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Sample records for abdominal muscle activity

  1. 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…

  2. Trunk Muscle Activities During Abdominal Bracing: Comparison Among Muscles and Exercises

    PubMed Central

    Maeo, Sumiaki; Takahashi, Takumi; Takai, Yohei; Kanehisa, Hiroaki

    2013-01-01

    Abdominal bracing is often adopted in fitness and sports conditioning programs. However, there is little information on how muscular activities during the task differ among the muscle groups located in the trunk and from those during other trunk exercises. The present study aimed to quantify muscular activity levels during abdominal bracing with respect to muscle- and exercise-related differences. Ten healthy young adult men performed five static (abdominal bracing, abdominal hollowing, prone, side, and supine plank) and five dynamic (V- sits, curl-ups, sit-ups, and back extensions on the floor and on a bench) exercises. Surface electromyogram (EMG) activities of the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinae (ES) muscles were recorded in each of the exercises. The EMG data were normalized to those obtained during maximal voluntary contraction of each muscle (% EMGmax). The % EMGmax value during abdominal bracing was significantly higher in IO (60%) than in the other muscles (RA: 18%, EO: 27%, ES: 19%). The % EMGmax values for RA, EO, and ES were significantly lower in the abdominal bracing than in some of the other exercises such as V-sits and sit-ups for RA and EO and back extensions for ES muscle. However, the % EMGmax value for IO during the abdominal bracing was significantly higher than those in most of the other exercises including dynamic ones such as curl-ups and sit-ups. These results suggest that abdominal bracing is one of the most effective techniques for inducing a higher activation in deep abdominal muscles, such as IO muscle, even compared to dynamic exercises involving trunk flexion/extension movements. Key Points Trunk muscle activities during abdominal bracing was examined with regard to muscle- and exercise-related differences. Abdominal bracing preferentially activates internal oblique muscles even compared to dynamic exercises involving trunk flexion/extension movements. Abdominal bracing should be

  3. Effect of craniocervical posture on abdominal muscle activities

    PubMed Central

    Su, Jung Gil; Won, Shin Ji; Gak, Hwangbo

    2016-01-01

    [Purpose] The aim of this study was to investigate the influence of the craniocervical posture on abdominal muscle activities in hook-lying position. [Subjects] This study recruited 12 healthy young adults. [Methods] Each subject was asked to adopt a supine position with the hip and knee flexed at 60°. Surface electromyographic signals of transversus abdominis/internal oblique, rectus abdominis, and external oblique in different craniocervical postures (extension, neutral, and flexion) were compared. [Results] The transversus abdominis and rectus abdominis showed increased muscle activities in craniocervical flexion compared to craniocervical extension and neutral position. Greater muscle activities of the external oblique were seen in craniocervical flexion than in craniocervical extension. [Conclusion] Craniocervical flexion was found to be effective to increase the abdominal muscle activities. Consideration of craniocervical posture is recommended when performing trunk stabilization exercises. PMID:27065558

  4. ABDOMINAL MUSCLE ACTIVATION INCREASES LUMBAR SPINAL STABILITY: ANALYSIS OF CONTRIBUTIONS OF DIFFERENT MUSCLE GROUPS

    PubMed Central

    Stokes, Ian A.F.; Gardner-Morse, Mack G.; Henry, Sharon M.

    2011-01-01

    Background Antagonistic activation of abdominal muscles and raised intra-abdominal pressure are associated with both spinal unloading and spinal stabilization. Rehabilitation regimens have been proposed to improve spinal stability via selective recruitment of certain trunk muscle groups. This biomechanical study used an analytical model to address whether lumbar spinal stability is increased by selective activation of abdominal muscles. Methods The biomechanical model included anatomically realistic three-layers of curved abdominal musculature connected by fascia, rectus abdominis and 77 symmetrical pairs of dorsal muscles. The muscle activations were calculated with the model loaded with either flexion, extension, lateral bending or axial rotation moments up to 60 Nm, along with intra-abdominal pressure up to 5 or 10 kPa (37.5 or 75 mm Hg) and partial bodyweight. After solving for muscle forces, a buckling analysis quantified spinal stability. Subsequently, different patterns of muscle activation were studied by forcing activation of selected abdominal muscles to at least 10% or 20% of maximum. Findings The spinal stability increased by an average factor of 1.8 with doubling of intra-abdominal pressure. Forced activation of obliques or transversus abdominis muscles to at least 10% of maximum increased stability slightly for efforts other than flexion, but forcing at least 20% activation generally did not produce further increase in stability. Forced activation of rectus abdominis did not increase stability. Interpretation Based on predictions from an analytical spinal buckling model, the degree of stability was not substantially influenced by selective forcing of muscle activation. This casts doubt on the supposed mechanism of action of specific abdominal muscle exercise regimens that have been proposed for low back pain rehabilitation. PMID:21571410

  5. Expiratory abdominal muscle activity during ventilatory chemostimulation in piglets.

    PubMed

    Watchko, J F; O'Day, T L; Brozanski, B S; Guthrie, R D

    1990-04-01

    We examined abdominal muscle minute electromyographic (EMG) activity (peak moving time average EMG x respiratory rate) during eupnea, hyperoxic hypercapnia (8% CO2-40% O2-balance N2), and hypoxia (13% O2) in 12 anesthetized (0.5% halothane) newborn piglets. In addition, we assessed the role of vagal afferent pathways in the abdominal muscles' response to ventilatory chemostimulation by examining abdominal EMG activity (EMGab) before and after bilateral cervical vagotomy in five animals. Phasic expiratory EMGab was observed in 11 of 12 piglets during eupnea. Hypercapnia was associated with a sustained augmentation of minute EMGab (444 +/- 208% control). In contrast, hypoxia consistently augmented (1 min, 193 +/- 33% control) then diminished (5 min, 126 +/- 39% control) minute EMGab. Vagotomy resulted in a decline in peak moving time average EMGab by approximately one-half (48 +/- 18% control); the abdominal muscles' response to ventilatory chemostimulation, however, was qualitatively unchanged. We conclude that 1) expiration during eupnea in anesthetized newborn piglets is associated with phasic EMGab; 2) both hypercapnia and hypoxia augment minute EMGab; however, only hypercapnia is associated with sustained augmentation; and 3) although vagal afferents have a role in modulating the base-line level of EMGab, other extravagal mechanisms appear to determine the pattern of EMGab in response to ventilatory chemostimulation.

  6. Some effects of vagal blockade on abdominal muscle activation and shortening in awake dogs.

    PubMed Central

    Leevers, A M; Road, J D

    1995-01-01

    1. The mechanisms of abdominal muscle activation are thought to be different during expiratory threshold loading (ETL) compared with hypercapnia. Our objectives in the present study were to determine the effects of removing excitatory vagal feedback on abdominal muscle activation, shortening and pattern of recruitment during ETL and hypercapnia. Six tracheotomized dogs were chronically implanted with sonomicrometer transducers and fine wire EMG electrodes in each of the four abdominal muscles. Muscle length changes and EMG activity were studied in the awake dog during ETL (6 dogs) and CO2 rebreathing (3 dogs), before and after vagal blockade. 2. Following vagal blockade, the change in volume (increase in functional residual capacity, FRC) during ETL was greater and active phasic shortening of all the abdominal muscles was reduced, when shortening was compared with a similar change in lung volume. Similarly, at comparable minute ventilation, abdominal muscle active shortening was also reduced during hypercapnia. The internal muscle layer was recruited preferentially in both control and vagally blocked dogs during both ETL and hypercapnia. 3. The degree of recruitment of the abdominal muscles during ETL and hypercapnia in awake dogs is influenced by vagal feedback, but less so than in anaesthetized dogs. These results illustrate the importance of the vagi and abdominal muscle activation in load compensation. However, vagal reflexes are apparently not contributing to the preferential recruitment of the internal muscle layer. In awake dogs during vagal blockade abdominal muscle recruitment still occurs by extravagal mechanisms. PMID:8568685

  7. Abdominal muscle activity according to knee joint angle during sit-to-stand

    PubMed Central

    Eom, Juri; Rhee, Min-Hyung; Kim, Laurentius Jongsoon

    2016-01-01

    [Purpose] This study assessed the activity of the abdominal muscles according to the angle of the knee joints during sit-to-stand. [Subjects and Methods] Thirty healthy adult males participated in this study. Subjects initiated sit-to-stand at knee joint angles of 60°, 90°, or 120°. An electromyography system was used to measure the maximum voluntary isometric contraction of the rectus abdominis, external oblique, and internal oblique and transverse abdominis muscles. [Results] Percent contraction differed significantly among the three knee joint angles, most notably for the internal oblique and transverse abdominis muscles. [Conclusion] Wider knee joint angles more effectively activate the abdominal muscles, especially those in the deep abdomen, than do narrower angles. PMID:27390431

  8. Influence of pelvis position on the activation of abdominal and hip flexor muscles.

    PubMed

    Workman, J Chad; Docherty, David; Parfrey, Kevin C; Behm, David G

    2008-09-01

    A pelvic position has been sought that optimizes abdominal muscle activation while diminishing hip flexor activation. Thus, the objective of the study was to investigate the effect of pelvic position and the Janda sit-up on trunk muscle activation. Sixteen male volunteers underwent electromyographic (EMG) testing of their abdominal and hip flexor muscles during a supine isometric double straight leg lift (DSLL) with the feet held approximately 5 cm above a board. The second exercise (Janda sit-up) was a sit-up action where participants simultaneously contracted the hamstrings and the abdominal musculature while holding an approximately 45 degrees angle at the knee. Root mean square surface electromyography was calculated for the Janda sit-up and DSLL under 3 pelvic positions: anterior, neutral, and posterior pelvic tilt. The selected muscles were the upper and lower rectus abdominis (URA, LRA), external obliques, lower abdominal stabilizers (LAS), rectus femoris, and biceps femoris. The Janda sit-up position demonstrated the highest URA and LRA activation and the lowest rectus femoris activation. The Janda sit-up and the posterior tilt were significantly greater (p < 0.01 and p < 0.05, respectively) than the anterior tilt for the URA and LRA muscles. Activation levels of the URA and LRA in neutral pelvis were significantly (p < 0.01 and p < 0.05, respectively) less than the Janda sit-up position, but not significantly different from the posterior tilt. No significant differences in EMG activity were found for the external obliques or LAS. No rectus femoris differences were found in the 3 pelvis positions. The results of this study indicate that pelvic position had a significant effect on the activation of selected trunk and hip muscles during isometric exercise, and the activation of the biceps femoris during the Janda sit-up reduced the activation of the rectus femoris while producing high levels of activation of the URA and LRA.

  9. Slow expiration reduces sternocleidomastoid activity and increases transversus abdominis and internal oblique muscle activity during abdominal curl-up.

    PubMed

    Yoon, Tae-Lim; Kim, Ki-Song; Cynn, Heon-Seock

    2014-04-01

    The aim of this study was to investigate the effects of quiet inspiration versus slow expiration on sternocleidomastoid (SCM) and abdominal muscle activity during abdominal curl-up in healthy subjects. Twelve healthy subjects participated in this study. Surface electromyography (EMG) was used to collect activity of bilateral SCM, rectus abdominis (RA), external oblique (EO), and transversus abdominis/internal oblique (TrA/IO) muscles. A paired t-test was used to determine significant differences in the bilateral SCM, RF, EO, and TrA/IO muscles between abdominal curl-up with quiet inspiration and slow expiration. There were significantly lower EMG activity of both SCMs and greater EMG activity of both IOs during abdominal curl-up with slow expiration, compared with the EMG activity of both SCMs and IOs during abdominal curl-up with quiet inspiration (p<.05). The results of this study suggest that slow expiration would be recommended during abdominal curl-up for reduced SCM activation and selective activation of TrA/IO in healthy subjects compared with those in abdominal curl up with quiet inspiration.

  10. Control of abdominal and expiratory intercostal muscle activity during vomiting - Role of ventral respiratory group expiratory neurons

    NASA Technical Reports Server (NTRS)

    Miller, Alan D.; Tan, L. K.; Suzuki, Ichiro

    1987-01-01

    The role of ventral respiratory group (VRG) expiratory (E) neurons in the control of abdominal and internal intercostal muscle activity during vomiting was investigated in cats. Two series of experiments were performed: in one, the activity of VRG E neurons was recorded during fictive vomiting in cats that were decerebrated, paralyzed, and artificially ventilated; in the second, the abdominal muscle activity during vomiting was compared before and after sectioning the axons of descending VRG E neurons in decerebrate spontaneously breathing cats. The results show that about two-thirds of VRG E neurons that project at least as far caudally as the lower thoracic cord contribute to internal intercostal muscle activity during vomiting. The remaining VRG E neurons contribute to abdominal muscle activation. As shown by severing the axons of the VRG E neurons, other, as yet unidenified, inputs (either descending from the brain stem or arising from spinal reflexes) can also produce abdominal muscle activation.

  11. Influence of Hamstring and Abdominal Muscle Activation on a Positive Ober's Test in People with Lumbopelvic Pain

    PubMed Central

    Tenney, H. Rich; DeBord, Aaron

    2013-01-01

    ABSTRACT Purpose: To assess the immediate effect of hamstring and abdominal activation on pain levels as measured by the Numeric Pain Scale (NPS) and hip range of motion as measured by Ober's Test in people with lumbopelvic pain. Methods: Thirteen participants with lumbopelvic pain and positive Ober's Tests completed an exercise developed by the Postural Restoration Institute™ to recruit hamstrings and abdominal muscles. Results: There was a significant increase in passive hip-adduction angles (p<0.01) and decrease in pain (p<0.01) immediately after the intervention. Conclusion: Specific exercises that activate hamstrings and abdominal muscles appear to immediately improve Ober's Test measurements and reduce pain as measured by the NPS in people with lumbo-pelvic pain. Hamstring/abdominal activation, rather than iliotibial band stretching, may be an effective intervention for addressing lumbopelvic pain and a positive Ober's Test. PMID:24381375

  12. The difference between standing and sitting in 3 different seat inclinations on abdominal muscle activity and chest and abdominal expansion in woodwind and brass musicians

    PubMed Central

    Ackermann, Bronwen J.; O'Dwyer, Nicholas; Halaki, Mark

    2014-01-01

    Wind instrumentalists require a sophisticated functioning of their respiratory system to control their air stream, which provides the power for optimal musical performance. The air supply must be delivered into the instrument in a steady and controlled manner and with enough power by the action of the expiratory musculature to produce the desired level of sound at the correct pitch. It is suggested that playing posture may have an impact on the abdominal muscle activity controlling this expired air, but there is no research on musicians to support this theory. This study evaluated chest and abdominal expansion, via respiratory inductive plethysmography, as well as activation patterns of lower and upper abdominal musculature, using surface electromyography, during performance of a range of typical orchestral repertoire by 113 woodwind and brass players. Each of the five orchestral excerpts was played in one of four randomly allocated postures: standing; sitting flat; sitting inclined forwards; and sitting inclined backwards. Musicians showed a clear preference for playing in standing rather than sitting. In standing, the chest expansion range and maximum values were greater (p < 0.01), while the abdominal expansion was less than in all sitting postures (p < 0.01). Chest expansion patterns did not vary between the three sitting postures, while abdominal expansion was reduced in the forward inclined posture compared to the other sitting postures (p < 0.05). There was no significant variation in abdominal muscle activation between the sitting postures, but the level of activation in sitting was only 2/3 of the significantly higher level observed in standing (p < 0.01). This study has demonstrated significant differences in respiratory mechanics between sitting and standing postures in wind musicians during playing of typical orchestral repertoire. Further research is needed to clarify the complex respiratory mechanisms supporting musical performance. PMID:25202290

  13. The difference between standing and sitting in 3 different seat inclinations on abdominal muscle activity and chest and abdominal expansion in woodwind and brass musicians.

    PubMed

    Ackermann, Bronwen J; O'Dwyer, Nicholas; Halaki, Mark

    2014-01-01

    Wind instrumentalists require a sophisticated functioning of their respiratory system to control their air stream, which provides the power for optimal musical performance. The air supply must be delivered into the instrument in a steady and controlled manner and with enough power by the action of the expiratory musculature to produce the desired level of sound at the correct pitch. It is suggested that playing posture may have an impact on the abdominal muscle activity controlling this expired air, but there is no research on musicians to support this theory. This study evaluated chest and abdominal expansion, via respiratory inductive plethysmography, as well as activation patterns of lower and upper abdominal musculature, using surface electromyography, during performance of a range of typical orchestral repertoire by 113 woodwind and brass players. Each of the five orchestral excerpts was played in one of four randomly allocated postures: standing; sitting flat; sitting inclined forwards; and sitting inclined backwards. Musicians showed a clear preference for playing in standing rather than sitting. In standing, the chest expansion range and maximum values were greater (p < 0.01), while the abdominal expansion was less than in all sitting postures (p < 0.01). Chest expansion patterns did not vary between the three sitting postures, while abdominal expansion was reduced in the forward inclined posture compared to the other sitting postures (p < 0.05). There was no significant variation in abdominal muscle activation between the sitting postures, but the level of activation in sitting was only 2/3 of the significantly higher level observed in standing (p < 0.01). This study has demonstrated significant differences in respiratory mechanics between sitting and standing postures in wind musicians during playing of typical orchestral repertoire. Further research is needed to clarify the complex respiratory mechanisms supporting musical performance.

  14. Comparison of EMG activity on abdominal muscles during plank exercise with unilateral and bilateral additional isometric hip adduction.

    PubMed

    Kim, Soo-Yong; Kang, Min-Hyeok; Kim, Eui-Ryong; Jung, In-Gui; Seo, Eun-Young; Oh, Jae-Seop

    2016-10-01

    The aim of this study was to investigate the effects of additional isometric hip adduction during the plank exercise on the abdominal muscles. Twenty healthy young men participated in this study. Surface electromyography (EMG) was used to monitor the activity of the bilateral rectus abdominis (RA), the internal oblique (IO), and the external oblique (EO) muscles. The participants performed three types of plank exercise; the standard plank exercise, the plank exercise with bilateral isometric hip adduction, and the plank exercise with unilateral isometric hip adduction. All abdominal muscle activity was significantly increased during the plank exercise combined with the bilateral and unilateral isometric hip adduction compared with the standard plank exercise (p<0.05). Bilateral IO, EO, and left RA muscle activity was significantly increased during the unilateral isometric hip adduction compared with the bilateral isometric hip adduction (p<0.05). These findings suggest that additional isometric hip adduction during the plank exercise could be a useful method to enhance abdominal muscle activity. In particular, the unilateral isometric hip adduction is a more beneficial exercise than the bilateral isometric hip adduction.

  15. Comparison of deep and superficial abdominal muscle activity between experienced Pilates and resistance exercise instructors and controls during stabilization exercise

    PubMed Central

    Moon, Ji-Hyun; Hong, Sang-Min; Kim, Chang-Won; Shin, Yun-A

    2015-01-01

    Pilates and resistance exercises are used for lumbar stabilization training. However, it is unclear which exercise is more effective for lumbar stabilization. In our study, we aimed to compare surface muscle activity and deep muscle thickness during relaxation and spinal stabilization exercise in experienced Pilates and resistance exercise instructors. This study is a retrospective case control study set in the Exercise Prescription Laboratory and Sports Medicine Center. The participants included Pilates instructors (mean years of experience, 3.20±1.76; n=10), resistance exercise instructors (mean years of experience, 2.53±0.63; n=10), and controls (n=10). The participants performed 4 different stabilization exercises: abdominal drawing-in maneuver, bridging, roll-up, and one-leg raise. During the stabilization exercises, surface muscle activity was measured with electromyography, whereas deep muscle thickness was measured by ultrasound imaging. During the 4 stabilization exercises, the thickness of the transverse abdominis (TrA) was significantly greater in the Pilates-trained group than the other 2 other groups. The internal oblique (IO) thickness was significantly greater in the Pilates- and resistance-trained group than the control group, during the 4 exercises. However, the surface muscle activities were similar between the groups. Both Pilates and resistance exercise instructors had greater activation of deep muscles, such as the TrA and IO, than the control subjects. Pilates and resistance exercise are both effective for increasing abdominal deep muscle thickness. PMID:26171383

  16. Comparison of deep and superficial abdominal muscle activity between experienced Pilates and resistance exercise instructors and controls during stabilization exercise.

    PubMed

    Moon, Ji-Hyun; Hong, Sang-Min; Kim, Chang-Won; Shin, Yun-A

    2015-06-01

    Pilates and resistance exercises are used for lumbar stabilization training. However, it is unclear which exercise is more effective for lumbar stabilization. In our study, we aimed to compare surface muscle activity and deep muscle thickness during relaxation and spinal stabilization exercise in experienced Pilates and resistance exercise instructors. This study is a retrospective case control study set in the Exercise Prescription Laboratory and Sports Medicine Center. The participants included Pilates instructors (mean years of experience, 3.20±1.76; n=10), resistance exercise instructors (mean years of experience, 2.53±0.63; n=10), and controls (n=10). The participants performed 4 different stabilization exercises: abdominal drawing-in maneuver, bridging, roll-up, and one-leg raise. During the stabilization exercises, surface muscle activity was measured with electromyography, whereas deep muscle thickness was measured by ultrasound imaging. During the 4 stabilization exercises, the thickness of the transverse abdominis (TrA) was significantly greater in the Pilates-trained group than the other 2 other groups. The internal oblique (IO) thickness was significantly greater in the Pilates- and resistance-trained group than the control group, during the 4 exercises. However, the surface muscle activities were similar between the groups. Both Pilates and resistance exercise instructors had greater activation of deep muscles, such as the TrA and IO, than the control subjects. Pilates and resistance exercise are both effective for increasing abdominal deep muscle thickness.

  17. Contribution of abdominal muscle strength to various activities of daily living of stroke patients with mild paralysis.

    PubMed

    Fujita, Takaaki; Sato, Atsushi; Togashi, Yui; Kasahara, Ryuichi; Ohashi, Takuro; Yamamoto, Yuichi

    2015-03-01

    [Purpose] The trunk muscles frequently become weak after stroke, thus impacting overall activities of daily living. However, activities of daily living items closely related with trunk strength remain unclear. This study aimed to clarify the influence of trunk muscle weakness on activities of daily living items. [Subjects] The subjects were 24 stroke patients who fulfilled the following inclusion criteria: first stroke and the absence of severe paralysis, marked cognitive function deterioration, unilateral spatial neglect or apathy. [Methods] According to abdominal strength, the 24 patients were divided into a nonweakness group and a weakness group. For the assessment, we used the stroke impairment assessment set, the Berg balance scale, a simple test for evaluating hand function, grip strength, and functional independence measure scale scores and the results were compared between the groups. [Results] The Berg balance scale score and scores for dressing, toilet use, transfer to bed, and walk items of the functional independence measure were significantly lower in the weakness group than in the nonweakness group. [Conclusion] Our results suggest that weakness of the abdominal muscles adversely impacts the balance of patients with mild stroke as well as their ability to dress, use a toilet, transfer, and walk. Trunk training, including abdominal muscle exercises, can effectively improve the performance of these activities of daily living items.

  18. Changes in trunk muscle activation and lumbar-pelvic position associated with abdominal hollowing and reach during a simulated manual material handling task.

    PubMed

    Butler, Heather L; Hubley-Kozey, Cheryl L; Kozey, John W

    2007-03-01

    The purpose of this study was to investigate the effect of abdominal hollowing (AH) on trunk muscle activation and lumbar-pelvic motion during a controlled lift and replace task. Surface electromyograms were recorded from five abdominal and two back muscle sites. Sagittal lumbar-pelvic motion was recorded by video. Subjects lifted a 3.8 kg load in normal, maximum and extreme reaches, first while performing their preferred lifting style (PLS) and then maintaining an AH technique. The external oblique muscle site activities were significantly higher (p < 0.05) for the AH technique (ranging from 7-20% of maximal voluntary activation (MVIC)) than at any of the abdominal sites for the PLS (ranging from 2-10% MVIC). Differences were found among abdominal sites for the AH, but not for the PLS. The back muscle site activities (ranging from 9-30% MVIC) were significantly higher (p < 0.05) than for any of the abdominal muscles for all conditions, except for the anterior external oblique for AH. The pelvic and lumbar angles changed significantly (p < 0.05) between normal and maximal reaches and between techniques. The AH technique altered abdominal muscle activation amplitudes, with minimal differences in trunk extensors compared to the PLS. The AH resulted in more posterior pelvic tilt.

  19. Fiber architecture of canine abdominal muscles.

    PubMed

    Boriek, Aladin M; Ortize, Jaime; Zhu, Deshen

    2002-02-01

    During respiration, abdominal muscles experience loads, not only in the muscle-fiber direction but also transverse to the fibers. We wondered whether the abdominal muscles exhibit a fiber architecture that is similar to the diaphragm muscle, and, therefore, we chose two adjacent muscles: the internal oblique (IO), with about the same muscle length as the diaphragm, and the transverse abdominis (TA), which is twice as long as the diaphragm. First, we used acetylcholinesterase staining to examine the distribution of neuromuscular junctions on both surfaces of the TA and IO muscles in six dogs. A maximum of four irregular bands of neuromuscular junctions crossed the IO, and as many as six bands crossed the TA, which is consistent with a discontinuous fiber architecture. In six additional dogs, we examined fiber architecture of these muscles by microdissecting 103 fascicles from the IO and 139 from the TA. Each fascicle contained between 20 and 30 muscle fibers. The mean length of nonspanning fibers (NSF) ranged from 2.8 +/- 0.3 cm in the IO to 4.3 +/- 0.5 cm in the TA, and the mean length of spanning fibers ranged from 4.3 +/- 0.5 cm in the IO to 7.6 +/- 1.4 cm in the TA. NSF accounted for 89.6 +/- 1.5% of all fibers dissected from the IO and 99.1 +/- 0.2% of all fibers dissected from the TA. The percentage of NSF with both ends tapered was 6.2 +/- 1.0 and 41.0 +/- 2.3% for IO and TA, respectively. These data show that fiber architecture in either IO or TA is discontinuous, with much more short-tapered fibers in the TA than in the IO. When abdominal muscles are submaximally activated, as during both normal expiration and maximal expiratory efforts, muscle force could be transmitted to the cell membrane and to the extracellular intramuscular connective tissue by shear linkage, presumably via structural transmembrane proteins.

  20. Effect of neck flexion restriction on sternocleidomastoid and abdominal muscle activity during curl-up exercises.

    PubMed

    Lee, Dong-Kyu; Moon, Dong-Chul; Hong, Ki-Hoon

    2016-01-01

    [Purpose] The purpose of this study was to investigate the effect of neck flexion restriction on sternocleidomastoid (SCM), rectus abdominis (RA), and external oblique (EO) muscle activity during a traditional curl-up exercise and a curl-up with neck flexion restriction. [Subjects] In total, 13 healthy male subjects volunteered for this study. [Methods] All subjects performed a traditional curl-up exercise and a curl-up exercise in which neck flexion was restricted by the subject's hand. Surface electromyography (EMG) signals were recorded from the SCM, RA, and EO during the curl-up. [Results] There was significantly lower EMG activity of the SCM during the curl-up exercise with neck flexion restriction compared to the traditional curl-up exercise. Conversely, the activity of the RA and EO muscles was significantly higher in the curl-up exercise with neck flexion restriction than in the traditional curl-up exercise. [Conclusion] Neck flexion restriction is recommended to prevent excessive activation of superficial cervical flexors during the curl-up exercise.

  1. Effect of neck flexion restriction on sternocleidomastoid and abdominal muscle activity during curl-up exercises

    PubMed Central

    Lee, Dong-Kyu; Moon, Dong-Chul; Hong, Ki-Hoon

    2016-01-01

    [Purpose] The purpose of this study was to investigate the effect of neck flexion restriction on sternocleidomastoid (SCM), rectus abdominis (RA), and external oblique (EO) muscle activity during a traditional curl-up exercise and a curl-up with neck flexion restriction. [Subjects] In total, 13 healthy male subjects volunteered for this study. [Methods] All subjects performed a traditional curl-up exercise and a curl-up exercise in which neck flexion was restricted by the subject’s hand. Surface electromyography (EMG) signals were recorded from the SCM, RA, and EO during the curl-up. [Results] There was significantly lower EMG activity of the SCM during the curl-up exercise with neck flexion restriction compared to the traditional curl-up exercise. Conversely, the activity of the RA and EO muscles was significantly higher in the curl-up exercise with neck flexion restriction than in the traditional curl-up exercise. [Conclusion] Neck flexion restriction is recommended to prevent excessive activation of superficial cervical flexors during the curl-up exercise. PMID:26957735

  2. The Influence of Dual Pressure Biofeedback Units on Pelvic Rotation and Abdominal Muscle Activity during the Active Straight Leg Raise in Women with Chronic Lower Back Pain.

    PubMed

    Noh, Kyung-Hee; Kim, Ji-Won; Kim, Gyoung-Mo; Ha, Sung-Min; Oh, Jae-Seop

    2014-05-01

    [Purpose] This study was performed to assess the influence of applying dual pressure biofeedback units (DPBUs) on the angle of pelvic rotation and abdominal muscle activity during the active straight leg raise (ASLR). [Subjects] Seventeen patients with low-back pain (LBP) participated in this study. [Methods] The subjects were asked to perform an active straight leg raise (ASLR) without a PBU, with a single PBU, and with DPBUs. The angles of pelvic rotation were measured using a three-dimensional motion-analysis system, and the muscle activity of the bilateral internal oblique abdominis (IO), external oblique abdominis (EO), and rectus abdominis (RA) was recorded using surface electromyography (EMG). One-way repeated-measures ANOVA was performed to determine the rotation angles and muscle activity under the three conditions. [Results] The EMG activity of the ipsilateral IO, contralateral EO, and bilateral RA was greater and pelvic rotation was lower with the DPBUs than with no PBU or a single PBU. [Conclusion] The results of this study suggest that applying DPBUs during ASLR is effective in decreasing unwanted pelvic rotation and increasing abdominal muscle activity in women with chronic low back pain.

