedro; Alonso, Juan-Manuel

2016-05-01

During top-level international athletics championships, muscle injuries are frequent. To analyse the incidence and characteristics of muscle injuries and hamstring muscle injuries (hamstring injuries) occurring during top-level international athletics championships. During 16 international championships held between 2007 and 2015, national medical team and local organising committee physicians reported daily all injuries on a standardised injury report form. Only muscle injuries (muscle tears and muscle cramps) and hamstring injuries have been analysed. 40.9% of all recorded injuries (n=720) were muscle injuries, with 57.5% of them resulting in time loss. The overall incidence of muscle injuries was higher in male athletes than female athletes (51.9±6.0 vs 30.3±5.0 injuries per 1000 registered athletes, respectively; RR=1.71; 95% CI 1.45 to 2.01). Muscle injuries mainly affected the thigh (52.9%) and lower leg (20.1%), and were mostly caused by overuse with sudden onset (38.2%) and non-contact trauma (24.6%). Muscle injury risk varied according to the event groups. Hamstring injuries represented 17.1% of all injuries, with a higher risk in male compared to female athletes (22.4±3.4 vs 11.5±2.6 injuries per 1000 registered athletes, respectively; RR=1.94; 95% CI 1.42 to 2.66). During international athletics championships, muscle injury is the principal type of injury, and among those, the hamstring is the most commonly affected, with a two times higher risk in male than female athletes. Athletes in explosive power events, male athletes and older male athletes, in specific were more at risk of muscle injuries and hamstring injuries. Injury prevention strategies should be sex-specific. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Resistance Training Enhances Skeletal Muscle Innervation Without Modifying the Number of Satellite Cells or their Myofiber Association in Obese Older Adults

PubMed Central

Messi, María Laura; Li, Tao; Wang, Zhong-Min; Marsh, Anthony P.; Nicklas, Barbara

2016-01-01

Studies in humans and animal models provide compelling evidence for age-related skeletal muscle denervation, which may contribute to muscle fiber atrophy and loss. Skeletal muscle denervation seems relentless; however, long-term, high-intensity physical activity appears to promote muscle reinnervation. Whether 5-month resistance training (RT) enhances skeletal muscle innervation in obese older adults is unknown. This study found that neural cell-adhesion molecule, NCAM+ muscle area decreased with RT and was inversely correlated with muscle strength. NCAM1 and RUNX1 gene transcripts significantly decreased with the intervention. Type I and type II fiber grouping in the vastus lateralis did not change significantly but increases in leg press and knee extensor strength inversely correlated with type I, but not with type II, fiber grouping. RT did not modify the total number of satellite cells, their number per area, or the number associated with specific fiber subtypes or innervated/denervated fibers. Our results suggest that RT has a beneficial impact on skeletal innervation, even when started late in life by sedentary obese older adults. PMID:26447161

Short-term effect of local muscle vibration treatment versus sham therapy on upper limb in chronic post-stroke patients: a randomized controlled trial.

PubMed

Costantino, Cosimo; Galuppo, Laura; Romiti, Davide

2017-02-01

In recent years, local muscle vibration received considerable attention as a useful method for muscle stimulation in clinical therapy. Some studies described specific vibration training protocol, and few of them were conducted on post-stroke patients. Therefore there is a general uncertainty regarding the vibrations protocol. The aim of this study was to evaluate the effects of local muscle high frequency mechano-acoustic vibratory treatment on grip muscle strength, muscle tonus, disability and pain in post-stroke individuals with upper limb spasticity. Single-blind randomized controlled trial. Outpatient rehabilitation center. Thirty-two chronic poststroke patients with upper-limb spasticity: 21 males, 11 females, mean age 61.59 years ±15.50, time passed from stroke 37.78±17.72 months. The protocol treatment consisted of the application of local muscle vibration, set to a frequency of 300 Hz, for 30 minutes 3 times per week, for 12 sessions, applied to the skin covering the venter of triceps brachii and extensor carpi radialis longus and brevis muscles during voluntary isometric contraction. All participants were randomized in two groups: group A treated with vibration protocol; group B with sham therapy. All participants were evaluated before and after 4-week treatment with Hand Grip Strength Test, Modified Ashworth Scale, QuickDASH score, FIM scale, Fugl-Meyer Assessment, Jebsen-Taylor Hand Function Test and Verbal Numerical Rating Scale of pain. Outcomes between groups was compared using a repeated-measures ANOVA. Over 4 weeks, the values recorded in group A when compared to group B demonstrated statistically significant improvement in grip muscle strength, pain and quality of life and decrease of spasticity; P-values were <0.05 in all tested parameters. Rehabilitation treatment with local muscle high frequency (300 Hz) vibration for 30 minutes, 3 times a week for 4 weeks, could significantly improve muscle strength and decrease muscle tonus, disability and pain in upper limb of hemiplegic post-stroke patients. Local muscle vibration treatment might be an additional and safe tool in the management of chronic poststroke patients, granted its high therapeutic efficiency, limited cost and short and repeatable protocol of use.

[Benefits of Decumanum Phlebodium intake on the muscle damage in the response to intense physical exercise in sedentary subjects].

PubMed

Vargas Corzo, M C; Aguilar Cordero, M J; de Teresa Galván, C; Segura Millán, D; Miranda Leon, M T; Castillo Rueda, G; Guisado Barrilao, R

2014-06-01

Intense physical exercise provoke muscle damage, that in sedentary people can increase cardiovascular risk. Phlebodium decumanum (PD) has shown to have immunomodulator effects in models of moderate intense physical activities in well conditioned groups. To evaluate the PD effects during eccentric exercise, as a model of muscle inflammation protocol, on a sedentary population with cardiovascular risk. This is an experimental, double-blind, multigroup randomized study. Experimental Group 1 (n = 17)received PD, 9 doses of 400 mg (total amount 3.6 g) every 8 hours during 3 days, and Control Group 2 (n = 16)received a placebo. All the subjects performed two treadmill ergoespirometry tests: first, a modified Bruce protocol to discard ischemic responses during exercise and to evaluate VO2max before the experimental phase;and second, with an eccentric protocol (14% descending ramp test) during 10 minutes in stable state at 70-80%VO2max, as experimental inflammatory protocol.We compared intra and inter groups to evaluate differences in the pre and post-test differences results on blood muscle damage variables. The study shown statistically significant differences in all pre-post intra-groups results in muscle damage variables (CK, LDH and Myoglobin, but not in Cardiac Troponin), and in functional lower-limb test (SJand CMJ). The comparison of inter-group results shown less muscle damage and less functional lower-limb deterioration in Group 1 compared with Control group, with statistical significance in both cases. Differences in handgrip dynamometry were no statistically significant. The eccentric exercise protocol in that study has proven to be a good model to induce muscle and functional damage in sedentary people. Short PD treatment has shown to reduce muscle and functional acute damages compared with placebo control group in this specific population. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Temporal patterns of the trunk muscles remain altered in a low back-injured population despite subjective reports of recovery.

PubMed

Moreside, Janice M; Quirk, D Adam; Hubley-Kozey, Cheryl L

2014-04-01

To compare temporal activation patterns from 24 abdominal and lumbar muscles between healthy subjects and those who reported recovery from recent low back injury (LBI). Cross-sectional comparative study. University neuromuscular function laboratory. Healthy adult volunteers (N=81; 30 LBI, 51 asymptomatic subjects). Trunk muscle electromyographic activity was collected during 2 difficulty levels of a supine trunk stability test aimed at challenging lumbopelvic control. Principal component (PC) analysis was applied to determine differences in temporal and/or amplitude electromyographic patterns between groups. Mixed-model analyses of variance were performed on PC scores that explained more than 89% of the variance (α=.05). Four PCs explained 89% and 96% of the variance for the abdominal and back muscles, respectively, with both muscle groups having similar shapes in the first 3 PCs. Significant interactions or group main effects were found for all PC scores except PC4 for the back extensors. Overall activation amplitudes for both the abdominal and back muscles (PC1 scores) were significantly (P<.05) higher for the LBI group, with both abdominal and back muscles of the LBI group demonstrating an increased response to the leg-loading phase (PC2 scores) compared with the asymptomatic group. Differences were also found between groups in their preparatory activity (PC3 scores), with the LBI group having a higher early relative amplitude of abdominal and back extensor activity. Despite perceived readiness to return to work and low pain scores, muscle activation patterns remained altered in this LBI group, including reduced synergistic coactivation and increased overall amplitudes as well as greater relative amplitude differences during specific phases of the movement. Electromyographic measures provide objective information to help guide therapy and may assist with determining the level of healing and return-to-work readiness after an LBI. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Differences in feedforward trunk muscle activity in subgroups of patients with mechanical low back pain.

PubMed

Silfies, Sheri P; Mehta, Rupal; Smith, Sue S; Karduna, Andrew R

2009-07-01

To investigate alterations in trunk muscle timing patterns in subgroups of patients with mechanical low back pain (MLBP). Our hypothesis was that subjects with MLBP would demonstrate delayed muscle onset and have fewer muscles functioning in a feedforward manner than the control group. We further hypothesized that we would find differences between subgroups of our patients with MLBP, grouped according to diagnosis (segmental instability and noninstability). Case-control. Laboratory. Forty-three patients with chronic MLBP (25 instability, 18 noninstability) and 39 asymptomatic controls. Not applicable. Surface electromyography was used to measure onset time of 10 trunk muscles during a self-perturbation task. Trunk muscle onset latency relative to the anterior deltoid was calculated and the number of muscles functioning in feedforward determined. Activation timing patterns (P<.01; eta=.50; 1-beta=.99) and number of muscles functioning in feedforward (P=.02; eta=.30; 1-beta=.83) were statistically different between patients with MLBP and controls. The control group activated the external oblique, lumbar multifidus, and erector spinae muscles in a feedforward manner. The heterogeneous MLBP group did not activate the trunk musculature in feedforward, but responded with significantly delayed activations. MLBP subgroups demonstrated significantly different timing patterns. The noninstability MLBP subgroup activated trunk extensors in a feedforward manner, similar to the control group, but significantly earlier than the instability subgroup. Lack of feedforward activation of selected trunk musculature in patients with MLBP may result in a period of inefficient muscular stabilization. Activation timing was more impaired in the instability than the noninstability MLBP subgroup. Training specifically for recruitment timing may be an important component of the rehabilitation program.

Directing Spinal Cord Plasticity: The Impact of Stretch Therapy on Functional Recovery after Spinal Cord Injury

DTIC Science & Technology

2014-10-01

atrophy. Interestingly, there is a clinical phenomenon that stretching can lead to muscle fiber hypertrophy , but that doesn’t appear to be...specific muscle groups) on functional recovery after spinal cord injury in a rat model. We have undertaken these studies because of an observation we...spinal cord injury, locomotor recovery, physical therapy, muscle stretch, joint range- of-motion, rat. Overall Project Summary: In this, the

Assessment of neuromuscular risk factors for anterior cruciate ligament injury through tensiomyography in male soccer players.

PubMed

Alentorn-Geli, Eduard; Alvarez-Diaz, Pedro; Ramon, Silvia; Marin, Miguel; Steinbacher, Gilbert; Boffa, Juan José; Cuscó, Xavier; Ballester, Jordi; Cugat, Ramon

2015-09-01

To investigate the role of mechanical and contractile properties of skeletal muscles of the thigh, assessed through tensiomyography (TMG), as risk factors for anterior cruciate ligament (ACL) injury in male soccer players. Male soccer players with confirmed ACL tear included in this study underwent resting TMG assessment of thigh muscles of the uninjured side. The same values were obtained from a sex-, sports level-matched control group in both sides. The maximal displacement (Dm), delay time (Td), contraction time (Tc), sustained time (Ts), and half-relaxation time (Tr) were obtained for the following muscles in all subjects: vastus medialis (VM), vastus laterals (VL), rectus femoris (RF), semitendinosus (ST), and biceps femoris (BF). TMG values of the uninjured side in ACL-injured group were compared to mean values between both sides in the control subjects. There were 40 ACL-injured and 38 control individuals. The vast majority of TMG parameters were higher in the uninjured side of ACL-injured individuals compared to the control group. The VL-Tr, RF-Tc, RF-Ts, RF-Tr, and BF-Dm values were significantly higher in the uninjured side compared to the control group. Quadriceps muscles demonstrated more significant between-group differences than hamstring muscles. Specifically, RF was the muscle where most significant between-group differences were found. Resistance to fatigue and muscle stiffness in the hamstring muscles may be risk factors for ACL injury in male soccer players. In addition, a predominant impairment in TMG characteristics of the quadriceps over hamstrings may indicate an altered muscular co-contraction (imbalance) between both muscle groups, which might be another risk factor for ACL injury in this population. These findings should be taken into account when screening athletes at high risk of ACL injury and also to design adequate prevention programs for ACL injury in male soccer players.

The analgesic effect of photobiomodulation therapy (830 nm) on the masticatory muscles: a randomized, double-blind study.

PubMed

Costa, Sabrina Araújo Pinho; Florezi, Giovanna Piacenza; Artes, Gisele Ebling; Costa, Jessica Ribeiro da; Gallo, Rosane Tronchin; Freitas, Patricia Moreira de; Witzel, Andrea Lusvarghi

2017-12-18

This study assesses the efficacy of photobiomodulation therapy (830 nm) for myalgia treatment of masticatory muscles. Sixty patients with muscular myalgia were selected and randomly allocated into 2 groups (n=30): Group A comprised patients given a placebo (control), and Group B consisted of those undergoing photobiomodulation therapy (PBMT). PBMT and placebo were applied bilaterally to specific points on the masseter and temporal muscles. Referred pain elicited by palpation and maximum mouth opening were measured before (EV1) and after (EV2) the treatments. The data were analyzed using statistical tests, considering a significance level of 5%. No significant differences in range were observed for active or passive mouth opening (p ≥ 0.05). Comparing the final outcomes (EV1-EV2) of both treatments, statistical significance was verified for total pain in the right masseter muscle (p = 0.001) and total pain (p = 0.005). In EV2, significant differences in pain reported with palpation were found between Groups A and B for the following: left posterior temporal muscle (p = 0.025), left superior masseter muscle (p = 0.036), inferior masseter muscle (p = 0.021), total pain (left side) (p = 0.009), total masseter muscle (left side) (p = 0.014), total temporal (left side) (p = 0.024), and total pain (p = 0.035). We concluded that PBMT (830 nm) reduces pain in algic points, but does not influence the extent of mouth opening in patients with myalgia.

An aerobic walking programme versus muscle strengthening programme for chronic low back pain: a randomized controlled trial.

PubMed

Shnayderman, Ilana; Katz-Leurer, Michal

2013-03-01

To assess the effect of aerobic walking training as compared to active training, which includes muscle strengthening, on functional abilities among patients with chronic low back pain. Randomized controlled clinical trial with blind assessors. Outpatient clinic. Fifty-two sedentary patients, aged 18-65 years with chronic low back pain. Patients who were post surgery, post trauma, with cardiovascular problems, and with oncological disease were excluded. Experimental 'walking' group: moderate intense treadmill walking; control 'exercise' group: specific low back exercise; both, twice a week for six weeks. Six-minute walking test, Fear-Avoidance Belief Questionnaire, back and abdomen muscle endurance tests, Oswestry Disability Questionnaire, Low Back Pain Functional Scale (LBPFS). Significant improvements were noted in all outcome measures in both groups with non-significant difference between groups. The mean distance in metres covered during 6 minutes increased by 70.7 (95% confidence interval (CI) 12.3-127.7) in the 'walking' group and by 43.8 (95% CI 19.6-68.0) in the 'exercise' group. The trunk flexor endurance test showed significant improvement in both groups, increasing by 0.6 (95% CI 0.0-1.1) in the 'walking' group and by 1.1 (95% CI 0.3-1.8) in the 'exercise' group. A six-week walk training programme was as effective as six weeks of specific strengthening exercises programme for the low back.

Zebrafish models flex their muscles to shed light on muscular dystrophies.

PubMed

Berger, Joachim; Currie, Peter D

2012-11-01

Muscular dystrophies are a group of genetic disorders that specifically affect skeletal muscle and are characterized by progressive muscle degeneration and weakening. To develop therapies and treatments for these diseases, a better understanding of the molecular basis of muscular dystrophies is required. Thus, identification of causative genes mutated in specific disorders and the study of relevant animal models are imperative. Zebrafish genetic models of human muscle disorders often closely resemble disease pathogenesis, and the optical clarity of zebrafish embryos and larvae enables visualization of dynamic molecular processes in vivo. As an adjunct tool, morpholino studies provide insight into the molecular function of genes and allow rapid assessment of candidate genes for human muscular dystrophies. This unique set of attributes makes the zebrafish model system particularly valuable for the study of muscle diseases. This review discusses how recent research using zebrafish has shed light on the pathological basis of muscular dystrophies, with particular focus on the muscle cell membrane and the linkage between the myofibre cytoskeleton and the extracellular matrix.

Postinjury Exercise and Platelet-Rich Plasma Therapies Improve Skeletal Muscle Healing in Rats But Are Not Synergistic When Combined.

PubMed

Contreras-Muñoz, Paola; Torrella, Joan Ramon; Serres, Xavier; Rizo-Roca, David; De la Varga, Meritxell; Viscor, Ginés; Martínez-Ibáñez, Vicente; Peiró, José Luis; Järvinen, Tero A H; Rodas, Gil; Marotta, Mario

2017-07-01

Skeletal muscle injuries are the most common sports-related injury and a major concern in sports medicine. The effect of platelet-rich plasma (PRP) injections on muscle healing is still poorly understood, and current data are inconclusive. To evaluate the effects of an ultrasound-guided intramuscular PRP injection, administered 24 hours after injury, and/or posttraumatic daily exercise training for 2 weeks on skeletal muscle healing in a recently established rat model of skeletal muscle injury that highly mimics the muscle trauma seen in human athletes. Controlled laboratory study. A total of 40 rats were assigned to 5 groups. Injured rats (medial gastrocnemius injury) received a single PRP injection (PRP group), daily exercise training (Exer group), or a combination of a single PRP injection and daily exercise training (PRP-Exer group). Untreated and intramuscular saline-injected animals were used as controls. Muscle force was determined 2 weeks after muscle injury, and muscles were harvested and evaluated by means of histological assessment and immunofluorescence microscopy. Both PRP (exhibiting 4.8-fold higher platelet concentration than whole blood) and exercise training improved muscle strength (maximum tetanus force, TetF) in approximately 18%, 20%, and 30% of rats in the PRP, PRP-Exer, and Exer groups, respectively. Specific markers of muscle regeneration (developmental myosin heavy chain, dMHC) and scar formation (collagen I) demonstrated the beneficial effect of the tested therapies in accelerating the muscle healing process in rats. PRP and exercise treatments stimulated the growth of newly formed regenerating muscle fibers (1.5-, 2-, and 2.5-fold increase in myofiber cross-sectional area in PRP, PRP-Exer, and Exer groups, respectively) and reduced scar formation in injured skeletal muscle (20%, 34%, and 41% of reduction in PRP, PRP-Exer, and Exer groups, respectively). Exercise-treated muscles (PRP-Exer and Exer groups) had significantly reduced percentage of dMHC-positive regenerating fibers (35% and 47% decrease in dMHC expression, respectively), indicating that exercise therapies accelerated the muscle healing process witnessed by the more rapid replacement of the embryonic-developmental myosin isoform by mature muscle myosin isoforms. Intramuscular PRP injection and, especially, treadmill exercise improve histological outcome and force recovery of the injured skeletal muscle in a rat injury model that imitates sports-related muscle injuries in athletes. However, there was not a synergistic effect when both treatments were combined, suggesting that PRP does not add any beneficial effect to exercise-based therapy in the treatment of injured skeletal muscle. This study demonstrates the efficacy of an early active rehabilitation protocol or single intramuscular PRP injection on muscle recovery. The data also reveal that the outcome of the early active rehabilitation is adversely affected by the PRP injection when the two therapies are combined, and this could explain why PRP therapies have failed in randomized clinical trials where the athletes have adhered to postinjection rehabilitation protocols based on the principle of early, active mobilization.

Whey protein supplementation accelerates satellite cell proliferation during recovery from eccentric exercise.

PubMed

Farup, Jean; Rahbek, Stine Klejs; Knudsen, Inge Skovgaard; de Paoli, Frank; Mackey, Abigail L; Vissing, Kristian

2014-11-01

Human skeletal muscle satellite cells (SCs) are essential for muscle regeneration and remodeling processes in healthy and clinical conditions involving muscle breakdown. However, the potential influence of protein supplementation on post-exercise SC regulation in human skeletal muscle has not been well investigated. In a comparative human study, we investigated the effect of hydrolyzed whey protein supplementation following eccentric exercise on fiber type-specific SC accumulation. Twenty-four young healthy subjects received either hydrolyzed whey protein + carbohydrate (whey, n = 12) or iso-caloric carbohydrate (placebo, n = 12) during post-exercise recovery from 150 maximal unilateral eccentric contractions. Prior to and 24, 48 and 168 h post-exercise, muscle biopsies were obtained from the exercise leg and analyzed for fiber type-specific SC content. Maximal voluntary contraction (MVC) and serum creatine kinase (CK) were evaluated as indices of recovery from muscle damage. In type II fiber-associated SCs, the whey group increased SCs/fiber from 0.05 [0.02; 0.07] to 0.09 [0.06; 0.12] (p < 0.05) and 0.11 [0.06; 0.16] (p < 0.001) at 24 and 48 h, respectively, and exhibited a difference from the placebo group (p < 0.05) at 48 h. The whey group increased SCs/myonuclei from 4 % [2; 5] to 10 % [4; 16] (p < 0.05) at 48 h, whereas the placebo group increased from 5 % [2; 7] to 9 % [3; 16] (p < 0.01) at 168 h. MVC decreased (p < 0.001) and muscle soreness and CK increased (p < 0.001), irrespective of supplementation. In conclusion, whey protein supplementation may accelerate SC proliferation as part of the regeneration or remodeling process after high-intensity eccentric exercise.

Task-specificity of bilateral anticipatory activation of the deep abdominal muscles in healthy and chronic low back pain populations.

PubMed

Massé-Alarie, Hugo; Beaulieu, Louis-David; Preuss, Richard; Schneider, Cyril

2015-02-01

Cross-sectional study of lumbopelvic muscle activation during rapid limb movements in chronic low back pain (CLBP) patients and healthy controls. Controversy exists over whether bilateral anticipatory activation of the deep abdominal muscles represents a normal motor control strategy prior to all rapid limb movements, or if this is simply a task-specific strategy appropriate for only certain movement conditions. To assess the onset timing of the transversus abdominis/internal oblique muscles (TrA/IO) during two rapid limb movement tasks with different postural demands - bilateral shoulder flexion in standing, unilateral hip extension in prone lying - as well as differences between CLBP and controls. Twelve CLBP and 13 controls performed the two tasks in response to an auditory cue. Surface EMG was acquired bilaterally from five muscles, including TrA/IO. In both groups, 50% of bilateral shoulder flexion trials showed bilateral anticipatory TrA/IO activation. This was rare, however, in unilateral hip extension for which only the TrA/IO contralateral to the moving leg showed anticipatory activation. The only significant difference in lumbo-pelvic muscle onset timing between CLBP and controls was a delay in semitendinosus activation during bilateral shoulder flexion in standing. Our data suggest that bilateral anticipatory TrA/IO activation is a task-specific motor control strategy, appropriate for only certain rapid limb movement conditions. Furthermore, the presence of altered semitendinosus onset timing in the CLBP group during bilateral shoulder flexion may be reflective of other possible lumbo-pelvic motor control alterations among this population. Copyright © 2014 Elsevier B.V. All rights reserved.

Analysis of fiber type transformation and histology in chronic electrically stimulated canine rectus abdominis muscle island-flap stomal sphincters.

PubMed

Majzoub, Ramsey K; Bardoel, Janou W J M; Maldonado, Claudio; Barker, John H; Stadelmann, Wayne K

2003-01-01

Dynamic skeletal muscle flaps are designed to perform a specific functional task through contraction and relaxation of their muscle fibers. The most commonly used dynamic skeletal flaps today are for cardiomyoplasty and anal or urinary myoplasty. Low-frequency chronic stimulation of these flaps enables them to use their intrinsic energy stores in a more efficient manner through aerobic metabolic pathways for increased endurance and improved work capacity. The purpose of this study was to (1) determine whether fiber type transformation from fatigue-prone (type II) muscle fibers to fatigue-resistant (type I) muscle fibers could be demonstrated in the authors' chronic canine stomal sphincter model where the rectus abdominis muscle was used to create a functional stomal sphincter, (2) assess whether there is any correlation between the degree of muscle fiber type transformation and the continence times, and (3) examine the long-term effects of the training regimens on the skeletal muscle fibers through histologic and volumetric analysis. Eight dynamic island-flap sphincters were created from a part of the rectus abdominis muscle in mongrel dogs by preserving the deep inferior epigastric vascular pedicle and the most caudal investing intercostal nerve. The muscular sphincters were wrapped around a blind loop of distal ileum and trained with pacing electrodes. Two different training protocols were used. In group A (n = 4), a preexisting anal dynamic graciloplasty training protocol was used. A revised protocol was used in group B (n = 4). Muscle biopsy specimens were obtained before and after training from the rectus abdominis muscle sphincter. Fiber type transformation was assessed using a monoclonal antibody directed against the fatigue-prone type II fibers. Pretraining and posttraining skeletal muscle specimens were examined histologically. A significant fiber type conversion was achieved in both group A and group B animals, with each group achieving greater than 50 percent conversion from fatigue-prone (type II) muscle fibers to fatigue-resistant (type I) muscle fibers. The continence time was different for both groups. Biopsy specimens 1 cm from the electrodes revealed that fiber type transformation was uniform throughout this region of the sphincters. Skeletal muscle fibers within both groups demonstrated a reduction in their fiber diameter and volume. Fiber type transformation is possible in this unique canine island-flap rectus abdominis sphincter model. The relative design of the flap with preservation of the skeletal muscle resting length and neuronal and vascular supply are important characteristics when designing a functional dynamic flap for stomal continence.

Overexpression of IGF-I in skeletal muscle of transgenic mice does not prevent unloading-induced atrophy

NASA Technical Reports Server (NTRS)

Criswell, D. S.; Booth, F. W.; DeMayo, F.; Schwartz, R. J.; Gordon, S. E.; Fiorotto, M. L.

1998-01-01

This study examined the association between local insulin-like growth factor I (IGF-I) overexpression and atrophy in skeletal muscle. We hypothesized that endogenous skeletal muscle IGF-I mRNA expression would decrease with hindlimb unloading (HU) in mice, and that transgenic mice overexpressing human IGF-I (hIGF-I) specifically in skeletal muscle would exhibit less atrophy after HU. Male transgenic mice and nontransgenic mice from the parent strain (FVB) were divided into four groups (n = 10/group): 1) transgenic, weight-bearing (IGF-I/WB); 2) transgenic, hindlimb unloaded (IGF-I/HU); 3) nontransgenic, weight-bearing (FVB/WB); and 4) nontransgenic, hindlimb unloaded (FVB/HU). HU groups were hindlimb unloaded for 14 days. Body mass was reduced (P < 0.05) after HU in both IGF-I (-9%) and FVB mice (-13%). Contrary to our hypothesis, we found that the relative abundance of mRNA for the endogenous rodent IGF-I (rIGF-I) was unaltered by HU in the gastrocnemius (GAST) muscle of wild-type FVB mice. High-level expression of hIGF-I peptide and mRNA was confirmed in the GAST and tibialis anterior (TA) muscles of the transgenic mice. Nevertheless, masses of the GAST and TA muscles were reduced (P < 0.05) in both FVB/HU and IGF-I/HU groups compared with FVB/WB and IGF-I/WB groups, respectively, and the percent atrophy in mass of these muscles did not differ between FVB and IGF-I mice. Therefore, skeletal muscle atrophy may not be associated with a reduction of endogenous rIGF-I mRNA level in 14-day HU mice. We conclude that high local expression of hIGF-I mRNA and peptide in skeletal muscle alone cannot attenuate unloading-induced atrophy of fast-twitch muscle in mice.

Impact of protein supplementation and exercise in preventing changes in gene expression profiling in woman muscles after long-term bedrest as revealed by microarray analysis.

NASA Astrophysics Data System (ADS)

Chopard, Angele; Lecunff, Martine; Danger, Richard; Teusan, Raluca; Jasmin, Bernard J.; Marini, Jean-Francois; Leger, Jean

Long duration space flights have a dramatic impact on human physiology and under such a condition, skeletal muscles are known to be one of the most affected systems. A thorough understanding of the basic mechanisms leading to muscle impairment under microgravity, which causes significant loss of muscle mass as well as structural disorders, is necessary for the development of efficient space flight countermeasures. This study was conducted under the aegis of the European Space Agency (ESA), the National Aeronautics and Space Administration of the USA (NASA), the Canadian Space Agency (CSA), and the French "Centre National d'Etudes Spatiales" (CNES). It gave us the opportunity to investigate for the first time the effects of prolonged disuse (long-term bedrest, LTBR) on the transcriptome of different muscle types in healthy women (control, n=8), as well as the potential beneficial impact of protein supplementation (nutrition, n=8) and a combined resistance and aerobic exercise training program (exercise, n=8). Pre- (LTBR -8) and post- (LTBR +59) biopsies were obtained from vastus lateralis (VL) and soleus (SOL) muscles from each subject. Skeletal muscle gene expression profiles were obtained using a custom made microarray containing 6681 muscle-relevant genes. 555 differentiallyexpressed and statistically-significant genes were identified in control group following 60 days of LTBR, including 348 specific for SOL, 83 specific for VL, and 124 common for the two types of muscle (p<0.05). After LTBR, both muscle types exhibited a consistent decrease in pathways involved in fatty acid oxidation, ATP synthesis, and oxidative phosphorylation (p<0.05). However, the postural SOL muscle exhibited a higher level of changes with mRNA encoding proteins involved in protein synthesis and activation of protein degradation (mainly ubiquitinproteasome components) (p<0.05). Major changes in muscle function, such as those involved in calcium signaling and muscle structure including modifications of extracellular matrix and cytoskeletal components, were significant in SOL. Among the two recently described markers of atrophy, only MAFbx transcripts exhibited an increase in VL following 60 days of LTBR. While protein supplementation reduced the number of differentially-expressed genes by 40 and 25% for SOL and VL, respectively, the combined exercise regimen resulted in a marked beneficial and compensatory effect by decreasing the number of differentially-expressed mRNAs by more than 90% in both SOL and VL muscles. Together, these findings provide an overview of skeletal muscle impairment following prolonged disuse by identifying specific groups of genes related to muscle function, as well as metabolic and canonical signaling pathways. Furthermore, these results highlight the importance of regular exercise in the maintenance of both slow and fast muscle phenotypes. Finally, our approach will prove useful in designing and optimizing specific countermeasures aimed at counteracting muscle atrophy in a microgravity environment.

Coenzyme Q10 Supplementation Decreases Statin-Related Mild-to-Moderate Muscle Symptoms: A Randomized Clinical Study

PubMed Central

Skarlovnik, Ajda; Janić, Miodrag; Lunder, Mojca; Turk, Martina; Šabovič, Mišo

2014-01-01

Background Statin use is frequently associated with muscle-related symptoms. Coenzyme Q10 supplementation has yielded conflicting results in decreasing statin myopathy. Herein, we tested whether coenzyme Q10 supplementation could decrease statin-associated muscular pain in a specific group of patients with mild-to-moderate muscle symptoms. Material/Methods Fifty patients treated with statins and reporting muscle pain were recruited. The Q10 group (n=25) received coenzyme Q10 supplementation over a period of 30 days (50 mg twice daily), and the control group (n=25) received placebo. The Brief Pain Inventory (BPI) questionnaire was used and blood testing was performed at inclusion in the study and after 30 days of supplementation. Results The intensity of muscle pain, measured as the Pain Severity Score (PSS), in the Q10 group was reduced from 3.9±0.4 to 2.9±0.4 (P<0.001). The Pain Interference Score (PIS) after Q10 supplementation was reduced from 4.0±0.4 to 2.6±0.4 (P<0.001). In the placebo group, PSS and PIS did not change. Coenzyme Q10 supplementation decreased statin-related muscle symptoms in 75% of patients. The relative values of PSS and PIS significantly decreased (−33.1% and −40.3%, respectively) in the Q10 group compared to placebo group (both P<0.05). From baseline, no differences in liver and muscle enzymes or cholesterol values were found. Conclusions The present results show that coenzyme Q10 supplementation (50 mg twice daily) effectively reduced statin-related mild-to-moderate muscular symptoms, causing lower interference of statin-related muscular symptoms with daily activities. PMID:25375075

Coenzyme Q10 supplementation decreases statin-related mild-to-moderate muscle symptoms: a randomized clinical study.

PubMed

Skarlovnik, Ajda; Janić, Miodrag; Lunder, Mojca; Turk, Martina; Šabovič, Mišo

2014-11-06

Statin use is frequently associated with muscle-related symptoms. Coenzyme Q10 supplementation has yielded conflicting results in decreasing statin myopathy. Herein, we tested whether coenzyme Q10 supplementation could decrease statin-associated muscular pain in a specific group of patients with mild-to-moderate muscle symptoms. Fifty patients treated with statins and reporting muscle pain were recruited. The Q10 group (n=25) received coenzyme Q10 supplementation over a period of 30 days (50 mg twice daily), and the control group (n=25) received placebo. The Brief Pain Inventory (BPI) questionnaire was used and blood testing was performed at inclusion in the study and after 30 days of supplementation. The intensity of muscle pain, measured as the Pain Severity Score (PSS), in the Q10 group was reduced from 3.9±0.4 to 2.9±0.4 (P<0.001). The Pain Interference Score (PIS) after Q10 supplementation was reduced from 4.0±0.4 to 2.6±0.4 (P<0.001). In the placebo group, PSS and PIS did not change. Coenzyme Q10 supplementation decreased statin-related muscle symptoms in 75% of patients. The relative values of PSS and PIS significantly decreased (-33.1% and -40.3%, respectively) in the Q10 group compared to placebo group (both P<0.05). From baseline, no differences in liver and muscle enzymes or cholesterol values were found. The present results show that coenzyme Q10 supplementation (50 mg twice daily) effectively reduced statin-related mild-to-moderate muscular symptoms, causing lower interference of statin-related muscular symptoms with daily activities.

Skeletal Muscle Triglycerides, Diacylglycerols, and Ceramides in Insulin Resistance

PubMed Central

Amati, Francesca; Dubé, John J.; Alvarez-Carnero, Elvis; Edreira, Martin M.; Chomentowski, Peter; Coen, Paul M.; Switzer, Galen E.; Bickel, Perry E.; Stefanovic-Racic, Maja; Toledo, Frederico G.S.; Goodpaster, Bret H.

2011-01-01

OBJECTIVE Chronic exercise and obesity both increase intramyocellular triglycerides (IMTGs) despite having opposing effects on insulin sensitivity. We hypothesized that chronically exercise-trained muscle would be characterized by lower skeletal muscle diacylglycerols (DAGs) and ceramides despite higher IMTGs and would account for its higher insulin sensitivity. We also hypothesized that the expression of key skeletal muscle proteins involved in lipid droplet hydrolysis, DAG formation, and fatty-acid partitioning and oxidation would be associated with the lipotoxic phenotype. RESEARCH DESIGN AND METHODS A total of 14 normal-weight, endurance-trained athletes (NWA group) and 7 normal-weight sedentary (NWS group) and 21 obese sedentary (OBS group) volunteers were studied. Insulin sensitivity was assessed by glucose clamps. IMTGs, DAGs, ceramides, and protein expression were measured in muscle biopsies. RESULTS DAG content in the NWA group was approximately twofold higher than in the OBS group and ~50% higher than in the NWS group, corresponding to higher insulin sensitivity. While certain DAG moieties clearly were associated with better insulin sensitivity, other species were not. Ceramide content was higher in insulin-resistant obese muscle. The expression of OXPAT/perilipin-5, adipose triglyceride lipase, and stearoyl-CoA desaturase protein was higher in the NWA group, corresponding to a higher mitochondrial content, proportion of type 1 myocytes, IMTGs, DAGs, and insulin sensitivity. CONCLUSIONS Total myocellular DAGs were markedly higher in highly trained athletes, corresponding with higher insulin sensitivity, and suggest a more complex role for DAGs in insulin action. Our data also provide additional evidence in humans linking ceramides to insulin resistance. Finally, this study provides novel evidence supporting a role for specific skeletal muscle proteins involved in intramyocellular lipids, mitochondrial oxidative capacity, and insulin resistance. PMID:21873552

Accuracy of the surface electromyography RMS processing for the diagnosis of myogenous temporomandibular disorder.

PubMed

Berni, Kelly Cristina dos Santos; Dibai-Filho, Almir Vieira; Pires, Paulo Fernandes; Rodrigues-Bigaton, Delaine

2015-08-01

Due to the multifactor etiology of temporomandibular disorder (TMD), the precise diagnosis remains a matter of debate and validated diagnostic tools are needed. The aim was to determine the accuracy of surface electromyography (sEMG) activity, assessed in the amplitude domain by the root mean square (RMS), in the diagnosis of TMD. One hundred twenty-three volunteers were evaluated using the Research Diagnostic Criteria for Temporomandibular Disorders and distributed into two groups: women with myogenous TMD (n=80) and women without TMD (n=43). The volunteers were then submitted to sEMG evaluation of the anterior temporalis, masseter and suprahyoid muscles at rest and during maximum voluntary teeth clenching (MVC) on parafilm. The accuracy, sensitivity and specificity of the muscle activity were analyzed. Differences between groups were found in all muscles analyzed at rest as well as in the masseter and suprahyoid muscles during MVC on parafilm. Moderate accuracy (AUC: 0.74-0.84) of the RMS sEMG was found in all muscles regarding the diagnosis of TMD at rest and in the suprahyoid muscles during MVC on parafilm. Moreover, sensitivity ranging from 71.3% to 80% and specificity from 60.5% to 76.6%. In contrast, RMS sEMG did not exhibit acceptable degrees of accuracy in the other masticatory muscles during MVC on parafilm. It was concluded that the RMS sEMG is a complementary tool for clinical diagnosis of the myogenous TMD. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electromyographic Assessment of Functional Symmetry of Paraspinal Muscles during Static Exercises in Adolescents with Idiopathic Scoliosis

PubMed Central

Chwała, Wiesław; Koziana, Agnieszka; Kasperczyk, Tadeusz; Płaszewski, Maciej

2014-01-01

Background. The question of how to correct and rehabilitate scoliosis remains one of the most difficult problems of orthopaedics. Controversies continue to arise regarding various types of both symmetric and asymmetric scoliosis-specific therapeutic exercises. Objective. The aim of the present paper was to conduct an electromyographic assessment of functional symmetry of paraspinal muscles during symmetric and asymmetric exercises in adolescents with idiopathic scoliosis. Materials and Methods. The study was conducted in a group of 82 girls, mean age 12.4 ± 2.3 years with single- or double-major-idiopathic scoliosis, Cobb angle 24 ± 9.4°. The functional biopotentials during isometric work of paraspinal muscles in “at rest” position and during two symmetric and four asymmetric exercises were measured with the use of the Muscle Tester ME 6000 electromyograph. Results. In general, asymmetric exercises were characterised by larger differences in bioelectrical activity of paraspinal muscles, in comparison with symmetric exercises, both in the groups of patients with single-curve and double-curve scoliosis. Conclusion. During symmetric and asymmetric exercises, muscle tension patterns differed significantly in both groups, in comparison with the examination at rest, in most cases generating positive corrective patterns. Asymmetric exercises generated divergent muscle tension patterns on the convex and concave sides of the deformity. PMID:25258713

Combined effects of functionally-oriented exercise regimens and nutritional supplementation on both the institutionalised and free-living frail elderly (double-blind, randomised clinical trial).

PubMed

Zak, Marek; Swine, Christian; Grodzicki, Tomasz

2009-01-28

Consistently swelling proportion of the frail elderly within a modern society challenges the overstrained public health sector to provide both adequate medical care and comprehensive assistance in their multiple functional deficits of daily living. Easy-to-apply and task-specific ways of addressing this issue are being sought out, with a view to proposing systemic solutions for nationwide application. The present randomised, double-blind, placebo-controlled, 7-week clinical trial aimed to determine whether specifically structured, intensive exercise regimens, combined with nutritional supplementation, might improve and help sustain individual muscle strength and mobility, and possibly enhance individual functional capabilities in an on-going quest for active prevention of care-dependency. Ninety-one frail elderly (F 71 M 20; mean age 79 years) were recruited from both nursing home residents and community dwellers and randomly split into four groups: Group I - progressive resistance exercises (PRE) + functionally-oriented exercises (FOE) + nutritional supplementation (NS), Group II - PRE + FOE + placebo, Group III--standard exercises (SE) + FOE + NS, Group IV - SE + FOE + placebo. Each group pursued a 45 min. exercise session 5 times weekly. The subjects' strength with regard to four muscle groups, i.e. hip and knee extensors and flexons, was assessed at 80% (1 RM) weekly, whereas their balance and mobility at baseline and at the end of the study. The study was completed by 80 subjects. Despite its relatively short duration significant differences in muscle strength were noted both in Group I and Group II (p = 0.01; p = 0.04; respectively), although this did not translate directly into perceptible improvement in individual mobility. Notable improvements in individual mobility were reported in Group III and Group IV (p = 0.002), although without positive impact on individual muscle strength. Comprehensively structured, high-intensity regimen made up of diverse exercise types, i.e. functionally-oriented, progressive resistance and standard ones, preferably if combined with nutritional supplementation in adequate volume, demonstrates clear potential for appreciably improving overall functional status in the frail elderly in terms of individual walking capacity and muscle strength. Central Register of Clinical Trials, Poland--CEBK180/2000.

Alterations of the In Vivo Torque-Velocity Relationship of Human Skeletal Muscle Following 30 Days Exposure to Simulated Microgravity

NASA Technical Reports Server (NTRS)

Dudley, Gary A.; Duvoisin, Marc R.; Convertino, Victor A.; Buchanan, Paul

1989-01-01

The purpose of this study was to examine the effect of 30 d of 6 deg headdown bedrest (BR) on the in vivo strength of skeletal muscle. Peak angle specific (0.78 rad below horizontal) torque of the knee extensor (KE) and flexor (KF) muscle groups of both limbs was assessed during unilateral efforts at four speeds (0.52, 1.74, 2.97 and 4.19 rad/s) during concentric and at three speeds (0.52, 1.74 and 2.97 rad/s) during eccentric actions. The average decrease (P less than 0.05) of peak angle specific torque directly post-BR for the KE across speeds of concentric and eccentric actions was about 19% (n = 7). Recovery for 30 d following BR markedly improved strength to about 92% (P greater than 0.05) of 'normal'. Strength of the KF was not altered (P greater than 0.05) by BR (about a 6% decrease independent of speed and type of muscle action). Changes of strength were not affected by the type or speed of muscle action. The results indicate that strength of ex-tensor more than of flexor muscle groups of the lower limb is decreased by 30 d of bedrest and that this response does not alter the nature of the in vivo torque-velocity relation.

Facial responsiveness of psychopaths to the emotional expressions of others

PubMed Central

Mokros, Andreas; Olderbak, Sally; Wilhelm, Oliver

2018-01-01

Psychopathic individuals show selfish, manipulative, and antisocial behavior in addition to emotional detachment and reduced empathy. Their empathic deficits are thought to be associated with a reduced responsiveness to emotional stimuli. Immediate facial muscle responses to the emotional expressions of others reflect the expressive part of emotional responsiveness and are positively related to trait empathy. Empirical evidence for reduced facial muscle responses in adult psychopathic individuals to the emotional expressions of others is rare. In the present study, 261 male criminal offenders and non-offenders categorized dynamically presented facial emotion expressions (angry, happy, sad, and neutral) during facial electromyography recording of their corrugator muscle activity. We replicated a measurement model of facial muscle activity, which controls for general facial responsiveness to face stimuli, and modeled three correlated emotion-specific factors (i.e., anger, happiness, and sadness) representing emotion specific activity. In a multi-group confirmatory factor analysis, we compared the means of the anger, happiness, and sadness latent factors between three groups: 1) non-offenders, 2) low, and 3) high psychopathic offenders. There were no significant mean differences between groups. Our results challenge current theories that focus on deficits in emotional responsiveness as leading to the development of psychopathy and encourage further theoretical development on deviant emotional processes in psychopathic individuals. PMID:29324826

Exercise-induced muscle glucose uptake in mice with graded, muscle-specific GLUT-4 deletion.

PubMed

Howlett, Kirsten F; Andrikopoulos, Sofianos; Proietto, Joseph; Hargreaves, Mark

2013-08-01

To investigate the importance of the glucose transporter GLUT-4 for muscle glucose uptake during exercise, transgenic mice with skeletal muscle GLUT-4 expression approximately 30-60% of normal (CON) and approximately 5-10% of normal (KO) were generated using the Cre/Lox system and compared with wild-type (WT) mice during approximately 40 min of treadmill running (KO: 37.7 ± 1.3 min; WT: 40 min; CON: 40 min, P = 0.18). In WT and CON animals, exercise resulted in an overall increase in muscle glucose uptake. More specifically, glucose uptake was increased in red gastrocnemius of WT mice and in the soleus and red gastrocnemius of CON mice. In contrast, the exercise-induced increase in muscle glucose uptake in all muscles was completely abolished in KO mice. Muscle glucose uptake increased during exercise in both red and white quadriceps of WT mice, while the small increases in CON mice were not statistically significant. In KO mice, there was no change at all in quadriceps muscle glucose uptake. No differences in muscle glycogen use during exercise were observed between any of the groups. However, there was a significant increase in plasma glucose levels after exercise in KO mice. The results of this study demonstrated that a reduction in skeletal muscle GLUT-4 expression to approximately 10% of normal levels completely abolished the exercise-induced increase in muscle glucose uptake.

Fasciculations in nerve and muscle disorders - A prospective study of muscle ultrasound compared to electromyography.

PubMed

Johansson, M T; Ellegaard, H R; Tankisi, H; Fuglsang-Frederiksen, A; Qerama, E

2017-11-01

We examined the clinical utility of muscle ultrasound (MUS) in detecting fasciculations in patients with nerve and muscle disorders (NMD) and investigated the impact on diagnostic sensitivity when combining electromyography (EMG) and MUS. We included 58 consecutive patients suspected to have NMD and 38 healthy subjects (HS). Patients and HS underwent MUS in 14 skeletal and two bulbar muscles and the video recordings of the MUS were anonymised. Only patients underwent EMG. The follow-up diagnoses were: 15 Amyotrophic lateral sclerosis (ALS), 15 polyneuropathy, 14 patients had other diagnoses (disease-control group) and 14 patients had no pathological findings. MUS detected more muscles with fasciculations among ALS patients compared to all other groups. In ALS patients, the dominating pattern of fasciculations was continuous (45%). More proximal muscles showed fasciculations among ALS patients compared to all other patient groups. MUS was more sensitive than EMG in detecting fasciculations (58% vs. 48%). When combining the two methods, the sensitivity in detecting fasciculations increased to 65%. Fasciculations in nine muscles could predict the ALS diagnosis with high sensitivity and specificity. MUS is a sensitive tool in detecting fasciculations in patients with NMD and performs well compared to EMG in diagnosing ALS. MUS may add valuable information in the clinic, especially in diagnosing ALS. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Morphogenesis and Cell Fate Determination within the Adaxial Cell Equivalence Group of the Zebrafish Myotome

PubMed Central

Nguyen-Chi, Mai E.; Bryson-Richardson, Robert; Sonntag, Carmen; Hall, Thomas E.; Gibson, Abigail; Sztal, Tamar; Chua, Wendy; Schilling, Thomas F.; Currie, Peter D.

2012-01-01

One of the central questions of developmental biology is how cells of equivalent potential—an equivalence group—come to adopt specific cellular fates. In this study we have used a combination of live imaging, single cell lineage analyses, and perturbation of specific signaling pathways to dissect the specification of the adaxial cells of the zebrafish embryo. We show that the adaxial cells are myogenic precursors that form a cell fate equivalence group of approximately 20 cells that consequently give rise to two distinct sub-types of muscle fibers: the superficial slow muscle fibers (SSFs) and muscle pioneer cells (MPs), distinguished by specific gene expression and cell behaviors. Using a combination of live imaging, retrospective and indicative fate mapping, and genetic studies, we show that MP and SSF precursors segregate at the beginning of segmentation and that they arise from distinct regions along the anterior-posterior (AP) and dorsal-ventral (DV) axes of the adaxial cell compartment. FGF signaling restricts MP cell fate in the anterior-most adaxial cells in each somite, while BMP signaling restricts this fate to the middle of the DV axis. Thus our results reveal that the synergistic actions of HH, FGF, and BMP signaling independently create a three-dimensional (3D) signaling milieu that coordinates cell fate within the adaxial cell equivalence group. PMID:23133395

Glenohumeral joint translation and muscle activity in patients with symptomatic rotator cuff pathology: An ultrasonographic and electromyographic study with age-matched controls.

PubMed

Rathi, Sangeeta; Taylor, Nicholas F; Soo, Brendan; Green, Rodney A

2018-03-02

To determine whether patients with symptomatic rotator cuff pathology had more glenohumeral joint translation and different patterns of rotator cuff muscle activity compared to controls. Repeated measurements of glenohumeral translation and muscle activity in two positions and six testing conditions in two groups. Twenty participants with a symptomatic and diagnosed rotator cuff tear and 20 age, and gender matched controls were included. Neuromuscular activity was tested by inserting intramuscular electrodes in the rotator cuff muscles. Anterior and posterior glenohumeral translations were measured using real time ultrasound in testing conditions (with and without translation force, with and without isometric internal and external rotation), in two positions (shoulder neutral, 90° of abduction) and two force directions (anterior, posterior). Symptomatic pathology group demonstrated increased passive glenohumeral translation with posterior translation force (p<0.05). Overall, rotator cuff muscle contraction in the pathology group limited joint translation in a similar manner to the control group, but they did not show the normal direction specific pattern in the neutral posterior position (p<0.03). The pathology group demonstrated reduced EMG activity in the upper infraspinatus muscle relative to the reference position (p<0.02) with anterior translation force and in the supraspinatus (p<0.05) muscle with anterior and posterior translation force in the abducted position. Symptomatic pathology resulted in increased passive glenohumeral joint translation. Although there were some reductions in muscle activity with injury, their rotator cuff still controlled glenohumeral translation. These results highlight the need to consider joint translation in the assessment and management of patients with rotator cuff injury. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

[Clinical profile of persistent generalized muscle contraction following the insult of developing brain].

PubMed

Maruyama, Koichi; Iai, Mizue; Arai, Hiroshi; Yokochi, Kenji

2014-01-01

Persons with severe motor and intellectual disabilities (SMID) caused by injury to the developing brain sometimes present generalized hypertonia in a specific position with extreme muscle overactivity persisting for most of the time during wakefulness. This "persistent generalized muscle contraction" is often associated with bad humor, sleep disturbance, hyperhidrosis, wasting, elevation of serum creatine kinase levels, regular daytime use of hypnotic or sedative medication, and the necessity to maintain the neck or hip in a flexed position manually. The aim of this study is to elucidate the clinical profile of this condition. We retrospectively examined the medical records and brain imaging data of 66 SMID patients in the state of persistent generalized muscle contraction. Most patients could be classified into 2 major categories on the basis of clinical presentation and brain imaging: (A) those with premature birth and bilateral lesion of globus pallidus interna (kernicterus) (n = 16), and (B) those with various widespread bilateral basal ganglia/thalamic and/or cerebral lesions such as hypoxia-ischemia, acute encephalopathy, malformation, etc (n = 50). Group A assumed an asymmetrical tonic-neck-reflex-like position, torsion of the trunk, fluctuation of hypertonia, and better mental development. Three of them exhibited extreme hypertonia resembling status dystonicus. Group B often exhibited persistent and fixed retroflexion of the neck and trunk or opisthotonus. Drugs such as oral muscular relaxants were ineffective in both groups. Injection of botulinum toxin into the cervical and paravertebral muscles partially alleviated symptoms. Persistent generalized muscle contraction in SMID has at least two different types. Group A has characteristics of severe dystonic hypertonia that could lead to status dystonicus. Group B might have peculiar characteristics of muscle overactivity triggered by wakefulness or discomfort, which probably results from inability to achieve spontaneous muscle relaxation.

Force per cross-sectional area from molecules to muscles: a general property of biological motors

PubMed Central

Meyer-Vernet, Nicole

2016-01-01

We propose to formally extend the notion of specific tension, i.e. force per cross-sectional area—classically used for muscles, to quantify forces in molecular motors exerting various biological functions. In doing so, we review and compare the maximum tensions exerted by about 265 biological motors operated by about 150 species of different taxonomic groups. The motors considered range from single molecules and motile appendages of microorganisms to whole muscles of large animals. We show that specific tensions exerted by molecular and non-molecular motors follow similar statistical distributions, with in particular, similar medians and (logarithmic) means. Over the 1019 mass (M) range of the cell or body from which the motors are extracted, their specific tensions vary as Mα with α not significantly different from zero. The typical specific tension found in most motors is about 200 kPa, which generalizes to individual molecular motors and microorganisms a classical property of macroscopic muscles. We propose a basic order-of-magnitude interpretation of this result. PMID:27493785

Nonshivering thermogenesis in king penguin chicks. II. Effect of fasting.

PubMed

Duchamp, C; Barré, H; Rouanet, J L; Lanni, A; Cohen-Adad, F; Berne, G; Brebion, P

1991-12-01

The effect of fasting on the energy metabolism of skeletal muscle and liver was investigated in cold-acclimatized short-term fasting (STF) (3 wk) and naturally long-term fasting (LTF) (4-5 mo) king penguin chicks, both groups exhibiting nonshivering thermogenesis (NST). A comparison was made with nourished cold-acclimatized controls. In these chicks, no brown adipose tissue deposits could be found on electron-microscopic observations of fat deposits. Protein content and cytochrome oxidase (CO) activity of tissue homogenates were measured in liver and pectoralis and gastrocnemius muscles, as were protein content, CO activity, and respiration rates of mitochondria isolated from these organs. Fasting-induced protein loss affected the pectoralis more than the gastrocnemius muscle, thus preserving locomotor function. In STF chicks, specific mitochondrial protein content and specific tissue CO activity were preserved but total organ CO capacity was reduced by half in pectoralis and liver following the fall in organ mass. In LTF chicks, both specific and total CO activity were drastically reduced in muscles, whereas specific CO activity was preserved in liver. In these LTF chicks, muscle mitochondria showed an energized configuration associated with an increased area of inner membrane in gastrocnemius. A reduction of respiratory control ratio (RCR) was observed in subsarcolemmal muscle mitochondria of STF chicks, whereas intermyofibrillar and liver mitochondria kept high RCR values.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle free amino acid profiles are related to differences in skeletal muscle growth between single and twin ovine fetuses near term.

PubMed

Sales, Francisco; Pacheco, David; Blair, Hugh; Kenyon, Paul; McCoard, Sue

2013-01-01

Twin sheep fetuses have reduced skeletal muscle weight near birth relative to singles as a result of restricted muscle hypertrophy. Intracellular free amino acids (FAA) are reported to regulate metabolic pathways which control muscle protein accretion, whereby reduced intracellular content of specific FAA may reduce their activation and therefore, muscle hypertrophy. The aim of this study was to determine whether differences in muscle weight between singleton and twin fetuses, under different maternal conditions is associated with reduced concentration of specific FAA. The FAA content in the semitendinosus muscle (ST) in singleton and twin fetuses (rank) at 140 days of gestation from heavy (H) or light (L) ewes fed ad libitum (A) or maintenance (M) level of nutrition was measured. Muscle weight was reduced in twin fetuses compared to singletons in all groups. Reduced concentrations of leucine, threonine and valine, but higher concentrations of methionine, ornithine, lysine and serine were found in twin fetuses compared to singletons. Maternal size and nutrition interaction with rank resulted in reduced glutamine in twins from HM-ewes (H-ewes under M nutrition) compared to their singleton counterparts. Maternal weight interaction with pregnancy rank reduced the concentration of arginine in twins, with a larger effect on H-ewes compared with L-ewes. Maternal size interaction with pregnancy rank resulted in twins from M-ewes to have lower alanine, while twins from A-ewes had lower aspartic acid concentration compared to singletons. The ST muscle weight was positively correlated only with arginine concentration after taking into account rank, size and nutrition. The present results indicate that reduced concentrations of specific intracellular FAA, such as arginine, leucine, valine, glutamine, which are known to play a role in muscle growth, could be acting as limiting factors for muscle hypertrophy in twin fetuses during late gestation. Ewe size and nutrition can influence the concentration of specific FAA in muscle and should be considered in any intervention plan to improve twin fetal muscle growth.

A three-dimensional muscle activity imaging technique for assessing pelvic muscle function

NASA Astrophysics Data System (ADS)

Zhang, Yingchun; Wang, Dan; Timm, Gerald W.

2010-11-01

A novel multi-channel surface electromyography (EMG)-based three-dimensional muscle activity imaging (MAI) technique has been developed by combining the bioelectrical source reconstruction approach and subject-specific finite element modeling approach. Internal muscle activities are modeled by a current density distribution and estimated from the intra-vaginal surface EMG signals with the aid of a weighted minimum norm estimation algorithm. The MAI technique was employed to minimally invasively reconstruct electrical activity in the pelvic floor muscles and urethral sphincter from multi-channel intra-vaginal surface EMG recordings. A series of computer simulations were conducted to evaluate the performance of the present MAI technique. With appropriate numerical modeling and inverse estimation techniques, we have demonstrated the capability of the MAI technique to accurately reconstruct internal muscle activities from surface EMG recordings. This MAI technique combined with traditional EMG signal analysis techniques is being used to study etiologic factors associated with stress urinary incontinence in women by correlating functional status of muscles characterized from the intra-vaginal surface EMG measurements with the specific pelvic muscle groups that generated these signals. The developed MAI technique described herein holds promise for eliminating the need to place needle electrodes into muscles to obtain accurate EMG recordings in some clinical applications.

Effectiveness of platinum-based adjuvant chemotherapy for muscle-invasive bladder cancer: A weighted propensity score analysis.

PubMed

Shimizu, Fumitaka; Muto, Satoru; Taguri, Masataka; Ieda, Takeshi; Tsujimura, Akira; Sakamoto, Yoshiro; Fujita, Kazuhiko; Okegawa, Takatsugu; Yamaguchi, Raizo; Horie, Shigeo

2017-05-01

To evaluate the clinical benefit of adjuvant platinum-based chemotherapy after radical cystectomy for muscle-invasive bladder cancer in routine clinical practice. The present observational study was carried out to compare the effectiveness of adjuvant chemotherapy versus observation post-radical cystectomy in patients with clinically muscle-invasive bladder cancer. Cancer-specific survival and overall survival between the adjuvant chemotherapy group and radical cystectomy alone group were compared using Kaplan-Meier method and log-rank test. After adjusting for background factors using propensity score weighting, differences in cancer-specific survival and overall survival between these two groups were compared. Subgroup analyses by the pathological characteristics were carried out. In total, 322 patients were included in the present study. Of these, 23% received adjuvant chemotherapy post-radical cystectomy. Clinicopathological characteristics showed that patients in the adjuvant chemotherapy group were pathologically more advanced and were at higher risk than the radical cystectomy alone group. In the unadjusted population, although it is not significant, the adjuvant chemotherapy group had lower overall survival (3-year overall survival; 61.5% vs 73.6%, HR 1.33, P = 0.243, log-rank test, adjuvant chemotherapy vs radical cystectomy alone). In the weighted propensity score analysis, although it is not significant, the adjuvant chemotherapy group were superior to radical cystectomy alone groups (overall survival: HR 0.65, 95% CI 0.39-1.09, P = 0.099, log-rank test, adjuvant chemotherapy vs radical cystectomy alone). Subgroup analyses showed that adjuvant chemotherapy significantly reduced the hazard ratio of overall survival and cancer-specific survival in the ≥pT3, pN+, ly+ and v+ subgroups. Platinum-based adjuvant chemotherapy might be associated with increased cancer-specific survival and overall survival in patients with high-risk invasive bladder cancer. © 2017 The Japanese Urological Association.

Force encoding in stick insect legs delineates a reference frame for motor control

PubMed Central

Schmitz, Josef; Chaudhry, Sumaiya; Büschges, Ansgar

2012-01-01

The regulation of forces is integral to motor control. However, it is unclear how information from sense organs that detect forces at individual muscles or joints is incorporated into a frame of reference for motor control. Campaniform sensilla are receptors that monitor forces by cuticular strains. We studied how loads and muscle forces are encoded by trochanteral campaniform sensilla in stick insects. Forces were applied to the middle leg to emulate loading and/or muscle contractions. Selective sensory ablations limited activities recorded in the main leg nerve to specific receptor groups. The trochanteral campaniform sensilla consist of four discrete groups. We found that the dorsal groups (Groups 3 and 4) encoded force increases and decreases in the plane of movement of the coxo-trochanteral joint. Group 3 receptors discharged to increases in dorsal loading and decreases in ventral load. Group 4 showed the reverse directional sensitivities. Vigorous, directional responses also occurred to contractions of the trochanteral depressor muscle and to forces applied at the muscle insertion. All sensory discharges encoded the amplitude and rate of loading or muscle force. Stimulation of the receptors produced reflex effects in the depressor motoneurons that could reverse in sign during active movements. These data, in conjunction with findings of previous studies, support a model in which the trochanteral receptors function as an array that can detect forces in all directions relative to the intrinsic plane of leg movement. The array could provide requisite information about forces and simplify the control and adaptation of posture and walking. PMID:22673329

Effects of warm-up on vertical jump performance and muscle electrical activity using half-squats at low and moderate intensity.

PubMed

Sotiropoulos, Konstantinos; Smilios, Ilias; Christou, Marios; Barzouka, Karolina; Spaias, Angelos; Douda, Helen; Tokmakidis, Savvas P

2010-01-01

The purpose of this study was to determine the effects of a specific warm-up using half-squats at low and moderate intensity on vertical jump performance and electromyographic activity of the thigh muscles. The subjects were 26 men who were divided into a low intensity group (LIG; n = 13) and a moderate intensity group (MIG; n = 13). The LIG performed a specific warm-up protocol that included the explosive execution of half-squats with loads 25 and 35% of the one repetition maximum (1RM) and the MIG with loads 45 and 65% of the 1RM. The two groups performed a countermovement jump (CMJ) before and three minutes after the specific warm-up protocols. During the concentric phase of the CMJ a linear encoder connected to an A/D converter interfaced to a PC with a software for data acquisition and analysis allowed the calculation of average mechanical power. The electromyographic (EMG) activity of the vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) were recorded during the concentric phase of the jumps. The average quadriceps (Qc) activity (mean value of the VL, VM and RF) was also calculated. A two way ANOVA (protocols X time) with repeated measures on the second factor was used to analyze the data. Following the specific warm-up procedure both groups improved (p ≤ 0.05) CMJ performance and mechanical power by 3.5% and 6.3%, respectively, with no differences observed between the two groups. EMG activity of the Qc and VL increased (p ≤ 0.05) for both groups by 5.9% and 8.5%, respectively. It is concluded that the use of a specific warm-up that includes half-squats, performed explosively with low to moderate intensity, improves CMJ performance. This may be due to increased muscle activation as evaluated by the surface EMG. Key pointsThe inclusion of two sets of explosively performed half squats with low to moderate loads in the warm up procedure elicited an acute performance en-hancement.The performance was enhanced regardless of the load used in the warm-up.The performance enhancement is accompanied by a greater electromyographic activity of the knee extensors muscles.

Effects of Warm-Up on Vertical Jump Performance and Muscle Electrical Activity Using Half-Squats at Low and Moderate Intensity

PubMed Central

Sotiropoulos, Konstantinos; Smilios, Ilias; Christou, Marios; Barzouka, Karolina; Spaias, Angelos; Douda, Helen; Tokmakidis, Savvas p.

2010-01-01

The purpose of this study was to determine the effects of a specific warm-up using half-squats at low and moderate intensity on vertical jump performance and electromyographic activity of the thigh muscles. The subjects were 26 men who were divided into a low intensity group (LIG; n = 13) and a moderate intensity group (MIG; n = 13). The LIG performed a specific warm-up protocol that included the explosive execution of half-squats with loads 25 and 35% of the one repetition maximum (1RM) and the MIG with loads 45 and 65% of the 1RM. The two groups performed a countermovement jump (CMJ) before and three minutes after the specific warm-up protocols. During the concentric phase of the CMJ a linear encoder connected to an A/D converter interfaced to a PC with a software for data acquisition and analysis allowed the calculation of average mechanical power. The electromyographic (EMG) activity of the vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) were recorded during the concentric phase of the jumps. The average quadriceps (Qc) activity (mean value of the VL, VM and RF) was also calculated. A two way ANOVA (protocols X time) with repeated measures on the second factor was used to analyze the data. Following the specific warm-up procedure both groups improved (p ≤ 0.05) CMJ performance and mechanical power by 3.5% and 6.3%, respectively, with no differences observed between the two groups. EMG activity of the Qc and VL increased (p ≤ 0.05) for both groups by 5.9% and 8.5%, respectively. It is concluded that the use of a specific warm-up that includes half-squats, performed explosively with low to moderate intensity, improves CMJ performance. This may be due to increased muscle activation as evaluated by the surface EMG. Key points The inclusion of two sets of explosively performed half squats with low to moderate loads in the warm up procedure elicited an acute performance en-hancement. The performance was enhanced regardless of the load used in the warm-up. The performance enhancement is accompanied by a greater electromyographic activity of the knee extensors muscles. PMID:24149703

Exercise-induced muscle glucose uptake in mice with graded, muscle-specific GLUT-4 deletion

PubMed Central

Howlett, Kirsten F; Andrikopoulos, Sofianos; Proietto, Joseph; Hargreaves, Mark

2013-01-01

To investigate the importance of the glucose transporter GLUT-4 for muscle glucose uptake during exercise, transgenic mice with skeletal muscle GLUT-4 expression approximately 30–60% of normal (CON) and approximately 5–10% of normal (KO) were generated using the Cre/Lox system and compared with wild-type (WT) mice during approximately 40 min of treadmill running (KO: 37.7 ± 1.3 min; WT: 40 min; CON: 40 min, P = 0.18). In WT and CON animals, exercise resulted in an overall increase in muscle glucose uptake. More specifically, glucose uptake was increased in red gastrocnemius of WT mice and in the soleus and red gastrocnemius of CON mice. In contrast, the exercise-induced increase in muscle glucose uptake in all muscles was completely abolished in KO mice. Muscle glucose uptake increased during exercise in both red and white quadriceps of WT mice, while the small increases in CON mice were not statistically significant. In KO mice, there was no change at all in quadriceps muscle glucose uptake. No differences in muscle glycogen use during exercise were observed between any of the groups. However, there was a significant increase in plasma glucose levels after exercise in KO mice. The results of this study demonstrated that a reduction in skeletal muscle GLUT-4 expression to approximately 10% of normal levels completely abolished the exercise-induced increase in muscle glucose uptake. PMID:24303141

Differentiating the levels of risk for muscle dysmorphia among Hungarian male weightlifters: a factor mixture modeling approach.

PubMed

Babusa, Bernadett; Czeglédi, Edit; Túry, Ferenc; Mayville, Stephen B; Urbán, Róbert

2015-01-01

Muscle dysmorphia (MD) is a body image disturbance characterized by a pathological preoccupation with muscularity. The study aimed to differentiate the levels of risk for MD among weightlifters and to define a tentative cut-off score for the Muscle Appearance Satisfaction Scale (MASS) for the identification of high risk MD cases. Hungarian male weightlifters (n=304) completed the MASS, the Exercise Addiction Inventory, and specific exercise and body image related questions. For the differentiation of MD, factor mixture modeling was performed, resulting in three independent groups: low-, moderate-, and high risk MD groups. The estimated prevalence of high risk MD in this sample of weightlifters was 15.1%. To determine a cut-off score for the MASS, sensitivity and specificity analyses were performed and a cut-off point of 63 was suggested. The proposed cut-off score for the MASS can be useful for the early detection of high risk MD. Copyright © 2014 Elsevier Ltd. All rights reserved.

Systematic Review of Inspiratory Muscle Training After Cerebrovascular Accident.

PubMed

Martín-Valero, Rocío; De La Casa Almeida, Maria; Casuso-Holgado, Maria Jesus; Heredia-Madrazo, Alfonso

2015-11-01

This systematic review examines levels of evidence and recommendation grades of various therapeutic interventions of inspiratory muscle training in people who have had a stroke. Benefits from different levels of force and resistance in respiratory muscles are shown in this population. This review was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) directives and was completed in November 2014. The search limits were studies published in English between 2004 and 2014. Relevant studies were searched for in MEDLINE, PEDro, OAIster, Scopus, PsycINFO, Web of Knowledge, CINAHL, SPORTDiscus, DOAJ, Cochrane, Embase, Academic Search Complete, Fuente Académica, and MedicLatina. Initially, 20 articles were identified. After analyzing all primary documents, 14 studies were excluded. Only 6 studies were relevant to this review. Three different types of interventions were found (maximum inspiratory training, controlled training, and nonintervention) in 3 different groups. One specific study compared 3 inspiratory muscle training groups with a group of breathing exercises (diaphragmatic exercises with pursed lips) and a control group. Future long-term studies with larger sample sizes are needed. It is necessary to apply respiratory muscle training as a service of the national health system and to consider its inclusion in the conventional neurological program. Copyright © 2015 by Daedalus Enterprises.

Exercises focusing on rotator cuff and scapular muscles do not improve shoulder joint position sense in healthy subjects.

PubMed

Lin, Yin-Liang; Karduna, Andrew

2016-10-01

Proprioception is essential for shoulder neuromuscular control and shoulder stability. Exercise of the rotator cuff and scapulothoracic muscles is an important part of shoulder rehabilitation. The purpose of this study was to investigate the effect of rotator cuff and scapulothoracic muscle exercises on shoulder joint position sense. Thirty-six healthy subjects were recruited and randomly assigned into either a control or training group. The subjects in the training group received closed-chain and open-chain exercises focusing on rotator cuff and scapulothoracic muscles for four weeks. Shoulder joint position sense errors in elevation, including the humerothoracic, glenohumeral and scapulothoracic joints, was measured. After four weeks of exercise training, strength increased overall in the training group, which demonstrated the effect of exercise on the muscular system. However, the changes in shoulder joint position sense errors in any individual joint of the subjects in the training group were not different from those of the control subjects. Therefore, exercises specifically targeting individual muscles with low intensity may not be sufficient to improve shoulder joint position sense in healthy subjects. Future work is needed to further investigate which types of exercise are more effective in improving joint position sense, and the mechanisms associated with those changes. Copyright © 2016 Elsevier B.V. All rights reserved.

Exercises focusing on rotator cuff and scapular muscles do not improve shoulder joint position sense in healthy subjects

PubMed Central

Lin, Yin-Liang; Karduna, Andrew

2016-01-01

Proprioception is essential for shoulder neuromuscular control and shoulder stability. Exercise of the rotator cuff and scapulothoracic muscles is an important part of shoulder rehabilitation. The purpose of this study was to investigate the effect of rotator cuff and scapulothoracic muscle exercises on shoulder joint position sense. Thirty-six healthy subjects were recruited and randomly assigned into either a control or training group. The subjects in the training group received closed-chain and open-chain exercises focusing on rotator cuff and scapulothoracic muscles for four weeks. Shoulder joint position sense errors in elevation, including the humerothoracic, glenohumeral and scapulothoracic joints, was measured. After four weeks of exercise training, strength increased overall in the training group, which demonstrated the effect of exercise on the muscular system. However, the changes in shoulder joint position sense errors in any individual joint of the subjects in the training group were not different from those of the control subjects. Therefore, exercises specifically targeting individual muscles with low intensity may not be sufficient to improve shoulder joint position sense in healthy subjects. Future work is needed to further investigate which types of exercise are more effective in improving joint position sense, and the mechanisms associated with those changes. PMID:27475714

Structural Changes of Lumbar Muscles in Non-specific Low Back Pain: A Systematic Review.

PubMed

Goubert, Dorien; Oosterwijck, Jessica Van; Meeus, Mira; Danneels, Lieven

2016-01-01

Lumbar muscle dysfunction due to pain might be related to altered lumbar muscle structure. Macroscopically, muscle degeneration in low back pain (LBP) is characterized by a decrease in cross-sectional area and an increase in fat infiltration in the lumbar paraspinal muscles. In addition microscopic changes, such as changes in fiber distribution, might occur. Inconsistencies in results from different studies make it difficult to draw firm conclusions on which structural changes are present in the different types of non-specific LBP. Insights regarding structural muscle alterations in LBP are, however, important for prevention and treatment of non-specific LBP. The goal of this article is to review which macro- and/or microscopic structural alterations of the lumbar muscles occur in case of non-specific chronic low back pain (CLBP), recurrent low back pain (RLBP), and acute low back pain (ALBP). Systematic review. All selected studies were case-control studies. A systematic literature search was conducted in the databases PubMed and Web of Science. Only full texts of original studies regarding structural alterations (atrophy, fat infiltration, and fiber type distribution) in lumbar muscles of patients with non-specific LBP compared to healthy controls were included. All included articles were scored on methodological quality. Fifteen studies were found eligible after screening title, abstract, and full text for inclusion and exclusion criteria. In CLBP, moderate evidence of atrophy was found in the multifidus; whereas, results in the paraspinal and the erector spinae muscle remain inconclusive. Also moderate evidence occurred in RLBP and ALBP, where no atrophy was shown in any lumbar muscle. Conflicting results were seen in undefined LBP groups. Results concerning fat infiltration were inconsistent in CLBP. On the other hand, there is moderate evidence in RLBP that fat infiltration does not occur, although a larger muscle fat index was found in the erector spinae, multifidus, and paraspinal muscles, reflecting an increased relative amount of intramuscular lipids in RLBP. However, no studies were found investigating fat infiltration in ALBP. Restricted evidence indicates no abnormalities in fiber type in the paraspinal muscles in CLBP. No studies have examined fiber type in ALBP and RLBP. Lack of clarity concerning patient definitions, exact LBP symptoms, and applied methods. The results indicate atrophy in CLBP in the multifidus and paraspinal muscles but not in the erector spinae. No atrophy was shown in RLBP and ALBP. Fat infiltration did not occur in RLBP, but results in CLBP were inconsistent. No abnormalities in fiber type in the paraspinal muscles were found in CLBP. Low back pain, non-specific, chronic, recurrent, acute, muscle structure, fat infiltration, cross-sectional area, fiber type, review.

Sport-Specific Training Targeting the Proximal Segments and Throwing Velocity in Collegiate Throwing Athletes

PubMed Central

Palmer, Thomas; Uhl, Timothy L.; Howell, Dana; Hewett, Timothy E.; Viele, Kert; Mattacola, Carl G.

2015-01-01

Context The ability to generate, absorb, and transmit forces through the proximal segments of the pelvis, spine, and trunk has been proposed to influence sport performance, yet traditional training techniques targeting the proximal segments have had limited success improving sport-specific performance. Objective To investigate the effects of a traditional endurance-training program and a sport-specific power-training program targeting the muscles that support the proximal segments and throwing velocity. Design Randomized controlled clinical trial. Setting University research laboratory and gymnasium. Patients or Other Participants A total of 46 (age = 20 ± 1.3 years, height = 175.7 ± 8.7 cm) healthy National Collegiate Athletic Association Division III female softball (n = 17) and male baseball (n = 29) players. Intervention(s) Blocked stratification for sex and position was used to randomly assign participants to 1 of 2 training groups for 7 weeks: a traditional endurance-training group (ET group; n = 21) or a power-stability–training group (PS group; n = 25). Mean Outcome Measure(s) The change score in peak throwing velocity (km/h) normalized for body weight (BW; kilograms) and change score in tests that challenge the muscles of the proximal segments normalized for BW (kilograms). We used 2-tailed independent-samples t tests to compare differences between the change scores. Results The peak throwing velocity (ET group = 0.01 ± 0.1 km/h/kg of BW, PS group = 0.08 ± 0.03 km/h/kg of BW; P < .001) and muscle power outputs for the chop (ET group = 0.22 ± 0.91 W/kg of BW, PS group = 1.3 ± 0.91 W/kg of BW; P < .001) and lift (ET group = 0.59 ± 0.67 W/kg of BW, PS group = 1.4 ± 0.87 W/kg of BW; P < .001) tests were higher at postintervention in the PT than in the ET group. Conclusions An improvement in throwing velocity occurred simultaneously with measures of muscular endurance and power after a sport-specific training regimen targeting the proximal segments. PMID:25844854

Calcineurin is not involved in some mitochondrial enzyme adaptations to endurance exercise training in rat skeletal muscle.

PubMed

Terada, Shin; Nakagawa, Hisashi; Nakamura, Yoshio; Muraoka, Isao

2003-09-01

The purpose of this study was to test the hypothesis that calcineurin, a calcium-dependent protein phosphatase recently implicated in the signaling of skeletal muscle hypertrophy and fiber type conversion, is required to induce some mitochondrial enzyme adaptations to endurance exercise training in skeletal muscle. Three- to four-week-old male Sprague-Dawley rats with an initial body weight ranging from 45 to 55 g were used in this study. The rats were randomly assigned to groups injected with either a specific calcineurin inhibitor, cyclosporin A (CsA), (group CI) or vehicle (group VI). CsA was subcutaneously injected into the rats at a rate of 50 mg.kg(-1) body weight per day for 10 days. The CI and VI groups were further assigned to sedentary (SED) or exercise training (EX) groups. In the EX group, the rats were trained for 10 days (90 min.day(-1), approximately 14-20 m.min(-1), 10% grade). The citrate synthase (CS) activities in the soleus and plantaris muscles of the EX group rats were significantly higher than those of the SED group rats ( p<0.001). Furthermore, 3-beta-hydroxyacyl-CoA dehydrogenase (3-HAD) activities in the soleus and plantaris muscles were significantly higher in the EX group rats than in the SED group rats ( p<0.001). However, there were no significant differences in CS and 3-HAD activities between the VI and CI groups. The interactions between CsA injection and exercise training were not statistically significant in any of the parameters. These results may suggest that calcineurin is not involved in some mitochondrial enzyme adaptations to endurance exercise training.

Pasture-feeding of Charolais steers influences skeletal muscle metabolism and gene expression.

PubMed

Cassar-Malek, I; Jurie, C; Bernard, C; Barnola, I; Micol, D; Hocquette, J-F

2009-10-01

Extensive beef production systems on pasture are promoted to improve animal welfare and beef quality. This study aimed to compare the influence on muscle characteristics of two management approaches representative of intensive and extensive production systems. One group of 6 Charolais steers was fed maize-silage indoors and another group of 6 Charolais steers grazed on pasture. Activities of enzymes representative of glycolytic and oxidative (Isocitrate dehydrogenase [ICDH], citrate synthase [CS], hydroxyacyl-CoA dehydrogenase [HAD]) muscle metabolism were assessed in Rectus abdominis (RA) and Semitendinosus (ST) muscles. Activities of oxidative enzymes ICDH, CS and HAD were higher in muscles from grazing animals demonstrating a plasticity of muscle metabolism according to the production and feeding system. Gene expression profiling in RA and ST muscles was performed on both production groups using a multi-tissue bovine cDNA repertoire. Variance analysis showed an effect of the muscle type and of the production system on gene expression (P<0.001). A list of the 212 most variable genes according to the production system was established, of which 149 genes corresponded to identified genes. They were classified according to their gene function annotation mainly in the "protein metabolism and modification", "signal transduction", "cell cycle", "developmental processes" and "muscle contraction" biological processes. Selenoprotein W was found to be underexpressed in pasture-fed animals and could be proposed as a putative gene marker of the grass-based system. In conclusion, enzyme-specific adaptations and gene expression modifications were observed in response to the production system and some of them could be candidates for grazing or grass-feeding traceability.

Nitrosative stress in human skeletal muscle attenuated by exercise countermeasure after chronic disuse.

PubMed

Salanova, Michele; Schiffl, Gudrun; Gutsmann, Martina; Felsenberg, Dieter; Furlan, Sandra; Volpe, Pompeo; Clarke, Andrew; Blottner, Dieter

2013-01-01

Activity-induced nitric oxide (NO) imbalance and "nitrosative stress" are proposed mechanisms of disrupted Ca(2+) homeostasis in atrophic skeletal muscle. We thus mapped S-nitrosylated (SNO) functional muscle proteins in healthy male subjects in a long-term bed rest study (BBR2-2 Study) without and with exercise as countermeasure in order to assess (i) the negative effects of chronic muscle disuse by nitrosative stress, (ii) to test for possible attenuation by exercise countermeasure in bed rest and (iii) to identify new NO target proteins. Muscle biopsies from calf soleus and hip vastus lateralis were harvested at start (Pre) and at end (End) from a bed rest disuse control group (CTR, n=9) and two bed rest resistive exercise groups either without (RE, n=7) or with superimposed vibration stimuli (RVE, n=7). At subcellular compartments, strong anti-SNO-Cys immunofluorescence patterns in control muscle fibers after bed rest returned to baseline following vibration exercise. Total SNO-protein levels, Nrf-2 gene expression and nucleocytoplasmic shuttling were changed to varying degrees in all groups. Excess SNO-protein levels of specific calcium release/uptake proteins (SNO-RyR1, -SERCA1 and -PMCA) and of contractile myosin heavy chains seen in biopsy samples of chronically disused skeletal muscle were largely reduced by vibration exercise. We also identified NOS1 as a novel NO target in human skeletal muscle controlled by activity driven auto-nitrosylation mechanisms. Our findings suggest that aberrant levels of functional SNO-proteins represent signatures of uncontrolled nitrosative stress management in disused human skeletal muscle that can be offset by exercise as countermeasure.

Muscle thickness measurements of the lower trapezius with rehabilitative ultrasound imaging are confounded by scapular dyskinesis.

PubMed

Seitz, Amee L; Baxter, Caralyn J; Benya, Kristen

2015-08-01

Alterations in scapular muscle activity have been theorized to contribute to abnormal scapular motion and shoulder pain, but pose challenges to quantify in the clinic. Rehabilitative Ultrasound Imaging (RUSI) has proved useful identifying dysfunction of lumbar regional stabilizing muscle activity, specifically contractile behavior. Although, recent examinations of scapular stabilizing trapezius muscle function using RUSI did not detect alterations individuals with shoulder pain or differences in muscle thickness between varying external loads in asymptomatic individuals, a potential confounder to prior results, scapular dyskinesis has not been controlled. It is unknown if dyskinesis alters scapular muscle thickness during activation measured with RUSI. Thus, the purpose of this study was to compare change in scapular muscle thickness between individuals with and without scapular dyskinesis. Thirty-nine asymptomatic adults with (n = 19) and without (n = 20) scapular dyskinesis, defined with a reliable and validated method, participated. Two separate ultrasound images of the serratus anterior (SA) and lower trapezius (LT) were captured under two randomized conditions, rest and isometric contraction against gravity, and saved for blinded measurement. Change in thickness with contraction was calculated and expressed as a percentage. The dyskinesis group demonstrated a greater increase (p = 0.005) in LT thickness with the isometric contraction than the group without (mean difference = 31.6%; 95%CI = 10.3, 53.0). No differences in SA or resting thickness of either muscle were found between groups. The presence of scapular dyskinesis alters thickness changes of the lower trapezius during activation. Furthermore, potential underlying reasons beyond muscle contractile behavior must be considered. Copyright © 2015 Elsevier Ltd. All rights reserved.

The angle-torque-relationship of the subtalar pronators and supinators in male athletes: A comparative study of soccer and handball players.

PubMed

Hagen, Marco; Asholt, Johannes; Lemke, Martin; Lahner, Matthias

2016-05-18

It is currently unclear how participation in different sports affects the angle-specific subtalar pronator and supinator muscle strength and pronator-to-supinator strength ratio (PSR). Based on the hypothesis that both differences sport-related patterns of play and foot-ground interaction may lead to sport-specific muscle adaptations, this study compared the angle specific pronator and supinator strength capacity of handball and soccer players. Eighteen healthy male handball and 19 soccer players performed maximum isometric voluntary isometric contractions using a custom-made testing apparatus. Peak pronator (PPT) and supinator torques (PST), pronator and supinator strength curves (normalised to the peak torque across all joint angles) and PSR were measured in five anatomical joint angles across the active subtalar range of motion (ROM). All analysed parameters were dependent on the subtalar joint angle. The ANOVA revealed significant `joint angle' × `group' interactions on PPT, pronator strength curves and PSR. No group differences were found for active subtalar ROM. In previously uninjured handball and soccer athletes, there were intrinsic differences in angle-specific subtalar pronator muscle strength. The lower PSR, which was found in the most supinated angle, can be seen as a risk factor for sustaining an ankle sprain.

The effects of pilates on balance, mobility and strength in patients with multiple sclerosis.

PubMed

Guclu-Gunduz, Arzu; Citaker, Seyit; Irkec, Ceyla; Nazliel, Bijen; Batur-Caglayan, Hale Zeynep

2014-01-01

Although there are evidences as to Pilates developing dynamic balance, muscle strength and flexibility in healthy people, evidences related to its effects on Multiple Sclerosis patients are insufficient. The aims of this study were to investigate the effects of Pilates on balance, mobility, and strength in ambulatory patients with Multiple Sclerosis. Twenty six patients were divided into two groups as experimental (n = 18) and control (n = 8) groups for an 8-week treatment program. The experimental group underwent Pilates and the control group did abdominal breathing and active extremity exercises at home. Balance and mobility were measured with Berg Balance Scale and Timed up and go test, upper and lower muscle strength with hand-held dynamometer. Confidence in balance skills while performing daily activities was evaluated with Activities Specific Balance Confidence Scale. Improvements were observed in balance, mobility, and upper and lower extremity muscle strength in the Pilates group (p < 0.05). No significant differences in any outcome measures were observed in the control group (p > 0.05). Due to its structure which is made up of balance and strengthening exercises, Pilates training may develop balance, mobility and muscle strength of MS patients. For this reason, we think that, Pilates exercises which are appropriate for the disability level of the patient may be suggested.

Muscle Volume Increases Following 16 Weeks of Resistive Exercise Training with the Advanced Resistive Exercise Device (ARED) and Free Weights

NASA Technical Reports Server (NTRS)

Nash, R. E.; Loehr, J. A.; Lee, S. M. C.; English, K. L.; Evans, H.; Smith, S. A.; Hagan, R. D.