  3. Abdominal muscle and quadriceps strength in chronic obstructive pulmonary disease

    PubMed Central

    Man, W; Hopkinson, N; Harraf, F; Nikoletou, D; Polkey, M; Moxham, J

    2005-01-01

    Background: Quadriceps muscle weakness is common in chronic obstructive pulmonary disease (COPD) but is not observed in a small hand muscle (adductor pollicis). Although this could be explained by reduced activity in the quadriceps, the observation could also be explained by anatomical location of the muscle or fibre type composition. However, the abdominal muscles are of a similar anatomical and fibre type distribution to the quadriceps, although they remain active in COPD. Cough gastric pressure is a recently described technique that assesses abdominal muscle (and hence expiratory muscle) strength more accurately than traditional techniques. A study was undertaken to test the hypothesis that more severe weakness exists in the quadriceps than in the abdominal muscles of patients with COPD compared with healthy elderly controls. Methods: Maximum cough gastric pressure and quadriceps isometric strength were measured in 43 patients with stable COPD and 25 healthy elderly volunteers matched for anthropometric variables. Results: Despite a significant reduction in mean quadriceps strength (29.9 kg v 41.2 kg; 95% CI –17.9 to –4.6; p = 0.001), cough gastric pressure was preserved in patients with COPD (227.3 cm H2O v 204.8 cm H2O; 95% CI –5.4 to 50.6; p = 0.11). Conclusions: Abdominal muscle strength is preserved in stable COPD outpatients in the presence of quadriceps weakness. This suggests that anatomical location and fibre type cannot explain quadriceps weakness in COPD. By inference, we conclude that disuse and consequent deconditioning are important factors in the development of quadriceps muscle weakness in COPD patients, or that activity protects the abdominal muscles from possible systemic myopathic processes. PMID:15923239

  4. Load compensating responses of human abdominal muscles

    PubMed Central

    Lansing, R. W.; Meyerink, L.

    1981-01-01

    interval. Because of these similarities we suggest that the phase I reaction was a learned response of a `simple reaction time' type, and not comparable to late stretch reflexes such as the M2 of limb muscles. 6. Arm muscle responses to respiratory pressure changes were measured in three subjects under identical conditions used to obtain load reaction times of abdominal muscles. These simple reaction times averaged 61-71 msec, and ranged from 42 to 97 msec. Therefore very short proprioceptive reaction times are not peculiar to the respiratory system, or to load perturbations of the responding muscle. 7. Mechanical adjustments of airway pressure and lung volume in response to loading are first expressed at the mouth about 90 msec after abdominal muscle activity begins. In the `maintain position' task, the accuracy with which pressure and volume adjustments were made during the last 1.5 sec of the loading period approximated that reported in the literature for trained singers holding a tone using constant expiratory pressure. PMID:6459450

  5. Expiratory activation of abdominal muscle is associated with improved respiratory stability and an increase in minute ventilation in REM epochs of adult rats

    PubMed Central

    Andrews, Colin G.

    2015-01-01

    Breathing is more vulnerable to apneas and irregular breathing patterns during rapid eye movement (REM) sleep in both humans and rodents. We previously reported that robust and recurrent recruitment of expiratory abdominal (ABD) muscle activity is present in rats during REM epochs despite ongoing REM-induced muscle atonia in skeletal musculature. To develop a further understanding of the characteristics of ABD recruitment during REM epochs and their relationship with breathing patterns and irregularities, we sought to compare REM epochs that displayed ABD muscle recruitment with those that did not, within the same rats. Specifically, we investigated respiratory characteristics that preceded and followed recruitment. We hypothesized that ABD muscle recruitment would be likely to occur following respiratory irregularities and would subsequently contribute to respiratory stability and the maintenance of good ventilation following recruitment. Our data demonstrate that epochs of REM sleep containing ABD recruitments (REMABD+) were characterized by increased respiratory rate variability and increased presence of spontaneous brief central apneas. Within these epochs, respiratory events that displayed ABD muscle activation were preceded by periods of increased respiratory rate variability. Onset of ABD muscle activity increased tidal volume, amplitude of diaphragmatic contractions, and minute ventilation compared with the periods preceding ABD muscle activation. These results show that expiratory muscle activity is more likely recruited when respiration is irregular and its recruitment is subsequently associated with an increase in minute ventilation and a more regular respiratory rhythm. PMID:26338455

  6. An investigation of the reproducibility of ultrasound measures of abdominal muscle activation in patients with chronic non-specific low back pain.

    PubMed

    Costa, Leonardo Oliveira Pena; Maher, Chris G; Latimer, Jane; Hodges, Paul W; Shirley, Debra

    2009-07-01

    Ultrasound (US) measures are used by clinicians and researchers to evaluate improvements in activity of the abdominal muscles in patients with low back pain. Studies evaluating the reproducibility of these US measures provide some information; however, little is known about the reproducibility of these US measures over time in patients with low back pain. The objectives of this study were to estimate the reproducibility of ultrasound measurements of automatic activation of the lateral abdominal wall muscles using a leg force task in patients with chronic low back pain. Thirty-five participants from an existing randomised, blinded, placebo-controlled trial participated in the study. A reproducibility analysis was undertaken from all patients using data collected at baseline and after treatment. The reproducibility of measurements of thickness, muscle activation (thickness changes) and muscle improvement/deterioration after intervention (differences in thickness changes from single images made before and after treatment) was analysed. The reproducibility of static images (thickness) was excellent (ICC(2,1) = 0.97, 95% CI = 0.96-0.97, standard error of the measurement (SEM) = 0.04 cm, smallest detectable change (SDC) = 0.11 cm), the reproducibility of thickness changes was moderate (ICC(2,1) = 0.72, 95% CI 0.65-0.76, SEM = 15%, SDC 41%), while the reproducibility of differences in thickness changes from single images with statistical adjustment for duplicate measures was poor (ICC(2,1) = 0.44, 95% CI 0.33-0.58, SEM = 21%, SDC = 66.5%). Improvements in the testing protocol must be performed in order to enhance reproducibility of US as an outcome measure for abdominal muscle activation.

  7. Reliability of ultrasound in combination with surface electromyogram for evaluating the activity of abdominal muscles in individuals with and without low back pain.

    PubMed

    Yang, Kyung-Hye; Park, Du-Jin

    2014-08-01

    This study investigated the reliability of ultrasound in combination with surface electromyogram (EMG) for evaluating the activity of the abdominal muscles in individuals with and without low back pain during the abdominal drawing-in maneuver (ADIM). The study recruited ten individuals with or without low back pain, respectively. While the participants were performing the ADIM, the activities of the transversus abdominis (TrA) and the internal oblique (IO) were measured using ultra-sound, while the activities of the external oblique (EO) and the rectus abdominis (RA) were measured using surface EMG. Intra-class correlation coefficients (ICC) were used to verify the inter-rater reliability of ultrasound in combination with surface EMG at rest and during the ADIM, and Bland-Altman plots were used to verify intra-rater reliability. The inter-rater reliability for the two groups at rest and during the ADIM was excellent (ICC2,1 = 0.77-0.95). In the Bland-Altman plots, the mean differences and 95% limits of agreement in the abdominal muscles of the two groups at rest were -0.03∼0.03 mm (-0.66 to 0.60 mm) and -0.12∼ -0.05 (-0.58 to 0.48% MVIC), respectively. The mean differences and 95% limits of agreement in the abdominal muscles of the two groups during the ADIM were -0.04∼0.02 mm (-0.73 to 0.65 mm) and -0.19∼0.05% MVIC (-1.24 to 1.34% MVIC), respectively. The ultrasound in combination with surface EMG showed excellent inter-rater and intra-rater reliability at rest and during the ADIM.

  8. Appropriately placed surface EMG electrodes reflect deep muscle activity (psoas, quadratus lumborum, abdominal wall) in the lumbar spine.

    PubMed

    McGill, S; Juker, D; Kropf, P

    1996-11-01

    This study tested the possibility of obtaining the activity of deeper muscles in the torso-specifically psoas, quadratus lumborum, external oblique, internal oblique and transverse abdominis, using surface myoelectric electrodes. It was hypothesized that: (1) surface electrodes adequately represent the amplitude of deep muscles (specifically psoas, quadratus lumborum, external oblique, internal oblique, transverse abdominis); (2) a single surface electrode location would best represent the activation profiles of each deep muscle over a broad variety of tasks. We assumed that prediction of activation within 10% of maximum voluntary contraction (RMS difference between the surface and intramuscular channels), over the time history of the signal, was reasonable and acceptable to assist clinical interpretation of muscle activation amplitude, and ultimately for modeled estimates of muscle force. Surface electrodes were applied and intramuscular electrodes were inserted on the left side of the body in five men and three women who then performed a wide variety of flexor tasks (bent knee and straight leg situps and leg raises, curl ups), extensor tasks (including lifting barbells up to 70 kg), lateral bending tasks (standing lateral bend and horizontal lying side support), twisting tasks (standing and sitting), and internal/external hip rotation. Using the criteria of RMS difference and the coefficient of determination (R2) to compare surface with intramuscular myoelectric signals, the results indicated that selected surface electrodes adequately represent the amplitude of deep muscles-always within 15% RMS difference, or less with the exception of psoas where differences up to 20% were observed but only in certain maximum voluntary contraction efforts. It appears reasonable for spine modelers, and particularly clinicians, to assume well selected surface electrode locations provide a representation of these deeper muscles-as long as they recognize the magnitude of error for

  9. Why Do Abdominal Muscles Sometimes Separate during Pregnancy?

    MedlinePlus

    ... Lifestyle Pregnancy week by week Why do abdominal muscles sometimes separate during pregnancy? Answers from Roger W. ... D. During pregnancy, the growing uterus stretches the muscles in the abdomen. This can cause the two ...

  10. Functional electrical stimulation to the abdominal wall muscles synchronized with the expiratory flow does not induce muscle fatigue

    PubMed Central

    Okuno, Yukako; Takahashi, Ryoichi; Sewa, Yoko; Ohse, Hirotaka; Imura, Shigeyuki; Tomita, Kazuhide

    2017-01-01

    [Purpose] Continuous electrical stimulation of abdominal wall muscles is known to induce mild muscle fatigue. However, it is not clear whether this is also true for functional electrical stimulation delivered only during the expiratory phase of breathing. This study aimed to examine whether or not intermittent electrical stimulation delivered to abdominal wall muscles induces muscle fatigue. [Subjects and Methods] The subjects were nine healthy adults. Abdominal electrical stimulation was applied for 1.5 seconds from the start of expiration and then turned off during inspiration. The electrodes were attached to both sides of the abdomen at the lower margin of the 12th rib. Abdominal electrical stimulation was delivered for 15 minutes with the subject in a seated position. Expiratory flow was measured during stimulus. Trunk flexor torque and electromyography activity were measured to evaluate abdominal muscle fatigue. [Results] The mean stimulation on/off ratio was 1:2.3. The declining rate of abdominal muscle torque was 61.1 ± 19.1% before stimulus and 56.5 ± 20.9% after stimulus, not significantly different. The declining rate of mean power frequency was 47.8 ± 11.7% before stimulus and 47.9 ± 10.2% after stimulus, not significantly different. [Conclusion] It was found that intermittent electrical stimulation to abdominal muscles synchronized with the expiratory would not induce muscle fatigue. PMID:28356636

  11. Functional electrical stimulation to the abdominal wall muscles synchronized with the expiratory flow does not induce muscle fatigue.

    PubMed

    Okuno, Yukako; Takahashi, Ryoichi; Sewa, Yoko; Ohse, Hirotaka; Imura, Shigeyuki; Tomita, Kazuhide

    2017-03-01

    [Purpose] Continuous electrical stimulation of abdominal wall muscles is known to induce mild muscle fatigue. However, it is not clear whether this is also true for functional electrical stimulation delivered only during the expiratory phase of breathing. This study aimed to examine whether or not intermittent electrical stimulation delivered to abdominal wall muscles induces muscle fatigue. [Subjects and Methods] The subjects were nine healthy adults. Abdominal electrical stimulation was applied for 1.5 seconds from the start of expiration and then turned off during inspiration. The electrodes were attached to both sides of the abdomen at the lower margin of the 12th rib. Abdominal electrical stimulation was delivered for 15 minutes with the subject in a seated position. Expiratory flow was measured during stimulus. Trunk flexor torque and electromyography activity were measured to evaluate abdominal muscle fatigue. [Results] The mean stimulation on/off ratio was 1:2.3. The declining rate of abdominal muscle torque was 61.1 ± 19.1% before stimulus and 56.5 ± 20.9% after stimulus, not significantly different. The declining rate of mean power frequency was 47.8 ± 11.7% before stimulus and 47.9 ± 10.2% after stimulus, not significantly different. [Conclusion] It was found that intermittent electrical stimulation to abdominal muscles synchronized with the expiratory would not induce muscle fatigue.

  12. Effect of head and limb orientation on trunk muscle activation during abdominal hollowing in chronic low back pain

    PubMed Central

    2014-01-01

    Background Individuals with chronic low back pain (CLBP) have altered activations patterns of the anterior trunk musculature when performing the abdominal hollowing manœuvre (attempt to pull umbilicus inward and upward towards the spine). There is a subgroup of individuals with CLBP who have high neurocognitive and sensory motor deficits with associated primitive reflexes (PR). The objective of the study was to determine if orienting the head and extremities to positions, which mimic PR patterns would alter anterior trunk musculature activation during the hollowing manoeuvre. Methods This study compared surface electromyography (EMG) of bilateral rectus abdominis (RA), external oblique (EO), and internal obliques (IO) of 11 individuals with CLBP and evident PR to 9 healthy controls during the hollowing manoeuvre in seven positions of the upper quarter. Results Using magnitude based inferences it was likely (>75%) that controls had a higher ratio of left IO:RA activation with supine (cervical neutral), asymmetrical tonic neck reflex (ATNR) left and right, right cervical rotation and cervical extension positions. A higher ratio of right IO:RA was detected in the cervical neutral and ATNR left position for the control group. The CLBP group were more likely to show higher activation of the left RA in the cervical neutral, ATNR left and right, right cervical rotation and cervical flexion positions as well as in the cervical neutral and cervical flexion position for the right RA. Conclusions Individuals with CLBP and PR manifested altered activation patterns during the hollowing maneuver compared to healthy controls and that altering cervical and upper extremity position can diminish the group differences. Altered cervical and limb positions can change the activation levels of the IO and EO in both groups. PMID:24558971

  13. Lateral abdominal muscle size at rest and during abdominal drawing-in manoeuvre in healthy adolescents.

    PubMed

    Linek, Pawel; Saulicz, Edward; Wolny, Tomasz; Myśliwiec, Andrzej; Kokosz, Mirosław

    2015-02-01

    Lateral abdominal wall muscles in children and adolescents have not been characterised to date. In the present report, we examined the reliability of the ultrasound measurement and thickness of the oblique external muscle (OE), oblique internal muscle (OI) and transverse abdominal muscle (TrA) at rest and during abdominal drawing-in manoeuvre (ADIM) on both sides of the body in healthy adolescents. We also determined possible differences between boys and girls and defined any factors-such as body mass, height and BMI-that may affect the thickness of the abdominal muscles. B-mode ultrasound was used to assess OE, OI and TrA on both sides of the body in the supine position. Ultrasound measurements at rest and during ADIM were reliable in this age group (ICC3,3 > 0.92). OI was always the thickest and TrA the thinnest muscle on both sides of the body. In this group, an identical pattern of the contribution of the individual muscles to the structure of the lateral abdominal wall (OI > OE > TrA) was observed. At rest and during ADIM, no statistically significant side-to-side differences were demonstrated in either gender. The body mass constitutes between 30% and <50% of the thickness differences in all muscles under examination at rest and during ADIM. The structure of lateral abdominal wall in adolescents is similar to that of adults. During ADIM, the abdominal muscles in adolescents react similarly to those in adults. This study provided extensive information regarding the structure of the lateral abdominal wall in healthy adolescents.

  14. Insertional action of the abdominal muscles in rabbits and dogs.

    PubMed

    D'Angelo, E; Prandi, E; Robatto, F; Petitjean, M; Bellemare, F

    1996-07-01

    The insertional action of the abdominal muscles was studied in supine anesthetized, apneic rabbits and dogs by comparing the changes in esophageal pressure (Pes), upper and lower rib cage circumference (Cru,u and Crc,I) and lung volume (VL) in response to electrical stimulation of all abdominal muscles before and after evisceration. In eviscerated animals, abdominal muscle contraction increased Pes and decreased both VL and Cre,I, but had no effect on Crc,u. Maximal responses were obtained at submaximal intensities of stimulation, and became larger with increasing lung volume. Relative to the vital capacity in intact animals, maximal delta VL for stimulation performed at FRC and TLC were 7.2 +/- 2.9(SD) and 39.5 +/- 7% in rabbits, and 6.3 +/- 0.8 and 18.3 +/- 5.9% in dogs, respectively. Relative to the changes in lung volume occurring with maximal contraction of the abdominal muscles in intact animals, the values of delta VL observed in the eviscerated animals amounted to approximately 35 and approximately 45% for stimulation performed at FRC and TLC, respectively. Hence, abdominal muscles exert substantial insertional action on the lower rib cage that can result in appreciable lung deflationary effects, particularly at elevated lung volumes.

  15. Influence of exercise training on the oxidative capacity of rat abdominal muscles

    NASA Technical Reports Server (NTRS)

    Uribe, J. M.; Stump, C. S.; Tipton, C. M.; Fregosi, R. F.

    1992-01-01

    Our purpose was to determine if endurance exercise training would increase the oxidative capacity of the abdominal expiratory muscles of the rat. Accordingly, 9 male rats were subjected to an endurance training protocol (1 h/day, 6 days/week, 9 weeks) and 9 litter-mates served as controls. Citrate synthase (CS) activity was used as an index of oxidative capacity, and was determined in the following muscles: soleus, plantaris, costal diaphragm, crural diaphragm, and in all four abdominal muscles: rectus abdominis, transversus abdominis, external oblique, and internal oblique. Compared to their non-trained litter-mates, the trained rats had higher peak whole body oxygen consumption rates (+ 16%) and CS activities in plantaris (+34%) and soleus (+36%) muscles. Thus, the training program caused substantial systemic and locomotor muscle adaptations. The CS activity of costal diaphragm was 20% greater in the trained animals, but no difference was observed in crural diaphragm. The CS activity in the abdominal muscles was less than one-half of that in locomotor and diaphragm muscles, and there were no significant changes with training except in the rectus abdominis where a 26% increase was observed. The increase in rectus abdominis CS activity may reflect its role in postural support and/or locomotion, as none of the primary expiratory pumping muscles adapted to the training protocol. The relatively low levels of CS activity in the abdominal muscles suggests that they are not recruited frequently at rest, and the lack of an increase with training indicates that these muscles do not contribute significantly to the increased ventilatory activity accompanying exercise in the rat.

  16. Control of abdominal muscles by brain stem respiratory neurons in the cat

    NASA Technical Reports Server (NTRS)

    Miller, Alan D.; Ezure, Kazuhisa; Suzuki, Ichiro

    1985-01-01

    The nature of the control of abdominal muscles by the brain stem respiratory neurons was investigated in decerebrate unanesthetized cats. First, it was determined which of the brain stem respiratory neurons project to the lumbar cord (from which the abdominal muscles receive part of their innervation), by stimulating the neurons monopolarly. In a second part of the study, it was determined if lumbar-projecting respiratory neurons make monosynaptic connections with abdominal motoneurons; in these experiments, discriminate spontaneous spikes of antidromically acivated expiratory (E) neurons were used to trigger activity from both L1 and L2 nerves. A large projection was observed from E neurons in the caudal ventral respiratory group to the contralateral upper lumber cord. However, cross-correlation experiments found only two (out of 47 neuron pairs tested) strong monosynaptic connections between brain stem neurons and abdominal motoneurons.

  17. Progressive Muscle Relaxation and Pain Perception in Abdominal Surgery Patients

    DTIC Science & Technology

    1989-05-01

    subjects (36%) had cholecystectomies, one subject (9%) had an appendectomy, one subject (9%) had a hysterectomy, four subjects (36%) had tubal ligations ...hysterectomies, three subjects (30%) had tubal ligations or fulgarations, five subjects (50%) had diagnostic laparoscopies, and one subject (10%) was classified...muscle relaxation could decrease pain perception, analgesic use, and anxiety in post -operative abdominal surgery patients. Review of demographic data

  18. Localization of motoneurons innervating individual abdominal muscles of the cat

    NASA Technical Reports Server (NTRS)

    Miller, Alan D.

    1987-01-01

    The paper presents the results of a systematic investigation of the innervation of the cat's individual abdominal muscles. The segmental distribution of the different motor pools was determined by using electrical microstimulation of the ventral horn to produce visible localized muscle twitches and by retrograde transport of horseradish peroxidase injected into individual muscles. The segmental distribution of each motor pool was as follows: rectus abdominis, T4-L3; external oblique, T6-L3; transverse abdominis, T9-L3; and internal oblique, T13-L3.

  19. Comparison of changes in the contraction of the lateral abdominal muscles between the abdominal drawing-in maneuver and breathe held at the maximum expiratory level.

    PubMed

    Ishida, Hiroshi; Hirose, Ryohei; Watanabe, Susumu

    2012-10-01

    The abdominal drawing-in maneuver (ADIM) is commonly used as a fundamental component of lumbar stabilization training programs. One potential limitation of lumbar stabilization programs is that it can be difficult and time consuming to train people to perform the ADIM. The transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles are the most powerful muscles involved in expiration. However, little is known about the differences in the recruitment of the abdominal muscles between the ADIM and breathe held at maximum expiratory level (maximum expiration). The thickness of the TrA and IO muscles was measured by ultrasound imaging, and the activity of the EO muscle was measured by electromyography (EMG) in 33 healthy male performing the ADIM and maximum expiration. Maximum expiration produced a significant increase in the thickness of the TrA and IO muscles compared to the ADIM (p < 0.001). The EMG activity of the EO muscle was significantly higher during maximum expiration than during the ADIM (p < 0.001). The intensity of the EMG activity of the EO muscle was approximately 30% of the maximal voluntary contraction during maximum expiration. Thus, maximum expiration may be an effective method for training of co-activation of the lateral abdominal muscles.

  20. Measurement the thickness of the transverse abdominal muscle in different tasks

    PubMed Central

    Pang, Ling; Yin, Liquan; Tajiri, Kimiko; Huo, Ming; Maruyama, Hitoshi

    2017-01-01

    [Purpose] This study examined the measurement of the thickness of the transverse abdominal muscle in different tasks. [Subjects and Methods] The subjects were eleven healthy adult females. Thicknesses of transverse abdominal muscle were measured in seven tasks in the supine position. The tasks were: 1) Resting state, 2) Maximal contraction of transverse abdominal muscle, 3) Maximal contraction of levator ani muscle, 4) Maximal simultaneous contraction of both transverse abdominal muscle and levator ani muscle, 5) Maximal simultaneous contraction of both transverse abdominal muscle and levator ani muscle with front side resistance added to both knee, 6) Maximal simultaneous contraction of both transverse abdominal muscle and levator ani muscle with diagonal resistance added to both knees, and 7) Maximal simultaneous contraction of both transverse abdominal muscle and levator ani muscle with lateral resistance added to both knees. [Results] The thicknesses of transverse abdominal muscle during maximal simultaneous contraction and maximal simultaneous contraction with resistance were greater than during the resting state. [Conclusion] The muscle output during simultaneous contraction and resistance movement were larger than that of each individual muscle. PMID:28265140

  1. Muscle activities during asymmetric trunk angular accelerations.

    PubMed

    Marras, W S; Mirka, G A

    1990-11-01

    The objective of this study was to characterize trunk muscle and intra-abdominal pressure behavior during extensions of the trunk when angular trunk acceleration levels and trunk twist were varied during lifting exertions. Since force is related to acceleration, it was believed that changes in trunk acceleration would cause activity changes in the muscles and abdominal cavity pressurization mechanics that load the spine during manual materials handling tasks. The electromyographic activity of 10 trunk muscles and intra-abdominal pressure were studied in 39 subjects as they moved their trunks under high, medium, and low constant angular acceleration conditions. The results indicated that almost all the muscles were affected by acceleration and asymmetry. Muscle activities of up to 50% of maximum were observed even though a minimal amount of torque was being produced by the back. Coactivation of muscles was also apparent. Muscles located at the greatest distances from the spine, such as the latissimus dorsi and oblique groups, increased their activities the most as trunk acceleration increased. Muscles located farthest from the spine also played an important role as the trunk became more asymmetric. Intra-abdominal pressure changed minimally over the test conditions. The nature of these responses and their impact on spine loading are discussed.

  2. Lumbo-pelvic stability and electromyography of abdominal muscles in ballet dancers.

    PubMed

    Negrão Filho, R de Faria; Silva, L Alves; Monteiro, T Lombardi; Alves, N; de Carvalho, A Cesinando; de Azevedo, F Mícolis

    2009-01-01

    Evaluating the ability to rectify and maintain lumbar adjustment can contribute toward the understanding of the behavior of abdominal muscles and their participation in the stability of pelvic muscles in dancers during the posterior pelvic tilt and double straight leg lowering tests. Nine healthy volunteers (male and female ballet dancers; age mean: 25.9 +/- 7.37 years) underwent maximal isometric voluntary contraction (MIVC), isometric voluntary contraction at 50% of MIVC, posterior pelvic tilt (PPT) and double straight leg lowering (DSLL) tests. The tests were carried out in a single day, with 3 repetitions each. During the tests, electromygraphic signals of the rectus abdominis, obliquus internus and obliquus externus were recorded. The signal acquisition system was made up of bipolar surface electrodes, electrogoniometer and an electromechanic device (pressure sensor), which were connected to a signal conditioner module. Root mean square values of each muscle during the DSLL and PPT were converted into percentage of activation of 50% MIVC. Lower back pressure was submitted to the same process. ANOVA with repeated measures was performed, with the level of significance set at p < 0.05. The results revealed that all dancers were able to maintain posterior pelvic tilt and there was trend toward greater activation of the bilateral obliquus internus muscle. In an attempt to keep the pelvic region stabilized during DSLL, there was a greater contribution from the obliquus externus muscle in relation to other abdominal muscles.

  3. The effect of food consumption on the thickness of abdominal muscles, employing ultrasound measurements.

    PubMed

    Kordi, Ramin; Rostami, Mohsen; Noormohammadpour, Pardis; Mansournia, Mohammad Ali

    2011-08-01

    Recently, the roles of transabdominal muscles particularly TrA (transverse abdominis) muscle in spinal stability leading to treatment of low back pain have been suggested. Both in clinical setting and follow up studies, abdominal muscle thickness measurements need to be repeated at a later point in time to demonstrate efficacy of a therapeutic intervention. Different issues have been suggested as source of error in the repeated measurements of abdominal muscle thickness in different days such as patient position and stability of probe location. The level of stomach fullness has not been investigated as a source of error in ultrasonic measurements of transabdominal muscles thickness. This study was performed to evaluate the effect of food consumption on thickness of lateral abdominal muscles. Lateral abdominal muscles thicknesses of 63 healthy volunteer men were measured before and after food consumption. All the measurements were performed in two transducer positions and both sides. Waist circumference and body weight of participants were also measured before and post-food consumption. The thickness measures of all three muscles layers of lateral abdominal muscles (external oblique, internal oblique and transversus abdominis) in both sides and measured positions were significantly reduced after food consumption. We found no correlation between the increase of waist circumference and reduction of muscle layer thicknesses after food consumption. In case of comparison between the values of transabdominal muscle thicknesses over the time, the effect of food consumption on muscle thickness might be assumed as a potential source of error.