2009-01-01

Space flight-induced muscle atrophy, particularly in the postural and locomotorymuscles, may impair task performance during long-duration space missions and planetary exploration. High intensity free weight (FW) resistive exercise training has been shown to prevent atrophy during bed rest, a space flight analog. NASA developed the Advanced Resistive Exercise Device (ARED) to simulate the characteristics of FW exercise (i.e. constant mass, inertial force) and to be used as a countermeasure during International Space Station (ISS) missions. PURPOSE: To compare the efficacy of ARED and FW training to induce hypertrophy in specific muscle groups in ambulatory subjects prior to deploying ARED on the ISS. METHODS: Twenty untrained subjects were assigned to either the ARED (8 males, 3 females) or FW (6 males, 3 females) group and participated in a periodizedtraining protocol consisting of squat (SQ), heel raise (HR), and deadlift(DL) exercises 3 d wk-1 for 16 wks. SQ, HR, and DL muscle strength (1RM) was measured before, after 8 wks, and after 16 wks of training to prescribe exercise and measure strength changes. Muscle volume of the vastigroup (V), hamstring group (H), hip adductor group (ADD), medial gastrocnemius(MG), lateral gastrocnemius(LG), and deep posterior muscles including soleus(DP) was measured using MRI pre-and post-training. Consecutive cross-sectional images (8 mm slices with a 2 mm gap) were analyzed and summed. Anatomical references insured that the same muscle sections were analyzed pre-and post-training. Two-way repeated measures ANOVAs (p<0.05) were used to test for differences in muscle strength and volume between training devices. RESULTS: SQ, HR, and DL 1RM increased in both FW (SQ: 49+/-6%, HR: 12+/-2%, DL: 23+/-4%) and ARED (SQ: 31+/-4%, HR: 18+/-2%, DL: 23+/-3%) groups. Both groups increased muscle volume in the V (FW: 13+/-2%, ARED: 10+/-2%), H (FW: 3+/-1%, ARED: 3+/-1 %), ADD (FW: 15=/-2%, ARED: 10+/-1%), LG (FW: 7+/-2%, ARED: 4+/-1%), MG (FW: 7+/-2%, ARED: 5+/-2%), and DP (FW: 2+/-1%; ARED: 2+/-1%) after training. There were no between group differences in muscle strength or volume. CONCLUSIONS: The increase in muscle volume and strength following ARED training is not different than FW training. With the training effects similar to FW and a 600 lb load capacity, ARED likely will protect against muscle atrophy in microgravity.

Resistance Training Enhances Skeletal Muscle Innervation Without Modifying the Number of Satellite Cells or their Myofiber Association in Obese Older Adults.

PubMed

Messi, María Laura; Li, Tao; Wang, Zhong-Min; Marsh, Anthony P; Nicklas, Barbara; Delbono, Osvaldo

2016-10-01

Studies in humans and animal models provide compelling evidence for age-related skeletal muscle denervation, which may contribute to muscle fiber atrophy and loss. Skeletal muscle denervation seems relentless; however, long-term, high-intensity physical activity appears to promote muscle reinnervation. Whether 5-month resistance training (RT) enhances skeletal muscle innervation in obese older adults is unknown. This study found that neural cell-adhesion molecule, NCAM+ muscle area decreased with RT and was inversely correlated with muscle strength. NCAM1 and RUNX1 gene transcripts significantly decreased with the intervention. Type I and type II fiber grouping in the vastus lateralis did not change significantly but increases in leg press and knee extensor strength inversely correlated with type I, but not with type II, fiber grouping. RT did not modify the total number of satellite cells, their number per area, or the number associated with specific fiber subtypes or innervated/denervated fibers. Our results suggest that RT has a beneficial impact on skeletal innervation, even when started late in life by sedentary obese older adults. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of 17-day spaceflight on knee extensor muscle function and size

NASA Technical Reports Server (NTRS)

Tesch, Per A.; Berg, Hans E.; Bring, Daniel; Evans, Harlan J.; LeBlanc, Adrian D.

2005-01-01

It is generally held that space travelers experience muscle dysfunction and atrophy during exposure to microgravity. However, observations are scarce and reports somewhat inconsistent with regard to the time course, specificity and magnitude of such changes. Hence, we examined four male astronauts (group mean approximately 43 years, 86 kg and 183 cm) before and after a 17-day spaceflight (Space Transport System-78). Knee extensor muscle function was measured during maximal bilateral voluntary isometric and iso-inertial concentric, and eccentric actions. Cross-sectional area (CSA) of the knee extensor and flexor, and gluteal muscle groups was assessed by means of magnetic resonance imaging. The decrease in strength (P<0.05) across different muscle actions after spaceflight amounted to 10%. Eight ambulatory men, examined on two occasions 20 days apart, showed unchanged (P>0.05) muscle strength. CSA of the knee extensor and gluteal muscles, each decreased (P<0.05) by 8%. Knee flexor muscle CSA showed no significant (P>0.05) change. The magnitude of these changes concord with earlier results from ground-based studies of similar duration. The results of this study, however, do contrast with the findings of no decrease in maximal voluntary ankle plantar flexor force previously reported in the same crew.

Patterning the dorsal longitudinal flight muscles (DLM) of Drosophila: insights from the ablation of larval scaffolds

NASA Technical Reports Server (NTRS)

Fernandes, J. J.; Keshishian, H.

1996-01-01

The six Dorsal Longitudinal flight Muscles (DLMs) of Drosophila develop from three larval muscles that persist into metamorphosis and serve as scaffolds for the formation of the adult fibers. We have examined the effect of muscle scaffold ablation on the development of DLMs during metamorphosis. Using markers that are specific to muscle and myoblasts we show that in response to the ablation, myoblasts which would normally fuse with the larval muscle, fuse with each other instead, to generate the adult fibers in the appropriate regions of the thorax. The development of these de novo DLMs is delayed and is reflected in the delayed expression of erect wing, a transcription factor thought to control differentiation events associated with myoblast fusion. The newly arising muscles express the appropriate adult-specific Actin isoform (88F), indicating that they have the correct muscle identity. However, there are frequent errors in the number of muscle fibers generated. Ablation of the larval scaffolds for the DLMs has revealed an underlying potential of the DLM myoblasts to initiate de novo myogenesis in a manner that resembles the mode of formation of the Dorso-Ventral Muscles, DVMs, which are the other group of indirect flight muscles. Therefore, it appears that the use of larval scaffolds is a superimposition on a commonly used mechanism of myogenesis in Drosophila. Our results show that the role of the persistent larval muscles in muscle patterning involves the partitioning of DLM myoblasts, and in doing so, they regulate formation of the correct number of DLM fibers.

Compound muscle action potential duration in critical illness neuromyopathy.

PubMed

Kramer, Christopher L; Boon, Andrea J; Harper, C Michel; Goodman, Brent P

2018-03-01

We sought to determine the specificity of compound muscle action potential (CMAP) durations and amplitudes in a large critical illness neuromyopathy (CINM) cohort relative to controls with other neuromuscular conditions. Fifty-eight patients with CINM who had been seen over a 17-year period were retrospectively studied. Electrodiagnostic findings of the CINM cohort were compared with patients with axonal peripheral neuropathy and myopathy due to other causes. Mean CMAP durations were prolonged, and mean CMAP amplitudes were severely reduced both proximally and distally in all nerves studied in the CINM cohort relative to the control groups. The specificity of prolonged CMAP durations for CINM approached 100% if they were encountered in more than 1 nerve. Prolonged, low-amplitude CMAPs occur more frequently and with greater severity in CINM patients than in neuromuscular controls with myopathy and axonal neuropathy and are highly specific for the diagnosis of CINM. Muscle Nerve 57: 395-400, 2018. © 2017 Wiley Periodicals, Inc.

Changes in Locomotor Muscle Activity After Treadmill Training in Subjects With Incomplete Spinal Cord Injury

PubMed Central

Gorassini, Monica A.; Norton, Jonathan A.; Nevett-Duchcherer, Jennifer; Roy, Francois D.; Yang, Jaynie F.

2009-01-01

Intensive treadmill training after incomplete spinal cord injury can improve functional walking abilities. To determine the changes in muscle activation patterns that are associated with improvements in walking, we measured the electromyography (EMG) of leg muscles in 17 individuals with incomplete spinal cord injury during similar walking conditions both before and after training. Specific differences were observed between subjects that eventually gained functional improvements in overground walking (responders), compared with subjects where treadmill training was ineffective (nonresponders). Although both groups developed a more regular and less clonic EMG pattern on the treadmill, it was only the tibialis anterior and hamstring muscles in the responders that displayed increases in EMG activation. Likewise, only the responders demonstrated decreases in burst duration and cocontraction of proximal (hamstrings and quadriceps) muscle activity. Surprisingly, the proximal muscle activity in the responders, unlike nonresponders, was three- to fourfold greater than that in uninjured control subjects walking at similar speeds and level of body weight support, suggesting that the ability to modify muscle activation patterns after injury may predict the ability of subjects to further compensate in response to motor training. In summary, increases in the amount and decreases in the duration of EMG activity of specific muscles are associated with functional recovery of walking skills after treadmill training in subjects that are able to modify muscle activity patterns following incomplete spinal cord injury. PMID:19073799

Muscle-damaging exercise 48 h prior to a maximal incremental exercise treadmill test reduces time to exhaustion: is it time to reconsider our pretest procedures?

PubMed

Rose Chrismas, Bryna Catherine; Taylor, Lee; Siegler, Jason Charles; Midgley, Adrian Wayne

2017-01-01

Pretest guidelines typically stipulate that no exercise should be performed 48 h prior to a maximal incremental exercise [Formula: see text] test. However, no study has specifically investigated if this timescale alters key outcome variables associated with [Formula: see text]. Twenty apparently healthy males split into two equal groups performed [Formula: see text] during three visits (visits 1 - [Formula: see text] EXP1 , 2 - [Formula: see text] EXP2 and 4 - [Formula: see text] EXP3 ). The experimental group only, performed muscle-damaging exercise during visit 3. From [Formula: see text] EXP2 to [Formula: see text] EXP3 average time to exhaustion (TTE) decreased by 45 s (9%) (p < 0.01), maximum blood lactate decreased by 1.2 mmol/L (11%) (p = 0.03), and perceived readiness decreased by 8 mm (18%) (p = 0.01). There were no changes in any [Formula: see text] variables in the control group (p ≥ 0.37). Performing [Formula: see text] 48 h following muscle-damaging exercise impairs specific, but not all, physiological outcome variables.

[Exercise therapy as a therapeutic concept].

PubMed

Reer, R; Ziegler, M; Braumann, K-M

2005-08-01

Lack of exercise is a primary cause for today's level of morbidity and mortality in the Western world. Thus, exercise as a therapeutic modality has an important role. Beneficial effects of exercise have been extensively documented, specifically in primary and secondary prevention of coronary heart disease (CHD), diabetes mellitus, hypertension, disorders of fat metabolism, heart insufficiency, cancer, etc. A regular (at least 3 x per week) endurance training program of 30-40 min duration at an intensity of 65-70% of VO(2)max involving large muscle groups is recommended. The specific exercise activity can also positively affect individuals with orthopedic disease patterns, i.e., osteoporosis, back pain, postoperative rehabilitation, etc. Endurance strength training in the form of sequential training involving approx. 8-10 different exercises for the most important muscle groups 2 x per week is a suitable exercise therapy. One to three sets with 8-12 repetitions per exercise should be performed until volitional exhaustion of the trained muscle groups among healthy adults and 15-20 repetitions among older and cardiac patients. Apart from a positive effect on the locomotor system, this type of strength training has positive effects on CHD, diabetes mellitus, and cancer.

Comparison of In-Season-Specific Resistance vs. A Regular Throwing Training Program on Throwing Velocity, Anthropometry, and Power Performance in Elite Handball Players.

PubMed

Hermassi, Souhail; van den Tillaar, Roland; Khlifa, Riadh; Chelly, Mohamed Souhaiel; Chamari, Karim

2015-08-01

The purpose of this study was to compare the effect of a specific resistance training program (throwing movement with a medicine ball) with that of regular training (throwing with regular balls) on ball velocity, anthropometry, maximal upper-body strength, and power. Thirty-four elite male team handball players (age: 18 ± 0.5 years, body mass: 80.6 ± 5.5 kg, height: 1.80 ± 5.1 m, body fat: 13.4 ± 0.6%) were randomly assigned to 1 of the 3 groups: control (n = 10), resistance training group (n = 12), or regular throwing training group (n = 12). Over the 8-week in season, the athletes performed 3 times per week according to an assigned training program alongside their normal team handball training. One repetition maximum (1RM) bench press and 1RM pullover scores assessed maximal arm strength. Anthropometry was assessed by body mass, fat percentage, and muscle volumes of upper body. Handball throwing velocity was measured by a standing throw, a throw with run, and a jump throw. Power was measured by measuring total distance thrown by a 3-kg medicine ball overhead throw. Throwing ball velocity, maximal strength, power, and muscle volume increases for the specific resistance training group after the 8 weeks of training, whereas only maximal strength, muscle volume and power and in the jump throw increases were found for the regular throwing training group. No significant changes for the control group were found. The current findings suggest that elite male handball players can improve ball velocity, anthropometrics, maximal upper-body strength, and power during the competition season by implementing a medicine ball throwing program.

Aging Induces Changes in the Somatic Nerve and Postsynaptic Component without Any Alterations in Skeletal Muscles Morphology and Capacity to Carry Load of Wistar Rats

PubMed Central

Krause Neto, Walter; Silva, Wellington de Assis; Ciena, Adriano P.; de Souza, Romeu R.; Anaruma, Carlos A.; Gama, Eliane F.

2017-01-01

The present study aimed to analyze the morphology of the peripheral nerve, postsynaptic compartment, skeletal muscles and weight-bearing capacity of Wistar rats at specific ages. Twenty rats were divided into groups: 10 months-old (ADULT) and 24 months-old (OLD). After euthanasia, we prepared and analyzed the tibial nerve using transmission electron microscopy and the soleus and plantaris muscles for cytofluorescence and histochemistry. For the comparison of the results between groups we used dependent and independent Student's t-test with level of significance set at p ≤ 0.05. For the tibial nerve, the OLD group presented the following alterations compared to the ADULT group: larger area and diameter of both myelinated fibers and axons, smaller area occupied by myelinated and unmyelinated axons, lower numerical density of myelinated fibers, and fewer myelinated fibers with normal morphology. Both aged soleus and plantaris end-plate showed greater total perimeter, stained perimeter, total area and stained area compared to ADULT group (p < 0.05). Yet, aged soleus end-plate presented greater dispersion than ADULT samples (p < 0.05). For the morphology of soleus and plantaris muscles, density of the interstitial volume was greater in the OLD group (p < 0.05). No statistical difference was found between groups in the weight-bearing tests. The results of the present study demonstrated that the aging process induces changes in the peripheral nerve and postsynaptic compartment without any change in skeletal muscles and ability to carry load in Wistar rats. PMID:29326543

Early-phase musculoskeletal adaptations to different levels of eccentric resistance after 8 weeks of lower body training.

PubMed

English, Kirk L; Loehr, James A; Lee, Stuart M C; Smith, Scott M

2014-11-01

Eccentric muscle actions are important to the development of muscle mass and strength and may affect bone mineral density (BMD). This study's purpose was to determine the relative effectiveness of five different eccentric:concentric load ratios to increase musculoskeletal parameters during early adaptations to resistance training. Forty male subjects performed a supine leg press and calf press training program 3 days week(-1) for 8 weeks. Subjects were matched for pre-training leg press 1-repetition maximum strength (1-RM) and randomly assigned to one of five training groups. Concentric training load (% 1-RM) was constant across groups, but within groups, eccentric load was 0, 33, 66, 100, or 138% of concentric load. Muscle mass (dual energy X-ray absorptiometry; DXA), strength (1-RM), and BMD (DXA) were measured pre- and post-training. Markers of bone metabolism were assessed pre-, mid- and post-training. The increase in leg press 1-RM in the 138% group (20 ± 4%) was significantly greater (P < 0.05) than the 0% (8 ± 3%), 33% (8 ± 5%) and 66% (8 ± 4%) groups, but not the 100% group (13 ± 6 %; P = 0.15). All groups, except the 0% group, increased calf press 1-RM (P < 0.05). Leg lean mass and greater trochanter BMD were increased only in the 138% group (P < 0.05). Early-phase adaptations to eccentric overload training include increases in muscle mass and site-specific increases in BMD and muscle strength which are not present or are less with traditional and eccentric underload training. Eccentric overload provides a robust musculoskeletal stimulus that may benefit bedridden patients, individuals recovering from injury or illness, and astronauts during spaceflight.

Role of transplanted bone marrow cells in development of rotator cuff muscle fatty degeneration in mice.

PubMed

Klomps, Lawrence V; Zomorodi, Naseem; Kim, H Mike

2017-12-01

Rotator cuff muscle fatty degeneration after a chronic tendon tear is an irreversible pathologic change associated with poor clinical outcomes of tendon repair, and its exact pathogenesis remains unknown. We sought to investigate the role of transplanted bone marrow cells in the development of fatty degeneration, specifically in adipocyte accumulation, using a mouse model. Fourteen mice were divided into 2 bone marrow chimeric animal groups: bone marrow transplantation (BMT) group and reverse BMT group. For the BMT group, C57BL/6J wild-type mice underwent whole body irradiation followed by BMT into the retro-orbital sinus from green fluorescent protein (GFP)-transgenic donor mice. For the reverse BMT group, GFP-transgenic mice received BMT from C57BL/6J wild-type donor mice after irradiation. The supraspinatus tendon, infraspinatus tendon, and suprascapular nerve were surgically transected 3 weeks after transplantation. The rotator cuff muscles were harvested 13 weeks after transplantation for histologic analysis and GFP immunohistochemistry. On histologic examination, both groups showed substantial fatty degeneration, fibrosis, and atrophy of the cuff muscles. The BMT group showed no noticeable GFP immunostaining, whereas the reverse BMT group showed significantly stronger GFP staining in most adipocytes (P < .001). However, both groups also showed that a small number of adipocytes originated from transplanted bone marrow cells. A small number of myocytes showed a large cytoplasmic lipid vacuole resembling adipocytes. This study's findings suggest that most adipocytes in fatty degeneration of the rotator cuff muscles originate from sources other than bone marrow-derived stem cells, and there may be more than 1 source for the adipocytes. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Effects of Pilates and yoga in patients with chronic neck pain: A sonographic study.

PubMed

Uluğ, Naime; Yılmaz, Öznur Tunca; Kara, Murat; Özçakar, Levent

2018-01-10

Various studies have shown the efficacy of conventional isometric, Pilates and yoga exercises. However, data on the effects and comparison of these specific exercises on the cervical muscle morphology are insufficient or lacking. To investigate the effects of different exercise treatments on neck muscles in patients with chronic neck pain. A randomized study. Fifty-six patients with chronic neck pain were randomized into 3 groups as follows: Pilates group (n = 20), yoga group (n = 18) and isometric group (n = 18). Demographics and background information were recorded. The thickness and cross-sectional area of neck muscles were evaluated by ultrasound imaging. Cervical motions were measured with a goniometer. Pain severity was evaluated with the McGill Pain Scale, disability with the Neck Disability Index, quality of life with the Nottingham Health Profile, and emotional status with the Beck Depression Inventory. In addition to a conventional physio-therapy programme, 15 sessions of physical therapy, including hot pack, ultrasound, and transcutaneous electrical nerve stimulation (TENS), were provided to all patients. All groups performed the exercises for 6 weeks. The aforementioned assessments were performed before and 6 weeks after the treatment. Although pain, disability, depression and quality of life improved similarly within all groups (all p < 0.05), muscle thickness values as regards the semispinalis capitis were increased only in the Pilates group (p = 0.022). The lack of complex (progressive resistive) exercise treatment protocols, short treatment duration and partial supervision. All 3 types of exercise had favourable effects on pain and functional scores, but no differences were found among the groups, except for the Pilates group, in which the semispinalis capitis muscle increased in thickness.

Effect of pelvic floor muscle training compared with watchful waiting in older women with symptomatic mild pelvic organ prolapse: randomised controlled trial in primary care.

PubMed

Wiegersma, Marian; Panman, Chantal M C R; Kollen, Boudewijn J; Berger, Marjolein Y; Lisman-Van Leeuwen, Yvonne; Dekker, Janny H

2014-12-22

To compare the effects of pelvic floor muscle training and watchful waiting on pelvic floor symptoms in a primary care population of women aged 55 years and over with symptomatic mild pelvic organ prolapse. Randomised controlled trial. Dutch primary care. Women aged 55 years or over with symptomatic mild prolapse (leading edge above the hymen) were identified by screening. Exclusion criteria were current prolapse treatment or treatment in the previous year, malignancy of pelvic organs, current treatment for another gynaecological disorder, severe/terminal illness, impaired mobility, cognitive impairment, and insufficient command of the Dutch language. Pelvic floor muscle training versus watchful waiting. The primary outcome was change in bladder, bowel, and pelvic floor symptoms measured with the Pelvic Floor Distress Inventory-20 (PFDI-20), three months after the start of treatment. Secondary outcomes were changes in condition specific and general quality of life, sexual function, degree of prolapse, pelvic floor muscle function, and patients' perceived change in symptoms. Of the 287 women who were randomised to pelvic floor muscle training (n=145) or watchful waiting (n=142), 250 (87%) completed follow-up. Participants in the intervention group improved by (on average) 9.1 (95% confidence interval 2.8 to 15.4) points more on the PFDI-20 than did participants in the watchful waiting group (P=0.005). Of women in the pelvic floor muscle training group, 57% (82/145) reported an improvement in overall symptoms from the start of the study compared with 13% (18/142) in the watchful waiting group (P<0.001). Other secondary outcomes showed no significant difference between the groups. Although pelvic floor muscle training led to a significantly greater improvement in PFDI-20 score, the difference between the groups was below the presumed level of clinical relevance (15 points). Nevertheless, 57% of the participants in the intervention group reported an improvement of overall symptoms. More studies are needed to identify factors related to success of pelvic floor muscle training and to investigate long term effects.Trial registration Dutch Trial Register (www.trialregister.nl) identifier: NTR2047. © Wiegersma et al 2014.

Knee joint stabilization therapy in patients with osteoarthritis of the knee: a randomized, controlled trial.

PubMed

Knoop, J; Dekker, J; van der Leeden, M; van der Esch, M; Thorstensson, C A; Gerritsen, M; Voorneman, R E; Peter, W F; de Rooij, M; Romviel, S; Lems, W F; Roorda, L D; Steultjens, M P M

2013-08-01

To investigate whether an exercise program, initially focusing on knee stabilization and subsequently on muscle strength and performance of daily activities is more effective than an exercise program focusing on muscle strength and performance of daily activities only, in reducing activity limitations in patients with knee osteoarthritis (OA) and instability of the knee joint. A single-blind, randomized, controlled trial involving 159 knee OA patients with self-reported and/or biomechanically assessed knee instability, randomly assigned to two treatment groups. Both groups received a supervised exercise program for 12 weeks, consisting of muscle strengthening exercises and training of daily activities, but only in the experimental group specific knee joint stabilization training was provided. Outcome measures included activity limitations (Western Ontario and McMaster Universities Osteoarthritis Index - WOMAC physical function, primary outcome), pain, global perceived effect and knee stability. Both treatment groups demonstrated large (∼20-40%) and clinically relevant reductions in activity limitations, pain and knee instability, which were sustained 6 months post-treatment. No differences in effectiveness between experimental and control treatment were found on WOMAC physical function (B (95% confidence interval - CI) = -0.01 (-2.58 to 2.57)) or secondary outcome measures, except for a higher global perceived effect in the experimental group (P = 0.04). Both exercise programs were highly effective in reducing activity limitations and pain and restoring knee stability in knee OA patients with instability of the knee. In knee OA patients suffering from knee instability, specific knee joint stabilization training, in addition to muscle strengthening and functional exercises, does not seem to have any additional value. Dutch Trial Register (NTR) registration number: NTR1475. Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Soluble Milk Protein Supplementation with Moderate Physical Activity Improves Locomotion Function in Aging Rats.

PubMed

Lafoux, Aude; Baudry, Charlotte; Bonhomme, Cécile; Le Ruyet, Pascale; Huchet, Corinne

2016-01-01

Aging is associated with a loss of muscle mass and functional capacity. Present study was designed to compare the impact of specific dairy proteins on muscular function with or without a low-intensity physical activity program on a treadmill in an aged rat model. We investigated the effects of nutritional supplementation, five days a week over a 2-month period with a slow digestible protein, casein or fast digestible proteins, whey or soluble milk protein, on strength and locomotor parameters in sedentary or active aged Wistar RjHan rats (17-19 months of age). An extensive gait analysis was performed before and after protein supplementation. After two months of protein administration and activity program, muscle force was evaluated using a grip test, spontaneous activity using an open-field and muscular mass by specific muscle sampling. When aged rats were supplemented with proteins without exercise, only minor effects of different diets on muscle mass and locomotion were observed: higher muscle mass in the casein group and improvement of stride frequencies with soluble milk protein. By contrast, supplementation with soluble milk protein just after physical activity was more effective at improving overall skeletal muscle function in old rats compared to casein. For active old rats supplemented with soluble milk protein, an increase in locomotor activity in the open field and an enhancement of static and dynamic gait parameters compared to active groups supplemented with casein or whey were observed without any differences in muscle mass and forelimb strength. These results suggest that consumption of soluble milk protein as a bolus immediately after a low intensity physical activity may be a suitable nutritional intervention to prevent decline in locomotion in aged rats and strengthen the interest to analyze the longitudinal aspect of locomotion in aged rodents.

The role of active muscle mass in determining the magnitude of peripheral fatigue during dynamic exercise.

PubMed

Rossman, Matthew J; Garten, Ryan S; Venturelli, Massimo; Amann, Markus; Richardson, Russell S

2014-06-15

Greater peripheral quadriceps fatigue at the voluntary termination of single-leg knee-extensor exercise (KE), compared with whole-body cycling, has been attributed to confining group III and IV skeletal muscle afferent feedback to a small muscle mass, enabling the central nervous system (CNS) to tolerate greater peripheral fatigue. However, as task specificity and vastly differing systemic challenges may have complicated this interpretation, eight males were studied during constant workload trials to exhaustion at 85% of peak workload during single-leg and double-leg KE. It was hypothesized that because of the smaller muscle mass engaged during single-leg KE, a greater magnitude of peripheral quadriceps fatigue would be present at exhaustion. Vastus lateralis integrated electromyogram (iEMG) signal relative to the first minute of exercise, preexercise to postexercise maximal voluntary contractions (MVCs) of the quadriceps, and twitch-force evoked by supramaximal magnetic femoral nerve stimulation (Qtw,pot) quantified peripheral quadriceps fatigue. Trials performed with single-leg KE (8.1 ± 1.2 min; 45 ± 4 W) resulted in significantly greater peripheral quadriceps fatigue than double-leg KE (10 ± 1.3 min; 83 ± 7 W), as documented by changes in the iEMG signal (147 ± 24 vs. 85 ± 13%), MVC (-25 ± 3 vs. -12 ± 3%), and Qtw,pot (-44 ± 6 vs. -33 ± 7%), for single-leg and double-leg KE, respectively. Therefore, avoiding concerns over task specificity and cardiorespiratory limitations, this study reveals that a reduction in muscle mass permits the development of greater peripheral muscle fatigue and supports the concept that the CNS tolerates a greater magnitude of peripheral fatigue when the source of group III/IV afferent feedback is limited to a small muscle mass.

Soluble Milk Protein Supplementation with Moderate Physical Activity Improves Locomotion Function in Aging Rats

PubMed Central

Lafoux, Aude; Baudry, Charlotte; Bonhomme, Cécile; Le Ruyet, Pascale; Huchet, Corinne

2016-01-01

Aging is associated with a loss of muscle mass and functional capacity. Present study was designed to compare the impact of specific dairy proteins on muscular function with or without a low-intensity physical activity program on a treadmill in an aged rat model. We investigated the effects of nutritional supplementation, five days a week over a 2-month period with a slow digestible protein, casein or fast digestible proteins, whey or soluble milk protein, on strength and locomotor parameters in sedentary or active aged Wistar RjHan rats (17–19 months of age). An extensive gait analysis was performed before and after protein supplementation. After two months of protein administration and activity program, muscle force was evaluated using a grip test, spontaneous activity using an open-field and muscular mass by specific muscle sampling. When aged rats were supplemented with proteins without exercise, only minor effects of different diets on muscle mass and locomotion were observed: higher muscle mass in the casein group and improvement of stride frequencies with soluble milk protein. By contrast, supplementation with soluble milk protein just after physical activity was more effective at improving overall skeletal muscle function in old rats compared to casein. For active old rats supplemented with soluble milk protein, an increase in locomotor activity in the open field and an enhancement of static and dynamic gait parameters compared to active groups supplemented with casein or whey were observed without any differences in muscle mass and forelimb strength. These results suggest that consumption of soluble milk protein as a bolus immediately after a low intensity physical activity may be a suitable nutritional intervention to prevent decline in locomotion in aged rats and strengthen the interest to analyze the longitudinal aspect of locomotion in aged rodents. PMID:27973615

Fiber-type-specific sensitivities and phenotypic adaptations to dietary fat overload differentially impact fast- versus slow-twitch muscle contractile function in C57BL/6J mice.

PubMed

Ciapaite, Jolita; van den Berg, Sjoerd A; Houten, Sander M; Nicolay, Klaas; van Dijk, Ko Willems; Jeneson, Jeroen A

2015-02-01

High-fat diets (HFDs) have been shown to interfere with skeletal muscle energy metabolism and cause peripheral insulin resistance. However, understanding of HFD impact on skeletal muscle primary function, i.e., contractile performance, is limited. Male C57BL/6J mice were fed HFD containing lard (HFL) or palm oil (HFP), or low-fat diet (LFD) for 5weeks. Fast-twitch (FT) extensor digitorum longus (EDL) and slow-twitch (ST) soleus muscles were characterized with respect to contractile function and selected biochemical features. In FT EDL muscle, a 30%-50% increase in fatty acid (FA) content and doubling of long-chain acylcarnitine (C14-C18) content in response to HFL and HFP feeding were accompanied by increase in protein levels of peroxisome proliferator-activated receptor-γ coactivator-1α, mitochondrial oxidative phosphorylation complexes and acyl-CoA dehydrogenases involved in mitochondrial FA β-oxidation. Peak force of FT EDL twitch and tetanic contractions was unaltered, but the relaxation time (RT) of twitch contractions was 30% slower compared to LFD controls. The latter was caused by accumulation of lipid intermediates rather than changes in the expression levels of proteins involved in calcium handling. In ST soleus muscle, no evidence for lipid overload was found in any HFD group. However, particularly in HFP group, the peak force of twitch and tetanic contractions was reduced, but RT was faster than LFD controls. The latter was associated with a fast-to-slow shift in troponin T isoform expression. Taken together, these data highlight fiber-type-specific sensitivities and phenotypic adaptations to dietary lipid overload that differentially impact fast- versus slow-twitch skeletal muscle contractile function. Copyright © 2015 Elsevier Inc. All rights reserved.

Influence of racial origin and skeletal muscle properties on disease prevalence and physical performance.

PubMed

Suminski, Richard R; Mattern, Craig O; Devor, Steven T

2002-01-01

Skeletal muscle properties are related to disease (e.g. obesity) and physical performance. For example, a predominance of type I muscle fibres is associated with better performance in endurance sports and a lower risk of obesity. Disease and physical performance also differ among certain racial groups. African Americans are more likely than Caucasians to develop obesity, diabetes mellitus and hypertension. Empirical studies indicate that aerobic capacity is lower in African Americans than Caucasians. Because genetics is a partial determinant of skeletal muscle properties, it is reasonable to assume that skeletal muscle properties vary as a function of race. As such, genetically determined and race-specific skeletal muscle properties may partially explain racial disparities in disease and physical performance. However, additional research is needed in this area to enable the development of more definitive conclusions.

Higher medially-directed joint reaction forces are a characteristic of dysplastic hips: A comparative study using subject-specific musculoskeletal models.

PubMed

Harris, Michael D; MacWilliams, Bruce A; Bo Foreman, K; Peters, Christopher L; Weiss, Jeffrey A; Anderson, Andrew E

2017-03-21

Acetabular dysplasia is a known cause of hip osteoarthritis. In addition to abnormal anatomy, changes in kinematics, joint reaction forces (JRFs), and muscle forces could cause tissue damage to the cartilage and labrum, and may contribute to pain and fatigue. The objective of this study was to compare lower extremity joint angles, moments, hip JRFs and muscle forces during gait between patients with symptomatic acetabular dysplasia and healthy controls. Marker trajectories and ground reaction forces were measured in 10 dysplasia patients and 10 typically developing control subjects. A musculoskeletal model was scaled in OpenSim to each subject and subject-specific hip joint centers were determined using reconstructions from CT images. Joint kinematics and moments were calculated using inverse kinematics and inverse dynamics, respectively. Muscle forces and hip JRFs were estimated with static optimization. Inter-group differences were tested for statistical significance (p≤0.05) and large effect sizes (d≥0.8). Results demonstrated that dysplasia patients had higher medially directed JRFs. Joint angles and moments were mostly similar between the groups, but large inter-group effect sizes suggested some restriction in range of motion by patients at the hip and ankle. Higher medially-directed JRFs and inter-group differences in hip muscle forces likely stem from lateralization of the hip joint center in dysplastic patients. Joint force differences, combined with reductions in range of motion at the hip and ankle may also indicate compensatory strategies by patients with dysplasia to maintain joint stability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Higher Medially-directed Joint Reaction Forces are a Characteristic of Dysplastic Hips: A Comparative Study Using Subject-Specific Musculoskeletal Models

PubMed Central

Harris, Michael D.; MacWilliams, Bruce A.; Foreman, K. Bo; Peters, Christopher L.; Weiss, Jeffrey A.; Anderson, Andrew E.

2018-01-01

Acetabular dysplasia is a known cause of hip osteoarthritis. In addition to abnormal anatomy, changes in kinematics, joint reaction forces (JRFs), and muscle forces could cause tissue damage to the cartilage and labrum, and may contribute to pain and fatigue. The objective of this study was to compare lower extremity joint angles, moments, hip JRFs and muscle forces during gait between patients with symptomatic acetabular dysplasia and healthy controls. Marker trajectories and ground reaction forces were measured in 10 dysplasia patients and 10 typically developing control subjects. A musculoskeletal model was scaled in OpenSim to each subject and subject-specific hip joint centers were determined using reconstructions from CT images. Joint kinematics and moments were calculated using inverse kinematics and inverse dynamics, respectively. Muscle forces and hip JRFs were estimated with static optimization. Inter-group differences were tested for statistical significance (p≤0.05) and large effect sizes (d≥0.8). Results demonstrated that dysplasia patients had higher medially directed JRFs. Joint angles and moments were mostly similar between the groups, but large inter-group effect sizes suggested some restriction in range of motion by patients at the hip and ankle. Higher medially-directed JRFs and inter-group differences in hip muscle forces likely stem from lateralization of the hip joint center in dysplastic patients. Joint force differences, combined with reductions in range of motion at the hip and ankle may also indicate compensatory strategies by patients with dysplasia to maintain joint stability. PMID:28233552

Physical fitness assessment: an update.

PubMed

Wilder, Robert P; Greene, Jill Amanda; Winters, Kathryne L; Long, William B; Gubler, K; Edlich, Richard F

2006-01-01

The American College of Sports Medicine (ACSM) gives the following definition of health-related physical fitness: Physical fitness is defined as a set of attributes that people have or achieve that relates to the ability to perform physical activity. It is also characterized by (1) an ability to perform daily activities with vigor, and (2) a demonstration of traits and capacities that are associated with a low risk of premature development of hypokinetic diseases (e.g., those associated with physical inactivity). Information from an individual's health and medical records can be combined with information from physical fitness assessment to meet the specific health goals and rehabilitative needs of that individual. Attaining adequate informed consent from participants prior to exercise testing is mandatory because of ethical and legal considerations.A physical fitness assessment includes measures of body composition, cardiorespiratory endurance, muscular fitness, and musculoskeletal flexibility. The three common techniques for assessing body composition are hydrostatic weighing, and skinfold measurements, and anthropometric measurements. Cardiorespiratory endurance is a crucial component of physical fitness assessment because of its strong correlation with health and health risks. Maximal oxygen uptake (VO2max) is the traditionally accepted criterion for measuring cardiorespiratory endurance. Although maximal-effort tests must be used to measure VO2max, submaximal exercise can be used to estimate this value. Muscular fitness has historically been used to describe an individual's integrated status of muscular strength and muscular endurance. An individual's muscular strength is specific to a particular muscle or muscle group and refers to the maximal force (N or kg) that the muscle or muscle group can generate. Dynamic strength can be assessed by measuring the movement of an individual's body against an external load. Isokinetic testing may be performed by assessing the muscle tension generated throughout a range of motion at a constant angular velocity. The ability of a muscle group to perform repeated contractions over a specific period of time that is sufficient to cause fatigue is termed muscular endurance. Musculoskeletal flexibility evaluations focus on the joints and associated structures, ligaments, and muscles that cross the joints. The sit-and-reach test and the behind-the-back reach test satisfy many of the criteria for physical assessment of musculoskeletal flexibility. A physical fitness assessment must be integrated into all activities of daily living, as well as the physician's examination, to assess and promote health.

Pharmacological Inhibitors of the Proteosome in Atrophying Muscles

NASA Technical Reports Server (NTRS)

Goldberg, Alfred

1999-01-01

It is now clear that the marked loss of muscle mass that occurs with disuse, denervation or in many systemic diseases (cancer cachexia, sepsis, acidosis, various endocrine disorders) is due primarily to accelerated degradation of muscle proteins, especially myofibrillar components. Recent work primarily in Dr. Goldberg's laboratory had suggested that in these diverse conditions, the enhancement of muscle proteolysis results mainly from activation of the Ub-proteasome degradative pathway. In various experimental models of atrophy, rat muscles show a common series of changes indicative of activation of this pathway, including increases in MRNA for Ub and proteasome subunits, content of ubiquitinated proteins, and sensitivity to inhibitors of the proteasome. In order to understand the muscle atrophy seen in weightlessness, Dr. Goldberg's laboratory is collaborating with Dr. Baldwin in studies to define the changes in these parameters upon hind-limb suspension. Related experiments will explore the effects on this degradative system of exercise regimens and also of glucocorticoids, which are known to rise in space personnel and to promote muscle, especially in inactive muscles. The main goals will be: (A) to define the enzymatic changes leading to enhanced activity of the Ub-proteasome pathway in inactive muscles upon hind-limb suspension, and the effects on this system of exposure to glucocorticoids or exercise; and (B) to learn whether inhibitors of the Ub-proteasome pathway may be useful in retarding the excessive proteolysis in atrophying muscles. Using muscle extracts, Dr. Goldberg's group hopes to define the rate-limiting, enzymatic changes that lead to the accelerated Ub-conjugation and protein degradation. They have recently developed cell-free preparations from atrophying rat muscles, in which Ub-conjugation to muscle proteins is increased above control levels. Because these new preparations seem to reproduce the changes occurring in vivo, they will analyze in depth extracts from normal and atrophying muscles to compare the activities of the Ub-activating enzyme (El), the various LTh-carrier proteins (E2s), and Ub-protein ligases (E3s). Recent studies of other types of muscle wasting -suggest a very important role in muscle proteolysis of certain ubiquitination enzymes, E214k and E3-alpha(i.e. components of the "N-end pathway"). Future studies will focus in understanding their role and test whether they are in fact critical for muscle atrophy in vivo. Since weightlessness leads to a specific loss of contractile proteins and to a switching of myosin isotypes, Dr. Goldberg's group will attempt to identify the ubiquitination enzymes specifically involved in myosin degradation both in normal muscle and after hind-limb suspension.

The influence of altered working-side occlusal guidance on masticatory muscles and related jaw movement.

PubMed

Belser, U C; Hannam, A G

1985-03-01

The effect of four different occlusal situations (group function, canine guidance, working side occlusal interference, and hyperbalancing occlusal interference) on EMG activity in jaw elevator muscles and related mandibular movement was investigated on 12 subjects. With a computer-based system, EMG and displacement signals were collected simultaneously during specific functional (unilateral chewing) and parafunctional tasks (mandibular gliding movements and various tooth clenching efforts) and analyzed quantitatively. When a naturally acquired group function was temporarily and artificially changed into a dominant canine guidance, a significant general reduction of elevator muscle activity was observed when subjects exerted full isometric tooth-clenching efforts in a lateral mandibular position. The original muscular coordination pattern (relative contraction from muscle to muscle) remained unaltered during this test. With respect to unilateral chewing, no significant alterations in the activity or coordination of the muscles occurred when an artificial canine guidance was introduced. Introduction of a hyperbalancing occlusal contact caused significant alterations in muscle activity and coordination during maximal tooth clenching in a lateral mandibular position. A marked shift of temporal muscle EMG activity toward the side of the interference and unchanged bilateral activity of the two masseter muscles were observed. The results suggest that canine-protected occlusions do not significantly alter muscle activity during mastication but significantly reduce muscle activity during parafunctional clenching. They also suggest that non-working side contacts dramatically alter the distribution of muscle activity during parafunctional clenching, and that this redistribution may affect the nature of reaction forces at the temporomandibular joints.

Effective fiber hypertrophy in satellite cell-depleted skeletal muscle

PubMed Central

McCarthy, John J.; Mula, Jyothi; Miyazaki, Mitsunori; Erfani, Rod; Garrison, Kelcye; Farooqui, Amreen B.; Srikuea, Ratchakrit; Lawson, Benjamin A.; Grimes, Barry; Keller, Charles; Van Zant, Gary; Campbell, Kenneth S.; Esser, Karyn A.; Dupont-Versteegden, Esther E.; Peterson, Charlotte A.

2011-01-01

An important unresolved question in skeletal muscle plasticity is whether satellite cells are necessary for muscle fiber hypertrophy. To address this issue, a novel mouse strain (Pax7-DTA) was created which enabled the conditional ablation of >90% of satellite cells in mature skeletal muscle following tamoxifen administration. To test the hypothesis that satellite cells are necessary for skeletal muscle hypertrophy, the plantaris muscle of adult Pax7-DTA mice was subjected to mechanical overload by surgical removal of the synergist muscle. Following two weeks of overload, satellite cell-depleted muscle showed the same increases in muscle mass (approximately twofold) and fiber cross-sectional area with hypertrophy as observed in the vehicle-treated group. The typical increase in myonuclei with hypertrophy was absent in satellite cell-depleted fibers, resulting in expansion of the myonuclear domain. Consistent with lack of nuclear addition to enlarged fibers, long-term BrdU labeling showed a significant reduction in the number of BrdU-positive myonuclei in satellite cell-depleted muscle compared with vehicle-treated muscle. Single fiber functional analyses showed no difference in specific force, Ca2+ sensitivity, rate of cross-bridge cycling and cooperativity between hypertrophied fibers from vehicle and tamoxifen-treated groups. Although a small component of the hypertrophic response, both fiber hyperplasia and regeneration were significantly blunted following satellite cell depletion, indicating a distinct requirement for satellite cells during these processes. These results provide convincing evidence that skeletal muscle fibers are capable of mounting a robust hypertrophic response to mechanical overload that is not dependent on satellite cells. PMID:21828094

Postural synergies associated with a stepping task.

PubMed

Mercer, V S; Sahrmann, S A

1999-12-01

Synergistic relationships among multiple muscle components are thought to exist to simplify control of posture and movement. The purpose of this study was to examine the extent to which children, young adults, and older adults exhibit consistent sequences of postural muscle activation when lifting the right foot onto a step from a standing position. Twenty subjects without known impairments of the neuromuscular system (10 male, 10 female) in each of 3 age groups--children (8-12 years), young adults (25-35 years), and older adults (65-73 years)--participated. A pressure switch taped to the subject's right foot was used to determine movement onset and offset. Latencies of muscle activation were determined using surface electromyography. A preferred postural synergy was defined as the sequence of postural muscle activation observed during the majority of trials for each subject. Mean movement times did not differ among age groups. Although the left tibialis anterior (TA) muscle was the first of the postural muscles activated in 93% of the trials, subjects displayed considerable variability in the subsequent order of postural muscle activation. Across subjects, a total of 14 different preferred postural synergies were observed. Age groups did not differ in the number of different synergies. Early TA activation may reflect biomechanical constraints of the stepping task, producing forward displacement of the center of mass over the changing base of support. The fact that subjects of all ages were quite variable in the specific sequences of muscles activated subsequent to the TA suggests that, for this type of task, therapists should not focus their interventions on facilitating execution of particular synergy patterns.

Bilateral differences in muscle fascicle architecture are not related to the preferred leg in jumping athletes.

PubMed

Aeles, Jeroen; Lenchant, Sietske; Vanlommel, Liesbeth; Vanwanseele, Benedicte

2017-07-01

In many sports, athletes have a preferred leg for sport-specific tasks, such as jumping, which leads to strength differences between both legs, yet the underlying changes in force-generating mechanical properties of the muscle remain unknown. The purpose of this study was to investigate whether the muscle architecture of the medial gastrocnemius (MG) is different between both legs in well-trained jumping athletes and untrained individuals. In addition, we investigated the effect of two ankle joint positions on ultrasound muscle architecture measurements. Muscle architecture of both legs was measured in 16 athletes and 11 untrained individuals at two ankle joint angles: one with the ankle joint in a tendon slack length (TSL) angle and one in a 90° angle. Fascicle lengths and pennation angles at TSL were not different between the preferred and non-preferred legs in either group. The comparison between groups showed no difference in fascicle length, but greater pennation angles were found in the athletes (21.7° ± 0.5°) compared to the untrained individuals (19.8° ± 0.6°). Analyses of the muscle architecture at a 90° angle yielded different results, mainly in the comparison between groups. These results provide only partial support for the notion of training-induced changes in muscle architecture as only differences in pennation angles were found between athletes and untrained individuals. Furthermore, our results provide support to the recommendation to take into account the tension-length relationship and to measure muscle architecture at individually determined tendon slack joint angles.

High-frequency resistance training is not more effective than low-frequency resistance training in increasing muscle mass and strength in well-trained men.

PubMed

Gomes, Gederson K; Franco, Cristiane M; Nunes, Paulo Ricardo P; Orsatti, Fábio L

2018-02-27

We studied the effects of two different weekly frequency resistance training (RT) protocols over eight weeks on muscle strength and muscle hypertrophy in well-trained men. Twenty-three subjects (age: 26.2±4.2 years; RT experience: 6.9±3.1 years) were randomly allocated into the two groups: low frequency (LFRT, n = 12) or high frequency (HFRT, n = 11). The LFRT performed a split-body routine, training each specific muscle group once a week. The HFRT performed a total-body routine, training all muscle groups every session. Both groups performed the same number of sets (10-15 sets) and exercises (1-2 exercise) per week, 8-12 repetitions maximum (70-80% of 1RM), five times per week. Muscle strength (bench press and squat 1RM) and lean tissue mass (dual-energy x-ray absorptiometry) were assessed prior to and at the end of the study. Results showed that both groups improved (p<0.001) muscle strength [LFRT and HFRT: bench press = 5.6 kg (95% Confidence Interval (CI): 1.9 - 9.4) and 9.7 kg (95%CI: 4.6 - 14.9) and squat = 8.0 kg (95%CI: 2.7 - 13.2) and 12.0 kg (95%CI: 5.1 - 18.1), respectively] and lean tissue mass (p = 0.007) [LFRT and HFRT: total body lean mass = 0.5 kg (95%CI: 0.0 - 1.1) and 0.8 kg (95%CI: 0.0 - 1.6), respectively] with no difference between groups (bench press, p = 0.168; squat, p = 0.312 and total body lean mass, p = 0.619). Thus, HFRT and LFRT are similar overload strategies for promoting muscular adaptation in well-trained subjects when the sets and intensity are equated per week.

Group I Paks support muscle regeneration and counteract cancer-associated muscle atrophy.

PubMed

Cerquone Perpetuini, Andrea; Re Cecconi, Andrea David; Chiappa, Michela; Martinelli, Giulia Benedetta; Fuoco, Claudia; Desiderio, Giovanni; Castagnoli, Luisa; Gargioli, Cesare; Piccirillo, Rosanna; Cesareni, Gianni

2018-05-21

Skeletal muscle is characterized by an efficient regeneration potential that is often impaired during myopathies. Understanding the molecular players involved in muscle homeostasis and regeneration could help to find new therapies against muscle degenerative disorders. Previous studies revealed that the Ser/Thr kinase p21 protein-activated kinase 1 (Pak1) was specifically down-regulated in the atrophying gastrocnemius of Yoshida hepatoma-bearing rats. In this study, we evaluated the role of group I Paks during cancer-related atrophy and muscle regeneration. We examined Pak1 expression levels in the mouse Tibialis Anterior muscles during cancer cachexia induced by grafting colon adenocarcinoma C26 cells and in vitro by dexamethasone treatment. We investigated whether the overexpression of Pak1 counteracts muscle wasting in C26-bearing mice and in vitro also during interleukin-6 (IL6)-induced or dexamethasone-induced C2C12 atrophy. Moreover, we analysed the involvement of group I Paks on myogenic differentiation in vivo and in vitro using the group I chemical inhibitor IPA-3. We found that Pak1 expression levels are reduced during cancer-induced cachexia in the Tibialis Anterior muscles of colon adenocarcinoma C26-bearing mice and in vitro during dexamethasone-induced myotube atrophy. Electroporation of muscles of C26-bearing mice with plasmids directing the synthesis of PAK1 preserves fiber size in cachectic muscles by restraining the expression of atrogin-1 and MuRF1 and possibly by inducing myogenin expression. Consistently, the overexpression of PAK1 reduces the dexamethasone-induced expression of MuRF1 in myotubes and increases the phospho-FOXO3/FOXO3 ratio. Interestingly, the ectopic expression of PAK1 counteracts atrophy in vitro by restraining the IL6-Stat3 signalling pathway measured in luciferase-based assays and by reducing rates of protein degradation in atrophying myotubes exposed to IL6. On the other hand, we observed that the inhibition of group I Paks has no effect on myotube atrophy in vitro and is associated with impaired muscle regeneration in vivo and in vitro. In fact, we found that mice treated with the group I inhibitor IPA-3 display a delayed recovery from cardiotoxin-induced muscle injury. This is consistent with in vitro experiments showing that IPA-3 impairs myogenin expression and myotube formation in vessel-associated myogenic progenitors, C2C12 myoblasts, and satellite cells. Finally, we observed that IPA-3 reduces p38α/β phosphorylation that is required to proceed through various stages of satellite cells differentiation: activation, asymmetric division, and ultimately myotube formation. Our data provide novel evidence that is consistent with group I Paks playing a central role in the regulation of muscle homeostasis, atrophy and myogenesis. © 2018 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

Muscle stretching exercises and resistance training in fibromyalgia: which is better? A three-arm randomized controlled trial.

PubMed

Assumpção, Ana; Matsutani, Luciana A; Yuan, Susan L; Santo, Adriana S; Sauer, Juliana; Mango, Pamela; Marques, Amelia P

2017-11-29

Exercise therapy is an effective component of fibromyalgia (FM) treatment. However, it is important to know the effects and specificities of the different types of exercise: muscle stretching and resistance training. To verify and compare the effectiveness of muscle stretching exercise and resistance training for symptoms and quality of life in FM patients. Randomized controlled trial. Physical therapy service, FM outpatient clinic. Forty-four women with FM (79 screened). Patients were randomly allocated into a stretching group (n=14), resistance group (n=16), and control group (n=14). Pain was assessed using the visual analog scale, pain threshold using a Fischer dolorimeter, FM symptoms using the Fibromyalgia Impact Questionnaire (FIQ), and quality of life using the Medical Outcomes Study 36-item Short- Form Health Survey (SF-36). The three intervention groups continued with usual medical treatment. In addition, the stretching and resistance groups performed two different exercise programs twice a week for 12 weeks. After treatment, the stretching group showed the highest SF-36 physical functioning score (p=0.01) and the lowest bodily pain score (p=0.01). The resistance group had the lowest FIQ depression score (p=0.02). The control group had the highest score for FIQ morning tiredness and stiffness, and the lowest score for SF-36 vitality. In clinical analyses, the stretching group had significant improvement in quality of life for all SF-36 domains, and the resistance group had significant improvement in FM symptoms and in quality of life for SF-36 domains of physical functioning, vitality, social function, emotional role, and mental health. Muscle stretching exercise was the most effective modality in improving quality of life, especially with regard to physical functioning and pain, and resistance training was the most effective modality in reducing depression. The trial included a control group and two intervention groups, both of which received exercise programs created specifically for patients with FM. In clinical practice, we suggest including both of these modalities in an exercise therapy program for FM.

Volume and fat infiltration of spino-pelvic musculature in adults with spinal deformity

PubMed Central

Moal, Bertrand; Bronsard, Nicolas; Raya, José G; Vital, Jean Marc; Schwab, Frank; Skalli, Wafa; Lafage, Virginie

2015-01-01

AIM: To investigate fat infiltration and volume of spino-pelvic muscles in adults spinal deformity (ASD) with magnetic resonance imaging (MRI) and 3D reconstructions. METHODS: Nineteen female ASD patients (mean age 60 ± 13) were included prospectively and consecutively and had T1-weighted Turbo Spin Echo sequence MRIs with Dixon method from the proximal tibia up to T12 vertebra. The Dixon method permitted to evaluate the proportion of fat inside each muscle (fat-water ratio). In order to investigate the accuracy of the Dixon method for estimating fat vs water, the same MRI acquisition was performed on phantoms of four vials composed of different proportion of fat vs water. With Muscl’X software, 3D reconstructions of 17 muscles or group of muscles were obtained identifying the muscle’s contour on a limited number of axial images [Deformation of parametric specific objects (DPSO) Method]. Musclar volume (Vmuscle), infiltrated fat volume (Vfat) and percentage of fat infiltration [Pfat, calculated as follow: Pfat = 100 × (Vfat/Vmuscle)] were characterized by extensor or flexor function respectively for the spine, hip and knee and theirs relationship with demographic data were investigated. RESULTS: Phantom acquisition demonstrated a non linear relation between Dixon fat-water ratio and the real fat-water ratio. In order to correct the Dixon fat-water ratio, the non linear relation was approximated with a polynomial function of degree three using the phantom acquisition. On average, Pfat was 13.3% ± 5.3%. Muscles from the spinal extensor group had a Pfat significantly greater than the other muscles groups, and the largest variability (Pfat = 31.9% ± 13.8%, P < 0.001). Muscles from the hip extensor group ranked 2nd in terms of Pfat (14% ± 8%), and were significantly greater than those of the knee extensor (P = 0.030). Muscles from the knee extensor group demonstrated the least Pfat (12% ± 8%). They were also the only group with a significant correlation between Vmuscle and Pfat (r = -0.741, P < 0.001), however this correlation was lacking in the other groups. No correlation was found between the Vmuscle total and age or body mass index. Except for the spine flexors, Pfat was correlated with age. Vmuscle and Vfat distributions demonstrated that muscular degeneration impacted the spinal extensors most. CONCLUSION: Mechanisms of fat infiltration are not similar among the muscle groups. Degeneration impacted the spinal and hip extensors most, key muscles of the sagittal alignment. PMID:26495250

Increased fat deposition in injured skeletal muscle is regulated by sex-specific hormones

PubMed Central

McHale, Matthew J.; Sarwar, Zaheer U.; Cardenas, Damon P.; Porter, Laurel; Salinas, Anna S.; Michalek, Joel E.; McManus, Linda M.

2012-01-01

Sex differences in skeletal muscle regeneration are controversial; comparisons of regenerative events between sexes have not been rigorously defined in severe injury models. We comprehensively quantified inflammation and muscle regeneration between sexes and manipulated sex-specific hormones to determine effects on regeneration. Cardiotoxin injury was induced in intact, castrated and ovariectomized female and male mice; ovariectomized mice were replaced with low- or high-dose 17-β estradiol (E2) or progesterone (P4). Extent of injury was comparable between intact mice, but females were more efficient in removal of necrotic debris, despite similar tissue levels of inflammatory cells and chemokines. Myofiber size during regeneration was equivalent between intact mice and after castration or ovariectomy (OVX) but was decreased (P < 0.001) in ovariectomized mice with high-dose E2 replacement. Intermuscular adipocytes were absent in uninjured muscle, whereas adipocyte area was increased among regenerated myofibers in all groups. Interestingly, intermuscular fat was greater (P = 0.03) in intact females at day 14 compared with intact males. Furthermore, castration increased (P = 0.01) and OVX decreased adipocyte accumulation. After OVX, E2, but not P4, replacement decreased (P ≤ 0.03) fat accumulation. In conclusion, sex-dependent differences in regeneration consisted of more efficient removal of necrosis and increased fat deposition in females with similar injury, inflammation, and regenerated myofiber size; high-dose E2 decreased myofiber size and fat deposition. Adipocyte accumulation in regenerating muscle was influenced by sex-specific hormones. Recovery following muscle injury was different between males and females, and sex-specific hormones contributed to these differences, suggesting that sex-specific treatments could be beneficial after injury. PMID:22116509

Bioelectrical impedance analysis for diagnosing sarcopenia and cachexia: what are we really estimating?

PubMed

Gonzalez, Maria Cristina; Heymsfield, Steven B

2017-04-01

As reference methods are not available for identifying low skeletal muscle mass in clinical practice, the European Group on Sarcopenia in Older People the Asian Working Group for Sarcopenia and the International Consensus for Cancer Cachexia guidelines accept bioelectrical impedance analysis (BIA) as an option for sarcopenia and cachexia assessment. Using different BIA equations, several components that represent 'muscularity' can be assessed. Total skeletal muscle mass or appendicular skeletal muscle mass normalized in relation to height (skeletal muscle mass index or appendicular skeletal muscle index, respectively) is the most common term used in the consensus. These terms are similar, but they should not be used as synonymous. Both terms can be used to define sarcopenia, but adequate equations and cut-off values should be used according to the studied population. However, there is a disagreement between the sarcopenia definition assessed by using BIA from the European Group on Sarcopenia in Older People and Cachexia Consensus, and this can lead to an overestimation of sarcopenia and, consequently, cachexia. An effort should be made to standardize the terminology employed by the Societies to define low muscularity and sarcopenia by using BIA. Future validation studies may show the need for specific cut-off values for each population using this method. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

[Age-related features of neuromuscular function in rats with hyperthyroidism].

PubMed

Nerush, P O; Makiĭ, Ie A; Rodyns'kyĭ, O H

2001-01-01

Studied features of functioning of nervous-muscular system at white rats of two age groups: preadolescent (5 weeks) and puberal (24 weeks), in conditions experimental hyperthyroidism (HT). It is established, that in conditions HT at action of the raised concentration thyroxine characteristics of excitation gastrocnemius muscles essentially changed at irritation of a sciatic nerve in groups preadolescent and puberal animals. In all age groups in conditions HT increase of a threshold of excitation gastrocnemius muscles is marked at indirect stimulation and decrease at direct stimulation; also in all age groups in conditions HT reduction of time chronaxy muscles is fixed, both at direct, and at indirect irritation. At preadolescent animals, as against puberal in conditions HT at action of the raised concentration thyroxine on nervous-muscular system it is not revealed authentic change of the latent period and amplitude of potential of action (PA). The conclusion is made, that in conditions HT change of a threshold of excitation and chronaxy gastrocnemius muscles both at direct, and at indirect irritation do not carry age specificity and have an identical orientation, both at preadolescent, and at puberal rats. At preadolescent animals in conditions HT, as against puberal the parameter of amplitude and latent period PA authentically did not change, that can testify to smaller sensitivity of the caused answers gastrocnemius muscles to the raised concentration thyroxine, probably, by virtue of immaturity peripheral neuromotor the device.

Specific Diurnal EMG Activity Pattern Observed in Occlusal Collapse Patients: Relationship between Diurnal Bruxism and Tooth Loss Progression

PubMed Central

Kawakami, Shigehisa; Kumazaki, Yohei; Manda, Yosuke; Oki, Kazuhiro; Minagi, Shogo

2014-01-01

Aim The role of parafunctional masticatory muscle activity in tooth loss has not been fully clarified. This study aimed to reveal the characteristic activity of masseter muscles in bite collapse patients while awake and asleep. Materials and Methods Six progressive bite collapse patients (PBC group), six age- and gender-matched control subjects (MC group), and six young control subjects (YC group) were enrolled. Electromyograms (EMG) of the masseter muscles were continuously recorded with an ambulatory EMG recorder while patients were awake and asleep. Diurnal and nocturnal parafunctional EMG activity was classified as phasic, tonic, or mixed using an EMG threshold of 20% maximal voluntary clenching. Results Highly extended diurnal phasic activity was observed only in the PBC group. The three groups had significantly different mean diurnal phasic episodes per hour, with 13.29±7.18 per hour in the PBC group, 0.95±0.97 per hour in the MC group, and 0.87±0.98 per hour in the YC group (p<0.01). ROC curve analysis suggested that the number of diurnal phasic episodes might be used to predict bite collapsing tooth loss. Conclusion Extensive bite loss might be related to diurnal masticatory muscle parafunction but not to parafunction during sleep. Clinical Relevance: Scientific rationale for study Although mandibular parafunction has been implicated in stomatognathic system breakdown, a causal relationship has not been established because scientific modalities to evaluate parafunctional activity have been lacking. Principal findings This study used a newly developed EMG recording system that evaluates masseter muscle activity throughout the day. Our results challenge the stereotypical idea of nocturnal bruxism as a strong destructive force. We found that diurnal phasic masticatory muscle activity was most characteristic in patients with progressive bite collapse. Practical implications The incidence of diurnal phasic contractions could be used for the prognostic evaluation of stomatognathic system stability. PMID:25010348

Age- and stage-dependent variations of muscle-specific gene expression in brown trout Salmo trutta L.

PubMed

Churova, Maria V; Meshcheryakova, Olga V; Ruchev, Mikhail; Nemova, Nina N

2017-09-01

This study was conducted to characterize the features of muscle-specific genes expression during development of brown trout Salmo trutta inhabiting the river Krivoy ruchey (Kola Peninsula, Russia). Gene expression levels of myogenic regulatory factors (MRFs - MyoD1 paralogs (MyoD1a, MyoD1b, MyoD1c), Myf5, myogenin), myostatin paralogs (MSTN-1a, MSTN-1b, MSTN-2a), fast skeletal myosin heavy chain (MyHC) were measured in the white muscles of brown trout parr of ages 0+ (under-yearling), 1+ (yearling) and 2+ (two year old) and smolts of age 2+. Multidirectional changes in MyoD1 and MSTN paralogs expression along with myogenin, Myf 5 and MyHC expression levels in white muscles in parr of trout with age were revealed. The expression of MyoD1c, myogenin, MSTN-2a was the highest in 0+ parr and then decreased. MyoD1a/b expression levels didn't differ between age groups. The simultaneous elevation of MyHC, Myf5, MSTN-1a, and MSTN-1b was found in trout yearlings. In smolts, expression levels of MSTN paralogs, MyHC, Myf5, MyoD1a was lower than in parr. But in contrast, the MyoD1c and myogenin mRNA levels was higher in smolts. The study revealed that there are definite patterns in simultaneous muscle-specific genes expression in age groups of parr and smolts. As MyoD and MSTN paralogs expression changed differently in dependence on age and stage, it was suggested that paralogs of the same gene complementarily control myogenesis during development. Copyright © 2017 Elsevier Inc. All rights reserved.

Corticospinal excitability of the ankle extensor muscles is enhanced in ballet dancers.

PubMed

Saito, Sakiko; Obata, Hiroki; Endoh, Takashi; Kuno-Mizumura, Mayumi; Nakazawa, Kimitaka

2014-09-01

We tested the corticospinal excitability of the soleus muscle in ballet dancers to clarify whether the presumed long-term repetition of the specific plantarflexion results in changes of excitability in this neural pathway. We compared motor evoked potentials of the soleus muscle at rest and during isometric contraction of the plantar flexors in dancers and non-dancers. The amplitudes of motor evoked potentials elicited by transcranial magnetic stimulation during contraction were examined against the background electromyographic activity. A regression line was calculated for each subject. Results showed that the slope of the regression line is significantly greater in the dancer group than in the control group, suggesting that the corticospinal tract of ballet dancers has adapted to long-term repetition of plantarflexion in daily ballet training.

How do deltoid muscle moment arms change after reverse total shoulder arthroplasty?

PubMed

Walker, David R; Struk, Aimee M; Matsuki, Keisuke; Wright, Thomas W; Banks, Scott A

2016-04-01

Although many advantages of reverse total shoulder arthroplasty (RTSA) have been demonstrated, a variety of complications indicate there is much to learn about how RTSA modifies normal shoulder function. This study used a subject-specific computational model driven by in vivo kinematic data to assess how RTSA affects deltoid muscle moment arms after surgery. A subject-specific 12 degree-of-freedom musculoskeletal model was used to analyze the shoulders of 26 individuals (14 RTSA and 12 normal). The model was modified from the work of Holzbaur to directly input 6 degree-of-freedom humeral and scapular kinematics obtained using fluoroscopy. The moment arms of the anterior, lateral, and posterior aspects of the deltoid were significantly different when RTSA and normal cohorts were compared at different abduction angles. Anterior and lateral deltoid moment arms were significantly larger in the RTSA group at the initial elevation of the arm. The posterior deltoid was significantly larger at maximum elevation. There was large intersubject variability within the RTSA group. Placement of implant components during RTSA can directly affect the geometric relationship between the humerus and scapula and the muscle moment arms in the RTSA shoulder. RTSA shoulders maintain the same anterior and posterior deltoid muscle moment-arm patterns as healthy shoulders but show much greater intersubject variation and larger moment-arm magnitudes. These observations provide a basis for determining optimal implant configuration and surgical placement to maximize RTSA function in a patient-specific manner. Published by Elsevier Inc.

Musculotendon and fascicle strains in anterior and posterior neck muscles during whiplash injury.

PubMed

Vasavada, Anita N; Brault, John R; Siegmund, Gunter P

2007-04-01

A biomechanical neck model combined with subject-specific kinematic and electromyographic data were used to calculate neck muscle strains during whiplash. To calculate the musculotendon and fascicle strains during whiplash and to compare these strains to published muscle injury thresholds. Previous work has shown potentially injurious musculotendon strains in sternocleidomastoid (SCM) during whiplash, but neither the musculotendon strains in posterior cervical muscles nor the fascicle strains in either muscle group have been examined. Experimental human subject data from rear-end automobile impacts were integrated with a biomechanical model of the neck musculoskeletal system. Subject-specific head kinematic data were imposed on the model, and neck musculotendon and fascicle strains and strain rates were computed. Electromyographic data from the sternocleidomastoid and the posterior cervical muscles were compared with strain data to determine which muscles were being eccentrically contracted. SCM experienced lengthening during the retraction phase of head/neck kinematics, whereas the posterior muscles (splenius capitis [SPL], semispinalis capitis [SEMI], and trapezius [TRAP]) lengthened during the rebound phase. Peak SCM fascicle lengthening strains averaged (+/-SD) 4% (+/-3%) for the subvolumes attached to the mastoid process and 7% (+/-5%) for the subvolume attached to the occiput. Posteriorly, peak fascicle strains were 21% (+/-14%) for SPL, 18% (+/-16%) for SEMI, and 5% (+/-4%) for TRAP, with SPL strains significantly greater than calculated in SCM or TRAP. Fascicle strains were, on average, 1.2 to 2.3 times greater than musculotendon strains. SCM and posterior muscle activity occurred during intervals of muscle fascicle lengthening. The cervical muscle strains induced during a rear-end impact exceed the previously-reported injury threshold for a single stretch of active muscle. Further, the larger strains experienced by extensor muscles are consistent with clinical reports of pain primarily in the posterior cervical region following rear-end impacts.

Analysis of EMG patterns of control subjects and subjects with ACL deficiency during an unanticipated walking cut task.

PubMed

Houck, Jeff R; Wilding, Gregory E; Gupta, Resmi; De Haven, Kenneth E; Maloney, Mike

2007-04-01

The purpose of this study was to describe the muscle activation patterns of the vastus lateralis (VL), medial hamstrings (MH) and lateral hamstrings (LH) associated with subjects that were anterior cruciate ligament (ACL) deficient and controls. A total of 54 subjects participated in this study including 25 ACL deficient subjects subdivided into copers (n=9) and non-copers (n=16) using clinical criteria. Muscle activation patterns were recorded at 1000 Hz during an unanticipated side step cut task. The root mean square processed data (time constant 11 ms) were ensemble averaged from 20% of stance before heel strike to toe off. Using the first five harmonics of the Fourier Coefficients as features, muscle activation patterns were divided using a cluster analysis algorithm. A majority (76-93%) of control subjects used three muscle activation patterns for each muscle. The coper group preferentially used a particular VL and MH activation pattern >2 times more frequently than controls. The non-coper group also preferentially used a MH activation pattern >2 times more frequently than controls and utilized a unique MH and LH activation pattern, distinct from the copers and controls. Specific muscle activation patterns distinguish subsets of subjects that are healthy and injured, suggesting possible patterns of muscle activation that contribute to coping status.

Effects of two different specific neck exercise interventions on palmitoylethanolamide and stearoylethanolamide concentrations in the interstitium of the trapezius muscle in women with chronic neck shoulder pain.

PubMed

Ghafouri, Nazdar; Ghafouri, Bijar; Fowler, Christopher J; Larsson, Britt; Turkina, Maria V; Karlsson, Linn; Gerdle, Björn

2014-08-01

Chronic neck/shoulder pain (CNSP) is one of the most common pain conditions. The understanding of mechanisms, including the peripheral balance between nociceptive and antinociceptive processes, is incomplete. N-acylethanolamines (NAEs) are a class of endogenous compounds that regulate inflammation and pain. The aim of this study was to investigate the levels of two NAEs: the peroxisome proliferator-activated receptor type-α ligand palmitoylethanolamide (PEA) and stearoylethanolamide (SEA) in the muscle interstitium of the trapezius muscle in women with CNSP randomized to two different neck specific training programs and in a healthy pain-free control group (CON). Fifty-seven women with CNSP were randomized to strength + stretch or stretch alone exercise programs. Twenty-nine subjects underwent microdialysis procedure before and after 4-6 months of exercise. Twenty-four CON subjects underwent microdialysis procedure before and after 4-6 months without any intervention in between. Microdialysate samples were collected from the trapezius muscle and analyzed by mass spectrometry for PEA and SEA levels. PEA and SEA levels were significantly higher in CNSP patients compared with CON. PEA was significantly higher in CNSP than in CON after both training programs. SEA was significantly higher in CNSP than in CON after stretch alone but not after strength + stretch training. A significant positive correlation was found between changes in pain intensity and in SEA levels in the strength + stretch group, but not in the stretch alone group. Our results indicate that exercise interventions differentially affect the levels of the bioactive lipids PEA and SEA in the interstitium of the trapezius muscle in women with CNSP. Wiley Periodicals, Inc.

Specific force of the vastus lateralis in adults with achondroplasia.

PubMed

Sims, David T; Onambélé-Pearson, Gladys L; Burden, Adrian; Payton, Carl; Morse, Christopher I

2018-03-01

Achondroplasia is a clinical condition defined by shorter stature and disproportionate limb length. Force production in able-bodied individuals (controls) is proportional to muscle size, but given the disproportionate nature of achondroplasia, normalizing to anatomical cross-sectional area (ACSA) is inappropriate. The aim of this study was to assess specific force of the vastus lateralis (VL) in 10 adults with achondroplasia (22 ± 3 yr) and 18 sex-matched controls (22 ± 2 yr). Isometric torque (iMVCτ) of the dominant knee extensors (KE) and in vivo measures of VL muscle architecture, volume, activation, and patella tendon moment arm were used to calculate VL physiological CSA (PCSA), fascicle force, and specific force in both groups. Achondroplasic muscle volume was 53% smaller than controls (284 ± 36 vs. 604 ± 102 cm 3 , P < 0.001). KE iMVCτ was 63% lower in achondroplasia compared with controls (95 ± 24 vs. 256 ± 47 N⋅m, P < 0.001). Activation and moment arm length were similar between groups ( P > 0.05), but coactivation of bicep femoris of achondroplasic subjects was 70% more than controls (43 ± 20 vs. 13 ± 5%, P < 0.001). Achondroplasic subjects had 58% less PCSA (43 ± 10 vs. 74.7 ± 14 cm 2 , P < 0.001), 29% lower fascicle force (702 ± 235 vs. 1704 ± 303 N, P < 0.001), and 29% lower specific force than control subjects (17 ± 6 vs. 24 ± 6 N⋅cm -2 , P = 0.012). The smaller VL specific force in achondroplasia may be attributed to infiltration of fat and connective tissue, rather than to any difference in myofilament function. NEW & NOTEWORTHY The novel observation of this study was the measurement of normalized force production in a group of individuals with disproportionate limb length-to-torso ratios.

Three forms of immune myasthenia.

PubMed

Agius, Mark A; Richman, David P; Fairclough, Robert H; Aarli, Johan; Gilhus, Nils Erik; Romi, Fredrik

2003-09-01

We propose a new classification for immune myasthenia based on antibody pattern. The types of immune myasthenia presently characterized by known antibody targets segregate into three groups: type 1, in which the muscle target is the acetylcholine receptor only; type 2, in which titin antibodies are present in addition to acetylcholine receptor antibodies; and type 3, in which muscle-specific kinase antibodies are present in the absence of acetylcholine receptor antibodies. The immune target is unknown in the patients with immune myasthenia not associated with these antibodies. This classification has advantages over the present classifications as regards homogeneity of groups, etiology, mechanism of disease, and prognosis.

Electrophysiological Correlates of the Threshold to Detection of Passive Motion: An Investigation in Professional Volleyball Athletes with and without Atrophy of the Infraspinatus Muscle

PubMed Central

Salles, José Inácio; Cossich, Victor Rodrigues Amaral; Amaral, Marcus Vinicius; Monteiro, Martim T.; Cagy, Maurício; Motta, Geraldo; Velasques, Bruna; Piedade, Roberto; Ribeiro, Pedro

2013-01-01

The goal of the present study is to compare the electrophysiological correlates of the threshold to detection of passive motion (TTDPM) among three groups: healthy individuals (control group), professional volleyball athletes with atrophy of the infraspinatus muscle on the dominant side, and athletes with no shoulder pathologies. More specifically, the study aims at assessing the effects of infraspinatus muscle atrophy on the cortical representation of the TTDPM. A proprioception testing device (PTD) was used to measure the TTDPM. The device passively moved the shoulder and participants were instructed to respond as soon as movement was detected (TTDPM) by pressing a button switch. Response latency was established as the delay between the stimulus (movement) and the response (button press). Electroencephalographic (EEG) and electromyographic (EMG) activities were recorded simultaneously. An analysis of variance (ANOVA) and subsequent post hoc tests indicated a significant difference in latency between the group of athletes without the atrophy when compared both to the group of athletes with the atrophy and to the control group. Furthermore, distinct patterns of cortical activity were observed in the three experimental groups. The results suggest that systematically trained motor abilities, as well as the atrophy of the infraspinatus muscle, change the cortical representation of the different stages of proprioceptive information processing and, ultimately, the cortical representation of the TTDPM. PMID:23484136

Fast-digestive protein supplement for ten days overcomes muscle anabolic resistance in healthy elderly men.

PubMed

Walrand, Stéphane; Gryson, Céline; Salles, Jérôme; Giraudet, Christophe; Migné, Carole; Bonhomme, Cécile; Le Ruyet, Pascale; Boirie, Yves

2016-06-01

Adequate protein intake is crucial to maintain muscle protein content in elderly subjects, but quality of dietary proteins should be considered. The aim was to determine whether soluble milk protein offers an original strategy to increase muscle anabolism in elderly subjects via a synergistic effect of fast-digesting proteins together with a unique essential AA content. We investigated the effect of a 10-day adequate-protein (AP) or high-protein (HP) diet together with the protein source as caseins (CAS) or soluble milk proteins (PRO) on specific muscle protein fractional synthesis rates (FSRs) in healthy elderly men (71.8 ± 2.4 yr, n = 31). The isotopic study consisted of two periods of 4 h each: a post-absorptive and a postprandial period. The fed state was defined by consumption of either 15 g or 30 g of PRO or CAS, given fractionally every 20 min for 4 h. Soluble milk proteins are produced using a membrane process directly from pasteurized milk. Specific muscle protein FSRs were measured during both postabsorptive and postprandial period using a continuous infusion of l-[1-(13)C]leucine. FSR of sarcoplasmic muscle proteins and actin did not increase significantly in the postprandial state compared to postabsorptive state, whereas myosin FSR rate was increased by feeding whatever the protein source in HP groups (0.024 ± 0.005 vs 0.053 ± 0.011% h(-1), P < 0.05 and 0.026 ± 0.004 vs 0.050 ± 0.005% h(-1), P < 0.004 for PRO HP and CAS HP) but only with the PRO meal in the AP groups (0.031 ± 0.003 vs 0.062 ± 0.009% h(-1), P < 0.03 for PRO AP). Mitochondrial muscle protein FSR was also increased by feeding, irrespective of the protein quantity, but only in PRO meal groups (P < 0.02). Fast-digesting soluble milk proteins improved postprandial muscle protein synthesis, especially mitochondrial muscle proteins and myosin fractional synthesis rates, in elderly subjects. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Non-elite gymnastics participation is associated with greater bone strength, muscle size, and function in pre- and early pubertal girls.

PubMed

Burt, L A; Naughton, G A; Greene, D A; Courteix, D; Ducher, G

2012-04-01

Recent reports indicate an increase in forearm fractures in children. Bone geometric properties are an important determinant of bone strength and therefore fracture risk. Participation in non-elite gymnastics appears to contribute to improving young girls' musculoskeletal health, more specifically in the upper body. The primary aim of this study was to determine the association between non-elite gymnastics participation and upper limb bone mass, geometry, and strength in addition to muscle size and function in young girls. Eighty-eight pre- and early pubertal girls (30 high-training gymnasts [HGYM, 6-16 hr/ wk], 29 low-training gymnasts [LGYM, 1-5 h r/wk] and 29 non-gymnasts [NONGYM]), aged 6-11 years were recruited. Upper limb lean mass, BMD and BMC were derived from a whole body DXA scan. Forearm volumetric BMD, bone geometry, estimated strength, and muscle CSA were determined using peripheral QCT. Upper body muscle function was investigated with muscle strength, explosive power, and muscle endurance tasks. HGYM showed greater forearm bone strength compared with NGYM, as well as greater arm lean mass, BMC, and muscle function (+5% to +103%, p < 0.05). LGYM displayed greater arm lean mass, BMC, muscle power, and endurance than NGYM (+4% to +46%, p < 0.05); however, the difference in bone strength did not reach significance. Estimated fracture risk at the distal radius, which accounted for body weight, was lower in both groups of gymnasts. Compared with NONGYM, HGYM tended to show larger skeletal differences than LGYM; yet, the two groups of gymnasts only differed for arm lean mass and muscle CSA. Non-elite gymnastics participation was associated with musculoskeletal benefits in upper limb bone geometry, strength and muscle function. Differences between the two gymnastic groups emerged for arm lean mass and muscle CSA, but not for bone strength.

Prediction of isometric motor tasks and effort levels based on high-density EMG in patients with incomplete spinal cord injury

NASA Astrophysics Data System (ADS)

Jordanić, Mislav; Rojas-Martínez, Mónica; Mañanas, Miguel Angel; Francesc Alonso, Joan

2016-08-01

Objective. The development of modern assistive and rehabilitation devices requires reliable and easy-to-use methods to extract neural information for control of devices. Group-specific pattern recognition identifiers are influenced by inter-subject variability. Based on high-density EMG (HD-EMG) maps, our research group has already shown that inter-subject muscle activation patterns exist in a population of healthy subjects. The aim of this paper is to analyze muscle activation patterns associated with four tasks (flexion/extension of the elbow, and supination/pronation of the forearm) at three different effort levels in a group of patients with incomplete Spinal Cord Injury (iSCI). Approach. Muscle activation patterns were evaluated by the automatic identification of these four isometric tasks along with the identification of levels of voluntary contractions. Two types of classifiers were considered in the identification: linear discriminant analysis and support vector machine. Main results. Results show that performance of classification increases when combining features extracted from intensity and spatial information of HD-EMG maps (accuracy = 97.5%). Moreover, when compared to a population with injuries at different levels, a lower variability between activation maps was obtained within a group of patients with similar injury suggesting stronger task-specific and effort-level-specific co-activation patterns, which enable better prediction results. Significance. Despite the challenge of identifying both the four tasks and the three effort levels in patients with iSCI, promising results were obtained which support the use of HD-EMG features for providing useful information regarding motion and force intention.

The value of multiple tests of respiratory muscle strength

PubMed Central

Steier, Joerg; Kaul, Sunny; Seymour, John; Jolley, Caroline; Rafferty, Gerrard; Man, William; Luo, Yuan M; Roughton, Michael; Polkey, Michael I; Moxham, John

2007-01-01

Background Respiratory muscle weakness is an important clinical problem. Tests of varying complexity and invasiveness are available to assess respiratory muscle strength. The relative precision of different tests in the detection of weakness is less clear, as is the value of multiple tests. Methods The respiratory muscle function tests of clinical referrals who had multiple tests assessed in our laboratories over a 6‐year period were analysed. Thresholds for weakness for each test were determined from published and in‐house laboratory data. The patients were divided into three groups: those who had all relevant measurements of global inspiratory muscle strength (group A, n = 182), those with full assessment of diaphragm strength (group B, n = 264) and those for whom expiratory muscle strength was fully evaluated (group C, n = 60). The diagnostic outcome of each inspiratory, diaphragm and expiratory muscle test, both singly and in combination, was studied and the impact of using more than one test to detect weakness was calculated. Results The clinical referrals were primarily for the evaluation of neuromuscular diseases and dyspnoea of unknown cause. A low maximal inspiratory mouth pressure (Pimax) was recorded in 40.1% of referrals in group A, while a low sniff nasal pressure (Sniff Pnasal) was recorded in 41.8% and a low sniff oesophageal pressure (Sniff Poes) in 37.9%. When assessing inspiratory strength with the combination of all three tests, 29.6% of patients had weakness. Using the two non‐invasive tests (Pimax and Sniff Pnasal) in combination, a similar result was obtained (low in 32.4%). Combining Sniff Pdi (low in 68.2%) and Twitch Pdi (low in 67.4%) reduced the diagnoses of patients with diaphragm weakness to 55.3% in group B. 38.3% of the patients in group C had expiratory muscle weakness as measured by maximum expiratory pressure (Pemax) compared with 36.7% when weakness was diagnosed by cough gastric pressure (Pgas), and 28.3% when assessed by Twitch T10. Combining all three expiratory muscle tests reduced the number of patients diagnosed as having expiratory muscle weakness to 16.7%. Conclusion The use of single tests such as Pimax, Pemax and other available individual tests of inspiratory, diaphragm and expiratory muscle strength tends to overdiagnose weakness. Combinations of tests increase diagnostic precision and, in the population studied, they reduced the diagnosis of inspiratory, specific diaphragm and expiratory muscle weakness by 19–56%. Measuring both Pimax and Sniff Pnasal resulted in a relative reduction of 19.2% of patients falsely diagnosed with inspiratory muscle weakness. The addition of Twitch Pdi to Sniff Pdi increased diagnostic precision by a smaller amount (18.9%). Having multiple tests of respiratory muscle function available both increases diagnostic precision and makes assessment possible in a range of clinical circumstances. PMID:17557772

A training paradigm to enhance motor recovery in contused rats: effects of staircase training.

PubMed

Singh, Anita; Murray, Marion; Houle, John D

2011-01-01

Ambulating on stairs is an important aspect of daily activities for many individuals with incomplete spinal cord injury (SCI), and little is known about the effect of training for this specific task. The goal of this study was to determine whether staircase ascent training enhances motor recovery in animals with contusion injury. Rats received a midthoracic contusion lesion of moderate severity and were randomly divided into 2 groups, with one group receiving staircase ascent training for up to 8 weeks and the other receiving no training. To assess the direct effect of training, a task-specific staircase climbing test was performed. Open field test (BBB) and gait analysis (CatWalk) assessed overground recovery, and a grid test was used to assess improvement in sensorimotor tasks. Changes in muscle mass of the forelimb and hindlimb muscles were also measured, and the extent of spared white matter was determined for lesion verification and anatomical correlations. Staircase training improved the task-specific performance of ascent. Gait parameters, including base of support, stride length, regularity index (RI), and step sequence, also improved. Overground locomotion and the grid test, both showed a trend of improved performance. Finally, hindlimb muscle mass was maintained with training. Staircase ascent training after incomplete SCI has beneficial effects on task-specific as well as nonspecific motor and sensorimotor activities.

Biological organization of the extraocular muscles.

PubMed

Spencer, Robert F; Porter, John D

2006-01-01

Extraocular muscle is fundamentally distinct from other skeletal muscles. Here, we review the biological organization of the extraocular muscles with the intent of understanding this novel muscle group in the context of oculomotor system function. The specific objectives of this review are threefold. The first objective is to understand the anatomic arrangement of the extraocular muscles and their compartmental or layered organization in the context of a new concept of orbital mechanics, the active pulley hypothesis. The second objective is to present an integrated view of the morphologic, cellular, and molecular differences between extraocular and the more traditional skeletal muscles. The third objective is to relate recent data from functional and molecular biology studies to the established extraocular muscle fiber types. Developmental mechanisms that may be responsible for the divergence of the eye muscles from a skeletal muscle prototype also are considered. Taken together, a multidisciplinary understanding of extraocular muscle biology in health and disease provides insights into oculomotor system function and malfunction. Moreover, because the eye muscles are selectively involved or spared in a variety of neuromuscular diseases, knowledge of their biology may improve current pathogenic models of and treatments for devastating systemic diseases.

Motor Unit Changes Seen With Skeletal Muscle Sarcopenia in Oldest Old Rats

PubMed Central

Kung, Theodore A.; van der Meulen, Jack H.; Urbanchek, Melanie G.; Kuzon, William M.; Faulkner, John A.

2014-01-01

Sarcopenia leads to many changes in skeletal muscle that contribute to atrophy, force deficits, and subsequent frailty. The purpose of this study was to characterize motor unit remodeling related to sarcopenia seen in extreme old age. Whole extensor digitorum longus muscle and motor unit contractile properties were measured in 19 adult (11–13 months) and 12 oldest old (36–37 months) Brown-Norway rats. Compared with adults, oldest old rats had significantly fewer motor units per muscle, smaller muscle cross-sectional area, and lower muscle specific force. However, mean motor unit force generation was similar between the two groups due to an increase in innervation ratio by the oldest old rats. These findings suggest that even in extreme old age both fast- and slow-twitch motor units maintain the ability to undergo motor unit remodeling that offsets some effects of sarcopenia. PMID:24077596

Effects of Electrical Stimulation on Skeletal Muscle of Old Sedentary People

PubMed Central

Mosole, Simone; Zampieri, Sandra; Furlan, Sandra; Carraro, Ugo; Löefler, Stefan; Kern, Helmut; Volpe, Pompeo

2018-01-01

Physical activity plays an important role in preventing muscle atrophy and chronic diseases in adults and in the elderly. Calcium (Ca2+) cycling and activation of specific molecular pathways are essential in contraction-induced muscle adaptation. This study attains human muscle sections and total homogenates prepared from biopsies obtained before (control) and after 9 weeks of training by electrical stimulation (ES) on a group of volunteers. The aim of the study was to investigate about the molecular mechanisms that support functional muscle improvement by ES. Evidences of kinase/phosphatase pathways activation after ES were obtained. Moreover, expression of Sarcalumenin, Calsequestrin and sarco/endoplasmic reticulum Ca2+-ATPase (Serca) isoforms was regulated by training. In conclusion, this work shows that neuromuscular ES applied to vastus lateralis muscle of sedentary seniors combines fiber remodeling with activation of Ca2+-Calmodulin molecular pathways and modulation of key Ca2+-handling proteins. PMID:29662923

Effect of acid swallowing on esophageal contraction in patients with heartburn related to hypersensitivity.

PubMed

Lee, Hyuk; Lee, Sang Kil; Park, Jun Chul; Shin, Sung Kwan; Lee, Yong Chan

2013-01-01

There are heterogeneous subgroups among those with heartburn, and data on these individuals are relatively scant. We aimed to evaluate the effect of acid challenge on the segmental contractions of esophageal smooth muscle in endoscopy-negative patients with normal esophageal acid exposure. High-resolution esophageal manometry (HRM) was performed on 30 endoscopy-negative patients with heartburn accompanied by normal esophageal acid exposure using 10 water swallows followed by 10 acidic pomegranate juice swallows. Patients were classified into functional heartburn (FH) and hypersensitive esophagus (HE) groups based on the results of 24-hr impedance pH testing. HRM topographic plots were analyzed and maximal wave amplitude and pressure volumes were measured for proximal and distal smooth muscle segments. The pressure volume of the distal smooth muscle segment in the HE group measured during acidic swallows was higher than during water swallows (2224.1 ± 68.2 mmHg/cm per s versus 2105.6 ± 66.4 mmHg/cm per s, P = 0.027). A prominent shift in the pressure volume to the distal smooth muscle segment was observed in the HE group compared with the FH group (segmental ratio: 2.72 ± 0.08 versus 2.39 ± 0.07, P = 0.005). Manometric measurements during acidic swallows revealed that this shift was augmented in the HE group. The optimal ratio of pomegranate juice swallowing for discrimination of FH from HE was 2.82, with a sensitivity of 88.9% and a specificity of 100%. Hypercontractile response of distal smooth muscle segment to acid swallowing was more prominent in the HE group than the FH group. © 2012 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

Clinical significance of serum and urinary HER2/neu protein levels in primary non-muscle invasive bladder cancer.

PubMed

Arikan, Ozgur; Yýldýrým, Asýf; Ýsbilen, Banu; Canakci, Cengiz; Atýs, Gokhan; Gurbuz, Cenk; Erol, Bulent; Ýsman, Ferruh Kemal; Ozkanli, Seyma; Caskurlu, Turhan

2015-01-01

We aimed to compare serum and urinary HER2/neu levels between healthy control group and patients with non-muscle invasive bladder cancer. Additionally, we evaluated relationship of HER2/neu levels with tumor stage, grade, recurrence and progression. Fourty-four patients with primary non-muscle invasive bladder tumors (Group 2) and 40 healthy control group (Group 1) were included the study. Blood and urinary samples were collected from all patients and HER2/neu levels were measured by ELISA method. Blood and urinary HER2/neu levels and additionally, ratio of urinary HER2/neu levels to urinary creatinine levels were recorded. Demographic data and tumor characteristics were recorded. Mean serum HER2/neu levels were similar between two groups and statistically significant difference wasn't observed. Urinary HER2/neu levels were significantly higher in group 2 than group 1. Ratio of urinary HER2/neu to urinary creatinine was significantly higher in group 2 than group 1, (p=0,021). Serum and urinary HER2/ neu levels were not associated with tumor stage, grade, recurrence and progression while ratio of urinary HER2/neu to urinary creatinin levels were significantly higher in high-grade tumors. HER2/neu, the sensitivity of the test was found to be 20.5%, and the specificity was 97.5%, also for the urinary HER2/neu/urinary creatinine ratio, the sensitivity and specificity of the test were found to be 31.8% and 87.5%, respectively. Urinary HER2/neu and ratio of urinary creatinine urine were significantly higher in patients with bladder cancer compared to healthy subjects. Large series and controlled studies are needed for use as a tumor marker.

Neuromusculoskeletal models based on the muscle synergy hypothesis for the investigation of adaptive motor control in locomotion via sensory-motor coordination.

PubMed

Aoi, Shinya; Funato, Tetsuro

2016-03-01

Humans and animals walk adaptively in diverse situations by skillfully manipulating their complicated and redundant musculoskeletal systems. From an analysis of measured electromyographic (EMG) data, it appears that despite complicated spatiotemporal properties, muscle activation patterns can be explained by a low dimensional spatiotemporal structure. More specifically, they can be accounted for by the combination of a small number of basic activation patterns. The basic patterns and distribution weights indicate temporal and spatial structures, respectively, and the weights show the muscle sets that are activated synchronously. In addition, various locomotor behaviors have similar low dimensional structures and major differences appear in the basic patterns. These analysis results suggest that neural systems use muscle group combinations to solve motor control redundancy problems (muscle synergy hypothesis) and manipulate those basic patterns to create various locomotor functions. However, it remains unclear how the neural system controls such muscle groups and basic patterns through neuromechanical interactions in order to achieve adaptive locomotor behavior. This paper reviews simulation studies that explored adaptive motor control in locomotion via sensory-motor coordination using neuromusculoskeletal models based on the muscle synergy hypothesis. Herein, the neural mechanism in motor control related to the muscle synergy for adaptive locomotion and a potential muscle synergy analysis method including neuromusculoskeletal modeling for motor impairments and rehabilitation are discussed. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Epigallocatechin-3-gallate improves plantaris muscle recovery after disuse in aged rats

PubMed Central

Alway, Stephen E.; Bennett, Brian T.; Wilson, Joseph C.; Edens, Neile K.; Pereira, Suzette L.

2014-01-01

Aging exacerbates muscle loss and slows the recovery of muscle mass and function after disuse. In this study we investigated the potential that epigallocatechin gallate (EGCg), an abundant catechin in green tea, would reduce signaling for apoptosis and promote skeletal muscle recovery in the fast plantaris muscle and the slow soleus muscle after hindlimb unloading (HLS) in senescent animals. Fischer 344 × Brown Norway inbred rats (age 34 mo.) received either EGCg (50 mg/kg body weight), or water daily by gavage. One group of animals received HLS for 14 days and a second group of rats received 14 days of HLS, then the HLS was removed and they recovered from this forced disuse for 2 weeks. Animals that received EGCg over the HLS followed by 14 days of recovery, had a 14% greater plantaris muscle weight (p <0.05) as compared to the animals treated with the vehicle over this same period. Plantaris fiber area was greater after recovery in EGCg (2715.2 ± 113.8 μm2) vs. vehicle treated animals (1953.0 ± 41.9 μm2). In addition, activation of myogenic progenitor cells was improved with EGCg over vehicle treatment (7.5% vs. 6.2%) in the recovery animals. Compared to vehicle treatment, the apoptotic index was lower (0.24% vs. 0.52%), and the abundance of pro-apoptotic proteins Bax (−22%), and FADD (−77%) were lower in EGCg treated plantaris muscles after recovery. While EGCg did not prevent unloading-induced atrophy, it improved muscle recovery after the atrophic stimulus in fast plantaris muscles. However, this effect was muscle specific because EGCg had no major impact in reversing HLS-induced atrophy in the slow soleus muscle of old rats. PMID:24316035

Skeletal muscle phosphatidylcholine and phosphatidylethanolamine are related to insulin sensitivity and respond to acute exercise in humans.

PubMed

Newsom, Sean A; Brozinick, Joseph T; Kiseljak-Vassiliades, Katja; Strauss, Allison N; Bacon, Samantha D; Kerege, Anna A; Bui, Hai Hoang; Sanders, Phil; Siddall, Parker; Wei, Tao; Thomas, Melissa; Kuo, Ming Shang; Nemkov, Travis; D'Alessandro, Angelo; Hansen, Kirk C; Perreault, Leigh; Bergman, Bryan C

2016-06-01

Several recent reports indicate that the balance of skeletal muscle phosphatidylcholine (PC) and phosphatidylethanolamine (PE) is a key determinant of muscle contractile function and metabolism. The purpose of this study was to determine relationships between skeletal muscle PC, PE and insulin sensitivity, and whether PC and PE are dynamically regulated in response to acute exercise in humans. Insulin sensitivity was measured via intravenous glucose tolerance in sedentary obese adults (OB; n = 14), individuals with type 2 diabetes (T2D; n = 15), and endurance-trained athletes (ATH; n = 15). Vastus lateralis muscle biopsies were obtained at rest, immediately after 90 min of cycle ergometry at 50% maximal oxygen consumption (V̇o2 max), and 2-h postexercise (recovery). Skeletal muscle PC and PE were measured via infusion-based mass spectrometry/mass spectrometry analysis. ATH had greater levels of muscle PC and PE compared with OB and T2D (P < 0.05), with total PC and PE positively relating to insulin sensitivity (both P < 0.05). Skeletal muscle PC:PE ratio was elevated in T2D compared with OB and ATH (P < 0.05), tended to be elevated in OB vs. ATH (P = 0.07), and was inversely related to insulin sensitivity among the entire cohort (r = -0.43, P = 0.01). Muscle PC and PE were altered by exercise, particularly after 2 h of recovery, in a highly group-specific manner. However, muscle PC:PE ratio remained unchanged in all groups. In summary, total muscle PC and PE are positively related to insulin sensitivity while PC:PE ratio is inversely related to insulin sensitivity in humans. A single session of exercise significantly alters skeletal muscle PC and PE levels, but not PC:PE ratio. Copyright © 2016 the American Physiological Society.

Skeletal muscle phosphatidylcholine and phosphatidylethanolamine are related to insulin sensitivity and respond to acute exercise in humans

PubMed Central

Newsom, Sean A.; Brozinick, Joseph T.; Kiseljak-Vassiliades, Katja; Strauss, Allison N.; Bacon, Samantha D.; Kerege, Anna A.; Bui, Hai Hoang; Sanders, Phil; Siddall, Parker; Wei, Tao; Thomas, Melissa; Kuo, Ming Shang; Nemkov, Travis; D'Alessandro, Angelo; Hansen, Kirk C.; Perreault, Leigh

2016-01-01

Several recent reports indicate that the balance of skeletal muscle phosphatidylcholine (PC) and phosphatidylethanolamine (PE) is a key determinant of muscle contractile function and metabolism. The purpose of this study was to determine relationships between skeletal muscle PC, PE and insulin sensitivity, and whether PC and PE are dynamically regulated in response to acute exercise in humans. Insulin sensitivity was measured via intravenous glucose tolerance in sedentary obese adults (OB; n = 14), individuals with type 2 diabetes (T2D; n = 15), and endurance-trained athletes (ATH; n = 15). Vastus lateralis muscle biopsies were obtained at rest, immediately after 90 min of cycle ergometry at 50% maximal oxygen consumption (V̇o2 max), and 2-h postexercise (recovery). Skeletal muscle PC and PE were measured via infusion-based mass spectrometry/mass spectrometry analysis. ATH had greater levels of muscle PC and PE compared with OB and T2D (P < 0.05), with total PC and PE positively relating to insulin sensitivity (both P < 0.05). Skeletal muscle PC:PE ratio was elevated in T2D compared with OB and ATH (P < 0.05), tended to be elevated in OB vs. ATH (P = 0.07), and was inversely related to insulin sensitivity among the entire cohort (r = −0.43, P = 0.01). Muscle PC and PE were altered by exercise, particularly after 2 h of recovery, in a highly group-specific manner. However, muscle PC:PE ratio remained unchanged in all groups. In summary, total muscle PC and PE are positively related to insulin sensitivity while PC:PE ratio is inversely related to insulin sensitivity in humans. A single session of exercise significantly alters skeletal muscle PC and PE levels, but not PC:PE ratio. PMID:27032901

Epigallocatechin-3-gallate improves plantaris muscle recovery after disuse in aged rats.

PubMed

Alway, Stephen E; Bennett, Brian T; Wilson, Joseph C; Edens, Neile K; Pereira, Suzette L

2014-02-01

Aging exacerbates muscle loss and slows the recovery of muscle mass and function after disuse. In this study we investigated the potential that epigallocatechin-3-gallate (EGCg), an abundant catechin in green tea, would reduce signaling for apoptosis and promote skeletal muscle recovery in the fast plantaris muscle and the slow soleus muscle after hindlimb suspension (HLS) in senescent animals. Fischer 344 × Brown Norway inbred rats (age 34 months) received either EGCg (50 mg/kg body weight), or water daily by gavage. One group of animals received HLS for 14 days and a second group of rats received 14 days of HLS, then the HLS was removed and they recovered from this forced disuse for 2 weeks. Animals that received EGCg over the HLS followed by 14 days of recovery, had a 14% greater plantaris muscle weight (p<0.05) as compared to the animals treated with the vehicle over this same period. Plantaris fiber area was greater after recovery in EGCg (2715.2±113.8 μm(2)) vs. vehicle treated animals (1953.0±41.9 μm(2)). In addition, activation of myogenic progenitor cells was improved with EGCg over vehicle treatment (7.5% vs. 6.2%) in the recovery animals. Compared to vehicle treatment, the apoptotic index was lower (0.24% vs. 0.52%), and the abundance of pro-apoptotic proteins Bax (-22%), and FADD (-77%) was lower in EGCg treated plantaris muscles after recovery. While EGCg did not prevent unloading-induced atrophy, it improved muscle recovery after the atrophic stimulus in fast plantaris muscles. However, this effect was muscle specific because EGCg had no major impact in reversing HLS-induced atrophy in the slow soleus muscle of old rats. Copyright © 2013 Elsevier Inc. All rights reserved.

Scapular-Muscle Performance: Two Training Programs in Adolescent Swimmers

PubMed Central

Van de Velde, Annemie; De Mey, Kristof; Maenhout, Annelies; Calders, Patrick; Cools, Ann M.

2011-01-01

Abstract Context: Swimming requires well-balanced scapular-muscle performance. An additional strength-training program for the shoulders is pursued by swimmers, but whether these muscle-training programs need to be generic or specific for endurance or strength is unknown. Objective: To evaluate isokinetic scapular-muscle performance in a population of adolescent swimmers and to compare the results of training programs designed for strength or muscle endurance. Design: Controlled laboratory study. Setting: University human research laboratory. Patients or Other Participants: Eighteen adolescent swimmers. Intervention(s): Each participant pursued a 12-week scapular-training program designed to improve either muscle strength or muscle endurance. Main Outcome Measure(s): Bilateral peak force, fatigue index, and protraction/retraction strength ratios before and after the scapular-training program. Results: Scapular protraction/retraction ratios were slightly higher than 1 (dominant side  =  1.08, nondominant side  =  1.25, P  =  .006). Side-to-side differences in retraction strength were apparent both before and after the training program (P  =  .03 and P  = .05, respectively). After the training program, maximal protraction (P < .05) and retraction (P < .01) strength improved on the nondominant side. Peak force and fatigue index were not different between the training groups. The fatigue indexes for protraction on both sides (P < .05) and retraction on the nondominant side (P  =  .009) were higher after the training program. Conclusions: We describe the scapular-muscle characteristics of a group of adolescent swimmers. Both muscle-strength and muscle-endurance programs improved absolute muscle strength. Neither of the strength programs had a positive effect on scapular-muscle endurance. Our results may be valuable for coaches and physiotherapists when they are designing exercise programs for swimmers. PMID:21391801

Metabolic Diseases of Muscle

MedlinePlus

... diets. Your MDA clinic director can help you design a specific plan suited for your metabolic disorder ... respira- tory or speech therapy consultations • annual flu shots • support groups for those affected, spouses, parents or ...

Patients with ALS show highly correlated progression rates in left and right limb muscles.

PubMed

Rushton, David J; Andres, Patricia L; Allred, Peggy; Baloh, Robert H; Svendsen, Clive N

2017-07-11

Amyotrophic lateral sclerosis (ALS) progresses at different rates between patients, making clinical trial design difficult and dependent on large cohorts of patients. Currently, there are few data showing whether the left and right limbs progress at the same or different rates. This study addresses rates of decline in specific muscle groups of patients with ALS and assesses whether there is a relationship between left and right muscles in the same patient, regardless of overall progression. A large cohort of patients was used to assess decline in muscle strength in right and left limbs over time using 2 different methods: The Tufts Quantitative Neuromuscular Exam and Accurate Test of Limb Isometric Strength protocol. Then advanced linear regression statistical methods were applied to assess progression rates in each limb. This report shows that linearized progression models can predict general slopes of decline with good accuracy. Critically, the data demonstrate that while overall decline is variable, there is a high degree of correlation between left and right muscle decline in ALS. This implies that irrespective of which muscle starts declining soonest or latest, their rates of decline following onset are more consistent. First, this study demonstrates a high degree of power when using unilateral treatment approaches to detect a slowing in disease progression in smaller groups of patients, thus allowing for paired statistical tests. These findings will be useful in transplantation trials that use muscle decline to track disease progression in ALS. Second, these findings discuss methods, such as tactical selection of muscle groups, which can improve the power efficiency of all ALS clinical trials. Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

Contribution of inter-muscular synchronization in the modulation of tremor intensity in Parkinson's disease.

PubMed

He, Xin; Hao, Man-Zhao; Wei, Ming; Xiao, Qin; Lan, Ning

2015-12-01

Involuntary central oscillations at single and double tremor frequencies drive the peripheral neuromechanical system of muscles and joints to cause tremor in Parkinson's disease (PD). The central signal of double tremor frequency was found to correlate more directly to individual muscle EMGs (Timmermann et al. 2003). This study is aimed at investigating what central components of oscillation contribute to inter-muscular synchronization in a group of upper extremity muscles during tremor in PD patients. 11 idiopathic, tremor dominant PD subjects participated in this study. Joint kinematics during tremor in the upper extremity was recorded along with EMGs of six upper arm muscles using a novel experimental apparatus. The apparatus provided support for the upper extremity on a horizontal surface with reduced friction, so that resting tremor in the arm can be recorded with a MotionMonitor II system. In each subject, the frequencies of rhythmic firings in upper arm muscles were determined using spectral analysis. Paired and pool-averaged coherence analyses of EMGs for the group of muscles were performed to correlate the level of inter-muscular synchronization to tremor amplitudes at shoulder and elbow. The phase shift between synchronized antagonistic muscle pairs was calculated to aid coherence analysis in the muscle pool. Recorded EMG revealed that rhythmic firings were present in most recorded muscles, which were either synchronized to form phase-locked bursting cycles at a subject specific frequency, or unsynchronized with a random phase distribution. Paired coherence showed a stronger synchronization among a subset of recorded arm muscles at tremor frequency than that at double tremor frequency. Furthermore, the number of synchronized muscles in the arm was positively correlated to tremor amplitudes at elbow and shoulder. Pool-averaged coherence at tremor frequency also showed a better correlation with the amplitude of resting tremor than that of double tremor frequency, indicating that the neuromechanical coupling in peripheral neuromuscular system was stronger at tremor frequency. Both paired and pool-averaged coherences are more consistent indexes to correlate to tremor intensity in a group of upper extremity muscles of PD patients. The central drive at tremor frequency contributes mainly to synchronize peripheral muscles in the modulation of tremor intensity.

Assessment of breathing patterns and respiratory muscle recruitment during singing and speech in quadriplegia.

PubMed

Tamplin, Jeanette; Brazzale, Danny J; Pretto, Jeffrey J; Ruehland, Warren R; Buttifant, Mary; Brown, Douglas J; Berlowitz, David J

2011-02-01

To explore how respiratory impairment after cervical spinal cord injury affects vocal function, and to explore muscle recruitment strategies used during vocal tasks after quadriplegia. It was hypothesized that to achieve the increased respiratory support required for singing and loud speech, people with quadriplegia use different patterns of muscle recruitment and control strategies compared with control subjects without spinal cord injury. Matched, parallel-group design. Large university-affiliated public hospital. Consenting participants with motor-complete C5-7 quadriplegia (n=6) and able-bodied age-matched controls (n=6) were assessed on physiologic and voice measures during vocal tasks. Not applicable. Standard respiratory function testing, surface electromyographic activity from accessory respiratory muscles, sound pressure levels during vocal tasks, the Voice Handicap Index, and the Perceptual Voice Profile. The group with quadriplegia had a reduced lung capacity (vital capacity, 71% vs 102% of predicted; P=.028), more perceived voice problems (Voice Handicap Index score, 22.5 vs 6.5; P=.046), and greater recruitment of accessory respiratory muscles during both loud and soft volumes (P=.028) than the able-bodied controls. The group with quadriplegia also demonstrated higher accessory muscle activation in changing from soft to loud speech (P=.028). People with quadriplegia have impaired vocal ability and use different muscle recruitment strategies during speech than the able-bodied. These findings will enable us to target specific measurements of respiratory physiology for assessing functional improvements in response to formal therapeutic singing training. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Comparison of training methods to improve walking in persons with chronic spinal cord injury: a randomized clinical trial

PubMed Central

Alexeeva, Natalia; Sames, Carol; Jacobs, Patrick L.; Hobday, Lori; DiStasio, Marcello M.; Mitchell, Sarah A.; Calancie, Blair

2011-01-01

Objective To compare two forms of device-specific training – body-weight-supported (BWS) ambulation on a fixed track (TRK) and BWS ambulation on a treadmill (TM) – to comprehensive physical therapy (PT) for improving walking speed in persons with chronic, motor-incomplete spinal cord injury (SCI). Methods Thirty-five adult subjects with a history of chronic SCI (>1 year; AIS ‘C’ or ‘D’) participated in a 13-week (1 hour/day; 3 days per week) training program. Subjects were randomized into one of the three training groups. Subjects in the two BWS groups trained without the benefit of additional input from a physical therapist or gait expert. For each training session, performance values and heart rate were monitored. Pre- and post-training maximal 10-m walking speed, balance, muscle strength, fitness, and quality of life were assessed in each subject. Results All three training groups showed significant improvement in maximal walking speed, muscle strength, and psychological well-being. A significant improvement in balance was seen for PT and TRK groups but not for subjects in the TM group. In all groups, post-training measures of fitness, functional independence, and perceived health and vitality were unchanged. Conclusions Our results demonstrate that persons with chronic, motor-incomplete SCI can improve walking ability and psychological well-being following a concentrated period of ambulation therapy, regardless of training method. Improvement in walking speed was associated with improved balance and muscle strength. In spite of the fact that we withheld any formal input of a physical therapist or gait expert from subjects in the device-specific training groups, these subjects did just as well as subjects receiving comprehensive PT for improving walking speed and strength. It is likely that further modest benefits would accrue to those subjects receiving a combination of device-specific training with input from a physical therapist or gait expert to guide that training. PMID:21903010

Benefits of skeletal-muscle exercise training in pulmonary arterial hypertension: The WHOLEi+12 trial.

PubMed

González-Saiz, Laura; Fiuza-Luces, Carmen; Sanchis-Gomar, Fabian; Santos-Lozano, Alejandro; Quezada-Loaiza, Carlos A; Flox-Camacho, Angela; Munguía-Izquierdo, Diego; Ara, Ignacio; Santalla, Alfredo; Morán, María; Sanz-Ayan, Paz; Escribano-Subías, Pilar; Lucia, Alejandro

2017-03-15

Pulmonary arterial hypertension is often associated with skeletal-muscle weakness. The purpose of this randomized controlled trial was to determine the effects of an 8-week intervention combining muscle resistance, aerobic and inspiratory pressure-load exercises on upper/lower-body muscle power and other functional variables in patients with this disease. Participants were allocated to a control (standard care) or intervention (exercise) group (n=20 each, 45±12 and 46±11years, 60% women and 10% patients with chronic thromboembolic pulmonary hypertension per group). The intervention included five, three and six supervised (inhospital) sessions/week of aerobic, resistance and inspiratory muscle training, respectively. The primary endpoint was peak muscle power during bench/leg press; secondary outcomes included N-terminal pro-brain natriuretic peptide levels, 6-min walking distance, five-repetition sit-to-stand test, maximal inspiratory pressure, cardiopulmonary exercise testing variables (e.g., peak oxygen uptake), health-related quality of life, physical activity levels, and safety. Adherence to training sessions averaged 94±0.5% (aerobic), 98±0.3% (resistance) and 91±1% (inspiratory training). Analysis of variance showed a significant interaction (group×time) effect for leg/bench press (P<0.001/P=0.002), with both tests showing an improvement in the exercise group (P<0.001) but not in controls (P>0.1). We found a significant interaction effect (P<0.001) for five-repetition sit-to-stand test, maximal inspiratory pressure and peak oxygen uptake (P<0.001), indicating a training-induced improvement. No major adverse event was noted due to exercise. An 8-week exercise intervention including aerobic, resistance and specific inspiratory muscle training is safe for patients with pulmonary arterial hypertension and yields significant improvements in muscle power and other functional variables. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dietary Methyl Donors Contribute to Whole-Body Protein Turnover and Protein Synthesis in Skeletal Muscle and the Jejunum in Neonatal Piglets.

PubMed

Robinson, Jason L; Harding, Scott V; Brunton, Janet A; Bertolo, Robert F

2016-10-01

The neonatal methionine requirement must consider not only the high demand for rapid tissue protein expansion but also the demands as the precursor for a suite of critical transmethylation reactions. However, methionine metabolism is inherently complex because upon transferring its methyl group during transmethylation, methionine can be reformed by the dietary methyl donors choline (via betaine) and folate. We sought to determine whether dietary methyl donors contribute to methionine availability for protein synthesis in neonatal piglets. Yucatan miniature piglets aged 4-8 d were fed a diet that provided 38 μg folate/(kg·d), 60 mg choline/(kg·d), and 238 mg betaine/(kg·d) [methyl-sufficient (MS); n = 8] or a diet devoid of these methyl precursors [methyl-deficient (MD); n = 8]. After 5 d, dietary methionine was reduced from 0.30 to 0.20 g/(kg·d) in both groups. On day 6, piglets received a constant [1- 13 C]phenylalanine infusion to measure whole-body protein kinetics, and on day 8 they received a constant [ 3 H-methyl]methionine infusion to measure tissue-specific protein synthesis in skeletal muscle, the liver, and the jejunum. Whole-body phenylalanine flux, protein synthesis, and protein breakdown were 13%, 12%, and 22% lower, respectively, in the MD group than in the MS group (P < 0.05). Reduced whole-body protein synthesis in the MD piglets was attributed to 50% lower protein synthesis in skeletal muscle and the jejunum than in the MS piglets (P < 0.05). Furthermore, methionine availability in skeletal muscle was halved in piglets fed the MD diet (P < 0.05), and the specific radioactivity of methionine was doubled in the jejunum of MD piglets (P < 0.05), suggesting lower intestinal remethylation. Liver protein synthesis did not significantly differ between the groups, but secreted proteins were not measured. Dietary methyl donors can affect whole-body and tissue-specific protein synthesis in neonatal piglets and should be considered when determining the methionine requirement. © 2016 American Society for Nutrition.

Smooth muscle myosin light chain kinase efficiently phosphorylates serine 15 of cardiac myosin regulatory light chain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Josephson, Matthew P.; Sikkink, Laura A.; Penheiter, Alan R.

2011-12-16

Highlights: Black-Right-Pointing-Pointer Cardiac myosin regulatory light chain (MYL2) is phosphorylated at S15. Black-Right-Pointing-Pointer Smooth muscle myosin light chain kinase (smMLCK) is a ubiquitous kinase. Black-Right-Pointing-Pointer It is a widely believed that MYL2 is a poor substrate for smMLCK. Black-Right-Pointing-Pointer In fact, smMLCK efficiently and rapidly phosphorylates S15 in MYL2. Black-Right-Pointing-Pointer Phosphorylation kinetics measured by novel fluorescence method without radioactivity. -- Abstract: Specific phosphorylation of the human ventricular cardiac myosin regulatory light chain (MYL2) modifies the protein at S15. This modification affects MYL2 secondary structure and modulates the Ca{sup 2+} sensitivity of contraction in cardiac tissue. Smooth muscle myosin light chainmore » kinase (smMLCK) is a ubiquitous kinase prevalent in uterus and present in other contracting tissues including cardiac muscle. The recombinant 130 kDa (short) smMLCK phosphorylated S15 in MYL2 in vitro. Specific modification of S15 was verified using the direct detection of the phospho group on S15 with mass spectrometry. SmMLCK also specifically phosphorylated myosin regulatory light chain S15 in porcine ventricular myosin and chicken gizzard smooth muscle myosin (S20 in smooth muscle) but failed to phosphorylate the myosin regulatory light chain in rabbit skeletal myosin. Phosphorylation kinetics, measured using a novel fluorescence method eliminating the use of radioactive isotopes, indicates similar Michaelis-Menten V{sub max} and K{sub M} for regulatory light chain S15 phosphorylation rates in MYL2, porcine ventricular myosin, and chicken gizzard myosin. These data demonstrate that smMLCK is a specific and efficient kinase for the in vitro phosphorylation of MYL2, cardiac, and smooth muscle myosin. Whether smMLCK plays a role in cardiac muscle regulation or response to a disease causing stimulus is unclear but it should be considered a potentially significant kinase in cardiac tissue on the basis of its specificity, kinetics, and tissue expression.« less

Differences in skeletal muscle loss caused by cytotoxic chemotherapy and molecular targeted therapy in patients with advanced non-small cell lung cancer.

PubMed

Kakinuma, Kazutaka; Tsuruoka, Hazime; Morikawa, Kei; Furuya, Naoki; Inoue, Takeo; Miyazawa, Teruomi; Mineshita, Masamichi

2018-01-01

Recent studies have revealed a reduction in the skeletal muscle area in patients with advanced non-small cell lung cancer (NSCLC) after chemotherapy. EGFR and ALK tyrosine kinase inhibitor (TKI)-based therapies are less cytotoxic than chemotherapy, but differences in skeletal muscle mass between patients receiving EGFR and ALK TKI therapies and patients receiving cytotoxic chemotherapy have not yet been reported. Data of pathologically proven NSCLC patients were reviewed, and chest computed tomography and/or positron emission tomography-computed tomography images obtained from January 2012 to December 2014 were selected. Patients were divided into two groups: cytotoxic chemotherapy (CG) and molecular targeted (MG). Muscle mass was measured with a single cross-sectional area of the muscle at the third lumber vertebra (L3MA). To estimate skeletal muscle changes during chemotherapy, we defined the following L3 skeletal muscle index (L3SMI) ratio: post L3SMI/pre L3SMI. Differences in the SMI ratio between the groups were evaluated using the Wilcoxon signed-rank test. Sixty-five patients were included in this study: 44 patients received cytotoxic chemotherapy and 21 received molecular targeted therapy (EGFR and ALK TKI). The loss of L3MA in the CG was higher than in the MG (P = 0.03). In the CG, the L3SMI ratio defined to evaluate skeletal muscle mass changes was significantly lower than in the MG (P = 0.0188). Our results suggest that skeletal muscle loss during first-line therapy was significantly different between patients receiving cytotoxic chemotherapy and those receiving TKIs. Specifically, skeletal muscle loss was lower in patients receiving TKIs than in patients receiving cytotoxic chemotherapy. © 2017 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

Vitamin D Receptor gene (VDR) transcripts in bone, cartilage, muscles and blood and microarray analysis of vitamin D responsive genes expression in paravertebral muscles of Juvenile and Adolescent Idiopathic Scoliosis patients

PubMed Central

2012-01-01

Background VDR may be considered as a candidate gene potentially related to Idiopathic Scoliosis susceptibility and natural history. Transcriptional profile of VDR mRNA isoforms might be changed in the structural tissues of the scoliotic spine and potentially influence the expression of VDR responsive genes. The purpose of the study was to determine differences in mRNA abundance of VDR isoforms in bone, cartilage and paravertebral muscles between tissues from curve concavity and convexity, between JIS and AIS and to identify VDR responsive genes differentiating Juvenile and Adolescent Idiopathic Scoliosis in paravertebral muscles. Methods In a group of 29 patients with JIS and AIS, specimens of bone, cartilage, paravertebral muscles were harvested at the both sides of the curve apex together with peripheral blood samples. Extracted total RNA served as a matrix for VDRs and VDRl mRNA quantification by QRT PCR. Subsequent microarray analysis of paravertebral muscular tissue samples was performed with HG U133A chips (Affymetrix). Quantitative data were compared by a nonparametric Mann Whitney U test. Microarray results were analyzed with GeneSpring 11GX application. Matrix plot of normalized log-intensities visualized the degree of differentiation between muscular tissue transcriptomes of JIS and AIS group. Fold Change Analysis with cutoff of Fold Change ≥2 identified differentially expressed VDR responsive genes in paravertebral muscles of JIS and AIS. Results No significant differences in transcript abundance of VDR isoforms between tissues of the curve concavity and convexity were found. Statistically significant difference between JIS and AIS group in mRNA abundance of VDRl isoform was found in paravertebral muscles of curve concavity. Higher degree of muscular transcriptome differentiation between curve concavity and convexity was visualized in JIS group. In paravertebral muscles Tob2 and MED13 were selected as genes differentially expressed in JIS and AIS group. Conclusions In Idiopathic Scolioses transcriptional activity and alternative splicing of VDR mRNA in osseous, cartilaginous, and paravertebral muscular tissues are tissue specific and equal on both sides of the curve. The number of mRNA copies of VDRl izoform in concave paravertebral muscles might be one of the factors differentiating JIS and AIS. In paravertebral muscles Tob2 and Med13 genes differentiate Adolescent and Juvenile type of Idiopathic Scoliosis. PMID:23259508

Effectiveness of Pelvic Floor Muscle Training for Urinary Incontinence: Comparison Within and Between Nonhomebound and Homebound Older Adults.

PubMed

Engberg, Sandra; Sereika, Susan M

2016-01-01

To compare the effectiveness of a biofeedback-taught pelvic floor muscle training (PFMT) intervention in reducing urinary incontinence (UI) and improving general health-related and UI-specific quality of life in homebound and nonhomebound older adults. We also compared adherence rates to the prescribed PFM exercises and strategies (urge and/or stress) in the 2 groups of subjects. Secondary data analysis of initial 6-week PFMT intervention data from a randomized controlled trial designed to examine the efficacy of a relapse prevention intervention in sustaining improvements in UI following PFMT. The sample comprised 93 homebound and 185 nonhomebound community-dwelling men and women 60 years and older with urge, stress, or mixed UI at least twice a week for a minimum of 3 months. The intervention consisted of 6 weekly in-home visits during which biofeedback via transcutaneous electromyographic patches was used to teach subjects pelvic floor muscle exercises and, as indicated, stress and/or urge suppression strategies to prevent involuntary urine loss. Incontinence severity was measured by a 1-week bladder diary at baseline and at the end of the 6-week intervention. Health-related quality of life was measured at baseline and postintervention using the Medical Outcomes Study Short Form-36 (MOS SF-36) (general health-related quality of life), and the Modified Incontinence Impact Questionnaire (MIIQ). Self-reported adherence data were collected at each intervention visit. At baseline, homebound subjects had significantly more severe UI, more comorbid conditions, and higher levels of functional impairment than nonhomebound subjects. Following the intervention, there was a significant reduction in the number of incontinent episodes in both homebound and nonhomebound subjects, with no significant group differences (P = .25) in the median percent reduction in UI (64.5% in homebound vs 70.4% in nonhomebound subjects). UI-specific quality of life (MIIQ total scores) improved significantly in both groups without any significant between-group differences (P = .83). There were no significant changes in health-related quality of life in either group. Pelvic floor muscle adherence rates were higher than adherence rates to strategies in both groups, with no significant group differences. The biofeedback-guided PFMT intervention was equally effective in reducing UI and improving UI-specific quality of life in homebound and nonhomebound community-dwelling older adults.

Cancer cachexia-induced muscle atrophy: evidence for alterations in microRNAs important for muscle size.

PubMed

Lee, David E; Brown, Jacob L; Rosa-Caldwell, Megan E; Blackwell, Thomas A; Perry, Richard A; Brown, Lemuel A; Khatri, Bhuwan; Seo, Dongwon; Bottje, Walter G; Washington, Tyrone A; Wiggs, Michael P; Kong, Byung-Whi; Greene, Nicholas P

2017-05-01

Muscle atrophy is a hallmark of cancer cachexia resulting in impaired function and quality of life and cachexia is the immediate cause of death for 20-40% of cancer patients. Multiple microRNAs (miRNAs) have been identified as being involved in muscle development and atrophy; however, less is known specifically on miRNAs in cancer cachexia. The purpose of this investigation was to examine the miRNA profile of skeletal muscle atrophy induced by cancer cachexia to uncover potential miRNAs involved with this catabolic condition. Phosphate-buffered saline (PBS) or Lewis lung carcinoma cells (LLC) were injected into C57BL/6J mice at 8 wk of age. LLC animals were allowed to develop tumors for 4 wk to induce cachexia. Tibialis anterior muscles were extracted and processed to isolate small RNAs, which were used for miRNA sequencing. Sequencing results were assembled with mature miRNAs, and functions of miRNAs were analyzed by Ingenuity Pathway Analysis. LLC animals developed tumors that contributed to significantly smaller tibialis anterior muscles (18.5%) and muscle cross-sectional area (40%) compared with PBS. We found 371 miRNAs to be present in the muscle above background levels. Of these, nine miRNAs were found to be differentially expressed. Significantly altered groups of miRNAs were categorized into primary functionalities including cancer, cell-to-cell signaling, and cellular development among others. Gene network analysis predicted specific alterations of factors contributing to muscle size including Akt, FOXO3, and others. These results create a foundation for future research into the sufficiency of targeting these genes to attenuate muscle loss in cancer cachexia. Copyright © 2017 the American Physiological Society.

Biomechanics of the osteoporotic spine, pain, and principles of training.

PubMed

Schröder, Guido; Knauerhase, Andreas; Willenberg, Holger S; Kundt, Guenther; Wendig, Detlef; Schober, Hans-Christof

2017-05-01

A fracture is a clinical manifestation of osteoporosis and is one of the main causes of functional limitations and chronic pain in patients with osteoporosis. Muscle and coordination training are recommended to the patients as general measures. We inquired whether sling training is better than traditional physiotherapy in relieving pain and improving abilities of daily living. Fifty patients with osteoporosis were divided into two groups. Group A performed conventional physiotherapy, while Group B performed sling training exercises. Data were collected before and after the intervention and after 3 months. The registered parameters were stamina, posture, and pain. Posture, torques, and the associated strength of spinal muscles were studied in a biomechanical model in order to estimate the forces acting on the spine. Furthermore, the factors that exerted a positive impact on the success of therapy were registered. Forty-four patients (88%) completed the study. Positive effects of the training were noted in both groups, but significantly better effects were observed in the group that performed sling training. A reduction of pain independent of the number of fractures, significantly reduced torques, and reduced muscle strength were registered. Specific training programs helped to increase muscle strength and straightening the back thereby reducing the force needed on a permanent basis and decreasing torque in the spine. Sling training was more effective in that than traditional physiotherapy.

Effect of pelvic floor muscle training compared with watchful waiting in older women with symptomatic mild pelvic organ prolapse: randomised controlled trial in primary care

PubMed Central

Wiegersma, Marian; Panman, Chantal M C R; Kollen, Boudewijn J; Berger, Marjolein Y; Lisman-Van Leeuwen, Yvonne

2014-01-01

Objective To compare the effects of pelvic floor muscle training and watchful waiting on pelvic floor symptoms in a primary care population of women aged 55 years and over with symptomatic mild pelvic organ prolapse. Design Randomised controlled trial. Setting Dutch primary care. Participants Women aged 55 years or over with symptomatic mild prolapse (leading edge above the hymen) were identified by screening. Exclusion criteria were current prolapse treatment or treatment in the previous year, malignancy of pelvic organs, current treatment for another gynaecological disorder, severe/terminal illness, impaired mobility, cognitive impairment, and insufficient command of the Dutch language. Interventions Pelvic floor muscle training versus watchful waiting. Main outcome measures The primary outcome was change in bladder, bowel, and pelvic floor symptoms measured with the Pelvic Floor Distress Inventory-20 (PFDI-20), three months after the start of treatment. Secondary outcomes were changes in condition specific and general quality of life, sexual function, degree of prolapse, pelvic floor muscle function, and patients’ perceived change in symptoms. Results Of the 287 women who were randomised to pelvic floor muscle training (n=145) or watchful waiting (n=142), 250 (87%) completed follow-up. Participants in the intervention group improved by (on average) 9.1 (95% confidence interval 2.8 to 15.4) points more on the PFDI-20 than did participants in the watchful waiting group (P=0.005). Of women in the pelvic floor muscle training group, 57% (82/145) reported an improvement in overall symptoms from the start of the study compared with 13% (18/142) in the watchful waiting group (P<0.001). Other secondary outcomes showed no significant difference between the groups. Conclusions Although pelvic floor muscle training led to a significantly greater improvement in PFDI-20 score, the difference between the groups was below the presumed level of clinical relevance (15 points). Nevertheless, 57% of the participants in the intervention group reported an improvement of overall symptoms. More studies are needed to identify factors related to success of pelvic floor muscle training and to investigate long term effects. Trial registration Dutch Trial Register (www.trialregister.nl) identifier: NTR2047. PMID:25533442

What is new about diet in hepatic encephalopathy.

PubMed

Merli, Manuela; Iebba, Valerio; Giusto, Michela

2016-12-01

There is a relationship between hepatic encephalopathy (HE) protein malnutrition and muscle wasting. Muscle may play an alternative role in ammonia detoxification. Molecular mechanisms responsible for muscle depletion are under investigation. Specific nutrients may interact to reverse the molecular pathways involved in muscle wasting at an early stage. Training exercises have also been proposed to improve skeletal muscle mass. However, these data refer to small groups of patients. The amelioration of muscle mass may potentially help to prevent HE. The pathogenesis of HE is associated with modifications of the gut microbiota and diet is emerging to play a relevant role in the modulation of the gut milieu. Vegetarian and fibre-rich diets have been shown to induce beneficial changes on gut microbiota in healthy people, with reduction of Bacteroides spp., Enterobacteriaceae, and Clostridium cluster XIVa bacteria. By way of contrast, it has been suggested that a high-fat or protein diet may increase Firmicutes and reduce Bacteroidetes phylum. Milk-lysozyme and milk-oligosaccharides have also been proposed to induce a "healthy" microbiota. At present, no studies have been published describing the modification of the gut microbiota in cirrhotic patients with HE as a response to specific diets. New research is needed to evaluate the potentiality of foods in the modulation of gut microbiota in liver disease and HE.

Neck movement and muscle activity characteristics in female office workers with neck pain.

PubMed

Johnston, V; Jull, G; Souvlis, T; Jimmieson, N L

2008-03-01

Cross-sectional study. To explore aspects of cervical musculoskeletal function in female office workers with neck pain. Evidence of physical characteristics that differentiate computer workers with and without neck pain is sparse. Patients with chronic neck pain demonstrate reduced motion and altered patterns of muscle control in the cervical flexor and upper trapezius (UT) muscles during specific tasks. Understanding cervical musculoskeletal function in office workers will better direct intervention and prevention strategies. Measures included neck range of motion; superficial neck flexor muscle activity during a clinical test, the craniocervical flexion test; and a motor task, a unilateral muscle coordination task, to assess the activity of both the anterior and posterior neck muscles. Office workers with and without neck pain were formed into 3 groups based on their scores on the Neck Disability Index. Nonworking women without neck pain formed the control group. Surface electromyographic activity was recorded bilaterally from the sternocleidomastoid, anterior scalene (AS), cervical extensor (CE) and UT muscles. Workers with neck pain had reduced rotation range and increased activity of the superficial cervical flexors during the craniocervical flexion test. During the coordination task, workers with pain demonstrated greater activity in the CE muscles bilaterally. On completion of the task, the UT and dominant CE and AS muscles demonstrated an inability to relax in workers with pain. In general, there was a linear relationship between the workers' self-reported levels of pain and disability and the movement and muscle changes. These results are consistent with those found in other cervical musculoskeletal disorders and may represent an altered muscle recruitment strategy to stabilize the head and neck. An exercise program including motor reeducation may assist in the management of neck pain in office workers.

Specific and cross over effects of massage for muscle soreness: randomized controlled trial.

PubMed

Jay, Kenneth; Sundstrup, Emil; Søndergaard, Stine D; Behm, David; Brandt, Mikkel; Særvoll, Charlotte A; Jakobsen, Markus D; Andersen, Lars L

2014-02-01

Muscle soreness can negatively interfere with the activities of daily living as well as sports performance. In the working environment, a common problem is muscle tenderness, soreness and pain, especially for workers frequently exposed to unilateral high repetitive movements tasks. The aim of the study is therefore to investigate the acute effect of massage applied using a simple device Thera-band roller Massager on laboratory induced hamstring muscle soreness, and the potential cross over effect to the non-massaged limb. 22 healthy untrained men (Mean age 34 +/- 7 years; mean height 181.7 +/- 6.9 cm; mean weight 80.6 +/- 6.4 kg; BMI: 24.5 +/- 1.3) with no prior history of knee, low back or neck injury or other adverse health issues were recruited. Participants visited the researchers on two separate occasions, separated by 48 hours, each time providing a soreness rating (modified visual analog scale 0-10), and being tested for pressure pain threshold (PPT) and active range of motion (ROM) of the hamstring muscles. During the first visit, delayed onset muscular soreness of the hamstring muscles was induced by 10 x 10 repetitions of the stiff-legged dead-lift. On the second visit participants received either 1) 10 minutes of roller massage on one leg, while the contralateral leg served as a cross over control, or 2) Resting for 10 minutes with no massage at all. Measurement of soreness, PPT and ROM were taken immediately before and at 0, 10, 30 and 60 min. after treatment. There was a significant group by time interaction for soreness (p < 0.0001) and PPT (p = 0.0007), with the massage group experiencing reduced soreness and increasing PPT compared with the control group. There was no group by time interaction for ROM (p = 0.18). At 10 min. post massage there was a significant reduction in soreness of the non-massaged limb in the cross over control group compared to controls but this effect was lost 30 minutes post massage. Massage with a roller device reduces muscle soreness and is accompanied by a higher PPT of the affected muscle. 2c; outcomes research.

High-Intensity Strength Training Improves Function of Chronically Painful Muscles: Case-Control and RCT Studies

PubMed Central

Andersen, Christoffer H.; Skotte, Jørgen H.; Suetta, Charlotte; Søgaard, Karen; Saltin, Bengt; Sjøgaard, Gisela

2014-01-01

Aim. This study investigates consequences of chronic neck pain on muscle function and the rehabilitating effects of contrasting interventions. Methods. Women with trapezius myalgia (MYA, n = 42) and healthy controls (CON, n = 20) participated in a case-control study. Subsequently MYA were randomized to 10 weeks of specific strength training (SST, n = 18), general fitness training (GFT, n = 16), or a reference group without physical training (REF, n = 8). Participants performed tests of 100 consecutive cycles of 2 s isometric maximal voluntary contractions (MVC) of shoulder elevation followed by 2 s relaxation at baseline and 10-week follow-up. Results. In the case-control study, peak force, rate of force development, and rate of force relaxation as well as EMG amplitude were lower in MYA than CON throughout all 100 MVC. Muscle fiber capillarization was not significantly different between MYA and CON. In the intervention study, SST improved all force parameters significantly more than the two other groups, to levels comparable to that of CON. This was seen along with muscle fiber hypertrophy and increased capillarization. Conclusion. Women with trapezius myalgia have lower strength capacity during repetitive MVC of the trapezius muscle than healthy controls. High-intensity strength training effectively improves strength capacity during repetitive MVC of the painful trapezius muscle. PMID:24707475

Descending pathways to the cutaneus trunci muscle motoneuronal cell group in the cat

NASA Technical Reports Server (NTRS)

Holstege, Gert; Blok, Bertil F.

1989-01-01

The descending pathways to the motoneuronal cell group of the cutaneous trunci muscle (CTM) of the cat were investigated by injecting H-3-labeled lucine into the brain stem, the diencephalon, or the C1, C2, C6, and C8 segments of the spinal cord, and examining fixed autoradiographic sections of the spinal cord and brain regions. Results demonstrate presence of specific supraspinal projectons to the CTM motor nucleus originating in the contralateral nucleus retroambiguous and the ipsilateral dorsolateral pontine tegmentum. Results also suggest that propriospinal pathways to the CTM motor nucleus originating in the cervical cord do not exist, although these propriospinal projections to all other motoneuronal cell groups surrounding the CTM nucleus are very strong.

Morphological variations of papillary muscles in the mitral valve complex in human cadaveric hearts.

PubMed

Gunnal, Sandhya Arvind; Wabale, Rajendra Namdeo; Farooqui, Mujeebuddin Samsamuddin

2013-01-01

Papillary muscle rupture and dysfunction can lead to complications of prolapsed mitral valve and mitral regurgitation. Multiple operative procedures of the papillary muscles, such as resection, repositioning and realignment, are carried out to restore normal physiological function. Therefore, it is important to know both the variations and the normal anatomy of papillary muscles. This study was carried out on 116 human cadaveric hearts. The left ventricles were opened along the left border in order to view the papillary muscles. The number, shape, position and pattern of the papillary muscles were observed. In this series, the papillary muscles were mostly found in groups instead of in twos, as is described in standard textbooks. Four different shapes of papillary muscles were identified - conical, broad-apexed, pyramidal and fan-shaped. We also discovered various patterns of papillary muscles. No two mitral valve complexes have the same architectural arrangement. Each case seems to be unique. Therefore, it is important for scientists worldwide to study the variations in the mitral valve complex in order to ascertain the reason behind each specific architectural arrangement. This will enable cardiothoracic surgeons to tailor the surgical procedures according to the individual papillary muscle pattern.

Creatine monohydrate supplementation on lower-limb muscle power in Brazilian elite soccer players.

PubMed

Claudino, João G; Mezêncio, Bruno; Amaral, Sérgio; Zanetti, Vinícius; Benatti, Fabiana; Roschel, Hamilton; Gualano, Bruno; Amadio, Alberto C; Serrão, Julio C

2014-01-01

Studies involving chronic creatine supplementation in elite soccer players are scarce. Therefore, the aim of this study was to examine the effects of creatine monohydrate supplementation on lower-limb muscle power in Brazilian elite soccer players (n = 14 males) during pre-season training. This was a randomized, double-blind, placebo-controlled parallel-group study. Brazilian professional elite soccer players participated in this study. During the pre-season (7 weeks), all the subjects underwent a standardized physical and specific soccer training. Prior to and after either creatine monohydrate or placebo supplementation, the lower-limb muscle power was measured by countermovement jump performance. The Jumping performance was compared between groups at baseline (p = 0.99). After the intervention, jumping performance was lower in the placebo group (percent change = - 0.7%; ES = - 0.3) than in the creatine group (percent change = + 2.4%; ES = + 0.1), but it did not reach statistical significance (p = 0.23 for time x group interaction). Fisher's exact test revealed that the proportion of subjects that experienced a reduction in jumping performance was significantly greater in the placebo group than in the creatine group (5 and 1, respectively; p = 0.05) after the training. The magnitude-based inferences demonstrated that placebo resulted in a possible negative effect (50%) in jumping performance, whereas creatine supplementation led to a very likely trivial effect (96%) in jumping performance in the creatine group. Creatine monohydrate supplementation prevented the decrement in lower-limb muscle power in elite soccer players during a pre-season progressive training.

Magnetic Resonance Assessment of Hypertrophic and Pseudo-Hypertrophic Changes in Lower Leg Muscles of Boys with Duchenne Muscular Dystrophy and Their Relationship to Functional Measurements.

PubMed

Vohra, Ravneet S; Lott, Donovan; Mathur, Sunita; Senesac, Claudia; Deol, Jasjit; Germain, Sean; Bendixen, Roxanna; Forbes, Sean C; Sweeney, H Lee; Walter, Glenn A; Vandenborne, Krista

2015-01-01

The primary objectives of this study were to evaluate contractile and non-contractile content of lower leg muscles of boys with Duchenne muscular dystrophy (DMD) and determine the relationships between non-contractile content and functional abilities. Lower leg muscles of thirty-two boys with DMD and sixteen age matched unaffected controls were imaged. Non-contractile content, contractile cross sectional area and non-contractile cross sectional area of lower leg muscles (tibialis anterior, extensor digitorum longus, peroneal, medial gastrocnemius and soleus) were assessed by magnetic resonance imaging (MRI). Muscle strength, timed functional tests and the Brooke lower extremity score were also assessed. Non-contractile content of lower leg muscles (peroneal, medial gastrocnemius, and soleus) was significantly greater than control group (p<0.05). Non-contractile content of lower leg muscles correlated with Brooke score (rs = 0.64-0.84) and 30 feet walk (rs = 0.66-0.80). Dorsiflexor (DF) and plantarflexor (PF) specific torque was significantly different between the groups. Overall, non-contractile content of the lower leg muscles was greater in DMD than controls. Furthermore, there was an age dependent increase in contractile content in the medial gastrocnemius of boys with DMD. The findings of this study suggest that T1 weighted MR images can be used to monitor disease progression and provide a quantitative estimate of contractile and non-contractile content of tissue in children with DMD.

Magnetic Resonance Assessment of Hypertrophic and Pseudo-Hypertrophic Changes in Lower Leg Muscles of Boys with Duchenne Muscular Dystrophy and Their Relationship to Functional Measurements

PubMed Central

Vohra, Ravneet S.; Lott, Donovan; Mathur, Sunita; Senesac, Claudia; Deol, Jasjit; Germain, Sean; Bendixen, Roxanna; Forbes, Sean C.; Sweeney, H. Lee; Walter, Glenn A.; Vandenborne, Krista

2015-01-01

Introduction The primary objectives of this study were to evaluate contractile and non-contractile content of lower leg muscles of boys with Duchenne muscular dystrophy (DMD) and determine the relationships between non-contractile content and functional abilities. Methods Lower leg muscles of thirty-two boys with DMD and sixteen age matched unaffected controls were imaged. Non-contractile content, contractile cross sectional area and non-contractile cross sectional area of lower leg muscles (tibialis anterior, extensor digitorum longus, peroneal, medial gastrocnemius and soleus) were assessed by magnetic resonance imaging (MRI). Muscle strength, timed functional tests and the Brooke lower extremity score were also assessed. Results Non-contractile content of lower leg muscles (peroneal, medial gastrocnemius, and soleus) was significantly greater than control group (p<0.05). Non-contractile content of lower leg muscles correlated with Brooke score (rs = 0.64-0.84) and 30 feet walk (rs = 0.66-0.80). Dorsiflexor (DF) and plantarflexor (PF) specific torque was significantly different between the groups. Discussion Overall, non-contractile content of the lower leg muscles was greater in DMD than controls. Furthermore, there was an age dependent increase in contractile content in the medial gastrocnemius of boys with DMD. The findings of this study suggest that T1 weighted MR images can be used to monitor disease progression and provide a quantitative estimate of contractile and non-contractile content of tissue in children with DMD. PMID:26103164

Fragmented esophageal smooth muscle contraction segments on high resolution manometry: a marker of esophageal hypomotility.

PubMed

Porter, R F; Kumar, N; Drapekin, J E; Gyawali, C P

2012-08-01

Esophageal peristalsis consists of a chain of contracting striated and smooth muscle segments on high resolution manometry (HRM). We compared smooth muscle contraction segments in symptomatic subjects with reflux disease to healthy controls. High resolution manometry Clouse plots were analyzed in 110 subjects with reflux disease (50 ± 1.4 years, 51.5% women) and 15 controls (27 ± 2.1 years, 60.0% women). Using the 30 mmHg isobaric contour tool, sequences were designated fragmented if either smooth muscle contraction segment was absent or if the two smooth muscle segments were separated by a pressure trough, and failed if both smooth muscle contraction segments were absent. The discriminative value of contraction segment analysis was assessed. A total of 1115 swallows were analyzed (reflux group: 965, controls: 150). Reflux subjects had lower peak and averaged contraction amplitudes compared with controls (P < 0.0001 for all comparisons). Fragmented sequences followed 18.4% wet swallows in the reflux group, compared with 7.5% in controls (P < 0.0001), and were seen more frequently than failed sequences (7.9% and 2.5%, respectively). Using a threshold of 30% in individual subjects, a composite of failed and/or fragmented sequences was effective in segregating reflux subjects from control subjects (P = 0.04). Evaluation of smooth muscle contraction segments adds value to HRM analysis. Specifically, fragmented smooth muscle contraction segments may be a marker of esophageal hypomotility. © 2012 Blackwell Publishing Ltd.

Cardiac function in muscular dystrophy associates with abdominal muscle pathology.

PubMed

Gardner, Brandon B; Swaggart, Kayleigh A; Kim, Gene; Watson, Sydeaka; McNally, Elizabeth M

The muscular dystrophies target muscle groups differentially. In mouse models of muscular dystrophy, notably the mdx model of Duchenne Muscular Dystrophy, the diaphragm muscle shows marked fibrosis and at an earlier age than other muscle groups, more reflective of the histopathology seen in human muscular dystrophy. Using a mouse model of limb girdle muscular dystrophy, the Sgcg mouse, we compared muscle pathology across different muscle groups and heart. A cohort of nearly 200 Sgcg mice were studied using multiple measures of pathology including echocardiography, Evans blue dye uptake and hydroxyproline content in multiple muscle groups. Spearman rank correlations were determined among echocardiographic and pathological parameters. The abdominal muscles were found to have more fibrosis than other muscle groups, including the diaphragm muscle. The abdominal muscles also had more Evans blue dye uptake than other muscle groups. The amount of diaphragm fibrosis was found to correlate positively with fibrosis in the left ventricle, and abdominal muscle fibrosis correlated with impaired left ventricular function. Fibrosis in the abdominal muscles negatively correlated with fibrosis in the diaphragm and right ventricles. Together these data reflect the recruitment of abdominal muscles as respiratory muscles in muscular dystrophy, a finding consistent with data from human patients.

Genetic Response of Rat Supraspinatus Tendon and Muscle to Exercise

PubMed Central

Rooney, Sarah Ilkhanipour; Tobias, John W.; Bhatt, Pankti R.; Kuntz, Andrew F.; Soslowsky, Louis J.

2015-01-01

Inflammation is a complex, biologic event that aims to protect and repair tissue. Previous studies suggest that inflammation is critical to induce a healing response following acute injury; however, whether similar inflammatory responses occur as a result of beneficial, non-injurious loading is unknown. The objective of this study was to screen for alterations in a subset of inflammatory and extracellular matrix genes to identify the responses of rat supraspinatus tendon and muscle to a known, non-injurious loading condition. We sought to define how a subset of genes representative of specific inflammation and matrix turnover pathways is altered in supraspinatus tendon and muscle 1) acutely following a single loading bout and 2) chronically following repeated loading bouts. In this study, Sprague-Dawley rats in the acute group ran a single bout of non-injurious exercise on a flat treadmill (10 m/min, 1 hour) and were sacrificed 12 or 24 hours after. Rats in the chronic group ran 5 days/wk for 1 or 8 weeks. A control group maintained normal cage activity. Supraspinatus muscle and tendon were harvested for RNA extractions, and a custom Panomics QuantiGene 2.0 multiplex assay was used to detect 48 target and 3 housekeeping genes. Muscle/tendon and acute/chronic groups had distinct gene expression. Components of the arachidonic acid cascade and matrix metalloproteinases and their inhibitors were altered with acute and chronic exercise. Collagen expression increased. Using a previously validated model of non-injurious exercise, we have shown that supraspinatus tendon and muscle respond to acute and chronic exercise by regulating inflammatory- and matrix turnover-related genes, suggesting that these pathways are involved in the beneficial adaptations to exercise. PMID:26447778

The relationship between muscle action and repetition maximum on the squat and bench press in men and women.

PubMed

Flanagan, Shawn D; Mills, Matthew D; Sterczala, Adam J; Mala, Jesse; Comstock, Brett A; Szivak, Tunde K; DuPont, William H; Looney, David P; McDermott, Danielle M; Hooper, David R; White, Mark T; Dunn-Lewis, Courtenay; Volek, Jeff S; Maresh, Carl M; Kraemer, William J

2014-09-01

The relationship between muscle action and fatigue is not well understood, especially in terms of potential sex-specific differences. The purpose of this investigation was to determine whether a different number of repetitions could be performed on the individual muscle actions of the bench press and squat in men and women. Ten resistance-trained men (n = 10; age, 25.2 ± 1.2 years; height, 178.6 ± 8.8 cm; weight, 91.4 ± 18.1 kg; body fat, 12.7 ± 3.6%) and women (n = 10; age, 25.4 ± 2.4 years; height, 164 ± 4.0 cm; weight, 58.45 ± 3.3 kg; body fat, 20.8 ± 1.5%) participated in this balanced and randomized within-group study. Using 85% of a 1 repetition maximum, over the course of 3 visits, subjects performed 1 eccentric (ECC), concentric (CON), or combined (COMB) set to failure on the squat and bench press. Differences in muscle action and sex-specific number of repetitions to failure were compared on the squat and bench press, where significance was p ≤ 0.05. Across both exercises and sex, we observed significant differences between each of the 3 muscle actions, where the number of repetitions decreased from ECC to COMB to CON. While no sex-specific differences were observed in the squat, women performed significantly more repetitions on the ECC and CON muscle actions of the bench press. Men performed more combined repetitions, however, indicating a greater reliance on the stretch-shortening cycle. Different muscle actions contribute uniquely to the successful performance of a lift and fatigue. These contributions appear to differ in men and women.

Bone strength and muscle properties in postmenopausal women with and without a recent distal radius fracture.

PubMed

Crockett, K; Arnold, C M; Farthing, J P; Chilibeck, P D; Johnston, J D; Bath, B; Baxter-Jones, A D G; Kontulainen, S A

2015-10-01

Distal radius (wrist) fracture (DRF) in women over age 50 years is an early sign of bone fragility. Women with a recent DRF compared to women without DRF demonstrated lower bone strength, muscle density, and strength, but no difference in dual-energy x-ray absorptiometry (DXA) measures, suggesting DXA alone may not be a sufficient predictor for DRF risk. The objective of this study was to investigate differences in bone and muscle properties between women with and without a recent DRF. One hundred sixty-six postmenopausal women (50-78 years) were recruited. Participants were excluded if they had taken bone-altering medications in the past 6 months or had medical conditions that severely affected daily living or the upper extremity. Seventy-seven age-matched women with a fracture in the past 6-24 months (Fx, n = 32) and without fracture (NFx, n = 45) were measured for bone and muscle properties using the nondominant (NFx) or non-fractured limb (Fx). Peripheral quantitative computed tomography (pQCT) was used to estimate bone strength in compression (BSIc) at the distal radius and tibia, bone strength in torsion (SSIp) at the shaft sites, muscle density, and area at the forearm and lower leg. Areal bone mineral density at the ultradistal forearm, spine, and femoral neck was measured by DXA. Grip strength and the 30-s chair stand test were used as estimates of upper and lower extremity muscle strength. Limb-specific between-group differences were compared using multivariate analysis of variance (MANOVA). There was a significant group difference (p < 0.05) for the forearm and lower leg, with the Fx group demonstrating 16 and 19% lower BSIc, 3 and 6% lower muscle density, and 20 and 21% lower muscle strength at the upper and lower extremities, respectively. There were no differences between groups for DXA measures. Women with recent DRF had lower pQCT-derived estimated bone strength at the distal radius and tibia and lower muscle density and strength at both extremities.

Mechanisms underlying ICU muscle wasting and effects of passive mechanical loading

PubMed Central

2012-01-01

Introduction Critically ill ICU patients commonly develop severe muscle wasting and impaired muscle function, leading to delayed recovery, with subsequent increased morbidity and financial costs, and decreased quality of life for survivors. Critical illness myopathy (CIM) is a frequently observed neuromuscular disorder in ICU patients. Sepsis, systemic corticosteroid hormone treatment and post-synaptic neuromuscular blockade have been forwarded as the dominating triggering factors. Recent experimental results from our group using a unique experimental rat ICU model show that the mechanical silencing associated with CIM is the primary triggering factor. This study aims to unravel the mechanisms underlying CIM, and to evaluate the effects of a specific intervention aiming at reducing mechanical silencing in sedated and mechanically ventilated ICU patients. Methods Muscle gene/protein expression, post-translational modifications (PTMs), muscle membrane excitability, muscle mass measurements, and contractile properties at the single muscle fiber level were explored in seven deeply sedated and mechanically ventilated ICU patients (not exposed to systemic corticosteroid hormone treatment, post-synaptic neuromuscular blockade or sepsis) subjected to unilateral passive mechanical loading for 10 hours per day (2.5 hours, four times) for 9 ± 1 days. Results These patients developed a phenotype considered pathognomonic of CIM; that is, severe muscle wasting and a preferential myosin loss (P < 0.001). In addition, myosin PTMs specific to the ICU condition were observed in parallel with an increased sarcolemmal expression and cytoplasmic translocation of neuronal nitric oxide synthase. Passive mechanical loading for 9 ± 1 days resulted in a 35% higher specific force (P < 0.001) compared with the unloaded leg, although it was not sufficient to prevent the loss of muscle mass. Conclusion Mechanical silencing is suggested to be a primary mechanism underlying CIM; that is, triggering the myosin loss, muscle wasting and myosin PTMs. The higher neuronal nitric oxide synthase expression found in the ICU patients and its cytoplasmic translocation are forwarded as a probable mechanism underlying these modifications. The positive effect of passive loading on muscle fiber function strongly supports the importance of early physical therapy and mobilization in deeply sedated and mechanically ventilated ICU patients. PMID:23098317

Towards the resolution of a long-standing evolutionary question: muscle identity and attachments are mainly related to topological position and not to primordium or homeotic identity of digits.

PubMed

Diogo, Rui; Walsh, Sean; Smith, Christopher; Ziermann, Janine M; Abdala, Virginia

2015-06-01

Signaling for limb bone development usually precedes that for muscle development, such that cartilage is generally present before muscle formation. It remains obscure, however, if: (i) tetrapods share a general, predictable spatial correlation between bones and muscles; and, if that is the case, if (ii) such a correlation would reflect an obligatory association between the signaling involved in skeletal and muscle morphogenesis. We address these issues here by using the results of a multidisciplinary analysis of the appendicular muscles of all major tetrapod groups integrating dissections, muscle antibody stainings, regenerative and ontogenetic analyses of fluorescently-labeled (GFP) animals, and studies of non-pentadactyl human limbs related to birth defects. Our synthesis suggests that there is a consistent, surprising anatomical pattern in both normal and abnormal phenotypes, in which the identity and attachments of distal limb muscles are mainly related to the topological position, and not to the developmental primordium (anlage) or even the homeotic identity, of the digits to which they are attached. This synthesis is therefore a starting point towards the resolution of a centuries-old question raised by authors such as Owen about the specific associations between limb bones and muscles. This question has crucial implications for evolutionary and developmental biology, and for human medicine because non-pentadactyly is the most common birth defect in human limbs. In particular, this synthesis paves the way for future developmental experimental and mechanistic studies, which are needed to clarify the processes that may be involved in the elaboration of the anatomical patterns described here, and to specifically test the hypothesis that distal limb muscle identity/attachment is mainly related to digit topology. © 2015 Anatomical Society.

Genetic and environmental influences on skeletal muscle phenotypes as a function of age and sex in large, multigenerational families of African heritage.

PubMed

Prior, Steven J; Roth, Stephen M; Wang, Xiaojing; Kammerer, Candace; Miljkovic-Gacic, Iva; Bunker, Clareann H; Wheeler, Victor W; Patrick, Alan L; Zmuda, Joseph M

2007-10-01

The aim of this study was to estimate the heritability of and environmental contributions to skeletal muscle phenotypes (appendicular lean mass and calf muscle cross-sectional area) in subjects of African descent and to determine whether heritability estimates are impacted by sex or age. Body composition was measured by dual-energy X-ray absorptiometry and computed tomography in 444 men and women aged 18 yr and older (mean: 43 yr) from eight large, multigenerational Afro-Caribbean families (family size range: 21-112). Using quantitative genetic methods, we estimated heritability and the association of anthropometric, lifestyle, and medical variables with skeletal muscle phenotypes. In the overall group, we estimated the heritability of lean mass and calf muscle cross-sectional area (h(2) = 0.18-0.23, P < 0.01) and contribution of environmental factors to these phenotypes (r(2) = 0.27-0.55, P < 0.05). In our age-specific analysis, the heritability of leg lean mass was lower in older vs. younger individuals (h(2) = 0.05 vs. 0.23, respectively, P = 0.1). Sex was a significant covariate in our models (P < 0.001), although sex-specific differences in heritability varied depending on the lean mass phenotype analyzed. High genetic correlations (rho(G) = 0.69-0.81; P < 0.01) between different lean mass measures suggest these traits share a large proportion of genetic components. Our results demonstrate the heritability of skeletal muscle traits in individuals of African heritage and that heritability may differ as a function of sex and age. As the loss of skeletal muscle mass is related to metabolic abnormalities, disability, and mortality in older individuals, further research is warranted to identify specific genetic loci that contribute to these traits in general and in a sex- and age-specific manner.

Effects of soluble milk protein or casein supplementation on muscle fatigue following resistance training program: a randomized, double-blind, and placebo-controlled study

PubMed Central

2014-01-01

Background The effects of protein supplementation on muscle thickness, strength and fatigue seem largely dependent on its composition. The current study compared the effects of soluble milk protein, micellar casein, and a placebo on strength and fatigue during and after a resistance training program. Methods Sixty-eight physically active men participated in this randomized controlled trial and underwent 10 weeks of lower-body resistance training. Participants were randomly assigned to the Placebo (PLA), Soluble Milk Protein (SMP, with fast digestion rate) or Micellar Casein (MC, with slow digestion rate) group. During the 10-week training period, participants were instructed to take 30 g of the placebo or protein twice a day, or three times on training days. Tests were performed on quadriceps muscles at inclusion (PRE), after 4 weeks (MID) and after 10 weeks (POST) of training. They included muscle endurance (maximum number of repetitions during leg extensions using 70% of the individual maximal load), fatigue (decrease in muscle power after the endurance test), strength, power and muscle thickness. Results Muscle fatigue was significantly lower (P < 0.05) in the SMP group at MID and POST (-326.8 ± 114.1 W and -296.6 ± 130.1 W, respectively) as compared with PLA (-439.2 ± 153.9 W and -479.2 ± 138.1 W, respectively) and MC (-415.1 ± 165.1 W and -413.7 ± 139.4 W, respectively). Increases in maximal muscle power, strength, endurance and thickness were not statistically different between groups. Conclusions The present study demonstrated that protein composition has a large influence on muscular performance after prolonged resistance training. More specifically, as compared with placebo or micellar casein, soluble milk protein (fast digestible) appeared to significantly reduce muscle fatigue induced by intense resistance exercise. PMID:25057266

Effects of soluble milk protein or casein supplementation on muscle fatigue following resistance training program: a randomized, double-blind, and placebo-controlled study.

PubMed

Babault, Nicolas; Deley, Gaëlle; Le Ruyet, Pascale; Morgan, François; Allaert, François André

2014-01-01

The effects of protein supplementation on muscle thickness, strength and fatigue seem largely dependent on its composition. The current study compared the effects of soluble milk protein, micellar casein, and a placebo on strength and fatigue during and after a resistance training program. Sixty-eight physically active men participated in this randomized controlled trial and underwent 10 weeks of lower-body resistance training. Participants were randomly assigned to the Placebo (PLA), Soluble Milk Protein (SMP, with fast digestion rate) or Micellar Casein (MC, with slow digestion rate) group. During the 10-week training period, participants were instructed to take 30 g of the placebo or protein twice a day, or three times on training days. Tests were performed on quadriceps muscles at inclusion (PRE), after 4 weeks (MID) and after 10 weeks (POST) of training. They included muscle endurance (maximum number of repetitions during leg extensions using 70% of the individual maximal load), fatigue (decrease in muscle power after the endurance test), strength, power and muscle thickness. Muscle fatigue was significantly lower (P < 0.05) in the SMP group at MID and POST (-326.8 ± 114.1 W and -296.6 ± 130.1 W, respectively) as compared with PLA (-439.2 ± 153.9 W and -479.2 ± 138.1 W, respectively) and MC (-415.1 ± 165.1 W and -413.7 ± 139.4 W, respectively). Increases in maximal muscle power, strength, endurance and thickness were not statistically different between groups. The present study demonstrated that protein composition has a large influence on muscular performance after prolonged resistance training. More specifically, as compared with placebo or micellar casein, soluble milk protein (fast digestible) appeared to significantly reduce muscle fatigue induced by intense resistance exercise.

In Vivo Noninvasive Analysis of Human Forearm Muscle Function and Fatigue: Applications to EVA Operations and Training Maneuvers

NASA Technical Reports Server (NTRS)

Fotedar, L. K.; Marshburn, T.; Quast, M. J.; Feeback, D. L.

1999-01-01

Forearm muscle fatigue is one of the major limiting factors affecting endurance during performance of deep-space extravehicular activity (EVA) by crew members. Magnetic resonance (MR) provides in vivo noninvasive analysis of tissue level metabolism and fluid exchange dynamics in exercised forearm muscles through the monitoring of proton magnetic resonance imaging (MRI) and phosphorus magnetic resonance spectroscopy (P-31-MRS) parameter variations. Using a space glove box and EVA simulation protocols, we conducted a preliminary MRS/MRI study in a small group of human test subjects during submaximal exercise and recovery and following exhaustive exercise. In assessing simulated EVA-related muscle fatigue and function, this pilot study revealed substantial changes in the MR image longitudinal relaxation times (T2) as an indicator of specific muscle activation and proton flux as well as changes in spectral phosphocreatine-to-phosphate (PCr/Pi) levels as a function of tissue bioenergetic potential.

Diagnostic yield of electromyography in children with myopathic disorders.

PubMed

Ghosh, Partha S; Sorenson, Eric J

2014-08-01

Interpretation of pediatric electromyography interpretation in myopathic disorders is technically challenging. We assessed our electromyographic experience with respect to sensitivity and specificity in pediatric myopathy. We did a retrospective chart review of patients ≤18 years between 2009 and 2013. Two hundred twenty-four electromyographic studies were reviewed with the following referral diagnoses: myopathy, muscle weakness, neuromuscular disorders, myositis, myalgia, myoglobinuria, myasthenia, myotonia, cramps, periodic paralysis, hypotonia, and developmental delay. Only children who had an electromyography and muscle biopsy were included for analysis. Patients with neurogenic electromyography and neuromuscular junction disorders were excluded. Myopathic electromyography was defined as short duration, low amplitude, polyphasic motor unit potentials with rapid recruitment. Seventy-two patients were included (age range, 6 months-18 years). The following observations were made: group A: myopathic electromyography or pathognomonic of muscle disease and biopsy or genetically confirmed myopathy (32 cases); group B: myopathic electromyography but biopsy normal or nondiagnostic (12 cases); group C: normal electromyography but biopsy or genetically confirmed myopathy (three cases, all with metabolic myopathy); and group D: electromyography normal and biopsy normal or nondiagnostic (25 cases). The most common diagnoses were congenital myopathy (seven cases), metabolic myopathy (six cases), muscular dystrophy (six cases), genetically confirmed myopathy (five cases), myopathy, undefined (five cases), and inflammatory myopathy (four cases). Pediatric electromyography was 91% sensitive and 67% specific in myopathic disorders. The metabolic myopathies were commonly missed by electromyography. Copyright © 2014 Elsevier Inc. All rights reserved.

Fiber type-specific analysis of AMPK isoforms in human skeletal muscle: advancement in methods via capillary nanoimmunoassay.

PubMed

Tobias, Irene S; Lazauskas, Kara K; Arevalo, Jose A; Bagley, James R; Brown, Lee E; Galpin, Andrew J

2018-04-01

Human skeletal muscle is a heterogeneous mixture of multiple fiber types (FT). Unfortunately, present methods for FT-specific study are constrained by limits of protein detection in single-fiber samples. These limitations beget compensatory resource-intensive procedures, ultimately dissuading investigators from pursuing FT-specific research. Additionally, previous studies neglected hybrid FT, confining their analyses to only pure FT. Here we present novel methods of protein detection across a wider spectrum of human skeletal muscle FT using fully automated capillary nanoimmunoassay (CNIA) technology. CNIA allowed a ~20-fold-lower limit of 5'-AMP-activated protein kinase (AMPK) detection compared with Western blotting. We then performed FT-specific assessment of AMPK expression as a proof of concept. Individual human muscle fibers were mechanically isolated, dissolved, and myosin heavy chain (MHC) fiber typed via SDS-PAGE. Single-fiber samples were combined in pairs and grouped into MHC I, MHC I/IIa, MHC IIa, and MHC IIa/IIx for expression analysis of AMPK isoforms α 1 , α 2 , β 1 , β 2 , γ 2 , and γ 3 with a tubulin loading control. Significant FT-specific differences were found for α 2 (1.7-fold higher in MHC IIa and MHC IIa/IIx vs. others), γ 2 (2.5-fold higher in MHC IIa vs. others), and γ 3 (2-fold higher in MHC IIa and 4-fold higher in MHC IIa/IIx vs. others). Development of a protocol that combines the efficient and sensitive CNIA technology with comprehensive SDS-PAGE fiber typing marks an important advancement in FT-specific research because it allows more precise study of the molecular mechanisms governing metabolism, adaptation, and regulation in human muscle. NEW & NOTEWORTHY We demonstrate the viability of applying capillary nanoimmunoassay technology to the study of fiber type-specific protein analysis in human muscle fibers. This novel technique enables a ~20-fold-lower limit of protein detection compared with traditional Western blotting methods. Combined with SDS-PAGE methods of fiber typing, we apply this technique to compare 5'-AMP-activated protein kinase isoform expression in myosin heavy chain (MHC) I, MHC I/IIa, MHC IIa, and MHC IIa/IIx fiber types.

The forgotten guidelines: cross-sectional analysis of participation in muscle strengthening and balance & co-ordination activities by adults and older adults in Scotland.

PubMed

Strain, Tessa; Fitzsimons, Claire; Kelly, Paul; Mutrie, Nanette

2016-10-21

In 2011, the UK physical activity guidelines were updated to include recommendations for muscle strengthening and balance & coordination (at least two sessions of relevant activities per week). However, monitoring and policy efforts remain focussed on aerobic activity. This study aimed to assess differences by gender and age in the a) prevalence of muscle strengthening and balance & co-ordination guidelines, and b) participation in guideline-specific activities. The sample for the muscle strengthening analyses was 10,488 adult (16-64 years) and 3857 older adult (≥65 years) 2012-2014 Scottish Health Survey respondents. The balance & co-ordination analyses used only the older adult responses. Differences by gender and (where possible) age in guideline prevalence and activity participation were assessed using logistic regression and t-tests. Thirty-one percent of men and 24 % of women met the muscle strengthening guideline, approximately half that of published figures for aerobic physical activity. Nineteen percent of older men and 12 % of older women met the balance & co-ordination guidelines. The oldest age groups were less likely to meet both guidelines compared to the youngest age groups. Differences by gender were only evident for muscle strengthening: more men met the guidelines than women in all age groups, with the largest difference amongst 16-24 year olds (55 % men compared with 40 % women). Participation in relevant activities differed by gender for both guidelines. 'Workout at gym' was the most popular activity to improve muscle strength for men (18 % participated), while swimming was for women (15 % participated). Golf was the most popular activity to improve balance & co-ordination for older men (11 % participated) and aerobics was for older women (6 % participated). Participation decreased in most muscle strengthening activities for both men and women. One exception was golf, where participation levels were as high amongst older men as in younger age groups, although overall levels were low (3 % of all men). Physical activity policy should aim to increase prevalence of these 'forgotten' guidelines, particularly amongst young women (for muscle strengthening) and older age groups (both guidelines). Gender and age participation differences should be considered when designing population-level interventions.

Differences in skeletal muscle loss caused by cytotoxic chemotherapy and molecular targeted therapy in patients with advanced non‐small cell lung cancer

PubMed Central

Tsuruoka, Hazime; Morikawa, Kei; Furuya, Naoki; Inoue, Takeo; Miyazawa, Teruomi; Mineshita, Masamichi

2017-01-01

Background Recent studies have revealed a reduction in the skeletal muscle area in patients with advanced non‐small cell lung cancer (NSCLC) after chemotherapy. EGFR and ALK tyrosine kinase inhibitor (TKI)‐based therapies are less cytotoxic than chemotherapy, but differences in skeletal muscle mass between patients receiving EGFR and ALK TKI therapies and patients receiving cytotoxic chemotherapy have not yet been reported. Methods Data of pathologically proven NSCLC patients were reviewed, and chest computed tomography and/or positron emission tomography‐computed tomography images obtained from January 2012 to December 2014 were selected. Patients were divided into two groups: cytotoxic chemotherapy (CG) and molecular targeted (MG). Muscle mass was measured with a single cross‐sectional area of the muscle at the third lumber vertebra (L3MA). To estimate skeletal muscle changes during chemotherapy, we defined the following L3 skeletal muscle index (L3SMI) ratio: post L3SMI/pre L3SMI. Differences in the SMI ratio between the groups were evaluated using the Wilcoxon signed‐rank test. Results Sixty‐five patients were included in this study: 44 patients received cytotoxic chemotherapy and 21 received molecular targeted therapy (EGFR and ALK TKI). The loss of L3MA in the CG was higher than in the MG (P = 0.03). In the CG, the L3SMI ratio defined to evaluate skeletal muscle mass changes was significantly lower than in the MG (P = 0.0188). Conclusion Our results suggest that skeletal muscle loss during first‐line therapy was significantly different between patients receiving cytotoxic chemotherapy and those receiving TKIs. Specifically, skeletal muscle loss was lower in patients receiving TKIs than in patients receiving cytotoxic chemotherapy. PMID:29067769

Relationships of mercury concentrations across tissue types, muscle regions and fins for two shark species.

PubMed

O'Bryhim, Jason R; Adams, Douglas H; Spaet, Julia L Y; Mills, Gary; Lance, Stacey L

2017-04-01

Mercury (Hg) exposure poses a threat to both fish and human health. Sharks are known to bioaccumulate Hg, however, little is known regarding how Hg is distributed between different tissue groups (e.g. muscle regions, organs). Here we evaluated total mercury (THg) concentrations from eight muscle regions, four fins (first dorsal, left and right pectorals, caudal-from both the inner core and trailing margin of each fin), and five internal organs (liver, kidney, spleen, heart, epigonal organ) from two different shark species, bonnethead (Sphyrna tiburo) and silky shark (Carcharhinus falciformis) to determine the relationships of THg concentrations between and within tissue groups. Total Hg concentrations were highest in the eight muscle regions with no significant differences in THg concentrations between the different muscle regions and muscle types (red and white). Results from tissue collected from any muscle region would be representative of all muscle sample locations. Total Hg concentrations were lowest in samples taken from the fin inner core of the first dorsal, pectoral, and caudal (lower lobe) fins. Mercury concentrations for samples taken from the trailing margin of the dorsal, pectoral, and caudal fins (upper and lower lobe) were also not significantly different from each other for both species. Significant relationships were found between THg concentrations in dorsal axial muscle tissue and the fin inner core, liver, kidney, spleen and heart for both species as well as the THg concentrations between the dorsal fin trailing margin and the heart for the silky shark and all other sampled tissue types for the bonnethead shark. Our results suggest that biopsy sampling of dorsal muscle can provide data that can effectively estimate THg concentrations in specific organs without using more invasive, or lethal methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sensitivity and Specificity of Eustachian Tube Function Tests in Adults

PubMed Central

Doyle, William J.; Swarts, J. Douglas; Banks, Julianne; Casselbrant, Margaretha L; Mandel, Ellen M; Alper, Cuneyt M.

2013-01-01

Objective Determine if Eustachian Tube (ET) function (ETF) tests can identify ears with physician-diagnosed ET dysfunction (ETD) in a mixed population at high sensitivity and specificity and define the inter-relatedness of ETF test parameters. Methods ETF was evaluated using the Forced-Response, Inflation-Deflation, Valsalva and Sniffing tests in 15 control ears of adult subjects after unilateral myringotomy (Group I) and in 23 ears of 19 adult subjects with ventilation tubes inserted for ETD (Group II). Data were analyzed using logistic regression including each parameter independently and then a step-down Discriminant Analysis including all ETF test parameters to predict group assignment. Factor Analysis operating over all parameters was used to explore relatedness. Results The Discriminant Analysis identified 4 ETF test parameters (Valsalva, ET opening pressure, dilatory efficiency and % positive pressure equilibrated) that together correctly assigned ears to Group II at a sensitivity of 95% and a specificity of 83%. Individual parameters representing the efficiency of ET opening during swallowing showed moderately accurate assignments of ears to their respective groups. Three factors captured approximately 98% of the variance among parameters, the first had negative loadings of the ETF structural parameters, the second had positive loadings of the muscle-assisted ET opening parameters and the third had negative loadings of the muscle-assisted ET opening parameters and positive loadings of the structural parameters. Discussion These results show that ETF tests can correctly assign individual ears to physician-diagnosed ETD with high sensitivity and specificity and that ETF test parameters can be grouped into structural-functional categories. PMID:23868429

Motor regulation problems and pain in adults diagnosed with ADHD

PubMed Central

2013-01-01

Background Most children who are diagnosed with attention deficit-hyperactivity disorder (ADHD) have moderate-to-severe motor problems using the Motor Function Neurological Assessment battery (MFNU). The MFNU focuses on specific muscle adjustment problems associated with ADHD, especially motor inhibition problems and high muscle tone. Here we investigated whether adults with ADHD/hyperkinetic disorder (HKD) have similar motor problems. In our clinical experience, adults with ADHD often complain about back, shoulder, hip, and leg pain. We also investigate reported pain in adults with ADHD. Methods Twenty-five adult outpatients diagnosed with ADHD/HKD who were responders to methylphenidate (MPH) were compared to 23 non-ADHD controls on 16 MFNU subtests and using a ‘total score’ (‘TS’) parameter. The MFNU test leader was blinded to group identity. The two groups were also compared using the Pain Drawing and Numerical Pain Rating Scale. Results The adult ADHD group had significantly (p < .001) more motor problems (higher TS) than controls. On the muscle regulation subtests, 36–96% of the ADHD group showed ‘moderate’ to ‘severe’ problems compared to 13–52% of the control group, and 80% of the ADHD group reported widespread pain. Highly significant differences were found between the ADHD and control groups for the variables ‘pain level’ (p < .001) and ‘pain location’ (p < .001). Significant correlations were found between TS and ‘pain location’ and between TS and ‘pain level’. Conclusions These findings suggest that similar to children with ADHD, adults diagnosed with ADHD also have motor inhibition problems and heightened muscle tone. The presence of significantly higher pain levels and more widespread pain in the ADHD group compared to non-ADHD controls might indicate that pain is a long-term secondary effect of heightened muscle tone and restricted movement that can be demonstrated in children and adults by the MFNU battery. PMID:23642255

Biological risk indicators for recurrent non-specific low back pain in adolescents.

PubMed

Jones, M A; Stratton, G; Reilly, T; Unnithan, V B

2005-03-01

A matched case-control study was carried out to evaluate biological risk indicators for recurrent non-specific low back pain in adolescents. Adolescents with recurrent non-specific low back pain (symptomatic; n = 28; mean (SD) age 14.9 (0.7) years) and matched controls (asymptomatic; n = 28; age 14.9 (0.7) years) with no history of non-specific low back pain participated. Measures of stature, mass, sitting height, sexual maturity (Tanner self assessment), lateral flexion of the spine, lumbar sagittal plane mobility (modified Schober), hip range of motion (Leighton flexometer), back and hamstring flexibility (sit and reach), and trunk muscle endurance (number of sit ups) were performed using standardised procedures with established reliability. Backward stepwise logistic regression analysis was performed, with the presence/absence of recurrent low back pain as the dependent variable and the biological measures as the independent variables. Hip range of motion, trunk muscle endurance, lumbar sagittal plane mobility, and lateral flexion of the spine were identified as significant risk indicators of recurrent low back pain (p<0.05). Follow up analysis indicated that symptomatic subjects had significantly reduced lateral flexion of the spine, lumbar sagittal plane mobility, and trunk muscle endurance (p<0.05). Hip range of motion, abdominal muscle endurance, lumbar flexibility, and lateral flexion of the spine were risk indicators for recurrent non-specific low back pain in a group of adolescents. These risk indicators identify the potential for exercise as a primary or secondary prevention method.