  4. Innovative exercise device for the abdominal trunk muscles: An early validation study

    PubMed Central

    Murakami, Hideki; Inaki, Anri; Mochizuki, Takafumi; Demura, Satoru; Nakase, Junsuke; Yoshioka, Katsuhito; Yokogawa, Noriaki; Igarashi, Takashi; Takahashi, Naoki; Yonezawa, Noritaka; Kinuya, Seigo; Tsuchiya, Hiroyuki

    2017-01-01

    Background Exercise is one of the few treatments that provide significant improvements in chronic low back pain (CLBP). We developed an innovative exercise device for abdominal trunk muscles. This device can be used in a sitting or standing position and contains a built-in system to measure abdominal trunk muscle strength. We examined whether subjects can adequately use the device to perform the exercises and measure their abdominal trunk muscle strength. Methods We collected data on the body height, body weight, body mass index, and girth of 30 healthy male volunteers, and measured their grip power and trunk extensor muscle strength using a dynamometer. The volunteers performed a sit-up test as an indicator of trunk flexor muscle strength, and we measured their abdominal muscle strength using the device. We then evaluated the correlations between abdominal trunk muscle strength and anthropometric parameters as well as the strength of other muscles. In subsequent tests, 5 of the 30 subjects participated in two positron emission tomography (PET) series consisting of examinations after a resting period (control study) and during exercise (exercise study). For the exercise study, the subjects performed 2 sets of exercises for 20 minutes using the device before and after an injection of 18F-fluorodeoxyglucose (FDG). PET-computed tomography images were obtained 60 minutes after FDG injection in each study. We compared the skeletal muscle metabolism of the participants in both studies using the standardized uptake value. Results The muscle strength measured by the device and the 30-second sit-up frequency were correlated. FDG accumulation within the diaphragm and abdominal rectus muscles was significantly higher in the exercise study. Conclusion Our innovative exercise device facilitates a coordinated contraction of the abdominal trunk muscles at the anterior aspect and the roof of the core, and enables subjects to measure the strength of these muscles. PMID:28235060

  5. Effects of bridge exercises with a sling and vibrations on abdominal muscle thickness in healthy adults.

    PubMed

    Gong, Won-tae

    2015-01-01

    In the present study, we aimed to examine the changes in the thickness of the transversus abdominis (TrA) and internal oblique (Io) muscles using ultrasonography in adults who performed bridge exercises with the abdominal drawing-in maneuver and a sling and received micro vibrations. In total, 32 subjects were divided into a therapy (n= 16) and control (n= 16) groups. The therapy group completed nine sets, with four repetitions, of bridge exercises with the sling and received vibrations. The control group completed nine sets, with four repetitions, of bridge exercises with the sling and did not receive vibrations. The thicknesses of the TrA and Io muscles were measured in both groups using ultrasonography before and after therapy. According to the pressure applied to the biofeedback unit, both groups showed significant changes in the thicknesses of the TrA and Io muscles after therapy (P< 0.05). The change in the thickness of the TrA muscle after therapy was significantly different between the 2 groups when the pressures applied at 38, 42, and 46 mmHg (P< 0.05). Moreover, the change in the thickness of the Io muscle did not significantly different between the 2 groups at any of the pressures applied (P> 0.05). These findings indicate that approximately 15 minutes of vibrations during bridge exercises on unstable surfaces with a sling facilitates the activation of the deep trunk muscles and further enhances the activation of the TrA.

  6. Physical activity and abdominal obesity in youth.

    PubMed

    Kim, YoonMyung; Lee, SoJung

    2009-08-01

    Childhood obesity continues to escalate despite considerable efforts to reverse the current trends. Childhood obesity is a leading public health concern because overweight-obese youth suffer from comorbidities such as type 2 diabetes mellitus, nonalcoholic fatty liver disease, metabolic syndrome, and cardiovascular disease, conditions once considered limited to adults. This increasing prevalence of chronic health conditions in youth closely parallels the dramatic increase in obesity, in particular abdominal adiposity, in youth. Although mounting evidence in adults demonstrates the benefits of regular physical activity as a treatment strategy for abdominal obesity, the independent role of regular physical activity alone (e.g., without calorie restriction) on abdominal obesity, and in particular visceral fat, is largely unclear in youth. There is some evidence to suggest that, independent of sedentary activity levels (e.g., television watching or playing video games), engaging in higher-intensity physical activity is associated with a lower waist circumference and less visceral fat. Several randomized controlled studies have shown that aerobic types of exercise are protective against age-related increases in visceral adiposity in growing children and adolescents. However, evidence regarding the effect of resistance training alone as a strategy for the treatment of abdominal obesity is lacking and warrants further investigation.

  7. Role of the medial medullary reticular formation in relaying vestibular signals to the diaphragm and abdominal muscles

    NASA Technical Reports Server (NTRS)

    Mori, R. L.; Bergsman, A. E.; Holmes, M. J.; Yates, B. J.

    2001-01-01

    Changes in posture can affect the resting length of respiratory muscles, requiring alterations in the activity of these muscles if ventilation is to be unaffected. Recent studies have shown that the vestibular system contributes to altering respiratory muscle activity during movement and changes in posture. Furthermore, anatomical studies have demonstrated that many bulbospinal neurons in the medial medullary reticular formation (MRF) provide inputs to phrenic and abdominal motoneurons; because this region of the reticular formation receives substantial vestibular and other movement-related input, it seems likely that medial medullary reticulospinal neurons could adjust the activity of respiratory motoneurons during postural alterations. The objective of the present study was to determine whether functional lesions of the MRF affect inspiratory and expiratory muscle responses to activation of the vestibular system. Lidocaine or muscimol injections into the MRF produced a large increase in diaphragm and abdominal muscle responses to vestibular stimulation. These vestibulo-respiratory responses were eliminated following subsequent chemical blockade of descending pathways in the lateral medulla. However, inactivation of pathways coursing through the lateral medulla eliminated excitatory, but not inhibitory, components of vestibulo-respiratory responses. The simplest explanation for these data is that MRF neurons that receive input from the vestibular nuclei make inhibitory connections with diaphragm and abdominal motoneurons, whereas a pathway that courses laterally in the caudal medulla provides excitatory vestibular inputs to these motoneurons.

  8. Ultrasound measurement of deep abdominal muscle activity in sitting positions with different stability levels in subjects with and without chronic low back pain.

    PubMed

    Rasouli, Omid; Arab, Amir Massoud; Amiri, Mohsen; Jaberzadeh, Shapour

    2011-08-01

    The purpose of this study was to investigate the changes in the thickness of the transversus abdominis (TrA) and internal oblique (IO) muscles in three sitting postures with different levels of stability. The technique of ultrasound imaging was used for individuals with and without chronic low back pain (LBP). A sample of 40 people participated in this study. Subjects were categorised into two groups: with LBP (N = 20) and without LBP (N = 20). Changes in the thickness of tested muscles were normalized under three different sitting postures to actual muscle thickness at rest in the supine lying position and were expressed as a percentage of thickness change. The percentage of thickness change in TrA and IO increased as the stability of the sitting position decreased in both groups. However, the percentages of thickness change in all positions were less in subjects with LBP. There was a significant difference in thickness change in TrA when sitting on a gym ball between subjects with and without LBP but no difference was found when sitting on a chair. There was no significant difference in thickness change in IO in all positions between the two groups. Our findings indicate that difference in the percentage of thickness change in TrA between subjects with and without LBP increases as the stability of sitting position decreases.

  9. The effect of lumbar-pelvic alignment and abdominal muscle thickness on primary dysmenorrhea

    PubMed Central

    Kim, Moon-jeong; Baek, Il-hun; Goo, Bong-oh

    2016-01-01

    [Purpose] The purpose of this study was to identify effects of malalignment of the lumbar pelvis, as a passive element, and the thicknesses of abdominal muscles, as active elements, on primary dysmenorrhea. [Subjects and Methods] The subjects were divided into a primary dysmenorrhea group and normal group according to Visual Analogue Scale, and ultimately there were 28 subjects in the dysmenorrhea group and 22 subjects in the normal group. Alignment of the lumbar pelvis was measured by using a Formetric 4D analysis system, and the thicknesses of abdominal muscles were measured by using ultrasound imaging. [Result] Scoliosis was 6.7 ± 4.3° in the primary dysmenorrhea group and 3.8 ± 2.0° in the normal group, and the lordotic angles of the two groups were 0.6 ± 0.5° and 0.1 ± 0.3°, respectively. The thickness of the internal oblique was 3.8 ± 1.3 mm in the primary dysmenorrhea group and 6.0 ± 1.9 mm in the thicknesses of the transverse abdominis in the two groups were 2.6 ± 6.8 mm and 3.5 ± 6.1 mm, respectively. Furthermore, the thickness of the normal group, and the external oblique was 4.0 ± 0.8 mm in the primary dysmenorrhea group and 5.4 ± 1.4 mm in the normal group. [Conclusion] This study showed significant differences between the primary dysmenorrhea group and the normal group in lumbar-pelvic alignment and thicknesses of abdominal muscles. PMID:27821975

  10. In vivo ultrasound assessment of respiratory function of abdominal muscles in normal subjects.

    PubMed

    Misuri, G; Colagrande, S; Gorini, M; Iandelli, I; Mancini, M; Duranti, R; Scano, G

    1997-12-01

    Ultrasonography has recently been proposed for assessing changes in thickness and motion of the diaphragm during contraction in humans. Data on ultrasound assessment of abdominal muscles in humans are scarce. We therefore investigated the changes in thickness and the relevant mechanical effects of abdominal muscles using this technique during respiratory manoeuvres in normal subjects. We evaluated the thickness of the abdominal muscle layers in six normal male subjects (aged 26-36 yrs) using a 7.5 MHz B-mode ultrasound transducer. Gastric (Pg) and mouth pressures, muscle thickness of external oblique (EO), internal oblique (IO), transversus abdominis (TA) and rectus abdominis (RA) were assessed at functional residual capacity (FRC), residual volume (RV), total lung capacity (TLC), during progressive (PEEs) and maximal expiratory efforts (MEEs) against a closed airway and during homolateral (HTR) and contralateral (CTR) trunk rotation. Abdominal muscle thickness was found to be reproducible (coefficient of variation and two-way analysis of variance). Compared to FRC, the thickness of IO, TA and RA significantly increased at RV and during MEEs, whereas EO remained unchanged; at TLC, the thickness of IO and TA significantly decreased. During PEEs, a significant relationship between increase in Pg and TA thickness was observed in all subjects, the thickness of the other abdominal muscles being inconsistently related to Pg. Finally, a significant increase in the thickness of IO and EO was found during HTR and CTR, respectively. We conclude that during maximal expiratory manoeuvres, transversus abdominis, internal oblique and rectus abdominis thickened similarly. Transversus abdominis seems to be the major contributor in generating abdominal expiratory pressure during progressive expiratory efforts. External oblique seems to be preferentially involved during trunk rotation. These results suggest the possible value of studying the abdominal muscles by ultrasonography in

  11. Abdominal Closure after TRAM Flap Breast Reconstruction with Transversus Abdominis Muscle Release and Mesh

    PubMed Central

    Avendano-Peza, Héctor; Novitsky, Yuri W.

    2016-01-01

    Summary: Breast reconstruction with a pedicled transverse rectus abdominis muscle (TRAM) flap can result in significant abdominal wall donor-site morbidity. Although the pedicled TRAM flap donor area reinforced with mesh results in decreased rates of postoperative abdominal bulging and hernias, the best technique to accomplish that is yet to be elucidated. We present our novel technique of posterior components separation with transversus abdominis muscle release and retromuscular mesh reinforcement for donor-area closure during pedicled TRAM flap breast reconstruction. PMID:27757337

  12. Assessment of Abdominal Muscle's Maximal Force of Contraction Using Surface EMG in Inguinal Hernia Patients

    PubMed Central

    Sreenath, G. S.; Subramanian, Senthil Kumar

    2016-01-01

    Introduction Reduction in abdominal muscle’s strength has been implicated in the development of inguinal hernia. Patients with inguinal hernia on one side are shown to be at higher risk of developing inguinal hernia on the other side. Aim To assess the abdominal muscle strength in inguinal hernia subjects using surface Electromyography (EMG) and compare it with healthy controls. Materials and Methods This is a cross-sectional study involving only male subjects. Abdominal (Inguinal) hernia subjects without any known complications were recruited from surgery department and the accompanying healthy individuals were taken as control (Control, n=44, inguinal hernia subjects, n=43). The subjects were asked to perform maximal contraction for three seconds targeting external and internal oblique muscles of right and left sides separately. Motor unit potentials were recorded using surface EMG for individual muscles on both sides during maximal contraction. The maximum amplitude of the motor unit potentials obtained was considered as the strength of the respective muscle. Results In control group, there was no significant difference in strength of external and internal oblique muscles between the two sides. Strength of external and internal oblique muscles of both herniated and unaffected side was reduced in inguinal hernia subjects as compared to healthy controls. Further, the muscle strength of herniated side was less as compared to unaffected side in the inguinal hernia subjects. Conclusion Abdominal muscle strength is reduced in hernia subjects and even the apparently normal side strength is less as compared to controls. This should be considered while performing corrective surgeries in inguinal hernia subjects. PMID:28208924

  13. Rectus abdominis muscle resection and fascial reconstruction for the treatment of uterine leiomyosarcoma invading the abdominal wall: a case report.

    PubMed

    Yoon, B S; Seong, S J; Song, T; Kim, M L; Kim, M K

    2014-01-01

    The authors present a case of intra-abdominal recurrent leiomyosarcoma invading a large area of the abdominal wall. The patient underwent cytoreductive surgery, including resection of the rectus abdominis muscle, followed by reconstruction of the defect using synthetic mesh. The tumor was surgically removed by en bloc resection, including most of the rectus abdominis muscle and ileum. The abdominal wall defect was repaired using synthetic mesh. The patient underwent radiotherapy and chemotherapy after the surgery and was healthy one year later.

  14. Low-Grade Myxofibrosarcoma of the Rectus Abdominus Muscle Infiltrating into Abdominal Cavity: A Case Report

    PubMed Central

    Sakakibara, Shunsuke; Moriwaki, Aya; Kawamoto, Teruya; Suzuki, Satoshi; Ishimura, Takeshi; Hashikawa, Kazunobu; Terashi, Hiroto

    2017-01-01

    Objective: Myxofibrosarcoma (MFS) is a relatively rare tumor that is histologically characterized by myxoid stroma and spindle cell proliferation. This tumor most commonly arises as a slow growing, enlarging painless mass in the extremities of elderly patients. Methods: We report a case of a primary, low-grade MFS in the rectus abdominis muscle infiltrating the abdominal cavity of a 75-year-old man. Results: The patient underwent a wide excision of the right abdominal wall mass with a 3-cm surgical margin from the scar due to a biopsy. The tumor infiltrated the urinary bladder, peritoneum, and external iliac vessels. Twenty-six months after the initial operation, he had recurrences in his abdominal wall, urinary bladder, and right iliac vessels. Conclusions: To our knowledge, primary MFS of the muscle in the abdomen has not been documented previously. Although this case was histopathologically classified as a low-grade tumor, it infiltrated the abdominal cavity. The tumor is suspected to have penetrated the abdominal cavity below the linea arcuata, which lacks the posterior sheath of the rectus abdominis muscle; from there, it could easily spread without being blocked by any biological barriers. PMID:28293331

  15. Low-Grade Myxofibrosarcoma of the Rectus Abdominus Muscle Infiltrating into Abdominal Cavity: A Case Report.

    PubMed

    Nomura, Tadashi; Sakakibara, Shunsuke; Moriwaki, Aya; Kawamoto, Teruya; Suzuki, Satoshi; Ishimura, Takeshi; Hashikawa, Kazunobu; Terashi, Hiroto

    2017-01-01

    Objective: Myxofibrosarcoma (MFS) is a relatively rare tumor that is histologically characterized by myxoid stroma and spindle cell proliferation. This tumor most commonly arises as a slow growing, enlarging painless mass in the extremities of elderly patients. Methods: We report a case of a primary, low-grade MFS in the rectus abdominis muscle infiltrating the abdominal cavity of a 75-year-old man. Results: The patient underwent a wide excision of the right abdominal wall mass with a 3-cm surgical margin from the scar due to a biopsy. The tumor infiltrated the urinary bladder, peritoneum, and external iliac vessels. Twenty-six months after the initial operation, he had recurrences in his abdominal wall, urinary bladder, and right iliac vessels. Conclusions: To our knowledge, primary MFS of the muscle in the abdomen has not been documented previously. Although this case was histopathologically classified as a low-grade tumor, it infiltrated the abdominal cavity. The tumor is suspected to have penetrated the abdominal cavity below the linea arcuata, which lacks the posterior sheath of the rectus abdominis muscle; from there, it could easily spread without being blocked by any biological barriers.

  16. The effect of resistance exercise direction for hip joint stabilization on lateral abdominal muscle thickness

    PubMed Central

    Jung, Ju-Hyeon; Lee, Sang-Yeol

    2016-01-01

    The aim of this study was to determine the effects of resistance direction in hip joint stabilization exercise on change in lateral abdominal muscle thickness in healthy adults. Twenty-six healthy adults were randomly allocated to either a hip stabilization exercise by hip straight resistance group (n=12) or a hip diagonal resistance group (n=14). The outcome measures included contraction thickness ratio in transversus abdominis (TrA), internal oblique (IO) and external oblique, and TrA lateral slide were assessed during the abdominal drawing-in maneuver by b-mode ultrasound. The researcher measured the abdominal muscle thickness of each participant before the therapist began the intervention and at the moment intervention was applied. There was a significant difference in lateral abdominal muscle thickness between the straight resistance exercise of hip joint group and the diagonal resistance exercise of hip joint group. Significant differences were found between the two groups in the percentage of change of muscle thickness of the TrA (P=0.018) and in the thickness ratio of the TrA (P=0.018). Stability exercise accompanied by diagonal resistance on the hip joint that was applied in this study can induce automatic contraction of the IO and TrA, which provides stability to the lumbar spine. PMID:27807520

  17. The effects of deep abdominal muscle strengthening exercises on respiratory function and lumbar stability.

    PubMed

    Kim, Eunyoung; Lee, Hanyong

    2013-06-01

    [Purpose] The purpose of this study was to examine the effects of deep abdominal muscle strengthening exercises on respiratory function and lumbar stability. [Subjects] From among 120 male and female students, 22 whose thoraxes opened no more than 5 cm during inspiration and expiration and whose forced expiratory flow rates were around 300 m/L were recruited. The subjects were randomly divided into an experimental group of eleven, who performed deep abdominal muscle strengthening exercises, and a control group of eleven, who received no particular intervention. [Methods] The subjects were instructed to perform normal breathing in the hook-lying position. They were then directed to hold their breath for ten seconds at the end of inspiration. Ten repetitions of this breathing comprised a set of respiratory training, and a total of five sets were performed by the subjects. [Results] Deep abdominal muscle training was effective at enhancing respiratory function and lumbar stabilization. [Conclusion] The clinical application of deep abdominal muscle strengthening exercises along with lumbar stabilization exercises should be effective for lower back pain patients in need of lumbar stabilization.

  18. Active vs. inactive muscle (image)

    MedlinePlus

    ... may lose 20 to 40 percent of their muscle -- and, along with it, their strength -- as they ... have found that a major reason people lose muscle is because they stop doing everyday activities that ...

  19. Contractile properties of the rat external abdominal oblique and diaphragm muscles during development.

    PubMed

    Watchko, J F; Brozanski, B S; O'Day, T L; Guthrie, R D; Sieck, G C

    1992-04-01

    We studied the in vitro contractile and fatigue properties of the rat external abdominal oblique (EAO) and costal diaphragm (DIA) muscles during postnatal development. Isometric twitch contraction (CT) and half-relaxation (RT1/2) times were longer in both the EAO and DIA muscles during the early postnatal period and decreased with age. In the first postnatal week, the CT and RT1/2 were longer in the EAO than the DIA muscle. At 14 days of age and thereafter, the CT and RT1/2 were shorter in the EAO than in the DIA muscle. Force-frequency relationships of the EAO and DIA muscles changed during postnatal development such that the relative force (percent maximum) generated at lower frequencies (less than 15 pulses/s) decreased with age. Moreover the relative force generated by the EAO muscle at lower frequencies was greater than that of the DIA muscle during the early postnatal period but less than that of the DIA muscle in adults. The specific force of both the EAO and DIA muscles increased progressively with age. There were no differences in specific force between the EAO and DIA muscles at any age. The fatigability of the EAO and DIA muscles was comparable during the early postnatal period and increased in both muscles with postnatal development. In adults the EAO muscle was more fatigable than the DIA muscle. We conclude that the contractile and fatigue properties of the EAO and DIA muscles undergo significantly different postnatal transitions, which may reflect their functional involvement in sustaining ventilation.

  20. Trunk response to sudden forward perturbations - effects of preload and sudden load magnitudes, posture and abdominal antagonistic activation.

    PubMed

    Shahvarpour, Ali; Shirazi-Adl, Aboulfazl; Mecheri, Hakim; Larivière, Christian

    2014-06-01

    Unexpected loading of the spine is a risk factor for low back pain. The trunk neuromuscular and kinematics responses are likely influenced by the perturbation itself as well as initial trunk conditions. The effect of four parameters (preload, sudden load, initial trunk flexed posture, initial abdominal antagonistic activity) on trunk kinematics and back muscles reflex response were evaluated. Twelve asymptomatic subjects participated in sudden forward perturbation tests under six distinct conditions. Preload did not change the reflexive response of back muscles and the trunk displacement; while peak trunk velocity and acceleration as well as the relative load peak decreased. Sudden load increased reflex response of muscles, trunk kinematics and loading variables. When the trunk was initially flexed, back muscles latency was delayed, trunk velocity and acceleration increased; however, reflex amplitude and relative trunk displacement remained unchanged. Abdominal antagonistic preactivation increased reflexive response of muscles but kinematics variables were not affected. Preload, initial flexed posture and abdominal muscles preactivation increased back muscles preactivity. Both velocity and acceleration peaks of the trunk movement decreased with preload despite greater total load. In contrast, they increased in the initial flexed posture and to some extent when abdominal muscles were preactivated demonstrating the distinct effects of pre-perturbation variables on trunk kinematics and risk of injury.

  1. Ultrasound evaluation of the symmetry of abdominal muscles in mild adolescent idiopathic scoliosis

    PubMed Central

    Linek, Paweł; Saulicz, Edward; Wolny, Tomasz; Myśliwiec, Andrzej; Gogola, Anna

    2015-01-01

    [Purpose] The objective of the study was to evaluate the symmetry of the thickness of the abdominal muscles at rest and while standing in patients with adolescent idiopathic scoliosis. [Subjects and Methods] An ultrasound assessment was performed of the side-to-side differences of the external oblique (EO), internal oblique (IO), and transversus abdominalis (TrA) muscles in the supine and standing positions in adolescent idiopathic scoliosis (AIS) and control groups. [Results] In the AIS group, 64.3% of the patients had left scoliosis with a mean Cobb angle of 10.7°, and 35.7% of the patients had right scoliosis with a mean Cobb angle of 10°. In the supine position, the thickness asymmetry of the TrA was greater in the AIS compared with the control group by an average of 14% (95% CI 3.9–24.2). [Conclusion] Among the abdominal muscles examined, patients with AIS exhibited more asymmetry only for the TrA. In the standing position, the TrA was as symmetric in the patients as in the control group. Mild scoliosis has no impact on the symmetry of the thickness of the OE and OI in the supine and standing positions. The direction of curvature had no effect on the symmetry of the abdominal muscles studied. PMID:25729192

  2. Short-term effect of crunch exercise frequency on abdominal muscle endurance.

    PubMed

    Juan-Recio, C; López-Vivancos, A; Moya, M; Sarabia, J M; Vera-Garcia, F J

    2015-04-01

    Despite core exercise programs are broadly used to increase muscle function and to promote low back health, there is a lack of scientific evidence on some of the most important characteristics of trunk exercise programs, as for example training frequency. This study aimed to compare the short-term effect of training frequencies of 1, 2 and 3 days per week (d/wk) on abdominal muscle endurance in untrained adolescents. One hundred and eighteen high-school students (59 men and 59 women) with no previous experience in structured abdominal exercise programs were assigned randomly to groups that trained 1 d/wk (G1; N.=21), 2 d/wk (G2; N.=27), 3 d/wk (G3; N.=23), or to a control group (CG; N.=47) that did not train. The training groups performed crunch and cross-crunch exercises 1, 2 or 3 d/wk during six weeks. Before and after the training period, the bench trunk-curl test (BTC test) was carried out to assess abdominal muscle endurance. Men obtained higher BTC test scores than women before and after training. Training frequencies of 1, 2 and 3 d/wk provided a significant increase in BTC test scores; however, no significant differences between the three groups' scores were found after training. Therefore, a small dose of crunch exercise training (1 d/wk) may be sufficient stimulus to increase abdominal endurance in untrained male and female adolescents, at least during the first weeks of an abdominal exercise program, which seems a very relevant finding in terms of time-cost efficiency.

  3. Lung-deflating ability of rib cage and abdominal muscles in rabbits.

    PubMed

    D'Angelo, Edgardo; Prandi, Edi; D'Angelo, Emanuela; Pecchiari, Matteo

    2003-04-15

    Anesthetized, apneic, mechanically ventilated rabbits were placed into a tilting plethysmograph that a rubber diaphragm, tightly fitting the animal's body just below the xiphoid process, separated into a rib cage and abdominal chamber. Expired volumes (DeltaV) and abdominal pressure changes (DeltaPab) were assessed in supine and upright posture during maximal rib cage (RCC) and/or abdominal compression (ABC) by pressurizing either or both chambers, and during maximal stimulations of abdominal muscles (ABS). With RCC, DeltaV supine and upright amounted to 16+/-4.9 (mean+/-S.D.) and 20.9+/-7% of the vital capacity in supine posture (VCs) and to 75.8+/-14.5 and 44.8+/-13.9% of the expiratory reserve volume (ERV) in corresponding posture, DeltaPab being negligible. With ABC, DeltaV was 13.7+/-2 and 38.9+/-7.3% VCs and 68.4+/-14.8 and 84.4+/-10.5% ERV, respectively. Both DeltaV and DeltaPab were similar with ABC and ABS, independent of posture. If this applies also to RCC and expiratory rib cage muscle contraction, maximal expiratory effects of the latter (a) are larger in upright than supine posture; (b) contribute to ERV more in supine than upright posture; and (c) are similar to those caused by ABS in supine, but substantially smaller in upright posture.

  4. MALDI imaging mass spectrometry of Pacific White Shrimp L. vannamei and identification of abdominal muscle proteins.

    PubMed

    Schey, Kevin L; Hachey, Amanda J; Rose, Kristie L; Grey, Angus C

    2016-06-01

    MALDI imaging mass spectrometry (IMS) has been applied to whole animal tissue sections of Pacific White Shrimp, Litopenaeus vannamei, in an effort to identify and spatially localize proteins in specific organ systems. Frozen shrimp were sectioned along the ventral-dorsal axis and methods were optimized for matrix application. In addition, tissue microextraction and homogenization was conducted followed by top-down LC-MS/MS analysis of intact proteins and searches of shrimp EST databases to identify imaged proteins. IMS images revealed organ system specific protein signals that highlighted the hepatopancreas, heart, nervous system, musculature, and cuticle. Top-down proteomics identification of abdominal muscle proteins revealed the sequence of the most abundant muscle protein that has no sequence homology to known proteins. Additional identifications of abdominal muscle proteins included titin, troponin-I, ubiquitin, as well as intact and multiple truncated forms of flightin; a protein known to function in high frequency contraction of insect wing muscles. The combined use of imaging mass spectrometry and top-down proteomics allowed for identification of novel proteins from the sparsely populated shrimp protein databases.

  5. Postnatal expression of myosin isoforms in an expiratory muscle--external abdominal oblique.

    PubMed

    Watchko, J F; Daood, M J; Vazquez, R L; Brozanski, B S; LaFramboise, W A; Guthrie, R D; Sieck, G C

    1992-11-01

    We studied the postnatal expression of heavy-chain (MHC) and native myosin isoforms in an expiratory abdominal muscle of the rat, the external abdominal oblique (EO). Moreover, we contrasted EO myosin expression with that of the costal diaphragm (DIA) to draw inspiratory vs. expiratory muscle comparisons during development. Examination of MHC gels demonstrated a mature phenotype of slow and adult fast myosin isoforms at an earlier age in the EO (day 60) than in the DIA [day > 115 (adult)]. The mature MHC phenotype of the EO was characterized by a preponderance of MHC 2B, whereas the DIA was characterized by approximately equal portions of MHC slow, MHC 2A, and MHC 2X. During early postnatal development, there was a delay in the expression of MHC 2A in the EO compared with the DIA. However, MHC 2B, expressed later in development in both muscles, was noted in the EO before the DIA. We conclude that 1) the EO mature myosin phenotype is characterized by a preponderance of fast myosin isoforms and 2) the EO and DIA muscles are subject to different temporal patterns of isoform expression during postnatal development.

  6. [Study of diaphragmatic muscle function during abdominal weight in normal subjects].

    PubMed

    Monteiro, Sergio G; Pessolano, Fernando A; Suárez, Adrián A; De Vito, Eduardo L

    2012-01-01

    The effects of the abdominal weight with the intention of producing training of the diaphragm, have not been sufficiently evaluated. We studied the function of the diaphragm during the abdominal weight training and during associated changes in the respiratory pattern. Six normal volunteers were studied. Flow at the mouth at functional residual capacity (FRC) was obtained as well as gastric pressure (Pga), esophageal pressure (Pes), thoracic and abdominal movements, maximal inspiratory pressure and mean and maximal transdiaphragmatic pressure (Pdi and Pdi max). Pdi/Pdimax and the diaphragm tension-time index (TTdi) were calculated. Studied steps: normal pattern (NP), abdominal pattern (AP) and weight of 1, 2, 4 and 6 kg with NP and AP as well. We found 1) The AP was facilitated by the abdominal weight, 2) Only with 6 kg (NP and AP) the Pga at FRC increased significantly (p 0.001), 3) the Pdi followed the variations of the Pga and increased with all the AP (p < 0.001), 4) The index TTdi load reached a value of 0.05 ± 0.02 (p < 0.001). The charges did not increase this rate more than did the AP alone. Our findings suggest abdominal weight increases propioception related to the respiratory movements and descent of the diaphragm. The loads on the abdomen produce minor changes in mechanics of the diaphragm (1/3 of the load required to develop fatigue in normal subjects). Al least in normal subjects these changes appear to be insufficient to produce respiratory muscle training.