Muscular effects of statins in the elderly female: a review

PubMed Central

Bhardwaj, Shilpa; Selvarajah, Shalini; Schneider, Eric B

2013-01-01

Statins have demonstrated substantial benefits in supporting cardiovascular health. Older individuals are more likely to experience the well-known muscle-related side effects of statins compared with younger individuals. Elderly females may be especially vulnerable to statin-related muscle disorder. This review will collate and discuss statin-related muscular effects, examine their molecular and genetic basis, and how these apply specifically to elderly women. Developing strategies to reduce the incidence of statin-induced myopathy in older adult women could contribute to a significant reduction in the overall incidence of statin-induced muscle disorder in this vulnerable group of patients. Reducing statin-related muscle disorder would likely improve overall patient compliance, thereby leading to an increase in improved short- and long-term outcomes associated with appropriate use of statins. PMID:23355775

Histopathological Evaluation of Skeletal Muscle with Specific Reference to Mouse Models of Muscular Dystrophy.

PubMed

Terry, Rebecca L; Wells, Dominic J

2016-12-01

The muscular dystrophies are a diverse group of degenerative diseases for which many mouse models are available. These models are frequently used to assess potential therapeutic interventions and histological evaluation of multiple muscles is an important part of this assessment. Histological evaluation is especially useful when combined with tests of muscle function. This unit describes a protocol for necropsy, processing, cryosectioning, and histopathological evaluation of murine skeletal muscles, which is applicable to both models of muscular dystrophy and other neuromuscular conditions. Key histopathological features of dystrophic muscle are discussed using the mdx mouse (a model of Duchenne muscular dystrophy) as an example. Optimal handling during dissection, processing and sectioning is vital to avoid artifacts that can confound or prevent future analyses. Muscles carefully processed using this protocol are suitable for further evaluation using immunohistochemistry, immunofluorescence, special histochemical stains, and immuoblotting. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

An electromyographic study of the effect of hand grip sizes on forearm muscle activity and golf performance.

PubMed

Sorbie, Graeme G; Hunter, Henry H; Grace, Fergal M; Gu, Yaodong; Baker, Julien S; Ugbolue, Ukadike Chris

2016-01-01

The study describes the differences in surface electromyography (EMG) activity of two forearm muscles in the lead and trail arm at specific phases of the golf swing using a 7-iron with three different grip sizes among amateur and professional golfers. Fifteen right-handed male golfers performed five golf swings using golf clubs with three different grip sizes. Surface EMG was used to measure muscle activity of the extensor carpi radialis brevis (ECRB) and flexor digitorum superficialis (FDS) on both forearms. There were no significant differences in forearm muscle activity when using the three golf grips within the group of 15 golfers (p > 0.05). When using the undersize grip, club head speed significantly increased (p = 0.044). During the backswing and downswing phases, amateurs produced significantly greater forearm muscle activity with all three grip sizes (p < 0.05). In conclusion, forearm muscle activity is not affected by grip sizes. However, club head speed increases when using undersize grips.

PROGRESSIVE RESISTANCE VOLUNTARY WHEEL RUNNING IN THE mdx MOUSE

PubMed Central

Call, Jarrod A.; McKeehen, James N.; Novotny, Susan A.; Lowe, Dawn A.

2012-01-01

Exercise training has been minimally explored as a therapy to mitigate the loss of muscle strength for individuals with Duchenne muscular dystrophy (DMD). Voluntary wheel running is known to elicit beneficial adaptations in the mdx mouse model for DMD. The aim of this study was to examine progressive resistance wheel running in mdx mice by comprehensively testing muscle function before, during, and after a 12-week training period. Male mdx mice at ~4 weeks age were randomized into three groups: Sedentary, Free Wheel, and Resist Wheel. Muscle strength was assessed via in vivo dorsiflexion torque, grip strength, and whole body tension intermittently throughout the training period. Contractility of isolated soleus muscles was analyzed at the study’s conclusion. Both Free and Resist Wheel mice had greater grip strength (~22%) and soleus muscle specific tetanic force (26%) compared with Sedentary mice. This study demonstrates that two modalities of voluntary exercise are beneficial to dystrophic muscle and may help establish parameters for an exercise prescription for DMD. PMID:21104862

The effect of high-intensity circuit training on physical fitness.

PubMed

Schmidt, Dan; Anderson, Kaz; Graff, Marissa; Strutz, Victoria

2016-05-01

The purpose of this study was to examine the effect of a high-intensity circuit training regimen, using only body weight as resistance, on physical fitness. Ninety-six recreationally active college aged subjects (53 female, 43 male) completed the study. Following baseline testing for height and weight, body composition, aerobic fitness, muscle strength and muscle endurance, subjects were randomly assigned to one of three groups: 7-minute circuit training (CT-7), 14-minute circuit training (CT-14), and a non-training control group (C). Subjects in the CT-7 group (females, N.=17; males, N.=15) were asked to complete a seven minute circuit training workout for eight weeks (three workouts per week). The CT-14 group (females, N.=15; males, N.=13) followed the same protocol as CT-7 through the first four weeks. For the second four weeks they increased exercise time to 14 minutes with the same 7 minute circuit performed twice consecutively. Subjects in group C (females, N.=21; males, N.=15) maintained their normal activity levels throughout the course of the study. There were no significant differences between the groups for any variables tested prior to the exercise intervention. A repeated measures analysis of variance revealed statistically significant improvements in muscular endurance (push-ups) for both male and female subjects in the CT-7 and CT-14 groups. Males in the two exercising groups also showed improvement in muscular strength while aerobic capacity increased for females in the CT-14 group. These results suggest that short duration, high intensity circuit training may improve muscle endurance in moderately fit populations. Slight improvements that are gender specific may also be observed in muscle strength as well as aerobic fitness.

Neuromuscular adaptations associated with knee joint angle-specific force change.

PubMed

Noorkõiv, Marika; Nosaka, Kazunori; Blazevich, Anthony J

2014-08-01

Neuromuscular adaptations to joint angle-specific force increases after isometric training have not yet been fully elucidated. This study examined angle-specific neuromuscular adaptations in response to isometric knee extension training at short (SL, joint angle 38.1° ± 3.7°) versus long (LL, 87.5° ± 6.0°) muscle lengths. Sixteen men trained three times a week for 6 wk either at SL (n = 8) or LL (n = 8). Voluntary maximal isometric knee extensor (MVC) force, doublet twitch force, EMG amplitudes (EMG/Mmax), and voluntary activation during MVC force (VA%) were measured at eight knee joint angles (30°-100°) at weeks 0, 3, and 6. Muscle volume and cross-sectional area (CSA) were measured from magnetic resonance imaging scans, and fascicle length (Lf) was assessed using ultrasonography before and after training. Clear joint angle specificity of force increase was seen in SL but not in LL. The 13.4% ± 9.7% (P = 0.01) force increase around the training angle in SL was related to changes in vastus lateralis and vastus medialis EMG/Mmax around the training angle (r = 0.84-0.88, P < 0.05), without changes in the doublet twitch force-angle relation or muscle size. In LL, muscle volume and CSA increased and the changes in CSA at specific muscle regions were correlated with changes in MVC force. A 5.4% ± 4.9% (P = 0.001) increase in Lf found in both groups was not associated with angle-specific force changes. There were no angle-specific changes in VA%. The EMG/Mmax, although not VA%, results suggest that neural adaptations underpinned training-related changes at short quadriceps lengths, but hypertrophic changes predominated after training at long lengths. The findings of this study should contribute to the development of more effective and evidence-based rehabilitation and strength training protocols.

Label-free screening of niche-to-niche variation in satellite stem cells using functionalized pores

NASA Astrophysics Data System (ADS)

Chapman, Matthew R.; Balakrishnan, Karthik; Conboy, Michael J.; Mohanty, Swomitra; Jabart, Eric; Huang, Haiyan; Hack, James; Conboy, Irina M.; Sohn, Lydia L.

2012-02-01

Combinations of surface markers are currently used to identify muscle satellite cells. Using pores functionalized with specific antibodies and measuring the transit time of cells passing through these pores, we discovered remarkable heterogeneity in the expression of these markers in muscle (satellite) stem cells that reside in different single myofibers. Microniche-specific variation in stem cells of the same organ has not been previously described, as bulk analysis does not discriminate between separate myofibers or even separate hind-leg muscle groups. We found a significant population of Sca-1+ satellite cells that form myotubes, thereby demonstrating the myogenic potential of Sca-1+ cells, which are currently excluded in bulk sorting. Finally, using our label-free pore screening technique, we have been able to quantify directly surface expression of Notch1 without activation of the Notch pathway. We show for the first time Notch1-expression heterogeneity in unactivated satellite cells. The discovery of fiber-to-fiber variations prompts new research into the reasons for such diversity in muscle stem cells.

Walking and Running Require Greater Effort from the Ankle than the Knee Extensor Muscles.

PubMed

Kulmala, Juha-Pekka; Korhonen, Marko T; Ruggiero, Luca; Kuitunen, Sami; Suominen, Harri; Heinonen, Ari; Mikkola, Aki; Avela, Janne

2016-11-01

The knee and ankle extensors as human primary antigravity muscle groups are of utmost importance in a wide range of locomotor activities. Yet, we know surprisingly little about how these muscle groups work, and specifically, how close to their maximal capacities they function across different modes and intensity of locomotion. Therefore, to advance our understanding of locomotor constraints, we determined and compared relative operating efforts of the knee and ankle extensors during walking, running, and sprinting. Using an inverse dynamics biomechanical analysis, the muscle forces of the knee and ankle extensors during walking (1.6 m·s), running (4.1 m·s), and sprinting (9.3 m·s) were quantified and then related to maximum forces of the same muscle groups obtained from a reference hopping test that permitted natural elastic limb behavior. During walking, the relative effort of the ankle extensors was almost two times greater compared with the knee extensors (35% ± 6% vs 19% ± 5%, P < 0.001). Changing walking to running decreased the difference in the relative effort between the extensor muscle groups, but still, the ankle extensors operated at a 25% greater level than the knee extensors (84% ± 12% vs 63% ± 17%, P < 0.05). At top speed sprinting, the ankle extensors reached their maximum operating level, whereas the knee extensors still worked well below their limits, showing a 25% lower relative effort compared with the ankle extensors (96% ± 11% vs 72% ± 19%, P < 0.01). Regardless of the mode of locomotion, humans operate at a much greater relative effort at the ankle than knee extensor muscles. As a consequence, the great demand on ankle extensors may be a key biomechanical factor limiting our locomotor ability and influencing the way we locomote and adapt to accommodate compromised neuromuscular system function.

Muscle-Specific Overexpression of PGC-1α Does Not Augment Metabolic Improvements in Response to Exercise and Caloric Restriction

PubMed Central

Wong, Kari E.; Mikus, Catherine R.; Slentz, Dorothy H.; Seiler, Sarah E.; DeBalsi, Karen L.; Ilkayeva, Olga R.; Crain, Karen I.; Kinter, Michael T.; Kien, C. Lawrence; Stevens, Robert D.

2015-01-01

This study used mice with muscle-specific overexpression of PGC-1α, a transcriptional coactivator that promotes mitochondrial biogenesis, to determine whether increased oxidative potential facilitates metabolic improvements in response to lifestyle modification. MCK-PGC1α mice and nontransgenic (NT) littermates were fed a high-fat diet (HFD) for 10 weeks, followed by stepwise exposures to voluntary wheel running (HFD+Ex) and then 25% caloric restriction with exercise (Ex/CR), each for an additional 10 weeks with continued HFD. Running and CR improved weight and glucose control similarly in MCK-PGC1α and NT mice. Sedentary MCK-PGC1α mice were more susceptible to diet-induced glucose intolerance, and insulin action measured in isolated skeletal muscles remained lower in the transgenic compared with the NT group, even after Ex/CR. Comprehensive profiling of >200 metabolites and lipid intermediates revealed dramatic group-specific responses to the intervention but did not produce a lead candidate that tracked with changes in glucose tolerance irrespective of genotype. Instead, principal components analysis identified a chemically diverse metabolite cluster that correlated with multiple measures of insulin responsiveness. These findings challenge the notion that increased oxidative capacity defends whole-body energy homeostasis and suggest that the interplay between mitochondrial performance, lipotoxicity, and insulin action is more complex than previously proposed. PMID:25422105

Whole body vibration training--improving balance control and muscle endurance.

PubMed

Ritzmann, Ramona; Kramer, Andreas; Bernhardt, Sascha; Gollhofer, Albert

2014-01-01

Exercise combined with whole body vibration (WBV) is becoming increasingly popular, although additional effects of WBV in comparison to conventional exercises are still discussed controversially in literature. Heterogeneous findings are attributed to large differences in the training designs between WBV and "control" groups in regard to training volume, load and type. In order to separate the additional effects of WBV from the overall adaptations due to the intervention, in this study, a four-week WBV training setup was compared to a matched intervention program with identical training parameters in both training settings except for the exposure to WBV. In a repeated-measures matched-subject design, 38 participants were assigned to either the WBV group (VIB) or the equivalent training group (CON). Training duration, number of sets, rest periods and task-specific instructions were matched between the groups. Balance, jump height and local static muscle endurance were assessed before and after the training period. The statistical analysis revealed significant interaction effects of group×time for balance and local static muscle endurance (p<0.05). Hence, WBV caused an additional effect on balance control (pre vs. post VIB +13%, p<0.05 and CON +6%, p = 0.33) and local static muscle endurance (pre vs. post VIB +36%, p<0.05 and CON +11%, p = 0.49). The effect on jump height remained insignificant (pre vs. post VIB +3%, p = 0.25 and CON ±0%, p = 0.82). This study provides evidence for the additional effects of WBV above conventional exercise alone. As far as balance and muscle endurance of the lower leg are concerned, a training program that includes WBV can provide supplementary benefits in young and well-trained adults compared to an equivalent program that does not include WBV.

Effects of a Modified German Volume Training Program on Muscular Hypertrophy and Strength.

PubMed

Amirthalingam, Theban; Mavros, Yorgi; Wilson, Guy C; Clarke, Jillian L; Mitchell, Lachlan; Hackett, Daniel A

2017-11-01

Amirthalingam, T, Mavros, Y, Wilson, GC, Clarke, JL, Mitchell, L, and Hackett, DA. Effects of a modified German volume training program on muscular hypertrophy and strength. J Strength Cond Res 31(11): 3109-3119, 2017-German Volume Training (GVT), or the 10 sets method, has been used for decades by weightlifters to increase muscle mass. To date, no study has directly examined the training adaptations after GVT. The purpose of this study was to investigate the effect of a modified GVT intervention on muscular hypertrophy and strength. Nineteen healthy men were randomly assign to 6 weeks of 10 or 5 sets of 10 repetitions for specific compound resistance exercises included in a split routine performed 3 times per week. Total and regional lean body mass, muscle thickness, and muscle strength were measured before and after the training program. Across groups, there were significant increases in lean body mass measures, however, greater increases in trunk (p = 0.043; effect size [ES] = -0.21) and arm (p = 0.083; ES = -0.25) lean body mass favored the 5-SET group. No significant increases were found for leg lean body mass or measures of muscle thickness across groups. Significant increases were found across groups for muscular strength, with greater increases in the 5-SET group for bench press (p = 0.014; ES = -0.43) and lat pull-down (p = 0.003; ES = -0.54). It seems that the modified GVT program is no more effective than performing 5 sets per exercise for increasing muscle hypertrophy and strength. To maximize hypertrophic training effects, it is recommended that 4-6 sets per exercise be performed, as it seems gains will plateau beyond this set range and may even regress due to overtraining.

Whole Body Vibration Training - Improving Balance Control and Muscle Endurance

PubMed Central

Ritzmann, Ramona; Kramer, Andreas; Bernhardt, Sascha; Gollhofer, Albert

2014-01-01

Exercise combined with whole body vibration (WBV) is becoming increasingly popular, although additional effects of WBV in comparison to conventional exercises are still discussed controversially in literature. Heterogeneous findings are attributed to large differences in the training designs between WBV and “control” groups in regard to training volume, load and type. In order to separate the additional effects of WBV from the overall adaptations due to the intervention, in this study, a four-week WBV training setup was compared to a matched intervention program with identical training parameters in both training settings except for the exposure to WBV. In a repeated-measures matched-subject design, 38 participants were assigned to either the WBV group (VIB) or the equivalent training group (CON). Training duration, number of sets, rest periods and task-specific instructions were matched between the groups. Balance, jump height and local static muscle endurance were assessed before and after the training period. The statistical analysis revealed significant interaction effects of group×time for balance and local static muscle endurance (p<0.05). Hence, WBV caused an additional effect on balance control (pre vs. post VIB +13%, p<0.05 and CON +6%, p = 0.33) and local static muscle endurance (pre vs. post VIB +36%, p<0.05 and CON +11%, p = 0.49). The effect on jump height remained insignificant (pre vs. post VIB +3%, p = 0.25 and CON ±0%, p = 0.82). This study provides evidence for the additional effects of WBV above conventional exercise alone. As far as balance and muscle endurance of the lower leg are concerned, a training program that includes WBV can provide supplementary benefits in young and well-trained adults compared to an equivalent program that does not include WBV. PMID:24587114

The Acetyl Group Buffering Action of Carnitine Acetyltransferase Offsets Macronutrient-Induced Lysine Acetylation of Mitochondrial Proteins.

PubMed

Davies, Michael N; Kjalarsdottir, Lilja; Thompson, J Will; Dubois, Laura G; Stevens, Robert D; Ilkayeva, Olga R; Brosnan, M Julia; Rolph, Timothy P; Grimsrud, Paul A; Muoio, Deborah M

2016-01-12

Lysine acetylation (AcK), a posttranslational modification wherein a two-carbon acetyl group binds covalently to a lysine residue, occurs prominently on mitochondrial proteins and has been linked to metabolic dysfunction. An emergent theory suggests mitochondrial AcK occurs via mass action rather than targeted catalysis. To test this hypothesis, we performed mass spectrometry-based acetylproteomic analyses of quadriceps muscles from mice with skeletal muscle-specific deficiency of carnitine acetyltransferase (CrAT), an enzyme that buffers the mitochondrial acetyl-CoA pool by converting short-chain acyl-CoAs to their membrane permeant acylcarnitine counterparts. CrAT deficiency increased tissue acetyl-CoA levels and susceptibility to diet-induced AcK of broad-ranging mitochondrial proteins, coincident with diminished whole body glucose control. Sub-compartment acetylproteome analyses of muscles from obese mice and humans showed remarkable overrepresentation of mitochondrial matrix proteins. These findings reveal roles for CrAT and L-carnitine in modulating the muscle acetylproteome and provide strong experimental evidence favoring the nonenzymatic carbon pressure model of mitochondrial AcK. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

The Acetyl Group Buffering Action of Carnitine Acetyltransferase Offsets Macronutrient-induced Lysine Acetylation of Mitochondrial Proteins

PubMed Central

Davies, Michael N.; Kjalarsdottir, Lilja; Thompson, J. Will; Dubois, Laura G.; Stevens, Robert D.; Ilkayeva, Olga R.; Brosnan, M. Julia; Rolph, Timothy P.; Grimsrud, Paul A.; Muoio, Deborah M.

2016-01-01

Lysine acetylation (AcK), a posttranslational modification wherein a two-carbon acetyl group binds covalently to a lysine residue, occurs prominently on mitochondrial proteins and has been linked to metabolic dysfunction. An emergent theory suggests mitochondrial AcK occurs via mass action rather than targeted catalysis. To test this hypothesis we performed mass spectrometry-based acetylproteomic analyses of quadriceps muscles from mice with skeletal muscle-specific deficiency of carnitine acetyltransferase (CrAT), an enzyme that buffers the mitochondrial acetyl-CoA pool by converting short-chain acyl-CoAs to their membrane permeant acylcarnitine counterparts. CrAT deficiency increased tissue acetyl-CoA levels and susceptibility to diet-induced AcK of broad-ranging mitochondrial proteins, coincident with diminished whole body glucose control. Sub-compartment acetylproteome analyses of muscles from obese mice and humans showed remarkable overrepresentation of mitochondrial matrix proteins. These findings reveal roles for CrAT and L-carnitine in modulating the muscle acetylproteome and provide strong experimental evidence favoring the nonenzymatic carbon pressure model of mitochondrial AcK. PMID:26748706

Investigation of electroacupuncture and manual acupuncture on carnitine and glutathione in muscle.

PubMed

Toda, Shizuo

2011-01-01

Electroacupuncture (EA) and manual acupuncture (MA) have therapeutic effects on muscle fatigue in muscle disease. The deficiencies of carnitine and glutathione induce muscle fatigue. This report investigated the effects of EA and MA on carnitine and glutathione in muscle. After the mice of EA group were fixed in the animal cage, right Zusanli (ST36) and Jiexi (ST41) were acupunctured and stimulated with uniform reinforcing and reducing method by twirling the acupuncture needle for 15 min. And then, the needle handles were connected to an electric stimulator for stimulating the acupoint with dense-sparse waves. After the mice of MA group were fixed in an animal cage, right ST36 and ST41 were acupunctured and allowed for 15 min. The mice of normal control group were not acupunctured and stimulated for 15 min. The mice of all groups were killed for collecting muscle tissue 1 h after the final treatment. Carnitine and glutathione in homogenate of muscle tissue were determined with carnitine (Kainos Laboratories Co., Tokyo, Japan) and glutathione assay kit (Dojin Chemicals Co., Kumamoto, Japan). Carnitine level in muscle tissue of MA group was significantly higher than those of EA group and normal control group. Carnitine level in muscle tissue of EA group was not significantly different from that of normal control group. Glutathione levels in muscle tissue of EA group and MA group were significantly higher than that of normal control group. This report presented that carnitine in muscle is increased by MA, and not increased by EA, and that glutathione in muscle is increased by EA and MA.

Investigation of Electroacupuncture and Manual Acupuncture on Carnitine and Glutathione in Muscle

PubMed Central

Toda, Shizuo

2011-01-01

Electroacupuncture (EA) and manual acupuncture (MA) have therapeutic effects on muscle fatigue in muscle disease. The deficiencies of carnitine and glutathione induce muscle fatigue. This report investigated the effects of EA and MA on carnitine and glutathione in muscle. After the mice of EA group were fixed in the animal cage, right Zusanli (ST36) and Jiexi (ST41) were acupunctured and stimulated with uniform reinforcing and reducing method by twirling the acupuncture needle for 15 min. And then, the needle handles were connected to an electric stimulator for stimulating the acupoint with dense-sparse waves. After the mice of MA group were fixed in an animal cage, right ST36 and ST41 were acupunctured and allowed for 15 min. The mice of normal control group were not acupunctured and stimulated for 15 min. The mice of all groups were killed for collecting muscle tissue 1 h after the final treatment. Carnitine and glutathione in homogenate of muscle tissue were determined with carnitine (Kainos Laboratories Co., Tokyo, Japan) and glutathione assay kit (Dojin Chemicals Co., Kumamoto, Japan). Carnitine level in muscle tissue of MA group was significantly higher than those of EA group and normal control group. Carnitine level in muscle tissue of EA group was not significantly different from that of normal control group. Glutathione levels in muscle tissue of EA group and MA group were significantly higher than that of normal control group. This report presented that carnitine in muscle is increased by MA, and not increased by EA, and that glutathione in muscle is increased by EA and MA. PMID:19592478

Effects of age and inactivity due to prolonged bed rest on atrophy of trunk muscles.

PubMed

Ikezoe, Tome; Mori, Natsuko; Nakamura, Masatoshi; Ichihashi, Noriaki

2012-01-01

This study investigated the effects of age and inactivity due to being chronically bedridden on atrophy of trunk muscles. The subjects comprised 33 young women (young group) and 41 elderly women who resided in nursing homes or chronic care institutions. The elderly subjects were divided into two groups: independent elderly group who were able to perform activities of daily living involving walking independently (n = 28) and dependent elderly group who were chronically bedridden (n = 13). The thickness of the following six trunk muscles was measured by B-mode ultrasound: the rectus abdominis, external oblique, internal oblique, transversus abdominis, thoracic erector spinae (longissimus) and lumbar multifidus muscles. All muscles except for the transversus abdominis and lumbar multifidus muscles were significantly thinner in the independent elderly group compared with those in the young group. The thicknesses of all muscles in the dependent elderly group was significantly smaller than that in the young group, whereas there were no differences between the dependent elderly and independent elderly groups in the muscle thicknesses of the rectus abdominis and internal oblique muscles. In conclusion, our results suggest that: (1) age-related atrophy compared with young women was less in the deep antigravity trunk muscles than the superficial muscles in the independent elderly women; (2) atrophy associated with chronic bed rest was more marked in the antigravity muscles, such as the back and transversus abdominis.

The influence of sodium bicarbonate on maximal force and rates of force development in the triceps surae and brachii during fatiguing exercise.

PubMed

Siegler, Jason C; Mudie, Kurt; Marshall, Paul

2016-11-01

What is the central question of this study? Does metabolic alkalosis in humans, induced by sodium bicarbonate, affect rates of skeletal muscle fatigue differentially in muscle groups composed predominately of slow- and fast-twitch fibres? What is the main finding and its importance? Sodium bicarbonate exhibited no effect on the fatigue profile observed between triceps surae and brachii muscle groups during and after 2 min of tetanic stimulation. For the first time in exercising humans, we have profiled the effect of sodium bicarbonate on the voluntary and involuntary contractile characteristics of muscle groups representative of predominately slow- and fast-twitch fibres. The effect of metabolic alkalosis on fibre-specific maximal force production and rates of force development (RFD) has been investigated previously in animal models, with evidence suggesting an improved capacity to develop force rapidly in fast- compared with slow-twitch muscle. We have attempted to model in vivo the fatigue profile of voluntary and involuntary maximal force and RFD in the triceps surae and brachii after sodium bicarbonate (NaHCO 3 ) ingestion. In a double-blind, three-way repeated-measures design, participants (n = 10) ingested either 0.3 g kg -1 NaHCO 3 (ALK) or equivalent calcium carbonate (PLA) prior to 2 min of continuous (1 Hz) supramaximal stimulation (300 ms at 40 Hz) of the triceps surae or brachii, with maximal voluntary efforts (maximal voluntary torque) coupled with direct muscle stimulation also measured at baseline, 1 and 2 min. Metabolic alkalosis was achieved in both ALK trials but was not different between muscle groups. Regardless of the conditions, involuntary torque declined nearly 60% in the triceps brachii (P < 0.001) and ∼30% in the triceps surae (P < 0.001). In all trials, there was a significant decline in normalized involuntary RFD (P < 0.05). Maximal voluntary torque declined nearly 28% but was not different between conditions (P < 0.01), and although declining nearly 21% in voluntary RFD (P < 0.05) there was no difference between PLA and ALK in either muscle group (P = 0.93). Sodium bicarbonate exhibited no effect on the fatigue observed between representative fibre-type muscle groups on maximal voluntary and involuntary torque or rates of torque development during and after 2 min of tetanic stimulation. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Interaction of thyroid state and denervation on skeletal myosin heavy chain expression

NASA Technical Reports Server (NTRS)

Haddad, F.; Arnold, C.; Zeng, M.; Baldwin, K.

1997-01-01

The goal of this study was to examine the effects of altered thyroid state and denervation (Den) on skeletal myosin heavy chain (MHC) expression in the plantaris and soleus muscles. Rats were subjected to unilateral denervation (Den) and randomly assigned to one of three groups: (1) euthyroid; (2) hyperthyroid; (3) and hypothyroid. Denervation caused severe muscle atrophy and muscle-type specific MHC transformation. Denervation transformed the soleus to a faster muscle, and its effects required the presence of circulating thyroid hormone. In contrast, denervation transformed the plantaris to a slower muscle independently of thyroid state. Furthermore, thyroid hormone effects did not depend upon innervation status in the soleus, while they required the presence of the nerve in the plantaris. Collectively, these findings suggest that both thyroid hormone and intact nerve (a) differentially affect MHC transformations in fast and slow muscle; and (b) are important factors in regulating the optimal expression of both type I and IIB MHC genes. This research suggests that for patients with nerve damage and/or paralysis, both muscle mass and biochemical properties can also be affected by the thyroid state.

The Effect of Functional Mandibular Shift on the Muscle Spindle Systems in Head-Neck Muscles and the Related Neurotransmitter Histamine.

PubMed

Du, Bing-Li; Li, Jiang-Ning; Guo, Hong-Ming; Li, Song; Liu, Biao

2017-09-01

The aim of this study is to explore the effects of abnormal occlusion and functional recovery caused by functional mandible deviation on the head and neck muscles and muscle spindle sensory-motor system by electrophysiological response and endogenous monoamine neurotransmitters' distribution in the nucleus of the spinal tract. Seven-week-old male Wistar rats were randomly divided into 7 groups: normal control group, 2W experimental control group, 2W functional mandible deviation group, 2W functional mandible deviation recovery group, 4W experimental control group, 4W functional mandible deviation group, 4W functional mandible deviation recovery group. Chewing muscles, digastric muscle, splenius, and trapezius muscle spindles electrophysiological response activities at the opening and closing state were recorded. And then the chewing muscles, digastric, splenius, trapezius, and neck trigeminal nucleus were taken for histidine decarboxylase (HDC) detection by high performance liquid chromatography (HPLC), immunofluorescence, and reverse-transcription polymerase chain reaction (RT-PCR). Histamine receptor proteins in the neck nucleus of the spinal tract were also examined by immunofluorescence and RT-PCR. Electromyography activity of chewing muscles, digastric, and splenius muscle was significantly asymmetric; the abnormal muscle electromyography activity was mainly detected at the ipsilateral side. After functional mandibular deviation, muscle sensitivity on the ipsilateral sides of the chewing muscle and splenius decreased, muscle excitement weakened, modulation depth decreased, and the muscle spindle afferent impulses of excitation transmission speed slowed down. Changes for digastric muscle electrical activity were contrary. The functions recovered at different extents after removing the deflector. However, trapezius in all the experimental groups and recovery groups exhibited bilateral symmetry electrophysiological responses, and no significant difference compared with the control group. After functional mandibular deviation, HDC protein and messenger ribonucleic acid (mRNA) levels on the ipsilateral sides of the chewing muscle and splenius increased significantly. HDC level changes for digastric muscle were contrary. After the removal of the mandibular position deflector, HDC protein and mRNA levels decreased on the ipsilateral sides of the chewing muscle and splenius while they increased in the digastric muscle. The difference of histamine decarboxylase content in the bilateral trapezius in each experimental group was small. After functional mandibular deviation, the temporomandibular joint mechanical receptors not only caused the fusimotor fiber hypoallergenic fatigue slow response on the ipsilateral sides of splenius, but also increased the injury neurotransmitter histamine release. The authors' results further support the opinion that the temporomandibular joint receptors may be involved in the mechanical theory of the head and neck muscles nervous system regulation.

Effects of local and widespread muscle fatigue on movement timing.

PubMed

Cowley, Jeffrey C; Dingwell, Jonathan B; Gates, Deanna H

2014-12-01

Repetitive movements can cause muscle fatigue, leading to motor reorganization, performance deficits, and/or possible injury. The effects of fatigue may depend on the type of fatigue task employed, however. The purpose of this study was to determine how local fatigue of a specific muscle group versus widespread fatigue of various muscle groups affected the control of movement timing. Twenty healthy subjects performed an upper extremity low-load work task similar to sawing for 5 continuous minutes both before and after completing a protocol that either fatigued all the muscles used in the task (widespread fatigue) or a protocol that selectively fatigued the primary muscles used to execute the pushing stroke of the sawing task (localized fatigue). Subjects were instructed to time their movements with a metronome. Timing error, movement distance, and speed were calculated for each movement. Data were then analyzed using a goal-equivalent manifold approach to quantify changes in goal-relevant and non-goal-relevant variability. We applied detrended fluctuation analysis to each time series to quantify changes in fluctuation dynamics that reflected changes in the control strategies used. After localized fatigue, subjects made shorter, slower movements and exerted greater control over non-goal-relevant variability. After widespread fatigue, subjects exerted less control over non-goal-relevant variability and did not change movement patterns. Thus, localized and widespread muscle fatigue affected movement differently. Local fatigue may reduce the available motor solutions and therefore cause greater movement reorganization than widespread muscle fatigue. Subjects altered their control strategies but continued to achieve the timing goal after both fatigue tasks.

Endurance exercise training and high-fat diet differentially affect composition of diacylglycerol molecular species in rat skeletal muscle.

PubMed

Kawanishi, Noriaki; Takagi, Kana; Lee, Hyeon-Cheol; Nakano, Daiki; Okuno, Toshiaki; Yokomizo, Takehiko; Machida, Shuichi

2018-06-01

Insulin resistance of peripheral muscle is implicated in the etiology of metabolic syndrome in obesity. Although accumulation of glycerolipids, such as triacylglycerol and diacylglycerol (DAG), in muscle contributes to insulin resistance in obese individuals, endurance-trained athletes also have higher glycerolipid levels but normal insulin sensitivity. We hypothesized that the difference in insulin sensitivity of skeletal muscle between athletes and obese individuals stems from changes in fatty acid composition of accumulated lipids. Here, we evaluated the effects of intense endurance exercise and high-fat diet (HFD) on the accumulation and composition of lipid molecular species in rat skeletal muscle using a lipidomic approach. Sprague-Dawley female rats were randomly assigned to three groups and received either normal diet (ND) in sedentary conditions, ND plus endurance exercise training, or HFD in sedentary conditions. Rats were fed ND or HFD between 4 and 12 wk of age. Rats in the exercise group ran on a treadmill for 120 min/day, 5 days/wk, for 8 wk. Soleus muscle lipidomic profiles were obtained using liquid chromatography/tandem mass spectrometry. Total DAG levels, particularly those of palmitoleate-containing species, were increased in muscle by exercise training. However, whereas the total DAG level in the muscle was also increased by HFD, the levels of DAG molecular species containing palmitoleate were decreased by HFD. The concentration of phosphatidylethanolamine molecular species containing palmitoleate was increased by exercise but decreased by HFD. Our results indicate that although DAG accumulation was similar levels in trained and sedentary obese rats, specific changes in molecular species containing palmitoleate were opposite.

Glucose uptake patterns in exercised skeletal muscles of elite male long-distance and short-distance runners.

PubMed

Tai, Suh-Jun; Liu, Ren-Shyan; Kuo, Ya-Chen; Hsu, Chi-Yang; Chen, Chi-Hsien

2010-04-30

The aim of this study was to determine glucose uptake patterns in exercised skeletal muscles of elite male long-distance and short-distance runners. Positron emission tomography (PET) using 18F-fluoro-2-deoxyglucose (FDG) was performed to determine the patterns of glucose uptake in lower limbs of short-distance (SD group, n=8) and long-distance (LD group, n=8) male runners after a modified 20 min Bruce treadmill test. Magnetic resonance imaging (MRI) was used to delineate the muscle groups in lower limbs. Muscle groups from hip, knee, and ankle movers were measured. The total FDG uptake and the standard uptake value (SUV) for each muscle group were compared between the 2 groups. For the SD and LD runners, the 2 major muscle groups utilizing glucose during running were knee extensors and ankle plantarflexors, which accounted for 49.3 +/- 8.1% (25.1 +/- 4.7% and 24.2 +/- 6.0%) of overall lower extremity glucose uptake for SD group, and 51.3 +/- 8.0% (27.2 +/- 2.7% and 24.0 +/- 8.1%) for LD group. No difference in muscle glucose uptake was noted for other muscle groups. For SD runners, the SUVs for the muscle groups varied from 0.49 +/- 0.27 for the ankle plantarflexors, to 0.20 +/- 0.08 for the hip flexor. For the LD runners, the highest and lowest SUVs were 0.43 +/- 0.15 for the ankle dorsiflexors and 0.21 +/- 0.19 for the hip. For SD and LD groups, no difference in muscle SUV was noted for the muscle groups. However, the SUV ratio between the ankle dorsiflexors and plantarflexors in the LD group was significantly greater than that in the SD group. We thus conclude that the major propelling muscle groups account for approximately 50% of lower limb glucose utilization during running. Thus, the other muscle groups involving maintenance of balance, limb deceleration, and shock absorption utilize an equal amount. This result provides a new insight into glucose distribution in skeletal muscle, suggesting that propellers and supporters are both energetically important during running. Furthermore, for each unit muscle volume, movers of ankle are more glucose-demanding than those of hip.

Human spinal locomotor control is based on flexibly organized burst generators.

PubMed

Danner, Simon M; Hofstoetter, Ursula S; Freundl, Brigitta; Binder, Heinrich; Mayr, Winfried; Rattay, Frank; Minassian, Karen

2015-03-01

Constant drive provided to the human lumbar spinal cord by epidural electrical stimulation can cause local neural circuits to generate rhythmic motor outputs to lower limb muscles in people paralysed by spinal cord injury. Epidural spinal cord stimulation thus allows the study of spinal rhythm and pattern generating circuits without their configuration by volitional motor tasks or task-specific peripheral feedback. To reveal spinal locomotor control principles, we studied the repertoire of rhythmic patterns that can be generated by the functionally isolated human lumbar spinal cord, detected as electromyographic activity from the legs, and investigated basic temporal components shared across these patterns. Ten subjects with chronic, motor-complete spinal cord injury were studied. Surface electromyographic responses to lumbar spinal cord stimulation were collected from quadriceps, hamstrings, tibialis anterior, and triceps surae in the supine position. From these data, 10-s segments of rhythmic activity present in the four muscle groups of one limb were extracted. Such samples were found in seven subjects. Physiologically adequate cycle durations and relative extension- and flexion-phase durations similar to those needed for locomotion were generated. The multi-muscle activation patterns exhibited a variety of coactivation, mixed-synergy and locomotor-like configurations. Statistical decomposition of the electromyographic data across subjects, muscles and samples of rhythmic patterns identified three common temporal components, i.e. basic or shared activation patterns. Two of these basic patterns controlled muscles to contract either synchronously or alternatingly during extension- and flexion-like phases. The third basic pattern contributed to the observed muscle activities independently from these extensor- and flexor-related basic patterns. Each bifunctional muscle group was able to express both extensor- and flexor-patterns, with variable ratios across the samples of rhythmic patterns. The basic activation patterns can be interpreted as central drives implemented by spinal burst generators that impose specific spatiotemporally organized activation on the lumbosacral motor neuron pools. Our data thus imply that the human lumbar spinal cord circuits can form burst-generating elements that flexibly combine to obtain a wide range of locomotor outputs from a constant, repetitive input. It may be possible to use this flexibility to incorporate specific adaptations to gait and stance to improve locomotor control, even after severe central nervous system damage. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Human spinal locomotor control is based on flexibly organized burst generators

PubMed Central

Danner, Simon M.; Hofstoetter, Ursula S.; Freundl, Brigitta; Binder, Heinrich; Mayr, Winfried; Rattay, Frank

2015-01-01

Constant drive provided to the human lumbar spinal cord by epidural electrical stimulation can cause local neural circuits to generate rhythmic motor outputs to lower limb muscles in people paralysed by spinal cord injury. Epidural spinal cord stimulation thus allows the study of spinal rhythm and pattern generating circuits without their configuration by volitional motor tasks or task-specific peripheral feedback. To reveal spinal locomotor control principles, we studied the repertoire of rhythmic patterns that can be generated by the functionally isolated human lumbar spinal cord, detected as electromyographic activity from the legs, and investigated basic temporal components shared across these patterns. Ten subjects with chronic, motor-complete spinal cord injury were studied. Surface electromyographic responses to lumbar spinal cord stimulation were collected from quadriceps, hamstrings, tibialis anterior, and triceps surae in the supine position. From these data, 10-s segments of rhythmic activity present in the four muscle groups of one limb were extracted. Such samples were found in seven subjects. Physiologically adequate cycle durations and relative extension- and flexion-phase durations similar to those needed for locomotion were generated. The multi-muscle activation patterns exhibited a variety of coactivation, mixed-synergy and locomotor-like configurations. Statistical decomposition of the electromyographic data across subjects, muscles and samples of rhythmic patterns identified three common temporal components, i.e. basic or shared activation patterns. Two of these basic patterns controlled muscles to contract either synchronously or alternatingly during extension- and flexion-like phases. The third basic pattern contributed to the observed muscle activities independently from these extensor- and flexor-related basic patterns. Each bifunctional muscle group was able to express both extensor- and flexor-patterns, with variable ratios across the samples of rhythmic patterns. The basic activation patterns can be interpreted as central drives implemented by spinal burst generators that impose specific spatiotemporally organized activation on the lumbosacral motor neuron pools. Our data thus imply that the human lumbar spinal cord circuits can form burst-generating elements that flexibly combine to obtain a wide range of locomotor outputs from a constant, repetitive input. It may be possible to use this flexibility to incorporate specific adaptations to gait and stance to improve locomotor control, even after severe central nervous system damage. PMID:25582580

Co-activation: its association with weakness and specific neurological pathology

PubMed Central

Busse, Monica E; Wiles, Charles M; van Deursen, Robert WM

2006-01-01

Background Net agonist muscle strength is in part determined by the degree of antagonist co-activation. The level of co-activation might vary in different neurological disorders causing weakness or might vary with agonist strength. Aim This study investigated whether antagonist co-activation changed a) with the degree of muscle weakness and b) with the nature of the neurological lesion causing weakness. Methods Measures of isometric quadriceps and hamstrings strength were obtained. Antagonist (hamstring) co-activation during knee extension was calculated as a ratio of hamstrings over quadriceps activity both during an isometric and during a functional sit to stand (STS) task (using kinematics) in groups of patients with extrapyramidal (n = 15), upper motor neuron (UMN) (n = 12), lower motor neuron (LMN) with (n = 18) or without (n = 12) sensory loss, primary muscle or neuromuscular junction disorder (n = 17) and in healthy matched controls (n = 32). Independent t-tests or Mann Witney U tests were used to compare between the groups. Correlations between variables were also investigated. Results In healthy subjects mean (SD) co-activation of hamstrings during isometric knee extension was 11.8 (6.2)% and during STS was 20.5 (12.9)%. In patients, co-activation ranged from 7 to 17% during isometric knee extension and 15 to 25% during STS. Only the extrapyramidal group had lower co-activation levels than healthy matched controls (p < 0.05). Agonist isometric muscle strength and co-activation correlated only in muscle disease (r = -0.6, p < 0.05) and during STS in UMN disorders (r = -0.7, p < 0.5). Conclusion It is concluded that antagonist co-activation does not systematically vary with the site of neurological pathology when compared to healthy matched controls or, in most patient groups, with strength. The lower co-activation levels found in the extrapyramidal group require confirmation and further investigation. Co-activation may be relevant to individuals with muscle weakness. Within patient serial studies in the presence of changing muscle strength may help to understand these relationships more clearly. PMID:17116259

Effects of muscle atrophy on motor control

NASA Technical Reports Server (NTRS)

Stuart, D. G.

1985-01-01

As a biological tissue, muscle adapts to the demands of usage. One traditional way of assessing the extent of this adaptation has been to examine the effects of an altered-activity protocol on the physiological properties of muscles. However, in order to accurately interpret the changes associated with an activity pattern, it is necessary to employ an appropriate control model. A substantial literature exists which reports altered-use effects by comparing experimental observations with those from animals raised in small laboratory cages. Some evidence suggests that small-cage-reared animals actually represent a model of reduced use. For example, laboratory animals subjected to limited physical activity have shown resistance to insulin-induced glucose uptake which can be altered by exercise training. This project concerned itself with the basic mechanisms underlying muscle atrophy. Specifically, the project addressed the issue of the appropriateness of rats raised in conventional-sized cages as experimental models to examine this phenomenon. The project hypothesis was that rats raised in small cages are inappropriate models for the study of muscle atrophy. The experimental protocol involved: 1) raising two populations of rats, one group in conventional (small)-sized cages and the other group in a much larger (133x) cage, from weanling age (21 days) through to young adulthood (125 days); 2) comparison of size- and force-related characteristics of selected test muscles in an acute terminal paradigm.

Moderate-intensity treadmill running promotes expansion of the satellite cell pool in young and old mice.

PubMed

Shefer, Gabi; Rauner, Gat; Stuelsatz, Pascal; Benayahu, Dafna; Yablonka-Reuveni, Zipora

2013-09-01

Satellite cells, the myogenic progenitors located at the myofibre surface, are essential for the repair of adult skeletal muscle. There is ample evidence for an age-linked decline in the number of satellite cells and performance in limb muscles. Hence, an effective means of activating and expanding the satellite cell pool may enhance muscle maintenance and reduce the impact of age-associated muscle deterioration (sarcopaenia). Accordingly, in the present study, we explored the beneficial effects of endurance exercise on satellite cells in young and old mice. Animals were subjected to an 8-week moderate-intensity treadmill-running approach that does not inflict apparent muscle damage (0° inclination, 11.5 m·min(-1) for 30 min·day(-1) , 6 days·week(-1) ). Myofibres of extensor digitorum longus muscles were then isolated from exercised and sedentary mice and used for monitoring the number of satellite cells, as well as for harvesting individual satellite cells for clonal growth assays. We specifically focused on satellite cell pools of single myofibres, with the view that daily wear of muscles probably affects individual myofibres rather than causing overall muscle damage. We found an expansion of the satellite cell pool in the exercised groups compared to the sedentary groups, with the same increase (~ 1.6-fold) in both ages. The results of the present study are in agreement with our findings obtained using rat gastrocnemius, indicating the consistent effect of exercise on satellite cell expansion in limb muscles. The experimental paradigm established in the present study is useful for investigating satellite cell dynamics at the myofibre niche, as well as for broader investigations of the impact of physiologically and pathologically relevant factors on adult myogenesis. © 2013 The Authors Journal compilation © 2013 FEBS.

Evaluation of microRNAs − 208 and 133a/b as differential biomarkers of acute cardiac and skeletal muscle toxicity in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calvano, Jacqueline, E-mail: Jacqueline.Calvano@bm

Conventional circulating biomarkers of cardiac and skeletal muscle (SKM) toxicity lack specificity and/or have a short half-life. MicroRNAs (miRNAs) are currently being assessed as biomarkers of tissue injury based on their long half-life in blood and selective expression in certain tissues. To assess the utility of miRNAs as biomarkers of cardiac and SKM injury, male Sprague–Dawley rats received a single dose of isoproterenol (ISO); metaproterenol (MET); allylamine (AAM); mitoxantrone (MIT); acetaminophen (APAP) or vehicle. Blood and tissues were collected from rats in each group at 4, 24 and 48 h. ISO, MET, and AAM induced cardiac and SKM lesions andmore » APAP induced liver specific lesions. There was no evidence of tissue injury with MIT by histopathology. Serum levels of candidate miRNAs were compared to conventional serum biomarkers of SKM/cardiac toxicity. Increases in heart specific miR-208 only occurred in rats with cardiac lesions alone and were increased for a longer duration than cardiac troponin and FABP3 (cardiac biomarkers). ISO, MET and AAM induced increases in MyL3 and skeletal muscle troponin (sTnl) (SKM biomarkers). MIT induced large increases in sTnl indicative of SKM toxicity, but sTnl levels were also increased in APAP-treated rats that lacked SKM toxicity. Serum levels of miR-133a/b (enriched in cardiac and SKM) increased following ISO, MET, AAM and MIT treatments but were absent in APAP-treated rats. Our results suggest that miR-133a/b are sensitive and specific markers of SKM and cardiac toxicity and that miR-208 used in combination with miR-133a/b can be used to differentiate cardiac from SKM toxicity. - Highlights: • MiR-208 is specifically expressed in rat hearts. • MiR-133a/b are enriched in rat cardiac/skeletal muscle. • MiR-133a/b are sensitive and specific markers of muscle/cardiac toxicity. • MiR-208 can be used to differentiate cardiac toxicity from skeletal muscle toxicity.« less

Therapeutic Effect of Losartan, an Angiotensin II Type 1 Receptor Antagonist, on CCl₄-Induced Skeletal Muscle Injury.

PubMed

Hwang, Ok-Kyung; Park, Jin-Kyu; Lee, Eun-Joo; Lee, Eun-Mi; Kim, Ah-Young; Jeong, Kyu-Shik

2016-02-08

TGF-β1 is known to inhibit muscle regeneration after muscle injury. However, it is unknown if high systemic levels of TGF-β can affect the muscle regeneration process. In the present study, we demonstrated the effect of a CCl₄ intra-peritoneal injection and losartan (an angiotensin II type 1 receptor antagonist) on skeletal muscle (gastrocnemius muscle) injury and regeneration. Male C57BL/6 mice were grouped randomly as follows: control (n = 7), CCl₄-treatment group (n = 7), and CCl₄ + losartan treatment group (n = 7). After CCl₄ treatment for a 16-week period, the animals were sacrificed and analyzed. The expression of dystrophin significantly decreased in the muscle tissues of the control group, as compared with that of the CCl₄ + losartan group (p < 0.01). p(phospho)-Smad2/3 expression significantly increased in the muscles of the control group compared to that in the CCl₄ + losartan group (p < 0.01). The expressions of Pax7, MyoD, and myogenin increased in skeletal muscles of the CCl₄ + losartan group compared to the corresponding levels in the control group (p < 0.01). We hypothesize that systemically elevated TGF-β1 as a result of CCl₄-induced liver injury causes skeletal muscle injury, while losartan promotes muscle repair from injury via blockade of TGF-β1 signaling.

Effect of Botulinum Toxin A on Muscle Healing and its Implications in Aesthetic and Reconstructive Surgery.

PubMed

Silberstein, Eldad; Maor, Ehud; Sukmanov, Oleg; Bogdanov Berezovsky, Alexander; Shoham, Yaron; Krieger, Yuval

2018-04-06

Muscle activity contributes to the enhancement of facial aging deformity, blepharospasm, cerebral palsy spasticity, trismus, torticollis, and other conditions. Myotomy of the involved muscles in order to reduce the deformity has variable success rates due to muscle healing and regeneration of activity. The goal of this study was to investigate whether blocking striated muscle activity with Botulinum toxin (BtxA) during the healing time after myotomy alters the healing process and reduces long-term muscle activity. Eighteen Sprague Dawley rats where divided into 3 groups: group A (n = 7) underwent myotomy of their Latisimus Dorsi muscle; group B (n = 7) underwent myotomy and injection of BtxA into their severed muscle; group C (n = 4) injection of BtxA only. Muscle strength was tested periodically using a grip test. Starting at week 16 and until the termination of study at week 22, group B (Myotomy + BtxA) showed significant reduction in muscle power compared to the two control groups. Addition of BtxA injection into a muscle immediately after myotomy may interfere with muscle healing and contribute to a more successful long-term result.

Muscle fibers are injured at the time of acute and chronic rotator cuff repair.

PubMed

Davis, Max E; Stafford, Patrick L; Jergenson, Matthew J; Bedi, Asheesh; Mendias, Christopher L

2015-01-01

Rotator cuff tears are a common source of shoulder pain and disability. Even after surgical repair, some patients continue to have reduced function and progression of fatty degeneration. Because patients with chronic cuff tears often experience muscle shortening, it is possible that repairing the tendon to its anatomic footprint induces a stretch-induced muscle injury that could contribute to failures of the repair and perhaps ongoing pain. We hypothesized that, compared with acutely torn and repaired muscles, the stretch that is required to repair a chronically torn cuff would result in more muscle fiber damage. Specifically, we asked: (1) Is there muscle fiber damage that occurs from repair of an acutely torn rotator cuff and does it vary by location in the muscle; and (2) is the damage greater in the case of repair of a chronic injury? We used an open surgical approach to create a full-thickness rotator cuff tear in rats, and measured changes in muscle mass, length, and the number of fibers containing the membrane impermeable Evans Blue Dye after acute (1 day) or chronic (28 days) cuff tear or repair in rats. Differences between groups were tested using a one-way ANOVA followed by Tukey's post hoc sorting. Chronic tears resulted in 24% to 35% decreases in mass and a 20% decrease in length. The repair of acutely and chronically torn muscles resulted in damage to 90% of fibers in the distal portion of the muscle. In the proximal portion, no differences between the acutely torn and repaired groups and controls were observed, whereas repairing the chronically torn group resulted in injury to almost 70% of fibers. In a rat model, marked injury to muscle fibers is induced when the tendons of torn rotator cuffs are repaired to their anatomic footprint. In this animal model, we found that repair of chronically torn cuff muscles results in extensive injury throughout the muscle. Based on these findings, we posit that inducing a widespread injury at the time of surgical repair of chronically torn rotator cuff muscles may contribute to the problems of failed repairs or continued progression of fatty degeneration that is observed in some patients that undergo rotator cuff repair. Therapeutic interventions to protect muscle fiber membranes potentially could enhance outcomes for patients undergoing rotator cuff repair. To evaluate this, future studies that evaluate the use of membrane sealing compounds or drugs that upregulate endogenous membrane-sealing proteins are warranted.

Atrophy of the quadriceps muscle in children with a painful hip.

PubMed

Robben, S G; Lequin, M H; Meradji, M; Diepstraten, A F; Hop, W C

1999-09-01

The objective of this study was to determine the degree of muscle wasting of various components of the quadriceps muscle in children with a painful hip. Between January 1994 and September 1997, 327 consecutive children with a unilateral painful hip and/or limping were evaluated prospectively with ultrasonography. Quadriceps thickness was measured on both sides. Moreover, muscle thickness was measured in 59 control subjects. The patients were divided into eight groups; transient synovitis (n = 134), Perthes' disease (n = 35), slipped capital femoral epiphysis (n = 5), osteomyelitis (n = 4), aspecific synovitis (n = 5), rheumatoid arthritis (n = 3) and miscellaneous (n = 16). In 125 patients, no sonographic and radiological abnormalities were found and during follow-up the symptoms disappeared ('no pathology' group). Ipsilateral muscle wasting was present in all patient groups, whereas the control subjects showed no significant difference in muscle thickness between legs. The degree of muscle wasting was compared between transient synovitis, the 'no pathology' group, Perthes' disease and control subjects. For both quadriceps and vastus intermedius muscles, there was a significant difference between these groups, except between control subjects and the 'no pathology' group. For the rectus femoris muscle, there was a significant difference between these groups, except between transient synovitis and 'no pathology'. Muscle wasting showed a positive correlation with duration of symptoms and pre-existing muscle mass. In conclusion, different diseases show different degrees of muscle wasting, and there are different patterns of muscle wasting of various components of the quadriceps femoris muscle.

Postmaximal contraction blood volume responses are blunted in obese and type 2 diabetic subjects in a muscle-specific manner

PubMed Central

Sanchez, Otto A.; Copenhaver, Elizabeth A.; Chance, Marti A.; Fowler, Michael J.; Towse, Theodore F.; Kent-Braun, Jane A.

2011-01-01

The purpose of this study was to determine whether there are differences in postisometric contraction blood volume and oxygenation responses among groups of type 2 diabetes mellitus (T2DM), obese, and lean individuals detectable using MRI. Eight T2DM patients were individually matched by age, sex, and race to non-T2DM individuals with similar body mass index (obese) and lean subjects. Functional MRI was performed using a dual-gradient-recalled echo, echo-planar imaging sequence with a repetition time of 1 s and at two echo times (TE = 6 and 46 ms). Data were acquired before, during, and after 10-s isometric dorsiflexion contractions performed at 50 and 100% of maximal voluntary contraction (MVC) force. MRI signal intensity (SI) changes from the tibialis anterior and extensor digitorum longus muscles were plotted as functions of time for each TE. From each time course, the difference between the minimum and the maximum postcontraction SI (ΔSI) were determined for TE = 6 ms (ΔSI6) and TE = 46 ms (ΔSI46), reflecting variations in blood volume and oxyhemoglobin saturation, respectively. Following 50% MVC contractions, the mean postcontraction ΔSI6 values were similar in the three groups. Following MVC only, and in the EDL muscle only, T2DM and obese participants had ∼56% lower ΔSI6 than the lean individuals. Also following MVC only, the ΔSI46 response in the EDL was lower in T2DM subjects than in lean individuals. These data suggest that skeletal muscle small vessel impairment occurs in T2DM and body mass index-matched subjects, in muscle-specific and contraction intensity-dependent manners. PMID:21572006

Effectiveness of home-based cupping massage compared to progressive muscle relaxation in patients with chronic neck pain--a randomized controlled trial.

PubMed

Lauche, Romy; Materdey, Svitlana; Cramer, Holger; Haller, Heidemarie; Stange, Rainer; Dobos, Gustav; Rampp, Thomas

2013-01-01

Chronic neck pain is a major public health problem with very few evidence-based complementary treatment options. This study aimed to test the efficacy of 12 weeks of a partner-delivered home-based cupping massage, compared to the same period of progressive muscle relaxation in patients with chronic non-specific neck pain. Patients were randomly assigned to self-directed cupping massage or progressive muscle relaxation. They were trained and asked to undertake the assigned treatment twice weekly for 12 weeks. Primary outcome measure was the current neck pain intensity (0-100 mm visual analog scale; VAS) after 12 weeks. Secondary outcome measures included pain on motion, affective pain perception, functional disability, psychological distress, wellbeing, health-related quality of life, pressure pain thresholds and adverse events. Sixty one patients (54.1±12.7 years; 73.8%female) were randomized to cupping massage (n = 30) or progressive muscle relaxation (n = 31). After treatment, both groups showed significantly less pain compared to baseline however without significant group differences. Significant effects in favor of cupping massage were only found for wellbeing and pressure pain thresholds. In conclusion, cupping massage is no more effective than progressive muscle relaxation in reducing chronic non-specific neck pain. Both therapies can be easily used at home and can reduce pain to a minimal clinically relevant extent. Cupping massage may however be better than PMR in improving well-being and decreasing pressure pain sensitivity but more studies with larger samples and longer follow-up periods are needed to confirm these results. ClinicalTrials.gov NCT01500330.

Effectiveness of Home-Based Cupping Massage Compared to Progressive Muscle Relaxation in Patients with Chronic Neck Pain—A Randomized Controlled Trial

PubMed Central

Lauche, Romy; Materdey, Svitlana; Cramer, Holger; Haller, Heidemarie; Stange, Rainer; Dobos, Gustav; Rampp, Thomas

2013-01-01

Chronic neck pain is a major public health problem with very few evidence-based complementary treatment options. This study aimed to test the efficacy of 12 weeks of a partner-delivered home-based cupping massage, compared to the same period of progressive muscle relaxation in patients with chronic non-specific neck pain. Patients were randomly assigned to self-directed cupping massage or progressive muscle relaxation. They were trained and asked to undertake the assigned treatment twice weekly for 12 weeks. Primary outcome measure was the current neck pain intensity (0–100 mm visual analog scale; VAS) after 12 weeks. Secondary outcome measures included pain on motion, affective pain perception, functional disability, psychological distress, wellbeing, health-related quality of life, pressure pain thresholds and adverse events. Sixty one patients (54.1±12.7 years; 73.8%female) were randomized to cupping massage (n = 30) or progressive muscle relaxation (n = 31). After treatment, both groups showed significantly less pain compared to baseline however without significant group differences. Significant effects in favor of cupping massage were only found for wellbeing and pressure pain thresholds. In conclusion, cupping massage is no more effective than progressive muscle relaxation in reducing chronic non-specific neck pain. Both therapies can be easily used at home and can reduce pain to a minimal clinically relevant extent. Cupping massage may however be better than PMR in improving well-being and decreasing pressure pain sensitivity but more studies with larger samples and longer follow-up periods are needed to confirm these results. Trial Registration ClinicalTrials.gov NCT01500330 PMID:23762355

Diagnostic and Prognostic Significance of Serum and Tissue Galectin 3 Expression in Patients with Carcinoma of the Bladder

PubMed Central

Gendy, Hoda El; Madkour, Bothina; Abdelaty, Sara; Essawy, Fayza; Khattab, Dina; Hammam, Olfat; Nour, Hani H.

2014-01-01

Background Galectins are group of proteins found in the cytoplasm, nucleus, cell surface and extracellular matrix. Galectin 3 (Gal-3) displays pathological expression in a variety of processes such as tumorigenesis. Patients and Method 70 patients classified into the control group, cystitis group, transitional cell carcinoma group, and squamous cell carcinoma group were enrolled in this study which aimed to detect the serum level and the intensity of tissue expression of Gal-3. Results Both serum level and tissue expression of Gal-3 were statistically higher in bladder cancer patients compared to the other groups. Gal-3 level expression increased from low to high grade urothelial tumors, with a statistically significant increase of its level and expression between muscle invasive and non-muscle invasive Ta urothelial tumors. Conclusion The serum Gal-3 level is sensitive and specific for the diagnosis of bladder cancer. The prognostic significance of tissue expression is to be confirmed. PMID:26195948

Feedforward responses of transversus abdominis are directionally specific and act asymmetrically: implications for core stability theories.

PubMed

Allison, Garry T; Morris, Sue L; Lay, Brendan

2008-05-01

Experimental laboratory study supplemented with a repeated case study. To examine bilateral muscle activity of the deep abdominals in response to rapid arm raising, specifically to examine the laterality and directional specificity of feedforward responses of the transversus abdominis (TrA). Based on the feedforward responses of trunk muscles during rapid arm movements, authors have concluded that the deep trunk muscles have different control mechanisms compared to the more superficial muscles. It has been proposed that deep trunk muscles such as TrA contribute substantially to the stability of the lumbar spine and that this is achieved through simultaneous bilateral feedforward activation. These inferences are based on unilateral fine-wire electromyographic (EMG) data and there are limited investigations of bilateral responses of the TrA during unilateral arm raising. Bilateral fine-wire and surface EMG data from the anterior deltoid, TrA, obliquus internus (OI), obliquus externus, biceps femoris, erector spinae, and rectus abdominis during repeated arm raises were recorded at 2 kHz. EMG signal linear envelopes were synchronized to the onset of the anterior deltoid. A feedforward window was defined as the period up to 50 ms after the onset of the anterior deltoid, and paired onsets for bilateral muscles were plotted for both left and right arm movements. Trunk muscles from the group data demonstrated differences between sides (laterality), which were systematically altered when alternate arms were raised (directional specificity). This was clearly evident for the TrA but less obvious for the erector spinae. The ipsilateral biceps femoris and obliquus externus, and contralateral OI and TrA, were activated earlier than the alternate side for both right and left arm movements. This was a consistent pattern over a 7-year period for the case study. Data for the rectus abdominis derived from the case study demonstrated little laterality or directionally specific response. This is the first study to show that the feedforward activity of the TrA is specific to the direction of arm movement and not bilaterally symmetrical. The asymmetry of TrA activity during arm raising suggests that the interpretation of the role of TrA as a bilateral stabilizer during anticipatory postural adjustments needs to be revised. Future research needs to examine muscle synergies associated with the asymmetrical function of the TrA and the underlying mechanism associated with low-load stability training. Therapy, level 5.

Molecular Mechanisms Regulating Muscle Fiber Composition Under Microgravity

NASA Technical Reports Server (NTRS)

Rosenthal, Nadia A.

1999-01-01

The overall goal of this project is to reveal the molecular mechanisms underlying the selective and debilitating atrophy of specific skeletal muscle fiber types that accompanies sustained conditions of microgravity. Since little is currently known about the regulation of fiber-specific gene expression programs in mammalian muscle, elucidation of the basic mechanisms of fiber diversification is a necessary prerequisite to the generation of therapeutic strategies for attenuation of muscle atrophy on earth or in space. Vertebrate skeletal muscle development involves the fusion of undifferentiated mononucleated myoblasts to form multinucleated myofibers, with a concomitant activation of muscle-specific genes encoding proteins that form the force-generating contractile apparatus. The regulatory circuitry controlling skeletal muscle gene expression has been well studied in a number of vertebrate animal systems. The goal of this project has been to achieve a similar level of understanding of the mechanisms underlying the further specification of muscles into different fiber types, and the role played by innervation and physical activity in the maintenance and adaptation of different fiber phenotypes into adulthood. Our recent research on the genetic basis of fiber specificity has focused on the emergence of mature fiber types and have implicated a group of transcriptional regulatory proteins, known as E proteins, in the control of fiber specificity. The restriction of E proteins to selected muscle fiber types is an attractive hypothetical mechanism for the generation of muscle fiber-specific patterns of gene expression. To date our results support a model wherein different E proteins are selectively expressed in muscle cells to determine fiber-restricted gene expression. These studies are a first step to define the molecular mechanisms responsible for the shifts in fiber type under conditions of microgravity, and to determine the potential importance of E proteins as upstream targets for the effects of weightlessness. In the past year we have determined that the expression of E Proteins is restricted to specific fiber types by post-transcriptional mechanisms. By far, the most prevalent mechanism of cellular control for achieving post-transcriptional regulation of gene expression is selective proteolysis -through the ubiquitin -proteasome pathway. Steady-state levels of HEB message are similar in all fast and slow skeletal muscle fiber types, yet the protein is restricted to Type IIX fibers. HEB appears to be a nodal point for regulating fiber-specific transcription, as expression of the transcription factor is regulated at the post-transcriptional level. It is not clear at present whether the regulation is at the level of protein synthesis or degradation. We are now poised to evaluate the biological role of ubiquitination in fiber specific-gene expression by controlling the post-transcriptional expression of E Proteins. The use of metabolic labelling and pharmacological inhibitors of the ubiquitin pathway will be used to identify the mode of regulation of the Type IIX expression pattern. The potential role of specific kinases in effecting the restriction of HEB expression will be examined by using both inhibitors and activators. The results of these studies will provide the necessary information to evaluate the biological role of E proteins in controlling fiber type transitions, and in potentially attenuating the atrophic effects of microgravity conditions. We have also recently shown that ectopic expression of the HEB protein transactivates the Type IIX-specific skeletal a-actin reporter. The 218 bp skeletal a-actin promoter drives transgene expression solely in mature Type IIX fibers. A mouse also carrying the transgene MLCI/HEB (which ectopically expresses the E Protein HEB in Type IIB fibers) forces expression of the skeletal a-actin reporter gene in Type IIB fibers. We can now dissect the composition of this fiber-specific cis-element. The skeletal a-actin promoter is quite compact and has been extensively characterized in vitro for activity and binding factors. The single E box may act as a binding target of myogenic factor/HEB heterodimer to allow for IIX expression. The HEB transcription factor may recognize either the precise flanking sequences of the E Box, or perhaps interacting with other proteins bound nearby, and activating expression in Type IIX fibers. This E box will be both ablated, and alternatively, as ablation may well destroy any muscle-specific transcriptional activity, flanking sequences substituted with those surrounding the E box (El) of the myogenin promoter. Modification of fiber-specific transgene expression will be tested in transgenic mice. The results of these studies will provide basic information on the regulatory circuitry underlying fiber specificity, and will form the basis for building appropriate transgenic regulatory cassettes to effect fiber transitions in subsequent experimental manipulations on unweighted muscles.

Isometric and isokinetic hip strength and agonist/antagonist ratios in symptomatic femoroacetabular impingement.

PubMed

Diamond, Laura E; Wrigley, Tim V; Hinman, Rana S; Hodges, Paul W; O'Donnell, John; Takla, Amir; Bennell, Kim L

2016-09-01

This study investigated isometric and isokinetic hip strength in individuals with and without symptomatic femoroacetabular impingement (FAI). The specific aims were to: (i) determine whether differences exist in isometric and isokinetic hip strength measures between groups; (ii) compare hip strength agonist/antagonist ratios between groups; and (iii) examine relationships between hip strength and self-reported measures of either hip pain or function in those with FAI. Cross-sectional. Fifteen individuals (11 males; 25±5 years) with symptomatic FAI (clinical examination and imaging (alpha angle >55° (cam FAI), and lateral centre edge angle >39° and/or positive crossover sign (combined FAI))) and 14 age- and sex-matched disease-free controls (no morphological FAI on magnetic resonance imaging) underwent strength testing. Maximal voluntary isometric contraction strength of hip muscle groups and isokinetic hip internal (IR) and external rotation (ER) strength (20°/s) were measured. Groups were compared with independent t-tests and Mann-Whitney U tests. Participants with FAI had 20% lower isometric abduction strength than controls (p=0.04). There were no significant differences in isometric strength for other muscle groups or peak isokinetic ER or IR strength. The ratio of isometric, but not isokinetic, ER/IR strength was significantly higher in the FAI group (p=0.01). There were no differences in ratios for other muscle groups. Angle of peak IR torque was the only feature correlated with symptoms. Individuals with symptomatic FAI demonstrate isometric hip abductor muscle weakness and strength imbalance in the hip rotators. Strength measurement, including agonist/antagonist ratios, may be relevant for clinical management of FAI. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Expression of collagen and related growth factors in rat tendon and skeletal muscle in response to specific contraction types.

PubMed

Heinemeier, K M; Olesen, J L; Haddad, F; Langberg, H; Kjaer, M; Baldwin, K M; Schjerling, P

2007-08-01

Acute exercise induces collagen synthesis in both tendon and muscle, indicating an adaptive response in the connective tissue of the muscle-tendon unit. However, the mechanisms of this adaptation, potentially involving collagen-inducing growth factors (such as transforming growth factor-beta-1 (TGF-beta-1)), as well as enzymes related to collagen processing, are not clear. Furthermore, possible differential effects of specific contraction types on collagen regulation have not been investigated. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve. RNA was extracted from medial gastrocnemius and Achilles tendon tissue 24 h after the last training bout, and mRNA levels for collagens I and III, TGF-beta-1, connective tissue growth factor (CTGF), lysyl oxidase (LOX), metalloproteinases (MMP-2 and -9) and their inhibitors (TIMP-1 and 2) were measured by Northern blotting and/or real-time PCR. In tendon, expression of TGF-beta-1 and collagens I and III (but not CTGF) increased in response to all types of training. Similarly, enzymes/factors involved in collagen processing were induced in tendon, especially LOX (up to 37-fold), which could indicate a loading-induced increase in cross-linking of tendon collagen. In skeletal muscle, a similar regulation of gene expression was observed, but in contrast to the tendon response, the effect of eccentric training was significantly greater than the effect of concentric training on the expression of several transcripts. In conclusion, the study supports an involvement of TGF-beta-1 in loading-induced collagen synthesis in the muscle-tendon unit and importantly, it indicates that muscle tissue is more sensitive than tendon to the specific mechanical stimulus.

Accelerated skeletal muscle recovery after in vivo polyphenol administration.

PubMed

Myburgh, Kathryn H; Kruger, Maria J; Smith, Carine

2012-09-01

Acute skeletal muscle damage results in fiber disruption, oxidative stress and inflammation. We investigated cell-specific contributions to the regeneration process after contusion-induced damage (rat gastrocnemius muscle) with or without chronic grape seed-derived proanthocyanidolic oligomer (PCO) administration. In this placebo-controlled study, male Wistar rats were subjected to PCO administration for 2 weeks, after which they were subjected to a standardised contusion injury. Supplementation was continued after injury. Immune and satellite cell responses were assessed, as well as oxygen radical absorption capacity and muscle regeneration. PCO administration resulted in a rapid satellite cell response with an earlier peak in activation (Pax7⁺, CD56⁺, at 4 h post-contusion) vs. placebo groups (PLA) (P<.001: CD56⁺ on Day 5 and Pax7⁺ on Day 7). Specific immune-cell responses in PLA followed expected time courses (neutrophil elevation on Day 1; sustained macrophage elevation from Days 3 to 5). PCO dramatically decreased neutrophil elevation to nonsignificant, while macrophage responses were normal in extent, but significantly earlier (peak between Days 1 and 3) and completely resolved by Day 5. Anti-inflammatory cytokine, IL-10, increased significantly only in PCO (Day 3). Muscle fiber regeneration (MHC(f) content and central nuclei) started earlier and was complete by Day 14 in PCO, but not in PLA. Thus, responses by three crucial cell types involved in muscle recovery were affected by in vivo administration of a specific purified polyphenol in magnitude (neutrophil), time course (macrophages), or time course and activation state (satellite cell), explaining faster effective regeneration in the presence of proanthocyanidolic oligomers. Copyright © 2012 Elsevier Inc. All rights reserved.

Effects of pelvic floor muscle training during pregnancy.

PubMed

de Oliveira, Claudia; Lopes, Marco Antonio Borges; Carla Longo e Pereira, Luciana; Zugaib, Marcelo

2007-08-01

The objective of the present study was to evaluate the effect of pelvic floor muscle training in 46 nulliparous pregnant women. The women were divided into 2 groups: an exercise group and a control group. Functional evaluation of the pelvic floor muscle was performed by digital vaginal palpation using the strength scale described by Ortiz and by a perineometer (with and without biofeedback). The functional evaluation of the pelvic floor muscles showed a significant increase in pelvic floor muscle strength during pregnancy in both groups (P < .001). However, the magnitude of the change was greater in the exercise group than in the control group (47.4% vs. 17.3%, P < .001). The study also showed a significant positive correlation (Spearman's test, r = 0.643; P < .001) between perineometry and digital assessment in the strength of pelvic floor muscles. Pelvic floor muscle training resulted in a significant increase in pelvic floor muscle pressure and strength during pregnancy. A significant positive correlation between functional evaluation of the pelvic floor muscle and perineometry was observed during pregnancy.

Adaptation of rat jaw muscle fibers in postnatal development with a different food consistency: an immunohistochemical and electromyographic study.

PubMed

Kawai, Nobuhiko; Sano, Ryota; Korfage, Joannes A M; Nakamura, Saika; Kinouchi, Nao; Kawakami, Emi; Tanne, Kazuo; Langenbach, Geerling E J; Tanaka, Eiji

2010-06-01

The development of the craniofacial system occurs, among other reasons, as a response to functional needs. In particular, the deficiency of the proper masticatory stimulus affects the growth. The purpose of this study was to relate alterations of muscle activity during postnatal development to adaptational changes in the muscle fibers. Fourteen 21-day-old Wistar strain male rats were randomly divided into two groups and fed on either a solid (hard-diet group) or a powder (soft-diet group) diet for 63 days. A radio-telemetric device was implanted to record muscle activity continuously from the superficial masseter, anterior belly of digastric and anterior temporalis muscles. The degree of daily muscle use was quantified by the total duration of muscle activity per day (duty time), the total burst number and their average length exceeding specified levels of the peak activity (5, 20 and 50%). The fiber type composition of the muscles was examined by the myosin heavy chain content of fibers by means of immunohistochemical staining and their cross-sectional area was measured. All muscle fibers were identified as slow type I and fast type IIA, IIX or IIB (respectively, with increasing twitch contraction speed and fatigability). At lower activity levels (exceeding 5% of the peak activity), the duty time of the anterior belly of the digastric muscle was significantly higher in the soft-diet group than in the hard-diet group (P < 0.05). At higher activity levels (exceeding 20 and 50% of the peak activity), the duty time of the superficial masseter muscle in the soft-diet group was significantly lower than that in the hard-diet group (P < 0.05). There was no difference in the duty time of the anterior temporalis muscle at any muscle activity level. The percentage of type IIA fibers of the superficial masseter muscle in the soft-diet group was significantly lower than that in the hard-diet group (P < 0.01) and the opposite was true with regard to type IIB fibers (P < 0.05). The cross-sectional area of type IIX and type IIB fibers of the superficial masseter muscle was significantly smaller in the soft-diet group than in the hard-diet group (P < 0.05). There was no difference in the muscle fiber composition and the cross-sectional area of the anterior belly of the digastric and anterior temporalis muscles. In conclusion, for the jaw muscles of male rats reared on a soft diet, the slow-to-fast transition of muscle fiber was shown in only the superficial masseter muscle. Therefore, the reduction in the amount of powerful muscle contractions could be important for the slow-to-fast transition of the myosin heavy chain isoform in muscle fibers.

A rapid fluorescence assay for danofloxacin in beef muscle: effect of muscle type on limit of quantitation.

PubMed

Schneider, Marilyn J

2008-08-01

A simple, rapid fluorescence screening assay was applied to the analysis of beef muscle for danofloxacin at the U.S. tolerance level of 200 ng/g. Muscle samples were homogenized in acetic acid-acetonitrile, the resultant mixture centrifuged, and fluorescence of the supernatants was then measured. The significant difference between the fluorescence of control muscle sample extracts and extracts of samples fortified at 200 ng/g allowed for successful discrimination between the samples. Setting a threshold level at the average 200 ng/g fortified sample extract fluorescence -3sigma allowed for identification of potentially violative samples. Successful analysis of a group of blind fortified samples over a range of concentrations was accomplished in this manner, without any false-negative results. The limits of quantitation for danofloxacin, as well as enrofloxacin, using this assay were determined in three types of beef muscle (hanging tenderloin, neck, and eye round steak), as well as in serum. Significant differences in limits of quantitation were found among the three different muscle types examined, with hanging tenderloin muscle providing the lowest value. This work not only shows the potential for use of the fluorescence screening assay as an alternative to currently used microbial or antibody-based assays for the analysis of danofloxacin in beef muscle, but also suggests that assays using beef muscle may vary in performance depending on the specific muscle selected for analysis.

Can pelvic floor muscle training improve sexual function in women with pelvic organ prolapse? A randomized controlled trial.

PubMed

Braekken, Ingeborg H; Majida, Memona; Ellström Engh, Marie; Bø, Kari

2015-02-01

Pelvic floor muscle training (PFMT) has level 1 evidence of reducing the size and symptoms associated with pelvic organ prolapse (POP). There is scant knowledge, however, regarding whether PFMT has an effect on sexual function. The aim of the trial was to evaluate the effect of PFMT on sexual function in women with POP. In this randomized controlled trial, 50 women were randomized to an intervention group (6 months of PFMT and lifestyle advice) and 59 women were randomized to a control group (lifestyle advice only). Participants completed a validated POP-specific questionnaire to describe frequency and bother of prolapse, bladder, bowel, and sexual symptoms and answered a semi-structured interview. No significant change in number of women being sexually active was reported. There were no significant differences between groups regarding change in satisfaction with frequency of intercourse. Interview data revealed that 19 (39%) of women in the PFMT group experienced improved sexual function vs. two (5%) in the control group (P<0.01). Specific improvements reported by some of the women were increased control, strength and awareness of the pelvic floor, improved self-confidence, sensation of a "tighter" vagina, improved libido and orgasms, resolution of pain with intercourse, and heightened sexual gratification for partners. Women who described improved sexual function demonstrated the greatest increases in pelvic floor muscle (PFM) strength (mean 16 ± 10 cmH2 0) and endurance (mean 150 ± 140 cmH2 0s) (P<0.01). PFMT can improve sexual function in some women. Women reporting improvement in sexual function demonstrated the greatest increase in PFM strength and endurance. © 2014 International Society for Sexual Medicine.

Which Treatment is More Effective for Functional Ankle Instability: Strengthening or Combined Muscle Strengthening and Proprioceptive Exercises?

PubMed

Kim, Ki-Jong; Kim, Young-Eok; Jun, Hyun-Ju; Lee, Jin-Su; Ji, Sung-Ha; Ji, Sang-Goo; Seo, Tae-Hwa; Kim, Young-Ok

2014-03-01

[Purpose] The purpose of this study was to implement combined muscle strengthening and proprioceptive exercises to examine the effects of combined exercises on functional ankle instability. [Subjects and Methods] Experiments were conducted with 30 adult males and females. The study subjects were randomly assigned to either a control group (Group A), a muscle strengthening exercise group (Group B), or a combined muscle strengthening and proprioceptive exercise group (Group C) consisting of 10 subjects each. In Group A, measurements were only conducted before and after the experiment without any intervention, whereas the exercise programs for Group B and Group C were implemented three days per week for four weeks. [Results] Muscle strength showed significant increases in Groups B and C compared with the control group during plantar flexion, dorsiflexion, inversion, and eversion. The Cumberland ankle instability tool showed significant increases in Group B and Group C compared with Group A and significant increases in Group C compared with Group B. [Conclusion] Applying combined muscle strengthening and proprioceptive exercises to those who have functional ankle instability is more effective than applying only muscle strengthening exercises.

Influence of fixed muscle length and contractile properties on atrophy and subsequent recovery in the rat soleus and plantaris muscles.

PubMed

Fujita, Naoto; Arakawa, Takamitsu; Matsubara, Takako; Ando, Hiroshi; Miki, Akinori

2009-01-01

This study examined muscular atrophy and the recovery process induced by hindlimb unloading and joint immobilization in the rat soleus and plantaris muscles. Rats were divided into control, hindlimb unloading (HU), hindlimb unloading with ankle joint immobilization at the maximum dorsiflexion (HUD), and maximum plantarflexion (HUP) groups. The hindlimb was reloaded after fourteen days of unloading, and muscle atrophy and walking ability were assessed at 0, 3, and 7 days of reloading. A cross sectional area of muscle fibers in the soleus muscle on day 0 of reloading revealed sizes in order from the control, HUD, HUP down to the HU group, indicating that the HU group was the most atrophied among the four groups. These values in the plantaris muscle ranged in order from the control, HU, HUD, to HUP groups, the HUP group being the most atrophied among the four groups. These muscles recovered from atrophy in the same descending order, and the values in the HUD and HUP groups slowly recovered during the reloading periods. The HUD and HUP groups showed a central core lesion and reloading-induced lesions in some type I muscle fibers after the immobilization and reloading, one possible reason for the delayed recovery in these groups. The muscle atrophy in the HU, HUD, and HUP groups remained at day 7 although the walking ability appeared to be normal. Accordingly, further rehabilitation therapy might be necessary even if the functional ability appears to be normal.

Distribution and severity of weakness among patients with polymyositis, dermatomyositis and juvenile dermatomyositis

PubMed Central

Harris-Love, M. O.; Shrader, J. A.; Koziol, D.; Pahlajani, N.; Jain, M.; Smith, M.; Cintas, H. L.; McGarvey, C. L.; James-Newton, L.; Pokrovnichka, A.; Moini, B.; Cabalar, I.; Lovell, D. J.; Wesley, R.; Plotz, P. H.; Miller, F. W.; Hicks, J. E.

2009-01-01

Objective. To describe the distribution and severity of muscle weakness using manual muscle testing (MMT) in 172 patients with PM, DM and juvenile DM (JDM). The secondary objectives included characterizing individual muscle group weakness and determining associations of weakness with functional status and myositis characteristics in this large cohort of patients with myositis. Methods. Strength was assessed for 13 muscle groups using the 10-point MMT and expressed as a total score, subscores based on functional and anatomical regions, and grades for individual muscle groups. Patient characteristics and secondary outcomes, such as clinical course, muscle enzymes, corticosteroid dosage and functional status were evaluated for association with strength using univariate and multivariate analyses. Results. A gradient of proximal weakness was seen, with PM weakest, DM intermediate and JDM strongest among the three myositis clinical groups (P ≤ 0.05). Hip flexors, hip extensors, hip abductors, neck flexors and shoulder abductors were the muscle groups with the greatest weakness among all three clinical groups. Muscle groups were affected symmetrically. Conclusions. Axial and proximal muscle impairment was reflected in the five weakest muscles shared by our cohort of myositis patients. However, differences in the pattern of weakness were observed among all three clinical groups. Our findings suggest a greater severity of proximal weakness in PM in comparison with DM. PMID:19074186

Effects of nandrolone on recovery after neurotization of chronically denervated muscle in a rat model.

PubMed

Isaacs, Jonathan; Feher, Joseph; Shall, Mary; Vota, Scott; Fox, Michael A; Mallu, Satya; Razavi, Ashkon; Friebe, Ilvy; Shah, Sagar; Spita, Nathalie

2013-10-01

Suboptimal recovery following repair of major peripheral nerves has been partially attributed to denervation atrophy. Administration of anabolic steroids in conjunction with neurotization may improve functional recovery of chronically denervated muscle. The purpose of this study was to evaluate the effect of the administration of nandrolone on muscle recovery following prolonged denervation in a rat model. Eight groups of female Sprague-Dawley rats (15 rats per group, 120 in all) were divided into 3- or 6-month denervated hind limb and sham surgery groups and, then, nandrolone treatment groups and sham treatment groups. Evaluation of treatment effects included nerve conduction, force of contraction, comparative morphology, histology (of muscle fibers), protein electrophoresis (for muscle fiber grouping), and immunohistochemical evaluation. Although a positive trend was noted, neither reinnervated nor normal muscle showed a statistically significant increase in peak muscle force following nandrolone treatment. Indirect measures, including muscle mass (weight and diameter), muscle cell size, muscle fiber type, and satellite cell counts, all failed to support significant anabolic effect. There does not seem to be a functional benefit from nandrolone treatment following reinnervation of either mild or moderately atrophic muscle (related to prolonged denervation) in a rodent model.

Muscle co-contraction patterns in robot-mediated force field learning to guide specific muscle group training.

PubMed

Pizzamiglio, Sara; Desowska, Adela; Shojaii, Pegah; Taga, Myriam; Turner, Duncan L

2017-01-01

Muscle co-contraction is a strategy of increasing movement accuracy and stability employed in dealing with force perturbation of movement. It is often seen in neuropathological populations. The direction of movement influences the pattern of co-contraction, but not all movements are easily achievable for populations with motor deficits. Manipulating the direction of the force instead, may be a promising rehabilitation protocol to train movement with use of a co-contraction reduction strategy. Force field learning paradigms provide a well described procedure to evoke and test muscle co-contraction. The aim of this study was to test the muscle co-contraction pattern in a wide range of arm muscles in different force-field directions utilising a robot-mediated force field learning paradigm of motor adaptation. Forty-two participants volunteered to participate in a study utilising robot-mediated force field motor adaptation paradigm with a clockwise or counter-clockwise force field. Kinematics and surface electromyography (EMG) of eight arm muscles were measured. Both muscle activation and co-contraction was earlier and stronger in flexors in the clockwise condition and in extensors in the counter-clockwise condition. Manipulating the force field direction leads to changes in the pattern of muscle co-contraction.

The biomechanical effects of variation in the maximum forces exerted by trunk muscles on the joint forces and moments in the lumbar spine: a finite element analysis.

PubMed

Kim, K; Lee, S K; Kim, Y H

2010-10-01

The weakening of trunk muscles is known to be related to a reduction of the stabilization function provided by the muscles to the lumbar spine; therefore, strengthening deep muscles might reduce the possibility of injury and pain in the lumbar spine. In this study, the effect of variation in maximum forces of trunk muscles on the joint forces and moments in the lumbar spine was investigated. Accordingly, a three-dimensional finite element model of the lumbar spine that included the trunk muscles was used in this study. The variation in maximum forces of specific muscle groups was then modelled, and joint compressive and shear forces, as well as resultant joint moments, which were presumed to be related to spinal stabilization from a mechanical viewpoint, were analysed. The increase in resultant joint moments occurred owing to decrease in maximum forces of the multifidus, interspinales, intertransversarii, rotatores, iliocostalis, longissimus, psoas, and quadratus lumborum. In addition, joint shear forces and resultant joint moments were reduced as the maximum forces of deep muscles were increased. These results from finite element analysis indicate that the variation in maximum forces exerted by trunk muscles could affect the joint forces and joint moments in the lumbar spine.

Comparative Skeletal Muscle Proteomics Using Two-Dimensional Gel Electrophoresis

PubMed Central

Murphy, Sandra; Dowling, Paul; Ohlendieck, Kay

2016-01-01

The pioneering work by Patrick H. O’Farrell established two-dimensional gel electrophoresis as one of the most important high-resolution protein separation techniques of modern biochemistry (Journal of Biological Chemistry 1975, 250, 4007–4021). The application of two-dimensional gel electrophoresis has played a key role in the systematic identification and detailed characterization of the protein constituents of skeletal muscles. Protein changes during myogenesis, muscle maturation, fibre type specification, physiological muscle adaptations and natural muscle aging were studied in depth by the original O’Farrell method or slightly modified gel electrophoretic techniques. Over the last 40 years, the combined usage of isoelectric focusing in the first dimension and sodium dodecyl sulfate polyacrylamide slab gel electrophoresis in the second dimension has been successfully employed in several hundred published studies on gel-based skeletal muscle biochemistry. This review focuses on normal and physiologically challenged skeletal muscle tissues and outlines key findings from mass spectrometry-based muscle proteomics, which was instrumental in the identification of several thousand individual protein isoforms following gel electrophoretic separation. These muscle-associated protein species belong to the diverse group of regulatory and contractile proteins of the acto-myosin apparatus that forms the sarcomere, cytoskeletal proteins, metabolic enzymes and transporters, signaling proteins, ion-handling proteins, molecular chaperones and extracellular matrix proteins. PMID:28248237

Attenuation of Skeletal Muscle and Renal Injury to the Lower Limb following Ischemia-Reperfusion Using mPTP Inhibitor NIM-811

PubMed Central

Garbaisz, David; Turoczi, Zsolt; Aranyi, Peter; Fulop, Andras; Rosero, Oliver; Hermesz, Edit; Ferencz, Agnes; Lotz, Gabor; Harsanyi, Laszlo; Szijarto, Attila

2014-01-01

Introduction Operation on the infrarenal aorta and large arteries of the lower extremities may cause rhabdomyolysis of the skeletal muscle, which in turn may induce remote kidney injury. NIM-811 (N-metyl-4-isoleucine-cyclosporine) is a mitochondria specific drug, which can prevent ischemic-reperfusion (IR) injury, by inhibiting mitochondrial permeability transition pores (mPTP). Objectives Our aim was to reduce damages in the skeletal muscle and the kidney after IR of the lower limb with NIM-811. Materials and methods Wistar rats underwent 180 minutes of bilateral lower limb ischemia and 240 minutes of reperfusion. Four animal groups were formed called Sham (receiving vehicle and sham surgery), NIM-Sham (receiving NIM-811 and sham surgery), IR (receiving vehicle and surgery), and NIM-IR (receiving NIM-811 and surgery). Serum, urine and histological samples were taken at the end of reperfusion. NADH-tetrazolium staining, muscle Wet/Dry (W/D) ratio calculations, laser Doppler-flowmetry (LDF) and mean arterial pressure (MAP) monitoring were performed. Renal peroxynitrite concentration, serum TNF-α and IL-6 levels were measured. Results Less significant histopathological changes were observable in the NIM-IR group as compared with the IR group. Serum K+ and necroenzyme levels were significantly lower in the NIM-IR group than in the IR group (LDH: p<0.001; CK: p<0.001; K+: p = 0.017). Muscle mitochondrial viability proved to be significantly higher (p = 0.001) and renal function parameters were significantly better (creatinine: p = 0.016; FENa: p<0.001) in the NIM-IR group in comparison to the IR group. Serum TNF-α and IL-6 levels were significantly lower (TNF-α: p = 0.003, IL-6: p = 0.040) as well as W/D ratio and peroxynitrite concentration were significantly lower (p = 0.014; p<0.001) in the NIM-IR group than in the IR group. Conclusion NIM-811 could have the potential of reducing rhabdomyolysis and impairment of the kidney after lower limb IR injury. PMID:24968303

Attenuation of skeletal muscle and renal injury to the lower limb following ischemia-reperfusion using mPTP inhibitor NIM-811.

PubMed

Garbaisz, David; Turoczi, Zsolt; Aranyi, Peter; Fulop, Andras; Rosero, Oliver; Hermesz, Edit; Ferencz, Agnes; Lotz, Gabor; Harsanyi, Laszlo; Szijarto, Attila

2014-01-01

Operation on the infrarenal aorta and large arteries of the lower extremities may cause rhabdomyolysis of the skeletal muscle, which in turn may induce remote kidney injury. NIM-811 (N-metyl-4-isoleucine-cyclosporine) is a mitochondria specific drug, which can prevent ischemic-reperfusion (IR) injury, by inhibiting mitochondrial permeability transition pores (mPTP). Our aim was to reduce damages in the skeletal muscle and the kidney after IR of the lower limb with NIM-811. Wistar rats underwent 180 minutes of bilateral lower limb ischemia and 240 minutes of reperfusion. Four animal groups were formed called Sham (receiving vehicle and sham surgery), NIM-Sham (receiving NIM-811 and sham surgery), IR (receiving vehicle and surgery), and NIM-IR (receiving NIM-811 and surgery). Serum, urine and histological samples were taken at the end of reperfusion. NADH-tetrazolium staining, muscle Wet/Dry (W/D) ratio calculations, laser Doppler-flowmetry (LDF) and mean arterial pressure (MAP) monitoring were performed. Renal peroxynitrite concentration, serum TNF-α and IL-6 levels were measured. Less significant histopathological changes were observable in the NIM-IR group as compared with the IR group. Serum K+ and necroenzyme levels were significantly lower in the NIM-IR group than in the IR group (LDH: p<0.001; CK: p<0.001; K+: p = 0.017). Muscle mitochondrial viability proved to be significantly higher (p = 0.001) and renal function parameters were significantly better (creatinine: p = 0.016; FENa: p<0.001) in the NIM-IR group in comparison to the IR group. Serum TNF-α and IL-6 levels were significantly lower (TNF-α: p = 0.003, IL-6: p = 0.040) as well as W/D ratio and peroxynitrite concentration were significantly lower (p = 0.014; p<0.001) in the NIM-IR group than in the IR group. NIM-811 could have the potential of reducing rhabdomyolysis and impairment of the kidney after lower limb IR injury.

The effect of bridge exercise method on the strength of rectus abdominis muscle and the muscle activity of paraspinal muscles while doing treadmill walking with high heels.

PubMed

Kang, Taewook; Lee, Jaeseok; Seo, Junghoon; Han, Dongwook

2017-04-01

[Purpose] The purpose of this research is to investigate the effect of the method of bridge exercise on the change of rectus abdominis muscle and the muscle activity of paraspinal muscles while doing treadmill walking with high heels. [Subjects and Methods] The subjects of this research are healthy female students consisting of 10 persons performing bridge exercises in a supine group, 10 persons performing bridge exercises in a prone group, and 10 persons in a control group while in S university in Busan. Bridge exercise in supine position is performed in hook lying position. Bridge exercise in prone position is plank exercise in prostrate position. To measure the strength of rectus abdominis muscle, maintaining times of the posture was used. To measure the muscle activity of paraspinal muscles, EMG (4D-MT & EMD-11, Relive, Korea) was used. [Results] The strength of rectus abdominis muscle of both bridge exercises in the supine group and bridge exercises in the prone group increases significantly after exercise. The muscle activity of paraspinal muscle such as thoracic parts and lumbar parts in bridge exercises in the prone group decreases statistically while walking on a treadmill with high heels. Muscle activity of thoracic parts paraspinal muscle and bridge exercises in the supine group decreased significantly. [Conclusion] According to this study, we noticed that bridge exercise in a prone position is desirable for women who prefer wearing high heels as a back pain prevention exercise method.

Allogenic Myocytes and Mesenchymal Stem Cells Partially Improve Fatty Rotator Cuff Degeneration in a Rat Model.

PubMed

Güleçyüz, Mehmet F; Macha, Konstanze; Pietschmann, Matthias F; Ficklscherer, Andreas; Sievers, Birte; Roßbach, Björn P; Jansson, Volkmar; Müller, Peter E

2018-05-31

Rotator cuff (RC) tears result not only in functional impairment but also in RC muscle atrophy, muscle fattening and eventually to muscle fibrosis. We hypothesized that allogenic bone marrow derived mesenchymal stem cells (MSC) and myocytes can be utilized to improve the rotator cuff muscle fattening and increase the atrophied muscle mass in a rat model. The right supraspinatus (SSP) tendons of 105 inbred rats were detached and muscle fattening was provoked over 4 weeks; the left side remained untouched (control group). The animals (n = 25) of the output group were euthanized after 4 weeks for reference purposes. The SSP-tendon of one group (n = 16) was left unoperated to heal spontaneously. The SSP-tendons of the remaining 64 rats (4 groups with n = 16) were repaired with transosseous sutures. One group received a saline solution injection in the SSP muscle belly, two other groups received 5 × 10 6 allogenic myocytes and 5 × 10 6 allogenic MSC injections from donor rats, respectively, and one group received no additional treatment. After 4 weeks of healing, the supraspinatus muscle mass was compared quantitatively and histologically to all the treated groups and to the untreated contralateral side. In the end of the experiments at week 8, the myocyte and MCS treated groups showed a significantly higher muscle mass with 0.2322 g and 0.2257 g, respectively, in comparison to the output group (0.1911 g) at week 4 with p < 0.05. There was no statistical difference between the repaired, treated, or spontaneous healing groups at week 8. Supraspinatus muscle mass of all experimental groups of the right side was significantly lower compared to the untreated contralateral muscle mass. This defect model shows that the injection of allogenic mycocytes and MSC in fatty infiltrated SSP muscles is better than no treatment and can partially improve the SSP muscle belly fattening. Nevertheless, a full restoration of the degenerated and fattened rotator cuff muscle to its original condition is not possible using myocytes and MSC in this model.

Diversification of the muscle proteome through alternative splicing.

PubMed

Nakka, Kiran; Ghigna, Claudia; Gabellini, Davide; Dilworth, F Jeffrey

2018-03-06

Skeletal muscles express a highly specialized proteome that allows the metabolism of energy sources to mediate myofiber contraction. This muscle-specific proteome is partially derived through the muscle-specific transcription of a subset of genes. Surprisingly, RNA sequencing technologies have also revealed a significant role for muscle-specific alternative splicing in generating protein isoforms that give specialized function to the muscle proteome. In this review, we discuss the current knowledge with respect to the mechanisms that allow pre-mRNA transcripts to undergo muscle-specific alternative splicing while identifying some of the key trans-acting splicing factors essential to the process. The importance of specific splicing events to specialized muscle function is presented along with examples in which dysregulated splicing contributes to myopathies. Though there is now an appreciation that alternative splicing is a major contributor to proteome diversification, the emergence of improved "targeted" proteomic methodologies for detection of specific protein isoforms will soon allow us to better appreciate the extent to which alternative splicing modifies the activity of proteins (and their ability to interact with other proteins) in the skeletal muscle. In addition, we highlight a continued need to better explore the signaling pathways that contribute to the temporal control of trans-acting splicing factor activity to ensure specific protein isoforms are expressed in the proper cellular context. An understanding of the signal-dependent and signal-independent events driving muscle-specific alternative splicing has the potential to provide us with novel therapeutic strategies to treat different myopathies.

Effects of inspiratory muscle training on balance ability and abdominal muscle thickness in chronic stroke patients

PubMed Central

Oh, Dongha; Kim, Gayeong; Lee, Wanhee; Shin, Mary Myong Sook

2016-01-01

[Purpose] This study evaluated the effects of inspiratory muscle training on pulmonary function, deep abdominal muscle thickness, and balance ability in stroke patients. [Subjects] Twenty-three stroke patients were randomly allocated to an experimental (n = 11) or control group (n = 12). [Methods] The experimental group received inspiratory muscle training-based abdominal muscle strengthening with conventional physical therapy; the control group received standard abdominal muscle strengthening with conventional physical therapy. Treatment was conducted 20 minutes per day, 3 times per week for 6 weeks. Pulmonary function testing was performed using an electronic spirometer. Deep abdominal muscle thickness was measured by ultrasonography. Balance was measured using the Berg balance scale. [Results] Forced vital capacity, forced expiratory volume in 1 second, deep abdominal muscle thickness, and Berg balance scale scores were significantly improved in the experimental group than in the control group. [Conclusion] Abdominal muscle strengthening accompanied by inspiratory muscle training is recommended to improve pulmonary function in stroke patients, and may also be used as a practical adjunct to conventional physical therapy. PMID:26957739

Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon: differential effects of specific contraction types.

PubMed

Heinemeier, K M; Olesen, J L; Schjerling, P; Haddad, F; Langberg, H; Baldwin, K M; Kjaer, M

2007-02-01

In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types on regulation of these factors in muscle are still unclear, and in tendon the functions of myostatin, IGF-IEa, and MGF in relation to training are unknown. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric, or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve during general anesthesia. mRNA levels for myostatin, IGF-IEa, and MGF in muscle and Achilles' tendon were measured by real-time RT-PCR. Muscle myostatin mRNA decreased in response to all types of training (2- to 8-fold) (P < 0.05), but the effect of eccentric training was greater than concentric and isometric training (P < 0.05). In tendon, myostatin mRNA was detected, but no changes were seen after exercise. IGF-IEa and MGF increased in muscle (up to 15-fold) and tendon (up to 4-fold) in response to training (P < 0.01). In tendon no difference was seen between training types, but in muscle the effect of eccentric training was greater than concentric training for both IGF-IEa and MGF (P < 0.05), and for IGF-IEa isometric training had greater effect than concentric (P < 0.05). The results indicate a possible role for IGF-IEa and MGF in adaptation of tendon to training, and the combined changes in myostatin and IGF-IEa/MGF expression could explain the important effect of eccentric actions for muscle hypertrophy.

Effects of age and muscle action type on acute strength and power recovery following fatigue of the leg flexors.

PubMed

Thompson, Brennan J; Conchola, Eric C; Stock, Matt S

2015-12-01

Short-term strength and power recovery patterns following fatigue have received little research attention, particularly as they pertain to age-specific responses, and the leg flexors (i.e., hamstrings) muscle group. Thus, research is warranted addressing these issues because both age-related alterations in the neuromuscular system and mode of muscle action (e.g., eccentric, concentric, isometric) may differentially influence recovery responses from fatigue. The aim of this study was to investigate the strength and power recovery responses for eccentric, concentric, and isometric muscle actions of the leg flexors in young and older men following an isometric, intermittent fatigue-inducing protocol. Nineteen young (age = 25 ± 3 years) and nineteen older (71 ± 4) men performed maximal voluntary contractions (MVCs) for eccentric, concentric, and isometric muscle actions followed by a fatigue protocol of intermittent (0.6 duty cycle) isometric contractions of the leg flexors at 60% of isometric MVC. MVCs of each muscle action were performed at 0, 7, 15, and 30 min following fatigue. Peak torque (PT) and mean power values were calculated from the MVCs and the eccentric/concentric ratio (ECR) was derived. For PT and mean power, young men showed incomplete recovery at all time phases, whereas the older men had recovered by 7 min. Eccentric and isometric muscle actions showed incomplete recovery at all time phases, but concentric recovered by 7 min, independent of age. The ECR was depressed for up to 30 min following fatigue. More rapid and pronounced recovery in older men and concentric contractions may be related to physiological differences specific to aging and muscle action motor unit patterns. Individuals and clinicians may use these time course responses as a guide for recovery following activity-induced fatigue.

Greater understanding of normal hip physical function may guide clinicians in providing targeted rehabilitation programmes.

PubMed

Kemp, Joanne L; Schache, Anthony G; Makdissi, Michael; Sims, Kevin J; Crossley, Kay M

2013-07-01

This study investigated tests of hip muscle strength and functional performance. The specific objectives were to: (i) establish intra- and inter-rater reliability; (ii) compare differences between dominant and non-dominant limbs; (iii) compare agonist and antagonist muscle strength ratios; (iv) compare differences between genders; and (v) examine relationships between hip muscle strength, baseline measures and functional performance. Reliability study and cross-sectional analysis of hip strength and functional performance. In healthy adults aged 18-50years, normalised hip muscle peak torque and functional performance were evaluated to: (i) establish intra-rater and inter-rater reliability; (ii) analyse differences between limbs, between antagonistic muscle groups and genders; and (iii) associations between strength and functional performance. Excellent reliability (intra-rater ICC=0.77-0.96; inter-rater ICC=0.82-0.95) was observed. No difference existed between dominant and non-dominant limbs. Differences in strength existed between antagonistic pairs of muscles: hip abduction was greater than adduction (p<0.001) and hip ER was greater than IR (p<0.001). Men had greater ER strength (p=0.006) and hop for distance (p<0.001) than women. Strong associations were observed between measures of hip muscle strength (except hip flexion) and age, height, and functional performance. Deficits in hip muscle strength or functional performance may influence hip pain. In order to provide targeted rehabilitation programmes to address patient-specific impairments, and determine when individuals are ready to return to physical activity, clinicians are increasingly utilising tests of hip strength and functional performance. This study provides a battery of reliable, clinically applicable tests which can be used for these purposes. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Normal muscle oxygen consumption and fatigability in sickle cell patients despite reduced microvascular oxygenation and hemorheological abnormalities.

PubMed

Waltz, Xavier; Pichon, Aurélien; Lemonne, Nathalie; Mougenel, Danièle; Lalanne-Mistrih, Marie-Laure; Lamarre, Yann; Tarer, Vanessa; Tressières, Benoit; Etienne-Julan, Maryse; Hardy-Dessources, Marie-Dominique; Hue, Olivier; Connes, Philippe

2012-01-01

Although it has been hypothesized that muscle metabolism and fatigability could be impaired in sickle cell patients, no study has addressed this issue. We compared muscle metabolism and function (muscle microvascular oxygenation, microvascular blood flow, muscle oxygen consumption and muscle microvascular oxygenation variability, which reflects vasomotion activity, maximal muscle force and local muscle fatigability) and the hemorheological profile at rest between 16 healthy subjects (AA), 20 sickle cell-hemoglobin C disease (SC) patients and 16 sickle cell anemia (SS) patients. Muscle microvascular oxygenation was reduced in SS patients compared to the SC and AA groups and this reduction was not related to hemorhelogical abnormalities. No difference was observed between the three groups for oxygen consumption and vasomotion activity. Muscle microvascular blood flow was higher in SS patients compared to the AA group, and tended to be higher compared to the SC group. Multivariate analysis revealed that muscle oxygen consumption was independently associated with muscle microvascular blood flow in the two sickle cell groups (SC and SS). Finally, despite reduced muscle force in sickle cell patients, their local muscle fatigability was similar to that of the healthy subjects. Sickle cell patients have normal resting muscle oxygen consumption and fatigability despite hemorheological alterations and, for SS patients only, reduced muscle microvascular oxygenation and increased microvascular blood flow. Two alternative mechanisms can be proposed for SS patients: 1) the increased muscle microvascular blood flow is a way to compensate for the lower muscle microvascular oxygenation to maintain muscle oxygen consumption to normal values or 2) the reduced microvascular oxygenation coupled with a normal resting muscle oxygen consumption could indicate that there is slight hypoxia within the muscle which is not sufficient to limit mitochondrial respiration but increases muscle microvascular blood flow.

Individualised pelvic floor muscle training in women with pelvic organ prolapse (POPPY): a multicentre randomised controlled trial.

PubMed

Hagen, Suzanne; Stark, Diane; Glazener, Cathryn; Dickson, Sylvia; Barry, Sarah; Elders, Andrew; Frawley, Helena; Galea, Mary P; Logan, Janet; McDonald, Alison; McPherson, Gladys; Moore, Kate H; Norrie, John; Walker, Andrew; Wilson, Don

2014-03-01

Pelvic organ prolapse is common and is strongly associated with childbirth and increasing age. Women with prolapse are often advised to do pelvic floor muscle exercises, but evidence supporting the benefits of such exercises is scarce. We aimed to establish the effectiveness of one-to-one individualised pelvic floor muscle training for reducing prolapse symptoms. We did a parallel-group, multicentre, randomised controlled trial at 23 centres in the UK, one in New Zealand, and one in Australia, between June 22, 2007, and April 9, 2010. Female outpatients with newly-diagnosed, symptomatic stage I, II, or III prolapse were randomly assigned (1:1), by remote computer allocation with minimsation, to receive an individualised programme of pelvic floor muscle training or a prolapse lifestyle advice leaflet and no muscle training (control group). Outcome assessors, and investigators who were gynaecologists at trial sites, were masked to group allocation; the statistician was masked until after data analysis. Our primary endpoint was participants' self-report of prolapse symptoms at 12 months. Analysis was by intention-to-treat analysis. This trial is registered, number ISRCTN35911035. 447 eligible patients were randomised to the intervention group (n=225) or the control group (n=222). 377 (84%) participants completed follow-up for questionnaires at 6 months and 295 (66%) for questionnaires at 12 months. Women in the intervention group reported fewer prolapse symptoms (ie, a significantly greater reduction in the pelvic organ prolapse symptom score [POP-SS]) at 12 months than those in the control group (mean reduction in POP-SS from baseline 3.77 [SD 5.62] vs 2.09 [5.39]; adjusted difference 1.52, 95% CI 0.46-2.59; p=0.0053). Findings were robust to missing data. Eight adverse events (six vaginal symptoms, one case of back pain, and one case of abdominal pain) and one unexpected serious adverse event, all in women from the intervention group, were regarded as unrelated to the intervention or to participation in the study. One-to-one pelvic floor muscle training for prolapse is effective for improvement of prolapse symptoms. Long-term benefits should be investigated, as should the effects in specific subgroups. Chief Scientist Office of the Scottish Government Health and Social Care Directorates, New Zealand Lottery Board, and National Health and Medical Research Council (Australia). Copyright © 2014 Elsevier Ltd. All rights reserved.

[Effects of Reactive Jump Training in Handball Players Regarding Jump Height and Power Development in the Triceps Surae Muscle].

PubMed

Rensing, N; Westermann, A; Möller, D; von Piekartz, H

2015-12-01

Studies have shown changes in the technical and physical demands in modern handball. The game has increased considerably in speed, power and dynamics. Jump training has, therefore, become ever more important in the training of the athletes. These developments contribute to the fact that handball is now one of the most injury-prone types of sport, with the lower extremities being most frequently affected. Reactive jump training is not only used in training by now, but also increasingly in injury prevention. The aim of this study was to investigate the effectiveness of reactive jump training with handball players. 21 regional league handball players were randomly divided into an intervention group (n = 12) and a control group (n = 9). The intervention group completed a six-week reactive jump training programme while the control group went through a non-specific training programme. Jump height (squat and counter movement jump), isokinetic and isometric maximum power as well as muscle activity served as measuring parameters. A comparison of the intervention and control groups revealed that the reactive jump training led to significant improvements in jump height. The isometric and isokinetic maximum power measurements and the electromyographic activities of the triceps surae muscle demonstrated an improvement in the values within the intervention group. However, this improvement was not significant compared with the control group. Likewise both jumps correlated with the muscle activity of the soleus muscle as shown by electromyography. A moderate correlation was noticed between the isokinetic maximum power measurement and the electromyographic activity of the soleus and gastrocnemius medialis muscles. Furthermore, the correlations of the isometric and isokinetic maximum power meas-urements resulted in a strong correlation coefficient. This study revealed a significant increase in jump height after reactive jump training. There was no significant difference in power development between the two groups. However, we were able to demonstrate correlations which would make it seem reasonable and interesting to investigate the question more closely. An interesting field of research could be the question of the effectiveness of reactive jump training in the areas of rehabilitation and injury prevention. © Georg Thieme Verlag KG Stuttgart · New York.

Human skeletal muscle fibre contractile properties and proteomic profile: adaptations to 3 weeks of unilateral lower limb suspension and active recovery.

PubMed

Brocca, Lorenza; Longa, Emanuela; Cannavino, Jessica; Seynnes, Olivier; de Vito, Giuseppe; McPhee, Jamie; Narici, Marco; Pellegrino, Maria Antonietta; Bottinelli, Roberto

2015-12-15

It is generally assumed that muscle fibres go through atrophy following disuse with a loss of specific force and an increase in unloaded shortening velocity. However, the underlying mechanisms remain to be clarified. Most studies have focused on events taking place during the development of disuse, whereas the subsequent recovery phase, which is equally important, has received little attention. Our findings support the hypotheses that the specific force of muscle fibres decreased following unilateral lower limb suspension (ULLS) and returned to normal after 3 weeks of active recovery as a result of a loss and recovery of myosin and actin content. Furthermore, muscle fibres went through extensive qualitative changes in muscle protein pattern following ULLS, and these were reversed by active recovery. Resistance training was very effective in restoring both muscle mass and qualitative muscle changes, indicating that long-term ULLS did not prevent the positive effect of exercise on human muscle. Following disuse, muscle fibre function goes through adaptations such as a loss of specific force (PO /CSA) and an increase in unloaded shortening velocity, which could be a result of both quantitative changes (i.e. atrophy) and qualitative changes in protein pattern. The underlying mechanisms remain to be clarified. In addition, little is known about the recovery of muscle mass and strength following disuse. In the present study, we report an extensive dataset describing, in detail,the functional and protein content adaptations of skeletal muscle in response to both disuse and re-training. Eight young healthy subjects were subjected to 3 weeks of unilateral lower limb suspension (ULLS), a widely used human model of disuse skeletal muscle atrophy. Needle biopsies samples were taken from the vastus lateralis muscle Pre-ULLS, Post-ULLS and after 3 weeks of recovery during which heavy resistance training was performed. After disuse, cross-sectional area (CSA), PO /CSA and myosin concentration (MC) decreased in both type 1 and 2A skinned muscle fibres. After recovery, CSA and MC returned to levels comparable to those observed before disuse, whereas Po/CSA and unloaded shortening velocity reached a higher level. Myosin heavy chain isoform composition of muscle samples did not differ among the experimental groups. To study the mechanisms underlying such adaptations, a two-dimensional proteomic analysis was performed. ULLS induced a reduction of myofibrillar, metabolic (glycolytic and oxidative) and anti-oxidant defence system protein content. Resistance training was very effective in counteracting ULLS-induced alterations, indicating that long-term ULLS did not prevent the positive effect of exercise on human muscle. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

The effects of a multisensory dynamic balance training on the thickness of lower limb muscles in ultrasonography in children with spastic diplegic cerebral palsy.

PubMed

Nam, Seung-Min; Kim, Won-Hyo; Yun, Chang-Kyo

2017-04-01

[Purpose] This study aimed to investigate the effects of multisensory dynamic balance training on muscles thickness such as rectus femoris, anterior tibialis, medial gastrocnemius, lateral gastrocnemius in children with spastic diplegic cerebral palsy by using ultrasonography. [Subjects and Methods] Fifteen children diagnosed with spastic diplegic cerebral palsy were divided randomly into the balance training group and control group. The experimental group only received a multisensory dynamic balance training, while the control group performed general physiotherapy focused balance and muscle strengthening exercise based Neurodevelopmental treatment. Both groups had a therapy session for 30 minutes per day, three times a week for six weeks. The ultrasonographic muscle thickness were obtained in order to compare and analyze muscle thickness before and after in each group. [Result] The experimental group had significant increases in muscle thickness in the rectus femoris, tibialis anterior, medial gastrocnemius and lateral gastrocnemius muscles. The control group had significant increases in muscle thickness in the tibialis anterior. The test results of the rectus femoris, medial gastrocnemius and lateral gastrocnemius muscle thickness values between the groups showed significant differences. [Conclusion] In conclusion, a multisensory dynamic balance training can be recommended as a treatment method for patients with spastic diplegic cerebral palsy.

Superficial or deep implantation of motor nerve after denervation: an experimental study--superficial or deep implantation of motor nerve.

PubMed

Askar, Ibrahím; Sabuncuoglu, Bízden Tavíl

2002-01-01

Neurorraphy, conventional nerve grafting technique, and artificial nerve conduits are not enough for repair in severe injuries of peripheral nerves, especially when there is separation of motor nerve from muscle tissue. In these nerve injuries, reinnervation is indicated for neurotization. The distal end of a peripheral nerve is divided into fascicles and implanted into the aneural zone of target muscle tissue. It is not known how deeply fascicles should be implanted into muscle tissue. A comparative study of superficial and deep implantation of separated motor nerve into muscle tissue is presented in the gastrocnemius muscle of rabbits. In this experimental study, 30 white New Zealand rabbits were used and divided into 3 groups of 10 rabbits each. In the first group (controls, group I), only surgical exposure of the gastrocnemius muscle and motor nerve (tibial nerve) was done without any injury to nerves. In the superficial implantation group (group II), tibial nerves were separated and divided into their own fascicles. These fascicles were implanted superficially into the lateral head of gastrocnemius muscle-aneural zone. In the deep implantation group (group III), the tibial nerves were separated and divided into their own fascicles. These fascicles were implanted around the center of the muscle mass, into the lateral head of the gastrocnemius muscle-aneural zone. Six months later, histopathological changes and functional recovery of the gastrocnemius muscle were investigated. Both experimental groups had less muscular weight than in the control group. It was found that functional recovery was achieved in both experimental groups, and was better in the superficial implantation group than the deep implantation group. EMG recordings revealed that polyphasic and late potentials were frequently seen in both experimental groups. Degeneration and regeneration of myofibrils were observed in both experimental groups. New motor end-plates were formed in a scattered manner in both experimental groups. However, they were more dense in the superficial implantation group than the deep implantation group. It was concluded that superficial implantation has a more powerful contractile capacity than that of deep implantation. We believe that this might arise from the high activity of glycolytic enzymes in peripheral muscle fibers of gastrocnemius muscle, decrease in insufficient intramuscular guidance apparatus, and intramuscular microneuroma formation at the insufficient neuromuscular junction since the motor nerve had less route to muscle fibers. Copyright 2002 Wiley-Liss, Inc.

Comparison of flavor changes in cooked-refrigerated beef, pork and chicken meat patties.

PubMed

Rhee, K S; Anderson, L M; Sams, A R

2005-10-01

Beef and pork longissimus dorsi (LD) and semimembranosus (SM) and chicken breast (B) and thigh (T) muscles excised 24 h postmortem were ground by muscle/species group, formed into patties, pan-fried, refrigerated for 0, 3 or 6 days, and evaluated by a trained sensory panel for intensity of specific flavors. The rate of decline in species-specific natural meat flavor intensity and the rate of increase in "cardboard" (CBD) flavor intensity during the first half of the 6-day storage were fastest for beef, while such decline and increase during the entire storage period were slowest for chicken B. Overall trends of natural meat flavor and CBD intensity changes for chicken T appeared more like those for the red meats than chicken B. It was concluded that, while flavor deterioration can occur in cooked-stored meats from all the species, quantitative or the magnitude of differences between species would depend on muscle types and sensory terms/method used.

[Muscle strength of the cervical and lumbar spine in triathletes].

PubMed

Miltner, O; Siebert, C H; Müller-Rath, R; Kieffer, O

2010-12-01

The goal of this study was to analyse the muscle strength of the cervical and lumbar spine in ironman triathletes. The values were compared to the results obtained from a reference group. The test of the triathletes was carried out in an attempt to define a specific strength profile for these athletes. In this study, 20 long-distance triathletes (∅ 37.3 ± 7.6 years of age, ∅ 1.80 ± 0.1 m, ∅ 73.7 ± 6.0 kg) were evaluated with regard to their individual and sport-specific strengths of the cervical spine in 2 planes and of the trunk strengths in all 3 planes of motion. The trunk strength profile of the triathletes revealed good average results in the trunk extensors and the lateral flexors of the left trunk. The reference group is the data base of the company Proxomed®, Alzenau. It is based on results of 1045 untrained, symptom-free subjects of different ages. Lumbar extension: The extension of the force values shows no significant difference from the reference group. Lumbar flexion: The flexion tests show highly significantly lower force values (5.025 ± 0.81 N/kg vs. 6.67 ± 0.6 N/kg) than the reference group. Flexion/extension: In the sagittal plane values for the triathletes demonstrate an imbalance in muscle strength ratios. The abdominal muscles turn in relation to the back extensor muscles too weakly to be very significant. Lumbar rotation: The force values of the athletes in both directions (right: 6.185 ± 1.46 N/kg, left: 7.1 ± 1.57 N/kg vs. 10.05 ± 0.34 N/kg) are highly significantly (p ≤ 0.001) lower than the reference values. Ratio of rotation left/right: The ratio of left/right rotation in the reference group is set at 1 and thus shows an equally strong force level between the two sides. Lumbar lateral flexion: The triathletes do not show any significant differences between the force values. Compared to the reference group there is no significant difference to the left side flexion. In the lateral bending the athletes have significantly better values than the reference group. Ratio of lateral left/right: In the reference group the ratio is set at 1. For triathletes, it shows an average value of 0.93. This difference is not significant. Cervical extension: The extension of the force values (1.96 ± 0.59 N/kg vs. 3.03 ± 0.24 N/kg) shows a highly significant difference from the reference group. Cervical flexion: In flexion (1.3 ± 0.42 N/kg vs. 2.17 ± 0.22 N/kg) triathletes have highly significantly lower strength values than the reference group. Flexion/extension: The triathletes did not differ significantly from the reference values (0.69 ± 0.23 and 0.72 ± 0.08). Lateral cervical spine: In comparison to the reference group (left: 1.67 ± 0.48 N/kg, right: 1.55 ± 0.46 N/kg vs. 2.36 ± 0.15 N/kg) in which there is left/right lateral flexion, there is a highly significant difference. Right lateral flexion is weaker than the left. Ratio of lateral left/right: The triathletes have a significant imbalance in the lateral flexion of the cervical spine compared to the reference group (1.07 ± 0.15 to 1). In conclusion, in the triathlon there is a specific stress that is obviously not an adequate stimulus for the muscles of the cervical spine in order to achieve a balanced musculature and the athletes should be advised to practice a preventive approach with regard to these areas. © Georg Thieme Verlag KG Stuttgart · New York.

Bicuculline and strychnine suppress the mesencephalic locomotor region-induced inhibition of group III muscle afferent input to the dorsal horn.

PubMed

Degtyarenko, A M; Kaufman, M P

2003-01-01

We examined the effect of iontophoretic application of bicuculline methiodide and strychnine hydrochloride on the mesencephalic locomotor region (MLR)-induced inhibition of dorsal horn cells in paralyzed cats. The activity of 60 dorsal horn cells was recorded extracellularly in laminae I, II, V-VII of spinal segments L7-S1. Each of the cells was shown to receive group III muscle afferent input as demonstrated by their responses to electrical stimulation of the tibial nerve (mean latency and threshold of activation: 20.1+/-6.4 ms and 15.2+/-1.4 times motor threshold, respectively). Electrical stimulation of the MLR suppressed transmission in group III muscle afferent pathways to dorsal horn cells. Specifically the average number of impulses generated by the dorsal horn neurons in response to a single pulse applied to the tibial nerve was decreased by 78+/-2.8% (n=60) during the MLR stimulation. Iontophoretic application (10-50 nA) of bicuculline and strychnine (5-10 mM) suppressed the MLR-induced inhibition of transmission of group III afferent input to laminae I and II cells by 69+/-5% (n=10) and 29+/-7% (n=7), respectively. Likewise, bicuculline and strychnine suppressed the MLR-induced inhibition of transmission of group III afferent input to lamina V cells by 59+/-13% (n=14) and 39+/-11% (n=10), respectively. Our findings raise the possibility that GABA and glycine release onto dorsal horn neurons in the spinal cord may play an important role in the suppression by central motor command of thin fiber muscle afferent-reflex pathways.

Exposure to microgravity for 30 days onboard Bion M1 caused muscle atrophy and impaired regeneration in murine femoral Quadriceps

NASA Astrophysics Data System (ADS)

Radugina, E. A.; Almeida, E. A. C.; Blaber, E.; Poplinskaya, V. A.; Markitantova, Y. V.; Grigoryan, E. N.

2018-02-01

Mechanical unloading in microgravity during spaceflight is known to cause muscular atrophy, changes in muscle fiber composition, gene expression, and reduction in regenerative muscle growth. Although some limited data exists for long-term effects of microgravity in human muscle, these processes have mostly been studied in rodents for short periods of time. Here we report on how long-term (30-day long) mechanical unloading in microgravity affects murine muscles of the femoral Quadriceps group. To conduct these studies we used muscle tissue from 6 microgravity mice, in comparison to habitat (7), and vivarium (14) ground control mice from the NASA Biospecimen Sharing Program conducted in collaboration with the Institute for Biomedical Problems of the Russian Academy of Sciences, during the Russian Bion M1 biosatellite mission in 2013. Muscle histomorphology from microgravity specimens showed signs of extensive atrophy and regenerative hypoplasia relative to ground controls. Specifically, we observed a two-fold decrease in the number of myonuclei, compared to vivarium and ground controls, and central location of myonuclei, low density of myofibers in the tissue, and of myofibrils within a fiber, as well as fragmentation and swelling of myofibers. Despite obvious atrophy, muscle regeneration nevertheless appeared to have continued after 30 days in microgravity as evidenced by thin and short newly formed myofibers. Many of them, however, showed evidence of apoptotic cells and myofibril degradation, suggesting that long-term unloading in microgravity may affect late stages of myofiber differentiation. Ground asynchronous and vivarium control animals demonstrated normal, well-developed tissue structure with sufficient blood and nerve supply and evidence of regenerative formation of new myofibers free of apoptotic nuclei. Regenerative activity of satellite cells in muscles was observed both in microgravity and ground control groups, using Pax7 and Myogenin immunolocalization, as well as Myogenin expression analysis. In addition, we have detected positive nuclear immunolocalization of c-Jun and c-Myc proteins indicating their sensitivity to changes in gravitational loading in a given model. In summary, long-term spaceflight in microgravity caused significant atrophy and degeneration of the femoral Quadriceps muscle group, and it may interfere with muscle regenerative processes by inducing apoptosis in newly-formed myofibrils during their differentiation phase.

Reducing muscle injuries and reinjuries in one italian professional male soccer team

PubMed Central

Melegati, Gianluca; Tornese, Davide; Gevi, Maurizio; Trabattoni, Alessandro; Pozzi, Grazia; Schonhuber, Herbert; Volpi, Piero

2013-01-01

Summary Background. The incidence rate of muscle injuries and re-injuries in professional elite soccer players actually is very high and may interfere with the fate of a championship. Purpose. To investigate the effect of a two-tiered injury prevention programme on first injury and re-injury incidence in top level male soccer players. Study design Case Series Study. Muscle injuries and re-injuries sustained by a group of 36 soccer player of an italian elite soccer team have been collected during 2010–2011 season. These data have been compared with those collected during the previous season in the same elite soccer team. Results. A total of 64 injuries occurred, 36 (56%) of which during practice and 28 (44%) during matches. Muscle injuries accounted for 31.3% of the total (n=20), 70% (n=14) of which occurred during practice and 30% (n=6) during matches. Hamstring were the muscles most often injured (n=11) In all, 3 re-injuries occurred (15% of muscle injuries). No early re-injuries occurred. The incidence was 2.5 injuries/1000 hours and the burden was 37 days absence/1000 hours. Conclusions. Through the implementation of a group and personalized injury prevention program, we were able to reduce the total number of muscle injuries and days absent because of injury, in a team of elite soccer players, as compared to the previous season. Specifically, muscle injuries accounted for 31% of all injuries, as compared to 59% of all injuries sustained by the team during the previous season. The number of injuries/1000 hours of exposure was reduced by half (from 5.6 to 2.5) and the days absent/1000 hours fell from 106 to 37. PMID:24596697

Specificity of endurance, sprint and strength training on physical performance capacity in young athletes.

PubMed

Häkkinen, K; Mero, A; Kauhanen, H

1989-03-01

Three prebubescent athlete groups of endurance runners (E; n = 4), sprinters (S; n = 4) and weightlifters (WL; n = 4) and one control group (C; n = 6) as well as one junior but postpubescent weightlifter group (JWL; n = 6) volunteered as subjects in order to investigate specific effects of endurance, sprint and strength training on physical performance capacity during a 1 year follow-up period. The prepubescent E-group had higher (p less than 0.05) VO2 max (66.5 +/- 2.9 ml x kg1 x min-1) already at the beginning of the study than the other three groups. The prepubescent WL-group demonstrated greater (p less than 0.05) maximal muscular strength than the E-group and the WL-group increased its strength greatly by 21.4% (p less than 0.05) during the follow-up. No significant differences were observed in physical performance capacity between the prepubescent WL- and S-groups. Both groups demonstrated a slightly (ns.) better force-time curve recorded from the leg extensor muscles than the E-group and significant (p less than 0.05) increases occurred in these two groups in dynamic explosive performance during the follow-up. The postpubescent JWL-group demonstrated much greater (p less than 0.001) muscular mass and maximal strength than the prepubescent groups. No significant changes occurred in explosive types of performances in these athletes but significant (p less than 0.05) increase took place in the maximal neural activation and strength of the leg extensor muscles during the 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)

Could the peristaltic transition zone be caused by non-uniform esophageal muscle fiber architecture? A simulation study.

PubMed

Kou, W; Pandolfino, J E; Kahrilas, P J; Patankar, N A

2017-06-01

Based on a fully coupled computational model of esophageal transport, we analyzed how varied esophageal muscle fiber architecture and/or dual contraction waves (CWs) affect bolus transport. Specifically, we studied the luminal pressure profile in those cases to better understand possible origins of the peristaltic transition zone. Two groups of studies were conducted using a computational model. The first studied esophageal transport with circumferential-longitudinal fiber architecture, helical fiber architecture and various combinations of the two. In the second group, cases with dual CWs and varied muscle fiber architecture were simulated. Overall transport characteristics were examined and the space-time profiles of luminal pressure were plotted and compared. Helical muscle fiber architecture featured reduced circumferential wall stress, greater esophageal distensibility, and greater axial shortening. Non-uniform fiber architecture featured a peristaltic pressure trough between two high-pressure segments. The distal pressure segment showed greater amplitude than the proximal segment, consistent with experimental data. Dual CWs also featured a pressure trough between two high-pressure segments. However, the minimum pressure in the region of overlap was much lower, and the amplitudes of the two high-pressure segments were similar. The efficacy of esophageal transport is greatly affected by muscle fiber architecture. The peristaltic transition zone may be attributable to non-uniform architecture of muscle fibers along the length of the esophagus and/or dual CWs. The difference in amplitude between the proximal and distal pressure segments may be attributable to non-uniform muscle fiber architecture. © 2017 John Wiley & Sons Ltd.

Effects of endurance training in the leopard shark, Triakis semifasciata.

PubMed

Gruber, S J; Dickson, K A

1997-01-01

This study is the first to examine the effects of endurance training in an elasmobranch fish. Twenty-four leopard sharks (Triakis semifasciata) were divided randomly into three groups. Eight sharks were killed immediately, eight were forced to swim continuously for 6 wk against a current of 35 cm s-1 (60%-65% of maximal sustainable swimming speed), and eight were held for 6 wk in a tank without induced current. There were no changes due to training in maximal sustainable speed, oxygen consumption rates, percentage of the myotome composed of red and white muscle fibers, blood oxygen-carrying capacity, liver mass, liver lipid, glycogen, and protein concentrations, white muscle protein content, heart ventricle mass, or the specific activities of the enzymes citrate synthase, pyruvate kinase, and lactate dehydrogenase in the heart ventricle. In red myotomal muscle, citrate synthase activity increased 17% as a result of training, but there was no change in muscle fiber diameter. The greatest effects occurred in white myotomal muscle, in which a 34% increase in fiber diameter and a 36% increase in the activities of citrate synthase and lactate dehydrogenase occurred as a result of training. The conditioned fish also had significantly higher growth rates. The observed effects within the myotomal muscle may reflect the higher growth rates of the trained leopard sharks, or they may be a specific response to the increased energetic demands of the training activity, indicating characteristics that limit swimming performance in leopard sharks.

The influence of fat infiltration of back extensor muscles on osteoporotic vertebral fractures.

PubMed

So, Kwang-Young; Kim, Dae-Hee; Choi, Dong-Hyuk; Kim, Choong-Young; Kim, Jeong-Seok; Choi, Yong-Soo

2013-12-01

Retrospective study. To investigate the influence of fat infiltration at low back extensor muscles on osteoporotic vertebral fracture. In persons with stronger back muscles, the risk of osteoporotic vertebral fractures will likely be lower than in those persons with weaker back muscles. However, the degree of influence of fat infiltration of the back extensor muscle on osteoporotic vertebral fracture remains controversial. Two hundred and thirty-seven patients who had undergone lumbar spine magnetic resonance imaging and bone mineral density (BMD) were enrolled in this study. The amount of low back extensor muscle was determined using the pseudocoloring technique on an axial view of the L3 level. The patients were divided into two groups: osteoporotic vertebral fracture group (group A) and non-fracture group (group B). The amount of low back extensor muscle is compared with BMD, degenerative change of disc, osteophyte grade of facet joint and promontory angle to reveal the association between these factors. A negative correlation is found between age and the amount of low back extensor muscle (p=0.001). The amount of low back extensor muscle in group A and group B was 60.3%±14.5% and 64.2%±9.3% respectively, thus showing a significantly smaller amount of low back extensor muscle in the osteoporotic vertebral fracture group (p=0.015). Fat infiltration of low back extensor muscle was increased in osteoporotic vertebral fracture patients. Therefore, fat infiltration of low back extensor muscle in an elderly person may be a risk factor of osteoporotic vertebral fracture.

Dietary supplementation with a specific combination of high protein, leucine, and fish oil improves muscle function and daily activity in tumour-bearing cachectic mice

PubMed Central

van Norren, K; Kegler, D; Argilés, J M; Luiking, Y; Gorselink, M; Laviano, A; Arts, K; Faber, J; Jansen, H; van der Beek, E M; van Helvoort, A

2009-01-01

Cancer cachexia is characterised by metabolic alterations leading to loss of adipose tissue and lean body mass and directly compromises physical performance and the quality of life of cancer patients. In a murine cancer cachectic model, the effects of dietary supplementation with a specific combination of high protein, leucine and fish oil on weight loss, muscle function and physical activity were investigated. Male CD2F1 mice, 6–7 weeks old, were divided into body weight-matched groups: (1) control, (2) tumour-bearing, and (3) tumour-bearing receiving experimental diets. Tumours were induced by s.c. inoculation with murine colon adenocarcinoma (C26) cells. Food intake, body mass, tumour size and 24 h-activity were monitored. Then, 20 days after tumour/vehicle inoculation, the animals were killed and muscle function was tested ex vivo. Tumour-bearing mice showed reduced carcass, muscle and fat mass compared with controls. EDL muscle performance and total daily activity were impaired in the tumour-bearing mice. Addition of single nutrients resulted in no or modest effects. However, supplementation of the diet with the all-in combination of high protein, leucine and fish oil significantly reduced loss of carcass, muscle and fat mass (loss in mass 45, 52 and 65% of TB-con, respectively (P<0.02)) and improved muscle performance (loss of max force reduced to 55–64% of TB-con (P<0.05)). Moreover, total daily activity normalised after intervention with the specific nutritional combination (50% of the reduction in activity of TB-con (P<0.05)). In conclusion, a nutritional combination of high protein, leucine and fish oil reduced cachectic symptoms and improved functional performance in cancer cachectic mice. Comparison of the nutritional combination with its individual modules revealed additive effects of the single components provided. PMID:19259092

Statins Affect Skeletal Muscle Performance: Evidence for Disturbances in Energy Metabolism.

PubMed

Allard, Neeltje A E; Schirris, Tom J J; Verheggen, Rebecca J; Russel, Frans G M; Rodenburg, Richard J; Smeitink, Jan A M; Thompson, Paul D; Hopman, Maria T E; Timmers, Silvie

2018-01-01

Statin myopathy is linked to disturbances in mitochondrial function and exercise intolerance. To determine whether differences exist in exercise performance, muscle function, and muscle mitochondrial oxidative capacity and content between symptomatic and asymptomatic statin users, and control subjects. Cross-sectional study. Department of Physiology, Radboud University Medical Center. Long-term symptomatic and asymptomatic statin users, and control subjects (n = 10 per group). Maximal incremental cycling tests, involuntary electrically stimulated isometric quadriceps-muscle contractions, and biopsy of vastus lateralis muscle. Maximal exercise capacity, substrate use during exercise, muscle function, and mitochondrial energy metabolism. Peak oxygen uptake, maximal work load, and ventilatory efficiency were comparable between groups, but both statin groups had a depressed anaerobic threshold compared with the control group (P = 0.01). Muscle relaxation time was prolonged in both statin groups compared with the control group and rate of maximal force rise was decreased (Ptime×group < 0.001 for both measures). Mitochondrial activity of complexes II and IV was lower in symptomatic statin users than control subjects and tended to be lower for complex (C) III (CII: P = 0.03; CIII: P = 0.05; CIV: P = 0.04). Mitochondrial content tended to be lower in both statin groups than in control subjects. Statin use attenuated substrate use during maximal exercise performance, induced muscle fatigue during repeated muscle contractions, and decreased muscle mitochondrial oxidative capacity. This suggests disturbances in mitochondrial oxidative capacity occur with statin use even in patients without statin-induced muscle complaints. Copyright © 2017 Endocrine Society

Effects of transforming growth factor-β1 treatment on muscle regeneration and adipogenesis in glycerol-injured muscle.

PubMed

Mahdy, Mohamed A A; Warita, Katsuhiko; Hosaka, Yoshinao Z

2017-11-01

Transforming growth factor (TGF)-β1 is associated with fibrosis in many organs. Recent studies demonstrated that delivery of TGF-β1 into chemically injured muscle enhances fibrosis. In this study, we investigated the effects of exogenous TGF-β1 on muscle regeneration and adipogenesis in glycerol-injured muscle of normal mice. Tibialis anterior (TA) muscles were injured by glycerol injection. TGF-β1 was either co-injected with glycerol, as an 'early treatment' group, or injected at day 4 after glycerol, as a 'late treatment' group and the TA muscles were collected at day 7 after initial injury. Myotube density was significantly lower in the early treatment group than in the glycerol-injured group (without TGF-β1 treatment). Moreover, the Oil red O-positive area was significantly smaller in the early treatment group than in the late treatment group and glycerol-injured group. Furthermore, TGF-β1 treatment increased endomysial fibrosis and induced immunostaining of α-smooth muscle actin. The greater inhibitory effects of early TGF-β1 treatment than that of late TGF-β1 treatment during regeneration in glycerol-injured muscle suggest a more potent effect of TGF-β1 on the initial stage of muscle regeneration and adipogenesis. Combination of TGF-β1 with glycerol might be an alternative to enhance muscle fibrosis for future studies. © 2017 Japanese Society of Animal Science.

Brillouin spectroscopy reveals changes in muscular viscoelasticity in Drosophila POMT mutants

NASA Astrophysics Data System (ADS)

Meng, Zhaokai; Baker, Ryan; Panin, Vladislav M.; Yakovlev, Vladislav V.

2015-03-01

Muscular dystrophy (MD) is a group of muscle diseases that induce weakness in skeletal muscle and cause progressive muscle degeneration. The muscular mechanical properties (i.e., viscoelasticity), however, have not been thoroughly examined before and after MD. On the other hand, Brillouin spectroscopy (BS) provides a non-invasive approach to probing the local sound speed within a small volume. Moreover, recent advances in background-free Brillouin spectroscopy enable investigators to imaging not only transparent samples, but also turbid ones. In this study, we investigated the mechanical properties of muscles while employing Drosophila model of dystroglycanopathies, human congenital muscular dystrophies resulting from abnormal glycosylation of alphadystroglycan. Specifically, we analyzed larval abdominal muscles of Drosophila with mutations in protein Omannosyltransferase (POMT) genes. As a comparison, we have also examined muscular tissues dissected from wildtype Drosophila. The Brillouin spectra were obtained by a background free VIPA (virtually imaged phased array) spectrometer described in the previous report. As a reference, the Raman spectra were also acquired for each test. Our current results indicated that POMT defects cause changes in muscle elasticity, which suggests that muscular dystrophy conditions may be also associated with abnormalities in muscle elastic properties.

Muscle Mass Depletion Associated with Poor Outcome of Sepsis in the Emergency Department.

PubMed

Lee, YoonJe; Park, Hyun Kyung; Kim, Won Young; Kim, Myung Chun; Jung, Woong; Ko, Byuk Sung

2018-05-08

Muscle mass depletion has been suggested to predict morbidity and mortality in various diseases. However, it is not well known whether muscle mass depletion is associated with poor outcome in sepsis. We hypothesized that muscle mass depletion is associated with poor outcome in sepsis. Retrospective observational study was conducted in an emergency department during a 9-year period. Medical records of 627 patients with sepsis were reviewed. We divided the patients into 2 groups according to 28-day mortality and compared the presence of muscle mass depletion assessed by the cross-sectional area of the psoas muscle at the level of the third lumbar vertebra on abdomen CT scans. Univariate and multivariate logistic regression analyses were conducted to examine the association of scarcopenia on the outcome of sepsis. A total of 274 patients with sepsis were finally included in the study: 45 (16.4%) did not survive on 28 days and 77 patients (28.1%) were identified as having muscle mass depletion. The presence of muscle mass depletion was independently associated with 28-day mortality on multivariate logistic analysis (OR 2.79; 95% CI 1.35-5.74, p = 0.01). Muscle mass depletion evaluated by CT scan was associated with poor outcome of sepsis patients. Further studies on the appropriateness of specific treatment for muscle mass depletion with sepsis are needed. © 2018 S. Karger AG, Basel.

Molecular and biological pathways of skeletal muscle dysfunction in chronic obstructive pulmonary disease

PubMed Central

Gea, Joaquim

2016-01-01

Chronic obstructive pulmonary disease (COPD) will be a major leading cause of death worldwide in the near future. Weakness and atrophy of the quadriceps are associated with a significantly poorer prognosis and increased mortality in COPD. Despite that skeletal muscle dysfunction may affect both respiratory and limb muscle groups in COPD, the latter are frequently more severely affected. Therefore, muscle dysfunction in COPD is a common systemic manifestation that should be evaluated on routine basis in clinical settings. In the present review, several aspects of COPD muscle dysfunction are being reviewed, with special emphasis on the underlying biological mechanisms. Figures on the prevalence of COPD muscle dysfunction and the most relevant etiologic contributors are also provided. Despite that ongoing research will shed light into the contribution of additional mechanisms to COPD muscle dysfunction, current knowledge points toward the involvement of a wide spectrum of cellular and molecular events that are differentially expressed in respiratory and limb muscles. Such mechanisms are thoroughly described in the article. The contribution of epigenetic events on COPD muscle dysfunction is also reviewed. We conclude that in view of the latest discoveries, from now, on new avenues of research should be designed to specifically target cellular mechanisms and pathways that impair muscle mass and function in COPD using pharmacological strategies and/or exercise training modalities. PMID:27056059

Effect of mirror use on lower extremity muscle strength of patients with chronic stroke.

PubMed

Kim, Myoung-Kwon; Choe, Yu-Won; Shin, Young-Jun; Peng, Cheng; Choi, Eun-Hong

2018-02-01

[Purpose] This study examines the effect on muscle strength of lower extremity muscle strength exercise while using a mirror on the non-paretic side in patients with chronic stroke. [Subjects and Methods] Subjects were randomly assigned to a non-mirror lower extremity exercise group (n=10), a mirror lower extremity exercise group (n=10), or a mirror lower extremity muscle strength exercise group (n=10). Subjects were asked to do the exercise assigned to their group (5 sets 30 times a day, 5 times weekly for 4 weeks) with general physical therapy in the hospital. Muscle strength in the knee extensor and flexor of paretic and non-paretic side were measured using electrical muscle testing device before and after the intervention. [Results] Muscle strength significantly increased within each group after intervention. No significant differences were found among the three groups. [Conclusion] This study showed that the lower extremity muscle strength exercise of the non-paretic side using a mirror has a positive effect on muscle strength in patient with chronic stroke.

Effect of aqua exercise on recovery of lower limb muscles after downhill running.

PubMed

Takahashi, Junichiro; Ishihara, Keiji; Aoki, Junichiro

2006-08-01

The aim of the present study was to examine how the recovery of physiological functioning of the leg muscles after high-intensity eccentric exercise such as downhill running could be promoted by aqua exercise for a period until the damaged muscle had recovered almost completely. Ten male long-distance runners were divided equally into an aqua exercise group and a control group. From the first day (Day 0) to the fourth day (Day 3), the participants completed a questionnaire on muscle soreness, and serum creatine kinase activity, muscle power, flexibility, whole-body reaction time and muscle stiffness were measured. After measurements on Day 0, the participants performed downhill running (three 5 min runs with a 5 min rest interval at -10%, 335.7 +/- 6.1 m . min-1). The aqua exercise group performed walking, jogging and jumping in water on three successive days following the downhill running on Day 0 for 30 min each day. Muscle power was reduced on Day 1 in the control group (P < 0.05). Muscle soreness in the calf on Day 3 was greater in the control group than that in the aqua exercise group (P < 0.05). In the aqua exercise group, muscle stiffness in the calf was less than that in the control group over 4 days (time main effect: P < 0.05; group x time interaction: P < 0.05). We conclude that aqua exercise promoted physiological functioning of the muscles in the legs after high-intensity downhill running for a period until the damaged muscles had recovered almost completely.

Effect of pelvic floor muscle exercises in the treatment of urinary incontinence during pregnancy and the postpartum period.

PubMed

Dinc, Ayten; Kizilkaya Beji, Nezihe; Yalcin, Onay

2009-10-01

The aim of this study was to determine the effectiveness of pelvic floor muscle exercises on urinary incontinence during pregnancy and the postpartum period. The study was carried out on 80 pregnant women (study group, 40 subjects; control group, 40 subjects).The study group was trained by the researcher on how to do the pelvic floor muscle exercises. Both groups were evaluated for pelvic floor muscle strength and urinary complaints in their 36th to 38th week of pregnancy and postpartum sixth to eighth week. The study group had a significant decrease in urinary incontinence episodes during pregnancy and in the postpartum period, and their pelvic floor muscle strength increased to a larger extent. Control group had an increase in the postpartum muscle strength and decrease in the incontinence episodes in the postpartum period. Pelvic floor muscle exercises are quite effective in the augmentation of the pelvic floor muscle strength and consequently in the treatment of urinary incontinence.

Influence of nutrient intake on antioxidant capacity, muscle damage and white blood cell count in female soccer players

PubMed Central

2012-01-01

Background Soccer is a form of exercise that induces inflammatory response, as well as an increase in free radicals potentially leading to muscle injury. Balanced nutritional intake provides important antioxidant vitamins, including vitamins A, C and E, which may assist in preventing exercise-related muscle damage. The purpose of the present study was to determine the effect of macro/micronutrient intake on markers of oxidative stress, muscle damage, inflammatory and immune response in female soccer players. Methods Twenty-eight female players belonging to two soccer teams of the same professional soccer club participated in this study after being informed about the aims and procedures and after delivering written consent. Each team completed an 8-day dietary record and played one competition match the same week. Participants were divided into two groups: the REC group (who complied with recommended intakes) and the NO-REC group (who were not compliant). Laboratory blood tests were carried out to determine hematological, electrolytic and hormonal variables, as well as to monitor markers of cell damage and oxidative stress. Blood samples were obtained 24 h before, immediately after and 18 h after official soccer matches. Student t-test or Mann–Whitney U-test was used to compare both groups throughout the match. Results At rest, we observed that the REC group had higher levels of total antioxidant status (TAS), glutathione peroxidase (GPx), and lower levels of creatine kinase (CK) and lactate dehydrogenase (LDH) in comparison to the NO-REC group. Immediately after the match, levels of TAS, GPx, superoxide dismutase (SOD), LDH and % lymphocytes were higher and the % of neutrophils were lower in the REC group compared to the NO-REC group. These differences were also maintained 18 h post-match, only for TAS and GPx. Conclusions Our data reveal an association between nutritional intake and muscle damage, oxidative stress, immunity and inflammation markers. The benefit of the intake of specific nutrients may contribute to preventing the undesirable physiological effects provoked by soccer matches. PMID:22812729

Electrophysiology of Muscle Fatigue in Cardiopulmonary Resuscitation on Manikin Model.

PubMed

Cobo-Vázquez, Carlos; De Blas, Gemma; García-Canas, Pablo; Del Carmen Gasco-García, María

2018-01-01

Cardiopulmonary resuscitation requires the provider to adopt positions that could be dangerous for his or her spine, specifically affecting the muscles and ligaments in the lumbar zone and the scapular spinal muscles. Increased fatigue caused by muscular activity during the resuscitation could produce a loss of quality and efficacy, resulting in compromising resuscitation. The aim of this study was to evaluate the maximum time a rescuer can perform uninterrupted chest compressions correctly without muscle fatigue. This pilot study was performed at Universidad Complutense de Madrid (Spain) with the population recruited following CONSORT 2010 guidelines. From the 25 volunteers, a total of 14 students were excluded because of kyphoscoliosis (4), lumbar muscle pain (1), anti-inflammatory treatment (3), or not reaching 80% of effective chest compressions during the test (6). Muscle activity at the high spinal and lumbar (L5) muscles was assessed using electromyography while students performed continuous chest compressions on a ResusciAnne manikin. The data from force exerted were analyzed according to side and muscle groups using Student's t test for paired samples. The influence of time, muscle group, and side was analyzed by multivariate analyses ( p ≤ .05). At 2 minutes, high spinal muscle activity (right: 50.82 ± 9.95; left: 57.27 ± 20.85 μV/ms) reached the highest values. Activity decreased at 5 and 15 minutes. At 2 minutes, L5 activity (right: 45.82 ± 9.09; left: 48.91 ± 10.02 μV/ms) reached the highest values. After 5 minutes and at 15 minutes, activity decreased. Fatigue occurred bilaterally and time was the most important factor. Fatigue began at 2 minutes. Rescuers exert muscular countervailing forces in order to maintain effective compressions. This imbalance of forces could determine the onset of poor posture, musculoskeletal pain, and long-term injuries in the rescuer.

The significance of alteration 2-[fluorine-18]fluoro-2-deoxy-(D)-glucose uptake in the liver and skeletal muscles of patients with hyperthyroidism.

PubMed

Chen, Yen-Kung; Chen, Yen-Ling; Tsui, Chih-Cheng; Wang, Su-Chen; Cheng, Ru-Hwa

2013-10-01

Hyperthyroidism leads to an enhanced demand for glucose. The hypothesis of the study is that 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) can demonstrate the alteration of systemic glucose metabolism in hyperthyroidism patients by measuring the FDG standard uptake value (SUV) in liver and skeletal muscle. Forty-eight active hyperthyroidism patients and 30 control participants were recruited for the study. The intensity of FDG uptake in the liver and thigh muscles was graded subjectively, comprising three groups: group I, higher FDG uptake in the liver; group II, equal FDG uptake in the liver and muscles; and group III, higher FDG uptake in the muscles. Ten subjects with FDG PET scans at hyperthyroid and euthyroid status were analyzed. Serum levels of thyroxine (T4) and triiodothyronine (T3) correlated to the SUVs of the liver and muscles. Forty-one patients (41/48, 85.4%) showed symmetrically increased FDG uptake in the muscles (22 in group I, 9 in group II, and 17 in group III). Group I patients were significantly older than group II (P = .02) and group III (P = .001) patients. The correlation coefficient between the serum T3, T4, and SUV levels in the muscles was significant (r = 0.47-0.77, P < .01), particularly in liver and muscle FDG uptake between hyperthyroid and euthyroid states. In the 30 control subjects, there was normal physiological FDG uptake in the liver and muscles. In PET scans showing a pattern of decreased liver and increased skeletal muscle FDG uptake in hyperthyroidism patients, this change of FDG distribution is correspondence to the severity of hyperthyroidism status. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Mindfulness in the Maintenance of Cognitive Capacities in Alzheimer's Disease: A Randomized Clinical Trial.

PubMed

Quintana-Hernández, Domingo J; Miró-Barrachina, María T; Ibáñez-Fernández, Ignacio J; Pino, Angelo Santana-Del; Quintana-Montesdeoca, María P; Rodríguez-de Vera, Bienvenida; Morales-Casanova, David; Pérez-Vieitez, María Del Carmen; Rodríguez-García, Javier; Bravo-Caraduje, Noelia

2016-01-01

The Canary Islands longitudinal study on non-pharmacological treatments showed the overall effectiveness of mindfulness in Alzheimer's disease (AD). However, no specific data on the maintenance of cognitive capacities were presented. To determine whether the practice of mindfulness modifies the course of cognitive impairment in AD. Longitudinal, non-inferiority and equivalence, randomized clinical trial, repeated-measures design, with three experimental groups and one control group. Patients with AD who voluntarily attended the Lidia García Foundation (n = 502). Only those who were treated with donepezil and MMSE ≥18 were included (n = 120). Over a two-year period, each group carried out three weekly sessions of stimulation based on mindfulness, cognitive stimulation therapy, and progressive muscle relaxation. Cognitive assessment CAMDEX-R (MMSE and CAMCOG). Repeated-measures ANOVA (p <  0.05) and the effect size Cohen's d were performed. The mindfulness group showed significant scores compared with the control and muscle relaxation groups (p <  0.05), while mindfulness and cognitive stimulation therapy were equivalent (p≥0.05). Group cognitive stimulation evolved better than the control (p <  0.05) group but not better than the muscle relaxation group (p≥0.05). The effect size compared over two years was large for the mindfulness group (p≥0.80), moderate for the relaxation group (p≥0.50), and low for the cognitive stimulation group (p≥0.20). The practice of mindfulness maintained cognitive function over a period of two years. This longitudinal study suggests that mindfulness can be used as a non-pharmacological treatment to slow cognitive impairment in AD.

Loss-of-function mutations in SCN4A cause severe foetal hypokinesia or ‘classical’ congenital myopathy

PubMed Central

Zaharieva, Irina T.; Thor, Michael G.; Oates, Emily C.; van Karnebeek, Clara; Hendson, Glenda; Blom, Eveline; Witting, Nanna; Rasmussen, Magnhild; Gabbett, Michael T.; Ravenscroft, Gianina; Sframeli, Maria; Suetterlin, Karen; Sarkozy, Anna; D’Argenzio, Luigi; Hartley, Louise; Matthews, Emma; Pitt, Matthew; Vissing, John; Ballegaard, Martin; Krarup, Christian; Slørdahl, Andreas; Halvorsen, Hanne; Ye, Xin Cynthia; Zhang, Lin-Hua; Løkken, Nicoline; Werlauff, Ulla; Abdelsayed, Mena; Davis, Mark R.; Feng, Lucy; Phadke, Rahul; Sewry, Caroline A.; Morgan, Jennifer E.; Laing, Nigel G.; Vallance, Hilary; Ruben, Peter; Hanna, Michael G.; Lewis, Suzanne; Kamsteeg, Erik-Jan; Männikkö, Roope

2016-01-01

Abstract See Cannon (doi: 10.1093/brain/awv400 ) for a scientific commentary on this article. Congenital myopathies are a clinically and genetically heterogeneous group of muscle disorders characterized by congenital or early-onset hypotonia and muscle weakness, and specific pathological features on muscle biopsy. The phenotype ranges from foetal akinesia resulting in in utero or neonatal mortality, to milder disorders that are not life-limiting. Over the past decade, more than 20 new congenital myopathy genes have been identified. Most encode proteins involved in muscle contraction; however, mutations in ion channel-encoding genes are increasingly being recognized as a cause of this group of disorders. SCN4A encodes the α-subunit of the skeletal muscle voltage-gated sodium channel (Na v 1.4). This channel is essential for the generation and propagation of the muscle action potential crucial to muscle contraction. Dominant SCN4A gain-of-function mutations are a well-established cause of myotonia and periodic paralysis. Using whole exome sequencing, we identified homozygous or compound heterozygous SCN4A mutations in a cohort of 11 individuals from six unrelated kindreds with congenital myopathy. Affected members developed in utero - or neonatal-onset muscle weakness of variable severity. In seven cases, severe muscle weakness resulted in death during the third trimester or shortly after birth. The remaining four cases had marked congenital or neonatal-onset hypotonia and weakness associated with mild-to-moderate facial and neck weakness, significant neonatal-onset respiratory and swallowing difficulties and childhood-onset spinal deformities. All four surviving cohort members experienced clinical improvement in the first decade of life. Muscle biopsies showed myopathic features including fibre size variability, presence of fibrofatty tissue of varying severity, without specific structural abnormalities. Electrophysiology suggested a myopathic process, without myotonia. In vitro functional assessment in HEK293 cells of the impact of the identified SCN4A mutations showed loss-of-function of the mutant Na v 1.4 channels. All, apart from one, of the mutations either caused fully non-functional channels, or resulted in a reduced channel activity. Each of the affected cases carried at least one full loss-of-function mutation. In five out of six families, a second loss-of-function mutation was present on the trans allele. These functional results provide convincing evidence for the pathogenicity of the identified mutations and suggest that different degrees of loss-of-function in mutant Na v 1.4 channels are associated with attenuation of the skeletal muscle action potential amplitude to a level insufficient to support normal muscle function. The results demonstrate that recessive loss-of-function SCN4A mutations should be considered in patients with a congenital myopathy. PMID:26700687

Loss-of-function mutations in SCN4A cause severe foetal hypokinesia or 'classical' congenital myopathy.

PubMed

Zaharieva, Irina T; Thor, Michael G; Oates, Emily C; van Karnebeek, Clara; Hendson, Glenda; Blom, Eveline; Witting, Nanna; Rasmussen, Magnhild; Gabbett, Michael T; Ravenscroft, Gianina; Sframeli, Maria; Suetterlin, Karen; Sarkozy, Anna; D'Argenzio, Luigi; Hartley, Louise; Matthews, Emma; Pitt, Matthew; Vissing, John; Ballegaard, Martin; Krarup, Christian; Slørdahl, Andreas; Halvorsen, Hanne; Ye, Xin Cynthia; Zhang, Lin-Hua; Løkken, Nicoline; Werlauff, Ulla; Abdelsayed, Mena; Davis, Mark R; Feng, Lucy; Phadke, Rahul; Sewry, Caroline A; Morgan, Jennifer E; Laing, Nigel G; Vallance, Hilary; Ruben, Peter; Hanna, Michael G; Lewis, Suzanne; Kamsteeg, Erik-Jan; Männikkö, Roope; Muntoni, Francesco

2016-03-01

Congenital myopathies are a clinically and genetically heterogeneous group of muscle disorders characterized by congenital or early-onset hypotonia and muscle weakness, and specific pathological features on muscle biopsy. The phenotype ranges from foetal akinesia resulting in in utero or neonatal mortality, to milder disorders that are not life-limiting. Over the past decade, more than 20 new congenital myopathy genes have been identified. Most encode proteins involved in muscle contraction; however, mutations in ion channel-encoding genes are increasingly being recognized as a cause of this group of disorders. SCN4A encodes the α-subunit of the skeletal muscle voltage-gated sodium channel (Nav1.4). This channel is essential for the generation and propagation of the muscle action potential crucial to muscle contraction. Dominant SCN4A gain-of-function mutations are a well-established cause of myotonia and periodic paralysis. Using whole exome sequencing, we identified homozygous or compound heterozygous SCN4A mutations in a cohort of 11 individuals from six unrelated kindreds with congenital myopathy. Affected members developed in utero- or neonatal-onset muscle weakness of variable severity. In seven cases, severe muscle weakness resulted in death during the third trimester or shortly after birth. The remaining four cases had marked congenital or neonatal-onset hypotonia and weakness associated with mild-to-moderate facial and neck weakness, significant neonatal-onset respiratory and swallowing difficulties and childhood-onset spinal deformities. All four surviving cohort members experienced clinical improvement in the first decade of life. Muscle biopsies showed myopathic features including fibre size variability, presence of fibrofatty tissue of varying severity, without specific structural abnormalities. Electrophysiology suggested a myopathic process, without myotonia. In vitro functional assessment in HEK293 cells of the impact of the identified SCN4A mutations showed loss-of-function of the mutant Nav1.4 channels. All, apart from one, of the mutations either caused fully non-functional channels, or resulted in a reduced channel activity. Each of the affected cases carried at least one full loss-of-function mutation. In five out of six families, a second loss-of-function mutation was present on the trans allele. These functional results provide convincing evidence for the pathogenicity of the identified mutations and suggest that different degrees of loss-of-function in mutant Nav1.4 channels are associated with attenuation of the skeletal muscle action potential amplitude to a level insufficient to support normal muscle function. The results demonstrate that recessive loss-of-function SCN4A mutations should be considered in patients with a congenital myopathy. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain.

Physical examination, magnetic resonance image, and electrodiagnostic study in patients with lumbosacral disc herniation or spinal stenosis.

PubMed

Lee, Jung Hwan; Lee, Sang-Ho

2012-10-01

To compare the clinical implications of electro-diagnostic study with those of magnetic resonance imaging in patients with lumbosacral intervertebral herniated disc or spinal stenosis. Retrospective study of clinical data. Patients with lumbosacral intervertebral herniated disc or spinal stenosis, diagnosed by clinical assessment and magnetic resonance imaging (MRI), were selected. A total of 753 patients (437 with lumbosacral intervertebral herniated disc and 316 with spinal stenosis) were included in the study. Clinical data for electrodiagnostic study (EDX)and MRI were compared and the sensitivity and specificity of these studies were evaluated. Among all subjects, 267 had radiculopathy on EDX (EDX (+)) and 486 no radiculopathy (EDX(-)). Furthermore, 391 had root compression on MRI (MRI (+)) and 362 no root compression on MRI (MRI (-)). Patients with radioculopathy on EDX (+) showed a significantly higher visual analogue scale score for radiating pain and a higher Oswestry Disability Index than those with negative findings by EDX (-) in the total subjects group and the lumbosacral intervertebral herniated disc subgroup, and there was a trend toward higher Oswestry Disability Index in the spinal stenosis subgroup. Although patients with radioculopathy on root compression on MRI (+) also had a higher visual analogue scale for radiating pain than patients with negative findings by MRI (-) in the total subjects group and the lumbosacral intervertebral herniated disc subgroup, no significant difference was seen in the Oswestry Disability Index. EDX revealed a significant correlation with muscle weakness in the total subjects group and the lumbosacral intervertebral herniated disc subgroup, and trends toward muscle weakness in the spinal stenosis subgroup, whereas there was no such significant correlation for MRI findings in any group. Electrodiagnostic study had a higher specificity in terms of physical examination data than MRI, in spite of its lower sensitivity. Electrodiagnostic study was significantly more correlated with clinical data, especially leg muscle weakness and functional status, and showed a higher specificity than MRI in patients with lumbosacral intervertebral herniated disc or spinal stenosis.

Capacity of small groups of muscles to accomplish precision grasping tasks.

PubMed

Towles, Joseph D; Valero-Cuevas, Francisco J; Hentz, Vincent R

2013-01-01

An understanding of the capacity or ability of various muscle groups to generate endpoint forces that enable grasping tasks could provide a stronger biomechanical basis for the design of reconstructive surgery or rehabilitation for the treatment of the paralyzed or paretic hand. We quantified two-dimensional endpoint force distributions for every combination of the muscles of the index finger, in cadaveric specimens, to understand the capability of muscle groups to produce endpoint forces that accomplish three common types of grasps-tripod, tip and lateral pinch-characterized by a representative level of Coulomb friction. We found that muscle groups of 4 or fewer muscles were capable of generating endpoint forces that enabled performance of each of the grasping tasks examined. We also found that flexor muscles were crucial to accomplish tripod pinch; intrinsic muscles, tip pinch; and the dorsal interosseus muscle, lateral pinch. The results of this study provide a basis for decision making in the design of reconstructive surgeries and rehabilitation approaches that attempt to restore the ability to perform grasping tasks with small groups of muscles.

Correlation between quantitative whole-body muscle magnetic resonance imaging and clinical muscle weakness in Pompe disease.

PubMed

Horvath, Jeffrey J; Austin, Stephanie L; Case, Laura E; Greene, Karla B; Jones, Harrison N; Soher, Brian J; Kishnani, Priya S; Bashir, Mustafa R

2015-05-01

Previous examination of whole-body muscle involvement in Pompe disease has been limited to physical examination and/or qualitative magnetic resonance imaging (MRI). In this study we assess the feasibility of quantitative proton-density fat-fraction (PDFF) whole-body MRI in late-onset Pompe disease (LOPD) and compare the results with manual muscle testing. Seven LOPD patients and 11 disease-free controls underwent whole-body PDFF MRI. Quantitative MR muscle group assessments were compared with physical testing of muscle groups. The 95% upper limits of confidence intervals for muscle groups were 4.9-12.6% in controls and 6.8-76.4% in LOPD patients. LOPD patients showed severe and consistent tongue and axial muscle group involvement, with less marked involvement of peripheral musculature. MRI was more sensitive than physical examination for detection of abnormality in multiple muscle groups. This integrated, quantitative approach to muscle assessment provides more detailed data than physical examination and may have clinical utility for monitoring disease progression and treatment response. © 2014 Wiley Periodicals, Inc.

A pilot study to determine whether differences exist in histochemical properties between the trapezius and extensor carpi radialis brevis muscles in women with work-related myalgia.

PubMed

Green, Howard J; Ranney, Don; Burnett, Margaret; Galvin, Patti; Kyle, Natasha; Iqbal, Sobia; Lounsbury, David; Ouyang, Jing; Smith, Ian C; Stewart, Riley; Tick, Heather; Tupling, A Russell

2014-04-01

To investigate fibre-type abnormalities in women with work-related myalgia (WRM), tissue samples were extracted from their trapezius (TRAP) and the extensor carpi radialis brevis (ECRB) muscles and compared with healthy controls (CON). For the ECRB samples (CON, n = 6; WRM, n = 11), no differences (P > 0.05) were found between groups for any of the properties examined, namely fibre-type (I, IIA, IIX, IIAX) distribution, cross-sectional fibre area, capillary counts (CC), capillary to fibre area ratio, and succinic dehydrogenase activity. For the TRAP samples (CON, n = 6; WRM, n = 8), the only difference (P < 0.05) observed between groups was for CC (CON > WRM), which was not statistically significant (P > 0.05) when age was used a covariant. A comparison of the properties of these 2 muscles in the CON group indicated a higher (P < 0.05) and lower (P < 0.05) percentage of type I and type IIA fibres, respectively, in the TRAP as well as higher (P < 0.05) CC, which was not specific to fibre type. These preliminary results suggest that the properties employed to characterize fibre types do not differentiate CON from WRM for either the TRAP or ECRB. As a consequence, the role of inherent fibre-type differences between these muscles in the pathogenesis of WRM remains uncertain.

Core strengthening and synchronized swimming: TRX® suspension training in young female athletes.

PubMed

Tinto, Amalia; Campanella, Marta; Fasano, Milena

2017-06-01

Developing muscle strength and full body stability is essential for the efficient execution of technical moves in synchronized swimming. However, many swimmers find it difficult to control body stability while executing particular figures in water. We evaluated the effects of TRX® suspension training (2 sessions weekly for 6 months on core strength and core stability in young female. Twenty synchronized swimmers (Beginners A category, mean age 10±1 years) are divided in experimental group (EG; N.=10 athletes) and control group (CG; N.=10 athletes). EG received suspension training twice weekly (each session lasting about 15 min) as dryland exercises for 6 months in addition to routine training. CG completed routine training with conventional dryland exercises. Before (T1) and after (T2) completion of the study oblique and transversus abdominis muscle force was measured using a Stabilizer Pressure Biofeedback unit, in prone and supine positions, and isotonic muscle endurance was evaluated with the McGill Test. Non-parametric statistical analysis showed a significant increase (P<0.0001) in the majority of the parameters in the experimental group. The study results provide evidence for the benefit of integrating TRX® suspension training in dryland exercises for muscle strengthening in young athletes practicing synchronized swimming, and in general reiterates the importance of strengthening the core area to ensure stability and specific adaptations, improve the quality of the movement and prevent against injury.

Effects of Inspiratory Muscle Training and Calisthenics-and-Breathing Exercises in COPD With and Without Respiratory Muscle Weakness.

PubMed

Basso-Vanelli, Renata P; Di Lorenzo, Valéria A Pires; Labadessa, Ivana G; Regueiro, Eloisa M G; Jamami, Mauricio; Gomes, Evelim L F D; Costa, Dirceu

2016-01-01

Patients with COPD may experience respiratory muscle weakness. Two therapeutic approaches to the respiratory muscles are inspiratory muscle training and calisthenics-and-breathing exercises. The aims of the study are to compare the effects of inspiratory muscle training and calisthenics-and-breathing exercises associated with physical training in subjects with COPD as an additional benefit of strength and endurance of the inspiratory muscles, thoracoabdominal mobility, physical exercise capacity, and reduction in dyspnea on exertion. In addition, these gains were compared between subjects with and without respiratory muscle weakness. 25 subjects completed the study: 13 composed the inspiratory muscle training group, and 12 composed the calisthenics-and-breathing exercises group. Subjects were assessed before and after training by spirometry, measurements of respiratory muscle strength and test of inspiratory muscle endurance, thoracoabdominal excursion measurements, and the 6-min walk test. Moreover, scores for the Modified Medical Research Council dyspnea scale were reported. After intervention, there was a significant improvement in both groups of respiratory muscle strength and endurance, thoracoabdominal mobility, and walking distance in the 6-min walk test. Additionally, there was a decrease of dyspnea in the 6-min walk test peak. A difference was found between groups, with higher values of respiratory muscle strength and thoracoabdominal mobility and lower values of dyspnea in the 6-min walk test peak and the Modified Medical Research Council dyspnea scale in the inspiratory muscle training group. In the inspiratory muscle training group, subjects with respiratory muscle weakness had greater gains in inspiratory muscle strength and endurance. Both interventions increased exercise capacity and decreased dyspnea during physical effort. However, inspiratory muscle training was more effective in increasing inspiratory muscle strength and endurance, which could result in a decreased sensation of dyspnea. In addition, subjects with respiratory muscle weakness that performed inspiratory muscle training had higher gains in inspiratory muscle strength and endurance but not of dyspnea and submaximal exercise capacity. (ClinicalTrials.gov registration NCT01510041.). Copyright © 2016 by Daedalus Enterprises.

Sensitivity and specificity of eustachian tube function tests in adults.

PubMed

Doyle, William J; Swarts, J Douglas; Banks, Julianne; Casselbrant, Margaretha L; Mandel, Ellen M; Alper, Cuneyt M

2013-07-01

The study demonstrates the utility of eustachian tube (ET) function (ETF) test results for accurately assigning ears to disease state. To determine if ETF tests can identify ears with physician-diagnosed ET dysfunction (ETD) in a mixed population at high sensitivity and specificity and to define the interrelatedness of ETF test parameters. Through use of the forced-response, inflation-deflation, Valsalva, and sniffing tests, ETF was evaluated in 15 control ears of adult subjects after unilateral myringotomy (group 1) and in 23 ears of 19 adult subjects with ventilation tubes inserted for ETD (group 2). Data were analyzed using logistic regression including each parameter independently and then a step-down discriminant analysis including all ETF test parameters to predict group assignment. Factor analysis operating over all parameters was used to explore relatedness. ETF testing. ETF parameters for the forced response, inflation-deflation, Valsalva, and sniffing tests measured in 15 control ears of adult subjects after unilateral myringotomy (group 1) and in 23 ears of 19 adult subjects with ventilation tubes inserted for ETD (group 2). The discriminant analysis identified 4 ETF test parameters (Valsalva, ET opening pressure, dilatory efficiency, and percentage of positive pressure equilibrated) that together correctly assigned ears to group 2 at a sensitivity of 95% and a specificity of 83%. Individual parameters representing the efficiency of ET opening during swallowing showed moderately accurate assignments of ears to their respective groups. Three factors captured approximately 98% of the variance among parameters: the first had negative loadings of the ETF structural parameters; the second had positive loadings of the muscle-assisted ET opening parameters; and the third had negative loadings of the muscle-assisted ET opening parameters and positive loadings of the structural parameters. These results show that ETF tests can correctly assign individual ears to physician-diagnosed ETD with high sensitivity and specificity and that ETF test parameters can be grouped into structural-functional categories.

Low-intensity red and infrared lasers affect mRNA expression of DNA nucleotide excision repair in skin and muscle tissue.

PubMed

Sergio, Luiz Philippe S; Campos, Vera Maria A; Vicentini, Solange C; Mencalha, Andre Luiz; de Paoli, Flavia; Fonseca, Adenilson S

2016-04-01

Lasers emit light beams with specific characteristics, in which wavelength, frequency, power, fluence, and emission mode properties determine the photophysical, photochemical, and photobiological responses. Low-intensity lasers could induce free radical generation in biological tissues and cause alterations in macromolecules, such as DNA. Thus, the aim of this work was to evaluate excision repair cross-complementing group 1 (ERCC1) and excision repair cross-complementing group 2 (ERCC2) messenger RNA (mRNA) expression in biological tissues exposed to low-intensity lasers. Wistar rat (n = 28, 4 for each group) skin and muscle were exposed to low-intensity red (660 nm) and near-infrared (880 nm) lasers at different fluences (25, 50, and 100 J/cm(2)), and samples of these tissues were withdrawn for RNA extraction, cDNA synthesis, and gene expression evaluation by quantitative polymerase chain reaction. Laser exposure was in continuous wave and power of 100 mW. Data show that ERCC1 and ERCC2 mRNA expressions decrease in skin (p < 0.001) exposed to near-infrared laser, but increase in muscle tissue (p < 0.001). ERCC1 mRNA expression does not alter (p > 0.05), but ERCC2 mRNA expression decreases in skin (p < 0.001) and increases in muscle tissue (p < 0.001) exposed to red laser. Our results show that ERCC1 and ERCC2 mRNA expression is differently altered in skin and muscle tissue exposed to low-intensity lasers depending on wavelengths and fluences used in therapeutic protocols.

Effects on Hamstring Muscle Extensibility, Muscle Activity, and Balance of Different Stretching Techniques

PubMed Central

Lim, Kyoung-Il; Nam, Hyung-Chun; Jung, Kyoung-Sim

2014-01-01

[Purpose] The purpose of this study was to investigate the effects of two different stretching techniques on range of motion (ROM), muscle activation, and balance. [Subjects] For the present study, 48 adults with hamstring muscle tightness were recruited and randomly divided into three groups: a static stretching group (n=16), a PNF stretching group (n=16), a control group (n=16). [Methods] Both of the stretching techniques were applied to the hamstring once. Active knee extension angle, muscle activation during maximum voluntary isometric contraction (MVC), and static balance were measured before and after the application of each stretching technique. [Results] Both the static stretching and the PNF stretching groups showed significant increases in knee extension angle compared to the control group. However, there were no significant differences in muscle activation or balance between the groups. [Conclusion] Static stretching and PNF stretching techniques improved ROM without decrease in muscle activation, but neither of them exerted statistically significant effects on balance. PMID:24648633

Assessment of cross-sectional thickness and activity of masseter, anterior temporalis and orbicularis oris muscles in oral submucous fibrosis patients and healthy controls: an ultrasonography and electromyography study

PubMed Central

Bhowate, R R; Sharda, N

2014-01-01

Objectives: Oral submucous fibrosis (OSMF) is an insidious chronic disease that is associated with significant functional morbidity and an increased risk for malignancy. It initially affects the lamina propria of the oral mucosa, and, as the disease progresses, it involves the submucosa and deeper tissue, including muscles of the oral cavity, resulting in loss of fibroelasticity. OSMF is a pre-malignant condition mainly caused by areca nut chewing. The aim of this study was to find out the involvement of muscles of mastication and facial expression in patients with OSMF by assessing the cross-sectional thickness and activity of the masseter, anterior temporalis and orbicularis oris muscles by ultrasonography and electromyography and comparing with healthy controls and also to find out any correlation between the ultrasonographic cross-sectional thicknesses of the masseter, anterior temporalis and orbicularis oris muscles with electromyographic activity. Methods: 40 patients with OSMF were included in the study group, and the patients were divided into four groups on the basis of interincisal mouth opening, i.e. Group I (mouth opening >35 mm), Group II (mouth opening between 30 and 35 mm), Group III (mouth opening between 20 and 30 mm) and Group IV (mouth opening <20 mm). Ultrasonographic cross-sectional thickness and electromyographic activity (amplitude and duration) of the masseter, anterior temporalis and orbicualris oris muscles were recorded in patients with OSMF and 20 controls. Intergroup comparison of ultrasonographic cross-sectional thickness and activity (amplitude and duration) was done, and Pearson's correlation coefficient was applied to find out any relation between ultrasonographic and electromyographic findings. Results: Thickness and activity of the masseter muscle was significantly reduced in Group IV (mouth opening <20 mm) when compared with the control group. The anterior temporalis and orbicularis oris muscles remained unaffected. A positive correlation was observed between the thicknesses of the masseter muscle and the amplitude in Groups I, II and III; the anterior temporalis muscle in Group II and the control group; and the orbicularis oris muscle in Groups II, III and IV. Conclusions: It was concluded that, among the muscles studied, there was an early involvement of the masseter muscle in patients with OSMF compared with that of other muscles. PMID:24720604

Assessment of cross-sectional thickness and activity of masseter, anterior temporalis and orbicularis oris muscles in oral submucous fibrosis patients and healthy controls: an ultrasonography and electromyography study.