  7. Training through gametherapy promotes coactivation of the pelvic floor and abdominal muscles in young women, nulliparous and continents

    PubMed Central

    Silva, Valeria Regina; Riccetto, Cássio; Martinho, Natalia Miguel; Marques, Joseane; Carvalho, Leonardo Cesar; Botelho, Simone

    2016-01-01

    ABSTRACT Introduction and objectives: Several studies have been investigated co-activation can enhance the effectveness of PFM training protocols allowing preventive and therapeutic goals in pelvic floor dysfunctions. The objective of the present study was to investigate if an abdominal-pelvic protocol of training (APT) using gametherapy would allow co-activation of PFM and transversus abdominis/oblique internal (TrA/OI) muscles. Patients and methods: Twenty-five nulliparous, continent, young females, with median age 24.76 (±3.76) years were evaluated using digital palpation (DP) of PFM and surface electromyography of PFM and TrA/OI simultaneously, during maximal voluntary contraction (MVC), alternating PFM and TrA/OI contraction requests. All women participated on a supervised program of APT using gametherapy, that included exercises of pelvic mobilization associated to contraction of TrA/OI muscles oriented by virtual games, for 30 minutes, three times a week, in a total of 10 sessions. Electromyographic data were processed and analyzed by ANOVA - analysis of variance. Results: When MVC of TrA/OI was solicited, it was observed simultaneous increase of electromyographic activity of PFM (p=0.001) following ATP. However, EMG activity did not change significantly during MVC of PFM. Conclusion: Training using gametherapy allowed better co-activation of pelvic floor muscles in response to contraction of TrA, in young nulliparous and continent women. PMID:27564290

  8. Abdominal lean muscle is associated with lower mortality among kidney waitlist candidates.

    PubMed

    Locke, Jayme E; Carr, J Jeffrey; Nair, Sangeeta; Terry, James G; Reed, Rhiannon D; Smith, Grant D; Segev, Dorry L; Kumar, Vineeta; Lewis, Cora E

    2017-03-01

    Morphometric assessments, such as muscle density and body fat distribution, have emerged as strong predictors of cardiovascular risk and postoperative morbidity and mortality. To date, no study has examined morphometric mortality risk prediction among kidney transplant (KT) candidates. KT candidates, waitlisted 2008-2009, were identified (n=96) and followed to the earliest of transplant, death, or administrative end of study. Morphometric measures, including abdominal adipose tissue, paraspinous and psoas muscle composition, and aortic calcification, were measured from CTs. Risk of waitlist mortality was examined using Cox proportional hazard regression. On adjusted analyses, radiologic measures remained independently and significantly associated with lower waitlist mortality; the addition of radiologic measures significantly improved model predictive ability over models containing traditional risk factors alone (net reclassification index: 0.56, 95% CI: 0.31-0.75). Higher psoas muscle attenuation (indicative of leaner muscle) was associated with decreased risk of death (aHR: 0.93, 95% CI: 0.91-0.96, P<.001), and for each unit increase in lean paraspinous volume, there was an associated 2% decreased risk for death (aHR: 0.98, 95% CI: 0.96-0.99, P=.03). Radiologic measures of lean muscle mass, such as psoas muscle attenuation and paraspinous lean volume, may improve waitlist mortality risk prediction and candidate selection.

  9. Pravastatin activates activator protein 2 alpha to argument the angiotensin II-induced abdominal aortic aneurysms.

    PubMed

    Ma, Hui; Liang, Wen-Jing; Shan, Mei-Rong; Wang, Xue-Qing; Zhou, Sheng-Nan; Chen, Yuan; Guo, Tao; Li, Peng; Yu, Hai-Ya; Liu, Chao; Yin, Ya-Ling; Wang, Yu-Lin; Dong, Bo; Pang, Xin-Yan; Wang, Shuang-Xi

    2017-02-04

    We have previously reported that activation of AMP-activated kinase alpha 2 (AMPKα2) by nicotine or angiotensin II (AngII) instigates formation of abdominal aortic aneurysms (AAA) in Apoe-/- mice. Statins, used to treat hyperlipidemia widely, activate AMPK in vascular cells. We sought to examine the effects of pravastatin on AAA formation and uncover the molecular mechanism. The AAA model was induced by AngII and evaluated by incidence, elastin degradation, and maximal abdominal aortic diameter in Apoe-/- mice. The phosphorylated levels of AMPKα2 and activator protein 2 alpha (AP-2α) were examined in cultured vascular smooth muscle cells (VSMCs) or in mice. We observed that pravastatin (50 mg/kg/day, 8 weeks) remarkably increased the AngII-induced AAA incidence in mice. In VSMCs, pravastatin increased the levels of pAMPK, pAP-2α, and MMP2 in both basal and AngII-stressed conditions, which were abolished by tempol and compound C. Pravastatin-upregulated MMP2 was abrogated by AMPKα2 or AP-2α siRNA. Lentivirus-mediated gene silence of AMPKα2 or AP-2α abolished pravastatin-worsened AAA formations in AngII-infused Apoe-/- mice. Clinical investigations demonstrated that both AMPKα2 and AP-2α phosphorylations were increased in AAA patients or human subjects taking pravastatin. In conclusion, pravastatin promotes AAA formation through AMPKα2-dependent AP-2α activations.

  10. Reconstruction of Abdominal Wall Defects Using a Pedicled Anterolateral Thigh Flap including the Vastus Lateralis Muscle: A Report of Two Cases

    PubMed Central

    Fujioka, Masaki; Ishiyama, Satoko

    2016-01-01

    The purpose of abdominal wall reconstruction is to prevent hernias and protect the abdominal viscera. In cases involving full-thickness defects of the rectus abdominis muscle, the muscle layer should be repaired. We present 2 cases in which full-thickness lower rectus abdominis muscle defects were reconstructed using vastus lateralis-anterolateral thigh flaps. The pedicled vastus lateralis-anterolateral thigh flap provides skin, fascia, and muscle tissue. Furthermore, it has a long neurovascular pedicle and can reach up to the periumbilical area and cover large defects. We consider that this muscle flap is a good option for repairing full-thickness lower abdominal defects. PMID:28074168

  11. A Case of Pulmonary Paragonimiasis with Involvement of the Abdominal Muscle in a 9-Year-Old Girl

    PubMed Central

    Cho, Ah-Rum; Lee, Hae-Ran; Lee, Kwan-Sub; Lee, Sang-Eun

    2011-01-01

    In Korea, many people enjoy eating raw or underkooked freshwater crayfish and crabs which unfortunately may cause paragonimiasis. Here, we describe a case of pulmonary and abdominal paragonimiasis in a 9-year-old girl, who presented with a 1-month history of abdominal pain, especially in the right flank and the right inguinal area, with anorexia. A chest radiograph revealed pleural effusion in both lungs, and her abdominal sonography indicated an inflammatory lesion in the right psoas muscle. Peripheral blood analysis of the patient showed hypereosinophilia (66.0%) and an elevated total serum IgE level (>2,500 IU/ml). The pleural effusion tested by ELISA were also positive for antibodies against paragonimiasis. Her dietary history stated that she had ingested raw freshwater crab, 4 months previously. The diagnosis was pulmonary paragonimiasis accompanied by abdominal muscle involvement. She was improved after 5 cycles of praziquantel treatment and 2 times of pleural effusion drainage. In conclusion, herein, we report a case of pulmonary and abdominal paragonimiasis in a girl who presented with abdominal pain and tenderness in the inguinal area. PMID:22355209

  12. Genome-Wide Association Study for Muscle Fat Content and Abdominal Fat Traits in Common Carp (Cyprinus carpio)

    PubMed Central

    Zheng, Xianhu; Kuang, Youyi; Lv, Weihua; Cao, Dingchen; Sun, Zhipeng; Sun, Xiaowen

    2016-01-01

    Muscle fat content is an important phenotypic trait in fish, as it affects the nutritional, technical and sensory qualities of flesh. To identify loci and candidate genes associated with muscle fat content and abdominal fat traits, we performed a genome-wide association study (GWAS) using the common carp 250 K SNP assay in a common carp F2 resource population. A total of 18 loci surpassing the genome-wide suggestive significance level were detected for 4 traits: fat content in dorsal muscle (MFdo), fat content in abdominal muscle (MFab), abdominal fat weight (AbFW), and AbFW as a percentage of eviscerated weight (AbFP). Among them, one SNP (carp089419) affecting both AbFW and AbFP reached the genome-wide significance level. Ten of those loci were harbored in or near known genes. Furthermore, relative expressions of 5 genes related to MFdo were compared using dorsal muscle samples with high and low phenotypic values. The results showed that 4 genes were differentially expressed between the high and low phenotypic groups. These genes are, therefore, prospective candidate genes for muscle fat content: ankyrin repeat domain 10a (ankrd10a), tetratricopeptide repeat, ankyrin repeat and coiled-coil containing 2 (tanc2), and four jointed box 1 (fjx1) and choline kinase alpha (chka). These results offer valuable insights into the complex genetic basis of fat metabolism and deposition. PMID:28030623

  13. Genome-Wide Association Study for Muscle Fat Content and Abdominal Fat Traits in Common Carp (Cyprinus carpio).

    PubMed

    Zheng, Xianhu; Kuang, Youyi; Lv, Weihua; Cao, Dingchen; Sun, Zhipeng; Sun, Xiaowen

    2016-01-01

    Muscle fat content is an important phenotypic trait in fish, as it affects the nutritional, technical and sensory qualities of flesh. To identify loci and candidate genes associated with muscle fat content and abdominal fat traits, we performed a genome-wide association study (GWAS) using the common carp 250 K SNP assay in a common carp F2 resource population. A total of 18 loci surpassing the genome-wide suggestive significance level were detected for 4 traits: fat content in dorsal muscle (MFdo), fat content in abdominal muscle (MFab), abdominal fat weight (AbFW), and AbFW as a percentage of eviscerated weight (AbFP). Among them, one SNP (carp089419) affecting both AbFW and AbFP reached the genome-wide significance level. Ten of those loci were harbored in or near known genes. Furthermore, relative expressions of 5 genes related to MFdo were compared using dorsal muscle samples with high and low phenotypic values. The results showed that 4 genes were differentially expressed between the high and low phenotypic groups. These genes are, therefore, prospective candidate genes for muscle fat content: ankyrin repeat domain 10a (ankrd10a), tetratricopeptide repeat, ankyrin repeat and coiled-coil containing 2 (tanc2), and four jointed box 1 (fjx1) and choline kinase alpha (chka). These results offer valuable insights into the complex genetic basis of fat metabolism and deposition.

  14. The Effects of Horse Riding Simulation Training on Stroke Patients’ Balance Ability and Abdominal Muscle Thickness Changes

    PubMed Central

    Baek, Il-Hun; Kim, Byeong Jo

    2014-01-01

    [Purpose] The purpose of this study was to assess the effects of horse riding simulation training on changes in balance ability and abdominal muscle thicknesses of stroke patients. [Subjects] Thirty stroke patients with hemiplegia were recruited, and they were randomly assigned to a control or experimental group. [Methods] The experimental group performed horse riding simulation training, whereas the control group performed trunk exercises for 8 weeks. Balance ability was measured using a BioRescue system. The thicknesses of subjects’ external oblique, internal oblique, and transversus abdominis muscles were measured by ultrasonic imaging. [Results] In the experimental group, balance ability was significantly improved after training. Similarly, the thickness of the abdominal muscles on the affected side changed after training in the experimental group, whereas the control group showed no statistically significant changes. [Conclusion] We suggest that horse riding simulation training is more effective than trunk exercises at reducing the center of pressure path length and travel speed and improving the asymmetry of the abdominal muscles of stroke patients. PMID:25202200

  15. The Activity of Surface Electromyographic Signal of Selected Muscles during Classic Rehabilitation Exercise

    PubMed Central

    Xiao, Jinzhuang; Sun, Jinli; Gao, Junmin; Wang, Hongrui; Yang, Xincai

    2016-01-01

    Objectives. Prone bridge, unilateral bridge, supine bridge, and bird-dog are classic rehabilitation exercises, which have been advocated as effective ways to improve core stability among healthy individuals and patients with low back pain. The aim of this study was to investigate the activity of seven selected muscles during rehabilitation exercises through the signal of surface electromyographic. Approaches. We measured the surface electromyographic signals of four lower limb muscles, two abdominal muscles, and one back muscle during rehabilitation exercises of 30 healthy students and then analyzed its activity level using the median frequency method. Results. Different levels of muscle activity during the four rehabilitation exercises were observed. The prone bridge and unilateral bridge caused the greatest muscle fatigue; however, the supine bridge generated the lowest muscle activity. There was no significant difference (P > 0.05) between left and right body side muscles in the median frequency slope during the four rehabilitation exercises of seven muscles. Conclusions. The prone bridge can affect the low back and lower limb muscles of most people. The unilateral bridge was found to stimulate muscles much more active than the supine bridge. The bird-dog does not cause much fatigue to muscles but can make most selected muscles active. PMID:27195151

  16. The Activity of Surface Electromyographic Signal of Selected Muscles during Classic Rehabilitation Exercise.

    PubMed

    Xiao, Jinzhuang; Sun, Jinli; Gao, Junmin; Wang, Hongrui; Yang, Xincai

    2016-01-01

    Objectives. Prone bridge, unilateral bridge, supine bridge, and bird-dog are classic rehabilitation exercises, which have been advocated as effective ways to improve core stability among healthy individuals and patients with low back pain. The aim of this study was to investigate the activity of seven selected muscles during rehabilitation exercises through the signal of surface electromyographic. Approaches. We measured the surface electromyographic signals of four lower limb muscles, two abdominal muscles, and one back muscle during rehabilitation exercises of 30 healthy students and then analyzed its activity level using the median frequency method. Results. Different levels of muscle activity during the four rehabilitation exercises were observed. The prone bridge and unilateral bridge caused the greatest muscle fatigue; however, the supine bridge generated the lowest muscle activity. There was no significant difference (P > 0.05) between left and right body side muscles in the median frequency slope during the four rehabilitation exercises of seven muscles. Conclusions. The prone bridge can affect the low back and lower limb muscles of most people. The unilateral bridge was found to stimulate muscles much more active than the supine bridge. The bird-dog does not cause much fatigue to muscles but can make most selected muscles active.

  17. Complement activation promotes muscle inflammation during modified muscle use

    NASA Technical Reports Server (NTRS)

    Frenette, J.; Cai, B.; Tidball, J. G.

    2000-01-01

    Modified muscle use can result in muscle inflammation that is triggered by unidentified events. In the present investigation, we tested whether the activation of the complement system is a component of muscle inflammation that results from changes in muscle loading. Modified rat hindlimb muscle loading was achieved by removing weight-bearing from the hindlimbs for 10 days followed by reloading through normal ambulation. Experimental animals were injected with the recombinant, soluble complement receptor sCR1 to inhibit complement activation. Assays for complement C4 or factor B in sera showed that sCR1 produced large reductions in the capacity for activation of the complement system through both the classical and alternative pathways. Analysis of complement C4 concentration in serum in untreated animals showed that the classical pathway was activated during the first 2 hours of reloading. Analysis of factor B concentration in untreated animals showed activation of the alternative pathway at 6 hours of reloading. Administration of sCR1 significantly attenuated the invasion of neutrophils (-49%) and ED1(+) macrophages (-52%) that occurred in nontreated animals after 6 hours of reloading. The presence of sCR1 also reduced significantly the degree of edema by 22% as compared to untreated animals. Together, these data show that increased muscle loading activated the complement system which then briefly contributes to the early recruitment of inflammatory cells during modified muscle loading.

  18. Comparison of Lateral Abdominal Muscle Thickness and Cross Sectional Area of Multifidus in Adolescent Soccer Players with and without Low Back Pain: A Case Control Study

    PubMed Central

    Noormohammadpour, Pardis; Hosseini Khezri, Alireza; Linek, Paweł; Mansournia, Mohammad Ali; Hassannejad, Alireza; Younesian, Ali; Farahbakhsh, Farzin; Kordi, Ramin

    2016-01-01

    Background Low back pain (LBP) is a common complaint amongst adolescent athletes. While different studies have shown association between LBP and trunk muscle thickness in the general population, few articles have studied it in adolescent athletes. Objectives The aim of this study is to compare lateral abdominal muscle thickness and function, and cross sectional area (CSA) of lumbar multifidus (LM) in adolescent soccer players with and without LBP. Methods In total, 28 adolescent soccer players with and without LBP, from the premier league participated in this study. The thickness of external oblique, internal oblique and transversus abdominis and the CSA of the LM muscles at L4 level on both sides were measured at rest and contraction via ultrasound imaging (USI). In addition, leg length discrepancy, hamstring flexibility, active lumbar forward flexion, and isometric muscle endurance of trunk extensors were measured in both groups. (study design/setting: case control study). Results The mean (SD) age in LBP group and non-LBP group were 14.0 (1.1) and 14.1 (0.9) years, respectively. There was no significant difference in baseline characteristics of participants between groups. Findings showed no significant difference between LBP and non-LBP groups comparing all measured variables. Conclusions The data obtained support that there is not a correlation between abdominal muscle thickness and CSA of the lumbar multifidi and LBP in adolescent soccer players. These findings suggest that other factors rather than the thickness of deep trunk muscles may play a more significant role in the etiology of LBP in adolescent soccer players. PMID:28144414

  19. Long-term overactivity in the abdominal oblique muscles after 8 weeks bed-rest- possible implications for musculosketletal health

    NASA Astrophysics Data System (ADS)

    Belavy, D. L.; Richardson, C. A.; Wilson, S.; Darnell, R.; Hides, J.; Toppenberg, R.; Elmann-Larsen, B.; Rittweger, J.; Felsenberg, D.

    2005-08-01

    Changes in the human lumbo-pelvic (LP) muscles with unloading has received little attention in microgravity research, even though this body region has evolved with the development of upright posture in 1-g. This study used a specific movement task to examine the function of four LP muscles during 8-weeks of bed-rest and one-year follow-up. The main finding was the development of overactivity in the abdominal internal oblique muscle in the follow-up period. This finding implies that the L-P muscle changes occurring during bedrest do not recover on return to the 1-g environment. These results may have implications for musculo-skeletal health for those in sedentary lifestyles on Earth.

  20. Dynamic reconstruction of full-thickness abdominal wall defects using free innervated vastus lateralis muscle flap combined with free anterolateral thigh flap.

    PubMed

    Iida, Takuya; Mihara, Makoto; Narushima, Mitsunaga; Todokoro, Takeshi; Hara, Hisako; Yoshimatu, Hidehiko; Koshima, Isao; Kadono, Takafumi

    2013-03-01

    Reconstruction of full-thickness abdominal wall defects remains a difficult surgical challenge. Although various reconstructive methods, including artificial mesh, pedicled and free flaps, have been reported, most reported reconstruction of only the fascia layer, leaving the resected rectus abdominis muscle unreconstructed. However, recent studies suggested the importance of dynamic reconstruction with functional muscle in preventing abdominal hernia in the long-term. According to the principle of reconstructive surgery, "replace lost tissue with similar tissue," a functionally and aesthetically ideal reconstruction is to reconstruct all components of the abdominal wall structure, including skin, subcutaneous fat, fascia, and muscle. We present 2 cases with full-thickness abdominal wall defects in the upper abdominal region, which we reconstructed with a free innervated vastus lateralis muscle flap combined with a free anterolateral thigh flap. The motor nerve of the vastus lateralis muscle was sutured with the intercostal nerve, and reinnervation was confirmed by electromyography. This method allows reconstruction of all components of the abdominal wall with a single flap, and dynamic reconstruction is achieved which will reduce the risk of postoperative hernia. We believe this method can be a good option for reconstruction of full-thickness abdominal wall defects with long-term stability.

  1. Airflow synchronous with oscillatory acceleration reflects involuntary respiratory muscle activity.

    PubMed

    Brown, Richard E; Lee, Hsueh-Tze; Loring, Stephen H

    2004-06-25

    To explore mechanisms causing involuntary airflow synchronous with oscillatory axial whole body acceleration (oscillatory axial acceleration, OAA) such as that during locomotion, we monitored airflow, acceleration, and electromyograms (EMGs) of the rib cage and abdominal muscles in standing subjects undergoing OAA at 3, 6, and 9 Hz at accelerations of 0.1-0.95 g. Subjects relaxed or performed static respiratory maneuvers at constant lung volume with glottis open. Oscillatory airflows (0.01-3.01 s(-1)) synchronous with OAA were not consistent with expectations for a passive respiratory system, and were larger during active respiratory efforts than during relaxation. Peak inspiratory airflow usually preceded peak upward acceleration by 90-180 degrees. In 80% of runs with respiratory muscles voluntarily activated or relaxed, EMGs showed activity synchronous with OAA. Changes in periodic muscle activity coincided with changes in oscillatory airflow. We conclude that periodic muscle activity, probably a reflex response to body wall deformation during OAA, strongly influences the involuntary airflow synchronous with OAA.

  2. Decreased vascular smooth muscle cell density in medial degeneration of human abdominal aortic aneurysms.

    PubMed Central

    López-Candales, A.; Holmes, D. R.; Liao, S.; Scott, M. J.; Wickline, S. A.; Thompson, R. W.

    1997-01-01

    Abdominal aortic aneurysms (AAAs) are characterized by structural deterioration of the aortic wall leading to progressive aortic dilatation and eventual rupture. The histopathological changes in AAAs are particularly evident within the elastic media, which is normally dominated by vascular smooth muscle cells (SMCs). To determine whether a decrease in vascular SMCs contributes to medial degeneration, we measured SMC density in 21 normal and pathological human abdominal aortic tissue specimens using immunohistochemistry for alpha-SMC actin and direct cell counts (medial SMCs per high-power field (HPF)). Medial SMC density was not significantly different between normal aorta (n = 5; 199.5 +/- 14.9 SMCs/HPF) and atherosclerotic occlusive disease (n = 6; 176.4 +/- 13.9 SMCs/HPF), but it was reduced by 74% in AAA (n = 10; 50.9 +/- 6.1 SMCs/HPF; P < 0.01 versus normal aorta). Light and electron microscopy revealed no evidence of overt cellular necrosis, but SMCs in AAAs exhibited ultrastructural changes consistent with apoptosis. Using in situ end-labeling (ISEL) of fragmented DNA to detect apoptotic cells, up to 30% of aortic wall cells were ISEL positive in AAAs. By double-labeling techniques, many of these cells were alpha-actin-positive SMCs distributed throughout the degenerative media. In contrast, ISEL-positive cells were observed only within the intimal plaque in atherosclerotic occlusive disease. The amount of p53 protein detected by immunoblotting was increased nearly fourfold in AAA compared with normal aorta and atherosclerotic occlusive disease (P < 0.01), and immunoreactive p53 was localized to lymphocytes and residual SMCs in the aneurysm wall. Using reverse transcription polymerase chain reaction assays a substantial amount of p53 mRNA expression was observed in AAAs. These results demonstrate that medial SMC density is significantly decreased in human AAA tissues associated with evidence of SMC apoptosis and increased production of p53, a potential

  3. Muscle hardness characteristics of the masseter muscle after repetitive muscle activation: comparison to the biceps brachii muscle.

    PubMed

    Kashima, Koji; Higashinaka, Shuichi; Watanabe, Naoshi; Maeda, Sho; Shiba, Ryosuke

    2004-10-01

    The purpose of this study was to compare hardness characteristics of the masseter muscle to those of the biceps brachii muscle during repetitive muscle movements. Seventeen asymptomatic female subjects participated in this study. Each subject, on separate days, undertook a 5-minute unilateral chewing gum task on the right side and a 5-minute flexion-extension exercise on the right hand with a 2kg dumbbell. Using a handheld hardness meter, muscle hardness was measured in the right masseter and in the biceps brachii muscle at eight time points (before the task, immediately after the task, and at 1, 3, 5, 10, 30, and 60 minutes after the task), and the data obtained before and after the task on each muscle were compared. Comparisons of the normalized data were also performed between the two muscles at each time point. As a result, a significant increase in muscle hardness was seen at 1 minute after the task in the biceps brachii muscle (p=0.0093). In contrast, the masseter muscle showed a tendency to lower hardness, with the lowest point of hardness occurring at 10 minutes after the task (p = 0.0160). Between the two muscles, there was a difference in the normalized data immediately after the task, and at 1, 5, and 10 minutes after the task (0.01 muscle hardness characteristics of the masseter muscle completely differed from those of the biceps brachii muscle after repetitive muscle activation.

  4. Muscle activity characterization by laser Doppler Myography

    NASA Astrophysics Data System (ADS)

    Scalise, Lorenzo; Casaccia, Sara; Marchionni, Paolo; Ercoli, Ilaria; Primo Tomasini, Enrico

    2013-09-01

    Electromiography (EMG) is the gold-standard technique used for the evaluation of muscle activity. This technique is used in biomechanics, sport medicine, neurology and rehabilitation therapy and it provides the electrical activity produced by skeletal muscles. Among the parameters measured with EMG, two very important quantities are: signal amplitude and duration of muscle contraction, muscle fatigue and maximum muscle power. Recently, a new measurement procedure, named Laser Doppler Myography (LDMi), for the non contact assessment of muscle activity has been proposed to measure the vibro-mechanical behaviour of the muscle. The aim of this study is to present the LDMi technique and to evaluate its capacity to measure some characteristic features proper of the muscle. In this paper LDMi is compared with standard superficial EMG (sEMG) requiring the application of sensors on the skin of each patient. sEMG and LDMi signals have been simultaneously acquired and processed to test correlations. Three parameters has been analyzed to compare these techniques: Muscle activation timing, signal amplitude and muscle fatigue. LDMi appears to be a reliable and promising measurement technique allowing the measurements without contact with the patient skin.

  5. The magnetic field of gastrointestinal smooth muscle activity

    NASA Astrophysics Data System (ADS)

    Bradshaw, Alan; Ladipo, Jk; Richards, William; Wikswo, John

    1997-11-01

    The gastrointestinal (GI) tract controls the absorption and transport of ingested materials. Its function is determined largely by the electrical activity of the smooth muscle that lines the GI tract. GI electrical activity consists of an omnipresent slowly oscillating wave known as the basic electrical rhythm (BER) that modulates a higher-frequency spiking activity associated with muscle contraction. The BER has been shown to be a reliable indicator of intestinal viability, and thus, recording of smooth muscle activity may have clinical value. The BER is difficult to measure with cutaneous electrodes because layers of low-conductivity fat between the GI tract and the abdominal surface attenuate the potential. On the other hand, the magnetic field associated with GI electrical activity is mostly unaffected by intervening fat layers. We recorded the magnetic fields from GI activity in 12 volunteers using a multichannel Superconducting QUantum Interference Device (SQUID) magnetometer. Characteristics typical of gastric and intestinal BER were apparent in the data. Channels near the epigastrium recorded gastric BER, and channels in intestinal areas recorded small bowel BER. These results suggest that a single multichannel SQUID magnetometer is able to measure gastrointestinal electrical activity from multiple locations around the abdomen simultaneously.

  6. Respiratory muscle strength in the physically active elderly.

    PubMed

    Summerhill, Eleanor M; Angov, Nadia; Garber, Carol; McCool, F Dennis

    2007-12-01

    Advancing age is associated with a decline in the strength of the skeletal muscles, including those of respiration. Respiratory muscles can be strengthened with nonrespiratory activities. We therefore hypothesized that regular exercise in the elderly would attenuate this age-related decline in respiratory muscle strength. Twenty-four healthy subjects older than 65 years were recruited (11 males and 13 females). A comprehensive physical activity survey was administered, and subjects were categorized as active (n = 12) or inactive (n = 12). Each subject underwent testing of maximum inspiratory and expiratory pressures (PI(max) and PE(max)). Diaphragmatic thickness (tdi) was measured via two-dimensional B-mode ultrasound. There were no significant differences between the active and inactive groups with respect to age (75 vs. 73 years) or body weight (69.1vs. 69.9 kg). There were more women (9) than men (3) in the inactive group. Diaphragm thickness was greater in the active group (0.31 +/- 0.06 cm vs. 0.25 +/- 0.04 cm; p = 0.011). PE(max) and PI(max) were also greater in the active group (130 +/- 44 cm H(2)O vs. 80 +/- 24 cm H(2)O; p = 0.002; and 99 +/- 32 cm H(2)O vs. 75 +/- 14 cm H(2)O; p = 0.03). There was a positive association between PI(max )and tdi (r = 0.43, p = 0.03). Regular exercise was positively associated with diaphragm muscle thickness in this cohort. As PE(max) was higher in the active group, we postulate that recruitment of the diaphragm and abdominal muscles during nonrespiratory activities may be the source of this training effect.

  7. The effects of Pilates breathing trainings on trunk muscle activation in healthy female subjects: a prospective study

    PubMed Central

    Kim, Sung-Tae; Lee, Joon-Hee

    2017-01-01

    [Purpose] To investigate the effects of Pilates breathing on trunk muscle activation. [Subjects and Methods] Twenty-eight healthy female adults were selected for this study. Participants’ trunk muscle activations were measured while they performed curl-ups, chest-head lifts, and lifting tasks. Pilates breathing trainings were performed for 60 minutes per each session, 3 times per week for 2 weeks. Post-training muscle activations were measured by the same methods used for the pre-training muscle activations. [Results] All trunk muscles measured in this study had increased activities after Pilates breathing trainings. All activities of the transversus abdominis/internal abdominal oblique, and multifidus significantly increased. [Conclusion] Pilates breathing increased activities of the trunk stabilizer muscles. Activation of the trunk muscle indicates that practicing Pilates breathing while performing lifting tasks will reduce the risk of trunk injuries. PMID:28265138

  8. The effects of Pilates breathing trainings on trunk muscle activation in healthy female subjects: a prospective study.

    PubMed

    Kim, Sung-Tae; Lee, Joon-Hee

    2017-02-01

    [Purpose] To investigate the effects of Pilates breathing on trunk muscle activation. [Subjects and Methods] Twenty-eight healthy female adults were selected for this study. Participants' trunk muscle activations were measured while they performed curl-ups, chest-head lifts, and lifting tasks. Pilates breathing trainings were performed for 60 minutes per each session, 3 times per week for 2 weeks. Post-training muscle activations were measured by the same methods used for the pre-training muscle activations. [Results] All trunk muscles measured in this study had increased activities after Pilates breathing trainings. All activities of the transversus abdominis/internal abdominal oblique, and multifidus significantly increased. [Conclusion] Pilates breathing increased activities of the trunk stabilizer muscles. Activation of the trunk muscle indicates that practicing Pilates breathing while performing lifting tasks will reduce the risk of trunk injuries.