PubMed

Kant, P; Bhowate, R R; Sharda, N

2014-01-01

Oral submucous fibrosis (OSMF) is an insidious chronic disease that is associated with significant functional morbidity and an increased risk for malignancy. It initially affects the lamina propria of the oral mucosa, and, as the disease progresses, it involves the submucosa and deeper tissue, including muscles of the oral cavity, resulting in loss of fibroelasticity. OSMF is a pre-malignant condition mainly caused by areca nut chewing. The aim of this study was to find out the involvement of muscles of mastication and facial expression in patients with OSMF by assessing the cross-sectional thickness and activity of the masseter, anterior temporalis and orbicularis oris muscles by ultrasonography and electromyography and comparing with healthy controls and also to find out any correlation between the ultrasonographic cross-sectional thicknesses of the masseter, anterior temporalis and orbicularis oris muscles with electromyographic activity. 40 patients with OSMF were included in the study group, and the patients were divided into four groups on the basis of interincisal mouth opening, i.e. Group I (mouth opening >35 mm), Group II (mouth opening between 30 and 35 mm), Group III (mouth opening between 20 and 30 mm) and Group IV (mouth opening <20 mm). Ultrasonographic cross-sectional thickness and electromyographic activity (amplitude and duration) of the masseter, anterior temporalis and orbicualris oris muscles were recorded in patients with OSMF and 20 controls. Intergroup comparison of ultrasonographic cross-sectional thickness and activity (amplitude and duration) was done, and Pearson's correlation coefficient was applied to find out any relation between ultrasonographic and electromyographic findings. Thickness and activity of the masseter muscle was significantly reduced in Group IV (mouth opening <20 mm) when compared with the control group. The anterior temporalis and orbicularis oris muscles remained unaffected. A positive correlation was observed between the thicknesses of the masseter muscle and the amplitude in Groups I, II and III; the anterior temporalis muscle in Group II and the control group; and the orbicularis oris muscle in Groups II, III and IV. It was concluded that, among the muscles studied, there was an early involvement of the masseter muscle in patients with OSMF compared with that of other muscles.

Length oscillation induces force potentiation in infant guinea pig airway smooth muscle.

PubMed

Wang, Lu; Chitano, Pasquale; Murphy, Thomas M

2005-12-01

Deep inspiration counteracts bronchospasm in normal subjects but triggers further bronchoconstriction in hyperresponsive airways. Although the exact mechanisms for this contrary response by normal and hyperresponsive airways are unclear, it has been suggested that the phenomenon is related to changes in force-generating ability of airway smooth muscle after mechanical oscillation. It is known that healthy immature airways of both humans and animals exhibit hyperresponsiveness. We hypothesize that the profile of active force generation after mechanical oscillation changes with maturation and that this change contributes to the expression of airway hyperresponsiveness in juveniles. We examined the effect of an acute sinusoidal length oscillation on the force-generating ability of tracheal smooth muscle from 1 wk, 3 wk, and 2- to 3-mo-old guinea pigs. We found that the length oscillation produced 15-20% initial reduction in active force equally in all age groups. This was followed by a force recovery profile that displayed striking maturation-specific features. Unique to tracheal strips from 1-wk-old animals, active force potentiated beyond the maximal force generated before oscillation. We also found that actin polymerization was required in force recovery and that prostanoids contributed to the maturation-specific force potentiation in immature airway smooth muscle. Our results suggest a potentiated mechanosensitive contractile property of hyperresponsive airway smooth muscle. This can account for further bronchoconstriction triggered by deep inspiration in hyperresponsive airways.

Training Effectiveness of The Inertial Training and Measurement System

PubMed Central

Naczk, Mariusz; Brzenczek-Owczarzak, Wioletta; Arlet, Jarosław; Naczk, Alicja; Adach, Zdzisław

2014-01-01

The purpose of this study was to evaluate the efficacy of inertial training with different external loads using a new original device - the Inertial Training and Measurement System (ITMS). Forty-six physical education male students were tested. The participants were randomly divided into three training groups and a control group (C group). The training groups performed inertial training with three different loads three times weekly for four weeks. The T0 group used only the mass of the ITMS flywheel (19.4 kg), the T5 and T10 groups had an additional 5 and 10 kg on the flywheel, respectively. Each training session included three exercise sets involving the shoulder joint adductors. Before and after training, the maximal torque and power were measured on an isokinetic dynamometer during adduction of the shoulder joint. Simultaneously, the electromyography activity of the pectoralis major muscle was recorded. Results of the study indicate that ITMS training induced a significant increase in maximal muscle torque in the T0, T5, T10 groups (15.5%, 13.0%, and 14.0%, respectively). Moreover, ITMS training caused a significant increase in power in the T0, T5, T10 groups (16.6%, 19.5%, and 14.5%, respectively). The percentage changes in torque and power did not significantly differ between training groups. Electromyography activity of the pectoralis major muscle increased only in the T0 group after four weeks of training. Using the ITMS device in specific workouts allowed for an increase of shoulder joint adductors torque and power in physical education students. PMID:25713662

A comparative study of different amniotic membrane orientations during extraocular muscle surgery in rabbits.

PubMed

Kassem, Rehab Rashad; El-Mofty, Randa Mohamed Abdel-Moneim; Khodeir, Mustafa Mahmoud; Hamza, Wael Mostafa

2018-03-01

To histopathologically compare the effect of different orientations of cryopreserved human amniotic membrane (AM) transplant during extraocular muscle surgery in rabbits. Fifty-two albino rabbit eyes underwent 4-mm resection of the superior rectus. Eyes were randomly divided into four groups. In Group C (Control group, 16 eyes) the muscle was not wrapped with amniotic membrane. In the three AM groups, cryopreserved AM was wrapped around the muscle, oriented with either its stroma (Group S, 15 eyes) or epithelium (Group E, nine eyes) towards the muscle, or folded on itself with the epithelium externally (Group F, 12 eyes). The rabbits were sacrificed and the eyes were enucleated 6 weeks after surgery. Histopathological examination was conducted for periamniotic, foreign body, scleral, and conjunctival inflammation, conjunctival vascularity, adhesions and muscle fibrosis. In all AM eyes, the AM was surrounded by periamniotic inflammation, with no adhesions detected between the muscle and surrounding tissues in the segment where the AM was present, but detected elsewhere. Adhesions were detected in all group C eyes. Foreign body inflammation was significantly less in Group C than in each of the AM groups (p < .05), but was insignificantly different among the three AM groups (p > .05). Scleral inflammation was absent in all specimens. No significant differences were noted among all groups in terms of conjunctival vascularity, conjunctival inflammation, or muscle fibrosis (p > .05). All AM orientations were equally effective in preventing the development of postoperative adhesions between the extraocular muscle and surrounding tissues.

Skeletal muscle hypertrophy and regeneration: interplay between the myogenic regulatory factors (MRFs) and insulin-like growth factors (IGFs) pathways.

PubMed

Zanou, Nadège; Gailly, Philippe

2013-11-01

Adult skeletal muscle can regenerate in response to muscle damage. This ability is conferred by the presence of myogenic stem cells called satellite cells. In response to stimuli such as injury or exercise, these cells become activated and express myogenic regulatory factors (MRFs), i.e., transcription factors of the myogenic lineage including Myf5, MyoD, myogenin, and Mrf4 to proliferate and differentiate into myofibers. The MRF family of proteins controls the transcription of important muscle-specific proteins such as myosin heavy chain and muscle creatine kinase. Different growth factors are secreted during muscle repair among which insulin-like growth factors (IGFs) are the only ones that promote both muscle cell proliferation and differentiation and that play a key role in muscle regeneration and hypertrophy. Different isoforms of IGFs are expressed during muscle repair: IGF-IEa, IGF-IEb, or IGF-IEc (also known as mechano growth factor, MGF) and IGF-II. MGF is expressed first and is observed in satellite cells and in proliferating myoblasts whereas IGF-Ia and IGF-II expression occurs at the state of muscle fiber formation. Interestingly, several studies report the induction of MRFs in response to IGFs stimulation. Inversely, IGFs expression may also be regulated by MRFs. Various mechanisms are proposed to support these interactions. In this review, we describe the general process of muscle hypertrophy and regeneration and decipher the interactions between the two groups of factors involved in the process.

Muscle dysfunction in chronic obstructive pulmonary disease: update on causes and biological findings

PubMed Central

Pascual, Sergi; Casadevall, Carme; Orozco-Levi, Mauricio; Barreiro, Esther

2015-01-01

Respiratory and/or limb muscle dysfunction, which are frequently observed in chronic obstructive pulmonary disease (COPD) patients, contribute to their disease prognosis irrespective of the lung function. Muscle dysfunction is caused by the interaction of local and systemic factors. The key deleterious etiologic factors are pulmonary hyperinflation for the respiratory muscles and deconditioning secondary to reduced physical activity for limb muscles. Nonetheless, cigarette smoke, systemic inflammation, nutritional abnormalities, exercise, exacerbations, anabolic insufficiency, drugs and comorbidities also seem to play a relevant role. All these factors modify the phenotype of the muscles, through the induction of several biological phenomena in patients with COPD. While respiratory muscles improve their aerobic phenotype (percentage of oxidative fibers, capillarization, mitochondrial density, enzyme activity in the aerobic pathways, etc.), limb muscles exhibit the opposite phenotype. In addition, both muscle groups show oxidative stress, signs of damage and epigenetic changes. However, fiber atrophy, increased number of inflammatory cells, altered regenerative capacity; signs of apoptosis and autophagy, and an imbalance between protein synthesis and breakdown are rather characteristic features of the limb muscles, mostly in patients with reduced body weight. Despite that significant progress has been achieved in the last decades, full elucidation of the specific roles of the target biological mechanisms involved in COPD muscle dysfunction is still required. Such an achievement will be crucial to adequately tackle with this relevant clinical problem of COPD patients in the near-future. PMID:26623119

Changes in energy metabolism in the quadriceps femoris after a single bout of acute exhaustive swimming in rats: a ³¹P-magnetic resonance spectroscopy study.

PubMed

Sun, Yingwei; Pan, Shinong; Chen, Zhian; Zhao, Heng; Ma, Ying; Zheng, Liqiang; Li, Qi; Deng, Chunbo; Fu, Xihu; Lu, Zaiming; Guo, Qiyong

2014-01-01

Little is known about the value of (31)P-magnetic resonance spectroscopy ((31)P-MRS) in in vivo assessment of exhaustive exercise-induced injury in skeletal muscle. We aimed to evaluate the value of a (31)P-MRS study using the quadriceps femoris after a single bout of acute exhaustive swimming in rats, and the correlation between (31)P-MRS and histological changes. Sixty male Sprague-Dawley rats were randomly assigned to control, half-exhaustive, and exhaustive exercise groups. (31)P-MRS of the quadriceps femoris of the right lower limb was performed immediately after swimming exercise to detect Pi, PCr, and β-ATP. The Pi/PCr, Pi/β-ATP, PCr/β-ATP, and PCr/(PCr+Pi) were calculated and pH measured. Areas under the receiver operating characteristic curve (AUCs) were calculated to evaluate the diagnostic potential of (31)P-MRS in identifying and distinguishing the three groups. HE staining, electron microscopy and desmin immunostaining after imaging of the muscle were used as a reference standard. The correlation between (31)P-MRS and the mean absorbance (A value) of desmin staining were analyzed with the Pearson correlation test. Pi, PCr, Pi/PCr, and PCr/(PCr+Pi) showed statistically significant intergroup differences (P < 0.05). AUCs of Pi, PCr, Pi/PCr, and PCr/(PCr+Pi) were 0.905, 0.848, 0.930, and 0.930 for the control and half-exhaustive groups, while sensitivity and specificity were 90%/85%, 95%/55%, 95%/80%, and 90%/85%, respectively. The AUCs of Pi, PCr, Pi/PCr and PCr/(PCr+Pi) were 0.995, 0.980, 1.000, and 1.000 for the control and exhaustive groups, while sensitivity and specificity were 95%/90%, 100%/90%, 100%/95%, and 100%/95%, respectively. The AUCs of Pi, PCr, Pi/PCr, and PCr/(PCr+Pi) were 0.735, 0.865, 0.903, and 0.903 for the half-exhaustive and exhaustive groups, while sensitivity and specificity were 80%/60%, 90%/75%, 95%/65%, and 95%/70%, respectively. In the half-exhaustive group, some muscle fibers exhibited edema in HE staining, and the unclear Z-discs and the mitochondria with vacuolar degeneration under electron microscopy. Compared with the half-exhaustive group, muscle fiber edema was increased in the exhaustive group, and the Z-discs were broken and the mitochondria exhibited marked vacuolar degeneration under electron microscopy. There were significant difference in A values of desmin staining in the right vastus lateralis among the control, half-exhaustive, and exhaustive groups with 0.58 ± 0.06, 0.30 ± 0.04, and 0.21 ± 0.02, respectively (P < 0.05). Histological examination also showed injury-induced changes in the vastus lateralis among the different intensities groups. Statistically a moderate correlation between (31)P-MRS and desmin was observed, the correlation coefficients of Pi, PCr, Pi/PCr, and PCr/(PCr+Pi) were -0.706, 0.709, -0.726, and 0.791, respectively (P < 0.01). (31)P-MRS can effectively reflect the changes in energy metabolism in the skeletal muscle after a single bout of acute exhaustive swimming in rats. Based on the significant correlation between (31)P-MRS parameters and histological changes, the changes of Pi, PCr, Pi/PCr, and PCr/(PCr+Pi) can indirectly reflect the degree of exercise-induced injury.

Motor plan differs for young and older adults during similar movements.

PubMed

Casamento-Moran, Agostina; Chen, Yen-Ting; Lodha, Neha; Yacoubi, Basma; Christou, Evangelos A

2017-04-01

Older adults exhibit altered activation of the agonist and antagonist muscles during goal-directed movements compared with young adults. However, it remains unclear whether the differential activation of the antagonistic muscles in older adults results from an impaired motor plan or an altered ability of the muscle to contract. The purpose of this study, therefore, was to determine whether the motor plan differs for young and older adults. Ten young (26.1 ± 4.3 yr, 4 women) and 16 older adults (71.9 ± 6.9 yr, 9 women) participated in the study. Participants performed 100 trials of fast goal directed movements with ankle dorsiflexion while we recorded the electromyographic activity of the primary agonist (tibialis anterior; TA) and antagonist (soleus; SOL) muscles. From those 100 trials we selected 5 trials in each of 3 movement end-point categories (fast, accurate, and slow). We investigated age-associated differences in the motor plan by quantifying the individual activity and coordination of the agonist and antagonist muscles. During similar movement end points, older adults exhibited similar activation of the agonist (TA) and antagonist (SOL) muscles compared with young adults. In addition, the coordination of the agonist and antagonist muscles (TA and SOL) was different between the two age groups. Specifically, older adults exhibited lower TA-SOL overlap ( F 1,23 = 41.2, P < 0.001) and greater TA-SOL peak EMG delay ( F 1,25 = 35.5, P < 0.001). This finding suggests that although subjects in both age groups displayed similar movement end points, they exhibited a different motor plan, as demonstrated by altered coordination between the agonist and antagonist muscles. NEW & NOTEWORTHY We aimed to determine whether the altered activation of muscles in older adults compared with young adults during fast goal-directed movements is related to an altered motor plan. For matched movements, there were differences in the coordination of antagonistic muscles but no differences in the individual activation of muscles. We provide novel evidence that the differential activation of muscles in older adults is related to an altered motor plan. Copyright © 2017 the American Physiological Society.

Normal Muscle Oxygen Consumption and Fatigability in Sickle Cell Patients Despite Reduced Microvascular Oxygenation and Hemorheological Abnormalities

PubMed Central

Waltz, Xavier; Pichon, Aurélien; Lemonne, Nathalie; Mougenel, Danièle; Lalanne-Mistrih, Marie-Laure; Lamarre, Yann; Tarer, Vanessa; Tressières, Benoit; Etienne-Julan, Maryse; Hardy-Dessources, Marie-Dominique; Hue, Olivier; Connes, Philippe

2012-01-01

Background/Aim Although it has been hypothesized that muscle metabolism and fatigability could be impaired in sickle cell patients, no study has addressed this issue. Methods We compared muscle metabolism and function (muscle microvascular oxygenation, microvascular blood flow, muscle oxygen consumption and muscle microvascular oxygenation variability, which reflects vasomotion activity, maximal muscle force and local muscle fatigability) and the hemorheological profile at rest between 16 healthy subjects (AA), 20 sickle cell-hemoglobin C disease (SC) patients and 16 sickle cell anemia (SS) patients. Results Muscle microvascular oxygenation was reduced in SS patients compared to the SC and AA groups and this reduction was not related to hemorhelogical abnormalities. No difference was observed between the three groups for oxygen consumption and vasomotion activity. Muscle microvascular blood flow was higher in SS patients compared to the AA group, and tended to be higher compared to the SC group. Multivariate analysis revealed that muscle oxygen consumption was independently associated with muscle microvascular blood flow in the two sickle cell groups (SC and SS). Finally, despite reduced muscle force in sickle cell patients, their local muscle fatigability was similar to that of the healthy subjects. Conclusions Sickle cell patients have normal resting muscle oxygen consumption and fatigability despite hemorheological alterations and, for SS patients only, reduced muscle microvascular oxygenation and increased microvascular blood flow. Two alternative mechanisms can be proposed for SS patients: 1) the increased muscle microvascular blood flow is a way to compensate for the lower muscle microvascular oxygenation to maintain muscle oxygen consumption to normal values or 2) the reduced microvascular oxygenation coupled with a normal resting muscle oxygen consumption could indicate that there is slight hypoxia within the muscle which is not sufficient to limit mitochondrial respiration but increases muscle microvascular blood flow. PMID:23285055

Head to Head Comparison of Short-Term Treatment with the NAD(+) Precursor Nicotinamide Mononucleotide (NMN) and 6 Weeks of Exercise in Obese Female Mice.

PubMed

Uddin, Golam M; Youngson, Neil A; Sinclair, David A; Morris, Margaret J

2016-01-01

Obesity is well known to be a major cause of several chronic metabolic diseases, which can be partially counteracted by exercise. This is due, in part, to an upregulation of mitochondrial activity through increased nicotinamide adenine dinucleotide (NAD(+)). Recent studies have shown that NAD(+) levels can be increased by using the NAD(+) precursor, nicotinamide mononucleotide (NMN) leading to the suggestion that NMN could be a useful intervention in diet related metabolic disorders. In this study we compared the metabolic, and especially mitochondrial-associated, effects of exercise and NMN in ameliorating the consequences of high-fat diet (HFD) induced obesity in mice. Sixty female 5 week old C57BL6/J mice were allocated across five groups: Chow sedentary: CS; Chow exercise: CEX; HFD sedentary: HS; HFD NMN: HNMN; HFD exercise: HEX (12/group). After 6 weeks of diet, exercise groups underwent treadmill exercise (15 m/min for 45 min), 6 days per week for 6 weeks. NMN or vehicle (500 mg/kg body weight) was injected (i.p.) daily for the last 17 days. No significant alteration in body weight was observed in response to exercise or NMN. The HFD significantly altered adiposity, glucose tolerance, plasma insulin, NADH levels and citrate synthase activity in muscle and liver. HEX and HNMN groups both showed significantly improved glucose tolerance compared to the HS group. NAD(+) levels were increased significantly both in muscle and liver by NMN whereas exercise increased NAD(+) only in muscle. Both NMN and exercise ameliorated the HFD-induced reduction in liver citrate synthase activity. However, exercise, but not NMN, ameliorated citrate synthase activity in muscle. Overall these data suggest that while exercise and NMN-supplementation can induce similar reversal of the glucose intolerance induced by obesity, they are associated with tissue-specific effects and differential alterations to mitochondrial function in muscle and liver.

Muscle strength and kinetic gait pattern in children with bilateral spastic CP.

PubMed

Eek, Meta Nyström; Tranberg, Roy; Beckung, Eva

2011-03-01

Cerebral palsy is often associated with an abnormal gait pattern. This study put focus on relation between muscle strength and kinetic gait pattern in children with bilateral spastic cerebral palsy and compares them with a reference group. In total 20 children with CP and 20 typically developing children participated. They were all assessed with measurement of muscle strength in eight muscle groups in the legs and a 3-dimensional gait analysis including force data. It was found that children with CP were not only significantly weaker in all muscle groups but also walked with slower velocity and shorter stride length when compared with the reference group. Gait moments differed at the ankle level with significantly lower moments in children with CP. Gait moments were closer to the maximal muscle strength in the group of children with CP. Furthermore a correlation between plantarflexing gait moment and muscle strength was observed in six of the eight muscle groups in children with CP, a relation not found in the reference group. A similar pattern was seen between muscle strength and generating ankle power with a rho=0.582-0.766. The results of this study state the importance of the relationship of the overall muscle strength pattern in the lower extremity, not only the plantarflexors. Copyright © 2010 Elsevier B.V. All rights reserved.

Effects of the bilateral isokinetic strengthening training on functional parameters, gait, and the quality of life in patients with stroke.

PubMed

Büyükvural Şen, Sıdıka; Özbudak Demir, Sibel; Ekiz, Timur; Özgirgin, Neşe

2015-01-01

To evaluate the effects of the bilateral isokinetic strengthening training applied to knee and ankle muscles on balance, functional parameters, gait, and the quality of in stroke patients. Fifty patients (33 M, 17 F) with subacute-chronic stroke and 30 healthy subjects were included. Stroke patients were allocated into isokinetic and control groups. Conventional rehabilitation program was applied to all cases; additionally maximal concentric isokinetic strengthening training was applied to the knee-ankle muscles bilaterally to the isokinetic group 5 days a week for 3 weeks. Biodex System 3 Pro Multijoint System isokinetic dynamometer was used for isokinetic evaluation. The groups were assessed by Functional Independence Measure, Stroke Specific Quality of Life Scale, Timed 10-Meter Walk Test, Six-Minute Walk Test, Stair-Climbing Test, Timed up&go Test, Berg Balance Scale, and Rivermead Mobility Index. Compared with baseline, the isokinetic PT values of the knee and ankle on both sides significantly increased in all cases. PT change values were significantly higher in the isokinetic group than the control group (P<0.025). Furthermore, the quality of life, gait, balance and mobility index values improved significantly in both groups, besides the increase levels were found significantly higher in the isokinetic group (P<0.025, P<0.05). Bilateral isokinetic strengthening training in addition to conventional rehabilitation program after stroke seems to be effective on strengthening muscles on both sides, improving functional parameters, gait, balance and life quality.

Effects of the bilateral isokinetic strengthening training on functional parameters, gait, and the quality of life in patients with stroke

PubMed Central

Büyükvural Şen, Sıdıka; Özbudak Demir, Sibel; Ekiz, Timur; Özgirgin, Neşe

2015-01-01

Objective: To evaluate the effects of the bilateral isokinetic strengthening training applied to knee and ankle muscles on balance, functional parameters, gait, and the quality of in stroke patients. Methods: Fifty patients (33 M, 17 F) with subacute-chronic stroke and 30 healthy subjects were included. Stroke patients were allocated into isokinetic and control groups. Conventional rehabilitation program was applied to all cases; additionally maximal concentric isokinetic strengthening training was applied to the knee-ankle muscles bilaterally to the isokinetic group 5 days a week for 3 weeks. Biodex System 3 Pro Multijoint System isokinetic dynamometer was used for isokinetic evaluation. The groups were assessed by Functional Independence Measure, Stroke Specific Quality of Life Scale, Timed 10-Meter Walk Test, Six-Minute Walk Test, Stair-Climbing Test, Timed up&go Test, Berg Balance Scale, and Rivermead Mobility Index. Results: Compared with baseline, the isokinetic PT values of the knee and ankle on both sides significantly increased in all cases. PT change values were significantly higher in the isokinetic group than the control group (P<0.025). Furthermore, the quality of life, gait, balance and mobility index values improved significantly in both groups, besides the increase levels were found significantly higher in the isokinetic group (P<0.025, P<0.05). Conclusion: Bilateral isokinetic strengthening training in addition to conventional rehabilitation program after stroke seems to be effective on strengthening muscles on both sides, improving functional parameters, gait, balance and life quality. PMID:26629238

Using 4+ to grade near-normal muscle strength does not improve agreement.

PubMed

O'Neill, Søren; Jaszczak, Sofie Louise Thomsen; Steffensen, Anne Katrine Søndergaard; Debrabant, Birgit

2017-01-01

Manual assessment of muscle strength is often graded using the ordinal Medical Research Council (MRC) scale. The scale has a number of inherent weaknesses, including poorly defined limits between grades '4' and '5' and very large differences in the span of muscle strength encompassed by each of the six grades. It is not necessarily obvious how to convert a manual muscle test finding into an MRC grade. Several modifications which include intermediate grades have been suggested to improve the MRC scale and the current study examines whether agreement improves and variation in ratings decrease, with an intermediate grade between '4' and '5', in circumstances where such a grade would seem appropriate. The present study examined the hypothesis, that a modified MRC-scale which included the commonly used '4+' option, resulted in greater agreement between clinicians compared to the standard MRC-scale. A questionnaire containing five simple clinical cases were distributed to a large convenience sample of chiropractors in Northern Europe, with instructions to grade the described muscle strength findings using the MRC scale. The scale was adapted (with/without an intermediate '4+' grade) depending on the preference of the individual respondent. The cases were designed in such a way as to suggest a muscle weakness in the grey area between '4' and '5', i.e. grade '4+' on the modified MRC scale. A total of 225 questionnaires were returned (7% response rate). The average percentage agreement (across cases) in the standard MRC group was 64% [range 51%: 73%] (grade '4' in all cases). In the modified MRC group, the corresponding findings was 48% [38%: 74%] (grade '4' or '4+' in all cases). The mean average deviation analogue in the standard MRC group was 0.34 (range 0.34: 0.40), compared to 0.51 (range 0.39: 0.73) in the modified MRC group, indicating greater dispersion of scores in the modified MRC group. The Fleiss kappa was 0.02 ( p  < 0.001) and 0.13 ( p  < 0.001), respectively. Contrary to the original hypothesis, introduction of a '4+' grade did not clearly improve agreement or variability of ratings, despite eliminating the physical muscle testing by providing written descriptions of test findings and specifically designing these to suggest a weakness of grade '4+'.

Vastus lateralis and rectus femoris echo intensity fail to reflect knee extensor specific tension in middle-school boys.

PubMed

Mota, Jacob A; Stock, Matt S; Thompson, Brennan J

2017-07-26

The potential dissociation between muscle strength and size has led to interest in the ability to assess muscle quality across the lifespan. We examined the association between echo intensity and specific tension in middle-school boys. Twenty-five boys participated in this study. Sixteen (mean  ±  SD age  =  12  ±  1 years) engaged in a 16-week after-school strength and conditioning program. Nine boys (12  ±  1 years) served as controls. The program involved two 90 min sessions per week of lower-body speed, power, and resistance training. Before and after the intervention, ultrasound imaging was used to quantify vastus lateralis and rectus femoris echo intensity. Specific tension was calculated as voluntary isometric peak torque divided by dual energy x-ray absorptiometry-derived thigh lean mass (Nm kg -1 ). The pretest echo intensity and specific tension data were not significantly correlated (r  =  0.040, p  =  0.850). Training resulted in a small mean increase in specific tension (change  =  1.93 Nm kg -1 ; d  =  0.42). The echo intensity values were not affected by training or maturation (training change  =  -1.13 arbitrary units (A.U.); control  =  0.00 A.U.). Both variables showed no interaction and no group or time main effects. The echo intensity and specific tension change scores were not correlated for all subjects (r  =  -0.080, p  =  0.705) or groups (training r  =  -0.095, p  =  0.727; control r  =  -0.004, p  =  0.992). In middle-school boys, a relationship between echo intensity and the ratio of muscle strength relative to lean mass does not exist.

Low muscle mass and risk of type 2 diabetes in middle-aged and older adults: findings from the KoGES.

PubMed

Son, Jang Won; Lee, Seong Su; Kim, Sung Rae; Yoo, Soon Jib; Cha, Bong Yun; Son, Ho Young; Cho, Nam H

2017-05-01

Asians have a propensity to develop type 2 diabetes with a lower BMI than Western populations. This discrepancy may be due to differences in body fat and muscle mass for a given BMI. However, unlike adiposity, it is unclear whether muscle mass affects the risk of type 2 diabetes in Asian populations. We conducted a 2-yearly prospective assessment of 6895 participants who were free of diabetes at the baseline examination as part of the Korean Genome Epidemiology Study. The muscle mass index (MMI) was defined as the weight-adjusted appendicular skeletal muscle mass. Using Cox regression models, we evaluated the association between MMI and the risk of developing type 2 diabetes across sex-specific tertiles of MMI. Low muscle mass was defined as the sex-specific lowest tertile of MMI. Main covariates included age, sex, urban or rural residence, family history of diabetes, hypertension, smoking status, education level, monthly income, physical activity, alcohol consumption and diet. In addition, body fat mass, waist circumference and BMI were controlled as categorical variables. Obesity was defined as a BMI of ≥25 kg/m 2 or a waist circumference of ≥90 cm for men and ≥85 cm for women. During a median follow-up of 9.06 years, 1336 participants developed type 2 diabetes. At baseline, the mean age was 52.1 years and the mean BMI was 24.4 kg/m 2 . The mean MMI for men and women was 32.1% and 26.0%, respectively. There was an inverse association between MMI and the risk of type 2 diabetes. Multivariate-adjusted HRs for the risk of developing type 2 diabetes were 2.05 (95% CI 1.73, 2.43), 1.39 (95% CI 1.17, 1.66) and 1.0 from the lowest to highest sex-specific MMI tertile, with an HR of 1.35 (95% CI 1.26, 1.45) per SD decline in MMI. Further adjustments for fat mass, waist circumference and BMI as categorical variables did not modify the relationship (each p < 0.01). In BMI-stratified analyses, the population-attributable fraction of the lowest tertile of MMI for developing type 2 diabetes was increased by 11.9% in the non-obese group and 19.7% in the obese group. Low muscle mass as defined by MMI was associated with an increased risk of type 2 diabetes, independent of general obesity, in middle-aged and older Korean adults.

Anatomical study of the final common pathway for vocalization in the cat

NASA Technical Reports Server (NTRS)

Holstege, Gert

1989-01-01

Results are presented of an anatomical study of the neuronal pathways in the cat, via which the periaqueductal gray (PAG) produces excitation of motoneurons involved in vocalization. It is shown that a specific cell group in the lateral part of the caudal PAG and in the tegmentum just lateral to it projects bilaterally to the nucleus retroambiguus (NRA) in the caudal medulla oblongata. Neurons in the NRA in turn project, via a contralateral pathway through the ventral funiculus of the spinal cord, to the motoneuronal cell groups innervating intercostal and abdominal muscles. In the brainstem, the NRA neurons project to the motoneuronal cell groups innervating mouth-opening and perioral muscles as well as to motoneurons innervating the pharynx, soft palate, and tongue. These results indicate that the projections from PAG via NRA to vocalization motoneurons form the final common pathway in vocalization.

Relationship between muscle mass and physical performance: is it the same in older adults with weak muscle strength?

PubMed

Kim, Kyoung-Eun; Jang, Soong-Nang; Lim, Soo; Park, Young Joo; Paik, Nam-Jong; Kim, Ki Woong; Jang, Hak Chul; Lim, Jae-Young

2012-11-01

the relationship between muscle mass and physical performance has not been consistent among studies. to clarify the relationship between muscle mass and physical performance in older adults with weak muscle strength. cross-sectional analysis using the baseline data of 542 older men and women from the Korean Longitudinal Study on Health and Aging. dual X-ray absorptiometry, isokinetic dynamometer and the Short Physical Performance Battery (SPPB) were performed. Two muscle mass parameters, appendicular skeletal mass divided by weight (ASM/Wt) and by height squared (ASM/Ht(2)), were measured. We divided the participants into a lower-quartile (L25) group and an upper-three-quartiles (H75) group based on the knee-extensor peak torque. Correlation analysis and logistic regression models were used to assess the association between muscle mass and low physical performance, defined as SPPB scores <9, after controlling for confounders. in the L25 group, no correlation between mass and SPPB was detected, whereas the correlation between peak torque and SPPB was significant and higher than that in the H75 group. Results from the logistic models also showed no association between muscle mass and SPPB in the L25 group, whereas muscle mass was associated with SPPB in the H75 group. muscle mass was not associated with physical performance in weak older adults. Measures of muscle strength may be of greater clinical importance in weak older adults than is muscle mass per se.

The effect of electrical muscle stimulation on the prevention of disuse muscle atrophy in patients with consciousness disturbance in the intensive care unit.

PubMed

Hirose, Tomoya; Shiozaki, Tadahiko; Shimizu, Kentaro; Mouri, Tomoyoshi; Noguchi, Kazuo; Ohnishi, Mitsuo; Shimazu, Takeshi

2013-08-01

Disuse atrophy of the lower limbs of patients with consciousness disturbance has often been recognized as "an unavoidable consequence," such that the mechanism was not investigated diligently. In this study, we examined the preventive effects of electrical muscle stimulation (EMS) against disuse atrophy of the lower limbs in patients in coma after stroke or traumatic brain injury in the intensive care unit. We evaluated changes in cross-sectional area of lower limb muscles weekly with computed tomography in 6 control group patients and 9 EMS group patients. Electrical muscle stimulation was performed daily from day 7 after admission. We evaluated the anterior thigh muscle compartment, posterior thigh muscle compartment, anterior leg muscle compartment, and posterior leg muscle compartment. In the control group, the decrease in cross-sectional area progressed in all compartments every week (P < .0001). Cross-sectional areas of all compartments at day 14 were significantly decreased in the control group compared with those in the EMS group at day 7 (P < .001). We were able to limit the rate of muscle atrophy as measured in the cross-sectional areas to within 4% during the period of EMS (days 7-42) in 5 patients. The difference between the control and the EMS groups was statistically significant (P < .001). Electrical muscle stimulation is effective in the prevention of disuse muscle atrophy in patients with consciousness disorder. Copyright © 2013 Elsevier Inc. All rights reserved.

Beneficial Autophagic Activities, Mitochondrial Function, and Metabolic Phenotype Adaptations Promoted by High-Intensity Interval Training in a Rat Model

PubMed Central

Li, Fang-Hui; Li, Tao; Ai, Jing-Yi; Sun, Lei; Min, Zhu; Duan, Rui; Zhu, Ling; Liu, Yan-ying; Liu, Timon Cheng-Yi

2018-01-01

The effects of high-intensity interval (HIIT) and moderate-intensity continuous training (MICT) on basal autophagy and mitochondrial function in cardiac and skeletal muscle and plasma metabolic phenotypes have not been clearly characterized. Here, we investigated how 10-weeks HIIT and MICT differentially modify basal autophagy and mitochondrial markers in cardiac and skeletal muscle and conducted an untargeted metabolomics study with proton nuclear magnetic resonance (1H NMR) spectroscopy and multivariate statistical analysis of plasma metabolic phenotypes. Male Sprague–Dawley rats were separated into three groups: sedentary control (SED), MICT, and HIIT. Rats underwent evaluation of exercise performance, including exercise tolerance and grip strength, and blood lactate levels were measured immediately after an incremental exercise test. Plasma samples were analyzed by 1H NMR. The expression of autophagy and mitochondrial markers and autophagic flux (LC3II/LC3-I ratio) in cardiac, rectus femoris, and soleus muscle were analyzed by western blotting. Time to exhaustion and grip strength increased significantly following HIIT compared with that in both SED and MICT groups. Compared with those in the SED group, blood lactate level, and the expression of SDH, COX-IV, and SIRT3 significantly increased in rectus femoris and soleus muscle of both HIIT and MICT groups. Meanwhile, SDH and COX-IV content of cardiac muscle and COX-IV and SIRT3 content of rectus femoris and soleus muscle increased significantly following HIIT compared with that following MICT. The expression of LC3-II, ATG-3, and Beclin-1 and LC3II/LC3-I ratio were significantly increased only in soleus and cardiac muscle following HIIT. These data indicate that HIIT was more effective for improving physical performance and facilitating cardiac and skeletal muscle adaptations that increase mitochondrial function and basal autophagic activities. Moreover, 1H NMR spectroscopy and multivariate statistical analysis identified 11 metabolites in plasma, among which fine significantly and similarly changed after both HIIT and MICT, while BCAAs isoleucine, leucine, and valine and glutamine were changed only after HIIT. Together, these data indicate distinct differences in specific metabolites and autophagy and mitochondrial markers following HIIT vs. MICT and highlight the value of metabolomic analysis in providing more detailed insight into the metabolic adaptations to exercise training. PMID:29875683

Beneficial Autophagic Activities, Mitochondrial Function, and Metabolic Phenotype Adaptations Promoted by High-Intensity Interval Training in a Rat Model.

PubMed

Li, Fang-Hui; Li, Tao; Ai, Jing-Yi; Sun, Lei; Min, Zhu; Duan, Rui; Zhu, Ling; Liu, Yan-Ying; Liu, Timon Cheng-Yi

2018-01-01

The effects of high-intensity interval (HIIT) and moderate-intensity continuous training (MICT) on basal autophagy and mitochondrial function in cardiac and skeletal muscle and plasma metabolic phenotypes have not been clearly characterized. Here, we investigated how 10-weeks HIIT and MICT differentially modify basal autophagy and mitochondrial markers in cardiac and skeletal muscle and conducted an untargeted metabolomics study with proton nuclear magnetic resonance ( 1 H NMR) spectroscopy and multivariate statistical analysis of plasma metabolic phenotypes. Male Sprague-Dawley rats were separated into three groups: sedentary control (SED), MICT, and HIIT. Rats underwent evaluation of exercise performance, including exercise tolerance and grip strength, and blood lactate levels were measured immediately after an incremental exercise test. Plasma samples were analyzed by 1 H NMR. The expression of autophagy and mitochondrial markers and autophagic flux (LC3II/LC3-I ratio) in cardiac, rectus femoris, and soleus muscle were analyzed by western blotting. Time to exhaustion and grip strength increased significantly following HIIT compared with that in both SED and MICT groups. Compared with those in the SED group, blood lactate level, and the expression of SDH, COX-IV, and SIRT3 significantly increased in rectus femoris and soleus muscle of both HIIT and MICT groups. Meanwhile, SDH and COX-IV content of cardiac muscle and COX-IV and SIRT3 content of rectus femoris and soleus muscle increased significantly following HIIT compared with that following MICT. The expression of LC3-II, ATG-3, and Beclin-1 and LC3II/LC3-I ratio were significantly increased only in soleus and cardiac muscle following HIIT. These data indicate that HIIT was more effective for improving physical performance and facilitating cardiac and skeletal muscle adaptations that increase mitochondrial function and basal autophagic activities. Moreover, 1 H NMR spectroscopy and multivariate statistical analysis identified 11 metabolites in plasma, among which fine significantly and similarly changed after both HIIT and MICT, while BCAAs isoleucine, leucine, and valine and glutamine were changed only after HIIT. Together, these data indicate distinct differences in specific metabolites and autophagy and mitochondrial markers following HIIT vs. MICT and highlight the value of metabolomic analysis in providing more detailed insight into the metabolic adaptations to exercise training.

[The expressions of HSP 70 mRNA and c-fos mRNA in the skeletal muscle and cardiac muscle of rabbits by electrocuted].

PubMed

Wang, Ye; Liu, Min; Cheng, Wei-bo; He, Gui-qiong; Li, Fan; Liao, Zhi-gang

2008-08-01

To study the changes of HSP 70 mRNA and c-fos mRNA expression and to find a method to differentiate antemortem from postmortem electrocution. Fifteen New Zealand rabbits were randomly divided into three groups, the antemortem electrocution group, the postmortem electrocution group, and the control group. Each group consists of five rabbits. The levels of HSP 70 mRNA and c-fos mRNA in skeletal muscle and cardiac muscle were examined with quantitative fluorescent RT-PCR. The levels of HSP 70 mRNA and c-fos mRNA in the antemortem electrocution group increased significantly (P<0.05), compared with that of the postmortem electrocution group. The changes of HSP 70 mRNA and c-fos mRNA expression in skeletal muscle and cardiac muscle can be used as an indicator to distinguish antemortem from postmortem electrocution.

Time to Maximal Voluntary Isometric Contraction (MVC) for Five Different Muscle Groups in College Adults.

ERIC Educational Resources Information Center

Morris, A. F.; And Others

1983-01-01

College men and women were studied to ascertain the force-time components of a rapid voluntary muscle contraction for five muscle groups. Researchers found that the time required for full contraction differs: (1) in men and women; and (2) among the five muscle groups. (Authors/PP)

Effect of rapid rigor mortis processes on protein functionality in pectoralis major muscle of domestic turkeys.

PubMed

Pietrzak, M; Greaser, M L; Sosnicki, A A

1997-08-01

The pale, soft, exudative (PSE) phenomenon in turkey pectoralis major (breast) muscle was studied using a combination of biochemical, meat quality, microscopic, and gel electrophoresis techniques. Breast muscle samples were collected from turkeys characterized by slow vs fast postmortem glycolysis assessed by muscle pH at 20 min after death. The PSE group was characterized by lower muscle ATP (P < .05) and higher lactate levels (P < .05) compared with the normal group. Excess water-holding capacity and cooking yield were significantly lower (P < .05) in the PSE group than in normal turkeys. Breast muscle of the PSE group was also lighter (P < .05) than that in the normal group as determined by Minolta L* values. The SDS-PAGE, Western blotting, and immunofluorescence microscopy revealed that phosphorylase, a soluble enzyme, became tightly associated with the myofibrils in muscle from the PSE group. Also, less myosin could be solubilized from PSE vs normal myofibril samples. The results indicate that irreversible myosin insolubility due to low pH and high-temperature conditions is decisive in the development of PSE turkey breast muscle.

Fatigue-related firing of muscle nociceptors reduces voluntary activation of ipsilateral but not contralateral lower limb muscles.

PubMed

Kennedy, David S; Fitzpatrick, Siobhan C; Gandevia, Simon C; Taylor, Janet L

2015-02-15

During fatiguing upper limb exercise, maintained firing of group III/IV muscle afferents can limit voluntary drive to muscles within the same limb. It is not known if this effect occurs in the lower limb. We investigated the effects of group III/IV muscle afferent firing from fatigued ipsilateral and contralateral extensor muscles and ipsilateral flexor muscles of the knee on voluntary activation of the knee extensors. In three experiments, we examined voluntary activation of the knee extensors by measuring changes in superimposed twitches evoked by femoral nerve stimulation. Subjects attended on 2 days for each experiment. On one day a sphygmomanometer cuff occluded blood flow of the fatigued muscles to maintain firing of group III/IV muscle afferents. After a 2-min extensor contraction (experiment 1; n = 9), mean voluntary activation was lower with than without maintained ischemia (47 ± 19% vs. 87 ± 8%, respectively; P < 0.001). After a 2-min knee flexor maximal voluntary contraction (MVC) (experiment 2; n = 8), mean voluntary activation was also lower with than without ischemia (59 ± 21% vs. 79 ± 9%; P < 0.01). After the contralateral (left) MVC (experiment 3; n = 8), mean voluntary activation of the right leg was similar with or without ischemia (92 ± 6% vs. 93 ± 4%; P = 0.65). After fatiguing exercise, activity in group III/IV muscle afferents reduces voluntary activation of the fatigued muscle and nonfatigued antagonist muscles in the same leg. However, group III/IV muscle afferents from the fatigued left leg had no effect on the unfatigued right leg. This suggests that any "crossover" of central fatigue in the lower limbs is not mediated by group III/IV muscle afferents. Copyright © 2015 the American Physiological Society.

Chinese Massage Combined with Herbal Ointment for Athletes with Nonspecific Low Back Pain: A Randomized Controlled Trial

PubMed Central

Kong, Ling Jun; Fang, Min; Zhan, Hong Sheng; Yuan, Wei An; Tao, Ji Ming; Qi, Gao Wei; Cheng, Ying Wu

2012-01-01

Non-specific low back pain (NLBP) is an increasing health problem for athletes. This randomized controlled trial was designed to investigate the effects of Chinese massage combined with herbal ointment for NLBP. 110 athletes with NLBP were randomly assigned to experimental group with Chinese massage combined with herbal ointment or control group with simple massage therapy. The primary outcome was pain by Chinese Short Form McGill Pain Questionnaire (C-SFMPQ). The secondary outcome was local muscle stiffness by Myotonometer. After 4 weeks, the experimental group experienced significant improvements in C-SFMPQ and in local muscle stiffness compared with control group (between-group difference in mean change from baseline, −1.24 points, P = 0.005 in sensory scores; −3.14 points, P < 0.001 in affective scores; −4.39 points, P < 0.001 in total scores; −0.64 points, P = 0.002 in VAS; −1.04 points, P = 0.005 in local muscle stiffness during relaxation state). The difference remained at one month followup, but it was only significant in affective scores (−2.83 points, P < 0.001) at three months followup. No adverse events were observed. These findings suggest that Chinese massage combined with herbal ointment may be a beneficial complementary and alternative therapy for athletes with NLBP. PMID:23258996

Effects of balance training by knee joint motions on muscle activity in adult men with functional ankle instability.

PubMed

Nam, Seung-Min; Kim, Won-Bok; Yun, Chang-Kyo

2016-05-01

[Purpose] This study examined the effects of balance training by applying knee joint movements on muscle activity in male adults with functional ankle instability. [Subjects and Methods] 28 adults with functional ankle instability, divided randomly into an experimental group, which performed balance training by applying knee joint movements for 20 minutes and ankle joint exercises for 10 minutes, and a control group, which performed ankle joint exercise for 30 minutes. Exercises were completed three times a week for 8 weeks. Electromyographic values of the tibialis anterior, peroneus longus, peroneus brevis, and the lateral gastrocnemius muscles were obtained to compare and analyze muscle activity before and after the experiments in each group. [Results] The experimental group had significant increases in muscle activity in the tibialis anterior, peroneus longus, and lateral gastrocnemius muscles, while muscle activity in the peroneus brevis increased without significance. The control group had significant increases in muscle activity in the tibialis anterior and peroneus longus, while muscle activity in the peroneus brevis and lateral gastrocnemius muscles increased without significance. [Conclusion] In conclusion, balance training by applying knee joint movements can be recommended as a treatment method for patients with functional ankle instability.

Contractile properties of single permeabilized muscle fibers from congenital cleft palates and normal palates of Spanish goats.

PubMed

Hanes, Michael C; Weinzweig, Jeffrey; Kuzon, William M; Panter, Kip E; Buchman, Steven R; Faulkner, John A; Yu, Deborah; Cederna, Paul S; Larkin, Lisa M

2007-05-01

Analysis of the composition of muscle fibers constituent to a cleft palate could provide significant insight into the cause of velopharyngeal inadequacy. The authors hypothesized that levator veli palatini muscle dysfunction inherent to cleft palates could affect the timing and outcome of cleft palate repair. Single, permeabilized muscle fibers from levator veli palatini muscles of three normal (n = 19 fibers) and three chemically induced congenital cleft palates (n = 21 fibers) of 14-month-old goats were isolated, and contractile properties were evaluated. The maximum isometric force and rate constants of tension redevelopment (ktr) were measured, and the specific force and normalized power were calculated for each fiber. The ktr measures indicate that cleft fibers are predominantly fast-fatigable; normal fibers are slow fatigue-resistant: after a 10-minute isometric contraction, fibers from cleft palates had a loss of force 16 percent greater than that from normal palates (p = 0.0001). The cross-sectional areas of the fibers from cleft palates (2750 +/- 209 microm2) were greater (p = 0.05) than those from normal palates (2226 +/- 143 microm2). Specific forces did not differ between the two groups. Maximum normalized power of fibers from cleft palates (11.05 +/- 1.82 W/l) was greater (p = 0.0001) than fibers from normal palates (1.60 +/- 0.12 W/l). There are clear physiologic differences in single muscle fibers from cleft palates and normal palates: cleft palate fibers are physiologically fast, have greater fatigability, and have greater power production. Detection of functional and/or fiber type differences in muscles of cleft palates may provide preoperative identification of a patient's susceptibility to velopharyngeal inadequacy and permit early surgical intervention to correct this clinical condition.

Neural and Muscular Contributions to the Age-Related Reductions in Rapid Strength.

PubMed

Gerstner, Gena R; Thompson, Brennan J; Rosenberg, Joseph G; Sobolewski, Eric J; Scharville, Michael J; Ryan, Eric D

2017-07-01

The purposes of this study were to investigate the age-related differences in absolute and normalized plantarflexion rate of torque development (RTD) at early (0-50 ms) and late (100-200 ms) time intervals and to examine specific neural and muscular mechanisms contributing to these differences. Thirty-two young (20.0 ± 2.1 yr) and 20 older (69.5 ± 3.3 yr) recreationally active men performed rapid plantarflexion isometric muscle actions to examine absolute and normalized RTD and muscle activation using EMG at early and late time intervals. Ultrasonography was used to examine medial gastrocnemius muscle size, echo intensity (EI), and muscle architecture (fascicle length [FL] and pennation angle [PA]). The older men were weaker (23.9%, P < 0.001) and had lower later absolute and normalized RTD (P = 0.001-0.034) variables when compared with the young men. The older men also had higher EI (P < 0.001), smaller PA (P = 0.004), and lower later EMG amplitude values (P = 0.009-0.046). However, there were no differences in early RTD and EMG amplitude values, muscle size, or FL between groups (P = 0.097-0.914). Lower late RTD values were related to higher EI, smaller PA, and lower EMG amplitude values (r = -0.28-0.59, P = 0.001-0.044); however, late RTD values were no longer related to PA after normalizing to peak torque. Age-related alterations in muscle quality (EI), architecture, and muscle activation may influence rapid torque production at late time intervals (≥100 ms) from contraction onset. These findings highlight specific neuromuscular factors that influence the age-related reductions in RTD, which has been shown to significantly influence function and performance in older adults.

Intermittent whole-body vibration attenuates a reduction in the number of the capillaries in unloaded rat skeletal muscle.

PubMed

Kaneguchi, Akinori; Ozawa, Junya; Kawamata, Seiichi; Kurose, Tomoyuki; Yamaoka, Kaoru

2014-09-26

Whole-body vibration has been suggested for the prevention of muscle mass loss and muscle wasting as an attractive measure for disuse atrophy. This study examined the effects of daily intermittent whole-body vibration and weight bearing during hindlimb suspension on capillary number and muscle atrophy in rat skeletal muscles. Sixty male Wistar rats were randomly divided into four groups: control (CONT), hindlimb suspension (HS), HS + weight bearing (WB), and HS + whole-body vibration (VIB) (n = 15 each). Hindlimb suspension was applied for 2 weeks in HS, HS + WB, and HS + VIB groups. During suspension, rats in HS + VIB group were placed daily on a vibrating whole-body vibration platform for 20 min. In HS + WB group, suspension was interrupted for 20 min/day, allowing weight bearing. Untreated rats were used as controls. Soleus muscle wet weights and muscle fiber cross-sectional areas (CSA) significantly decreased in HS, HS + WB, and HS + VIB groups compared with CONT group. Both muscle weights and CSA were significantly greater in HS + WB and HS + VIB groups compared with HS group. Capillary numbers (represented by capillary-to-muscle fiber ratio) were significantly smaller in all hindlimb suspension-treated groups compared with CONT group. However, a reduction in capillary number by unloading hindlimbs was partially prevented by whole-body vibration. These findings were supported by examining mRNA for angiogenic-related factors. Expression levels of a pro-angiogenic factor, vascular endothelial growth factor-A mRNA, were significantly lower in all hindlimb suspension-treated groups compared with CONT group. There were no differences among hindlimb suspension-treated groups. Expression levels of an anti-angiogenic factor, CD36 (receptor for thrombospondin-1) mRNA, were significantly higher in all hindlimb suspension-treated groups compared with CONT group. Among the hindlimb suspension-treated groups, expression of CD36 mRNA in HS + VIB group tended to be suppressed (less than half the HS group). Our results suggest that weight bearing with or without vibration is effective for disuse-derived disturbance by preventing muscle atrophy, and whole-body vibration exercise has an additional benefit of maintaining microcirculation of skeletal muscle.

[The effects of hippophae juice on free radical metabolism of rat skeletal muscle and the content of Hb, Ck, T in blood].

PubMed

Qiao, Xiu-Fang; Pan, Hong-Ying

2010-08-01

To explore the effects of hippophae juice on free radical metabolism of rat skeletal muscle and partial biomarkers in blood. Randomly dividing the 30 SD rats into 3 groups (n = 10): sedentary group, training group and hippophae training group. Measuring related indices of skeletal muscle and blood in rat after 6 week training and hippophae juice supplement. Compared with training group, hippophae training group showed obviously longer exhaustive time, significantly increased antioxidant enzyme in skeletal muscle, remarkably decreased malonaldehyde (MDA) content in skeletal muscle, obviously increased testosterone (T) and hemoglobin (Hb) content in blood, significantly decreased creatine kinase (CK). Hippophae juice can impove the antioxidant ability of rat skeletal muscle, the level of T and Hb in blood, delay fatigue, therefore effectively enhance the aerobic stamina of rat.

On the efficiency of FES cycling: a framework and systematic review.

PubMed

Hunt, K J; Fang, J; Saengsuwan, J; Grob, M; Laubacher, M

2012-01-01

Research and development in the art of cycling using functional electrical stimulation (FES) of the paralysed leg muscles has been going on for around thirty years. A range of physiological benefits has been observed in clinical studies but an outstanding problem with FES-cycling is that efficiency and power output are very low. The present work had the following aims: (i) to provide a tutorial introduction to a novel framework and methods of estimation of metabolic efficiency using example data sets, and to propose benchmark measures for evaluating FES-cycling performance; (ii) to systematically review the literature pertaining specifically to the metabolic efficiency of FES-cycling, to analyse the observations and possible explanations for the low efficiency, and to pose hypotheses for future studies which aim to improve performance. We recommend the following as benchmark measures for assessment of the performance of FES-cycling: (i) total work efficiency, delta efficiency and stimulation cost; (ii) we recommend, further, that these benchmark measures be complemented by mechanical measures of maximum power output, sustainable steady-state power output and endurance. Performance assessments should be carried out at a well-defined operating point, i.e. under conditions of well controlled work rate and cadence, because these variables have a strong effect on energy expenditure. Future work should focus on the two main factors which affect FES-cycling performance, namely: (i) unfavourable biomechanics, i.e. crude recruitment of muscle groups, non-optimal timing of muscle activation, and lack of synergistic and antagonistic joint control; (ii) non-physiological recruitment of muscle fibres, i.e. mixed recruitment of fibres of different type and deterministic constant-frequency stimulation. We hypothesise that the following areas may bring better FES-cycling performance: (i) study of alternative stimulation strategies for muscle activation including irregular stimulation patterns (e.g. doublets, triplets, stochastic patterns) and variable frequency stimulation trains, where it appears that increasing frequency over time may be profitable; (ii) study of better timing parameters for the stimulated muscle groups, and addition of more muscle groups: this path may be approached using EMG studies and constrained numerical optimisation employing dynamic models; (iii) development of optimal stimulation protocols for muscle reconditioning and FES-cycle training.

Activity of metabolic enzymes and muscle-specific gene expression in parr and smolts Atlantic salmon Salmo salar L. of different age groups.

PubMed

Churova, Maria V; Meshcheryakova, Olga V; Veselov, Aleksey E; Efremov, Denis A; Nemova, Nina N

2017-08-01

This study was conducted to characterize the energy metabolism level and the features of muscle growth regulation during the development of Atlantic salmon (Salmo salar) inhabiting the Indera River (Kola Peninsula, Russia). The activities of aerobic and anaerobic enzymes (cytochrome c oxidase and lactate dehydrogenase) and carbohydrate metabolism enzymes (glucose-6-phosphate dehydrogenase, glycerol-3-phosphate dehydrogenase, and aldolase) were measured in muscle and liver tissue. Gene expression levels of myosin heavy chain (MyHC), myostatin (MSTN-1a), and myogenic regulatory factors (MRFs-MyoD1a, MyoD1b, MyoD1c, Myf5, myogenin) were measured in the white muscles of salmon parr of ages 0+, 1+, 2+, and 3+ and smolts of ages 2+ and 3+. Multidirectional changes in the activity of enzymes involved in aerobic and anaerobic energy metabolism with age were shown in the white muscles of the parr. The cytochrome c oxidase activity was higher in muscles of underyearlings (0+) and yearlings (1+) and decreased in 2+ and 3+ age groups. The activity of lactate dehydrogenase, in contrast, increased with age. The patterns of changes in expression levels of MyoD1a, MyoD1b, myogenin, MyHC, and MSTN-1a at different ages of the parr were similar. Particularly, the expression of these genes peaked in the yearling parr (1+) and then decreased in elder groups. The differences were revealed in parameters studied between the parr and smolts. The level of aerobic and anaerobic metabolism enzyme activities was higher in the white muscles of smolts than in parr. The activity of carbohydrate metabolism enzymes was decreased in the smolts' livers. The expression levels of MyHC, MyoD1a, MyoD1b, and myogenin were lower in smolts at age 2+ compared to parr. These findings expand our knowledge of age-related and stage-related features of energy metabolism and muscle development regulation in young Atlantic salmon in their natural habitat. The results might be used for monitoring of the salmon population during restoration and rearing.

Effects of integrated treatment with LED and microcurrent on muscle tone and stiffness in the calf muscle during moderate aerobic exercise.

PubMed

Han, Sang-Wan; Lee, Jeong-Woo

2018-06-01

[Purpose] This study aimed to investigate the effects of the therapeutic device combined with LED and microcurrent (MC) on muscle tone and stiffness in the calf muscle after its application during moderate aerobic exercise. [Subjects and Methods] Twenty healthy adult subjects were randomized to either the test group of the therapeutic device combined with LED and MC or the control group, and they walked on a 10%-sloped treadmill with a 5 km/hr speed for 30 minutes. Each of the subjects in the test group performed treadmill exercise with the therapeutic device attached to the edge of his or her calf muscle. After the exercise, the muscle tone and stiffness at the edge of the calf muscle were measured. [Results] With respect to the muscle tone, a statistically significant difference was found between the two groups only 5 minutes after the exercise. Concerning muscle stiffness, significant differences were shown between the two groups right after the exercise and 5 minutes after the exercise. [Conclusion] Integrated treatment with LED and MC on is considered helpful for lowering the muscle tone 5 minutes after the exercise, and for lowering the muscle stiffness right after the exercise and 5 minutes after the exercise.

Tetracycline-inducible system for regulation of skeletal muscle-specific gene expression in transgenic mice

NASA Technical Reports Server (NTRS)

Grill, Mischala A.; Bales, Mark A.; Fought, Amber N.; Rosburg, Kristopher C.; Munger, Stephanie J.; Antin, Parker B.

2003-01-01

Tightly regulated control of over-expression is often necessary to study one aspect or time point of gene function and, in transgenesis, may help to avoid lethal effects and complications caused by ubiquitous over-expression. We have utilized the benefits of an optimized tet-on system and a modified muscle creatine kinase (MCK) promoter to generate a skeletal muscle-specific, doxycycline (Dox) controlled over-expression system in transgenic mice. A DNA construct was generated in which the codon optimized reverse tetracycline transactivator (rtTA) was placed under control of a skeletal muscle-specific version of the mouse MCK promoter. Transgenic mice containing this construct expressed rtTA almost exclusively in skeletal muscles. These mice were crossed to a second transgenic line containing a bi-directional promoter centered on a tet responder element driving both a luciferase reporter gene and a tagged gene of interest; in this case the calpain inhibitor calpastatin. Compound hemizygous mice showed high level, Dox dependent muscle-specific luciferase activity often exceeding 10,000-fold over non-muscle tissues of the same mouse. Western and immunocytochemical analysis demonstrated similar Dox dependent muscle-specific induction of the tagged calpastatin protein. These findings demonstrate the effectiveness and flexibility of the tet-on system to provide a tightly regulated over-expression system in adult skeletal muscle. The MCKrtTA transgenic lines can be combined with other transgenic responder lines for skeletal muscle-specific over-expression of any target gene of interest.

Effect of shoulder girdle strengthening on trunk alignment in patients with stroke.

PubMed

Awad, Amina; Shaker, Hussien; Shendy, Wael; Fahmy, Manal

2015-07-01

[Purpose] This study investigated the effect of shoulder girdle strengthening, particularly the scapular muscles, on poststroke trunk alignment. [Subjects and Methods] The study involved 30 patients with residual hemiparesis following cerebrovascular stroke. Patient assessment included measuring shoulder muscle peak torque, scapular muscles peak force, spinal lateral deviation angle, and motor functional performance. Patients were randomly allocated either to the control group or the study group and received an 18-session strengthening program including active resisted exercises for shoulder abductors and external rotators in addition to trunk control exercises. The study group received additional strengthening exercises for the scapular muscles. [Results] The two groups showed significant improvement in strength of all shoulder and scapular muscles, with higher improvement in the study group. Similarly, the lateral spinal deviation angles significantly improved in both groups, with significantly higher improvement in the study group. Transfer activity, sitting balance, upper limb functions, and hand movements significantly improved in the two groups, with higher improvement in the latter two functions in the study group. [Conclusion] Strengthening of shoulder girdle muscles, particularly scapular muscles, can significantly contribute to improving the postural alignment of the trunk in patients with poststroke hemiparesis.

Kicking modality during erratic-dynamic and static condition effects the muscular co-activation of attacker.

PubMed

Kim, Tae-Whan; Lee, Sang-Cheol; Kil, Se-Kee; Kang, Sung-Chul; Lim, Young-Tae; Kim, Ki-Tae; Panday, Siddhartha Bikram

2017-05-01

The purpose of the study was to investigate the effect of different kicking modality, i.e., erratic-dynamic target (EDT) versus static target (ST) on the performance of the roundhouse kick in two groups of taekwondo athletes of different skill level. Three-dimensional analysis and surface electromyography (SEMG) analysis were performed on 12 (Group A: six sub-elite, Group B: six elite) athletes to investigate muscle co-activation pattern under two conditions, i.e., EDT versus ST. In the results, the muscle recruitment ratio of the agonistic muscles was higher for Group A, whereas Group B had higher recruitment ratio for antagonist muscles. Overall, the co-activation index (CI) of hip joints appeared higher in the extensors for Group A, whereas higher CI was observed in flexor muscles for Group B with comparatively higher CI during EDT condition than ST condition. Higher value of CI was observed in flexor muscles of the knee joints among Group A during EDT conditions, in contrast, higher CI in the extensor muscles was observed among Group B during ST conditions. In conclusion, the study confirmed that erratic-dynamic movements of target could change the movement coordination pattern to maintain the joint stability of participants.

Muscle-specific kinase-antibody-positive myasthenia gravis after autologous bone marrow transplantation.

PubMed

Grover, Kavita Mohindra; Sripathi, Naganand; Elias, Stanton Bernard

2012-03-01

A 44-year-old man presented with oculobulbar weakness approximately 5 years after autologous bone marrow transplantation (BMT). His workup led to the diagnosis of muscle-specific kinase-antibody-related myasthenia gravis (MG). There has been only one case report of muscle-specific kinase-antibody-positive MG after BMT, which was allogeneic. We report the first case of autologous BMT-associated MG with muscle-specific kinase antibody. The pathogenic mechanisms of immune dysregulation leading to MG after BMT are discussed.

Muscle mass and composition of the hip, thigh and abdominal muscles in women with and without hip osteoarthritis.

PubMed

Fukumoto, Yoshihiro; Ikezoe, Tome; Tateuchi, Hiroshige; Tsukagoshi, Rui; Akiyama, Haruhiko; So, Kazutaka; Kuroda, Yutaka; Yoneyama, Tomohide; Ichihashi, Noriaki

2012-09-01

The objective of this study was to compare muscle mass and composition between individuals with and without hip osteoarthritis. Twenty-four women with hip osteoarthritis (OA group) and 16 healthy women (healthy group) participated in this study. Muscle thickness (MT) and echo intensity (EI) were measured as indices of muscle mass and composition, respectively, using ultrasound imaging. Seven muscles were examined: gluteus maximus, gluteus medius, quadriceps femoris, rectus abdominis, external oblique, internal oblique and transversus abdominis. MT of only quadriceps femoris in the OA group was significantly thinner than that in the healthy group. EIs of gluteus medius, quadriceps femoris and rectus abdominis were significantly higher in the OA group than those in the healthy group. Thus, actual contractile tissue of gluteus medius and rectus abdominis substantially decreased, although muscle mass was similar, whereas both quantitative and qualitative changes occurred in quadriceps femoris in patients with hip OA. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

A Randomized Trial on the Effect of Bone Tissue on Vibration-induced Muscle Strength Gain and Vibration-induced Reflex Muscle Activity

PubMed Central

Cidem, Muharrem; Karacan, İlhan; Diraçoğlu, Demirhan; Yıldız, Aysel; Küçük, Suat Hayri; Uludağ, Murat; Gün, Kerem; Özkaya, Murat; Karamehmetoğlu, Şafak Sahir

2014-01-01

Background: Whole-body vibration (WBV) induces reflex muscle activity and leads to increased muscle strength. However, little is known about the physiological mechanisms underlying the effects of whole-body vibration on muscular performance. Tonic vibration reflex is the most commonly cited mechanism to explain the effects of whole-body vibration on muscular performance, although there is no conclusive evidence that tonic vibration reflex occurs. The bone myoregulation reflex is another neurological mechanism used to explain the effects of vibration on muscular performance. Bone myoregulation reflex is defined as a reflex mechanism in which osteocytes exposed to cyclic mechanical loading induce muscle activity. Aims: The aim of this study was to assess whether bone tissue affected vibration-induced reflex muscle activity and vibration-induced muscle strength gain. Study Design: A prospective, randomised, controlled, double-blind, parallel-group clinical trial. Methods: Thirty-four participants were randomised into two groups. High-magnitude whole-body vibration was applied in the exercise group, whereas low-magnitude whole-body vibration exercises were applied in the control group throughout 20 sessions. Hip bone mineral density, isokinetic muscle strength, and plasma sclerostin levels were measured. The surface electromyography data were processed to obtain the Root Mean Squares, which were normalised by maximal voluntarily contraction. Results: In the exercise group, muscle strength increased in the right and left knee flexors (23.9%, p=0.004 and 27.5%, p<0.0001, respectively). However, no significant change was observed in the knee extensor muscle strength. There was no significant change in the knee muscle strength in the control group. The vibration-induced corrected Root Mean Squares of the semitendinosus muscle was decreased by 2.8 times (p=0.005) in the exercise group, whereas there was no change in the control group. Sclerostin index was decreased by 15.2% (p=0.031) in the exercise group and increased by 20.8% (p=0.028) in the control group. A change in the sclerostin index was an important predictor of a change in the vibration-induced normalised Root Mean Square of the semitendinosus muscle (R2=0.7, p=0.0001). Femoral neck bone mineral density was an important predictor of muscle strength gain (R2=0.26, p=0.035). Conclusion: This study indicates that bone tissue may have an effect on vibration-induced muscle strength gain and vibration-induced reflex muscle activity. Trial registration: ClinicalTrials.gov: NCT01310348. PMID:25207162

A Randomized Trial on the Effect of Bone Tissue on Vibration-induced Muscle Strength Gain and Vibration-induced Reflex Muscle Activity.

PubMed

Cidem, Muharrem; Karacan, Ilhan; Diraçoğlu, Demirhan; Yıldız, Aysel; Küçük, Suat Hayri; Uludağ, Murat; Gün, Kerem; Ozkaya, Murat; Karamehmetoğlu, Safak Sahir

2014-03-01

Whole-body vibration (WBV) induces reflex muscle activity and leads to increased muscle strength. However, little is known about the physiological mechanisms underlying the effects of whole-body vibration on muscular performance. Tonic vibration reflex is the most commonly cited mechanism to explain the effects of whole-body vibration on muscular performance, although there is no conclusive evidence that tonic vibration reflex occurs. The bone myoregulation reflex is another neurological mechanism used to explain the effects of vibration on muscular performance. Bone myoregulation reflex is defined as a reflex mechanism in which osteocytes exposed to cyclic mechanical loading induce muscle activity. The aim of this study was to assess whether bone tissue affected vibration-induced reflex muscle activity and vibration-induced muscle strength gain. A prospective, randomised, controlled, double-blind, parallel-group clinical trial. Thirty-four participants were randomised into two groups. High-magnitude whole-body vibration was applied in the exercise group, whereas low-magnitude whole-body vibration exercises were applied in the control group throughout 20 sessions. Hip bone mineral density, isokinetic muscle strength, and plasma sclerostin levels were measured. The surface electromyography data were processed to obtain the Root Mean Squares, which were normalised by maximal voluntarily contraction. In the exercise group, muscle strength increased in the right and left knee flexors (23.9%, p=0.004 and 27.5%, p<0.0001, respectively). However, no significant change was observed in the knee extensor muscle strength. There was no significant change in the knee muscle strength in the control group. The vibration-induced corrected Root Mean Squares of the semitendinosus muscle was decreased by 2.8 times (p=0.005) in the exercise group, whereas there was no change in the control group. Sclerostin index was decreased by 15.2% (p=0.031) in the exercise group and increased by 20.8% (p=0.028) in the control group. A change in the sclerostin index was an important predictor of a change in the vibration-induced normalised Root Mean Square of the semitendinosus muscle (R2=0.7, p=0.0001). Femoral neck bone mineral density was an important predictor of muscle strength gain (R2=0.26, p=0.035). This study indicates that bone tissue may have an effect on vibration-induced muscle strength gain and vibration-induced reflex muscle activity. ClinicalTrials.gov: NCT01310348.

Does pelvic floor muscle training abolish symptoms of urinary incontinence? A randomized controlled trial.

PubMed

Celiker Tosun, O; Kaya Mutlu, E; Ergenoglu, A M; Yeniel, A O; Tosun, G; Malkoc, M; Askar, N; Itil, I M

2015-06-01

To determine whether symptoms of urinary incontinence is reduced by pelvic floor muscle training, to determine whether urinary incontinence can be totally eliminated by strengthening the pelvic floor muscle to grade 5 on the Oxford scale. Prospective randomized controlled clinical trial. Outpatient urogynecology department. One hundred thirty cases with stress and mixed urinary incontinence. All participants were randomly allocated to the pelvic floor muscle training group or control group. A 12-week home based exercise program, prescribed individually, was performed by the pelvic floor muscle training group. Urinary incontinence symptoms (Incontinence Impact Questionnaire-7, Urogenital Distress Inventory-6, bladder diary, stop test and pad test) were assessed, and the pelvic floor muscle strength was measured for (PERFECT testing, perineometric and ultrasound) all participants before and after 12 weeks of treatment. The pelvic floor muscle training group had significant improvement in their symptoms of urinary incontinence (P=0.001) and an increase in pelvic floor muscle strength (P=0.001, by the dependent t test) compared with the control group. All the symptoms of urinary incontinence were significantly decreased in the patients that had reached pelvic floor muscle strength of grade 5 and continued the pelvic floor muscle training (P<0.05). The study demonstrated that pelvic floor muscle training is effective in reducing the symptoms of stress and mixed urinary incontinence and in increasing pelvic floor muscle strength. © The Author(s) 2014.

Developing a musculoskeletal model of the primate skull: predicting muscle activations, bite force, and joint reaction forces using multibody dynamics analysis and advanced optimisation methods.

PubMed

Shi, Junfen; Curtis, Neil; Fitton, Laura C; O'Higgins, Paul; Fagan, Michael J

2012-10-07

An accurate, dynamic, functional model of the skull that can be used to predict muscle forces, bite forces, and joint reaction forces would have many uses across a broad range of disciplines. One major issue however with musculoskeletal analyses is that of muscle activation pattern indeterminacy. A very large number of possible muscle force combinations will satisfy a particular functional task. This makes predicting physiological muscle recruitment patterns difficult. Here we describe in detail the process of development of a complex multibody computer model of a primate skull (Macaca fascicularis), that aims to predict muscle recruitment patterns during biting. Using optimisation criteria based on minimisation of muscle stress we predict working to balancing side muscle force ratios, peak bite forces, and joint reaction forces during unilateral biting. Validation of such models is problematic; however we have shown comparable working to balancing muscle activity and TMJ reaction ratios during biting to those observed in vivo and that peak predicted bite forces compare well to published experimental data. To our knowledge the complexity of the musculoskeletal model is greater than any previously reported for a primate. This complexity, when compared to more simple representations provides more nuanced insights into the functioning of masticatory muscles. Thus, we have shown muscle activity to vary throughout individual muscle groups, which enables them to function optimally during specific masticatory tasks. This model will be utilised in future studies into the functioning of the masticatory apparatus. Copyright © 2012 Elsevier Ltd. All rights reserved.

Low-Level Laser Therapy (LLLT) in Dystrophin-Deficient Muscle Cells: Effects on Regeneration Capacity, Inflammation Response and Oxidative Stress.

PubMed

Macedo, Aline Barbosa; Moraes, Luis Henrique Rapucci; Mizobuti, Daniela Sayuri; Fogaça, Aline Reis; Moraes, Fernanda Dos Santos Rapucci; Hermes, Tulio de Almeida; Pertille, Adriana; Minatel, Elaine

2015-01-01

The present study evaluated low-level laser therapy (LLLT) effects on some physiological pathways that may lead to muscle damage or regeneration capacity in dystrophin-deficient muscle cells of mdx mice, the experimental model of Duchenne muscular dystrophy (DMD). Primary cultures of mdx skeletal muscle cells were irradiated only one time with laser and analyzed after 24 and 48 hours. The LLLT parameter used was 830 nm wavelengths at 5 J/cm² fluence. The following groups were set up: Ctrl (untreated C57BL/10 primary muscle cells), mdx (untreated mdx primary muscle cells), mdx LA 24 (mdx primary muscle cells - LLLT irradiated and analyzed after 24 h), and mdx LA 48 (mdx primary muscle cells - LLLT irradiated and analyzed after 48 h). The mdx LA 24 and mdx LA 48 groups showed significant increase in cell proliferation, higher diameter in muscle cells and decreased MyoD levels compared to the mdx group. The mdx LA 48 group showed significant increase in Myosin Heavy Chain levels compared to the untreated mdx and mdx LA 24 groups. The mdx LA 24 and mdx LA 48 groups showed significant increase in [Ca2+]i. The mdx group showed significant increase in H2O2 production and 4-HNE levels compared to the Ctrl group and LLLT treatment reduced this increase. GSH levels and GPx, GR and SOD activities increased in the mdx group. Laser treatment reduced the GSH levels and GR and SOD activities in dystrophic muscle cells. The mdx group showed significant increase in the TNF-α and NF-κB levels, which in turn was reduced by the LLLT treatment. Together, these results suggest that the laser treatment improved regenerative capacity and decreased inflammatory response and oxidative stress in dystrophic muscle cells, indicating that LLLT could be a helpful alternative therapy to be associated with other treatment for dystrophinopathies.

A pelvic floor muscle training program in postmenopausal women: A randomized controlled trial.

PubMed

Alves, Fabíola K; Riccetto, Cássio; Adami, Délcia B V; Marques, Joseane; Pereira, Larissa C; Palma, Paulo; Botelho, Simone

2015-06-01

The purpose of this study was to investigate if a specific pelvic floor muscle training (PFMT) program effectively increases pelvic floor muscle (PFM) contractility and decreases anterior pelvic organ prolapse (POP) as well as urogynecological symptoms, in postmenopausal women. The mean outcome measure of this study was the pelvic floor surface electromyography (sEMG) activity. A clinical, randomized, blinded-assessor and controlled study was conducted with 46 postmenopausal women. Thirty women completed this study (mean age of 65.93 years), divided into two groups: Treatment Group - TG (n=18) and Control Group - CG (n=12). The evaluation was carried out using digital palpation, sEMG, pelvic organ prolapse quantification (POP-Q) as well as validated questionnaires by the International Consultation on Incontinence Questionnaires to investigate urogynecological symptoms. The treatment protocol consisted of 12 group sessions, twice a week, with 30 min of duration each. These data were then submitted to statistical analyses by the Statistical Analysis System for Windows software, with a significance level of 5%. The pelvic floor muscle contractility increased after PFMT, evaluated by sEMG (p=0.003) and digital palpation (p=0.001), accompanied by a decrease in urinary symptoms (p<0.001 for ICIQ-OAB scores e 0.036 for ICIQ UI-SF) as well as anterior pelvic organ prolapse (p=0.03). This preliminary study suggests that the applied PFMT program could be an effective way to increase PFM contractility, as well as to decrease both anterior pelvic organ prolapse and urinary symptoms, in postmenopausal women. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

High spatial resolution pressure distribution of the vaginal canal in Pompoir practitioners: A biomechanical approach for assessing the pelvic floor.

PubMed

Cacciari, Licia P; Pássaro, Anice C; Amorim, Amanda C; Sacco, Isabel C N

2017-08-01

Pompoir is a technique poorly studied in the literature that claims to improve pelvic floor strength and coordination. This study aims to investigate the pelvic floor muscles' coordination throughout the vaginal canal among Pompoir practitioners and non-practitioners by describing a high resolution map of pressure distribution. This cross-sectional, study included 40 healthy women in two groups: control and Pompoir. While these women performed both sustained and "waveform" pelvic floor muscle contractions, the spatiotemporal pressure distribution in their vaginal canals was evaluated by a non-deformable probe fully instrumented with a 10×10 matrix of capacitive transducers. Pompoir group was able to sustain the pressure levels achieved for a longer period (40% longer, moderate effect, P=0.04). During the "waveform" contraction task, Pompoir group achieved lower, earlier peak pressures (moderate effect, P=0.05) and decreased rates of contraction (small effect, P=0.04) and relaxation (large effect, P=0.01). During both tasks, Pompoir group had smaller relative contributions by the mid-region and the anteroposterior planes and greater contributions by the caudal and cranial regions and the latero-lateral planes. Results suggest that specific coordination training of the pelvic floor muscles alters the pressure distribution profile, promoting a more-symmetric distribution of pressure throughout the vaginal canal. Therefore, this study suggests that pelvic floor muscles can be trained to a degree beyond strengthening by focusing on coordination, which results in changes in symmetry of the spatiotemporal pressure distribution in the vaginal canal. Copyright © 2017 Elsevier Ltd. All rights reserved.

Growth hormone therapy, muscle thickness, and motor development in Prader-Willi syndrome: an RCT.

PubMed

Reus, Linda; Pillen, Sigrid; Pelzer, Ben J; van Alfen-van der Velden, Janielle A A E M; Hokken-Koelega, Anita C S; Zwarts, Machiel; Otten, Barto J; Nijhuis-van der Sanden, Maria W G

2014-12-01

To investigate the effect of physical training combined with growth hormone (GH) on muscle thickness and its relationship with muscle strength and motor development in infants with Prader-Willi syndrome (PWS). In a randomized controlled trial, 22 infants with PWS (12.9 ± 7.1 months) were followed over 2 years to compare a treatment group (n = 10) with a waiting-list control group (n = 12). Muscle thickness of 4 muscle groups was measured by using ultrasound. Muscle strength was evaluated by using the Infant Muscle Strength meter. Motor performance was measured with the Gross Motor Function Measurement. Analyses of variance were used to evaluate between-group effects of GH on muscle thickness at 6 months and to compare pre- and posttreatment (after 12 months of GH) values. Multilevel analyses were used to evaluate effects of GH on muscle thickness over time, and multilevel bivariate analyses were used to test relationships between muscle thickness, muscle strength, and motor performance. A significant positive effect of GH on muscle thickness (P < .05) was found. Positive relationships were found between muscle thickness and muscle strength (r = 0.61, P < .001), muscle thickness and motor performance (r = 0.81, P < .001), and muscle strength and motor performance (r = 0.76, P < .001). GH increased muscle thickness, which was related to muscle strength and motor development in infants with PWS. Catch-up growth was faster in muscles that are most frequently used in early development. Because this effect was independent of GH, it suggests a training effect. Copyright © 2014 by the American Academy of Pediatrics.

Time-Course of Muscle Mass Loss, Damage, and Proteolysis in Gastrocnemius following Unloading and Reloading: Implications in Chronic Diseases

PubMed Central

Chacon-Cabrera, Alba; Lund-Palau, Helena; Gea, Joaquim; Barreiro, Esther

2016-01-01

Background Disuse muscle atrophy is a major comorbidity in patients with chronic diseases including cancer. We sought to explore the kinetics of molecular mechanisms shown to be involved in muscle mass loss throughout time in a mouse model of disuse muscle atrophy and recovery following immobilization. Methods Body and muscle weights, grip strength, muscle phenotype (fiber type composition and morphometry and muscle structural alterations), proteolysis, contractile proteins, systemic troponin I, and mitochondrial content were assessed in gastrocnemius of mice exposed to periods (1, 2, 3, 7, 15 and 30 days) of non-invasive hindlimb immobilization (plastic splint, I cohorts) and in those exposed to reloading for different time-points (1, 3, 7, 15, and 30 days, R cohorts) following a seven-day period of immobilization. Groups of control animals were also used. Results Compared to non-exposed controls, muscle weight, limb strength, slow- and fast-twitch cross-sectional areas, mtDNA/nDNA, and myosin content were decreased in mice of I cohorts, whereas tyrosine release, ubiquitin-proteasome activity, muscle injury and systemic troponin I levels were increased. Gastrocnemius reloading following splint removal improved muscle mass loss, strength, fiber atrophy, injury, myosin content, and mtDNA/nDNA, while reducing ubiquitin-proteasome activity and proteolysis. Conclusions A consistent program of molecular and cellular events leading to reduced gastrocnemius muscle mass and mitochondrial content and reduced strength, enhanced proteolysis, and injury, was seen in this non-invasive mouse model of disuse muscle atrophy. Unloading of the muscle following removal of the splint significantly improved the alterations seen during unloading, characterized by a specific kinetic profile of molecular events involved in muscle regeneration. These findings have implications in patients with chronic diseases including cancer in whom physical activity may be severely compromised. PMID:27792730

Sericin and swimming on histomorphometric parameters of denervated plantar muscle in Wistar rats.

PubMed

Santana, André Junior; Debastiani, Jean Carlos; Buratti, Pâmela; Peretti, Ana Luiza; Kunz, Regina Inês; Brancalhão, Rose Meire Costa; Ribeiro, Lucinéia de Fátima Chasko; Torrejais, Márcia Miranda; Bertolini, Gladson Ricardo Flor

2018-01-01

Objective To analyze the combined effects of the silk protein sericin and swimming exercise on histomorphometry of the plantar muscle in Wistar rats. Methods Forty adult rats were randomly allocated into 5 groups comprising 8 animals each, as follows: Control, Injury, Sericin, Swim, and Swim plus Sericin. Three days after crushing of the sciatic nerve the rats in the Swim and Swim plus Sericin Groups were submitted to swimming exercise for 21 days. Rats were then euthanized and the plantar muscle harvested and processed. Results Cross-sectional area, peripheral nuclei and muscle fiber counts, nucleus/fiber ratio and smallest muscle fiber width did not differ significantly between groups. Morphological analysis revealed hypertrophic fibers in the Swim Group and evident muscle damage in the Swim plus Sericin and Injury Groups. The percentage of intramuscular collagen was apparently maintained in the Swim Group compared to remaining groups. Conclusion Combined treatment with sericin and swimming exercise did not improve muscle properties. However, physical exercise alone was effective in maintaining intramuscular connective tissue and preventing progression of deleterious effects of peripheral nerve injury.

Aerobic exercise and respiratory muscle strength in patients with cystic fibrosis.

PubMed

Dassios, Theodore; Katelari, Anna; Doudounakis, Stavros; Dimitriou, Gabriel

2013-05-01

The beneficial role of exercise in maintaining health in patients with cystic fibrosis (CF) is well described. Few data exist on the effect of exercise on respiratory muscle function in patients with CF. Our objective was to compare respiratory muscle function indices in CF patients that regularly exercise with those CF patients that do not. This cross-sectional study assessed nutrition, pulmonary function and respiratory muscle function in 37 CF patients that undertook regular aerobic exercise and in a control group matched for age and gender which consisted of 44 CF patients that did not undertake regular exercise. Respiratory muscle function in CF was assessed by maximal inspiratory pressure (Pimax), maximal expiratory pressure (Pemax) and pressure-time index of the respiratory muscles (PTImus). Median Pimax and Pemax were significantly higher in the exercise group compared to the control group (92 vs. 63 cm H2O and 94 vs. 64 cm H2O respectively). PTImus was significantly lower in the exercise group compared to the control group (0.089 vs. 0.121). Upper arm muscle area (UAMA) and mid-arm muscle circumference were significantly increased in the exercise group compared to the control group (2608 vs. 2178 mm2 and 23 vs. 21 cm respectively). UAMA was significantly related to Pimax in the exercising group. These results suggest that CF patients that undertake regular aerobic exercise maintain higher indices of respiratory muscle strength and lower PTImus values, while increased UAMA values in exercising patients highlight the importance of muscular competence in respiratory muscle function in this population. Copyright © 2013 Elsevier Ltd. All rights reserved.

RNA sequencing identifies upregulated kyphoscoliosis peptidase and phosphatidic acid signaling pathways in muscle hypertrophy generated by transgenic expression of myostatin propeptide.

PubMed

Miao, Yuanxin; Yang, Jinzeng; Xu, Zhong; Jing, Lu; Zhao, Shuhong; Li, Xinyun

2015-04-09

Myostatin (MSTN), a member of the transforming growth factor-β superfamily, plays a crucial negative role in muscle growth. MSTN mutations or inhibitions can dramatically increase muscle mass in most mammal species. Previously, we generated a transgenic mouse model of muscle hypertrophy via the transgenic expression of the MSTN N-terminal propeptide cDNA under the control of the skeletal muscle-specific MLC1 promoter. Here, we compare the mRNA profiles between transgenic mice and wild-type littermate controls with a high-throughput RNA sequencing method. The results show that 132 genes were significantly differentially expressed between transgenic mice and wild-type control mice; 97 of these genes were up-regulated, and 35 genes were down-regulated in the skeletal muscle. Several genes that had not been reported to be involved in muscle hypertrophy were identified, including up-regulated myosin binding protein H (mybph), and zinc metallopeptidase STE24 (Zmpste24). In addition, kyphoscoliosis peptidase (Ky), which plays a vital role in muscle growth, was also up-regulated in the transgenic mice. Interestingly, a pathway analysis based on grouping the differentially expressed genes uncovered that cardiomyopathy-related pathways and phosphatidic acid (PA) pathways (Dgki, Dgkz, Plcd4) were up-regulated. Increased PA signaling may increase mTOR signaling, resulting in skeletal muscle growth. The findings of the RNA sequencing analysis help to understand the molecular mechanisms of muscle hypertrophy caused by MSTN inhibition.

An evaluation of upper-body muscle activation during coupled and uncoupled instability resistance training.