  9. Ultrasound-Derived Abdominal Muscle Thickness Better Detects Metabolic Syndrome Risk in Obese Patients than Skeletal Muscle Index Measured by Dual-Energy X-Ray Absorptiometry

    PubMed Central

    Ido, Ayumi; Nakayama, Yuki; Ishii, Kojiro; Iemitsu, Motoyuki; Sato, Koji; Fujimoto, Masahiro; Kurihara, Toshiyuki; Hamaoka, Takafumi; Satoh-Asahara, Noriko; Sanada, Kiyoshi

    2015-01-01

    Sarcopenia has never been diagnosed based on site-specific muscle loss, and little is known about the relationship between site-specific muscle loss and metabolic syndrome (MetS) risk factors. To this end, this cross-sectional study aimed to investigate the relationship between site-specific muscle size and MetS risk factors. Subjects were 38 obese men and women aged 40–82 years. Total body fat and lean body mass were assessed by whole-body dual-energy X-ray absorptiometry (DXA) scan. Muscle thickness (MTH) was measured using B-mode ultrasound scanning in six body regions. Subjects were classified into general obesity (GO) and sarcopenic obesity (SO) groups using the threshold values of one standard deviation below the sex-specific means of either MTH or skeletal muscle index (SMI) measured by DXA. MetS risk score was acquired by standardizing and summing the following continuously distributed variables: visceral fat area, mean blood pressure, HbA1c, and serum triglyceride / high density lipoprotein cholesterol, to obtain the Z-score. Multiple regression analysis revealed that the MetS risk score was independently associated with abdominal MTH in all subjects, but not with MTH in other muscle regions, including the thigh. Although HbA1c and the number of MetS risk factors in the SO group were significantly higher than those in the GO group, there were no significant differences between GO and SO groups as defined by SMI. Ultrasound-derived abdominal MTH would allow a better assessment of sarcopenia in obese patients and can be used as an alternative to the conventionally-used SMI measured by DXA. PMID:26700167

  10. Effect of exhalation exercise on trunk muscle activity and oswestry disability index of patients with chronic low back pain

    PubMed Central

    Kang, Jeong-Il; Jeong, Dae-Keun; Choi, Hyun

    2016-01-01

    [Purpose] This study investigated the effect of exhalation exercises on trunk muscle activity and Oswestry Disability Index by inducing trunk muscle activity through increasing intra-abdominal pressure and activating muscles, contributing to spinal stability. [Subjects and Methods] This intervention program included 20 male patients with chronic low back pain. A total of 10 subjects each were randomly assigned to an exhalation exercise group as the experimental group and a spinal stabilization exercise group as the control group. [Results] There were significant differences in the activities of the rectus abdominis, transverse abdominis, external oblique abdominal, and erector spinae muscles as well as in the Oswestry Disability Index within the experimental group. There were meaningful differences in the activities of the rectus abdominis, external oblique abdominal, and erector spinae muscles and in the Oswestry Disability Index within the control group. In addition, there was a meaningful intergroup difference in transverse abdominis muscle activity alone and in the Oswestry Disability Index. [Conclusion] The breathing exercise effectively increased muscle activity by training gross and fine motor muscles in the trunk. Moreover, it was verified as a very important element for strengthening body stability because it both released and prevented low back pain. PMID:27390406

  11. Subtype-Specific Estrogen Receptor-Mediated Vasodilator Activity in the Cephalic, Thoracic and Abdominal Vasculature of Female Rat

    PubMed Central

    Reslan, Ossama M.; Yin, Zongzhi; do Nascimento, Graciliano R. A.; Khalil, Raouf A.

    2013-01-01

    Estrogen receptors (ERs) mediate genomic and nongenomic vasodilator effects, but estrogen therapy may not provide systemic vascular protection. To test whether this is due to regional differences in ER distribution or vasodilator activity, cephalic (carotid), thoracic (thoracic aorta, pulmonary) and abdominal arteries (abdominal aorta, mesenteric, renal) from female Sprague-Dawley rats were prepared to measure contraction to phenylephrine (Phe), and relaxation to acetylcholine (ACh) and the ER activators 17β-estradiol (E2) (all ERs), PPT (ERα), DPN (ERβ) and G1 (GPR30). Phe caused contraction that was enhanced in endothelium-denuded aorta, supporting endothelial release of vasodilators. In cephalic and thoracic arteries, ACh relaxation was abolished by the NOS inhibitor L-NAME, suggesting a role of NO. In mesenteric vessels, ACh-induced relaxation was partly inhibited by L-NAME+COX inhibitor indomethacin and blocked by the K+ channel blocker tetraethylammonium (TEA), suggesting a hyperpolarization pathway. E2 and PPT caused similar relaxation in all vessels. DPN and G1 caused smaller relaxation that was more prominent in abdominal vessels. RT-PCR revealed variable ERα mRNA expression, and increased ERβ in carotid artery and GPR30 in abdominal arteries. Western blots revealed greater amounts of ERα, ERβ and GPR30 in abdominal arteries. In thoracic aorta, E2, PPT and DPN-induced relaxation was blocked by L-NAME, and was associated with increased nitrite/nitrate production, suggesting a role of NO. In abdominal vessels, E2, PPT, DPN and G1-induced relaxation persisted in L-NAME+indomethacin+TEA-treated or endothelium-denuded arteries, suggesting direct effect on vascular smooth muscle (VSM). E2, PPT, DPN, and G1 caused greater relaxation of KCl-induced contraction in abdominal vessels, suggesting inhibitory effects on Ca2+ entry. Thus, E2 and ERα stimulation produce similar relaxation of the cephalic, thoracic and abdominal arteries. In the cephalic and

  12. Muscle activity during the active straight leg raise (ASLR), and the effects of a pelvic belt on the ASLR and on treadmill walking.

    PubMed

    Hu, Hai; Meijer, Onno G; van Dieën, Jaap H; Hodges, Paul W; Bruijn, Sjoerd M; Strijers, Rob L; Nanayakkara, Prabath W; van Royen, Barend J; Wu, Wenhua; Xia, Chun

    2010-02-10

    Women with pregnancy-related pelvic girdle pain (PPP), or athletes with groin pain, may have trouble with the active straight leg raise (ASLR), for which a pelvic belt can be beneficial. How the problems emerge, or how the belt works, remains insufficiently understood. We assessed muscle activity during ASLR, and how it changes with a pelvic belt. Healthy nulligravidae (N=17) performed the ASLR, and walked on a treadmill at increasing speeds, without and with a belt. Fine-wire electromyography (EMG) was used to record activity of the mm. psoas, iliacus and transversus abdominis, while other hip and trunk muscles were recorded with surface EMG. In ASLR, all muscles were active. In both tasks, transverse and oblique abdominal muscles were less active with the belt. In ASLR, there was more activity of the contralateral m. biceps femoris, and in treadmill walking of the m. gluteus maximus in conditions with a belt. For our interpretation, we take our starting point in the fact that hip flexors exert a forward rotating torque on the ilium. Apparently, the abdominal wall was active to prevent such forward rotation. If transverse and oblique abdominal muscles press the ilia against the sacrum (Snijders' "force closure"), the pelvis may move as one unit in the sagittal plane, and also contralateral hip extensor activity will stabilize the ipsilateral ilium. The fact that transverse and oblique abdominal muscles were less active in conditions with a pelvic belt suggests that the belt provides such "force closure", thus confirming Snijders' theory.

  13. Segmenting the thoracic, abdominal and pelvic musculature on CT scans combining atlas-based model and active contour model

    NASA Astrophysics Data System (ADS)

    Zhang, Weidong; Liu, Jiamin; Yao, Jianhua; Summers, Ronald M.

    2013-03-01

    Segmentation of the musculature is very important for accurate organ segmentation, analysis of body composition, and localization of tumors in the muscle. In research fields of computer assisted surgery and computer-aided diagnosis (CAD), muscle segmentation in CT images is a necessary pre-processing step. This task is particularly challenging due to the large variability in muscle structure and the overlap in intensity between muscle and internal organs. This problem has not been solved completely, especially for all of thoracic, abdominal and pelvic regions. We propose an automated system to segment the musculature on CT scans. The method combines an atlas-based model, an active contour model and prior segmentation of fat and bones. First, body contour, fat and bones are segmented using existing methods. Second, atlas-based models are pre-defined using anatomic knowledge at multiple key positions in the body to handle the large variability in muscle shape. Third, the atlas model is refined using active contour models (ACM) that are constrained using the pre-segmented bone and fat. Before refining using ACM, the initialized atlas model of next slice is updated using previous atlas. The muscle is segmented using threshold and smoothed in 3D volume space. Thoracic, abdominal and pelvic CT scans were used to evaluate our method, and five key position slices for each case were selected and manually labeled as the reference. Compared with the reference ground truth, the overlap ratio of true positives is 91.1%+/-3.5%, and that of false positives is 5.5%+/-4.2%.

  14. The effects of modified wall squat exercises on average adults' deep abdominal muscle thickness and lumbar stability.

    PubMed

    Cho, Misuk

    2013-06-01

    [Purpose] The purpose of this study was to compare the effects of bridge exercises applying the abdominal drawing-in method and modified wall squat exercises on deep abdominal muscle thickness and lumbar stability. [Subjects] A total of 30 subjects were equally divided into an experimental group and a control group. [Methods] The experimental group completed modified wall squat exercises, and the control group performed bridge exercises. Both did so for 30 minutes three times per week over a six-week period. Both groups' transversus abdominis (Tra), internal oblique (IO), and multifidus muscle thickness were measured using ultrasonography, while their static lumbar stability and dynamic lumbar stability were measured using a pressure biofeedback unit. [Results] A comparison of the pre-intervention and post-intervention measures of the experimental group and the control group was made; the Tra and IO thicknesses were significantly different in both groups. [Conclusion] The modified wall squat exercise and bridge exercise affected the thicknesses of the Tra and the IO muscles. While the bridge exercise requirs space and a mattress to lie on, the modified wall squat exercise can be conveniently performed anytime.

  15. Associations between low back pain, urinary incontinence, and abdominal muscle recruitment as assessed via ultrasonography in the elderly

    PubMed Central

    Figueiredo, Vânia F.; Amorim, Juleimar S. C.; Pereira, Aline M.; Ferreira, Paulo H.; Pereira, Leani S. M.

    2015-01-01

    Background: Low back pain (LBP) and urinary incontinence (UI) are highly prevalent among elderly individuals. In young adults, changes in trunk muscle recruitment, as assessed via ultrasound imaging, may be associated with lumbar spine stability. Objective: To assess the associations between LBP, UI, and the pattern of transversus abdominis (TrA), internal (IO), and external oblique (EO) muscle recruitment in the elderly as evaluated by ultrasound imaging. Method: Fifty-four elderly individuals (mean age: 72±5.2 years) who complained of LBP and/or UI as assessed by the McGill Pain Questionnaire, Incontinence Questionnaire-Short Form, and ultrasound imaging were included in the study. The statistical analysis comprised a multiple linear regression model, and a p-value <0.05 was considered significant. Results: The regression models for the TrA, IO, and EO muscle thickness levels explained 2.0% (R2=0.02; F=0.47; p=0.628), 10.6% (R2=0.106; F=3.03; p=0.057), and 10.1% (R2=0.101; F=2.70; p=0.077) of the variability, respectively. None of the regression models developed for the abdominal muscles exhibited statistical significance. A significant and negative association (p=0.018; β=-0.0343) was observed only between UI and IO recruitment. Conclusion: These results suggest that age-related factors may have interfered with the findings of the study, thus emphasizing the need to perform ultrasound imaging-based studies to measure abdominal muscle recruitment in the elderly. PMID:25714438

  16. Microgravity effects on 'postural' muscle activity patterns

    NASA Technical Reports Server (NTRS)

    Layne, Charles S.; Spooner, Brian S.

    1994-01-01

    Changes in neuromuscular activation patterns associated with movements made in microgravity can contribute to muscular atrophy. Using electromyography (EMG) to monitor 'postural' muscles, it was found that free floating arm flexions made in microgravity were not always preceded by neuromuscular activation patterns normally observed during movements made in unit gravity. Additionally, manipulation of foot sensory input during microgravity arm flexion impacted upon anticipatory postural muscle activation.

  17. Abdominal muscle and epipubic bone function during locomotion in Australian possums: insights to basal mammalian conditions and Eutherian-like tendencies in Trichosurus.

    PubMed

    Reilly, Stephen M; McElroy, Eric J; White, Thomas D; Biknevicius, Audrone R; Bennett, Michael B

    2010-04-01

    Mammals have four hypaxial muscle layers that wrap around the abdomen between the pelvis, ribcage, and spine. However, the marsupials have epipubic bones extending anteriorly into the ventral hypaxial layers with two additional muscles extending to the ventral midline and femur. Comparisons of South American marsupials to basal eutherians have shown that all of the abdominal hypaxials are active bilaterally in resting ventilation. However, during locomotion marsupials employ an asymmetrical pattern of activity as the hypaxial muscles form a crosscouplet linkage that uses the epipubic bone as a lever to provide long-axis support of the body between diagonal limb couplets during each step. In basal eutherians, this system shifts off the femur and epipubic bones (which are lost) resulting in a shoulder to pelvis linkage associated with shifts in both the positions and activity patterns of the pectineus and rectus abdominis muscles during locomotion. In this study, we present data on hypaxial function in two species (Pseudocheirus peregrinus and Trichosurus vulpecula) representing the two major radiations of possums in Australia: the Pseudocheiridae (within the Petauroidea) and the Phalangeridae. Patterns of gait, motor activity, and morphology in these two Australian species were compared with previous work to examine the generality of 1) the crosscouplet lever system as the basal condition for the Marsupialia and 2) several traits hypothesized to be common to all mammals (hypaxial tonus during resting ventilation, ventilation to step synchrony during locomotion, and bilateral transversus abdominis activity during locomotor expiration). Our results validate the presence of the crosscouplet pattern and basic epipubic bone lever system in Australian possums and confirm the generality of basal mammalian patterns. However, several novelties discovered in Trichosurus, reveal that it exhibits an evolutionary transition to intermediate eutherian-like morphological and motor

  18. MUSCLE ACTIVATION PATTERNS DURING SUSPENSION TRAINING EXERCISES

    PubMed Central

    Harris, Sean; Ruffin, Elise; Brewer, Wayne

    2017-01-01

    Background Suspension training (ST) has been utilized over exercises performed on a stable surface to train multiple muscle groups simultaneously to increase muscle activation and joint stability. Hypothesis/Purpose The purpose of this study was to determine whether ST augments muscle activation compared to similar exercises performed on a stable surface. Study Design Cross-sectional study Methods Twenty-five healthy adults (male: 16; women: 9; BMI: 23.50 ± 2.48 kg/m2) had 16 pre-amplified wireless surface EMG electrodes placed bilaterally on: the pectoralis major (PM), middle deltoid (MD), serratus anterior (SA), obliques (OB), rectus abdominis (RA), gluteus maximus (GM), erector spinae (ES), and middle trapezius/rhomboids (MT). Each participant performed reference isometric exercises (Sorensen test, push-up, sit-up, and inverted row) to establish a baseline muscle contraction. Muscle activation was assessed during the following exercises: ST bridge, ST push-up, ST inverted row, ST plank, floor bridge, floor push-up, floor row, and floor plank. The root mean square (RMS) of each side for every muscle was averaged for data analysis. Multivariate analyses of variance (MANOVA) for each exercise with post-hoc comparisons were performed to compare muscle activation between each ST exercise and its stable surface counterpart. Results MANOVAs for all exercise comparisons showed statistically significant greater muscle activation in at least one muscle group during the ST condition. Post-hoc analyses revealed a statistically significant increase in muscle activation for the following muscles during the plank: OB (p = 0.021); Push-up: PM (p = 0.002), RA (p<0.0001), OB (p = 0.019), MT (p<0.0001), and ES (p = 0.006); Row: MD (p = 0.016), RA (p = 0.059), and OB (p = 0.027); and Bridge: RA (p = 0.013) and ES (p<0.0001). Conclusions Performing ST exercises increases muscle activation of selected muscles when compared to exercises performed on a stable surface. Level of

  19. Abdominal strengthening using the AbVice machine as measured by surface electromyographic activation levels.

    PubMed

    Avedisian, Lori; Kowalsky, Don S; Albro, Richard C; Goldner, Daniel; Gill, Robert C

    2005-08-01

    Twenty-four college students served as subjects in a study that examined the effect of a prototypical abdominal muscle strengthening device (AbVice) compared with other devices currently on the market. The purpose of the present study was to investigate a prototypical device (AbVice) that incorporates contraction of the hamstring and gluteal musculature in conjunction with the abdominals, which may assist in decreasing activation of the hip flexors by allowing greater activity levels of the abdominal musculature via the theory of reflex inhibition, compared with other devices currently available on the market (AbRoller and AbRocker). The repeated-measures study included 17 women and 7 men who ranged in age from 20-23 years (mean +/- SD age, 21.3 +/- 1.5 years). Each subject underwent a single session of data collection during which they completed 10 repetitions of abdominal crunches per device. Subjects completed 4 different crunch sets (AbRocker, AbRoller, standard crunch, AbVice). Counterbalancing of the device was used to negate the effect of fatigue. Speed of repetitions was ensured via use of a metronome set at 40 b.min(-1) to permit similar contraction times and rest periods between repetitions. Rest between conditions was 3 minutes. Mean activation levels of surface electromyography (EMG) were recorded for each condition at the following locations on the right side of the body: rectus abdominis 2.5 cm superior to the umbilicus, rectus abdominis 2.5 cm inferior to the umbilicus, external oblique abdominis 1.0 cm medial to the anterior superior iliac spine, and external oblique abdominis less than 1.0 cm superior to the inguinal ligament. Mean (SD) activation was 1,165.21 mV (634.60 mV) with the AbVice, 242.92 mV (263.03 mV) with the AbRocker, 753.29 mV (514.80 mV) with the standard crunch, and 757.67 mV (542.85 mV) with the AbRoller. Broken down by sex, women had the following mean (SD) EMG values: 1,079.76 mV (705.02 mV) with the AbVice, 680.35 mV (535.35 m

  20. Effect of using a suspension training system on muscle activation during the performance of a front plank exercise.

    PubMed

    Byrne, Jeannette M; Bishop, Nicole S; Caines, Andrew M; Crane, Kalynn A; Feaver, Ashley M; Pearcey, Gregory E P

    2014-11-01

    The objective of the study was to examine the effect of suspension training on muscle activation during performance of variations of the plank exercise. Twenty-one participants took part. All individuals completed 2 repetitions each of 4 different plank exercises that consisted of a floor based plank, or planks with arms suspended, feet suspended, or feet and arms suspended using a TRX Suspension System. During plank performance, muscle activation was recorded from rectus abdominis, external oblique, rectus femoris, and serratus anterior (SA) muscles using electromyography. All planks were performed for a total of 3 seconds. Resulting muscle activation data were amplitude normalized, and root mean square activation was then determined over the full 3 second duration of the exercise. A significant main effect of plank type was found for all muscles. Post hoc analysis and effect size examination indicated that abdominal muscle activation was higher in all suspended conditions compared to the floor based plank. The highest level of abdominal muscle activation occurred in the arms suspended and arms/feet suspended conditions, which did not differ from one another. Rectus femoris activation was greatest during the arms suspended condition, whereas SA activity peaked during normal and feet suspended planks. These results indicate that suspension training as performed in this study seems to be an effective means of increasing muscle activation during the plank exercise. Contrary to expectations, the additional instability created by suspending both the arms and feet did not result in any additional abdominal muscle activation. These findings have implications in prescription and progression of core muscle training programs.

  1. Heterogeneity of muscle activity during sedentary behavior.

    PubMed

    Pesola, Arto J; Laukkanen, Arto; Tikkanen, Olli; Finni, Taija

    2016-11-01

    Replacing sitting by standing has been hypothesized to reduce the health risks of sitting, based on the assumption that muscles are passive during sitting and active during standing. Interventions have been more effective in overweight (OW) than in normal weight (NW) individuals, but subjects' muscle activities have not been quantified. This study compared quadriceps and hamstring muscle electromyographic (EMG) activity between 57 NW (body mass index (BMI) 22.5 ± 1.5 kg/m(2), female n = 36) and 27 OW (BMI 28.4 ± 2.9 kg/m(2), female n = 8) subjects during non-fatiguing standing (15 s, EMGstanding) and sitting (30 min). EMG amplitude was normalized to EMG measured during maximal isometric knee extension and flexion (% EMGMVC), and sitting muscle inactivity and bursts were determined using 4 thresholds (60% or 90% EMGstanding and 1% or 2% EMGMVC). Comparisons were adjusted for sex, age, knee extension strength, and the individual threshold. Standing EMG amplitude was 36% higher in OW (1.9% ± 1.5% EMGMVC) than in NW (1.4% ± 1.4% EMGMVC, P < 0.05) subjects. During sitting, muscles were inactive 89.8% ± 12.7% of the measurement time with 12.7 ± 14.2 bursts/min across all thresholds. On average, 6% more activity was recorded in NW than in OW individuals for 3 of the 4 thresholds (P < 0.05 for 60% or 90% EMGstanding and 1% EMGMVC). In conclusion, the OW group had higher muscle activity amplitude during standing but more muscle inactivity during sitting for 3/4 of the thresholds tested. Interventions should test whether the observed heterogeneity in muscle activity affects the potential to gain cardiometabolic benefits from replacing sitting with standing.

  2. Muscle spindle and fusimotor activity in locomotion.

    PubMed

    Ellaway, Peter H; Taylor, Anthony; Durbaba, Rade

    2015-08-01

    Mammals may exhibit different forms of locomotion even within a species. A particular form of locomotion (e.g. walk, run, bound) appears to be selected by supraspinal commands, but the precise pattern, i.e. phasing of limbs and muscles, is generated within the spinal cord by so-called central pattern generators. Peripheral sense organs, particularly the muscle spindle, play a crucial role in modulating the central pattern generator output. In turn, the feedback from muscle spindles is itself modulated by static and dynamic fusimotor (gamma) neurons. The activity of muscle spindle afferents and fusimotor neurons during locomotion in the cat is reviewed here. There is evidence for some alpha-gamma co-activation during locomotion involving static gamma motoneurons. However, both static and dynamic gamma motoneurons show patterns of modulation that are distinct from alpha motoneuron activity. It has been proposed that static gamma activity may drive muscle spindle secondary endings to signal the intended movement to the central nervous system. Dynamic gamma motoneuron drive appears to prime muscle spindle primary endings to signal transitions in phase of the locomotor cycle. These findings come largely from reduced animal preparations (decerebrate) and require confirmation in freely moving intact animals.

  3. Comparison of trunk muscle reflex activation patterns between active and passive trunk flexion-extension loading conditions.

    PubMed

    Olson, Michael W

    2014-04-01

    The aim of the present study was to determine the effects of trunk flexion-extension loading on the neuromuscular reflexive latencies and amplitude responses of the trunk musculature. Eighteen male and female subjects (18-27yrs) participated in active and passive trunk flexion extension, performed ∼7days apart. Subjects performed 60 trunk flexion-extension repetitions. Surface electromyography (EMG) was collected bilaterally from paraspinal and abdominal muscles. In the active condition, subjects volitionally moved their trunks, while in the passive condition the dynamometer controlled the movements. The trunk was perturbed before and immediately after 30 repetitions. Latency of muscle onset, latency of first peak, latency of maximum peak, and peak EMG amplitude were evaluated. No differences between conditions, sides, or perturbation session were apparent. Overall latencies were shorter in females (p<.05) and abdominal muscles compared to paraspinals (p<.05). Thoracic paraspinal muscle amplitudes were greater than all other muscles (p<.05). Based upon the present results, the neuromuscular system engages trunk flexor muscles prior to the paraspinals in order to provide possible stabilization of the trunk when flexor moments are generated. Overall, the results indicate no difference in response of the neuromuscular system to active or passive repetitive loading.

  4. Inhibition of the mTOR pathway in abdominal aortic aneurysm: implication of smooth muscle cell contractile phenotype, inflammation and aneurysm expansion.

    PubMed

    Li, Guangxin; Qin, Lingfeng; Wang, Lei; Li, Xuan; Caulk, Alexander W; Zhang, Jian; Chen, Pei-Yu; Xin, Shijie

    2017-02-17

    The development of effective pharmacological treatment of abdominal aortic aneurysm (AAA) potentially offers great benefit to patients with pre-aneurysmal aortic dilation by slowing the expansion of aneurysms and reducing the need for surgery. To date, therapeutic targets for slowing aortic dilation have had low efficacy. Thus, in this study, we aim to elucidate possible mechanisms driving aneurysm progression in order to identify potential targets for pharmacological intervention. We demonstrate that mTOR signaling is over activated in aortic smooth muscle cells (SMCs) which contributes to murine AAA. Rapamycin, a typical mTOR pathway inhibitor, dramatically limits the expansion of the abdominal aorta following intraluminal elastase perfusion. Furthermore, reduction of aortic diameter is achieved by inhibition of the mTOR pathway, which preserves and/or restores the contractile phenotype of SMCs and downregulates macrophage infiltration, MMPs expression, and inflammatory cytokine production. Taken together, these results highlight the important role of the mTOR cascade in aneurysm progression and the potential application of rapamycin as a therapeutic candidate for AAA.

  5. Transneuronal tracing of neural pathways influencing both diaphragm and genioglossal muscle activity in the ferret.

    PubMed

    Shintani, T; Anker, A R; Billig, I; Card, J P; Yates, B J

    2003-10-01

    In prior experiments that employed the transneuronal transport of isogenic recombinants of pseudorabies virus (PRV), we demonstrated that neurons located ventrally in the medial medullary reticular formation (MRF) of the ferret provide collateralized projections to both diaphragm and abdominal muscle motoneurons as well as to multiple abdominal muscle motoneuron pools. The goal of the present study was to determine whether single MRF neurons also furnish inputs to diaphragm motoneurons and those innervating an airway muscle with inspiratory-related activity: the tongue protruder genioglossus. For this purpose, PRV recombinants expressing unique reporters (beta-galactosidase or enhanced green fluorescent protein) were injected into either the diaphragm or the genioglossal muscle. The virus injections produced transneuronal infection of overlapping populations of MRF neurons. A small proportion of these neurons (<15%) was infected by both PRV recombinants, which indicated that they provide collateralized inputs to genioglossal and diaphragm motoneurons. These findings show that, whereas some MRF neurons simultaneously influence the activity of upper airway and respiratory pump muscles, other cells in this brain stem region independently contribute to diaphragm and genioglossal muscle contraction regulation.

  6. Effects of diaphragm stretching on posterior chain muscle kinematics and rib cage and abdominal excursion: a randomized controlled trial

    PubMed Central

    González-Álvarez, Francisco J.; Valenza, Marie C.; Torres-Sánchez, Irene; Cabrera-Martos, Irene; Rodríguez-Torres, Janet; Castellote-Caballero, Yolanda

    2016-01-01

    ABSTRACT Background Few studies have explored the effects of stretching techniques on diaphragm and spine kinematics. Objective To determine whether the application of diaphragm stretching resulted in changes in posterior chain muscle kinematics and ribcage and abdominal excursion in healthy subjects. Method Eighty healthy adults were included in this randomized clinical trial. Participants were randomized into two groups: the experimental group, which received a diaphragmatic stretching technique, or the placebo group, which received a sham-ultrasound procedure. The duration of the technique, the position of participants, and the therapist who applied the technique were the same for both treatments. Participant assessment (cervical range of movement, lumbar flexibility, flexibility of the posterior chain, and rib cage and abdominal excursion) was performed at baseline and immediately after the intervention by a blinded assessor. Results The mean between-group difference [95% CI] for the ribcage excursion after technique at xiphoid level was 2.48 [0.97 to 3.99], which shows significant differences in this outcome. The remaining between-group analysis showed significant differences in cervical extension, right and left flexion, flexibility of the posterior chain, and ribcage excursion at xiphoid level (p<0.05) in favor of the experimental group. Conclusion Diaphragm stretching generates a significant improvement in cervical extension, right and left cervical flexion, flexibility of the posterior chain, and ribcage excursion at xiphoid level compared to a placebo technique in healthy adults. PMID:27333481

  7. Alternative exon-encoding regions of Locusta migratoria muscle myosin modulate the pH dependence of ATPase activity.

    PubMed

    Li, J; Lu, Z; He, J; Chen, Q; Wang, X; Kang, L; Li, X-D

    2016-12-01

    Whereas the vertebrate muscle myosin heavy chains (MHCs) are encoded by a family of Mhc genes, most insects examined to date contain a single Mhc gene and produce all of the different MHC isoforms by alternative RNA splicing. Here, we found that the migratory locust, Locusta migratoria, has one Mhc gene, which contains 41 exons, including five alternative exclusive exons and one differently included penultimate exon, and potentially encodes 360 MHC isoforms. From the adult L. migratoria, we identified 14 MHC isoforms (including two identical isoforms): four from flight muscle (the thorax dorsal longitudinal muscle), three from jump muscle (the hind leg extensor tibiae muscle) and seven from the abdominal intersegmental muscle. We purified myosins from flight muscle and jump muscle and characterized their motor activities. At neutral pH, the flight and the jump muscle myosins displayed similar levels of in vitro actin-gliding activity, whereas the former had a slightly higher actin-activated ATPase activity than the latter. Interestingly, the pH dependences of the actin-activated ATPase activity of these two myosins are different. Because the dominant MHC isoforms in these two muscles are identical except for the two alternative exon-encoding regions, we propose that these two alternative regions modulate the pH dependence of L. migratoria muscle myosin.

  8. Whole-body electromyostimulation as a means to impact muscle mass and abdominal body fat in lean, sedentary, older female adults: subanalysis of the TEST-III trial

    PubMed Central

    Kemmler, Wolfgang; von Stengel, Simon

    2013-01-01

    Background The primary aim of this study was to determine the effect of 12 months of whole-body electromyostimulation (WB-EMS) exercise on appendicular muscle mass and abdominal fat mass in subjects specifically at risk for sarcopenia and abdominal obesity, but unable or unwilling to exercise conventionally. Methods Forty-six lean, nonsportive (<60 minutes of exercise per week), elderly women (aged 75 ± 4 years) with abdominal obesity according to International Diabetes Federation criteria were randomly assigned to either a WB-EMS group (n=23) which performed 18 minutes of intermittent, bipolar WB-EMS (85 Hz) three sessions in 14 days or an “active” control group (n=23). Whole-body and regional body composition was assessed by dual energy X-ray absorptiometry to determine appendicular muscle mass, upper leg muscle mass, abdominal fat mass, and upper leg fat mass. Maximum strength of the leg extensors was determined isometrically by force plates. Results After 12 months, significant intergroup differences were detected for the primary end-points of appendicular muscle mass (0.5% ± 2.0% for the WB-EMS group versus −0.8% ± 2.0% for the control group, P=0.025) and abdominal fat mass (−1.2% ± 5.9% for the WB-EMS group versus 2.4% ± 5.8% for the control group, P=0.038). Further, upper leg lean muscle mass changed favorably in the WB-EMS group (0.5% ± 2.5% versus −0.9% ± 1.9%, in the control group, P=0.033), while effects for upper leg fat mass were borderline nonsignificant (−0.8% ± 3.5% for the WB-EMS group versus 1.0% ± 2.6% for the control group, P=0.050). With respect to functional parameters, the effects for leg extensor strength were again significant, with more favorable changes in the WB-EMS group (9.1% ± 11.2% versus 1.0% ± 8.1% in the control group, P=0.010). Conclusion In summary, WB-EMS showed positive effects on the parameters of sarcopenia and regional fat accumulation. Further, considering the good acceptance of this technology by

  9. Effect of altering starting length and activation timing of muscle on fiber strain and muscle damage.

    PubMed

    Butterfield, Timothy A; Herzog, Walter

    2006-05-01

    Muscle strain injuries are some of the most frequent injuries in sports and command a great deal of attention in an effort to understand their etiology. These injuries may be the culmination of a series of subcellular events accumulated through repetitive lengthening (eccentric) contractions during exercise, and they may be influenced by a variety of variables including fiber strain magnitude, peak joint torque, and starting muscle length. To assess the influence of these variables on muscle injury magnitude in vivo, we measured fiber dynamics and joint torque production during repeated stretch-shortening cycles in the rabbit tibialis anterior muscle, at short and long muscle lengths, while varying the timing of activation before muscle stretch. We found that a muscle subjected to repeated stretch-shortening cycles of constant muscle-tendon unit excursion exhibits significantly different joint torque and fiber strains when the timing of activation or starting muscle length is changed. In particular, measures of fiber strain and muscle injury were significantly increased by altering activation timing and increasing the starting length of the muscle. However, we observed differential effects on peak joint torque during the cyclic stretch-shortening exercise, as increasing the starting length of the muscle did not increase torque production. We conclude that altering activation timing and muscle length before stretch may influence muscle injury by significantly increasing fiber strain magnitude and that fiber dynamics is a more important variable than muscle-tendon unit dynamics and torque production in influencing the magnitude of muscle injury.

  10. Changes in the activity of trunk and hip extensor muscles during bridge exercises with variations in unilateral knee joint angle

    PubMed Central

    Kim, Juseung; Park, Minchul

    2016-01-01

    [Purpose] This study compared abdominal and hip extensor muscle activity during a bridge exercise with various knee joint angles. [Subjects and Methods] Twenty-two healthy male subjects performed a bridge exercise in which the knee joint angle was altered. While subjects performed the bridge exercise, external oblique, internal oblique, gluteus maximus, and semitendinosus muscle activity was measured using electromyography. [Results] The bilateral external and internal oblique muscle activity was significantly higher at 0° knee flexion compared to 120°, 90°, and 60°. The bilateral gluteus maximus muscle activity was significantly different at 0° of knee flexion compared to 120°, 90°, and 60°. The ipsilateral semitendinosus muscle activity was significantly increased at 90° and 60° of knee flexion compared to 120°, and significantly decreased at 0° knee flexion compared with 120°, 90°, and 60°. The contralateral semitendinosus muscle activity was significantly higher at 60° of knee flexion than at 120°, and significantly higher at 0° of knee flexion than at 120°, 90°, and 60°. [Conclusion] Bridge exercises performed with knee flexion less than 90° may be used to train the ipsilateral semitendinosus. Furthermore, bridge exercise performed with one leg may be used to train abdominal and hip extensor muscles. PMID:27799688

  11. Neck Muscle Activation Levels During Frontal Impacts

    DTIC Science & Technology

    2004-09-01

    right and left upper trapezius and sternocleidomastoid . Amplitude and frequency components of the signals were evaluated to determine the amount of...Gx acceleration levels. The trapezius produced more force than the sternocleidomastoid . Activity of both muscle groups was synchronized, by their...dynamic environment. The role of upper trapezius and sternocleidomastoid (SCM) during long-duration head and neck loading situations has been

  12. The effects of Juchumseogi and Juchumseo Jireugi motions of taekwondo on muscle activation of paraspinal muscles.

    PubMed

    Baek, Jongmyeng; Lee, Jaeseok; Kim, Jonghyun; Kim, Jeonghun; Han, Dongwook; Byun, Sunghak

    2015-09-01

    [Purpose] The purpose of this study is to examine the effects of Juchumseogi and Juchumseo Jireugi motions on muscle activation of the paraspinal muscles. [Subjects] The subjects of this study were 20 healthy male students who listened to an explanation of the study methods and the purpose of the experiment, and agreed to participate in the study. [Methods] Muscle activation measurements of the paraspinal muscles at C3, T7, and L3 were taken while standing still and while performing Juchumseogi and Juchumseo Jireugi movements. The Juchumseogi and Juchumseo Jireugi motions were performed 3 times, and its mean value was used for analysis. [Results] The right and left muscle activation of paraspinal muscles induced by Juchumseogi and Juchumseo Jireugi motions in C3 and T7 were significantly higher than those induced by just standing. Muscle activation of paraspinal muscles induced by Juchumseo Jireugi motions in C3, T7, and L3 were significantly higher than those induced by Juchumseogi alone. The right and left muscle activation of paraspinal muscles induced by Juchumseo Jireugi motion in C3, T7, and L3 were significantly higher than those induced by standing and Juchumseogi alone. [Conclusion] This study demonstrated that Juchumseogi and Juchumseo Jireugi motions of Taekwondo could increase muscle activation of paraspinal muscles, and Juchumseo Jireugi motions were more effective for enhancing muscle activation of paraspinal muscles.

  13. The effects of Juchumseogi and Juchumseo Jireugi motions of taekwondo on muscle activation of paraspinal muscles

    PubMed Central

    Baek, Jongmyeng; Lee, Jaeseok; Kim, Jonghyun; Kim, Jeonghun; Han, Dongwook; Byun, Sunghak

    2015-01-01

    [Purpose] The purpose of this study is to examine the effects of Juchumseogi and Juchumseo Jireugi motions on muscle activation of the paraspinal muscles. [Subjects] The subjects of this study were 20 healthy male students who listened to an explanation of the study methods and the purpose of the experiment, and agreed to participate in the study. [Methods] Muscle activation measurements of the paraspinal muscles at C3, T7, and L3 were taken while standing still and while performing Juchumseogi and Juchumseo Jireugi movements. The Juchumseogi and Juchumseo Jireugi motions were performed 3 times, and its mean value was used for analysis. [Results] The right and left muscle activation of paraspinal muscles induced by Juchumseogi and Juchumseo Jireugi motions in C3 and T7 were significantly higher than those induced by just standing. Muscle activation of paraspinal muscles induced by Juchumseo Jireugi motions in C3, T7, and L3 were significantly higher than those induced by Juchumseogi alone. The right and left muscle activation of paraspinal muscles induced by Juchumseo Jireugi motion in C3, T7, and L3 were significantly higher than those induced by standing and Juchumseogi alone. [Conclusion] This study demonstrated that Juchumseogi and Juchumseo Jireugi motions of Taekwondo could increase muscle activation of paraspinal muscles, and Juchumseo Jireugi motions were more effective for enhancing muscle activation of paraspinal muscles. PMID:26504295

  14. The association of pre-operative physical fitness and physical activity with outcome after scheduled major abdominal surgery.

    PubMed

    Dronkers, J J; Chorus, A M J; van Meeteren, N L U; Hopman-Rock, M

    2013-01-01

    We studied whether reported physical activity and measurements of fitness (hand, leg and inspiration) were associated with postoperative in-hospital mortality, length of stay and discharge destination in 169 patients after major oncological abdominal surgery. In multivariate analysis, adequate activity level (OR 5.5, 95% CI 1.4-21.9) and inspiratory muscle endurance (OR 5.2, 95% CI 1.4-19.1) were independently associated with short-term mortality, whereas conventional factors, such as age and heart disease, were not. Adequate activity level (OR 6.7, 95% CI 1.4-3.0) was also independently associated with discharge destination. The factors that were independently associated with a shorter length of hospital stay were as follows: absence of chronic obstructive pulmonary disease (HR 0.6, 95% CI 0.3-1.1); adequate activity level (HR 0.6, 95% CI 0.4-0.8); and inspiratory muscle strength (HR 0.6, 95% CI 0.5-0.9). For all postoperative outcomes physical activity and fitness significantly improved the predictive value compared with known risk factors, such as age and comorbidities. We conclude that pre-operative questionnaires of physical activity and measurements of fitness contribute to the prediction of postoperative outcomes.

  15. Muscle Activation Patterns During Different Squat Techniques.

    PubMed

    Slater, Lindsay V; Hart, Joseph M

    2017-03-01

    Slater, LV, and Hart, JM. Muscle activation patterns during different squat techniques. J Strength Cond Res 31(3): 667-676, 2017-Bilateral squats are frequently used exercises in sport performance programs. Lower extremity muscle activation may change based on knee alignment during the performance of the exercise. The purpose of this study was to compare lower extremity muscle activation patterns during different squat techniques. Twenty-eight healthy, uninjured subjects (19 women, 9 men, 21.5 ± 3 years, 170 ± 8.4 cm, 65.7 ± 11.8 kg) volunteered. Electromyography (EMG) electrodes were placed on the vastus lateralis, vastus medialis, rectus femoris, biceps femoris, and the gastrocnemius of the dominant leg. Participants completed 5 squats while purposefully displacing the knee anteriorly (AP malaligned), 5 squats while purposefully displacing the knee medially (ML malaligned) and 5 squats with control alignment (control). Normalized EMG data (MVIC) were reduced to 100 points and represented as percentage of squat cycle with 50% representing peak knee flexion and 0 and 99% representing fully extended. Vastus lateralis, medialis, and rectus femoris activity decreased in the medio-lateral (ML) malaligned squat compared with the control squat. In the antero-posterior (AP) malaligned squat, the vastus lateralis, medialis, and rectus femoris activity decreased during initial descent and final ascent; however, vastus lateralis and rectus femoris activation increased during initial ascent compared with the control squat. The biceps femoris and gastrocnemius displayed increased activation during both malaligned squats compared with the control squat. In conclusion, participants had altered muscle activation patterns during squats with intentional frontal and sagittal malalignment as demonstrated by changes in quadriceps, biceps femoris, and gastrocnemius activation during the squat cycle.

  16. Comparative Sensitivity Analysis of Muscle Activation Dynamics

    PubMed Central

    Rockenfeller, Robert; Günther, Michael; Schmitt, Syn; Götz, Thomas

    2015-01-01

    We mathematically compared two models of mammalian striated muscle activation dynamics proposed by Hatze and Zajac. Both models are representative for a broad variety of biomechanical models formulated as ordinary differential equations (ODEs). These models incorporate parameters that directly represent known physiological properties. Other parameters have been introduced to reproduce empirical observations. We used sensitivity analysis to investigate the influence of model parameters on the ODE solutions. In addition, we expanded an existing approach to treating initial conditions as parameters and to calculating second-order sensitivities. Furthermore, we used a global sensitivity analysis approach to include finite ranges of parameter values. Hence, a theoretician striving for model reduction could use the method for identifying particularly low sensitivities to detect superfluous parameters. An experimenter could use it for identifying particularly high sensitivities to improve parameter estimation. Hatze's nonlinear model incorporates some parameters to which activation dynamics is clearly more sensitive than to any parameter in Zajac's linear model. Other than Zajac's model, Hatze's model can, however, reproduce measured shifts in optimal muscle length with varied muscle activity. Accordingly we extracted a specific parameter set for Hatze's model that combines best with a particular muscle force-length relation. PMID:26417379

  17. Lower extremity muscle activation during baseball pitching.

    PubMed

    Campbell, Brian M; Stodden, David F; Nixon, Megan K

    2010-04-01

    The purpose of this study was to investigate muscle activation levels of select lower extremity muscles during the pitching motion. Bilateral surface electromyography data on 5 lower extremity muscles (biceps femoris, rectus femoris, gluteus maximus, vastus medialis, and gastrocnemius) were collected on 11 highly skilled baseball pitchers and compared with individual maximal voluntary isometric contraction (MVIC) data. The pitching motion was divided into 4 distinct phases: phase 1, initiation of pitching motion to maximum stride leg knee height; phase 2, maximum stride leg knee height to stride foot contact (SFC); phase 3, SFC to ball release; and phase 4, ball release to 0.5 seconds after ball release (follow-through). Results indicated that trail leg musculature elicited moderate to high activity levels during phases 2 and 3 (38-172% of MVIC). Muscle activity levels of the stride leg were moderate to high during phases 2-4 (23-170% of MVIC). These data indicate a high demand for lower extremity strength and endurance. Specifically, coaches should incorporate unilateral and bilateral lower extremity exercises for strength improvement or maintenance and to facilitate dynamic stabilization of the lower extremities during the pitching motion.

  18. The functional coupling of the deep abdominal and paraspinal muscles: the effects of simulated paraspinal muscle contraction on force transfer to the middle and posterior layer of the thoracolumbar fascia.

    PubMed

    Vleeming, A; Schuenke, M D; Danneels, L; Willard, F H

    2014-10-01

    The thoracolumbar fascia (TLF) consists of aponeurotic and fascial layers that interweave the paraspinal and abdominal muscles into a complex matrix stabilizing the lumbosacral spine. To better understand low back pain, it is essential to appreciate how these muscles cooperate to influence lumbopelvic stability. This study tested the following hypotheses: (i) pressure within the TLF's paraspinal muscular compartment (PMC) alters load transfer between the TLF's posterior and middle layers (PLF and MLF); and (ii) with increased tension of the common tendon of the transversus abdominis (CTrA) and internal oblique muscles and incremental PMC pressure, fascial tension is primarily transferred to the PLF. In cadaveric axial sections, paraspinal muscles were replaced with inflatable tubes to simulate paraspinal muscle contraction. At each inflation increment, tension was created in the CTrA to simulate contraction of the deep abdominal muscles. Fluoroscopic images and load cells captured changes in the size, shape and tension of the PMC due to inflation, with and without tension to the CTrA. In the absence of PMC pressure, increasing tension on the CTrA resulted in anterior and lateral movement of the PMC. PMC inflation in the absence of tension to the CTrA resulted in a small increase in the PMC perimeter and a larger posterior displacement. Combining PMC inflation and tension to the CTrA resulted in an incremental increase in PLF tension without significantly altering tension in the MLF. Paraspinal muscle contraction leads to posterior displacement of the PLF. When expansion is combined with abdominal muscle contraction, the CTrA and internal oblique transfers tension almost exclusively to the PLF, thereby girdling the paraspinal muscles. The lateral border of the PMC is restrained from displacement to maintain integrity. Posterior movement of the PMC represents an increase of the PLF extension moment arm. Dysfunctional paraspinal muscles would reduce the posterior

  19. Patterns of muscle activity for digital coarticulation

    PubMed Central

    Winges, Sara A.; Furuya, Shinichi; Faber, Nathaniel J.

    2013-01-01

    Although piano playing is a highly skilled task, basic features of motor pattern generation may be shared across tasks involving fine movements, such as handling coins, fingering food, or using a touch screen. The scripted and sequential nature of piano playing offered the opportunity to quantify the neuromuscular basis of coarticulation, i.e., the manner in which the muscle activation for one sequential element is altered to facilitate production of the preceding and subsequent elements. Ten pianists were asked to play selected pieces with the right hand at a uniform tempo. Key-press times were recorded along with the electromyographic (EMG) activity from seven channels: thumb flexor and abductor muscles, a flexor for each finger, and the four-finger extensor muscle. For the thumb and index finger, principal components of EMG waveforms revealed highly consistent variations in the shape of the flexor bursts, depending on the type of sequence in which a particular central key press was embedded. For all digits, the duration of the central EMG burst scaled, along with slight variations across subjects in the duration of the interkeystroke intervals. Even within a narrow time frame (about 100 ms) centered on the central EMG burst, the exact balance of EMG amplitudes across multiple muscles depended on the nature of the preceding and subsequent key presses. This fails to support the idea of fixed burst patterns executed in sequential phases and instead provides evidence for neuromuscular coarticulation throughout the time course of a hand movement sequence. PMID:23596338

  20. Electromyographic analysis of four popular abdominal exercises.

    PubMed

    Piering, A W; Janowski, A P; Wehrenberg, W B; Moore, M T; Snyder, A C

    1993-01-01

    This study was designed to evaluate the effects of four specific sit-up exercises on muscular activity of the rectus abdominis. Pairs of surface electrodes were placed unilaterally on four quadrants of the rectus abdominis, delimited by tendinous inscriptions, in four male subjects. Electromyographic (EMG) recordings were taken while the subjects performed four different abdominal exercises. Each abdominal exercise was hypothesized to have a specific effect on one of the four quadrants of the rectus abdominis. The four exercises analyzed were: 1) long lying crunch, 2) bent knee crunch, 3) leg raise, and 4) vertical leg crunch. Analysis of the standardized EMG recordings demonstrated no significant differences in the mean muscle activity between the four different quadrants, in the mean muscle activity between the four different exercises, and in interactions between the exercises and the quadrants of the rectus abdominis. We conclude that none of the four abdominal exercises studied are specific for strengthening individual muscle quadrants of the rectus abdominis.

  1. Arm position influences the activation patterns of trunk muscles during trunk range-of-motion movements.

    PubMed

    Siu, Aaron; Schinkel-Ivy, Alison; Drake, Janessa Dm

    2016-10-01

    To understand the activation patterns of the trunk musculature, it is also important to consider the implications of adjacent structures such as the upper limbs, and the muscles that act to move the arms. This study investigated the effects of arm positions on the activation patterns and co-activation of the trunk musculature and muscles that move the arm during trunk range-of-motion movements (maximum trunk axial twist, flexion, and lateral bend). Fifteen males and fifteen females, asymptomatic for low back pain, performed maximum trunk range-of-motion movements, with three arm positions for axial twist (loose, crossed, abducted) and two positions for flexion and lateral bend (loose, crossed). Electromyographical data were collected for eight muscles bilaterally, and activation signals were cross-correlated between trunk muscles and the muscles that move the arms (upper trapezius, latissimus dorsi). Results revealed consistently greater muscle co-activation (higher cross-correlation coefficients) between the trunk muscles and upper trapezius for the abducted arm position during maximum trunk axial twist, while results for the latissimus dorsi-trunk pairings were more dependent on the specific trunk muscles (either abdominal or back) and latissimus dorsi muscle (either right or left side), as well as the range-of-motion movement. The findings of this study contribute to the understanding of interactions between the upper limbs and trunk, and highlight the influence of arm positions on the trunk musculature. In addition, the comparison of the present results to those of individuals with back or shoulder conditions may ultimately aid in elucidating underlying mechanisms or contributing factors to those conditions.

  2. Balance recovery is compromised and trunk muscle activity is increased in chronic obstructive pulmonary disease.

    PubMed

    Smith, Michelle D; Chang, Angela T; Hodges, Paul W

    2016-01-01

    Increased respiration in chronic obstructive pulmonary disease (COPD) requires greater abdominal muscle activation, which may impact on contribution of the trunk to postural control. This study aimed to determine whether recovery of balance from postural perturbations and trunk muscle activity differs in people with and without COPD before and/or after exercise. Electromyography (EMG) of the obliquus internus (OI) and externus (OE) abdominis, rectus abdominis (RA), erector spinae (ES) and deltoid muscles was recorded with surface electrodes during rapid shoulder flexion and extension. Time taken to regain baseline centre of pressure velocity (vCOP) and the number of postural adjustments following arm movement was calculated from force plate data. Time to recover balance in the direction of postural disturbance (anteroposterior vCOP) was longer in COPD, particularly more severe COPD, than controls. Mediolateral vCOP (perpendicular to the perturbation) and the number of postural adjustments did not differ between groups, but people with more severe COPD were less successful at returning their mediolateral vCOP to baseline. Abdominal muscle EMG was similar between groups, but controls had greater ES EMG during arm movements. Individuals with more severe COPD had greater OE and RA EMG both before and during arm movement compared to those with less severe COPD and controls. Following exercise, OE and ES EMG increased in people with less severe COPD. This study shows that severe COPD is associated with impaired ability to recover balance and greater trunk muscle activity during postural challenges. Augmented trunk muscle activity may limit the contribution of trunk movements to balance recovery and could contribute to increased falls risk.

  3. Human muscle spindle sensitivity reflects the balance of activity between antagonistic muscles.

    PubMed

    Dimitriou, Michael

    2014-10-08

    Muscle spindles are commonly considered as stretch receptors encoding movement, but the functional consequence of their efferent control has remained unclear. The "α-γ coactivation" hypothesis states that activity in a muscle is positively related to the output of its spindle afferents. However, in addition to the above, possible reciprocal inhibition of spindle controllers entails a negative relationship between contractile activity in one muscle and spindle afferent output from its antagonist. By recording spindle afferent responses from alert humans using microneurography, I show that spindle output does reflect antagonistic muscle balance. Specifically, regardless of identical kinematic profiles across active finger movements, stretch of the loaded antagonist muscle (i.e., extensor) was accompanied by increased afferent firing rates from this muscle compared with the baseline case of no constant external load. In contrast, spindle firing rates from the stretching antagonist were lowest when the agonist muscle powering movement (i.e., flexor) acted against an additional resistive load. Stepwise regressions confirmed that instantaneous velocity, extensor, and flexor muscle activity had a significant effect on spindle afferent responses, with flexor activity having a negative effect. Therefore, the results indicate that, as consequence of their efferent control, spindle sensitivity (gain) to muscle stretch reflects the balance of activity between antagonistic muscles rather than only the activity of the spindle-bearing muscle.

  4. Activation and intermuscular coherence of distal arm muscles during proximal muscle contraction.

    PubMed

    Lee, Sang Wook; Landers, Katlin; Harris-Love, Michelle L

    2014-03-01

    In the human upper extremity (UE), unintended effects of proximal muscle activation on muscles controlling the hand could be an important aspect of motor control due to the necessary coordination of distal and proximal segments during functional activities. This study aimed to elucidate the effects of concurrent activation of elbow muscles on the coordination between hand muscles performing a grip task. Eleven healthy subjects performed precision grip tasks while a constant extension or flexion moment was applied to their elbow joints, inducing a sustained submaximal contraction of elbow muscles to counter the applied torque. Activation of four hand muscles was measured during each task condition using surface electromyography (EMG). When concurrent activation of elbow muscles was induced, significant changes in the activation levels of the hand muscles were observed, with greater effects on the extrinsic finger extensor (23.2 % increase under 30 % elbow extensor activation; p = 0.003) than extrinsic finger flexor (14.2 % increase under 30 % elbow flexor activation; p = 0.130). Elbow muscle activation also induced involuntary changes in the intrinsic thumb flexor activation (44.6 % increase under 30 % elbow extensor activation; p = 0.005). EMG-EMG coherence analyses revealed that elbow muscle activation significantly reduced intermuscular coherence between distal muscle pairs, with its greatest effects on coherence in the β-band (13-25 Hz) (average of 17 % decrease under 30 % elbow flexor activation). The results of this study provide evidence for involuntary, muscle-specific interactions between distal and proximal UE muscles, which may contribute to UE motor performance in health and disease.

  5. Selective Activation of Shoulder, Trunk, and Arm Muscles: A Comparative Analysis of Different Push-Up Variants

    PubMed Central

    Marcolin, Giuseppe; Petrone, Nicola; Moro, Tatiana; Battaglia, Giuseppe; Bianco, Antonino; Paoli, Antonio

    2015-01-01

    Context The push-up is a widely used exercise for upper limb strengthening that can be performed with many variants. A comprehensive analysis of muscle activation during the ascendant phase (AP) and descendant phase (DP) in different variants could be useful for trainers and rehabilitators. Objective To obtain information on the effect of different push-up variants on the electromyography (EMG) of a large sample of upper limb muscles and to investigate the role of the trunk and abdomen muscles during the AP and DP. Design Cross-sectional study. Setting University laboratory. Patients or Other Participants Eight healthy, young volunteers without a history of upper extremity or spine injury. Intervention(s) Participants performed a set of 10 repetitions for each push-up variant: standard, wide, narrow, forward (FP), and backward (BP). Surface EMG of 12 selected muscles and kinematics data were synchronously recorded to describe the AP and DP. Main Outcome Measure(s) Mean EMG activity of the following muscles was analyzed: serratus anterior, deltoideus anterior, erector spinae, latissimus dorsi, rectus abdominis, triceps brachii caput longus, triceps brachii caput lateralis, obliquus externus abdominis, pectoralis major sternal head, pectoralis major clavicular head, trapezius transversalis, and biceps brachii. Results The triceps brachii and pectoralis major exhibited greater activation during the narrow-base variant. The highest activation of abdomen and back muscles was recorded for the FP and BP variants. The DP demonstrated the least electrical activity across all muscles, with less marked differences for the abdominal and erector spinae muscles because of their role as stabilizers. Conclusions Based on these findings, we suggest the narrow-base variant to emphasize triceps and pectoralis activity and the BP variant for total upper body strength conditioning. The FP and BP variants should be implemented carefully in participants with low back pain because of the

  6. Calcium uptake and bioelectrical activity of denervated and myotonic muscle

    PubMed Central

    Radu, H.; Gödri, I.; Albu, E.; Radu, A.; Robu, R.

    1970-01-01

    Calcium uptake on muscle microsomal fraction has been investigated in connection with bioelectrical activity in some muscle diseases. The findings showed a significant increase of calcium uptake in denervated muscle, which exhibited spontaneous bioelectrical activity (fibrillations). In myotonias, a low calcium uptake was peculiar to Steinert's disease but not to myotonia congenita. In other muscle diseases, such as progressive muscular dystrophy (Duchenne's type) or Charcot-Marie-Tooth's disease, the ability of muscle microsomal fraction to bind calcium was not changed. Starting with the key role of calcium in excitation-contraction coupling, the implications of calcium uptake disturbances in muscle electrogenesis are discussed. Images PMID:5431720

  7. Demonstrating Electrical Activity in Nerve and Muscle. Part II

    ERIC Educational Resources Information Center

    Robinson, D. J.

    1976-01-01

    Describes the construction of an amplifier and force transducer that can be used to demonstrate electrical activity in nerve and muscle using the gastrocnemius muscle and sciatic nerve of the frog. (MLH)

  8. Muscle activation of paraspinal muscles in different types of high heels during standing

    PubMed Central

    Han, Dongwook

    2015-01-01

    [Purpose] This study researched the effects of different types of high heels on the muscles surrounding the cervical spine, the thoracic spine, and the lumbar spine by analyzing muscle activation of the paraspinal muscles during standing while wearing high heels. The high heels were all of the same height: 8 cm. [Subjects and Methods] The 28 subjects in this experiment were females in their 20s with a foot size of 225–230 mm and a normal gait pattern. To measure the muscle activation of the paraspinal muscles, EMG electrodes were attached on the paraspinal muscles around C6, T7, and L5. The muscle activation during standing while wearing 8-cm-high wedge heels, setback heels, and French heels was then measured. The measurements were performed 3 times each, and the mean value was used for analysis. [Results] The levels of muscle activation of the paraspinal muscles induced by standing on wedge heels, setback heels, and French heels in the cervical and lumbar areas were significantly higher than those induced by standing on bare feet. But there was no significant difference according to the heel types. [Conclusion] The height of the heels presented a greater variable than the width of the heels on the muscle activation of paraspinal muscles. Therefore, wearing high heels is not recommended for those who have pain or functional problems in the cervical and/or lumbar spine. PMID:25642040

  9. Muscle activation of paraspinal muscles in different types of high heels during standing.

    PubMed

    Han, Dongwook

    2015-01-01

    [Purpose] This study researched the effects of different types of high heels on the muscles surrounding the cervical spine, the thoracic spine, and the lumbar spine by analyzing muscle activation of the paraspinal muscles during standing while wearing high heels. The high heels were all of the same height: 8 cm. [Subjects and Methods] The 28 subjects in this experiment were females in their 20s with a foot size of 225-230 mm and a normal gait pattern. To measure the muscle activation of the paraspinal muscles, EMG electrodes were attached on the paraspinal muscles around C6, T7, and L5. The muscle activation during standing while wearing 8-cm-high wedge heels, setback heels, and French heels was then measured. The measurements were performed 3 times each, and the mean value was used for analysis. [Results] The levels of muscle activation of the paraspinal muscles induced by standing on wedge heels, setback heels, and French heels in the cervical and lumbar areas were significantly higher than those induced by standing on bare feet. But there was no significant difference according to the heel types. [Conclusion] The height of the heels presented a greater variable than the width of the heels on the muscle activation of paraspinal muscles. Therefore, wearing high heels is not recommended for those who have pain or functional problems in the cervical and/or lumbar spine.