PubMed

Campbell, Brian M; Kutz, Matt R; Morgan, Amy L; Fullenkamp, Adam M; Ballenger, Ryan

2014-07-01

Recently, there has been a growth in the popularity of resistance exercises performed on unstable surfaces. However, the relationship between unstable surface training and load coupling on muscle activation is unclear. The purpose of this study was to evaluate changes in muscle activation during a barbell (BB) (coupled) and dumbbell (DB) (uncoupled) chest press exercise performed on an unstable surface. The 3 specific chest press conditions included 50% 1 repetition maximum (RM) with BB (50% BB), 50% 1RM with DBs (50% DB), and 25% 1RM with DBs (25% DB). Ten male subjects participated in the study (age, 23.9 ± 2.6 years; body weight, 82.8 ± 10.2 kg). During testing, mean electromyographic activity was assessed for pectoralis major (PM), triceps brachii, anterior deltoid (AD), and rectus abdominis (RA) and was presented as a percent change across the lifting conditions. It was observed that muscle activation increased by 15% in both the PM and RA from the 50% BB condition to the 50% DB condition. Also, the greatest percent difference in muscle activation between the 50 and 25% DB conditions occurred for PM and AD (+54% during 50% DB). These results suggest that demands on the core musculature to provide stability are increased with the use of DBs (uncoupled) as opposed to a BB (coupled). Where instability training provides a sufficient hypertrophy stimulus in prime mover muscle groups, there may be the added benefit of core stability training. Specifically, this type of training may benefit both untrained persons and those engaged in active rehabilitation.

Primary mesenchymal (nonangiomatous/nonlymphomatous) neoplasms occurring in the canine spleen: anatomic classification, immunohistochemistry, and mitotic activity correlated with patient survival.

PubMed

Spangler, W L; Culbertson, M R; Kass, P H

1994-01-01

Surgical submissions from canine splenectomy cases spanning a 3-year period (1988-1990) were evaluated. Eighty seven neoplasms of the spleen considered to be of nonangiomatous and nonlymphomatous origin were selected for morphologic classification, mitotic index determination, immunohistochemical analysis, and patient survival determination. In 76/87 cases, patient survival information was available, and the mitotic index was determined in 83/87 cases. Immunohistochemistry for selected antigens (vimentin, desmin, smooth muscle actin, myosin, and factor VIII-related antigen) was performed in 58/87 of the cases. Morphologic classification of these lesions in standard HE preparations yielded the following neoplastic groups: fibrosarcoma (19/87), undifferentiated sarcoma (19/87), leiomyosarcoma (14/87), osteosarcoma (8/87), mesenchymoma (7/87), myxosarcoma (6/87), histiocytic sarcoma (6/87), leiomyoma (3/87), lipoma-myelolipoma (2/87), liposarcoma (2/87), and malignant fibrous histiocytoma (1/87). A lack of distinct morphologic characteristics among many of the neoplasms that were classified as either fibrosarcoma, leiomyosarcoma, or undifferentiated sarcoma contrasted these groups with the relatively unambiguous features that distinguished the other sarcoma groups. Using immunohistochemical staining for muscle-specific antigens (desmin, smooth muscle actin, and myosin), specific staining often overlapped extensively within the neoplastic groups of fibrosarcomas, leiomyosarcomas, and undifferentiated sarcomas, suggesting either ambiguous morphologic findings or the possibility of a common histogenesis from smooth muscle trabeculae or a distinct population of splenic myofibroblasts. The biological behavior of all tumors examined could be placed into three categories of patient survival: (1) benign, noninvasive tumors (leiomyoma, lipoma) with prolonged survival intervals; (2) malignant tumors (fibrosarcoma, undifferentiated sarcoma, leiomyosarcoma, osteosarcoma, myxosarcoma, histiocytic sarcoma, and liposarcoma), showing severely truncated survival (median 4 months with 80-100% mortality after 12 months; and (3) intermediate survival periods (median 12 months with 50% 1 year survival) attributed to a single group of neoplasm, the mesenchymomas. The biological behavior of primary splenic nonangiomatous, nonlymphomatous sarcomas was most closely correlated with observed mitotic index. Splenic neoplasms of this type with a mitotic index < 9 showed significantly (P < 0.0001) longer survival intervals than those with an index > 9. With the exception of osteosarcoma, all anatomically defined tumor groups contained one or more specimens with a mitotic index < 9. The clinical prognosis given for splenic sarcomas should be modified according to the mitotic index as a predictive value for patient survival.

Muscle-Specific Overexpression of PGC-1α Does Not Augment Metabolic Improvements in Response to Exercise and Caloric Restriction.

PubMed

Wong, Kari E; Mikus, Catherine R; Slentz, Dorothy H; Seiler, Sarah E; DeBalsi, Karen L; Ilkayeva, Olga R; Crain, Karen I; Kinter, Michael T; Kien, C Lawrence; Stevens, Robert D; Muoio, Deborah M

2015-05-01

This study used mice with muscle-specific overexpression of PGC-1α, a transcriptional coactivator that promotes mitochondrial biogenesis, to determine whether increased oxidative potential facilitates metabolic improvements in response to lifestyle modification. MCK-PGC1α mice and nontransgenic (NT) littermates were fed a high-fat diet (HFD) for 10 weeks, followed by stepwise exposures to voluntary wheel running (HFD+Ex) and then 25% caloric restriction with exercise (Ex/CR), each for an additional 10 weeks with continued HFD. Running and CR improved weight and glucose control similarly in MCK-PGC1α and NT mice. Sedentary MCK-PGC1α mice were more susceptible to diet-induced glucose intolerance, and insulin action measured in isolated skeletal muscles remained lower in the transgenic compared with the NT group, even after Ex/CR. Comprehensive profiling of >200 metabolites and lipid intermediates revealed dramatic group-specific responses to the intervention but did not produce a lead candidate that tracked with changes in glucose tolerance irrespective of genotype. Instead, principal components analysis identified a chemically diverse metabolite cluster that correlated with multiple measures of insulin responsiveness. These findings challenge the notion that increased oxidative capacity defends whole-body energy homeostasis and suggest that the interplay between mitochondrial performance, lipotoxicity, and insulin action is more complex than previously proposed. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Biochemical and physical factors affecting discoloration characteristics of 19 bovine muscles.

PubMed

McKenna, D R; Mies, P D; Baird, B E; Pfeiffer, K D; Ellebracht, J W; Savell, J W

2005-08-01

Steaks from muscles (n=19 from nine beef carcasses) were evaluated over the course of retail display (0-, 1-, 2-, 3-, 4- or 5-d) for objective measures of discoloration (metmyoglobin, oxymyoglobin, L*-, a*-, and b*-values), reducing ability (metmyoglobin reductase activity (MRA), resistance to induced metmyoglobin formation (RIMF), and nitric oxide metmyoglobin reducing ability (NORA)), oxygen consumption rate (OCR), oxygen penetration depth, myoglobin content, oxidative rancidity, and pH. Muscles were grouped according to objective color measures of discoloration. M. longissimus lumborum, M. longissimus thoracis, M. semitendinosus, and M. tensor fasciae latae were grouped as "high" color stability muscles, M. semimembranosus, M. rectus femoris, and M. vastus lateralis were grouped as "moderate" color stability muscles, M. trapezius, M. gluteus medius, and M. latissimus dorsi were grouped as "intermediate" color stability muscles, M. triceps brachi - long head, M. biceps femoris, M. pectoralis profundus, M. adductor, M. triceps brachi - lateral head, and M. serratus ventralis were grouped as "low" color stability muscles, and M. supraspinatus, M. infraspinatus, and M. psoas major were grouped as "very low" color stability muscles. Generally, muscles of high color stability had high RIMF, nitric oxide reducing ability, and oxygen penetration depth and possessed low OCRs, myoglobin content, and oxidative rancidity. In contrast, muscles of low color stability had high MRA, OCRs, myoglobin content, and oxidative rancidity and low RIMF, NORA, and oxygen penetration depth. Data indicate that discoloration differences between muscles are related to the amount of reducing activity relative to the OCR.

Effects of voluntary wheel running on satellite cells in the rat plantaris muscle.

PubMed

Kurosaka, Mitsutoshi; Naito, Hisashi; Ogura, Yuji; Kojima, Atsushi; Goto, Katsumasa; Katamoto, Shizuo

2009-01-01

This study investigated the effects of voluntary wheel running on satellite cells in the rat plantaris muscle. Seventeen 5-week-old male Wistar rats were assigned to a control (n = 5) or training (n = 12) group. Each rat in the training group ran voluntarily in a running-wheel cage for 8 weeks. After the training period, the animals were anesthetized, and the plantaris muscles were removed, weighed, and analyzed immunohistochemically and biochemically. Although there were no significant differences in muscle weight or fiber area between the groups, the numbers of satellite cells and myonuclei per muscle fiber, percentage of satellite cells, and citrate synthase activity were significantly higher in the training group compared with the control group (p < 0.05). The percentage of satellite cells was also positively correlated with distance run in the training group (r = 0.61, p < 0.05). Voluntary running can induce an increase in the number of satellite cells without changing the mean fiber area in the rat plantaris muscle; this increase in satellite cell content is a function of distance run. Key pointsThere is no study about the effect of voluntary running on satellite cells in the rat plantaris muscle.Voluntary running training causes an increase of citrate synthase activity in the rat plantaris muscle but does not affect muscle weight and mean fiber area in the rat plantaris muscle.Voluntary running can induce an increase in the number of satellite cells without hypertrophy of the rat plantaris muscle.

Glucose uptake heterogeneity of the leg muscles is similar between patients with multiple sclerosis and healthy controls during walking.

PubMed

Kindred, John H; Ketelhut, Nathaniel B; Rudroff, Thorsten

2015-02-01

Difficulties in ambulation are one of the main problems reported by patients with multiple sclerosis. A previous study by our research group showed increased recruitment of muscle groups during walking, but the influence of skeletal muscle properties, such as muscle fiber activity, has not been fully elucidated. The purpose of this investigation was to use the novel method of calculating glucose uptake heterogeneity in the leg muscles of patients with multiple sclerosis and compare these results to healthy controls. Eight patients with multiple sclerosis (4 men) and 8 healthy controls (4 men) performed 15 min of treadmill walking at a comfortable self-selected speed following muscle strength tests. Participants were injected with ≈ 8 mCi of [(18)F]-fluorodeoxyglucose during walking after which positron emission tomography/computed tomography imaging was performed. No differences in muscle strength were detected between multiple sclerosis and control groups (P>0.27). Within the multiple sclerosis, group differences in muscle volume existed between the stronger and weaker legs in the vastus lateralis, semitendinosus, and semimembranosus (P<0.03). Glucose uptake heterogeneity between the groups was not different for any muscle group or individual muscle of the legs (P>0.16, P≥0.05). Patients with multiple sclerosis and healthy controls showed similar muscle fiber activity during walking. Interpretations of these results, with respect to our previous study, suggest that walking difficulties in patients with multiple sclerosis may be more associated with altered central nervous system motor patterns rather than alterations in skeletal muscle properties. Published by Elsevier Ltd.

Pelvic floor muscle exercise by biofeedback and electrical stimulation to reinforce the pelvic floor muscle after normal delivery.

PubMed

Lee, In Sook; Choi, Euy Soon

2006-12-01

This study was conducted to investigate the effectiveness of pelvic floor muscle exercise using biofeedback and electrical stimulation after normal delivery. The subjects of this study were 49 (experimental group: 25, control group: 24) postpartum women who passed 6 weeks after normal delivery without complication of pregnancy, delivery and postpartum. The experimental group was applied to the pelvic muscle enforcement program by biofeedback and electrical stimulation for 30 minutes per session, twice a week for 6 weeks, after then self-exercise of pelvic floor muscle was done 50-60 repetition per session, 3 times a day for 6 weeks. Maximum pressure of pelvic floor muscle contraction (MPPFMC), average pressure of pelvic floor muscle contraction (APPFMC), duration time of pelvic floor muscle contraction (DTPFMC) and the subjective lower urinary symptoms were measured by digital perineometer and Bristol Female Urinary Symptom Questionnaire and compared between two groups prior to trial, at the end of treatment and 6 weeks after treatment. The results of this study indicated that MPPFMC, APPFMC, DTPFMC were significantly increased and subjective lower urinary symptoms were significantly decreased after treatment in the experimental group than in the control group. This study suggested that the pelvic floor muscle exercise using biofeedback and electrical stimulation might be a safer and more effective program for reinforcing pelvic floor muscle after normal delivery.

MCAT elements and the TEF-1 family of transcription factors in muscle development and disease.

PubMed

Yoshida, Tadashi

2008-01-01

MCAT elements are located in the promoter-enhancer regions of cardiac, smooth, and skeletal muscle-specific genes including cardiac troponin T, beta-myosin heavy chain, smooth muscle alpha-actin, and skeletal alpha-actin, and play a key role in the regulation of these genes during muscle development and disease. The binding factors of MCAT elements are members of the transcriptional enhancer factor-1 (TEF-1) family. However, it has not been fully understood how these transcription factors confer cell-specific expression in muscle, because their expression patterns are relatively broad. Results of recent studies revealed multiple mechanisms whereby TEF-1 family members control MCAT element-dependent muscle-specific gene expression, including posttranslational modifications of TEF-1 family members, the presence of muscle-selective TEF-1 cofactors, and cell-selective control of TEF-1 accessibility to MCAT elements. In addition, of particular interest, recent studies regarding MCAT element-dependent transcription of the myocardin gene and the smooth muscle alpha-actin gene in muscle provide evidence for the transcriptional diversity among distinct cell types and subtypes. This article summarizes the role of MCAT elements and the TEF-1 family of transcription factors in muscle development and disease, and reviews recent progress in our understanding of the transcriptional regulatory mechanisms involved in MCAT element-dependent muscle-specific gene expression.

The use of real-time ultrasound imaging for biofeedback of lumbar multifidus muscle contraction in healthy subjects.

PubMed

Van, Khai; Hides, Julie A; Richardson, Carolyn A

2006-12-01

Randomized controlled trial. To determine if the provision of visual biofeedback using real-time ultrasound imaging enhances the ability to activate the multifidus muscle. Increasingly clinicians are using real-time ultrasound as a form of biofeedback when re-educating muscle activation. The effectiveness of this form of biofeedback for the multifidus muscle has not been reported. Healthy subjects were randomly divided into groups that received different forms of biofeedback. All subjects received clinical instruction on how to activate the multifidus muscle isometrically prior to testing and verbal feedback regarding the amount of multifidus contraction, which occurred during 10 repetitions (acquisition phase). In addition, 1 group received visual biofeedback (watched the multifidus muscle contract) using real-time ultrasound imaging. All subjects were reassessed a week later (retention phase). Subjects from both groups improved their voluntary contraction of the multifidus muscle in the acquisition phase (P<.001) and the ability to recruit the multifidus muscle differed between groups (P<.05), with subjects in the group that received visual ultrasound biofeedback achieving greater improvements. In addition, the group that received visual ultrasound biofeedback retained their improvement in performance from week 1 to week 2 (P>.90), whereas the performance of the other group decreased (P<.05). Real-time ultrasound imaging can be used to provide visual biofeedback and improve performance and retention in the ability to activate the multifidus muscle in healthy subjects.

Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men.

PubMed

Schoenfeld, Brad J; Ratamess, Nicholas A; Peterson, Mark D; Contreras, Bret; Sonmez, G T; Alvar, Brent A

2014-10-01

Regimented resistance training has been shown to promote marked increases in skeletal muscle mass. Although muscle hypertrophy can be attained through a wide range of resistance training programs, the principle of specificity, which states that adaptations are specific to the nature of the applied stimulus, dictates that some programs will promote greater hypertrophy than others. Research is lacking, however, as to the best combination of variables required to maximize hypertophic gains. The purpose of this study was to investigate muscular adaptations to a volume-equated bodybuilding-type training program vs. a powerlifting-type routine in well-trained subjects. Seventeen young men were randomly assigned to either a hypertrophy-type resistance training group that performed 3 sets of 10 repetition maximum (RM) with 90 seconds rest or a strength-type resistance training (ST) group that performed 7 sets of 3RM with a 3-minute rest interval. After 8 weeks, no significant differences were noted in muscle thickness of the biceps brachii. Significant strength differences were found in favor of ST for the 1RM bench press, and a trend was found for greater increases in the 1RM squat. In conclusion, this study showed that both bodybuilding- and powerlifting-type training promote similar increases in muscular size, but powerlifting-type training is superior for enhancing maximal strength.

Physiotherapy treatment of the diabetic shoulder: a longitudinal study following patients with diabetes and shoulder pain using a pre-post treatment design.

PubMed

Kyhlbäck, Maria; Schröder Winter, Helena; Thierfelder, Tomas; Söderlund, Anne

2014-01-01

The aim of this study was to describe and evaluate a physiotherapy program targeted to reduce pain intensity and improve the daily functioning of diabetics with shoulder problems. It was hypothesized that patients receiving specific physiotherapy treatment improved more frequently and rapidly than diabetic patients followed up without specific physiotherapeutic intervention. A pre-post treatment design was completed for a group of 10 subjects. The treatment protocol, also applied during the daily activities of the subjects, was aiming at reducing pain intensity and shoulder stiffness and improving impaired functioning in daily activities by muscle relaxation, light-load exercise and enhancing proper shoulder co-ordination. The group analysis showed significant decrease of pain intensity level as well as improved shoulder functioning and sustained level of subject self-efficacy beliefs throughout the study period. The results suggest that it is possible to relieve shoulder pain intensity and improve daily activities of patients with diabetes-related shoulder problems by employing a physiotherapy program focusing on muscle relaxation, light-load exercise and on the enhancement of proper shoulder co-ordination in daily activities. A physiotherapy program can be effective in reducing pain and improving shoulder function in diabetics with shoulder problems. The treatment should focus on muscle relaxation, light-load exercise and on the enhancement of proper shoulder co-ordination in daily activities.

Simultaneous Transplantation of Hematopoietic Stem Cells and a Vascularized Composite Allograft Leads to Tolerance

PubMed Central

Mathes, David W.; Chang, Jeff; Hwang, Billanna; Graves, Scott S.; Storer, Barry E.; Butts-Miwongtum, Tiffany; Sale, George E.; Storb, Rainer

2014-01-01

Background We have previously demonstrated that tolerance to a vascularized composite allograft (VCA) can be achieved after the establishment of mixed chimerism. Here, we test the hypothesis that tolerance to a VCA in our dog leukocyte antigen (DLA)-matched canine model is not dependent on the previous establishment of mixed chimerism and can be induced coincident with hematopoietic cell transplantation (HCT). Methods Eight DLA-matched, minor antigen mismatched dogs received 200 cGy of radiation and a VCA transplant. Four dogs received donor bone marrow at the time of VCA transplantation (group 1) while a second group of 4 dogs did not (group 2). All recipients received a limited course of post-grafting immunosuppression. All dogs that received HCT and VCA were given donor, third party and autologous skin grafts. Results All group 1 recipients were tolerant to their VCA (> 62 weeks). Three of the four dogs in group 2 rejected their VCA transplants after the cessation of immunosuppression. Biopsies obtained from muscle and skin of VCA from group 1 showed few infiltrating cells compared to extensive infiltrates in biopsies of VCA from group 2. Compared to autologous skin and muscle, elevated levels of CD3+ FoxP3+ T-regulatory cells were found in skin and muscle obtained from VCA of HCT recipients. All group 1 animals were tolerant to their donor skin graft and promptly rejected the third-part skin grafts. Conclusion These data demonstrated donor specific tolerance to all components of the VCA can be established through simultaneous nonmyeloablative allogeneic HCT and VCA transplant protocol. PMID:24918616

RELIABILITY AND VALIDITY OF A MODIFIED ISOMETRIC DYNAMOMETER IN THE ASSESSMENT OF MUSCULAR PERFORMANCE IN INDIVIDUALS WITH ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

PubMed Central

de Vasconcelos, Rodrigo Antunes; Bevilaqua-Grossi, Débora; Shimano, Antonio Carlos; Paccola, Cleber Jansen; Salvini, Tânia Fátima; Prado, Christiane Lanatovits; Junior, Wilson A. Mello

2015-01-01

Objectives: The aim of this study was to evaluate the reliability and validity of a modified isometric dynamometer (MID) in performance deficits of the knee extensor and flexor muscles in normal individuals and in those with ACL reconstructions. Methods: Sixty male subjects were invited to participate of the study, being divided into three groups with 20 subjects each: control group (GC), group of individuals with ACL reconstruction with patellar tendon graft (GTP, and group of individuals with ACL reconstruction with hamstrings graft (GTF). All individuals performed isometric tests in the MID, muscular strength deficits collected were subsequently compared to the tests performed on the Biodex System 3 operating in the isometric and isokinetic mode at speeds of 60°/s and 180o/s. Intraclass ICC correlation calculations were done in order to assess MID reliability, specificity, sensitivity and Kappa's consistency coefficient calculations, respectively, for assessing the MID's validity in detecting muscular deficits and intra- and intergroup comparisons when performing the four strength tests using the ANOVA method. Results: The modified isometric dynamometer (MID) showed excellent reliability and good validity in the assessment of the performance of the knee extensor and flexor muscles groups. In the comparison between groups, the GTP showed significantly greater deficits as compared to the GTF and GC groups. Conclusion: Isometric dynamometers connected to mechanotherapy equipments could be an alternative option to collect data concerning performance deficits of the extensor and flexor muscles groups of the knee in subjects with ACL reconstruction. PMID:27004175

Invited Article: Recommendations of the Neurolaryngology Study Group on Laryngeal Electromyography

PubMed Central

Blitzer, Andrew; Crumley, Roger L.; Dailey, Seth H.; Ford, Charles N.; Floeter, Mary Kay; Hillel, Allen D.; Hoffman, Henry T.; Ludlow, Christy L.; Merati, Albert; Munin, Michael C.; Robinson, Lawrence R.; Rosen, Clark; Saxon, Keith G.; Sulica, Lucian; Thibeault, Susan L.; Titze, Ingo; Woo, Peak; Woodson, Gayle E.

2009-01-01

The Neurolaryngology Study Group convened a multidisciplinary panel of experts in neuromuscular physiology, electromyography, physical medicine and rehabilitation, neurology, and laryngology to meet with interested members from the American Academy of Otolaryngology Head and Neck Surgery, the Neurolaryngology Subcommittee and the Neurolaryngology Study Group to address the use of laryngeal electromyography (LEMG) for electrodiagnosis of laryngeal disorders. The panel addressed the use of LEMG for: 1) diagnosis of vocal fold paresis, 2) best practice application of equipment and techniques for LEMG, 3) estimation of time of injury and prediction of recovery of neural injuries, 4) diagnosis of neuromuscular diseases of the laryngeal muscles, and, 5) differentiation between central nervous system and behaviorally based laryngeal disorders. The panel also addressed establishing standardized techniques and methods for future assessment of LEMG sensitivity, specificity and reliability for identification, assessment and prognosis of neurolaryngeal disorders. Previously an evidence-based review of the clinical utility of LEMG published in 2004 only found evidence supported that LEMG was possibly useful for guiding injections of botulinum toxin into the laryngeal muscles. An updated traditional/narrative literature review and expert opinions were used to direct discussion and format conclusions. In current clinical practice, LEMG is a qualitative and not a quantitative examination. Specific recommendations were made to standardize electrode types, muscles to be sampled, sampling techniques, and reporting requirements. Prospective studies are needed to determine the clinical utility of LEMG. Use of the standardized methods and reporting will support future studies correlating electro-diagnostic findings with voice and upper airway function. PMID:19467391

THE EFFECT OF A PELVIC COMPRESSION BELT ON FUNCTIONAL HAMSTRING MUSCLE ACTIVITY IN SPORTSMEN WITH AND WITHOUT PREVIOUS HAMSTRING INJURY.

PubMed

Arumugam, Ashokan; Milosavljevic, Stephan; Woodley, Stephanie; Sole, Gisela

2015-06-01

There is evidence that applying a pelvic compression belt (PCB) can decrease hamstring and lumbar muscle electromyographic activity and increase gluteus maximus activity in healthy women during walking. Increased isokinetic eccentric hamstring strength in the terminal range (25 ° - 5 °) of knee extension has been reported with the use of such a belt in sportsmen with and without hamstring injuries. However, it is unknown whether wearing a pelvic belt alters activity of the hamstrings in sportsmen during walking. To examine the effects of wearing a PCB on electromyographic activity of the hamstring and lumbopelvic muscles during walking in sportsmen with and without hamstring injuries. Randomised crossover, cross-sectional study. Thirty uninjured sportsmen (23.53 ± 3.68 years) and 20 sportsmen with hamstring injuries (22.00 ± 1.45 years) sustained within the previous 12 months participated in this study. Electromyographic amplitudes of the hamstrings, gluteus maximus, gluteus medius and lumbar multifidus were monitored during defined phases of walking and normalised to maximum voluntary isometric contraction. Within-group comparisons [PCB vs. no PCB] for the normalised electromyographic amplitudes were performed for each muscle group using paired t tests. Electromyographic change scores [belt - no belt] were calculated and compared between the two groups with independent t tests. No significant change was evident in hamstring activity for either group while walking with the PCB (p > 0.050). However, with the PCB, gluteus medius activity (p ≤ 0.028) increased in both groups, while gluteus maximus activity increased (p = 0.025) and multifidus activity decreased (p < 0.001) in the control group. The magnitude of change induced by the PCB in gluteus medius activity was similar between groups (p = 0.760). No statistically significant baseline differences in no belt scores were evident between groups for the investigated muscles (p ≥ 0.050). Application of a PCB had individual-specific effects on electromyographic activity of injured and uninjured hamstrings during walking, resulting in no significant changes within or between the two groups. Future studies investigating effects of the PCB on hamstring activity in participants with acute injury and during a more demanding functional activity such as running are warranted. Level 3.

Diagnostic Utility of Auto-Antibodies in Inflammatory Muscle Diseases.

PubMed

Allenbach, Y; Benveniste, O

2015-01-01

To date, there are four main groups of idiopathic inflammatory myopathies (IIM): polymyositis (PM), dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM) and sporadic inclusion body myositis; based on clinical presentation and muscle pathology. Nevertheless, important phenotypical differences (either muscular and/or extra-muscular manifestations) within a group persist. In recent years, the titration of different myositis-specific (or associated) auto-antibodies as a diagnostic tool has increased. This is an important step forward since it may facilitate, at a viable cost, the differential diagnosis between IIM and other myopathies. We have now routine access to assays for the detection of different antibodies. For example, IMNM are related to the presence of anti-SRP or anti-HMGCR. PM is associated with anti-synthetase antibodies (anti-Jo-1, PL-7, PL-12, OJ, and EJ) and DM with anti-Mi-2, anti-SAE, anti-TIF-1-γ and anti-NXP2 (both associated with cancer) or anti-MDA5 antibodies (associated with interstitial lung disease). Today, over 30 myositis specific and associated antibodies have been characterised, and all groups of myositis may present one of those auto-antibodies. Most of them allow identification of homogenous patient groups, more precisely than the classical international classifications of myositis. This implies that classification criteria could be modified accordingly, since these auto-antibodies delineate groups of patients suffering from myositis with consistent clinical phenotype (muscular and extra-muscular manifestations), common prognostic (cancer association, presence of interstitial lung disease, mortality and risk of relapse) and treatment responses. Nevertheless, since numerous auto-antibodies have been recently characterised, the exact prevalence of myositis specific antibodies remains to be documented, and research of new auto-antibodies in the remaining seronegative group is still needed.

Impaired hip muscle strength in patients with femoroacetabular impingement syndrome.

PubMed

Kierkegaard, Signe; Mechlenburg, Inger; Lund, Bent; Søballe, Kjeld; Dalgas, Ulrik

2017-12-01

Patients with femoroacetabular impingement (FAI) experience hip pain as well as decreased function and lowered quality of life. The aim was to compare maximal isometric and isokinetic muscle strength (MVC) during hip flexion and extension and rate of force development (RFD) during extension between patients with FAI and a matched reference group. Secondary, the aim was to compare patient hips and subgroups defined by gender and age as well as to investigate associations between hip muscle strength and self-reported outcomes. Design Cross-sectional, comparative study Methods Sixty patients (36±9 years, 63% females) and 30 age and gender matched reference persons underwent MVC tests in an isokinetic dynamometer. During hip flexion and extension, patients' affected hip showed a strength deficit of 15-21% (p<0.001) and 10-25% (p<0.03) compared with reference MVC, respectively. The affected hip of the patients was significantly weaker than their contralateral hip. RFD was significantly decreased for both patient hips compared to the reference group (p<0.05). While age had less effect on MVC, female patients were more affected than male patients. Self-reported measures were associated with isometric hip muscle strength. Patients with FAI demonstrate decreased hip flexion and extension strength when compared to (1) reference persons and (2) their contralateral hip. There seems to be a gender specific affection which should be investigated further and addressed when planning training protocols. Furthermore, self-reported measures were associated with isometric muscle strength, which underlines the clinical importance of the reduced muscle strength. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Shoulder muscle strength in paraplegics before and after kayak ergometer training.

PubMed

Bjerkefors, Anna; Jansson, Anna; Thorstensson, Alf

2006-07-01

The purpose was to investigate if shoulder muscle strength in post-rehabilitated persons with spinal cord injury (SCI) was affected by kayak ergometer training and to compare shoulder strength in persons with SCI and able-bodied persons. Ten persons with SCI (7 males and 3 females, injury levels T3-T12) performed 60 min kayak ergometer training three times a week for 10 weeks with progressively increased intensity. Maximal voluntary concentric contractions were performed during six shoulder movements: flexion and extension (range of motion 65 degrees ), abduction and adduction (65 degrees ), and external and internal rotation (60 degrees ), with an angular velocity of 30 degrees s(-1). Position specific strength was assessed at three shoulder angles (at the beginning, middle and end of the range of motion) in the respective movements. Test-retests were performed for all measurements before the training and the mean intraclass correlation coefficient was 0.941 (95% CI 0.928-0.954). There was a main effect of kayak ergometer training with increased shoulder muscle strength after training in persons with SCI. The improvements were independent of shoulder movement, and occurred in the beginning and middle positions. A tendency towards lower shoulder muscle strength was observed in the SCI group compared to a matched reference group of able-bodied persons. Thus, it appears that post-rehabilitated persons with SCI have not managed to fully regain/maintain their shoulder muscle strength on a similar level as that of able-bodied persons, and are able to improve their shoulder muscle strength after a period of kayak ergometer training.

Isometric muscle strength and mobility capacity in children with cerebral palsy.

PubMed

Dallmeijer, Annet J; Rameckers, Eugene A; Houdijk, Han; de Groot, Sonja; Scholtes, Vanessa A; Becher, Jules G

2017-01-01

To determine the relationship between isometric leg muscle strength and mobility capacity in children with cerebral palsy (CP) compared to typically developing (TD) peers. Participants were 62 children with CP (6-13 years), able to walk with (n = 10) or without (n = 52) walking aids, and 47 TD children. Isometric muscle strength of five muscle groups of the leg was measured using hand-held dynamometry. Mobility capacity was assessed with the 1-min walk, the 10-m walk, sit-to-stand, lateral-step-up and timed-stair tests. Isometric strength of children with CP was reduced to 36-82% of TD. When adjusted for age and height, the percentage of variance in mobility capacity that was explained by isometric strength of the leg muscles was 21-24% (walking speed), 25% (sit-to-stand), 28% (lateral-step-up) and 35% (timed-stair) in children with CP. Hip abductors and knee flexors had the largest contribution to the explained variance, while knee extensors showed the weakest correlation. Weak or no associations were found between strength and mobility capacity in TD children. Isometric strength, especially hip abductor and knee flexor strength, is moderately related to mobility capacity in children with CP, but not in TD children. To what extent training of these muscle groups will lead to better mobility capacity needs further study. Implications for Rehabilitation Strength training in children with cerebral palsy (CP) may be targeted more specifically at hip abductors and knee flexors. The moderate associations imply that large improvements in mobility capacity may not be expected when strength increases.

Evidence that a maternal "junk food" diet during pregnancy and lactation can reduce muscle force in offspring.

PubMed

Bayol, Stéphanie A; Macharia, Raymond; Farrington, Samantha J; Simbi, Bigboy H; Stickland, Neil C

2009-02-01

Obesity is a multi-factorial condition generally attributed to an unbalanced diet and lack of exercise. Recent evidence suggests that maternal malnutrition during pregnancy and lactation can also contribute to the development of obesity in offspring. We have developed an animal model in rats to examine the effects of maternal overeating on a westernized "junk food" diet using palatable processed foods rich in fat, sugar and salt designed for human consumption. Using this model, we have shown that such a maternal diet can promote overeating and a greater preference for junk food in offspring at the end of adolescence. The maternal junk food diet also promoted adiposity and muscle atrophy at weaning. Impaired muscle development may permanently affect the function of this tissue including its ability to generate force. The aim of this study is to determine whether a maternal junk food diet can impair muscle force generation in offspring. Twitch and tetanic tensions were measured in offspring fed either chow alone (C) or with a junk food diet (J) during gestation, lactation and/or post-weaning up to the end of adolescence such that three groups of offspring were used, namely the CCC, JJC and JJJ groups. We show that adult offspring from mothers fed the junk food diet in pregnancy and lactation display reduced muscle force (both specific twitch and tetanic tensions) regardless of the post-weaning diet compared with offspring from mothers fed a balanced diet. Maternal malnutrition can influence muscle force production in offspring which may affect an individual's ability to exercise and thereby combat obesity.

Association of low back pain with muscle stiffness and muscle mass of the lumbar back muscles, and sagittal spinal alignment in young and middle-aged medical workers.

PubMed

Masaki, Mitsuhiro; Aoyama, Tomoki; Murakami, Takashi; Yanase, Ko; Ji, Xiang; Tateuchi, Hiroshige; Ichihashi, Noriaki

2017-11-01

Muscle stiffness of the lumbar back muscles in low back pain (LBP) patients has not been clearly elucidated because quantitative assessment of the stiffness of individual muscles was conventionally difficult. This study aimed to examine the association of LBP with muscle stiffness assessed using ultrasonic shear wave elastography (SWE) and muscle mass of the lumbar back muscle, and spinal alignment in young and middle-aged medical workers. The study comprised 23 asymptomatic medical workers [control (CTR) group] and 9 medical workers with LBP (LBP group). Muscle stiffness and mass of the lumbar back muscles (lumbar erector spinae, multifidus, and quadratus lumborum) in the prone position were measured using ultrasonic SWE. Sagittal spinal alignment in the standing and prone positions was measured using a Spinal Mouse. The association with LBP was investigated by multiple logistic regression analysis with a forward selection method. The analysis was conducted using the shear elastic modulus and muscle thickness of the lumbar back muscles, and spinal alignment, age, body height, body weight, and sex as independent variables. Multiple logistic regression analysis showed that muscle stiffness of the lumbar multifidus muscle and body height were significant and independent determinants of LBP, but that muscle mass and spinal alignment were not. Muscle stiffness of the lumbar multifidus muscle in the LBP group was significantly higher than that in the CTR group. The results of this study suggest that LBP is associated with muscle stiffness of the lumbar multifidus muscle in young and middle-aged medical workers. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Relationship Between Postural and Movement Stability.

PubMed

Feldman, Anatol G

2016-01-01

Postural stabilization is provided by stretch reflexes, intermuscular reflexes, and intrinsic muscle properties. Taken together, these posture-stabilizing mechanisms resist deflections from the posture at which balance of muscle and external forces is maintained. Empirical findings suggest that for each muscle, these mechanisms become functional at a specific, spatial threshold-the muscle length or respective joint angle at which motor units begin to be recruited. Empirical data suggest that spinal and supraspinal centers can shift the spatial thresholds for a group of muscles that stabilized the initial posture. As a consequence, the same stabilizing mechanisms, instead of resisting motion from the initial posture, drive the body to another stable posture. In other words by shifting spatial thresholds, the nervous system converts movement resisting to movement-producing mechanisms. It is illustrated that, contrary to conventional view, this control strategy allows the system to transfer body balance to produce locomotion and other actions without loosing stability at any point of them. It also helps orient posture and movement with the direction of gravity. It is concluded that postural and movement stability is provided by a common mechanism.

Cancer cachexia decreases specific force and accelerates fatigue in limb muscle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, B.M.; Frye, G.S.; Ahn, B.

Highlights: •C-26 cancer cachexia causes a significant decrease in limb muscle absolute force. •C-26 cancer cachexia causes a significant decrease in limb muscle specific force. •C-26 cancer cachexia decreases fatigue resistance in the soleus muscle. •C-26 cancer cachexia prolongs time to peak twitch tension in limb muscle. •C-26 cancer cachexia prolongs one half twitch relaxation time in limb muscle. -- Abstract: Cancer cachexia is a complex metabolic syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia havemore » recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. However, more recently, we provided evidence that during severe cancer cachexia muscle weakness in the diaphragm muscle cannot be entirely accounted for by the muscle atrophy. This indicates that muscle weakness is not just a consequence of muscle atrophy but that there is also significant contractile dysfunction. The current study aimed to determine whether contractile dysfunction is also present in limb muscles during severe Colon-26 (C26) carcinoma cachexia by studying the glycolytic extensor digitorum longus (EDL) muscle and the oxidative soleus muscle, which has an activity pattern that more closely resembles the diaphragm. Severe C-26 cancer cachexia caused significant muscle fiber atrophy and a reduction in maximum absolute force in both the EDL and soleus muscles. However, normalization to muscle cross sectional area further demonstrated a 13% decrease in maximum isometric specific force in the EDL and an even greater decrease (17%) in maximum isometric specific force in the soleus. Time to peak tension and half relaxation time were also significantly slowed in both the EDL and the solei from C-26 mice compared to controls. Since, in addition to postural control, the oxidative soleus is also important for normal locomotion, we further performed a fatigue trial in the soleus and found that the decrease in relative force was greater and more rapid in solei from C-26 mice compared to controls. These data demonstrate that severe cancer cachexia causes profound muscle weakness that is not entirely explained by the muscle atrophy. In addition, cancer cachexia decreases the fatigue resistance of the soleus muscle, a postural muscle typically resistant to fatigue. Thus, specifically targeting contractile dysfunction represents an additional means to counter muscle weakness in cancer cachexia, in addition to targeting the prevention of muscle atrophy.« less

Loss of Calpain 3 Proteolytic Activity Leads to Muscular Dystrophy and to Apoptosis-Associated Iκbα/Nuclear Factor κb Pathway Perturbation in Mice

PubMed Central

Richard, Isabelle; Roudaut, Carinne; Marchand, Sylvie; Baghdiguian, Stephen; Herasse, Muriel; Stockholm, Daniel; Ono, Yasuko; Suel, Laurence; Bourg, Nathalie; Sorimachi, Hiroyuki; Lefranc, Gérard; Fardeau, Michel; Sébille, Alain; Beckmann, Jacques S.

2000-01-01

Calpain 3 is known as the skeletal muscle–specific member of the calpains, a family of intracellular nonlysosomal cysteine proteases. It was previously shown that defects in the human calpain 3 gene are responsible for limb girdle muscular dystrophy type 2A (LGMD2A), an inherited disease affecting predominantly the proximal limb muscles. To better understand the function of calpain 3 and the pathophysiological mechanisms of LGMD2A and also to develop an adequate model for therapy research, we generated capn3-deficient mice by gene targeting. capn3-deficient mice are fully fertile and viable. Allele transmission in intercross progeny demonstrated a statistically significant departure from Mendel's law. capn3-deficient mice show a mild progressive muscular dystrophy that affects a specific group of muscles. The age of appearance of myopathic features varies with the genetic background, suggesting the involvement of modifier genes. Affected muscles manifest a similar apoptosis-associated perturbation of the IκBα/nuclear factor κB pathway as seen in LGMD2A patients. In addition, Evans blue staining of muscle fibers reveals that the pathological process due to calpain 3 deficiency is associated with membrane alterations. PMID:11134085

Functional rescue of dystrophin-deficient mdx mice by a chimeric peptide-PMO.

PubMed

Yin, Haifang; Moulton, Hong M; Betts, Corinne; Merritt, Thomas; Seow, Yiqi; Ashraf, Shirin; Wang, Qingsong; Boutilier, Jordan; Wood, Matthew Ja

2010-10-01

Splice modulation using antisense oligonucleotides (AOs) has been shown to yield targeted exon exclusion to restore the open reading frame and generate truncated but partially functional dystrophin protein. This has been successfully demonstrated in dystrophin-deficient mdx mice and in Duchenne muscular dystrophy (DMD) patients. However, DMD is a systemic disease; successful therapeutic exploitation of this approach will therefore depend on effective systemic delivery of AOs to all affected tissues. We have previously shown the potential of a muscle-specific/arginine-rich chimeric peptide-phosphorodiamidate morpholino (PMO) conjugate, but its long-term activity, optimized dosing regimen, capacity for functional correction and safety profile remain to be established. Here, we report the results of this chimeric peptide-PMO conjugate in the mdx mouse using low doses (3 and 6 mg/kg) administered via a 6 biweekly systemic intravenous injection protocol. We show 100% dystrophin-positive fibers and near complete correction of the dystrophin transcript defect in all peripheral muscle groups, with restoration of 50% dystrophin protein over 12 weeks, leading to correction of the DMD pathological phenotype and restoration of muscle function in the absence of detectable toxicity or immune response. Chimeric muscle-specific/cell-penetrating peptides therefore represent highly promising agents for systemic delivery of splice-correcting PMO oligomers for DMD therapy.

The Influence of Protein Supplementation on Muscle Hypertrophy

NASA Astrophysics Data System (ADS)

Fardi, A.; Welis, W.

2018-04-01

The problem of this study was the lack of knowledge about nutrition, so the use of protein supplements to support the occurrence of muscle hypertrophy is not optimal. The use of natural supplements is a substitute of the manufacturer's supplements. The purpose of this study was to determine the effect of natural protein supplementation to muscle hypertrophy.The method of the research was a quasi experiment. There are 26 subject and were divided two group. Instrument of this research is to use tape measure and skinfold to measure muscle rim and thickness of fat in arm and thigh muscle. Then to calculate the circumference of the arm and thigh muscles used the formula MTC - (3.14 x TSF). MTC is the arm muscle or thigh muscle and TSF is the thickness of the muscles of the arm or thigh muscles. Data analysis technique used was t test at 5% significant level. The result of the research showed that average score of arm muscle hypertrophy at pretest control group was 255.61 + 17.69 mm and posttest average score was 263.48.58 + 17.21 mm and average score of thigh muscle hypertrophy at pretest control group was 458.32 + 8.72 mm and posttest average score was 468.78 + 11.54 mm. Average score of arm muscle hypertrophy at pretest experiment group was 252.67 + 16.05 mm and posttest average score was 274.58 ± 16.89 mm and average score of thigh muscle hypertrophy at pretest experiment group was 459.49 ± 6.99 mm and posttest average score was 478.70 + 9.05 mm. It can be concluded that there was a significant effect of natural protein supplementation on muscle hypertrophy.

Prolonging the duration of masseter muscle reduction by adjusting the masticatory movements after the treatment of masseter muscle hypertrophy with botulinum toxin type a injection.

PubMed

Wei, Jiao; Xu, Hua; Dong, Jiasheng; Li, Qingfeng; Dai, Chuanchang

2015-01-01

Botulinum toxin type A (BTX-A) is widely used for the clinical treatment of masseteric hypertrophy. Until now, few reports have discussed how to prolong the duration of its effectiveness. This study evaluated that purposely adjusting the masticatory movements is possible of postponing the masseter muscle rehypertrophy. Ninety-eight patients were randomly and equally divided into 2 groups, and 35 U BTX-A per side was injected into the masseters. The thickness and volume of the masticatory muscles were measured by ultrasound and computerized tomography, respectively. Patients in Group 1 were instructed to strengthen their masticatory effort during the denervated atrophic stage of the masseter (the interval was evaluated by real-time ultrasound monitoring), whereas patients in Group 2 were not given this instruction. When the masseter muscle began to recover, patients in both groups were instructed to reduce their chewing. The duration of the masseter muscle rehypertrophy was significantly prolonged in Group 1 patients. The thickness and the volume of the other masticatory muscles were significantly increased in Group 1 but were either slightly decreased or insignificantly different in Group 2. Purposely strengthening masticatory muscle movement during the denervated atrophic stage of the masseter can prolong the duration of masseter rehypertrophy.

Muscle damage and repeated bout effect following blood flow restricted exercise.

PubMed

Sieljacks, Peter; Matzon, Andreas; Wernbom, Mathias; Ringgaard, Steffen; Vissing, Kristian; Overgaard, Kristian

2016-03-01

Blood-flow restricted resistance exercise training (BFRE) is suggested to be effective in rehabilitation training, but more knowledge is required about its potential muscle damaging effects. Therefore, we investigated muscle-damaging effects of BFRE performed to failure and possible protective effects of previous bouts of BFRE or maximal eccentric exercise (ECC). Seventeen healthy young men were allocated into two groups completing two exercise bouts separated by 14 days. One group performed BFRE in both exercise bouts (BB). The other group performed ECC in the first and BFRE in the second bout. BFRE was performed to failure. Indicators of muscle damage were evaluated before and after exercise. The first bout in the BB group led to decrements in maximum isometric torque, and increases in muscle soreness, muscle water retention, and serum muscle protein concentrations after exercise. These changes were comparable in magnitude and time course to what was observed after first bout ECC. An attenuated response was observed in the repeated exercise bout in both groups. We conclude that unaccustomed single-bout BFRE performed to failure induces significant muscle damage. Additionally, both ECC and BFRE can precondition against muscle damage induced by a subsequent bout of BFRE.

Ascorbic Acid Attenuates Multifidus Muscles Injury and Atrophy after Posterior Lumbar Spine Surgery by Suppressing Inflammation and Oxidative Stress in a Rat Model.

PubMed

Tang, Pan; Gu, Yu; Gu, Jia-Ming; Xie, Zi-Ang; Xu, Jia-Qi; Zhao, Xiang-De; Huang, Kang-Mao; Wang, Ji-Ying; Jiang, Xue-Sheng; Fan, Shun-Wu; Hu, Zhi-Jun

2018-04-11

A rat model of multifidus muscles injury and atrophy after posterior lumbar spine surgery. We determined the effect of ascorbic acid (AA) on the postoperative multifidus muscles in rat model. Previous studies show oxidative stress and inflammation are two main molecular mechanisms in multifidus muscle injury and atrophy after posterior lumbar surgery. AA may have a protective effect in postoperative multifidus muscles. Rats were divided into sham surgery, control surgery, and surgery plus AA groups. Multifidus muscles of the control and AA groups were excised from the osseous structures. The muscles were retracted continuously for 2 h. In the sham and AA groups, AA was administered via oral gavage daily in the first week. In each group, the oxidative stress was evaluated by measuring malondialdehyde (MDA) and Total superoxide dismutase (T-SOD). The inflammation, fat degeneration or fibrosis of multifidus muscle were evaluated by Q-PCR, histology or immunohistochemical analysis. T-SOD activity was significantly lower in the control group than that in the AA group in the first week. MDA levels were significantly higher in the AA group. Interleukin-6 and tumor necrosis factor-α in multifidus muscles also showed significant differences when treated with AA. The inflammation score on histology was significantly lower in the AA group postoperatively in the first week. In the long run, marker genes for fibrosis and fat degeneration, and fibrosis and fat degeneration scores, were significantly lower in the AA than the control group on days 14 and 28 postoperatively. In conclusion, AA attenuated the oxidative stress and inflammation response in the postoperative multifidus muscles, and remarkable differences were observed from the histological assessment and related marker genes expression. Our results provided important insight into the anti-inflammatory and anti-oxidative effects of AA in the postoperative multifidus muscles. N/A.

Overexpression of insulin-like growth factor-1 attenuates skeletal muscle damage and accelerates muscle regeneration and functional recovery after disuse.

PubMed

Ye, Fan; Mathur, Sunita; Liu, Min; Borst, Stephen E; Walter, Glenn A; Sweeney, H Lee; Vandenborne, Krista

2013-05-01

Skeletal muscle is a highly dynamic tissue that responds to endogenous and external stimuli, including alterations in mechanical loading and growth factors. In particular, the antigravity soleus muscle experiences significant muscle atrophy during disuse and extensive muscle damage upon reloading. Given that insulin-like growth factor-1 (IGF-1) has been implicated as a central regulator of muscle repair and modulation of muscle size, we examined the effect of virally mediated overexpression of IGF-1 on the soleus muscle following hindlimb cast immobilization and upon reloading. Recombinant IGF-1 cDNA virus was injected into one of the posterior hindlimbs of the mice, while the contralateral limb was injected with saline (control). At 20 weeks of age, both hindlimbs were immobilized for 2 weeks to induce muscle atrophy in the soleus and ankle plantarflexor muscle group. Subsequently, the mice were allowed to reambulate, and muscle damage and recovery were monitored over a period of 2-21 days. The primary finding of this study was that IGF-1 overexpression attenuated reloading-induced muscle damage in the soleus muscle, and accelerated muscle regeneration and force recovery. Muscle T2 assessed by magnetic resonance imaging, a non-specific marker of muscle damage, was significantly lower in IGF-1-injected compared with contralateral soleus muscles at 2 and 5 days reambulation (P<0.05). The reduced prevalence of muscle damage in IGF-1-injected soleus muscles was confirmed on histology, with a lower fractional area of abnormal muscle tissue in IGF-1-injected muscles at 2 days reambulation (33.2±3.3 versus 54.1±3.6%, P<0.05). Evidence of the effect of IGF-1 on muscle regeneration included timely increases in the number of central nuclei (21% at 5 days reambulation), paired-box transcription factor 7 (36% at 5 days), embryonic myosin (37% at 10 days) and elevated MyoD mRNA (7-fold at 2 days) in IGF-1-injected limbs (P<0.05). These findings demonstrate a potential role of IGF-1 in protecting unloaded skeletal muscles from damage and accelerating muscle repair and regeneration.

Anatomical differences in the psoas muscles in young black and white men

PubMed Central

HANSON, PATRICK; MAGNUSSON, S. PETER; SORENSEN, HENRIK; SIMONSEN, ERIK B.

1999-01-01

The anatomy of the psoas major muscle (PMA) in young black and white men was studied during routine autopsies. The forensic autopsies included 44 fresh male cadavers (21 black, 23 white) with an age span of 14 to 25 y. The range for weight was 66–76 kg and for height 169–182 cm. The PMA was initially measured in its entire length before measuring the diameter and circumference at each segmental level (L1–S1). At each segmental level, the calculated anatomical cross-sectional area (ACSA) was more than 3 times greater in the black group compared with the white (P<0.001). The psoas minor muscle (PMI) was absent in 91% of the black subjects, but only in 13% of the white subjects. These data show that the PMA is markedly larger in black than white subjects. The marked race specific difference in the size of the PMA may have implications for hip flexor strength, spine function and race specific incidence in low back pathology, and warrants further investigation. PMID:10337963

Botulinum neurotoxin effects on masseter muscle fibre in WNIN obese rats-Scanning electron microscope analysis.

PubMed

Nemani, Shivaram; Putchha, Uday K; Periketi, Madhusudhanachary; Pothana, Sailaja; Nappanveettil, Giridharan; Nemani, Harishankar

2016-09-01

WNIN/Ob obese mutant rats are unique in comparison to similar rodent models of obesity established in the West. The present study is aimed to evaluate the masticatory function and histological changes in masseter muscle fibres treated with botulinum toxin type A (BoNT/A) in WNIN/Ob rats. Twelve WNIN/Ob obese rats and 12 lean rats at 35 days of age were taken and divided into four groups (6 rats in each group): Group-I (WNIN/Ob) and Group-II (lean) rats were injected with BoNT/A (1 unit) into right side of masseter muscle. For control left masseter of both phenotypes was injected with saline. Group-III (WNIN/Ob) and Group-IV (lean) rats were without any treatment. Growth and food intake was monitored daily for 45 days. Rats were euthanized and gross necropsy was carried out to check any abnormalities. Masseter muscles were dissected and mean muscle mass was recorded. Small portion of muscle was stored in 10% formalin for hematoxylin-eosin (H&E) staining and remaining tissue stored in gluteraldehyde for scanning electron microscopy (SEM). There is a significant decrease in the body weights and food intake of BoNT/A treated obese rats. The H&E staining of the masseter muscle in both groups showed normal morphology and orientation. The SEM analysis showed that, fibre size in BoNT/A treated masseter muscle of obese rats increased more than the saline treated side and in control rats. The increase in the muscle fibre size and transition of muscle fibre subtypes may be due to the reduced masticatory function of the masseter muscle. SCANNING 38:396-402, 2016. © 2015 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Effects of Combined Spinal-Epidural Analgesia during Labor on Postpartum Electrophysiological Function of Maternal Pelvic Floor Muscle: A Randomized Controlled Trial.

PubMed

Xing, Ji-Juan; Liu, Xiu-Fen; Xiong, Xiao-Ming; Huang, Li; Lao, Cheng-Yi; Yang, Mei; Gao, Shan; Huang, Qiong-Yan; Yang, Wei; Zhu, Yun-Feng; Zhang, Di-Hua

2015-01-01

Combined spinal-epidural analgesia (CSEA) is sometimes used for difficult births, but whether it contributes to postpartum pelvic muscle disorder is unclear. This randomized controlled trial examined whether CSEA given during labor affects the electrophysiological index of postpartum pelvic floor muscle function. A consecutive sample of primiparous women who delivered vaginally at term were randomly assigned to a CSEA group (n = 143) and control group (n = 142) between June 2013 and June 2014. All were assessed 6-8 weeks later for electrophysiological function of pelvic floor muscle. The two groups were similar in the degree of muscle strength, muscle fatigue, and pelvic dynamic pressure of pelvic floor muscle. The CSEA and control groups showed similar proportions of women with normal muscle strength (score ≥4) in type I pelvic fibers (23.1% vs. 14.1%, P = 0.051) and type II pelvic fibers (28.0% vs. 24.6%, P = 0.524). The groups also contained similar proportions of women who showed no fatigue in type I fibers (54.5% vs. 48.6%, P = 0.315) or type II fibers (88.8% vs. 87.3%, P = 0.699). Similarly low proportions of women in the CSEA group and control group showed normal pelvic dynamic pressure (11.2% vs. 7.7%, P = 0.321). However, women in the CSEA group spent significantly less time in labor than those in the control group (7.25 vs. 9.52 h, P <0.001). CSEA did not affect the risk of postpartum pelvic muscle disorder in this cohort of primiparous women who gave birth vaginally. A significant shorter duration of labour was observed in the CSEA-group. ClinicalTrials.gov NCT02334150.

Effects of Combined Spinal-Epidural Analgesia during Labor on Postpartum Electrophysiological Function of Maternal Pelvic Floor Muscle: A Randomized Controlled Trial

PubMed Central

Xiong, Xiao-Ming; Huang, Li; Lao, Cheng-Yi; Yang, Mei; Gao, Shan; Huang, Qiong-Yan; Yang, Wei; Zhu, Yun-Feng; Zhang, Di-Hua

2015-01-01

Objective Combined spinal-epidural analgesia (CSEA) is sometimes used for difficult births, but whether it contributes to postpartum pelvic muscle disorder is unclear. This randomized controlled trial examined whether CSEA given during labor affects the electrophysiological index of postpartum pelvic floor muscle function. Methods A consecutive sample of primiparous women who delivered vaginally at term were randomly assigned to a CSEA group (n = 143) and control group (n = 142) between June 2013 and June 2014. All were assessed 6–8 weeks later for electrophysiological function of pelvic floor muscle. Results The two groups were similar in the degree of muscle strength, muscle fatigue, and pelvic dynamic pressure of pelvic floor muscle. The CSEA and control groups showed similar proportions of women with normal muscle strength (score ≥4) in type I pelvic fibers (23.1% vs. 14.1%, P = 0.051) and type II pelvic fibers (28.0% vs. 24.6%, P = 0.524). The groups also contained similar proportions of women who showed no fatigue in type I fibers (54.5% vs. 48.6%, P = 0.315) or type II fibers (88.8% vs. 87.3%, P = 0.699). Similarly low proportions of women in the CSEA group and control group showed normal pelvic dynamic pressure (11.2% vs. 7.7%, P = 0.321). However, women in the CSEA group spent significantly less time in labor than those in the control group (7.25 vs. 9.52 h, P <0.001). Conclusions CSEA did not affect the risk of postpartum pelvic muscle disorder in this cohort of primiparous women who gave birth vaginally. A significant shorter duration of labour was observed in the CSEA-group. Trial Registration ClinicalTrials.gov NCT02334150 PMID:26340002

The human desmin locus: gene organization and LCR-mediated transcriptional control.

PubMed

Tam, Jennifer L Y; Triantaphyllopoulos, Kostas; Todd, Helen; Raguz, Selina; de Wit, Ton; Morgan, Jennifer E; Partridge, Terence A; Makrinou, Eleni; Grosveld, Frank; Antoniou, Michael

2006-06-01

Locus control regions (LCRs) are defined by their ability to confer reproducible physiological levels of transgene expression in mice and therefore thought to possess the ability to generate dominantly a transcriptionally active chromatin structure. We report the first characterization of a muscle-cell-specific LCR, which is linked to the human desmin gene (DES). The DES LCR consists of five regions of muscle-specific DNase I hypersensitivity (HS) localized between -9 and -18 kb 5' of DES and reproducibly drives full physiological levels of expression in all muscle cell types. The DES LCR DNase I HS regions are highly conserved between humans and other mammals and can potentially bind a broad range of muscle-specific and ubiquitous transcription factors. Bioinformatics and direct molecular analysis show that the DES locus consists of three muscle-specific (DES) or muscle preferentially expressed genes (APEG1 and SPEG, the human orthologue of murine striated-muscle-specific serine/threonine protein kinase, Speg). The DES LCR may therefore regulate expression of SPEG and APEG1 as well as DES.

Age-related changes in trunk neuromuscular activation patterns during a controlled functional transfer task include amplitude and temporal synergies.

PubMed

Quirk, D Adam; Hubley-Kozey, Cheryl L

2014-12-01

While healthy aging is associated with physiological changes that can impair control of trunk motion, few studies examine how spinal muscle responses change with increasing age. This study examined whether older (over 65 years) compared to younger (20-45 years) adults had higher overall amplitude and altered temporal recruitment patterns of trunk musculature when performing a functional transfer task. Surface electromyograms from twelve bilateral trunk muscle (24) sites were analyzed using principal component analysis, extracting amplitude and temporal features (PCs) from electromyographic waveforms. Two PCs explained 96% of the waveform variance. Three factor ANOVA models tested main effects (group, muscle and reach) and interactions for PC scores. Significant (p<.0125) group interactions were found for all PC scores. Post hoc analysis revealed that relative to younger adults, older adults recruited higher agonist and antagonistic activity, demonstrated continuous activation levels in specific muscle sites despite changing external moments, and had altered temporal synergies within abdominal and back musculature. In summary both older and younger adults recruit highly organized activation patterns in response to changing external moments. Differences in temporal trunk musculature recruitment patterns suggest that older adults experience different dynamic spinal stiffness and loading compared to younger adults during a functional lifting task. Copyright © 2014 Elsevier B.V. All rights reserved.

Velocity associated characteristics of force production in college weight lifters.

PubMed

Kanehisa, H; Fukunaga, T

1999-04-01

To determine velocity specific isokinetic forces and cross sectional areas of reciprocal muscle groups in Olympic weight lifters. The cross sectional area of the flexor or extensor muscles of the elbow or knee joint was determined by a B-mode ultrasonic apparatus in 34 college weight lifters and 31 untrained male subjects matched for age. Maximum voluntary force produced in the flexion and extension of the elbow and knee joints was measured on an isokinetic dynamometer at 60, 180, and 300 degrees/s. The average cross sectional area was 31-65% higher, and the force was 19-62% higher in weight lifters than in the untrained subjects. The ratio of force to cross sectional area was the same in both groups. The weight lifters showed a lower velocity associated decline in force than untrained subjects in the elbow and knee flexors but not in the extensors. These results indicate that for muscle contractions with velocities between 60 degrees/s and 300 degrees/s the difference in isokinetic force between weight lifters and untrained subjects can be primarily attributed to the difference in the muscle cross sectional area. However, the lower velocity associated decline in force implies that weight lifters may have a higher force per cross sectional area than untrained subjects at velocities above 300 degrees/s.

Life-long calorie restriction in Fischer 344 rats attenuates age-related loss in skeletal muscle-specific force and reduces extracellular space.

PubMed

Payne, Anthony M; Dodd, Stephen L; Leeuwenburgh, Christiaan

2003-12-01

The decline in muscle function is associated with an age-related decrease in muscle mass and an age-related decline in strength. However, decreased strength is not solely due to decreased muscle mass. The age-related decline in muscle-specific force (force/muscle cross-sectional area), a measure of intrinsic muscle function, also contributes to age-related strength decline, and the mechanisms by which this occurs are only partially known. Moreover, changes in the extracellular space could have a profound effect on skeletal muscle function. Life-long calorie restriction in rodents has shown to be a powerful anti-aging intervention. In this study, we examine whether calorie restriction is able to attenuate the loss of muscle function and elevations in extracellular space associated with aging. We hypothesize that calorie restriction attenuates the age-associated decline in specific force and increases in extracellular space. Measurements of in vitro contractile properties of the extensor digitorum longus (type II) and soleus (type I) muscles from 12-mo and 26- to 28-mo-old ad libitum-fed, as well as 27- to 28-mo-old life-long calorie-restricted male Fischer 344 rats, were performed. We found that calorie restriction attenuated the age-associated decline in muscle mass-to-body mass ratio (mg/g) and strength-to-body mass ratio (N/kg) in the extensor digitorum longus muscle (P < 0.05) but not in the soleus muscle (P > 0.05). Importantly, muscle-specific force (N/cm2) in the extensor digitorum longus, but not in the soleus muscle, of the old calorie-restricted rats was equal to that of the young 12-mo-old animals. Moreover, the age-associated increase in extracellular space was reduced in the fast-twitch extensor digitorum longus muscle (P < 0.05) but not in the soleus muscle with calorie restriction. We also found a significant correlation between the extracellular space and the muscle-specific force in the extensor digitorum longus (r = -0.58; P < 0.05) but not in the soleus muscle (r = -0.38; P > 0.05). Hence, this study shows a loss of muscle function with age and suggests that long-term calorie restriction is an effective intervention against the loss of muscle function with age.

The Role of Rac1 on Carbachol-induced Contractile Activity in Detrusor Smooth Muscle from Streptozotocin-induced Diabetic Rats.

PubMed

Evcim, Atiye Sinem; Micili, Serap Cilaker; Karaman, Meral; Erbil, Guven; Guneli, Ensari; Gidener, Sedef; Gumustekin, Mukaddes

2015-06-01

This study was designed to determine the role of the small GTPase Rac1 on carbachol-induced contractile activity in detrusor smooth muscle using small inhibitor NSC 23766 in diabetic rats. Rac1 expression in bladder tissue was also evaluated. In the streptozotocin (STZ)-induced diabetic rat model, three study groups were composed of control, diabetic and insulin-treated diabetic subjects. The detrusor muscle strips were suspended in organ baths at the end of 8-12 weeks after STZ injection. Carbachol (CCh) (10(-9) -10(-4) M) concentration-response curves were obtained both in the absence and in the presence of Rac1 inhibitor NSC 23766 (0.1, 1 and 10 μM). Diabetes-related histopathological changes and Rac1 expressions were assessed by haematoxylin and eosin staining and immunohistochemical staining, respectively. CCh caused dose-dependent contractile responses in all the study groups. Rac1 inhibitor NSC 23766 inhibited CCh-induced contractile responses in all groups, but this inhibition seen in both diabetes groups was greater than in the control group. Histological examination revealed an increased bladder wall thickness both in the diabetes and in the insulin-treated diabetes groups compared to the control group. In immunohistochemical staining, expression of Rac1 was observed to be increased in all layers of bladder in both diabetic groups compared to the control group. In the diabetic bladders, increased expression of Rac1 and considerable inhibition of CCh-induced responses in the presence of NSC 23766 compared to those of the control group may indicate a specific role of Rac1 in diabetes-related bladder dysfunction, especially associated with cholinergic mediated detrusor overactivity. © 2014 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

The fate of neurotization techniques on reinnervation after denervation of the gastrocnemius muscle: an experimental study.

PubMed

Askar, I; Sabuncuoglu, B T; Yormuk, E; Saray, A

2001-07-01

In nerve injuries, if it is not possible to reinnervate muscle by using neurorrhaphy and nerve grafting technique, reinnervation should be provided by the use of neuroization-directly implanting motor nerve into muscle. A comparative study of three techniques of neurotization is presented in rabbits. In this experimental study, a total of 40 white New Zealand rabbits were used and divided into four groups, each including 10 rabbits. In the first group (control--Group 1), only surgical exposure of the gastrocnemius muscle, main muscle nerve (tibial nerve), and peroneal nerve was done, without any injury to the nerves. In the second group (direct neurotization group--Group 2), the tibial nerve was transected, and the peroneal nerve, which had already been divided into fascicles, was implanted into the lateral head of the gastrocnemius muscle aneural zone. In the third group (dual neurotization group--Group 3), the tibial nerve which had been transected and re-anastomosed, and the peroneal nerve were implanted into the lateral head of the gastrocnemius muscle. In the last experimental group (hyperneurotization group--Group 4), fascicles of the peroneal nerve were implanted into the lateral head of the gastrocnemius, preserving the tibial nerve. Six months later, changes in the histologic pattern and the functional recovery of the gastrocnemius muscle were investigated. It was found that functional recovery was achieved in all neurotization groups. Groups with the tibial nerve transected had less muscular weights than those of groups with the tibial nerve intact. EMG recordings showed that polyphasic and late potentials were frequently seen in groups with the tibial nerve transected. Degeneration and regeneration of myofibrils was observed in such groups as well. New motor end-plates, including vesicles, were formed in a scattered manner in all neurotization groups. As a result, the authors conclude that direct and dual neurotization techniques are useful in peripheral nerve injuries, if it is not possible to reinnervate muscle by using neurorraphy and nerve grafting, and that there is no suggested superiority among these techniques.

FAST CP: protocol of a randomised controlled trial of the efficacy of a 12-week combined Functional Anaerobic and Strength Training programme on muscle properties and mechanical gait deficiencies in adolescents and young adults with spastic-type cerebral palsy

PubMed Central

Gillett, Jarred G; Lichtwark, Glen A; Boyd, Roslyn N; Barber, Lee A

2015-01-01

Introduction Individuals with cerebral palsy (CP) have muscles that are smaller, weaker and more resistant to stretch compared to typically developing people. Progressive resistance training leads to increases in muscle size and strength. In CP, the benefits of resistance training alone may not transfer to improve other activities such as walking; however, the transfer of strength improvements to improved mobility may be enhanced by performing training that involves specific functional tasks or motor skills. This study aims to determine the efficacy of combined functional anaerobic and strength training in (1) influencing muscle strength, structure and function and (2) to determine if any changes in muscle strength and structure following training impact on walking ability and gross motor functional capacity and performance in the short (following 3 months of training) and medium terms (a further 3 months post-training). Methods and analysis 40 adolescents and young adults with CP will be recruited to undertake a 12-week training programme. The training programme will consist of 3×75 min sessions per week, made up of 5 lower limb resistance exercises and 2–3 functional anaerobic exercises per session. The calf muscles will be specifically targeted, as they are the most commonly impacted muscles in CP and are a key muscle group involved in walking. If, as we believe, muscle properties change following combined strength and functional training, there may be long-term benefits of this type of training in slowing the deterioration of muscle function in people with spastic-type CP. Ethics and dissemination Ethical approval has been obtained from the ethics committees at The University of Queensland (2014000066) and Children's Health Queensland (HREC/15/QRCH/30). The findings will be disseminated by publications in peer-reviewed journals, conferences and local research organisations’ media. Trial registration number Australian and New Zealand Clinical Trials Registry (ACTRN12614001217695). PMID:26116614

Dissection of a single rat muscle-tendon complex changes joint moments exerted by neighboring muscles: implications for invasive surgical interventions.

PubMed

Maas, Huub; Baan, Guus C; Huijing, Peter A

2013-01-01

The aim of this paper is to investigate mechanical functioning of a single skeletal muscle, active within a group of (previously) synergistic muscles. For this purpose, we assessed wrist angle-active moment characteristics exerted by a group of wrist flexion muscles in the rat for three conditions: (i) after resection of the upper arm skin; (ii) after subsequent distal tenotomy of flexor carpi ulnaris muscle (FCU); and (iii) after subsequent freeing of FCU distal tendon and muscle belly from surrounding tissues (MT dissection). Measurements were performed for a control group and for an experimental group after recovery (5 weeks) from tendon transfer of FCU to extensor carpi radialis (ECR) insertion. To assess if FCU tenotomy and MT dissection affects FCU contributions to wrist moments exclusively or also those of neighboring wrist flexion muscles, these data were compared to wrist angle-moment characteristics of selectively activated FCU. FCU tenotomy and MT dissection decreased wrist moments of the control group at all wrist angles tested, including also angles for which no or minimal wrist moments were measured when activating FCU exclusively. For the tendon transfer group, wrist flexion moment increased after FCU tenotomy, but to a greater extent than can be expected based on wrist extension moments exerted by selectively excited transferred FCU. We conclude that dissection of a single muscle in any surgical treatment does not only affect mechanical characteristics of the target muscle, but also those of other muscles within the same compartment. Our results demonstrate also that even after agonistic-to-antagonistic tendon transfer, mechanical interactions with previously synergistic muscles do remain present.

Chronic clenbuterol treatment compromises force production without directly altering skeletal muscle contractile machinery

PubMed Central

Py, G; Ramonatxo, C; Sirvent, P; Sanchez, A M J; Philippe, A G; Douillard, A; Galbès, O; Lionne, C; Bonnieu, A; Chopard, A; Cazorla, O; Lacampagne, A; Candau, R B

2015-01-01

Clenbuterol is a β2-adrenergic receptor agonist known to induce skeletal muscle hypertrophy and a slow-to-fast phenotypic shift. The aim of the present study was to test the effects of chronic clenbuterol treatment on contractile efficiency and explore the underlying mechanisms, i.e. the muscle contractile machinery and calcium-handling ability. Forty-three 6-week-old male Wistar rats were randomly allocated to one of six groups that were treated with either subcutaneous equimolar doses of clenbuterol (4 mg kg−1 day−1) or saline solution for 9, 14 or 21 days. In addition to the muscle hypertrophy, although an 89% increase in absolute maximal tetanic force (Po) was noted, specific maximal tetanic force (sPo) was unchanged or even depressed in the slow twitch muscle of the clenbuterol-treated rats (P < 0.05). The fit of muscle contraction and relaxation force kinetics indicated that clenbuterol treatment significantly reduced the rate constant of force development and the slow and fast rate constants of relaxation in extensor digitorum longus muscle (P < 0.05), and only the fast rate constant of relaxation in soleus muscle (P < 0.05). Myofibrillar ATPase activity increased in both relaxed and activated conditions in soleus (P < 0.001), suggesting that the depressed specific tension was not due to the myosin head alteration itself. Moreover, action potential-elicited Ca2+ transients in flexor digitorum brevis fibres (fast twitch fibres) from clenbuterol-treated animals demonstrated decreased amplitude after 14 days (−19%, P < 0.01) and 21 days (−25%, P < 0.01). In conclusion, we showed that chronic clenbuterol treatment reduces contractile efficiency, with altered contraction and relaxation kinetics, but without directly altering the contractile machinery. Lower Ca2+ release during contraction could partially explain these deleterious effects. PMID:25656230

Central and peripheral cardiovascular responses to electrically induced and voluntary leg exercise

NASA Technical Reports Server (NTRS)

Saltin, B.; Strange, S.; Bangsbo, J.; Kim, C. K.; Duvoisin, M.; Hargens, A.; Gollnick, P. D.

1990-01-01

With long missions in space countermeasures have to be used to secure safe operations in space and a safe return to Earth. Exercises of various forms have been used, but the question has arisen whether electrically induced contractions of muscle especially sensitive to weightlessness and crucial for man's performance would aid in maintaining their optimal function. The physiological responses both to short term and prolonged dynamic exercise performed either voluntarily or induced by electrical stimulation were considered. The local and systemic circulatory responses were similar for the voluntary and electrically induced contractions. The metabolic response was slightly more pronounced with electrical stimulation. This could be a reflection of not only slow twitch (type 1) but also fast twitch (type 2) fibers being recruited when the contractions were induced electrically. Intramuscular pressure recordings indicated that the dominant fraction of the muscle group was engaged regardless of mode of activation. Some 70 percent of the short term peak voluntary exercise capacity could be attained with electrical stimulation. Thus, electrically induced contractions of specific muscle groups should indeed be considered as an efficient countermeasure.

Developmental and adult-specific processes contribute to de novo neuromuscular regeneration in the lizard tail.

PubMed

Tokuyama, Minami A; Xu, Cindy; Fisher, Rebecca E; Wilson-Rawls, Jeanne; Kusumi, Kenro; Newbern, Jason M

2018-01-15

Peripheral nerves exhibit robust regenerative capabilities in response to selective injury among amniotes, but the regeneration of entire muscle groups following volumetric muscle loss is limited in birds and mammals. In contrast, lizards possess the remarkable ability to regenerate extensive de novo muscle after tail loss. However, the mechanisms underlying reformation of the entire neuromuscular system in the regenerating lizard tail are not completely understood. We have tested whether the regeneration of the peripheral nerve and neuromuscular junctions (NMJs) recapitulate processes observed during normal neuromuscular development in the green anole, Anolis carolinensis. Our data confirm robust axonal outgrowth during early stages of tail regeneration and subsequent NMJ formation within weeks of autotomy. Interestingly, NMJs are overproduced as evidenced by a persistent increase in NMJ density 120 and 250 days post autotomy (DPA). Substantial Myelin Basic Protein (MBP) expression could also be detected along regenerating nerves indicating that the ability of Schwann cells to myelinate newly formed axons remained intact. Overall, our data suggest that the mechanism of de novo nerve and NMJ reformation parallel, in part, those observed during neuromuscular development. However, the prolonged increase in NMJ number and aberrant muscle differentiation hint at processes specific to the adult response. An examination of the coordinated exchange between peripheral nerves, Schwann cells, and newly synthesized muscle of the regenerating neuromuscular system may assist in the identification of candidate molecules that promote neuromuscular recovery in organisms incapable of a robust regenerative response. Copyright © 2017 Elsevier Inc. All rights reserved.

Muscle-specific deletion of Prkaa1 enhances skeletal muscle lipid accumulation in mice fed a high-fat diet.

PubMed

Wu, Weiche; Xu, Ziye; Zhang, Ling; Liu, Jiaqi; Feng, Jie; Wang, Xinxia; Shan, Tizhong; Wang, Yizhen

2018-05-01

Excessive intramyocellular triacylglycerols (IMTGs, muscle lipids) are associated with the abnormal energy metabolism and insulin resistance of skeletal muscle. AMP-activated protein kinase (AMPK), a crucial cellular energy sensor, consists of α, β and γ subunits. Researchers have not clearly determined whether Prkaa1 (also known as AMPKα1) affects IMTG accumulation in skeletal muscle. Here, we show an important role of Prkaa1 in skeletal muscle lipid metabolism. Deletion of muscle Prkaa1 leads to the delayed development of skeletal muscles but does not affect glucose tolerance or insulin sensitivity in animals fed a normal diet. Notably, when animals are fed a high-fat diet, the skeletal muscle of muscle-specific Prkaa1 knockout mice accumulates more lipids than the skeletal muscle of wild-type (WT) mice, with concomitant upregulation of adipogenic gene expressions and downregulation of the expression of genes associated with mitochondrial oxidation. Muscle-specific Prkaa1 ablation also results in hyperlipidemia, which may contribute to the increased IMTG levels. Furthermore, Prkaa1 deletion activates skeletal muscle mTOR signalling, which has a central role in lipid metabolism and mitochondrial oxidation. Collectively, our study provides new insights into the role of Prkaa1 in skeletal muscle. This knowledge may contribute to the treatment of related metabolic diseases.

Unstable rocker shoes promote recovery from marathon-induced muscle damage in novice runners.

PubMed

Nakagawa, K; Inami, T; Yonezu, T; Kenmotsu, Y; Narita, T; Kawakami, Y; Kanosue, K

2018-02-01

We recently reported that wearing unstable rocker shoes (Masai Barefoot Technology: MBT) may enhance recovery from marathon race-induced fatigue. However, this earlier study only utilized a questionnaire. In this study, we evaluated MBT utilizing objective physiological measures of recovery from marathon-induced muscle damages. Twenty-five university student novice runners were divided into two groups. After running a full marathon, one group wore MBT shoes (MBT group), and the control group (CON) wore ordinary shoes daily for 1 week following the race. We measured maximal isometric joint torque, muscle hardness (real time tissue elastography of the strain ratio) in the lower limb muscles before, immediately after, and 1, 3, and 8 days following the marathon. We calculated the magnitude of recovery by observing the difference in each value between the first measurement and the latter measurements. Results showed that isometric torques in knee flexion recovered at the first day after the race in the MBT group while it did not recover even at the eighth day in the CON group. Muscle hardness in the gastrocnemius and vastus lateralis showed enhanced recovery in the MBT group in comparison with the CON group. Also for muscle hardness in the tibialis anterior and biceps femoris, the timing of recovery was delayed in the CON group. In conclusion, wearing MBT shoes enhanced recovery in lower leg and thigh muscles from muscle damage induced by marathon running. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Atrogin-1, a muscle-specific F-box protein highly expressed during muscle atrophy

NASA Technical Reports Server (NTRS)

Gomes, M. D.; Lecker, S. H.; Jagoe, R. T.; Navon, A.; Goldberg, A. L.

2001-01-01

Muscle wasting is a debilitating consequence of fasting, inactivity, cancer, and other systemic diseases that results primarily from accelerated protein degradation by the ubiquitin-proteasome pathway. To identify key factors in this process, we have used cDNA microarrays to compare normal and atrophying muscles and found a unique gene fragment that is induced more than ninefold in muscles of fasted mice. We cloned this gene, which is expressed specifically in striated muscles. Because this mRNA also markedly increases in muscles atrophying because of diabetes, cancer, and renal failure, we named it atrogin-1. It contains a functional F-box domain that binds to Skp1 and thereby to Roc1 and Cul1, the other components of SCF-type Ub-protein ligases (E3s), as well as a nuclear localization sequence and PDZ-binding domain. On fasting, atrogin-1 mRNA levels increase specifically in skeletal muscle and before atrophy occurs. Atrogin-1 is one of the few examples of an F-box protein or Ub-protein ligase (E3) expressed in a tissue-specific manner and appears to be a critical component in the enhanced proteolysis leading to muscle atrophy in diverse diseases.

Effect of dietary choline levels on growth performance, lipid deposition and metabolism in juvenile yellow catfish Pelteobagrus fulvidraco.

PubMed

Luo, Zhi; Wei, Chuan-Chuan; Ye, Han-Mei; Zhao, Hai-Ping; Song, Yu-Feng; Wu, Kun

2016-12-01

The present experiment was conducted to determine the effect and mechanism of dietary choline levels on growth performance and lipid deposition of yellow catfish Pelteobagrus fulvidraco. Dietary choline was included at three levels of 239.2 (control (without extra choline addition), 1156.4 and 2273.6mg choline per kg diet, respectively) and fed to yellow catfish (mean initial weight: 3.45±0.02g mean±standard errors of mean (SEM)) for 8weeks. Fish fed the diet containing 1156.4mgkg -1 choline showed the higher weight gain (WG), specific growth rate (SGR) and feed intake (FI), but the lower feed conversion rate (FCR), than those in control and highest choline group. Hepatosomatic index (HSI) and hepatic lipid content declined with increasing dietary choline levels. Muscle lipid content was the lowest for fish fed adequate choline diets and showed no significant difference between other two groups. Choline contents in liver and muscle increased with increasing dietary choline levels. Dietary choline levels significantly influenced mRNA levels of genes involved in lipid homeostasis in muscle and liver, such as CTP:phosphocholine cytidylyltransferase a (CCTa), phosphatidylethanolamine N-methyl-transferase (PEMT), microsomal triglyceride transfer protein (MTP), apolipoprotein b (APOBb), apolipoprotein E (ApoE) and lipoprotein lipase (LPL), and effects of dietary choline levels on lipid deposition and metabolism were tissue-specific. Different responses of these genes at the mRNA levels partially explained the profiles of lipid deposition in liver and muscle for fish fed different choline diets. To our knowledge, this is the first to explore the effect of dietary choline level on mRNA expression of these genes, which provides new insights into choline nutrition in fish. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of changes in dietary fatty acids on isolated skeletal muscle functions in rats.

PubMed

Ayre, K J; Hulbert, A J

1996-02-01

The effects of manipulating dietary levels of essential polyunsaturated fatty acids on the function of isolated skeletal muscles in male Wistar rats were examined. Three isoenergetic diets were used: an essential fatty acid-deficient diet (EFAD), a diet high in essential (n-6) fatty acids [High (n-6)], and a diet enriched with essential (n-3) fatty acids [High (n-3)]. After 9 wk, groups of rats on each test diet were fed a stock diet of laboratory chow for a further 6 wk. Muscle function was examined by using a battery of five tests for soleus (slow twitch) and extensor digitorum longus (EDL; fast twitch). Tests included single muscle twitches, sustained tetanic contractions, posttetanic potentiation, sustained high-frequency stimulation, and intermittent low-frequency stimulation. Results for muscles from the High (n-6) and High (n-3) groups were very similar. However, the EFAD diet resulted in significantly lower muscular tensions and reduced response times compared with the High (n-6) and High (n-3) diets. Peak twitch tension in soleus muscles was 16-21% less in the EFAD group than in the High (n-6) and High (n-3) groups, respectively [analysis of variance (ANOVA), P < 0.01). During high-frequency stimulation, EDL muscles from the EFAD rats fatigued 32% more quickly (ANOVA, P < 0.01)]. Also, twitch contraction and half-relaxation times were significantly 5-7% reduced in the EFAD group (ANOVA, P < 0.01). During intermittent low-frequency stimulation, soleus muscles from the EFAD group generated 25-28% less tension than did the other groups (ANOVA, P < 0.01), but in EDL muscles from the EFAD group, endurance was 20% greater than in the High (n-6) group (ANOVA, P < 0.05). After 6 wk on the stock diet, there were no longer any differences between the dietary groups. Manipulation of dietary fatty acids results in significant, but reversible, effects in muscles of rats fed an EFAD diet.

38 CFR 3.350 - Special monthly compensation ratings.

Code of Federal Regulations, 2013 CFR

2013-07-01

... after discharge was required for the correction of a specific injury caused by a preceding operation in... both buttocks shall be deemed to exist when there is severe damage by disease or injury to muscle group... prosthetic appliance; (3) Anatomical loss of one arm so near the shoulder as to prevent use of a prosthetic...

38 CFR 3.350 - Special monthly compensation ratings.

Code of Federal Regulations, 2014 CFR

2014-07-01

... after discharge was required for the correction of a specific injury caused by a preceding operation in... both buttocks shall be deemed to exist when there is severe damage by disease or injury to muscle group... prosthetic appliance; (3) Anatomical loss of one arm so near the shoulder as to prevent use of a prosthetic...

38 CFR 3.350 - Special monthly compensation ratings.

Code of Federal Regulations, 2012 CFR

2012-07-01

... after discharge was required for the correction of a specific injury caused by a preceding operation in... both buttocks shall be deemed to exist when there is severe damage by disease or injury to muscle group... prosthetic appliance; (3) Anatomical loss of one arm so near the shoulder as to prevent use of a prosthetic...

Cancer-Specific Mortality Relative to Engagement in Muscle-Strengthening Activities and Lower Extremity Strength.

PubMed

Dankel, Scott J; Loenneke, Jeremy P; Loprinzi, Paul D

2018-02-01

Skeletal muscle strength and engagement in muscle-strengthening activities are each inversely associated with all-cause mortality; however, less is known on their relationship with cancer-specific mortality. Data from the 1999-2002 National Health and Nutrition Examination Survey were used assessing 2773 individuals aged 50 years or older. Individuals being dichotomized at the 75th percentile for knee extensor strength, and engagement in muscle-strengthening activities was acquired through self-report with ≥2 sessions per week were classified as meeting guidelines. With respect to cancer-specific mortality, individuals in the upper quartile for muscle strength were at a 50% reduced risk (hazard ratio = 0.50; 95% confidence interval, 0.29-0.85; P = .01) and those meeting muscle-strengthening activities were at a nonsignificant 8% reduced risk (hazard ratio = 0.92; 95% confidence interval, 0.45-1.86, P = .81) of cancer-specific mortality after adjusting for covariates. Clinicians should routinely assess lower extremity strength and promote engagement in muscle-strengthening activities aimed at increasing muscle strength.

Prevalence and clinical aspects of immigrants with myasthenia gravis in northern Europe.

PubMed

Boldingh, Marion Ingeborg; Maniaol, Angelina; Brunborg, Cathrine; Dekker, Luuk; Lipka, Alexander; Harmen Niks, Erik; Verschuuren, Jan; Tallaksen, Chantal

2017-06-01

Multiethnic studies can provide etiological clues toward the genetic and environmental influence of a disease. The aim of this study was to determine prevalence and clinical features of myasthenia gravis (MG) in immigrants compared with native patients in 2 population-based cohorts. This cross-sectional study included 843 MG patients (375 from Norway and 468 from the Netherlands). Ethnic background was defined by questionnaires. Among the participating MG patients, 163 of 843 (19.3%) were first or second generation immigrants, mainly from Europe, Asia, and South America. No marked prevalence differences were found between immigrants and native ethnic groups. MG with muscle specific kinase antibodies and MG with thymoma were more frequent in Asian MG immigrants compared with other ethnic groups (8% vs. 0-4%; P < 0.001 and 21% vs. 6-10%; P < 0.001), respectively. Our findings indicate that Asian immigrant MG patients carry genetic factors or environmental/lifestyle factors which contribute to their specific phenotype, even after migration. Muscle Nerve 55: 819-827, 2017. © 2016 Wiley Periodicals, Inc.

Reinnervation of the lateral gastrocnemius and soleus muscles in the rat by their common nerve.

PubMed Central

Gillespie, M J; Gordon, T; Murphy, P R

1986-01-01

To determine whether there is any specificity of regenerating nerves for their original muscles, the common lateral gastrocnemius soleus nerve (l.g.s.) innervating the fast-twitch lateral gastrocnemius (l.g.) and slow-twitch soleus muscles was sectioned in the hind limb of twenty adult rats. The proximal nerve stump was sutured to the dorsal surface of the l.g. muscle and 4-14 months later, the contractile properties of the reinnervated l.g. and soleus muscles and their single motor units were studied by dissection and stimulation of the ventral root filaments. Contractile properties of normal contralateral muscles were examined for comparison and motor units were isolated in l.g. and soleus muscles for study in a group of untreated animals. Measurement of time and rate parameters of maximal twitch and tetanic contractions showed that the rate of development of force increased significantly in reinnervated soleus muscles and approached the speed of l.g. muscles but rate of relaxation did not change appreciably. In reinnervated l.g. muscles, contraction speed was similar to normal l.g. muscles but relaxation rate declined toward the rates of relaxation in control soleus muscles. After reinnervation by the common l.g.s. nerve, the proportion of slow motor units in l.g. increased from 10 to 31% and decreased in soleus from 80 to 31%. The relative proportions of fast and slow motor units in each muscle were the same as the proportions of fast and slow units in the normal l.g. and soleus muscles combined. It was concluded that fast and slow muscles do not show any preference for their former nerves and that the change in the force profile of the reinnervated muscles is indicative of the relative proportions of fast and slow motor units: fast units dominate the contraction phase and slow units the relaxation phase of twitch and tetanic contractions of the muscle. PMID:3723414

The effects of whole body vibration combined computerized postural control training on the lower extremity muscle activity and cerebral cortex activity in stroke patients.