  10. ACTIVE STATE OF MUSCLE IN IODOACETATE RIGOR

    PubMed Central

    Mauriello, George E.; Sandow, Alexander

    1959-01-01

    Frog sartorius muscles, equilibrated to 2 x 10-4 M iodoacetic acid-Ringer's solution and activated by a series of twitches or a long tetanus, perform a rigor response consisting in general of a contractile change which plateaus and is then automatically reversed. Isotonic rigor shortening obeys a force-velocity relation which, with certain differences in value of the constants, accords with Hill's equation for this relation. Changes in rigidity during either isotonic or isometric rigor response show that the capacity of the rigor muscle to bear a load increases more abruptly than the corresponding onset of the ordinarily recorded response, briefly plateaus, and then decays. A quick release of about 1 mm. applied at any instant of isometric rigor output causes the tension to drop instantaneously to zero and then redevelop, the rate of redevelopment varying as does the intensity of the load-bearing capacity. These results demonstrate that rigor mechanical responses result from interaction of a passive, undamped series elastic component, and a contractile component with active state properties like those of normal contraction. Adenosinetriphosphate is known to break down in association with development of the rigor active state. This is discussed in relation to the apparent absence of ATP splitting in normal activation of the contractile component. PMID:13654738

  11. Stochastic modelling of muscle recruitment during activity

    PubMed Central

    Martelli, Saulo; Calvetti, Daniela; Somersalo, Erkki; Viceconti, Marco

    2015-01-01

    Muscle forces can be selected from a space of muscle recruitment strategies that produce stable motion and variable muscle and joint forces. However, current optimization methods provide only a single muscle recruitment strategy. We modelled the spectrum of muscle recruitment strategies while walking. The equilibrium equations at the joints, muscle constraints, static optimization solutions and 15-channel electromyography (EMG) recordings for seven walking cycles were taken from earlier studies. The spectrum of muscle forces was calculated using Bayesian statistics and Markov chain Monte Carlo (MCMC) methods, whereas EMG-driven muscle forces were calculated using EMG-driven modelling. We calculated the differences between the spectrum and EMG-driven muscle force for 1–15 input EMGs, and we identified the muscle strategy that best matched the recorded EMG pattern. The best-fit strategy, static optimization solution and EMG-driven force data were compared using correlation analysis. Possible and plausible muscle forces were defined as within physiological boundaries and within EMG boundaries. Possible muscle and joint forces were calculated by constraining the muscle forces between zero and the peak muscle force. Plausible muscle forces were constrained within six selected EMG boundaries. The spectrum to EMG-driven force difference increased from 40 to 108 N for 1–15 EMG inputs. The best-fit muscle strategy better described the EMG-driven pattern (R2 = 0.94; RMSE = 19 N) than the static optimization solution (R2 = 0.38; RMSE = 61 N). Possible forces for 27 of 34 muscles varied between zero and the peak muscle force, inducing a peak hip force of 11.3 body-weights. Plausible muscle forces closely matched the selected EMG patterns; no effect of the EMG constraint was observed on the remaining muscle force ranges. The model can be used to study alternative muscle recruitment strategies in both physiological and pathophysiological neuromotor conditions. PMID:25844155

  12. Defensive behaviour and biological activities of the abdominal secretion in the ant Crematogaster scutellaris (Hymenoptera: Myrmicinae).

    PubMed

    Marlier, J F; Quinet, Y; de Biseau, J C

    2004-11-30

    Using bioassays, the defensive behaviour of Crematogaster scutellaris and the biological activities of its abdominal secretion were investigated. Beside classical aggressive behaviours such as grips, C. scutellaris workers performed frequent characteristic gaster flexions during interspecific encounters, sometimes tempting to apply their abdominal secretion topically on the enemy. The toxicity of the venom of C. scutellaris to other ants greatly differed among the species tested, some being killed after the topical application of only three droplets, while others were quite resistant to a dose of 90 droplets. All ant species tested were strongly and immediately repelled by a contact between their antennae or mouthparts with the venom of C. scutellaris. Abdominal secretion was never used during intraspecific interference and workers were resistant to a topical application of the venom of their own species. Intraspecific repellency was significant but moderate compared to interspecific one. Workers of C. scutellaris were never seen using their venom during prey capture. In conclusion, the main biological activity of the abdominal secretion of C. scutellaris seems to be its repellency to other ant species. This is supported by field experiments showing that Pheidole pallidula foragers were efficiently repelled at coexploited baits, allowing the monopolization of most prey by C. scutellaris.

  13. Electrically and Hybrid-Induced Muscle Activations: Effects of Muscle Size and Fiber Type

    PubMed Central

    Stratton, Kelly; Faghri, Pouran D.

    2016-01-01

    The effect of three electrical stimulation (ES) frequencies (10, 35, and 50 Hz) on two muscle groups with different proportions of fast and slow twitch fibers (abductor pollicis brevis (APB) and vastus lateralis (VL)) was explored. We evaluated the acute muscles’ responses individually and during hybrid activations (ES superimposed by voluntary activations). Surface electromyography (sEMG) and force measurements were evaluated as outcomes. Ten healthy adults (mean age: 24.4 ± 2.5 years) participated after signing an informed consent form approved by the university Institutional Review Board. Protocols were developed to: 1) compare EMG activities during each frequency for each muscle when generating 25% Maximum Voluntary Contraction (MVC) force, and 2) compare EMG activities during each frequency when additional voluntary activation was superimposed over ES-induced 25% MVC to reach 50% and 75% MVC. Empirical mode decomposition (EMD) was utilized to separate ES artifacts from voluntary muscle activation. For both muscles, higher stimulation frequency (35 and 50Hz) induced higher electrical output detected at 25% of MVC, suggesting more recruitment with higher frequencies. Hybrid activation generated proportionally less electrical activity than ES alone. ES and voluntary activations appear to generate two different modes of muscle recruitment. ES may provoke muscle strength by activating more fatiguing fast acting fibers, but voluntary activation elicits more muscle coordination. Therefore, during the hybrid activation, less electrical activity may be detected due to recruitment of more fatigue-resistant deeper muscle fibers, not reachable by surface EMG. PMID:27990244

  14. Muscle motion and EMG activity in vibration treatment.

    PubMed

    Fratini, Antonio; La Gatta, Antonio; Bifulco, Paolo; Romano, Maria; Cesarelli, Mario

    2009-11-01

    The aim of this study is to highlight the relationship between muscle motion, generated by whole body vibration, and the correspondent electromyographic (EMG) activity and to suggest a new method to customize the stimulation frequency. Simultaneous recordings of EMG and tri-axial accelerations of quadriceps rectus femoris from fifteen subjects undergoing vibration treatments were collected. Vibrations were delivered via a sinusoidal oscillating platform at different frequencies (10-45 Hz). Muscle motion was estimated by processing the accelerometer data. Large EMG motion artifacts were removed using sharp notch filters centred at the vibration frequency and its superior harmonics. EMG-RMS values were computed and analyzed before and after artifact suppression to assess muscular activity. Muscles acceleration amplitude increased with frequency. Muscle displacements revealed a mechanical resonant-like behaviour of the muscle. Resonance frequencies and dumping factors depended on subject. Moreover, RMS of artifact-free EMG was found well correlated (R(2)=0.82) to the actual muscle displacement, while the maximum of the EMG response was found related to the mechanical resonance frequency of muscle. Results showed that maximum muscular activity was found in correspondence to the mechanical resonance of the muscle itself. Assuming the hypothesis that muscle activation is proportional to muscle displacement, treatment optimization (i.e. to choose the best stimulation frequency) could be obtained by simply monitoring local acceleration (resonance), leading to a more effective muscle stimulation. Motion artifact produced an overestimation of muscle activity, therefore its removal was essential.

  15. Trunk Muscle Activation at the Initiation and Braking of Bilateral Shoulder Flexion Movements of Different Amplitudes.

    PubMed

    Eriksson Crommert, M; Halvorsen, K; Ekblom, M M

    2015-01-01

    The aim of this study was to investigate if trunk muscle activation patterns during rapid bilateral shoulder flexions are affected by movement amplitude. Eleven healthy males performed shoulder flexion movements starting from a position with arms along sides (0°) to either 45°, 90° or 180°. EMG was measured bilaterally from transversus abdominis (TrA), obliquus internus (OI) with intra-muscular electrodes, and from rectus abdominis (RA), erector spinae (ES) and deltoideus with surface electrodes. 3D kinematics was recorded and inverse dynamics was used to calculate the reactive linear forces and torque about the shoulders and the linear and angular impulses. The sequencing of trunk muscle onsets at the initiation of arm movements was the same across movement amplitudes with ES as the first muscle activated, followed by TrA, RA and OI. All arm movements induced a flexion angular impulse about the shoulders during acceleration that was reversed during deceleration. Increased movement amplitude led to shortened onset latencies of the abdominal muscles and increased level of activation in TrA and ES. The activation magnitude of TrA was similar in acceleration and deceleration where the other muscles were specific to acceleration or deceleration. The findings show that arm movements need to be standardized when used as a method to evaluate trunk muscle activation patterns and that inclusion of the deceleration of the arms in the analysis allow the study of the relationship between trunk muscle activation and direction of perturbing torque during one and the same arm movement.

  16. Trunk Muscle Activation at the Initiation and Braking of Bilateral Shoulder Flexion Movements of Different Amplitudes

    PubMed Central

    Eriksson Crommert, M.; Halvorsen, K.; Ekblom, M. M.

    2015-01-01

    The aim of this study was to investigate if trunk muscle activation patterns during rapid bilateral shoulder flexions are affected by movement amplitude. Eleven healthy males performed shoulder flexion movements starting from a position with arms along sides (0°) to either 45°, 90° or 180°. EMG was measured bilaterally from transversus abdominis (TrA), obliquus internus (OI) with intra-muscular electrodes, and from rectus abdominis (RA), erector spinae (ES) and deltoideus with surface electrodes. 3D kinematics was recorded and inverse dynamics was used to calculate the reactive linear forces and torque about the shoulders and the linear and angular impulses. The sequencing of trunk muscle onsets at the initiation of arm movements was the same across movement amplitudes with ES as the first muscle activated, followed by TrA, RA and OI. All arm movements induced a flexion angular impulse about the shoulders during acceleration that was reversed during deceleration. Increased movement amplitude led to shortened onset latencies of the abdominal muscles and increased level of activation in TrA and ES. The activation magnitude of TrA was similar in acceleration and deceleration where the other muscles were specific to acceleration or deceleration. The findings show that arm movements need to be standardized when used as a method to evaluate trunk muscle activation patterns and that inclusion of the deceleration of the arms in the analysis allow the study of the relationship between trunk muscle activation and direction of perturbing torque during one and the same arm movement. PMID:26562017

  17. Graded Activation in Frog Muscle Fibers

    PubMed Central

    Costantin, L. L.; Taylor, S. R.

    1973-01-01

    The membrane potential of frog single muscle fibers in solutions containing tetrodotoxin was controlled with a two-electrode voltage clamp. Local contractions elicited by 100-ms square steps of depolarization were observed microscopically and recorded on cinefilm. The absence of myofibrillar folding with shortening to striation spacings below 1.95 µm served as a criterion for activation of the entire fiber cross section. With depolarizing steps of increasing magnitude, shortening occurred first in the most superficial myofibrils and spread inward to involve axial myofibrils as the depolarization was increased. In contractions in which the entire fiber cross section shortened actively, both the extent of shortening and the velocity of shortening at a given striation spacing could be graded by varying the magnitude of the depolarization step. The results provide evidence that the degree of activation of individual myofibrils can be graded with membrane depolarization. PMID:4540418

  18. Mean individual muscle activities and ratios of total muscle activities in a selective muscle strengthening experiment: the effects of lower limb muscle activity based on mediolateral slope angles during a one-leg stance

    PubMed Central

    Lee, Sang-Yeol

    2016-01-01

    [Purpose] The purpose of this study was to provide basic data for research on selective muscle strengthening by identifying mean muscle activities and calculating muscle ratios for use in developing strengthening methods. [Subjects and Methods] Twenty-one healthy volunteers were included in this study. Muscle activity was measured during a one-leg stance under 6 conditions of slope angle: 0°, 5°, 10°, 15°, 20°, and 25°. The data used in the analysis were root mean square and % total muscle activity values. [Results] There were significant differences in the root mean square of the gluteus medius, the hamstring, and the medial gastrocnemius muscles. There were significant differences in % total muscle activity of the medial gastrocnemius. [Conclusion] Future studies aimed at developing selective muscle strengthening methods are likely to yield more effective results by using muscle activity ratios based on electromyography data. PMID:27799690

  19. In vitro activity of moxifloxacin against 923 anaerobes isolated from human intra-abdominal infections.

    PubMed

    Goldstein, Ellie J C; Citron, Diane M; Warren, Yumi A; Tyrrell, Kerin L; Merriam, C Vreni; Fernandez, Helen

    2006-01-01

    The in vitro activity of moxifloxacin against 923 recent anaerobic isolates obtained from pretreatment cultures in patients with complicated intra-abdominal infections was studied using the CLSI M11-A-6 agar dilution method. Moxifloxacin was active against 87% (96 of 110) Bacteroides fragilis strains at < or = 1 microg/ml and 87% (79 of 90) B. thetaiotaomicron strains at < or = 2 microg/ml. Species variation was seen, with B. uniformis, B. vulgatus, Clostridium clostridioforme, and C. symbiosum being least susceptible and accounting for most of the resistant isolates; excluding the aforementioned four resistant species, 86% (303 of 363) of Bacteroides species isolates and 94% (417 of 450) of all other genera and species were susceptible to < or = 2 microg/ml of moxifloxacin. Overall, moxifloxacin was active against 763 of 923 (83%) of strains at < or = 2 microg/ml, supporting its use as a monotherapy for some community-acquired intra-abdominal infections.

  20. Abdominal wall surgery

    MedlinePlus

    ... the results of abdominoplasty. Many feel a new sense of self-confidence. Alternative Names Cosmetic surgery of the abdomen; Tummy tuck; Abdominoplasty Images Abdominoplasty - series Abdominal muscles References McGrath MH, Pomerantz J. Plastic surgery. In: Townsend ...

  1. Functional characteristics of the rat jaw muscles: daily muscle activity and fiber type composition.

    PubMed

    Kawai, Nobuhiko; Sano, Ryota; Korfage, Joannes A M; Nakamura, Saika; Tanaka, Eiji; van Wessel, Tim; Langenbach, Geerling E J; Tanne, Kazuo

    2009-12-01

    Skeletal muscles have a heterogeneous fiber type composition, which reflects their functional demand. The daily muscle use and the percentage of slow-type fibers have been shown to be positively correlated in skeletal muscles of larger animals but for smaller animals there is no information. The examination of this relationship in adult rats was the purpose of this study. We hypothesized a positive relationship between the percentage of fatigue-resistant fibers in each muscle and its total duration of use per day. Fourteen Wistar strain male rats (410-450 g) were used. A radio-telemetric device was implanted to record muscle activity continuously from the superficial masseter, deep 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) exceeding specified levels of the peak activity (2, 5, 20 and 50%). The fiber type composition of the muscles was examined by the myosin heavy chain content of the fibers by means of immunohistochemical staining. At lower activity levels (exceeding 2 and 5% of the peak activity), the duty time of the anterior belly of digastric muscle was significantly (P < 0.01) longer than those of the other muscles. The anterior belly of digastric muscle also contained the highest percentage of slow-type fibers (type I fiber and hybrid fiber co-expressing myosin heavy chain I + IIA) (ca. 11%; P < 0.05). By regression analysis for all four muscles, an inter-muscular comparison showed a positive relationship between the duty time (exceeding 50% of the peak activity) and the percentage of type IIX fibers (P < 0.05), which demonstrate intermediate physiological properties relative to type IIA and IIB fibers. For the jaw muscles of adult male rats, the variations of fiber type composition and muscle use suggest that the muscle containing the largest amounts of slow-type fibers (the anterior belly of digastric muscle) is mainly

  2. Alternate-Day High-Fat Diet Induces an Increase in Mitochondrial Enzyme Activities and Protein Content in Rat Skeletal Muscle.

    PubMed

    Li, Xi; Higashida, Kazuhiko; Kawamura, Takuji; Higuchi, Mitsuru

    2016-04-06

    Long-term high-fat diet increases muscle mitochondrial enzyme activity and endurance performance. However, excessive calorie intake causes intra-abdominal fat accumulation and metabolic syndrome. The purpose of this study was to investigate the effect of an alternating day high-fat diet on muscle mitochondrial enzyme activities, protein content, and intra-abdominal fat mass in rats. Male Wistar rats were given a standard chow diet (CON), high-fat diet (HFD), or alternate-day high-fat diet (ALT) for 4 weeks. Rats in the ALT group were fed a high-fat diet and standard chow every other day for 4 weeks. After the dietary intervention, mitochondrial enzyme activities and protein content in skeletal muscle were measured. Although body weight did not differ among groups, the epididymal fat mass in the HFD group was higher than those of the CON and ALT groups. Citrate synthase and beta-hydroxyacyl CoA dehydrogenase activities in the plantaris muscle of rats in HFD and ALT were significantly higher than that in CON rats, whereas there was no difference between HFD and ALT groups. No significant difference was observed in muscle glycogen concentration or glucose transporter-4 protein content among the three groups. These results suggest that an alternate-day high-fat diet induces increases in mitochondrial enzyme activities and protein content in rat skeletal muscle without intra-abdominal fat accumulation.

  3. Alternate-Day High-Fat Diet Induces an Increase in Mitochondrial Enzyme Activities and Protein Content in Rat Skeletal Muscle

    PubMed Central

    Li, Xi; Higashida, Kazuhiko; Kawamura, Takuji; Higuchi, Mitsuru

    2016-01-01

    Long-term high-fat diet increases muscle mitochondrial enzyme activity and endurance performance. However, excessive calorie intake causes intra-abdominal fat accumulation and metabolic syndrome. The purpose of this study was to investigate the effect of an alternating day high-fat diet on muscle mitochondrial enzyme activities, protein content, and intra-abdominal fat mass in rats. Male Wistar rats were given a standard chow diet (CON), high-fat diet (HFD), or alternate-day high-fat diet (ALT) for 4 weeks. Rats in the ALT group were fed a high-fat diet and standard chow every other day for 4 weeks. After the dietary intervention, mitochondrial enzyme activities and protein content in skeletal muscle were measured. Although body weight did not differ among groups, the epididymal fat mass in the HFD group was higher than those of the CON and ALT groups. Citrate synthase and beta-hydroxyacyl CoA dehydrogenase activities in the plantaris muscle of rats in HFD and ALT were significantly higher than that in CON rats, whereas there was no difference between HFD and ALT groups. No significant difference was observed in muscle glycogen concentration or glucose transporter-4 protein content among the three groups. These results suggest that an alternate-day high-fat diet induces increases in mitochondrial enzyme activities and protein content in rat skeletal muscle without intra-abdominal fat accumulation. PMID:27058555

  4. Muscular Activity and Fatigue in Lower-Limb and Trunk Muscles during Different Sit-To-Stand Tests

    PubMed Central

    Roldán-Jiménez, Cristina; Bennett, Paul; Cuesta-Vargas, Antonio I.

    2015-01-01

    Sit-to-stand (STS) tests measure the ability to get up from a chair, reproducing an important component of daily living activity. As this functional task is essential for human independence, STS performance has been studied in the past decades using several methods, including electromyography. The aim of this study was to measure muscular activity and fatigue during different repetitions and speeds of STS tasks using surface electromyography in lower-limb and trunk muscles. This cross-sectional study recruited 30 healthy young adults. Average muscle activation, percentage of maximum voluntary contraction, muscle involvement in motion and fatigue were measured using surface electrodes placed on the medial gastrocnemius (MG), biceps femoris (BF), vastus medialis of the quadriceps (QM), the abdominal rectus (AR), erector spinae (ES), rectus femoris (RF), soleus (SO) and the tibialis anterior (TA). Five-repetition STS, 10-repetition STS and 30-second STS variants were performed. MG, BF, QM, ES and RF muscles showed differences in muscle activation, while QM, AR and ES muscles showed significant differences in MVC percentage. Also, significant differences in fatigue were found in QM muscle between different STS tests. There was no statistically significant fatigue in the BF, MG and SO muscles of the leg although there appeared to be a trend of increasing fatigue. These results could be useful in describing the functional movements of the STS test used in rehabilitation programs, notwithstanding that they were measured in healthy young subjects. PMID:26506612

  5. The influence of experimentally induced pain on shoulder muscle activity.

    PubMed

    Diederichsen, Louise Pyndt; Winther, Annika; Dyhre-Poulsen, Poul; Krogsgaard, Michael R; Nørregaard, Jesper

    2009-04-01

    Muscle function is altered in painful shoulder conditions. However, the influence of shoulder pain on muscle coordination of the shoulder has not been fully clarified. The aim of the present study was to examine the effect of experimentally induced shoulder pain on shoulder muscle function. Eleven healthy men (range 22-27 years), with no history of shoulder or cervical problems, were included in the study. Pain was induced by 5% hypertonic saline injections into the supraspinatus muscle or subacromially. Seated in a shoulder machine, subjects performed standardized concentric abduction (0 degrees -105 degrees) at a speed of approximately 120 degrees/s, controlled by a metronome. During abduction, electromyographic (EMG) activity was recorded by intramuscular wire electrodes inserted in two deeply located shoulder muscles and by surface-electrodes over six superficially located shoulder muscles. EMG was recorded before pain, during pain and after pain had subsided and pain intensity was continuously scored on a visual analog scale (VAS). During abduction, experimentally induced pain in the supraspinatus muscle caused a significant decrease in activity of the anterior deltoid, upper trapezius and the infraspinatus and an increase in activity of lower trapezius and latissimus dorsi muscles. Following subacromial injection a significantly increased muscle activity was seen in the lower trapezius, the serratus anterior and the latissimus dorsi muscles. In conclusion, this study shows that acute pain both subacromially and in the supraspinatus muscle modulates coordination of the shoulder muscles during voluntary movements. During painful conditions, an increased activity was detected in the antagonist (latissimus), which support the idea that localized pain affects muscle activation in a way that protects the painful structure. Further, the changes in muscle activity following subacromial pain induction tend to expand the subacromial space and thereby decrease the load

  6. [Secretory activity of the stomach during modeling of increased filling of abdominal veins].

    PubMed

    Afonin, B V; Goncharova, N P

    2009-01-01

    Determination of the stomach secretory activity and ultrasonic investigation of the gastroduodenal organs and vessels were performed in test-subjects tilted at -12 degrees and -15 degrees. Short HDT(12-24 hrs.) as a hypokinesia factor was minimized which caused enlargement of the parenchymatous and thickening of walls of the hollow organs. Increased filling of the abdominal veins was paralleled by rise in pepsinogen levels in blood and urine, and increase in the intravitelline content in fasting subjects. Elevated tone of the pylorus and retarded evacuation from the stomach indicated active hydrochloric acid secretion. Concurrently, bile and pancreas juices were secreted more profusely and intestinal content in the duodenum increased. It was shown that modeled increase of abdominal vein filling stimulates secretion as by fasting stomach so by the liver and pancreas.

  7. Ultrasound assessment of transversus abdominis muscle contraction ratio during abdominal hollowing: a useful tool to distinguish between patients with chronic low back pain and healthy controls?

    PubMed

    Pulkovski, N; Mannion, A F; Caporaso, F; Toma, V; Gubler, D; Helbling, D; Sprott, H

    2012-08-01

    Spine stabilisation exercises, in which patients are taught to preferentially activate the transversus abdominus (TrA) during "abdominal hollowing" (AH), are a popular treatment for chronic low back pain (cLBP). The present study investigated whether performance during AH differed between cLBP patients and controls to an extent that would render it useful diagnostic tool. 50 patients with cLBP (46.3 ± 12.5 years) and 50 healthy controls (43.6 ± 12.7 years) participated in this case-control study. They performed AH in hook-lying. Using M-mode ultrasound, thicknesses of TrA, and obliquus internus and externus were determined at rest and during 5 s AH (5 measures each body side). The TrA contraction-ratio (TrA-CR) (TrA contracted/rest) and the ability to sustain the contraction [standard deviation (SD) of TrA thickness during the stable phase of the hold] were investigated. There were no significant group differences for the absolute muscle thicknesses at rest or during AH, or for the SD of TrA thickness. There was a small but significant difference between the groups for TrA-CR: cLBP 1.35 ± 0.14, controls 1.44 ± 0.24 (p < 0.05). However, Receiver Operator Characteristics (ROC) analysis revealed a poor and non-significant ability of TrA-CR to discriminate between cLBP patients and controls on an individual basis (ROC area under the curve, 0.60 [95% CI 0.495; 0.695], p = 0.08). In the patient group, TrA-CR showed a low but significant correlation with Roland Morris score (Spearman Rho = 0.328; p = 0.02). In conclusion, the difference in group mean values for TrA-CR was small and of uncertain clinical relevance. Moreover, TrA-CR showed a poor ability to discriminate between control and cLBP subjects on an individual basis. We conclude that the TrA-CR during abdominal hollowing does not distinguish well between patients with chronic low back pain and healthy controls.

  8. Muscle metaboreceptor modulation of cutaneous active vasodilation

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.; Stephens, D. P.; Johnson, J. M.

    1998-01-01

    PURPOSE: Isometric handgrip exercise in hyperthermia has been shown to reduce cutaneous vascular conductance (CVC) by inhibiting the cutaneous active vasodilator system. METHODS: To identify whether this response was initiated by muscle metaboreceptors, in seven subjects two 3-min bouts of isometric handgrip exercise in hyperthermia were performed, followed by 2 min of postexercise ischemia (PEI). An index of forearm skin blood flow (laser-Doppler flowmetry) was measured on the contralateral arm at an unblocked site and at a site at which adrenergic vasoconstrictor function was blocked via bretylium iontophoresis to reveal active cutaneous vasodilator function unambiguously. Sweat rate was measured via capacitance hygrometry, CVC was indexed from the ratio of skin blood flow to mean arterial pressure and was expressed as a percentage of maximal CVC at that site. In normothermia, neither isometric exercise nor PEI affected CVC (P > 0.05). RESULTS: The first bout of isometric handgrip exercise in hyperthermia reduced CVC at control sites and this reduction persisted through PEI (pre-exercise: 59.8 +/- 5.4, exercise: 49.8 +/- 4.9, PEI: 49.7 +/- 5.3% of maximum; both P < 0.05), whereas there were no significant changes in CVC at the bretylium treated sites. The succeeding bout of isometric exercise in hyperthermia significantly reduced CVC at both untreated (pre-exercise: 59.0 +/- 4.8, exercise: 47.3 +/- 4.0, PEI: 50.1 +/- 4.1% of maximum; both P < 0.05) and bretylium treated sites (pre-exercise: 61.4 +/- 7.3, exercise: 50.6 +/- 5.1, PEI: 53.9 +/- 6.0% of maximum, both P < 0.05). At both sites, CVC during PEI was lower than during the pre-exercise period (P < 0.05). Sweat rate rose significantly during both bouts of isometric exercise and remained elevated during PEI. CONCLUSIONS: These data suggest that the reduction in CVC during isometric exercise in hyperthermia, including the inhibition of the active vasodilator system, is primarily mediated by muscle

  9. The effects of aquatic trunk exercise on gait and muscle activity in stroke patients: a randomized controlled pilot study.

    PubMed

    Park, Byoung-Sun; Noh, Ji-Woong; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Park, Jaehong; Kim, Junghwan

    2015-11-01

    [Purpose] The purpose of this study was to investigate the relationship between muscle activity and gait function following aquatic trunk exercise in hemiplegic stroke patients. [Subjects and Methods] This study's participants included thirteen hemiplegic patients (ten males and three females). The aquatic therapy consisted of administering concentrative aquatic therapy for four weeks in a therapeutic pool. Gait parameters were measured using a gait analysis system adjusted to each subject's comfortable walking speed. Electromyographic signals were measured for the rectus abdominis, external abdominal oblique, transversus abdominis/internal-abdominal oblique, and erector spine of each patients. [Results] The pre- and post-training performances of the transversus abdominis/internal-abdominal oblique were compared statistically. There was no statistical difference between the patients' pre- and post-training values of maximal voluntary isometric contraction of the rectus abdominis, but the external abdominal oblique values tended to improve. Furthermore, gait factors improved significantly in terms of walking speeds, walking cycles, affected-side stance phases, affected-stride lengths, and stance-phase symmetry indices, respectively. [Conclusion] These results suggest that the trunk exercise during aquatic therapy may in part contribute to clinically relevant improvements in muscle activities and gait parameters.