PubMed

Uhm, Yo-Han; Yang, Dae-Jung

2018-02-01

[Purpose] The purpose of this study was to examine the effect of computerized postural control training using whole body vibration on lower limb muscle activity and cerebral cortical activation in acute stroke patients. [Subjects and Methods] Thirty stroke patients participated and were divided into groups of 10, a group of the computerized postural control training using whole body vibration (Group I), the computerized postural control training combined with aero step (Group II) and computerized postural control training (Group III). MP100 was used to measure lower limb muscle activity, and QEEG-8 was used to measure cerebral cortical activation. [Results] Comparison of muscle activity and cerebral cortical activation before and after intervention between groups showed that Group I had significant differences in lower limb muscle activity and cerebral cortical activation compared to Groups II and III. [Conclusion] This study showed that whole body vibration combined computerized postural control training is effective for improving muscle activity and cerebral cortex activity in stroke patients.

Effect of depressor septi nasi muscle activity on nasal lengthening with time.

PubMed

Beiraghi-Toosi, Arash; Rezaei, Ezzatollah; Jabbari Nooghabi, Mehdi; Izadpanah, Shahram

2013-10-01

The depressor septi nasi (DSN) muscle is an important muscle in nose dynamics. Its hyperactivity causes smile deformity including nasal tip depression. The nasal tip of individuals with a hyperactive DSN muscle depresses repeatedly while they are speaking and smiling. This may result in nasal lengthening as they age. Pairs of cases consisting of a child and one of his or her parents were studied in two groups: case group (with DSN muscle hyperactivity) and the control group (with DSN muscle inactivity in both child and parent). Nasal length from nasion to tip and facial length from nasion to menton were measured during repose and during smiling. This study investigated 80 pairs of children and parents. In both groups, a significant linear correlation between the nasal length of the parent and the child was found. In both groups (case and control), the nasal length of the child differed significantly from that of the parent. The increase in the nasal length of the parents compared with the children was greater in the control group. This study demonstrated that nasal length increases with age and that DSN muscle hyperactivity is not an effective factor in this increase. This unpredictable result may affect the presumption that patients with DSN muscle hyperactivity will have longer noses in the future. Long-term prospective studies investigating cohort groups are required to clarify the variables affecting nasal lengthening with aging, and interventional studies are needed to examine the effects of DSN muscle resection on this phenomenon.

[Characteristics of opening movement in patients with unilateral mastication].

PubMed

Jia, Ling; Wang, Yun; Wang, Mengya

2016-08-01

To analyze characteristics of mandibular movement in patients with unilateral mastication.
 Undergraduate students in oral medicine from Grade 2011 and 2012 in Wannan Medical College were enrolled for this study by cluster sampling method, which include 30 people with unilateral mastication and 30 people with bilateral mastication. The surface electromyogram (sEMG) of masseter muscle and anterovent of digastric muscle were recorded and the trajectory of mandibular incisor point was recorded simultaneously in the maximum opening and closing movement. The results were analyzed by SPSS 19.0 software.
 Average electrical peak of left anterior digastric muscle and right anterior digastric muscle in the unilateral chewing group was lower than that in the bilateral chewing group (P<0.05). The jaw tangent point trajectory was separate in the unilateral chewing group. There were significant differences at the opening type between the 2 groups. The vertical displacement and the sagittal displacement in the unilateral chewing group were significantly lower than those in the bilateral chewing group (P<0.01). There was significant positive correlation between the average peak potential of masseter muscle and displacement on the right side.
 Average electrical peak of left masseter muscle, left anterior digastric muscle, and right anterior digastric muscle decreases in the unilateral chewing group. Jaw tracking in most people deflects to the working side. Opening and closing jaw tracking is separate in 50% unilateral chewing individuals with the decreased opening degree. Unilateral chewing leads to changes in muscle performance accompanied by trajectory anomalies.

Temporal proteomic response to acute heat stress in the porcine muscle sarcoplasm.

PubMed

Cruzen, S M; Baumgard, L H; Gabler, N K; Pearce, S C; Lonergan, S M

2017-09-01

Heat stress (HS) is an important topic in the swine industry, costing hundreds of millions of dollars in economic losses annually, figures that could easily rise in light of global climate change. Muscle biology during HS is particularly important given skeletal muscle's large proportion to the body and its ultimate conversion to meat. Here we report the proteomic changes that occur during acute HS (37°C and 40% relative humidity) lasting 2, 4, or 6 h in the muscle sarcoplasm of growing pigs in comparison with 6 h of thermal neutral (TN; 21°C and 70% relative humidity) conditions ( = 8 per treatment). The red and white areas of the semitendinosus muscle were used to compare the differential effects of HS on oxidative or glycolytic muscles. The results support the hypothesis of proteomic profile differences between the acute HS and TN groups. Altered abundance ( < 0.05) of several proteins occurred in as little as 2 h of HS, affecting metabolism, cell structure, and chaperone, antioxidant, and proteolytic activity. We determined that the muscle HS response is both fiber type and time specific. Overall, more differences were observed in the red semitendinosus than in the white semitendinosus, although the time point at which differences were observed varied. These data show that as little as 2 h of HS has measurable effects on muscle proteins, indicating that acute HS has the potential to impair muscle function and growth.

Associations of knee muscle force, bone malalignment, and knee-joint laxity with osteoarthritis in elderly people.

PubMed

Nakagawa, Kazumasa; Maeda, Misako

2017-03-01

[Purpose] From the viewpoint of prevention of knee osteoarthritis, the aim of this study was to verify how muscle strength and joint laxity are related to knee osteoarthritis. [Subjects and Methods] The study subjects consisted of 90 community-dwelling elderly people aged more than 60 years (22 males, 68 females). Femorotibial angle alignment, knee joint laxity, knee extensors and flexor muscle strengths were measured in all subjects. In addition, the subjects were divided into four groups based on the presence of laxity and knee joint deformation, and the muscle strength values were compared. [Results] There was no significant difference in knee extensor muscle strength among the four groups. However, there was significant weakness of the knee flexor muscle in the group with deformation and laxity was compared with the group without deformation and laxity. [Conclusion] Decreased knee flexor muscle strengths may be involved in knee joint deformation. The importance of muscle strength balance was also considered.

Use of latissimus dorsi muscle onlay patch alternative to acellular dermal matrix in implant-based breast reconstruction

PubMed Central

Lee, Jeeyeon

2015-01-01

Background An acellular dermal matrix (ADM) is applied to release the surrounding muscles and prevent dislocation or rippling of the implant. We compared implant-based breast reconstruction using the latissimus dorsi (LD) muscle, referred to as an “LD muscle onlay patch,” with using an ADM. Method A total of 56 patients (60 breasts) underwent nipple sparing mastectomy with implant-based breast reconstruction using an ADM or LD muscle onlay patch. Cosmetic outcomes were assessed 4 weeks after chemotherapy or radiotherapy, and statistical analyses were performed. Results Mean surgical time and hospital stay were significantly longer in the LD muscle onlay patch group than the ADM group. However, there were no statistically significant differences between groups in postoperative complications. Cosmetic outcomes for breast symmetry and shape were higher in the LD muscle onlay patch group. Conclusions Implant-based breast reconstruction with an LD muscle onlay patch would be a feasible alternative to using an ADM. PMID:26161312

More than a bystander: the contributions of intrinsic skeletal muscle defects in motor neuron diseases

PubMed Central

Boyer, Justin G.; Ferrier, Andrew; Kothary, Rashmi

2013-01-01

Spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), and spinal-bulbar muscular atrophy (SBMA) are devastating diseases characterized by the degeneration of motor neurons. Although the molecular causes underlying these diseases differ, recent findings have highlighted the contribution of intrinsic skeletal muscle defects in motor neuron diseases. The use of cell culture and animal models has led to the important finding that muscle defects occur prior to and independently of motor neuron degeneration in motor neuron diseases. In SMA for instance, the muscle specific requirements of the SMA disease-causing gene have been demonstrated by a series of genetic rescue experiments in SMA models. Conditional ALS mouse models expressing a muscle specific mutant SOD1 gene develop atrophy and muscle degeneration in the absence of motor neuron pathology. Treating SBMA mice by over-expressing IGF-1 in a skeletal muscle-specific manner attenuates disease severity and improves motor neuron pathology. In the present review, we provide an in depth description of muscle intrinsic defects, and discuss how they impact muscle function in these diseases. Furthermore, we discuss muscle-specific therapeutic strategies used to treat animal models of SMA, ALS, and SBMA. The study of intrinsic skeletal muscle defects is crucial for the understanding of the pathophysiology of these diseases and will open new therapeutic options for the treatment of motor neuron diseases. PMID:24391590

Determination of the anti-inflammatory and cytoprotective effects of l-glutamine and l-alanine, or dipeptide, supplementation in rats submitted to resistance exercise.

PubMed

Raizel, Raquel; Leite, Jaqueline Santos Moreira; Hypólito, Thaís Menezes; Coqueiro, Audrey Yule; Newsholme, Philip; Cruzat, Vinicius Fernandes; Tirapegui, Julio

2016-08-01

We evaluated the effects of chronic oral supplementation with l-glutamine and l-alanine in their free form or as the dipeptide l-alanyl-l-glutamine (DIP) on muscle damage, inflammation and cytoprotection, in rats submitted to progressive resistance exercise (RE). Wistar rats (n 8/group) were submitted to 8-week RE, which consisted of climbing a ladder with progressive loads. In the final 21 d before euthanasia, supplements were delivered in a 4 % solution in drinking water. Glutamine, creatine kinase (CK), lactate dehydrogenase (LDH), TNF-α, specific IL (IL-1β, IL-6 and IL-10) and monocyte chemoattractant protein-1 (MCP-1) levels were evaluated in plasma. The concentrations of glutamine, TNF-α, IL-6 and IL-10, as well as NF-κB activation, were determined in extensor digitorum longus (EDL) skeletal muscle. HSP70 level was assayed in EDL and peripheral blood mononuclear cells (PBMC). RE reduced glutamine concentration in plasma and EDL (P<0·05 v. sedentary group). However, l-glutamine supplements (l-alanine plus l-glutamine (GLN+ALA) and DIP groups) restored glutamine levels in plasma (by 40 and 58 %, respectively) and muscle (by 93 and 105 %, respectively). GLN+ALA and DIP groups also exhibited increased level of HSP70 in EDL and PBMC, consistent with the reduction of NF-κB p65 activation and cytokines in EDL. Muscle protection was also indicated by attenuation in plasma levels of CK, LDH, TNF-α and IL-1β, as well as an increase in IL-6, IL-10 and MCP-1. Our study demonstrates that chronic oral l-glutamine treatment (given with l-alanine or as dipeptide) following progressive RE induces cyprotective effects mediated by HSP70-associated responses to muscle damage and inflammation.

Specific Adaptations in Performance and Muscle Architecture After Weighted Jump-Squat vs. Body Mass Squat Jump Training in Recreational Soccer Players.

PubMed

Coratella, Giuseppe; Beato, Marco; Milanese, Chiara; Longo, Stefano; Limonta, Eloisa; Rampichini, Susanna; Cè, Emiliano; Bisconti, Angela V; Schena, Federico; Esposito, Fabio

2018-04-01

Coratella, G, Beato, M, Milanese, C, Longo, S, Limonta, E, Rampichini, S, Cè, E, Bisconti, AV, Schena, F, and Esposito, F. Specific adaptations in performance and muscle architecture after weighted jump-squat vs. body mass squat jump training in recreational soccer players. J Strength Cond Res 32(4): 921-929, 2018-The aim of the present study was to compare the effects of weighted jump-squat training (WJST) vs. body mass squat jump training (BMSJT) on quadriceps' muscle architecture, lower-limb lean-mass (LM) and muscle strength, performance in change of direction (COD), and sprint and jump in recreational soccer players. Forty-eight healthy soccer players participated in an offseason randomized controlled trial. Before and after an 8-week training intervention, vastus lateralis pennation angle, fascicle length, muscle thickness, LM, squat 1RM, quadriceps and hamstrings isokinetic peak torque, agility T-test, 10-and 30-m sprints, and squat-jump (SJ) were measured. Although similar increases were observed in muscle thickness, fascicle length increased more in WJST (Effect size [ES] = 1.18, 0.82-1.54) than in BMSJT (ES = 0.54, 0.40-0.68), and pennation angle increased only in BMSJT (ES = 1.03, 0.78-1.29). Greater increases in LM were observed in WJST (ES = 0.44, 0.29-0.59) than in BMSJT (ES = 0.21, 0.07-0.37). The agility T-test (ES = 2.95, 2.72-3.18), 10-m (ES = 0.52, 0.22-0.82), and 30-m sprints (ES = 0.52, 0.23-0.81) improved only in WJST, whereas SJ improved in BMSJT (ES = 0.89, 0.43-1.35) more than in WJST (ES = 0.30, 0.03-0.58). Similar increases in squat 1RM and peak torque occurred in both groups. The greater inertia accumulated within the landing phase in WJST vs. BMSJT has increased the eccentric workload, leading to specific eccentric-like adaptations in muscle architecture. The selective improvements in COD in WJST may be related to the increased braking ability generated by the enhanced eccentric workload.

The effects of running exercise on oxidative capacity and PGC-1α mRNA levels in the soleus muscle of rats with metabolic syndrome.

PubMed

Nagatomo, Fumiko; Fujino, Hidemi; Kondo, Hiroyo; Kouzaki, Motoki; Gu, Ning; Takeda, Isao; Tsuda, Kinsuke; Ishihara, Akihiko

2012-03-01

Skeletal muscles in animals with metabolic syndrome exhibit reduced oxidative capacity. We investigated the effects of running exercise on fiber characteristics, oxidative capacity, and mRNA levels in the soleus muscles of rats with metabolic syndrome [SHR/NDmcr-cp (cp/cp); CP]. We divided 5-week-old CP rats into non-exercise (CP) and exercise (CP-Ex) groups. Wistar-Kyoto rats (WKY) were used as the control group. CP-Ex rats were permitted voluntary exercise on running wheels for 10 weeks. Triglyceride levels were higher and adiponectin levels lower in the CP and CP-Ex groups than in the WKY group. However, triglyceride levels were lower and adiponectin levels higher in the CP-Ex group than in the CP group. The soleus muscles in CP-Ex rats contained only high-oxidative type I fibers, whereas those in WKY and CP rats contained type I, IIA, and IIC fibers. Muscle succinate dehydrogenase (SDH) activity was higher in the CP-Ex group than in the CP group; there was no difference in SDH activity between the WKY and CP-Ex groups. Muscle proliferator-activated receptor γ coactivator-1α (PGC-1α) mRNA levels were higher in the CP-Ex group than in the CP group; there was no difference in PGC-1α mRNA levels between the WKY and CP-Ex groups. In CP-Ex rats, longer running distance was associated with increased muscle SDH activity and PGC-1α mRNA levels. We concluded that running exercise restored decreased muscle oxidative capacity and PGC-1α mRNA levels and improved hypertriglyceridemia in rats with metabolic syndrome.

Fish-oil supplementation enhances the effects of strength training in elderly women.

PubMed

Rodacki, Cintia L N; Rodacki, André L F; Pereira, Gleber; Naliwaiko, Katya; Coelho, Isabela; Pequito, Daniele; Fernandes, Luiz Cléudio

2012-02-01

Muscle force and functional capacity generally decrease with aging in the older population, although this effect can be reversed, attenuated, or both through strength training. Fish oil (FO), which is rich in n-3 (omega-3) PUFAs, has been shown to play a role in the plasma membrane and cell function of muscles, which may enhance the benefits of training. The effect of strength training and FO supplementation on the neuromuscular system of the elderly has not been investigated. The objective was to investigate the chronic effect of FO supplementation and strength training on the neuromuscular system (muscle strength and functional capacity) of older women. Forty-five women (aged 64 ± 1.4 y) were randomly assigned to 3 groups. One group performed strength training only (ST group) for 90 d, whereas the others performed the same strength-training program and received FO supplementation (2 g/d) for 90 d (ST90 group) or for 150 d (ST150 group; supplemented 60 d before training). Muscle strength and functional capacity were assessed before and after the training period. No differences in the pretraining period were found between groups for any of the variables. The peak torque and rate of torque development for all muscles (knee flexor and extensor, plantar and dorsiflexor) increased from pre- to posttraining in all groups. However, the effect was greater in the ST90 and ST150 groups than in the ST group. The activation level and electromechanical delay of the muscles changed from pre- to posttraining only for the ST90 and ST150 groups. Chair-rising performance in the FO groups was higher than in the ST group. Strength training increased muscle strength in elderly women. The inclusion of FO supplementation caused greater improvements in muscle strength and functional capacity.

Idiopathic Inflammatory Myopathies: A Review of the Classification and Impact of Pathogenesis

PubMed Central

Mandel, Dana E.; Malemud, Charles J.; Askari, Ali D.

2017-01-01

Idiopathic inflammatory myopathies (IIMs) are a group of autoimmune muscle diseases with significant morbidity and mortality. This review details and updates the pathogenesis and emerging importance of myositis-specific antibodies in the development of IIMs. An increase in the understanding of how these myositis-specific antibodies play a role in IIMs has led to the further categorization of IIMs from the traditional polymyositis versus dermatomyositis, to additional subcategories of IIMs such as necrotizing autoimmune myositis (NAM). The diagnosis of IIMs, including manual muscle testing, laboratory studies, and non-invasive imaging have become important in classifying IIM subtypes and for identifying disease severity. Treatment has evolved from an era where glucocorticoid therapy was the only option to a time now that includes traditional steroid-sparing agents along with immunoglobulin therapy and biologics, such as rituximab. PMID:28524083

Passive versus active stretching of hip flexor muscles in subjects with limited hip extension: a randomized clinical trial.

PubMed

Winters, Michael V; Blake, Charles G; Trost, Jennifer S; Marcello-Brinker, Toni B; Lowe, Lynne M; Garber, Matthew B; Wainner, Robert S

2004-09-01

Active stretching is purported to stretch the shortened muscle and simultaneously strengthen the antagonist muscle. The purpose of this study was to determine whether active and passive stretching results in a difference between groups at improving hip extension range of motion in patients with hip flexor muscle tightness. Thirty-three patients with low back pain and lower-extremity injuries who showed decreased range of motion, presumably due to hip flexor muscle tightness, completed the study. The subjects, who had a mean age of 23.6 years (SD = 5.3, range = 18-25), were randomly assigned to either an active home stretching group or a passive home stretching group. Hip extension range of motion was measured with the subjects in the modified Thomas test position at baseline and 3 and 6 weeks after the start of the study. Range of motion in both groups improved over time, but there were no differences between groups. The results indicate that passive and active stretching are equally effective for increasing range of motion, presumably due to increased flexibility of tight hip flexor muscles. Whether the 2 methods equally improve flexibility of other muscle groups or whether active stretching improves the function of the antagonist muscles is not known. Active and passive stretching both appeared to increase the flexibility of tight hip flexor muscles in patients with musculoskeletal impairments.

The Effect of Increasing Volume of Exercise on Activation Pattern of Vastus Medialis and Lateralis and its Correlation With Anterior Knee Pain in Karate Elites

PubMed Central

Safar Cherati, Afsaneh; Lotfian, Sara; Jamshidi, Aliashraf; Sanjari, Mohammad Ali; Razi, Mohammad

2016-01-01

Background The effects of exercise volume on the pattern of muscle activity is one of the most important factors in training management and injury risk reduction. In the lower limb, the quadriceps muscle which plays a determining role in performing the stance and other karate techniques could be injured in intensive exercise and may induce anterior knee pain in athletes. Objectives The aim of this study was to determine the relationship between training volume and muscle activity of vastus medialis and vastus lateralis and its association with anterior knee pain in karate elites. Patients and Methods Male and female athletes from national junior and cadet karate team (14 to 18 years) were invited to participate in the study at the beginning and the end of the training camps. Studies involved measurement of electromyographic muscle activity of vastus medialis and vastus lateralis in both lower extremities with surface electromyography device and assessment of movement by electrogoniometery. Muscle activity was recorded in three tests of dachi, walking up and walking down stairs. Simultaneously, anterior knee pain was evaluated using visual analogue scale and anterior knee pain scale questionnaire. Results Eight athletes of a total number of 23 reported increased ratings of pain in their right knees. No differences in muscle activity were observed in tests of Dachi and stairs between the groups with and without pain. Comparing Dachi task pattern at the beginning and end of training camps, there was no significant difference in pattern of biomechanical movement; however, reducing the amount of muscle activity in early and late phases of tasks was observed in electromyographic assessment. Conclusions The results showed that performing the same task after a six-week training period, less muscle activity was required in all phases in two groups of tasks, including karate-specific movement (dachi) and activities of daily living (up or down stairs). PMID:27826403

The Effect of Increasing Volume of Exercise on Activation Pattern of Vastus Medialis and Lateralis and its Correlation With Anterior Knee Pain in Karate Elites.

PubMed

Safar Cherati, Afsaneh; Lotfian, Sara; Jamshidi, Aliashraf; Sanjari, Mohammad Ali; Razi, Mohammad

2016-09-01

The effects of exercise volume on the pattern of muscle activity is one of the most important factors in training management and injury risk reduction. In the lower limb, the quadriceps muscle which plays a determining role in performing the stance and other karate techniques could be injured in intensive exercise and may induce anterior knee pain in athletes. The aim of this study was to determine the relationship between training volume and muscle activity of vastus medialis and vastus lateralis and its association with anterior knee pain in karate elites. Male and female athletes from national junior and cadet karate team (14 to 18 years) were invited to participate in the study at the beginning and the end of the training camps. Studies involved measurement of electromyographic muscle activity of vastus medialis and vastus lateralis in both lower extremities with surface electromyography device and assessment of movement by electrogoniometery. Muscle activity was recorded in three tests of dachi, walking up and walking down stairs. Simultaneously, anterior knee pain was evaluated using visual analogue scale and anterior knee pain scale questionnaire. Eight athletes of a total number of 23 reported increased ratings of pain in their right knees. No differences in muscle activity were observed in tests of Dachi and stairs between the groups with and without pain. Comparing Dachi task pattern at the beginning and end of training camps, there was no significant difference in pattern of biomechanical movement; however, reducing the amount of muscle activity in early and late phases of tasks was observed in electromyographic assessment. The results showed that performing the same task after a six-week training period, less muscle activity was required in all phases in two groups of tasks, including karate-specific movement (dachi) and activities of daily living (up or down stairs).

Establishment of a drug-induced rhabdomyolysis mouse model by co-administration of ciprofloxacin and atorvastatin.

PubMed

Matsubara, Akiko; Oda, Shingo; Akai, Sho; Tsuneyama, Koichi; Yokoi, Tsuyoshi

2018-07-01

Rhabdomyolysis is one of the serious side effects of ciprofloxacin (CPFX), a widely used antibacterial drug; and occasionally, acute kidney injury (AKI) occurs. Often, rhabdomyolysis has occurred in patients taking CPFX co-administered with statins. The purpose of this study is to establish a mouse model of drug-induced rhabdomyolysis by co-administration of CPFX and atorvastatin (ATV) and to clarify the mechanisms of its pathogenesis. C57BL/6J mice treated with L-buthionine-(S,R)-sulfoximine (BSO), a glutathione synthesis inhibitor, were orally administered with CPFX and ATV for 4 days. Plasma levels of creatinine phosphokinase (CPK) and aspartate aminotransferase (AST) were significantly increased in the CPFX and ATV-co-administered group. Histopathological examination of skeletal muscle observed degeneration in gastrocnemius muscle and an increased number of the satellite cells. Expressions of skeletal muscle-specific microRNA and mRNA in plasma and skeletal muscle, respectively, were significantly increased. The area under the curve (AUC) of plasma CPFX was significantly increased in the CPFX and ATV-co-administered group. Furthermore, cytoplasmic vacuolization and a positively myoglobin-stained region in kidney tissue and high content of myoglobin in urine were observed. These results indicated that AKI was induced by myoglobin that leaked from skeletal muscle. The established mouse model in the present study would be useful for predicting potential rhabdomyolysis risks in preclinical drug development. Copyright © 2018 Elsevier B.V. All rights reserved.

Pilates training improves 5-km run performance by changing metabolic cost and muscle activity in trained runners

PubMed Central

Finatto, Paula; Silva, Edson Soares Da; Okamura, Alexandre B.; Almada, Bruna P.; Oliveira, Henrique B.

2018-01-01

Purpose Strength training improves distance running economy and performance. This finding is based predominantly on maximal and explosive strength programmes applied to locomotor muscles, particularly on the lower limbs. It is not certain whether a minimization of metabolic cost (Cmet) and an improvement in running performance is feasible with strength training of the postural and trunk muscles. Methods Using kinematic, neuromuscular and metabolic measurements of running at two different speeds before and after a 12-week Pilates training programme, we tested the hypothesis that core training might improve the running Cmet and performance of trained runners. Thirty-two individuals were randomly assigned to the control group (CG, n = 16) or the Pilates group (PG, n = 16). Results Confirming our hypothesis, a significant improvement (p<0.05) was observed for running performance in the PG (pre: 25.65±0.4 min; post: 23.23±0.4 min) compared to the CG (pre: 25.33±0.58 min; post: 24.61±0.52 min). Similarly, the PG (4.33±0.07 J.kg-1.m-1) had better responses than the CG (4.71±0.11 J.kg-1.m-1) during post-training for Cmet. These findings were accompanied by decreased electromyographic activity of the postural muscles at submaximal running intensities in the PG. Conclusions Overall, these results provide a rationale for selecting strength training strategies that target adaptations on specific postural and locomotor muscles for trained distance runners. PMID:29561907

Pilates training improves 5-km run performance by changing metabolic cost and muscle activity in trained runners.

PubMed

Finatto, Paula; Silva, Edson Soares Da; Okamura, Alexandre B; Almada, Bruna P; Oliveira, Henrique B; Peyré-Tartaruga, Leonardo A

2018-01-01

Strength training improves distance running economy and performance. This finding is based predominantly on maximal and explosive strength programmes applied to locomotor muscles, particularly on the lower limbs. It is not certain whether a minimization of metabolic cost (Cmet) and an improvement in running performance is feasible with strength training of the postural and trunk muscles. Using kinematic, neuromuscular and metabolic measurements of running at two different speeds before and after a 12-week Pilates training programme, we tested the hypothesis that core training might improve the running Cmet and performance of trained runners. Thirty-two individuals were randomly assigned to the control group (CG, n = 16) or the Pilates group (PG, n = 16). Confirming our hypothesis, a significant improvement (p<0.05) was observed for running performance in the PG (pre: 25.65±0.4 min; post: 23.23±0.4 min) compared to the CG (pre: 25.33±0.58 min; post: 24.61±0.52 min). Similarly, the PG (4.33±0.07 J.kg-1.m-1) had better responses than the CG (4.71±0.11 J.kg-1.m-1) during post-training for Cmet. These findings were accompanied by decreased electromyographic activity of the postural muscles at submaximal running intensities in the PG. Overall, these results provide a rationale for selecting strength training strategies that target adaptations on specific postural and locomotor muscles for trained distance runners.

Differences between two subgroups of low back pain patients in lumbopelvic rotation and symmetry in the erector spinae and hamstring muscles during trunk flexion when standing.

PubMed

Kim, Min-hee; Yoo, Won-gyu; Choi, Bo-ram

2013-04-01

The present study was performed to examine lumbopelvic rotation and to identify asymmetry of the erector spinae and hamstring muscles in people with and without low back pain (LBP). The control group included 16 healthy subjects, the lumbar-flexion-rotation syndrome LBP group included 17 subjects, and the lumbar-extension-rotation syndrome LBP group included 14 subjects. Kinematic parameters were recorded using a 3D motion-capture system, and electromyography parameters were measured using a Noraxon TeleMyo 2400T. The two LBP subgroups showed significantly more lumbopelvic rotation during trunk flexion in standing than did the control group. The muscle activity and flexion-relaxation ratio asymmetries of the erector spinae muscles in the lumbar-flexion-rotation syndrome LBP group were significantly greater than those in the control group, and the muscle activity and flexion-relaxation ratio asymmetry of the hamstring muscles in the lumbar-extension-rotation syndrome LBP group were significantly greater than those in the control group. Imbalance or asymmetry of passive tissue could lead to asymmetry of muscular activation. Muscle imbalance can cause asymmetrical alignment or movements such as unexpected rotation. The results showed a greater increase in lumbopelvic rotation during trunk flexion in standing among the lumbar-flexion-rotation syndrome and lumbar-extension-rotation syndrome LBP groups compared with the control group. The differences between the two LBP subgroups may be a result of imbalance and asymmetry in erector spinae and hamstring muscle properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

Specific Stimuli Induce Specific Adaptations: Sensorimotor Training vs. Reactive Balance Training

PubMed Central

Freyler, Kathrin; Krause, Anne; Gollhofer, Albert; Ritzmann, Ramona

2016-01-01

Typically, balance training has been used as an intervention paradigm either as static or as reactive balance training. Possible differences in functional outcomes between the two modalities have not been profoundly studied. The objective of the study was to investigate the specificity of neuromuscular adaptations in response to two balance intervention modalities within test and intervention paradigms containing characteristics of both profiles: classical sensorimotor training (SMT) referring to a static ledger pivoting around the ankle joint vs. reactive balance training (RBT) using externally applied perturbations to deteriorate body equilibrium. Thirty-eight subjects were assigned to either SMT or RBT. Before and after four weeks of intervention training, postural sway and electromyographic activities of shank and thigh muscles were recorded and co-contraction indices (CCI) were calculated. We argue that specificity of training interventions could be transferred into corresponding test settings containing properties of SMT and RBT, respectively. The results revealed that i) postural sway was reduced in both intervention groups in all test paradigms; magnitude of changes and effect sizes differed dependent on the paradigm: when training and paradigm coincided most, effects were augmented (P<0.05). ii) These specificities were accompanied by segmental modulations in the amount of CCI, with a greater reduction within the CCI of thigh muscles after RBT compared to the shank muscles after SMT (P<0.05). The results clearly indicate the relationship between test and intervention specificity in balance performance. Hence, specific training modalities of postural control cause multi-segmental and context-specific adaptations, depending upon the characteristics of the trained postural strategy. In relation to fall prevention, perturbation training could serve as an extension to SMT to include the proximal segment, and thus the control of structures near to the body’s centre of mass, into training. PMID:27911944

The effects of Creatine Long-Term Supplementation on Muscle Morphology and Swimming Performance in Rats

PubMed Central

Yildiz, Ahmet; Ozdemir, Ercan; Gulturk, Sefa; Erdal, Sena

2009-01-01

Creatine (Cr) has been shown to increase the total muscle mass. The purpose of this study was to investigate the effect of Cr supplementation on muscle morphology and swimming performance, using an animal model. Each rat was subjected to exercise 15-minute period daily for the 12 weeks. The rats were randomly divided into four groups: no Cr supplementation (CON), no Cr supplementation and incomplete food intake (lacking lysine and methionine in diet for rats) (INCO), Cr supplementation 1 g·kg-1·day-1 (CREAT-I) and Cr supplementation 2 g·kg-1·day-1 (CREAT-II). Three months later, all groups adult rats exercised in swimming pool chambers. Swimming time was recorded as minute for each rat. Following swimming performance period, the animals were killed by cervical dislocation and the gastrocnemius and diaphragm muscles were dissected. Serial slices of 5-7 μm were allocated paraffin wax and histochemical staining procedure of cross-sections was carried out with heamatoxylin-eosin technics. All groups gained body weight at the end of 12 weeks but there was no statistical difference among them. Swimming time values were statistical difference between CREAT-II and CON group as well as between CREAT-I and CON group (p < 0.05). In the INCO group was determined increased connective tissue cell of the muscle sample. In contrast, in the CREAT-I and CREAT-II group, the basic histological changes were large-scale muscle fibers and hypertrophic muscle cells. These results suggest that long-term creatine supplementation increased the number of muscle fibers and enhanced endurance swimming performance in rats. Key points There is no study about the effects of creatine long-term supplementation on muscle morphology and swimming performance in rats. Long-term creatine supplementation increase muscle hypertrophy (but not body weight) and enhance endurance swimming performance in rats. The quantitative analysis indicated that the number of muscle fibers per defined area increased in creatine supplementation groups. PMID:24149591

Cycle ergometer and inspiratory muscle training offer modest benefit compared with cycle ergometer alone: a comprehensive assessment in stable COPD patients

PubMed Central

Luo, Yu-wen; Wang, Mei; Hu, Yu-he; Xu, Wen-hui; Zhou, Lu-qian; Chen, Rong-chang; Chen, Xin

2017-01-01

Background Cycle ergometer training (CET) has been shown to improve exercise performance of the quadriceps muscles in patients with COPD, and inspiratory muscle training (IMT) may improve the pressure-generating capacity of the inspiratory muscles. However, the effects of combined CET and IMT remain unclear and there is a lack of comprehensive assessment. Materials and methods Eighty-one patients with COPD were randomly allocated to three groups: 28 received 8 weeks of CET + IMT (combined training group), 27 received 8 weeks of CET alone (CET group), and 26 only received 8 weeks of free walking (control group). Comprehensive assessment including respiratory muscle strength, exercise capacity, pulmonary function, dyspnea, quality of life, emotional status, nutritional status, and body mass index, airflow obstruction, and exercise capacity index were measured before and after the pulmonary rehabilitation program. Results Respiratory muscle strength, exercise capacity, inspiratory capacity, dyspnea, quality of life, depression and anxiety, and nutritional status were all improved in the combined training and CET groups when compared with that in the control group (P<0.05) after pulmonary rehabilitation program. Inspiratory muscle strength increased significantly in the combined training group when compared with that in the CET group (ΔPImax [maximal inspiratory pressure] 5.20±0.89 cmH2O vs 1.32±0.91 cmH2O; P<0.05). However, there were no significant differences in the other indices between the two groups (P>0.05). Patients with weakened respiratory muscles in the combined training group derived no greater benefit than those without respiratory muscle weakness (P>0.05). There were no significant differences in these indices between the patients with malnutrition and normal nutrition after pulmonary rehabilitation program (P>0.05). Conclusion Combined training is more effective than CET alone for increasing inspiratory muscle strength. IMT may not be useful when combined with CET in patients with weakened inspiratory muscles. Nutritional status had slight impact on the effects of pulmonary rehabilitation. A comprehensive assessment approach can be more objective to evaluate the effects of combined CET and IMT. PMID:28919733

Cycle ergometer and inspiratory muscle training offer modest benefit compared with cycle ergometer alone: a comprehensive assessment in stable COPD patients.

PubMed

Wang, Kai; Zeng, Guang-Qiao; Li, Rui; Luo, Yu-Wen; Wang, Mei; Hu, Yu-He; Xu, Wen-Hui; Zhou, Lu-Qian; Chen, Rong-Chang; Chen, Xin

2017-01-01

Cycle ergometer training (CET) has been shown to improve exercise performance of the quadriceps muscles in patients with COPD, and inspiratory muscle training (IMT) may improve the pressure-generating capacity of the inspiratory muscles. However, the effects of combined CET and IMT remain unclear and there is a lack of comprehensive assessment. Eighty-one patients with COPD were randomly allocated to three groups: 28 received 8 weeks of CET + IMT (combined training group), 27 received 8 weeks of CET alone (CET group), and 26 only received 8 weeks of free walking (control group). Comprehensive assessment including respiratory muscle strength, exercise capacity, pulmonary function, dyspnea, quality of life, emotional status, nutritional status, and body mass index, airflow obstruction, and exercise capacity index were measured before and after the pulmonary rehabilitation program. Respiratory muscle strength, exercise capacity, inspiratory capacity, dyspnea, quality of life, depression and anxiety, and nutritional status were all improved in the combined training and CET groups when compared with that in the control group ( P <0.05) after pulmonary rehabilitation program. Inspiratory muscle strength increased significantly in the combined training group when compared with that in the CET group (ΔPI max [maximal inspiratory pressure] 5.20±0.89 cmH 2 O vs 1.32±0.91 cmH 2 O; P <0.05). However, there were no significant differences in the other indices between the two groups ( P >0.05). Patients with weakened respiratory muscles in the combined training group derived no greater benefit than those without respiratory muscle weakness ( P >0.05). There were no significant differences in these indices between the patients with malnutrition and normal nutrition after pulmonary rehabilitation program ( P >0.05). Combined training is more effective than CET alone for increasing inspiratory muscle strength. IMT may not be useful when combined with CET in patients with weakened inspiratory muscles. Nutritional status had slight impact on the effects of pulmonary rehabilitation. A comprehensive assessment approach can be more objective to evaluate the effects of combined CET and IMT.

Differential Effects of 7 and 16 Groups of Muscle Relaxation Training Following Repeated Submaximal Intensity Exercise in Young Football Players.

PubMed

Sharifah Maimunah, S M P; Hashim, H A

2016-02-01

This study compares two versions of progressive muscle relaxation (PMR) training (7 and 16 muscle groups) on oxygen consumption (VO2), heart rates, rating of perceived exertion and choice reaction time. Football (soccer) players (N = 26; M age = 13.4 yr., SD = 0.5) were randomly assigned to either 7 muscle groups PMR, 16 muscle groups PMR, or a control group. PMR training requires the participants to tense a muscle, hold the muscle contraction, and then relax it. Measurement was conducted prior to and after the completion of 12 sessions of PMR. The dependent variables were measured following four bouts of intermittent exercise consisting of 12 min. of running at 60% VO2max for 10 min. followed by running at 90% VO2max for 2 min. with a 3-min. rest for each bout. Lower VO2, heart rate, perceived exertion, and quicker reaction time were expected in both relaxation groups compared to the control group. The results revealed a significant reduction in heart rates and choice reaction time for both relaxation groups, but the longer version produced significantly quicker choice reaction time. © The Author(s) 2016.

Efficacy of progressive muscle relaxation training in reducing anxiety in patients with acute schizophrenia.

PubMed

Chen, Wen-Chun; Chu, Hsin; Lu, Ru-Band; Chou, Yuan-Hwa; Chen, Chung-Hua; Chang, Yue-Cune; O'Brien, Anthony Paul; Chou, Kuei-Ru

2009-08-01

The objective of this study was to examine the efficacy of progressive muscle relaxation training on anxiety in patients with acute schizophrenia. Many empirical studies have found progressive muscle relaxation training beneficial in reducing the psychological effects of anxiety. Progressive muscle relaxation training is also effective in reducing the distress symptoms associated with the symptomatology of schizophrenia. An experimental randomised controlled trial using repeated measures. The study was designed to examine the effects of progressive muscle relaxation training on patients diagnosed with schizophrenia. Study participants were acute psychiatric inpatients in Taiwan. Eighteen patients were block randomised and then assigned to an experimental or control group. The experimental group received progressive muscle relaxation training and the control group received a placebo intervention. Results from the Beck anxiety inventory were compared between groups as a pretest before intervention, on day 11 of intervention and one week post-test after the intervention was completed. Changes in finger temperature were measured throughout the experiment. The degree of anxiety improvement was significantly higher in the progressive muscle relaxation training group than in the control group after progressive muscle relaxation training intervention (p < 0.0001) and at follow-up (p = 0.0446; the mean BAI score fell from 16.4 pretest to -5.8 post-test. After adjusting for the change in patient finger temperature, the mean change in temperature was significantly different between the two patient groups. The average body temperature increased significantly after applying the progressive muscle relaxation training to patients with schizophrenia. This study demonstrated that progressive muscle relaxation training can effectively alleviate anxiety in patients with schizophrenia. Progressive muscle relaxation training is potentially an effective nursing intervention in the reduction of anxiety in patients diagnosed with schizophrenia, depending on the quality of their mental status at the time of intervention. Progressive muscle relaxation training is a useful intervention as it is proven to reduce anxiety levels across a spectrum of psychiatric disorders.

Hypertrophy Stimulation at the Onset of Type I Diabetes Maintains the Soleus but Not the EDL Muscle Mass in Wistar Rats

PubMed Central

Fortes, Marco A. S.; Scervino, Maria V. M.; Marzuca-Nassr, Gabriel N.; Vitzel, Kaio F.; da Justa Pinheiro, Carlos H.; Curi, Rui

2017-01-01

Diabetes mellitus induces a reduction in skeletal muscle mass and strength. Strength training is prescribed as part of treatment since it improves glycemic control and promotes increase of skeletal muscle mass. The mechanisms involved in overload-induced muscle hypertrophy elicited at the establishment of the type I diabetic state was investigated in Wistar rats. The purpose was to examine whether the overload-induced hypertrophy can counteract the hypotrophy associated to the diabetic state. The experiments were performed in oxidative (soleus) or glycolytic (EDL) muscles. PI3K/Akt/mTOR protein synthesis pathway was evaluated 7 days after overload-induced hypertrophy of soleus and of EDL muscles. The mRNA expression of genes associated with different signaling pathways that control muscle hypertrophy was also evaluated: mechanotransduction (FAK), Wnt/β-catenin, myostatin, and follistatin. The soleus and EDL muscles when submitted to overload had similar hypertrophic responses in control and diabetic animals. The increase of absolute and specific twitch and tetanic forces had the same magnitude as muscle hypertrophic response. Hypertrophy of the EDL muscle from diabetic animals mostly involved mechanical loading-stimulated PI3K/Akt/mTOR pathway besides the reduced activation of AMP-activated protein kinase (AMPK) and decrease of myostatin expression. Hypertrophy was more pronounced in the soleus muscle of diabetic animals due to a more potent activation of rpS6 and increased mRNA expression of insulin-like growth factor-1 (IGF-1), mechano-growth factor (MGF) and follistatin, and decrease of myostatin, MuRF-1 and atrogin-1 contents. The signaling changes enabled the soleus muscle mass and force of the diabetic rats to reach the values of the control group. PMID:29123487

Effects of the belt electrode skeletal muscle electrical stimulation system on lower extremity skeletal muscle activity: Evaluation using positron emission tomography.

PubMed

Numata, Hitoaki; Nakase, Junsuke; Inaki, Anri; Mochizuki, Takafumi; Oshima, Takeshi; Takata, Yasushi; Kinuya, Seigo; Tsuchiya, Hiroyuki

2016-01-01

Lower-extremity muscle weakness in athletes after lower limb trauma or surgery can hinder their return to sports, and the associated muscle atrophy may lead to deterioration in performance after returning to sports. Recently, belt electrode skeletal muscle electrical stimulation (B-SES) which can contract all the lower limb skeletal muscles simultaneously was developed. However, no study has evaluated skeletal muscle activity with B-SES. Since only superficial muscles as well as a limited number of muscles can be investigated using electromyography, we investigated whether positron emission tomography (PET) can evaluate the activity of all the skeletal muscles in the body simultaneously. The purpose of this study was to evaluate the effectiveness of the B-SES system using PET. Twelve healthy males (mean age, 24.3 years) were divided into two groups. The subjects in the control group remained in a sitting position for 10 min, and [(18)F] fluorodeoxyglucose (FDG) was intravenously injected. In the exercise group, subjects exercised using the B-SES system for 20 min daily for three consecutive days as a pre-test exercise. On the measurement day, they exercised for 10 min, received an injection of FDG, and exercised for another 10 min. PET-computed tomography images were obtained in each group 60 min after the FDG injection. Regions of interest were drawn in each lower-extremity muscle. We compared each skeletal muscle metabolism using the standardized uptake value. In the exercise group, FDG accumulation in the gluteus maximus, gluteus medius, gluteus minimus, quadriceps femoris, sartorius, and hamstrings was significantly higher than the muscles in the control (P < 0.05). Exercise with B-SES increased the skeletal muscle activity of the gluteal muscles as well as the most lower-extremity muscles simultaneously. Copyright © 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Functional recovery of completely denervated muscle: implications for innervation of tissue-engineered muscle.

PubMed

Kang, Sung-Bum; Olson, Jennifer L; Atala, Anthony; Yoo, James J

2012-09-01

Tissue-engineered muscle has been proposed as a solution to repair volumetric muscle defects and to restore muscle function. To achieve functional recovery, engineered muscle tissue requires integration of the host nerve. In this study, we investigated whether denervated muscle, which is analogous to tissue-engineered muscle tissue, can be reinnervated and can recover muscle function using an in vivo model of denervation followed by neurotization. The outcomes of this investigation may provide insights on the ability of tissue-engineered muscle to integrate with the host nerve and acquire normal muscle function. Eighty Lewis rats were classified into three groups: a normal control group (n=16); a denervated group in which sciatic innervations to the gastrocnemius muscle were disrupted (n=32); and a transplantation group in which the denervated gastrocnemius was repaired with a common peroneal nerve graft into the muscle (n=32). Neurofunctional behavior, including extensor postural thrust (EPT), withdrawal reflex latency (WRL), and compound muscle action potential (CMAP), as well as histological evaluations using alpha-bungarotoxin and anti-NF-200 were performed at 2, 4, 8, and 12 weeks (n=8) after surgery. We found that EPT was improved by transplantation of the nerve grafts, but the EPT values in the transplanted animals at 12 weeks postsurgery were still significantly lower than those measured for the normal control group at 4 weeks (EPT, 155.0±38.9 vs. 26.3±13.8 g, p<0.001; WRL, 2.7±2.30 vs. 8.3±5.5 s, p=0.027). In addition, CMAP latency and amplitude significantly improved with time after surgery in the transplantation group (p<0.001, one-way analysis of variance), and at 12 weeks postsurgery, CMAP latency and amplitude were not statistically different from normal control values (latency, 0.9±0.0 vs. 1.3±0.7 ms, p=0.164; amplitude, 30.2±7.0 vs. 46.4±26.9 mV, p=0.184). Histologically, regeneration of neuromuscular junctions was seen in the transplantation group. This study indicates that transplanted nerve tissue is able to regenerate neuromuscular junctions within denervated muscle, and thus the muscle can recover partial function. However, the function of the denervated muscle remains in the subnormal range even at 12 weeks after direct nerve transplantation. These results suggest that tissue-engineered muscle, which is similarly denervated, could be innervated and become functional in vivo if it is properly integrated with the host nerve.

Muscle Degeneration Associated With Rotator Cuff Tendon Release and/or Denervation in Sheep.

PubMed

Gerber, Christian; Meyer, Dominik C; Flück, Martin; Valdivieso, Paola; von Rechenberg, Brigitte; Benn, Mario C; Wieser, Karl

2017-03-01

The effect of an additional neurological injury (suprascapular nerve traction injury) to a chronically retracted rotator cuff muscle is incompletely understood and warrants clarification. To investigate the microscopic and macroscopic muscle degeneration patterns caused by tendon release and/or muscle denervation in a sheep rotator cuff model. Controlled laboratory study. Infraspinatus muscle biopsy specimens (for histological analysis) were obtained from 18 Swiss alpine sheep before and 16 weeks after release of the infraspinatus tendon (tenotomy [T] group; n = 6), transection of the suprascapular nerve (neurectomy [N] group; n = 6), or tendon release plus nerve transection (tenotomy + neurectomy [T&N] group; n = 6). Magnetic resonance imaging (MRI) and computed tomography (CT) were used to assess retraction (CT), muscle density (CT), volume (MRI T2), and fat fraction (MRI Dixon). Stiffness of the infraspinatus was measured with a spring scale. At 16 weeks postoperatively, the mean infraspinatus muscle volume had decreased significantly more after neurectomy (to 47% ± 7% of the original volume; P = .001) and tenotomy plus neurectomy (48% ± 13%; P = .005) than after tenotomy alone (78% ± 11%). Conversely, the mean amount of intramuscular fat (CT/MRI Dixon) was not significantly different in the 3 groups (T group: 50% ± 9%; N group: 40% ± 11%; T&N group: 46% ± 10%) after 16 weeks. The mean myotendinous retraction (CT) was not significantly different in the T and T&N groups (5.8 ± 1.0 cm and 6.4 ± 0.4 cm, respectively; P = .26). Stiffness was, however, most increased after additional neurectomy. In contrast to muscle changes after tendon release, denervation of the muscle led to a decrease in the pennation angle of lengthened muscle fibers, with a reduced mean cross-sectional area of pooled muscle fibers, a slow- to fast-type transformation, and an increase in the area percentage of hybrid fibers, leading to overall significantly greater atrophy of the corresponding muscle. Although it is unclear which experimental group (T or T&N) most accurately reflects the clinical scenario in a given case, these findings provide baseline information for clinical differentiation between muscle changes caused by denervation or rotator cuff tendon lesions. The findings of this study help to understand how and to which extent a neurological lesion of the supplying suprascapular nerve could influence the pattern of anatomic-physiological muscular changes after rotator cuff tendon tears.

Repeated blood flow restriction induces muscle fiber hypertrophy.

PubMed

Sudo, Mizuki; Ando, Soichi; Kano, Yutaka

2017-02-01

We recently developed an animal model to investigate the effects of eccentric contraction (ECC) and blood flow restriction (BFR) on muscle tissue at the cellular level. This study clarified the effects of repeated BFR, ECC, and BFR combined with ECC (BFR+ECC) on muscle fiber hypertrophy. Male Wistar rats were assigned to 3 groups: BFR, ECC, and BFR+ECC. The contralateral leg in the BFR group served as a control (CONT). Muscle fiber cross-sectional area (CSA) of the tibialis anterior was determined after the respective treatments for 6 weeks. CSA was greater in the BFR+ECC group than in the CONT (P < 0.01) and ECC (P < 0.05) groups. CSA was greater in the BFR group than that in the CONT group (P < 0.05). These results suggest that repeated BFR alone as well as BFR+ECC induces muscle fiber hypertrophy at the cellular level. Muscle Nerve 55: 274-276, 2017. © 2016 Wiley Periodicals, Inc.

Unilateral microform cleft lip repair: application of muscle tension line group theory.

PubMed

Yin, Ningbei; Song, Tao; Wu, Jiajun; Chen, Bo; Ma, Hengyuan; Zhao, Zhenmin; Wang, Yongqian; Li, Haidong; Wu, Di

2015-03-01

In microform cleft lip repair, reconstructing the elaborate structures is difficult. We describe a new technique of unilateral microform cleft lip repair that is based on the muscle tension line group theory. According to the shape of Cupid bow, a different small incision is used without creating an obvious cutaneous scar. First, the nasolabial muscle around the nasal floor (the first auxiliary tension line group) is reconstructed, and then the orbicularis oris muscle around the philtrum (the second auxiliary tension line group) is reconstructed based on the muscle tension line group theory. From June 2006 to June 2012, the technique was used in 263 unilateral microform cleft lip repairs. For 18 months, 212 patients were followed up. The appearance of the nasal alar, nasal sill, philtrum, and Cupid bow peak improved. Most patients had a satisfactory appearance. Based on the muscle tension line group theory, using this technique offers the ability to adduct the nasal alar effectively to form a good nasal sill and philtrum.

Myorelaxant Effect of Bee Venom Topical Skin Application in Patients with RDC/TMD Ia and RDC/TMD Ib: A Randomized, Double Blinded Study

PubMed Central

Baron, Stefan

2014-01-01

The aim of the study was the evaluation of myorelaxant action of bee venom (BV) ointment compared to placebo. Parallel group, randomized double blinded trial was performed. Experimental group patients were applying BV for 14 days, locally over masseter muscles, during 3-minute massage. Placebo group patients used vaseline for massage. Muscle tension was measured twice (TON1 and TON2) in rest muscle tonus (RMT) and maximal muscle contraction (MMC) on both sides, right and left, with Easy Train Myo EMG (Schwa-medico, Version 3.1). Reduction of muscle tonus was statistically relevant in BV group and irrelevant in placebo group. VAS scale reduction was statistically relevant in both groups: BV and placebo. Physiotherapy is an effective method for myofascial pain treatment, but 0,0005% BV ointment gets better relief in muscle tension reduction and analgesic effect. This trial is registered with Clinicaltrials.gov NCT02101632. PMID:25050337

Descending pathways to the cutaneus trunci muscle motoneuronal cell group in the cat

NASA Technical Reports Server (NTRS)

Holstege, Gert; Blok, Bertil F.

1989-01-01

Pathways involved in the cutaneous trunci muscle (CTM) reflex in the cat were investigated. Experimental animals were injected with tritium-labeled L-leucine into their spinal cord, brain stem, or diencephalon and, after six weeks, perfused with 10-percent formalin. The brains and spinal cords were postfixed in formalin and were cut into transverse 25-micron-thick frozen sections for autoradiography. Results based on injections in the C1, C2, C6, and C8 segments suggest that propriospinal pathways to the CTM motor nucleus originating in the cervical cord do no exist, although these propriospinal projections are very strong to all other motoneuronal cell groups surrounding the CTM motor nucleus. The results also demonstrate presence of specific supraspinal projections to the CTM motor nucleus, originating in the contralateral nucleus retroambiguous and the ipsilateral dorsolateral pontine tegmentum.

Skeletal muscle weakness in osteogenesis imperfecta mice.

PubMed

Gentry, Bettina A; Ferreira, J Andries; McCambridge, Amanda J; Brown, Marybeth; Phillips, Charlotte L

2010-09-01

Exercise intolerance, muscle fatigue and weakness are often-reported, little-investigated concerns of patients with osteogenesis imperfecta (OI). OI is a heritable connective tissue disorder hallmarked by bone fragility resulting primarily from dominant mutations in the proα1(I) or proα2(I) collagen genes and the recently discovered recessive mutations in post-translational modifying proteins of type I collagen. In this study we examined the soleus (S), plantaris (P), gastrocnemius (G), tibialis anterior (TA) and quadriceps (Q) muscles of mice expressing mild (+/oim) and moderately severe (oim/oim) OI for evidence of inherent muscle pathology. In particular, muscle weight, fiber cross-sectional area (CSA), fiber type, fiber histomorphology, fibrillar collagen content, absolute, relative and specific peak tetanic force (P(o), P(o)/mg and P(o)/CSA respectively) of individual muscles were evaluated. Oim/oim mouse muscles were generally smaller, contained less fibrillar collagen, had decreased P(o) and an inability to sustain P(o) for the 300-ms testing duration for specific muscles; +/oim mice had a similar but milder skeletal muscle phenotype. +/oim mice had mild weakness of specific muscles but were less affected than their oim/oim counterparts which demonstrated readily apparent skeletal muscle pathology. Therefore muscle weakness in oim mice reflects inherent skeletal muscle pathology. Copyright © 2010 Elsevier B.V. All rights reserved.

Lumbar muscle structure and function in chronic versus recurrent low back pain: a cross-sectional study.

PubMed

Goubert, Dorien; De Pauw, Robby; Meeus, Mira; Willems, Tine; Cagnie, Barbara; Schouppe, Stijn; Van Oosterwijck, Jessica; Dhondt, Evy; Danneels, Lieven

2017-09-01

Heterogeneity exists within the low back pain (LBP) population. Some patients recover after every pain episode, whereas others suffer daily from LBP complaints. Until now, studies rarely make a distinction between recurrent low back pain (RLBP) and chronic low back pain (CLBP), although both are characterized by a different clinical picture. Clinical experiences also indicate that heterogeneity exists within the CLBP population. Muscle degeneration, like atrophy, fat infiltration, alterations in muscle fiber type, and altered muscle activity, compromises proper biomechanics and motion of the spinal units in LBP patients. The amount of alterations in muscle structure and muscle function of the paraspinal muscles might be related to the recurrence or chronicity of LBP. The aim of this experimental study is to evaluate differences in muscle structure (cross-sectional area and lean muscle fat index) and muscle activity of the multifidus (MF) and erector spinae (ES) during trunk extension, in patients with RLBP, non-continuous CLBP, and continuous CLBP. This cross-sectional study took place in the university hospital of Ghent, Belgium. Muscle structure characteristics and muscle activity were assessed by magnetic resonance imaging (MRI). Fifty-five adults with non-specific LBP (24 RLBP in remission, 15 non-continuous CLBP, 16 continuous CLBP) participated in this study. Total cross-sectional area, muscle cross-sectional area, fat cross-sectional area, lean muscle fat index, T2-rest and T2-shift were assessed. A T1-weighted Dixon MRI scan was used to evaluate spinal muscle cross-sectional area and fat infiltration in the lumbar MF and ES. Muscle functional MRI was used to evaluate the muscle activity of the lumbar MF and ES during a lumbar extension exercise. Before and after the exercise, a pain assessment was performed. This study was supported by grants from the Special Research Fund of Ghent University (DEF12/AOP/022) without potential conflict of interest-associated biases in the text of the paper. Fat cross-sectional area and lean muscle fat index were significantly higher in MF and ES in continuous CLBP compared with non-continuous CLBP and RLBP (p<.05). No differencesbetween groups were found for total cross-sectional area and muscle cross-sectional area in MF or ES (p>.05). Also, no significant differences between groups for T2-rest were established. T2-shift, however, was significantly lower in MF and ES in RLBP compared with, respectively, non-continuous CLBP and continuous CLBP (p<.05). These results indicate a higher amount of fat infiltration in the lumbar muscles, in the absence of clear atrophy, in continuous CLBP compared with RLBP. A lower metabolic activity of the lumbar muscles was seen in RLBP replicating a relative lower intensity in contractions performed by the lumbar muscles in RLBP compared with non-continuous and continuous CLBP. In conclusion, RLBP differs from continuous CLBP for both muscle structure and muscle function, whereas non-continuous CLBP seems comparable with RLBP for lumbar muscle structure and with continuous CLBP for lumbar muscle function. These results underline the differences in muscle structure and muscle function between different LBP populations. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of vibration on muscle strength imbalance in lower extremity using multi-control whole body vibration platform.

PubMed

Yu, Chang Ho; Seo, Shin Bae; Kang, Seung Rok; Kim, Kyung; Kwon, Tae Kyu

2015-01-01

This study shows the improvement of muscle activity and muscle strength imbalance in the lower extremities through independent exercise loads in vibration platform. Twenty females of age 20 participated in this study. The subjects were divided into WBV group, with more than 10% of muscle strength imbalance between left and right the lower extremities, and control group, with less than 10% of muscle strength imbalance between left and right the lower extremities. As the prior experiment showed, different exercise postures provide different muscular activities. As a result, the highest muscular activity was found to be in the low squat posture. Therefore, the LS posture was selected for the exercise in this experiment. Vibration intensities were applied to dominant muscle and non-dominant muscle, and the vibration frequency was fixed at 25Hz for the WBV group. The control group was asked to perform the same exercise as the WBV group, without stimulated vibration. This exercise was conducted for a total of 4 weeks. As a result, the WBV group which showed an average deviation of 16% before the experiment, tended to decrease approximately to 5%. In this study, vibration exercise using load deviation is shown to be effective in improving the muscle strength imbalance.

Stomatognathic function in Duchenne muscular dystrophy: a case-control study.

PubMed

Ferreira, Bruno; Da Silva, Gabriel Pádua; Gonçalves, Camila Rosa; Arnoni, Veridiana Wanshi; Siéssere, Selma; Semprini, Marisa; Verri, Edson Donizetti; Chaves, Thais Cristina; Regalo, Simone Cecilio Hallak

2016-05-01

This study aimed to analyse electromyographic activity, masticatory efficiency, muscle thickness, and bite force of individuals with Duchenne muscular dystrophy (DMD). Forty males aged 4-15 years, 20 with DMD and 20 healthy age-, height-, and weight-matched controls, underwent electromyography and ultrasonography of temporalis, masseter, and sternocleidomastoid muscles during postural control of the jaw, mastication, and maximal molar bite force. The normalized electromyography signals showed higher activity in masseter and temporal muscles at rest, during protrusion, left and right laterality, and fatigue condition in the group with DMD than in the comparison group (p≤0.05). For masticatory efficiency of cycles, in analysis of non-habitual chewing of flavourless gum, and habitual chewing of peanuts and raisins, the group with DMD presented lower averages (p≤0.05). For the muscle thickness, the results showed that there was a lower muscle thickness in the group with DMD for all muscles during the rest and maximal voluntary contraction, except for masseter and sternocleidomastoid in the maximal voluntary contraction. In the maximal molar bite force, the group with DMD presented higher values for both sides than the comparison group (p≤0.05). Patients with DMD show muscle changes related to the stomatognathic system, in their activity, bite force, and muscle thickness. © 2016 Mac Keith Press.

Differences in muscle sympathetic nerve response to isometric exercise in different muscle groups.

PubMed

Saito, M

1995-01-01

The aim of this study was to examine the effects of muscle fibre composition on muscle sympathetic nerve activity (MSNA) in response to isometric exercise. The MSNA, recorded from the tibial nerve by a microneurographic technique during contraction and following arterial occlusion, was compared in three different muscle groups: the forearm (handgrip), anterior tibialis (foot dorsal contraction), and soleus muscles (foot plantar contraction) contracted separately at intensities of 20%, 33% and 50% of the maximal voluntary force. The increases in MSNA relative to control levels during contraction and occlusion were significant at all contracting forces for handgrip and at 33% and 50% of maximal for dorsal contraction, but there were no significant changes, except during exercise at 50%, for plantar contraction. The size of the MSNA response correlated with the contraction force in all muscle groups. Pooling data for all contraction forces, there were different MSNA responses among muscle groups in contraction forces (P = 0.0001, two-way analysis of variance), and occlusion periods (P = 0.0001). The MSNA increases were in the following order of magnitude: handgrip, dorsal, and plantar contractions. The order of the fibre type composition in these three muscles is from equal numbers of types I and II fibres in the forearm to increasing number of type I fibres in the leg muscles. The different MSNA responses to the contraction of different muscle groups observed may have been due in part to muscle metaboreflex intensity influenced by their metabolic capacity which is related to by their metabolic capacity which is related to the fibre type.

Clinically-evident tophi are associated with reduced muscle force in the foot and ankle in people with gout: a cross-sectional study.

PubMed

Stewart, Sarah; Dalbeth, Nicola; Otter, Simon; Gow, Peter; Kumar, Sunil; Rome, Keith

2017-01-01

The foot and ankle represent a common site for tophi in people with gout, yet it is unclear whether the presence of tophi is related to impaired muscle function. This study aimed to determine the association between foot and ankle tophi and muscle force in people with gout. Participants with gout were stratified into two groups based on the presence of clinically-evident tophi affecting the foot or ankle on physical examination. Isometric muscle force for plantarflexion, dorsiflexion, inversion and eversion was measured using static dynamometry. Mixed-models regression was used to determine the difference in muscle force between the two groups while adjusting for age, disease duration and foot pain. This model was also used to determine the difference in muscle force between presence and absence of tophi at specific locations within the foot and ankle. In addition, Pearson's correlations were used to determine the association between total foot tophus count and muscle force. Fifty-seven participants were included (22 with foot or ankle tophi and 35 without foot or ankle tophi). Foot and ankle tophi were most often seen at the Achilles tendon. After adjusting for age, disease duration and foot pain, participants with tophi had significantly reduced muscle force during plantarflexion ( P  < 0.001), dorsiflexion ( P  = 0.003), inversion ( P  = 0.003) and eversion ( P  = 0.001) when compared to participants without tophi. Those with Achilles tophi had significantly reduced force during plantarflexion ( P  < 0.001), inversion ( P  = 0.008) and eversion ( P  = 0.001). No significant differences in muscle force were observed between the presence and absence of tophi at other foot or ankle locations. There were also no significant correlations between total foot tophus count and muscle force (all P  > 0.05). In people with gout, clinically-evident foot or ankle tophi are associated with muscle force deficits during foot plantarflexion, dorsiflexion, inversion and eversion, which persist despite adjusting for age, disease duration and foot pain. Tophi at the Achilles tendon, which associate with force deficits, may contribute to reduced muscular activation and consequent disuse muscle atrophy.

Exercise training prevents skeletal muscle damage in an experimental sepsis model

PubMed Central

Coelho, Carla Werlang; Jannig, Paulo R; de Souza, Arlete B; Fronza, Hercilio; Westphal, Glauco A; Petronilho, Fabricia; Constantino, Larissa; Dal-Pizzol, Felipe; Ferreira, Gabriela K; Streck, Emilio E; Silva, Eliezer

2013-01-01

OBJECTIVE: Oxidative stress plays an important role in skeletal muscle damage in sepsis. Aerobic exercise can decrease oxidative stress and enhance antioxidant defenses. Therefore, it was hypothesized that aerobic exercise training before a sepsis stimulus could attenuate skeletal muscle damage by modulating oxidative stress. Thus, the aim of this study was to evaluate the effects of aerobic physical preconditioning on the different mechanisms that are involved in sepsis-induced myopathy. METHODS: Male Wistar rats were randomly assigned to either the untrained or trained group. The exercise training protocol consisted of an eight-week treadmill program. After the training protocol, the animals from both groups were randomly assigned to either a sham group or a cecal ligation and perforation surgery group. Thus, the groups were as follows: sham, cecal ligation and perforation, sham trained, and cecal ligation and perforation trained. Five days after surgery, the animals were euthanized and their soleus and plantaris muscles were harvested. Fiber cross-sectional area, creatine kinase, thiobarbituric acid reactive species, carbonyl, catalase and superoxide dismutase activities were measured. RESULTS: The fiber cross-sectional area was smaller, and the creatine kinase, thiobarbituric acid reactive species and carbonyl levels were higher in both muscles in the cecal ligation and perforation group than in the sham and cecal ligation and perforation trained groups. The muscle superoxide dismutase activity was higher in the cecal ligation and perforation trained group than in the sham and cecal ligation and perforation groups. The muscle catalase activity was lower in the cecal ligation and perforation group than in the sham group. CONCLUSION: In summary, aerobic physical preconditioning prevents atrophy, lipid peroxidation and protein oxidation and improves superoxide dismutase activity in the skeletal muscles of septic rats. PMID:23420166

One session of partial-body cryotherapy (-110 °C) improves muscle damage recovery.

PubMed

Ferreira-Junior, J B; Bottaro, M; Vieira, A; Siqueira, A F; Vieira, C A; Durigan, J L Q; Cadore, E L; Coelho, L G M; Simões, H G; Bemben, M G

2015-10-01

To evaluate the effects of a single session of partial-body cryotherapy (PBC) on muscle recovery, 26 young men performed a muscle-damaging protocol that consisted of five sets of 20 drop jumps with 2-min rest intervals between sets. After the exercise, the PBC group (n = 13) was exposed to 3 min of PBC at -110 °C, and the control group (n = 13) was exposed to 3 min at 21 °C. Anterior thigh muscle thickness, isometric peak torque, and muscle soreness of knee extensors were measured pre, post, 24, 48, 72, and 96 h following exercise. Peak torque did not return to baseline in control group (P < 0.05), whereas the PBC group recovered peak torques 96 h post exercise (P > 0.05). Peak torque was also higher after PBC at 72 and 96 h compared with control group (P < 0.05). Muscle thickness increased after 24 h in the control group (P < 0.05) and was significantly higher compared with the PBC group at 24 and 96 h (P < 0.05). Muscle soreness returned to baseline for the PBC group at 72 h compared with 96 h for controls. These results indicate that PBC after strenuous exercise may enhance recovery from muscle damage. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The influence of wheelchair propulsion technique on upper extremity muscle demand: a simulation study.

PubMed

Rankin, Jeffery W; Kwarciak, Andrew M; Richter, W Mark; Neptune, Richard R

2012-11-01

The majority of manual wheelchair users will experience upper extremity injuries or pain, in part due to the high force requirements, repetitive motion and extreme joint postures associated with wheelchair propulsion. Recent studies have identified cadence, contact angle and peak force as important factors for reducing upper extremity demand during propulsion. However, studies often make comparisons between populations (e.g., able-bodied vs. paraplegic) or do not investigate specific measures of upper extremity demand. The purpose of this study was to use a musculoskeletal model and forward dynamics simulations of wheelchair propulsion to investigate how altering cadence, peak force and contact angle influence individual muscle demand. Forward dynamics simulations of wheelchair propulsion were generated to emulate group-averaged experimental data during four conditions: 1) self-selected propulsion technique, and while 2) minimizing cadence, 3) maximizing contact angle, and 4) minimizing peak force using biofeedback. Simulations were used to determine individual muscle mechanical power and stress as measures of muscle demand. Minimizing peak force and cadence had the lowest muscle power requirements. However, minimizing peak force increased cadence and recovery power, while minimizing cadence increased average muscle stress. Maximizing contact angle increased muscle stress and had the highest muscle power requirements. Minimizing cadence appears to have the most potential for reducing muscle demand and fatigue, which could decrease upper extremity injuries and pain. However, altering any of these variables to extreme values appears to be less effective; instead small to moderate changes may better reduce overall muscle demand. Copyright © 2012 Elsevier Ltd. All rights reserved.

Relative Activity of Abdominal Muscles during Commonly Prescribed Strengthening Exercises.

ERIC Educational Resources Information Center

Willett, Gilbert M.; Hyde, Jennifer E.; Uhrlaub, Michael B.; Wendel, Cara L.; Karst, Gregory M.

2001-01-01

Examined the relative electromyographic (EMG) activity of upper and lower rectus abdominis (LRA) and external oblique (EOA) muscles during five abdominal strengthening exercises. Isometric and dynamic EMG data indicated that abdominal strengthening exercises activated various abdominal muscle groups. For the LRA and EOA muscle groups, there were…

"Functional" Inspiratory and Core Muscle Training Enhances Running Performance and Economy.

PubMed

Tong, Tomas K; McConnell, Alison K; Lin, Hua; Nie, Jinlei; Zhang, Haifeng; Wang, Jiayuan

2016-10-01

Tong, TK, McConnell, AK, Lin, H, Nie, J, Zhang, H, and Wang, J. "Functional" inspiratory and core muscle training enhances running performance and economy. J Strength Cond Res 30(10): 2942-2951, 2016-We compared the effects of two 6-week high-intensity interval training interventions. Under the control condition (CON), only interval training was undertaken, whereas under the intervention condition (ICT), interval training sessions were followed immediately by core training, which was combined with simultaneous inspiratory muscle training (IMT)-"functional" IMT. Sixteen recreational runners were allocated to either ICT or CON groups. Before the intervention phase, both groups undertook a 4-week program of "foundation" IMT to control for the known ergogenic effect of IMT (30 inspiratory efforts at 50% maximal static inspiratory pressure [P0] per set, 2 sets per day, 6 days per week). The subsequent 6-week interval running training phase consisted of 3-4 sessions per week. In addition, the ICT group undertook 4 inspiratory-loaded core exercises (10 repetitions per set, 2 sets per day, inspiratory load set at 50% post-IMT P0) immediately after each interval training session. The CON group received neither core training nor functional IMT. After the intervention phase, global inspiratory and core muscle functions increased in both groups (p ≤ 0.05), as evidenced by P0 and a sport-specific endurance plank test (SEPT) performance, respectively. Compared with CON, the ICT group showed larger improvements in SEPT, running economy at the speed of the onset of blood lactate accumulation, and 1-hour running performance (3.04% vs. 1.57%, p ≤ 0.05). The changes in these variables were interindividually correlated (r ≥ 0.57, n = 16, p ≤ 0.05). Such findings suggest that the addition of inspiratory-loaded core conditioning into a high-intensity interval training program augments the influence of the interval program on endurance running performance and that this may be underpinned by an improvement in running economy.

Stocking density affects the growth performance and metabolism of Amur sturgeon by regulating expression of genes in the GH/IGF axis

NASA Astrophysics Data System (ADS)

Ren, Yuanyuan; Wen, Haishen; Li, Yun; Li, Jifang

2017-07-01

The effects of stocking density on the growth and metabolism of Amur sturgeon were assessed. Amur sturgeon were grown for 70 days at three different stocking densities (low stocking density, LSD: 5.5 kg/m3; medium stocking density, MSD: 8.0 kg/m3; and high stocking density, HSD: 11.0 kg/m3), and the biometric index, muscle composition, and serum biochemical parameters were evaluated. In addition, pituitary, liver, and muscle samples were collected for gene cloning and expression analyses. After 70 days of growth, the fish maintained at HSD had significantly lower final body weight and specific growth rate, and a higher feed conversion ratio than those of the fish in the MSD and LSD groups. The HSD group had the lowest lipid and protein concentrations in serum and muscle. The serum cortisol concentration increased significantly in the HSD group, indicating that the stress-response system was activated in these fish. There was no change in the concentration of serum insulin-like growth factor 2 (IGF-2), while the concentrations of serum growth hormone (GH) and insulin-like growth factor 1 (IGF-1) decreased in the HSD group. The full-length cDNAs of GH and IGF-2 genes (995-bp and 1 207-bp long, respectively), were cloned and analyzed. In the HSD group, the expressions of GH in the pituitary and growth hormone receptor (GHR) and IGF-1 in the liver were down-regulated at the end of the 70-day experiment. In the HSD group, the transcript level of IGF-2 significantly decreased in the liver, but did not change in muscle. Overall, our results indicated that a HSD negatively affects the growth performance and leads to changes in lipid and protein metabolism in Amur sturgeon. The down-regulated expression of genes related to the GH/IGF axis may be responsible for the poor growth performance of Amur sturgeon under crowding stress.

Calcineurin-NFAT Signaling and Neurotrophins Control Transformation of Myosin Heavy Chain Isoforms in Rat Soleus Muscle in Response to Aerobic Treadmill Training.

PubMed

Liu, Wenfeng; Chen, Gan; Li, Fanling; Tang, Changfa; Yin, Dazhong

2014-12-01

This study elucidated the role of CaN-NFAT signaling and neurotrophins on the transformation of myosin heavy chain isoforms in the rat soleus muscle fiber following aerobic exercise training. To do so, we examined the content and distribution of myosin heavy chain (MyHC) isoforms in the rat soleus muscle fiber, the activity of CaN and expression of NFATc1 in these fibers, and changes in the expression of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neutrophin-3 (NT-3) in the soleus and striatum following high-and medium-intensity aerobic treadmill training. Specific pathogen-free 2 month old male Sprague-Dawley (SD) rats were randomly divided into three groups: Control group (Con, n = 8), moderate-intensity aerobic exercise group (M-Ex, n = 8) and high-intensity aerobic exercise group (H-Ex, n = 8). We used ATPase staining to identify the muscle fiber type I and II, SDS-PAGE to separate and analyze the isoforms MyHCI, MyHCIIA, MyHCIIB and MyHCIIx, and performed western blots to determine the expression of NFATc1, NGF, BDNF and NT-3. CaN activity was measured using a colorimetric assay. In the soleus muscle, 8 weeks of moderate-intensity exercise can induce transformation of MyHC IIA and MyHC IIB to MyHC IIX and MyHC I (p < 0.01), while high-intensity treadmill exercise can induce transform MyHC IIx to MyHC IIB, MyHC IIA and MyHC I (p < 0.01). In comparison to the control group, CaN activity and NFATcl protein level were significantly increased in both the M-Ex and H-Ex groups (p < 0.05, p < 0.01), with a more pronounced upregulation in the M-Ex group (p < 0.05). Eight weeks of moderate- and high-intensity aerobic exercise induced the expression of NGF, BDNF and NT-3 in the soleus muscle and the striatum (p < 0.01), with the most significant increase in the H-Ex group (p < 0.01). In the rat soleus muscle, (1) CaN-NFATcl signaling contributes to the conversion of MyHC I isoform in response to moderate-intensity exercise; (2) Neurotrophins NGF, BDNF and NT-3 might play a role in the conversion of MyHC II isoform in response to high-intensity treadmill exercise. Key pointsEight weeks of moderate-intensity treadmill training induces the transformation MyHC IIA and MyHC IIB to MyHC IIX and MyHC I in the soleus muscles, while high-intensity exercise leads to transformation of MyHC IIX to MyHC IIA, MyHC IIB and MyHC I.MyHC I conversion in response to moderate-intensity aerobic exercise is mediated by calcineurin-NFATcl signaling.Eight weeks of moderate- and high-ntensity aerobic exercise induces the expression of NGF, BDNF and NT-3 in expression noted in rats subjected to high-intensity training. NGF and NT-3 expression in the striatum is lower than in the soleus muscle, while BDNF levels are similar. Neurotrophins may be involved in mediating MyHC II conversion in response to high-intensity aerobic exercise.

Maturity- and sex-related changes in tibial bone geometry, strength and bone-muscle strength indices during growth: a 20-month pQCT study.

PubMed

Macdonald, Heather M; Kontulainen, Saija A; Mackelvie-O'Brien, Kerry J; Petit, Moira A; Janssen, Patricia; Khan, Karim M; McKay, Heather A

2005-06-01

During growth, bone strength is conferred through subtle adaptations in bone mass and geometry in response to muscle forces. Few studies have examined the changes in bone geometry, strength and the bone-muscle strength relationship across maturity in boys and girls. Our aims were to describe (i) 20-month changes in bone geometry and strength at the tibial midshaft across three maturity groups of boys and girls, (ii) differences in these adaptations between sexes at the same approximate level of maturity and (iii) the bone-muscle strength relationship across maturity groups of boys and girls and between sexes. We used peripheral quantitative computed tomography (pQCT, Stratec XCT-2000) to measure change in total bone cross-sectional area (ToA, mm(2)), cortical area (CoA, mm(2)), average cortical thickness (C.Th., mm), section modulus (mm(3)) and muscle cross-sectional area (mm(2)) at the tibial midshaft (50% site) in 128 EARLY-, PERI- and POST-pubertal girls (n = 69, 11.9 +/- 0.6 years) and boys (n = 59, 12.0 +/- 0.6 years) across 20 months. We also calculated two bone-muscle strength indices (BMSI) for compression (CoA/MCSA) and bending [strength index/MCSA; where strength index = Z / (tibial length / 2)]. EARLY boys and girls had smaller ToA at baseline than same sex PERI or POST participants. There were no sex differences in ToA or CoA at baseline; however, boys increased both parameters significantly more than girls in every maturity group (8.5-11.1%, P < 0.01). These changes in bone geometry conferred greater gains in bone strength for boys compared with girls in each maturity group (13.8-15.6%, P < 0.01). Baseline BMSIs did not differ between sexes for EARLY and PERI groups, whereas BMSIs were significantly higher for POST boys compared with POST girls (P < 0.05). BMSIs decreased for EARLY and PERI girls (-7.4-(-1.1%)) whereas the ratios remained stable for EARLY and PERI boys (-0.6-2.5%). This sex difference in BMSI change was due to a relatively greater increase in CoA among EARLY and PERI boys compared with same-maturity girls. BMSIs remained stable in POST girls and decreased in POST boys due to relatively greater gains in MCSA. This study provides novel longitudinal descriptions of the maturity- and sex-specific changes in bone geometry, strength and bone-muscle strength indices.

Myositis-specific autoantibodies are specific for myositis compared to genetic muscle disease.

PubMed

Mammen, Andrew L; Casciola-Rosen, Livia; Christopher-Stine, Lisa; Lloyd, Thomas E; Wagner, Kathryn R

2015-12-01

To determine the specificity of myositis-specific autoantibodies (MSAs) for autoimmune myopathy compared with inherited muscle diseases. Serum samples from 47 patients with genetically confirmed inherited muscle diseases were screened for the most common MSAs, including those recognizing TIF1γ, NXP2, Mi2, MDA5, Jo1, SRP, and HMGCR. We compared these results with the findings in a cohort of patients with dermatomyositis (DM) previously screened for anti-TIF1γ, -NXP2, -Mi2, -MDA5, and -Jo1. Overall, the presence of anti-TIF1γ, -NXP2, -Mi2, -MDA5, or -Jo1 was 96% specific and 67% sensitive for DM compared to patients with genetic muscle diseases. No patients with inherited muscle disease had anti-SRP or anti-HMGCR autoantibodies. Only 2 patients with genetic muscle disease had a MSA. One patient with anti-Mi2 autoantibodies had both genetically confirmed facioscapulohumeral dystrophy and dermatomyositis based on a typical skin rash and partial response to immunosuppressive medications. A second patient with anti-Jo-1 autoantibodies had both genetically defined limb-girdle muscular dystrophy type 2A (i.e., calpainopathy) and a systemic autoimmune process based on biopsy-confirmed lupus nephritis, sicca symptoms, and anti-Ro52 autoantibodies. The MSAs tested for in this study are highly specific for autoimmune muscle disease and are rarely, if ever, found in patients who only have genetic muscle disease. In patients with genetic muscle disease, the presence of a MSA should suggest the possibility of a coexisting autoimmune process.

Myositis-specific autoantibodies are specific for myositis compared to genetic muscle disease

PubMed Central

Casciola-Rosen, Livia; Christopher-Stine, Lisa; Lloyd, Thomas E.; Wagner, Kathryn R.

2015-01-01

Objective: To determine the specificity of myositis-specific autoantibodies (MSAs) for autoimmune myopathy compared with inherited muscle diseases. Methods: Serum samples from 47 patients with genetically confirmed inherited muscle diseases were screened for the most common MSAs, including those recognizing TIF1γ, NXP2, Mi2, MDA5, Jo1, SRP, and HMGCR. We compared these results with the findings in a cohort of patients with dermatomyositis (DM) previously screened for anti-TIF1γ, -NXP2, -Mi2, -MDA5, and -Jo1. Results: Overall, the presence of anti-TIF1γ, -NXP2, -Mi2, -MDA5, or -Jo1 was 96% specific and 67% sensitive for DM compared to patients with genetic muscle diseases. No patients with inherited muscle disease had anti-SRP or anti-HMGCR autoantibodies. Only 2 patients with genetic muscle disease had a MSA. One patient with anti-Mi2 autoantibodies had both genetically confirmed facioscapulohumeral dystrophy and dermatomyositis based on a typical skin rash and partial response to immunosuppressive medications. A second patient with anti-Jo-1 autoantibodies had both genetically defined limb-girdle muscular dystrophy type 2A (i.e., calpainopathy) and a systemic autoimmune process based on biopsy-confirmed lupus nephritis, sicca symptoms, and anti-Ro52 autoantibodies. Conclusions: The MSAs tested for in this study are highly specific for autoimmune muscle disease and are rarely, if ever, found in patients who only have genetic muscle disease. In patients with genetic muscle disease, the presence of a MSA should suggest the possibility of a coexisting autoimmune process. PMID:26668818

The effect of the inspiratory muscle training on functional ability in stroke patients.

PubMed

Jung, Nam-Jin; Na, Sang-Su; Kim, Seung-Kyu; Hwangbo, Gak

2017-11-01

[Purpose] This study was to find out an inspiratory muscle training (IMT) program therapeutic effects on stroke patients' functional ability. [Subjects and Methods] Twenty stroke patients were assigned to one of two groups: inspiratory muscle training (n=10), and control (n=10), randomization. The inspiratory muscle training participants undertook an exercise program for 30 minute per times, 5 times a week for 6 weeks. The investigator measured the patients' trunk impairment scale (TIS) and 6 minute walking test (6MW) for functional ability before and after IMT. [Results] The TIS appeared some significant differences in both groups before and after the training. The 6MW test showed some significant differences in the inspiratory muscle training group, but didn't show any significant difference in the control group. And the differences in both groups after depending the inspiratory muscle training were significantly found in the tests of TIS and 6MW test [Conclusion] The results showed that the inspiratory muscle training in stroke patients are correlated with the trunk stability and locomotion ability, suggesting that physical therapist must take into consideration the inspiratory muscle training, as well as functional training to improve physical function in stroke patients.

Effects of Combined Treatment with Branched-Chain Amino Acids, Citric Acid, L-Carnitine, Coenzyme Q10, Zinc, and Various Vitamins in Tumor-Bearing Mice.

PubMed

Awa, Hiroko; Futamura, Akihiko; Higashiguchi, Takashi; Ito, Akihiro; Mori, Naoharu; Murai, Miyo; Ohara, Hiroshi; Chihara, Takeshi; Kaneko, Takaaki

2017-03-01

A functional dietary supplement (FDS) containing Coenzyme Q10, branched-chain amino acids and L-carnitine was administered to tumor-bearing mice, investigating its effects on tumor and muscle tissues. Experiment (A): B16 melanoma cells were implanted subcutaneously into the right side of the abdomen of 8- to 9-week-old C57BL/6J mice. The mice were divided into two groups: a FDS group that received oral administration of FDS (n=10), and a control group that received oral administration of glucose (n=10). The moribund condition was used as the endpoint, and median survival time was determined. Experiment (B): On day 21 after tumor implantation, tumors, soleus muscle, gastrocnemius muscle, and suprahyoid muscles were collected. Tumor and muscle weight and other aspects were evaluated in each group: FDS group (n=15) and control group (n=15). The median survival time was comparable (21 d in the FDS group vs. 18 d in the control group, p=0.30). However, cumulative food intake was significantly higher in the FDS group than the control group (p=0.011). Metastasis of melanoma to the lung was observed in the control group but not in the FDS group (p=0.043). The weight of the suprahyoid muscles was significantly higher in the FDS group than in the control group (p=0.0045). The weight of the tumor was significantly lower in the FDS group than in the control group (p=0.013). The results possibly suggest oral administration of FDS in tumor-bearing mice enhances the maintenance of suprahyoid muscles, resulting in an extended feeding period and suppression of tumor growth and metastasis.

Regulation of gene expression mediating indeterminate muscle growth in teleosts.

PubMed

Ahammad, A K Shakur; Asaduzzaman, Md; Asakawa, Shuichi; Watabe, Shugo; Kinoshita, Shigeharu

2015-08-01

Teleosts are unique among vertebrates due to their indeterminate muscle growth, i.e., continued production of neonatal muscle fibers until death. However, the molecular mechanism(s) underlying this property is unknown. Here, we focused on the torafugu (Takifugu rubripes) myosin heavy chain gene, MYHM2528-1, which is specifically expressed in neonatal muscle fibers produced by indeterminate muscle growth. We examined the flanking region of MYHM2528-1 through an in vivo reporter assay using zebrafish (Danio rerio) and identified a 2100 bp 5'-flanking sequence that contained sufficient promoter activity to allow specific gene expression. The effects of enhanced promoter activity were observed at the outer region of the fast muscle and the dorsal edge of slow muscle in zebrafish larvae. At the juvenile stage, the promoter was specifically activated in small diameter muscle fibers scattered throughout fast muscle and in slow muscle near the septum separating slow and fast muscles. This spatio-temporal promoter activity overlapped with known myogenic zones involved in teleost indeterminate muscle growth. A deletion mutant analysis revealed that the -2100 to -600 bp 5'flanking sequence of MYHM2528-1 is essential for promoter activity. This region contains putative binding sites for several representative myogenesis-related transcription factors and nuclear factor of activated T-cell (NFAT), a transcription activator involved in regeneration of mammalian adult skeletal muscle. A significant reduction in the promoter activity of the MYHM2528-1 deletion constructs was observed in accordance with a reduction in the number of these binding sites, suggesting the involvement of specific transcription factors in indeterminate muscle growth. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A comparison of water-based and land-based core stability exercises in patients with lumbar disc herniation: a pilot study.

PubMed

Bayraktar, Deniz; Guclu-Gunduz, Arzu; Lambeck, Johan; Yazici, Gokhan; Aykol, Sukru; Demirci, Harun

2016-01-01

To determine and compare the effects of core stability exercise programs performed in two different environments in lumbar disc herniation (LDH) patients. Thirty-one patients who were diagnosed with LDH and were experiencing pain or functional disability for at least 3 months were randomly divided into two groups as land-based exercises or water specific therapy. Also, 15 age-sex-matched healthy individuals were recruited as healthy controls. Both groups underwent an 8-week (3 times/week) core stabilization exercise program. Primary outcomes were pain, trunk muscle static endurance and perceived disability level. The secondary outcome was health-related quality of life. Level of static endurance of trunk muscles was found to be lower in the patients compared to the controls at baseline (p < 0.05). Both treatment groups showed significant improvements in all outcomes (p < 0.05) after 8-week intervention. When two treatment groups were compared, no differences were found in the amount of change after the intervention (p > 0.05). After the treatment, static endurance of trunk muscles of the LDH patients became similar to controls (p > 0.05). According to these results, core stabilization exercise training performed on land or in water both could be beneficial in LDH patients and there is no difference between the environments. An 8-week core stabilization program performed in water or on land decrease pain level and improve functional status in LDH patients. Both programs seem beneficial to increase health-related quality of life and static endurance of trunk muscles. Core stability exercises could be performed in water as well, no differences were found between methods due to environment.