  10. Relative activity of respiratory muscles during prescribed inspiratory muscle training in healthy people.

    PubMed

    Jung, Ju-Hyeon; Kim, Nan-Soo

    2016-03-01

    [Purpose] This study aimed to determine the effects of different intensities of inspiratory muscle training on the relative respiratory muscle activity in healthy adults. [Subjects and Methods] Thirteen healthy male volunteers were instructed to perform inspiratory muscle training (0%, 40%, 60%, and 80% maximal inspiratory pressure) on the basis of their individual intensities. The inspiratory muscle training was performed in random order of intensities. Surface electromyography data were collected from the right-side diaphragm, external intercostal, and sternocleidomastoid, and pulmonary functions (forced expiratory volume in 1 s, forced vital capacity, and their ratio; peak expiratory flow; and maximal inspiratory pressure) were measured. [Results] Comparison of the relative activity of the diaphragm showed significant differences between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. Furthermore, significant differences were found in sternocleidomastoid relative activity between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. [Conclusion] During inspiratory muscle training in the clinic, the patients were assisted (verbally or through feedback) by therapists to avoid overactivation of their accessory muscles (sternocleidomastoid). This study recommends that inspiratory muscle training be performed at an accurate and appropriate intensity through the practice of proper deep breathing.

  11. Relative activity of respiratory muscles during prescribed inspiratory muscle training in healthy people

    PubMed Central

    Jung, Ju-hyeon; Kim, Nan-soo

    2016-01-01

    [Purpose] This study aimed to determine the effects of different intensities of inspiratory muscle training on the relative respiratory muscle activity in healthy adults. [Subjects and Methods] Thirteen healthy male volunteers were instructed to perform inspiratory muscle training (0%, 40%, 60%, and 80% maximal inspiratory pressure) on the basis of their individual intensities. The inspiratory muscle training was performed in random order of intensities. Surface electromyography data were collected from the right-side diaphragm, external intercostal, and sternocleidomastoid, and pulmonary functions (forced expiratory volume in 1 s, forced vital capacity, and their ratio; peak expiratory flow; and maximal inspiratory pressure) were measured. [Results] Comparison of the relative activity of the diaphragm showed significant differences between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. Furthermore, significant differences were found in sternocleidomastoid relative activity between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. [Conclusion] During inspiratory muscle training in the clinic, the patients were assisted (verbally or through feedback) by therapists to avoid overactivation of their accessory muscles (sternocleidomastoid). This study recommends that inspiratory muscle training be performed at an accurate and appropriate intensity through the practice of proper deep breathing. PMID:27134409

  12. The effects of visual biofeedback using ultrasonograpy on deep trunk muscle activation

    PubMed Central

    Cha, Hyun-Gyu; Kim, Myoung-Kwon; Shin, Young-Jun

    2016-01-01

    [Purpose] The objective of this study is to investigate the effect of visual biofeedback using ulatrasonography on the functional improvement of deep trunk muscle. [Subjects and Methods] This study selected ten healthy people without orthopedic history and information on the study. The average ages, heights, and weights were 22.70 ± 2.06 years old, 171.15 ± 9.18 cm, and 66.86 ± 8.88 kg in the experimental group, respectively. The abdominal drawing-in maneuver were executed for subjects through monitoring the status of muscle contraction using ultrasonic waves. And motor control exercises were performed during 6 weeks, 20 minutes/day and three times/week. We collected the data using electromyography MP150 system (BIOPAC system Inc., CA, USA) in order to measure trunk muscle activation. [Results] The subjects showed significant improvements in Internal oblique abdominis and lumbar multifidus muscle after intervention. [Conclusion] Visual biofeedback training using ultrasonography might be effective in improving function of the deep trunk muscle. PMID:28174441

  13. Seasonal variation in muscle sympathetic nerve activity

    PubMed Central

    Cui, Jian; Muller, Matthew D; Blaha, Cheryl; Kunselman, Allen R; Sinoway, Lawrence I

    2015-01-01

    Epidemiologic data suggest there are seasonal variations in the incidence of severe cardiac events with peak levels being evident in the winter. Whether autonomic indices including muscle sympathetic nerve activity (MSNA) vary with season remains unclear. In this report, we tested the hypothesis that resting MSNA varies with the seasons of the year with peak levels evident in the winter. We analyzed the supine resting MSNA in 60 healthy subjects. Each subject was studied during two, three, or four seasons (total 237 visits). MSNA burst rate in the winter (21.0 ± 6.8 burst/min, mean ± SD) was significantly greater than in the summer (13.5 ± 5.8 burst/min, P < 0.001), the spring (17.1 ± 9.0 burst/min, P = 0.03), and the fall (17.9 ± 7.7 burst/min, P = 0.002). There was no significant difference in MSNA for other seasonal comparisons. The results suggest that resting sympathetic nerve activity varies along the seasons, with peak levels evident in the winter. We speculate that the seasonal changes in sympathetic activity may be a contribution to the previously observed seasonal variations in cardiovascular morbidity and mortality. PMID:26265752

  14. Regionalizing muscle activity causes changes to the magnitude and direction of the force from whole muscles-a modeling study.

    PubMed

    Rahemi, Hadi; Nigam, Nilima; Wakeling, James M

    2014-01-01

    Skeletal muscle can contain neuromuscular compartments that are spatially distinct regions that can receive relatively independent levels of activation. This study tested how the magnitude and direction of the force developed by a whole muscle would change when the muscle activity was regionalized within the muscle. A 3D finite element model of a muscle with its bounding aponeurosis was developed for the lateral gastrocnemius, and isometric contractions were simulated for a series of conditions with either a uniform activation pattern, or regionally distinct activation patterns: in all cases the mean activation from all fibers within the muscle reached 10%. The models showed emergent features of the fiber geometry that matched physiological characteristics: with fibers shortening, rotating to greater pennation, adopting curved trajectories in 3D and changes in the thickness and width of the muscle belly. Simulations were repeated for muscle with compliant, normal and stiff aponeurosis and the aponeurosis stiffness affected the changes to the fiber geometry and the resultant muscle force. Changing the regionalization of the activity resulted to changes in the magnitude, direction and center of the force vector from the whole muscle. Regionalizing the muscle activity resulted in greater muscle force than the simulation with uniform activity across the muscle belly. The study shows how the force from a muscle depends on the complex interactions between the muscle fibers and connective tissues and the region of muscle that is active.

  15. Muscle activation patterns when passively stretching spastic lower limb muscles of children with cerebral palsy.

    PubMed

    Bar-On, Lynn; Aertbeliën, Erwin; Molenaers, Guy; Desloovere, Kaat

    2014-01-01

    The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP) these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.8 ± 3.8 yrs; bilateral/unilateral involvement n =  32/22; Gross Motor Functional Classification Score I-IV) of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG) from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG) compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle- and subject-specific (p<0.01). The intra-rater reliability of all quantitative parameters was moderate to good. Comparing RMS-EMG between incremental position

  16. a Dynamical Model of Muscle Activation, Fatigue and Recovery

    NASA Astrophysics Data System (ADS)

    Liu, Jing Z.; Yue, Guang H.; Brown, Robert W.

    2001-04-01

    A dynamical model on muscle activation, fatigue, and recovery was developed to provide a theoretical framework for explaining the force produced by muscle(s) during the process of getting activated and fatigued. By simplifying the fatigue effect and the recovery effect as two phenomenological parameters (F, R), we developed a set of dynamical equations to describe the behavior of muscle(s) as a group of motor units under an external drive, e.g., voluntary brain effort. This model provides a macroscopic view for understanding the biophysical mechanisms of voluntary drive, fatigue effect, and recovery in stimulating, limiting and modulating the force output from muscle(s). Agreement between the experimental data and the predicted forces is excellent. This model may also generate new possibilities in clinical and engineering applications. The parameters introduced by this model can serve as good indicators of physical conditions, and may be useful for quantitative diagnosis of certain diseases related to muscles, especially symptoms of fatigue. Inference from the model can clarify a long-debating question regarding the maximal possibility of muscle force production. It can also be used as guideline for simulating real muscle in muscle engineering or design of human-mimic robot.

  17. Neck muscle activity in skydivers during parachute opening shock.

    PubMed

    Lo Martire, R; Gladh, K; Westman, A; Lindholm, P; Nilsson, J; Äng, B O

    2016-03-01

    This observational study investigated skydiver neck muscle activity during parachute opening shock (POS), as epidemiological data recently suggested neck pain in skydivers to be related to POS. Twenty experienced skydivers performed two terminal velocity skydives each. Surface electromyography quantified muscle activity bilaterally from the anterior neck, the upper and lower posterior neck, and the upper shoulders; and two triaxial accelerometers sampled deceleration. Muscle activity was normalized as the percentage of reference maximum voluntary electrical activity (% MVE); and temporal muscle activity onset was related to POS onset. Our results showed that neck muscle activity during POS reached mean magnitudes of 53-104% MVE, often exceeding reference activity in the lower posterior neck and upper shoulders. All investigated muscle areas' mean temporal onsets occurred <50 ms after POS onset (9-34 ms latencies), which is consistent with anticipatory motor control. The high muscle activity observed supports that the neck is under substantial strain during POS, while temporal muscle activation suggests anticipatory motor control to be a strategy used by skydivers to protect the cervical spine from POS. This study's findings contribute to understanding the high rates of POS-related neck pain, and further support the need for evaluation of neck pain preventative strategies.

  18. Comparison between muscle activation measured by electromyography and muscle thickness measured using ultrasonography for effective muscle assessment.

    PubMed

    Kim, Chang-Yong; Choi, Jong-Duk; Kim, Suhn-Yeop; Oh, Duck-Won; Kim, Jin-Kyung; Park, Ji-Whan

    2014-10-01

    In this study, we aimed to compare the intrarater reliability and validity of muscle thickness measured using ultrasonography (US) and muscle activity via electromyography (EMG) during manual muscle testing (MMT) of the external oblique (EO) and lumbar multifidus (MF) muscles. The study subjects were 30 healthy individuals who underwent MMT at different grades. EMG was used to measure the muscle activity in terms of ratio to maximum voluntary contraction (MVC) and root mean square (RMS) metrics. US was used to measure the raw muscle thickness, the ratio of muscle thickness at MVC, and the ratio of muscle thickness at rest. One examiner performed measurements on each subject in 3 trials. The intrarater reliabilities of the % MVC RMS and raw RMS metrics for EMG and the % MVC thickness metrics for US were excellent (ICC=0.81-0.98). There was a significant difference between all the grades measured using the % MVC thickness metric (p<0.01). Further, this % MVC thickness metric of US showed a significantly higher correlation with the EMG measurement methods than with the others (r=0.51-0.61). Our findings suggest that the % MVC thickness determined by US was the most sensitive of all methods for assessing the MMT grade.

  19. Does breathing type influence electromyographic activity of obligatory and accessory respiratory muscles?

    PubMed

    Gutiérrez, M F; Valenzuela, S; Miralles, R; Portus, C; Santander, H; Fuentes, A D; Celhay, I

    2014-11-01

    Craniomandibular electromyographic (EMG) studies frequently include several parameters, e.g. resting, chewing and tooth-clenching. EMG activity during these parameters has been recorded in the elevator muscles, but little is known about the respiratory muscles. The aim of this study was to compare EMG activity in obligatory and accessory respiratory muscles between subjects with different breathing types. Forty male subjects were classified according to their breathing type into two groups of 20 each: costo-diaphragmatic breathing type and upper costal breathing type. Bipolar surface electrodes were placed on the sternocleidomastoid, diaphragm, external intercostal and latissimus dorsi muscles. EMG activity was recorded during the following tasks: (i) normal quiet breathing, (ii) maximal voluntary clenching in intercuspal position, (iii) natural rate chewing until swallowing threshold, (iv) short-time chewing. Diaphragm EMG activity was significantly higher in the upper costal breathing type than in the costo-diaphragmatic breathing type in all tasks (P < 0·05). External intercostal EMG activity was significantly higher in the upper costal breathing type than in the costo-diaphragmatic breathing type in tasks 3 and 4 (P < 0·05). Sternocleidomastoid and latissimus dorsi EMG activity did not show significant differences between breathing types in the tasks studied (P > 0·05). The significantly higher EMG activity observed in subjects with upper costal breathing than in the costo-diaphragmatic breathing type suggests that there could be differences in motor unit recruitment strategies depending on the breathing type. This may be an expression of the adaptive capability of muscle chains in subjects who clinically have a different thoraco-abdominal expansion during inspiration at rest.

  20. Motion and Muscle Activity Are Affected by Instability Location During a Squat Exercise.

    PubMed

    Nairn, Brian C; Sutherland, Chad A; Drake, Janessa D M

    2017-03-01

    Nairn, BC, Sutherland, CA, and Drake, JDM. Motion and muscle activity are affected by instability location during a squat exercise. J Strength Cond Res 31(3): 677-685, 2017-Squat exercise training using instability devices has become increasingly popular for a multitude of reasons. Many devices generate instability at the feet and provide a bottom-up perturbation; however, the effect of a top-down instability device during a squat remains unclear. To induce instability at the upper body, a water-filled cylinder called the Attitube was used. This study analyzed the effects of instability location (top-down, bottom-up, and no instability) during a squat exercise in terms of kinematics and muscle activation. Ten male participants were instrumented with 75 reflective markers to track kinematics of the ankle, knee, hip, trunk, and the Bar/Attitube, and electromyography was recorded from 12 muscles bilaterally. Squats were performed with an Olympic bar on a stable surface, an Olympic bar on a BOSU ball (BALL, bottom-up), and the Attitube on solid ground (TUBE, top-down). The TUBE showed up to 1.5 times reduction in erector spinae activation and up to 1.5 times less trunk flexion while being performed at a slower velocity. There was also higher abdominal activation in the TUBE, with up to 2.8 times greater oblique activation compared with the stable condition. The BALL increased ankle eversion and knee flexion with higher muscle activation in gastrocnemius, biceps femoris, and quadriceps. Overall, changing the location of instability during a squat changed the motion and muscle activation patterns of the trunk and lower extremities. This provides information for future research into rehabilitation, learning proper squat technique, and for specific training scenarios.

  1. Independent Active Contraction of Extraocular Muscle Compartments

    PubMed Central

    Shin, Andrew; Yoo, Lawrence; Demer, Joseph L.

    2015-01-01

    Purpose. Intramuscular innervation of horizontal rectus extraocular muscle (EOMs) is segregated into superior and inferior (transverse) compartments, whereas all EOMs are also divided into global (GL) and orbital (OL) layers with scleral and pulley insertions, respectively. Mechanical independence between both types of compartments has been demonstrated during passive tensile loading. We examined coupling between EOM compartments during active, ex vivo contraction. Methods. Fresh bovine EOMs were removed, and one compartment of each was coated with hydrophobic petrolatum. Contraction of the uncoated compartment was induced by immersion in a solution of 50 mM CaCl2 at 38°C labeled with sodium fluorescein dye, whereas tensions in both compartments were monitored by strain gauges. Control experiments omitted petrolatum so that the entire EOM contracted. After physiological experiments, EOMs were sectioned transversely to demonstrate specificity of CaCl2 permeation by yellow fluorescence dye excited by blue light. Results. In control experiments without petrolatum, both transverse and GL and OL compartments contracted similarly. Selective compartmental omission of petrolatum caused markedly independent compartmental contraction whether measured at the GL or the OL insertions or for transverse compartments at the scleral insertion. Although some CaCl2 spread occurred, mean (±SD) tension in the coated compartments averaged only 10.5 ± 3.3% and 6.0 ± 1.5% in GL/OL and transverse compartments, respectively relative to uncoated compartments. Fluorescein penetration confirmed selective CaCl2 permeation. Conclusions. These data confirm passive tensile findings of mechanical independence of EOM compartments and extend results to active contraction. EOMs behave actively as if composed of mechanically independent parallel fiber bundles having different insertional targets, consistent with the active pulley and transverse compartmental hypotheses. PMID:25503460

  2. Synaptic activity and connective tissue remodeling in denervated frog muscle

    PubMed Central

    1994-01-01

    Denervation of skeletal muscle results in dramatic remodeling of the cellular and molecular composition of the muscle connective tissue. This remodeling is concentrated in muscle near neuromuscular junctions and involves the accumulation of interstitial cells and several extracellular matrix molecules. Given the role of extracellular matrix in neurite outgrowth and synaptogenesis, we predict that this remodeling of the junctional connective tissue directly influences the regeneration of the neuromuscular junction. As one step toward understanding the role of this denervation-induced remodeling in synapse formation, we have begun to look for the signals that are involved in initiating the junctional accumulations of interstitial cells and matrix molecules. Here, the role of muscle inactivity as a signal was examined. The distributions of interstitial cells, fibronectin, and tenascin were determined in muscles inactivated by presynaptic blockade of muscle activity with tetrodotoxin. We found that blockade of muscle activity for up to 4 wk produced neither the junctional accumulation of interstitial cells nor the junctional concentrations of tenascin and fibronectin normally present in denervated frog muscle. In contrast, the muscle inactivity induced the extrajunctional appearance of two synapse-specific molecules, the acetylcholine receptor and a muscle fiber antigen, mAb 3B6. These results demonstrate that the remodeling of the junctional connective tissue in response to nerve injury is a unique response of muscle to denervation in that it is initiated by a mechanism that is independent of muscle activity. Thus connective tissue remodeling in denervated skeletal muscle may be induced by signals released from or associated with the nerve other than the evoked release of neurotransmitter. PMID:7525607

  3. The effects of upper extremity task training with symmetric abdominal muscle contraction on trunk stability and balance in chronic stroke patients

    PubMed Central

    Lee, Je-hyeok; Choi, Jong-duk

    2017-01-01

    [Purpose] The purpose of this study is to examine the effects of upper extremity task training employing the bracing method on the trunk control and balance of stroke patients. [Subjects and Methods] The subjects were 46 stroke patients whose strokes had occurred six months or more prior to the study. The subjects were divided into two groups. One group underwent upper extremity task training with symmetric abdominal muscle contraction (bracing) applied. The other group simply underwent upper extremity task training, without bracing. [Results] The experimental group’s Trunk Impairment Scale (TIS) significantly increased after the intervention, whereas the control group did not see any significant difference. There was significant improvement in balance after the intervention in both the experimental group and the control group. According to the between-group comparisons, the improvements in the experimental group were significantly greater in the control group, except in the Postural Assessment Scale (PASS). [Conclusion] Based on the results of this study, upper extremity task exercises with symmetric abdominal muscle contraction, conducted as part of adult hemiplegic patients’ trunk stabilization exercises, can be applied to a diverse range of hemiplegic patients and implemented as an exercise program after discharge from hospital. PMID:28356639

  4. The Efficacy of Functional Electrical Stimulation of the Abdominal Muscles in the Treatment of Chronic Constipation in Patients with Multiple Sclerosis: A Pilot Study

    PubMed Central

    Peace, Carla

    2016-01-01

    Chronic constipation in patients with multiple sclerosis (MS) is common and the current methods of treatment are ineffective in some patients. Anecdotal observations suggest that functional electrical stimulation (FES) of the abdominal muscles may be effective in the management of constipation in these patients. Patients and Methods. In this exploratory investigation we studied the effects of FES on the whole gut transit time (WGTT) and the colonic transit time (CTT). In addition, we evaluated the treatment effect on the patients' constipation-related quality of life and on the use of laxatives and the use of manual bowel evacuation. FES was given for 30 minutes twice a day for a period of six weeks. Four female patients were studied. Results. The WGTT and CTT and constipation-related quality of life improved in all patients. The patients' use of laxatives was reduced. No adverse effects of FES treatment were reported. Conclusion. The findings of this pilot study suggest that FES applied to the abdominal muscles may be an effective treatment modality for severe chronic constipation in patients with MS. PMID:27200190

  5. Inhibition of development of experimental abdominal aortic aneurysm by c-jun N-terminal protein kinase inhibitor combined with lysyl oxidase gene modified smooth muscle progenitor cells.

    PubMed

    Chen, Feng; Zhang, ZhenDong; Zhu, XianHua

    2015-11-05

    Chronic inflammation, imbalance between the extracellular matrix synthesis and degradation, and loss of vascular smooth muscle cells (SMCs) contribute to the development of abdominal aortic aneurysm (AAA). The purpose of this study was to investigate the effect of the therapy with periaortic incubation of c-Jun N-terminal protein kinase inhibitor SP600125 infused from an osmotic pump and subadventitial injection of lysyl oxidase (LOX) gene modified autologous smooth muscle progenitor cells (SPCs) on treatment of AAA in a rabbit model. Obvious dilation of the abdominal aorta in the control group was caused by periaortic incubation of calcium chloride and elastase. But the progression of aortic dilation was significantly decreased after the treatment with SP600125 and LOX gene modified SPCs compared to the treatment with phosphate-buffered saline. This therapy could inhibit matrix metalloproteinases expression, enhance elastin synthesis, improve preservation of elastic laminar integrity, benefit SPCs survival and restore SMCs population. It seemed that this method might provide a novel therapeutic strategy to treat AAA.

  6. Respiratory flow and vital signs associated with the intensity of functional electrical stimulation delivered to human abdominal muscles during quiet breathing

    PubMed Central

    Sewa, Yoko; Tomita, Kazuhide; Okuno, Yukako; Ose, Hirotaka; Imura, Shigeyuki

    2016-01-01

    [Purpose] The purpose of this study was to examine the effects of increasing the intensity of functional electrical stimulation delivered to abdominal muscles during quiet breathing on respiratory flow, vital signs and pain in healthy subjects. [Subjects and Methods] Electrical stimulation was delivered bilaterally using one pair of high-conductivity gel-skin plate electrodes, placed on both sides of the abdomen, to nine healthy males. Subjects were required to breathe normally through a face mask for 2 minutes while in a supine position. The stimulation intensity was incrementally increased by 10 mA until reaching 100 mA. Respiratory parameters, vital signs and pain based on the visual analog scale were measured for each intensity of electrical stimulation. [Results] Transcutaneous oxygen saturation showed a slight upward trend in association with increasing stimulation intensity, but there were no significant changes in pulse or blood pressure. Respiratory flow, tidal volume, and minute ventilation increased significantly as the stimulation intensity rose. [Conclusion] This study revealed that functional electrical stimulation can be safely delivered to human abdominal muscles without causing vital sign abnormalities. It was also found that the appropriate intensity level of electrical stimulation for achieving effects on respiratory flow while also minimizing pain is 60–80 mA. PMID:28174447

  7. Muscle contractile activity regulates Sirt3 protein expression in rat skeletal muscles.

    PubMed

    Hokari, Fumi; Kawasaki, Emi; Sakai, Atsushi; Koshinaka, Keiichi; Sakuma, Kunihiro; Kawanaka, Kentaro

    2010-08-01

    Sirt3, a member of the sirtuin family, is known to control cellular mitochondrial function. Furthermore, because sirtuins require NAD for their deacetylase activity, nicotinamide phosphoribosyltransferase (Nampt), which is a rate-limiting enzyme in the intracellular NAD biosynthetic pathway, influences their activity. We examined the effects of exercise training and normal postural contractile activity on Sirt3 and Nampt protein expression in rat skeletal muscles. Male rats were trained by treadmill running at 20 m/min, 60 min/day, 7 days/wk for 4 wk. This treadmill training program increased the Sirt3 protein expression in the soleus and plantaris muscles by 49% and 41%, respectively (P < 0.05). Moreover, a 4-wk voluntary wheel-running program also induced 66% and 95% increases in Sirt3 protein in the plantaris and triceps muscles of rats, respectively (P < 0.05). Treadmill-running and voluntary running training induced no significant changes in Nampt protein expression in skeletal muscles. In resting rats, the soleus muscle, which is recruited during normal postural activity, possessed the greatest expression levels of the Sirt3 and Nampt proteins, followed by the plantaris and triceps muscles. Furthermore, the Sirt3, but not Nampt, protein level was reduced in the soleus muscles from immobilized hindlimbs compared with that shown in the contralateral control muscle. These results demonstrated that 1) Sirt3 protein expression is upregulated by exercise training in skeletal muscles and 2) local postural contractile activity plays an important role in maintaining a high level of Sirt3 protein expression in postural muscle.

  8. Electrical activation of artificial muscles containing polyacrylonitrile gel fibers.

    PubMed

    Schreyer, H B; Gebhart, N; Kim, K J; Shahinpoor, M

    2000-01-01

    Gel fibers made from polyacrylonitrile (PAN) are known to elongate and contract when immersed in caustic and acidic solutions, respectively. The amount of contraction for these pH-activated fibers is 50% or greater, and the strength of these fibers is shown to be comparable to that of human muscle. Despite these attributes, the need of strong acids and bases for actuation has limited the use of PAN gel fibers as linear actuators or artificial muscles. Increasing the conductivity by depositing platinum on the fibers or combining the fibers with graphite fibers has allowed for electrical activation of artificial muscles containing gel fibers when placed in an electrochemical cell. The electrolysis of water in such a cell produces hydrogen ions at an artificial muscle anode, thus locally decreasing the pH and causing the muscle to contract. Reversing the electric field allows the PAN muscle to elongate. A greater than 40% contraction in artificial muscle length in less than 10 min is observed when it is placed as an electrode in a 10 mM NaCl electrolyte solution and connected to a 10 V power supply. These results indicate potential in developing electrically activated PAN muscles and linear actuators, which would be much more applicable than chemically activated muscles.

  9. Activation of upper airway muscles during breathing and swallowing

    PubMed Central

    Ludlow, Christy L.

    2013-01-01

    The upper airway is a complex muscular tube that is used by the respiratory and digestive systems. The upper airway is invested with several small and anatomically peculiar muscles. The muscle fiber orientations and their nervous innervation are both extremely complex, and how the activity of the muscles is initiated and adjusted during complex behaviors is poorly understood. The bulk of the evidence suggests that the entire assembly of tongue and laryngeal muscles operate together but differently during breathing and swallowing, like a ballet rather than a solo performance. Here we review the functional anatomy of the tongue and laryngeal muscles, and their neural innervation. We also consider how muscular activity is altered as respiratory drive changes, and briefly address upper airway muscle control during swallowing. PMID:24092695

  10. Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian Indians and recommendations for physical activity, medical and surgical management.

    PubMed

    Misra, A; Chowbey, P; Makkar, B M; Vikram, N K; Wasir, J S; Chadha, D; Joshi, Shashank R; Sadikot, S; Gupta, R; Gulati, Seema; Munjal, Y P

    2009-02-01

    Asian Indians exhibit unique features of obesity; excess body fat, abdominal adiposity, increased subcutaneous and intra-abdominal fat, and deposition of fat in ectopic sites (liver, muscle, etc.). Obesity is a major driver for the widely prevalent metabolic syndrome and type 2 diabetes mellitus (T2DM) in Asian Indians in India and those residing in other countries. Based on percentage body fat and morbidity data, limits of normal BMI are narrower and lower in Asian Indians than in white Caucasians. In this consensus statement, we present revised guidelines for diagnosis of obesity, abdominal obesity, the metabolic syndrome, physical activity, and drug therapy and bariatric surgery for obesity in Asian Indians after consultations with experts from various regions of India belonging to the following medical disciplines; internal medicine, metabolic diseases, endocrinology, nutrition, cardiology, exercise physiology, sports medicine and bariatric surgery, and representing reputed medical institutions, hospitals, government funded research institutions, and policy making bodies. It is estimated that by application of these guidelines, additional 10-15% of Indian population would be labeled as overweight/obese and would require appropriate management. Application of these guidelines on countrywide basis is also likely to have a deceleration effect on the escalating problem of T2DM and cardiovascular disease. These guidelines could be revised in future as appropriate, after another large and countrywide consensus process. Till that time, these should be used by clinicians, researchers and policymakers dealing with obesity and related diseases.

  11. Phasic-to-tonic shift in trunk muscle activity relative to walking during low-impact weight bearing exercise

    NASA Astrophysics Data System (ADS)

    Caplan, Nick; Gibbon, Karl; Hibbs, Angela; Evetts, Simon; Debuse, Dorothée

    2014-11-01

    The aim of this study was to investigate the influence of an exercise device, designed to improve the function of lumbopelvic muscles via low-impact weight-bearing exercise, on electromyographic (EMG) activity of lumbopelvic, including abdominal muscles. Surface EMG activity was collected from lumbar multifidus (LM), erector spinae (ES), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) during overground walking (OW) and exercise device (EX) conditions. During walking, most muscles showed peaks in activity which were not seen during EX. Spinal extensors (LM, ES) were more active in EX. Internal oblique and RA were less active in EX. In EX, LM and ES were active for longer than during OW. Conversely, EO and RA were active for a shorter duration in EX than OW. The exercise device showed a phasic-to-tonic shift in activation of both local and global lumbopelvic muscles and promoted increased activation of spinal extensors in relation to walking. These features could make the exercise device a useful rehabilitative tool for populations with lumbopelvic muscle atrophy and dysfunction, including those recovering from deconditioning due to long-term bed rest and microgravity in astronauts.

  12. Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology

    PubMed Central

    Rabey, Karyne N.; Green, David J.; Taylor, Andrea B.; Begun, David R.; Richmond, Brian G.; McFarlin, Shannon C.

    2014-01-01

    The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual’s past behaviour. PMID:25467113

  13. Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology.

    PubMed

    Rabey, Karyne N; Green, David J; Taylor, Andrea B; Begun, David R; Richmond, Brian G; McFarlin, Shannon C

    2015-01-01

    The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual's past behaviour.

  14. Physical activity in adolescence and abdominal obesity in adulthood: a case-control study among women shift workers.

    PubMed

    Garcez, Anderson da Silva; Olinto, Maria Teresa Anselmo; Canuto, Raquel; Olinto, Beatriz Anselmo; Pattussi, Marcos Pascoal; Paniz, Vera Maria Vieira

    2015-01-01

    Physical activity may have a protective effect against abdominal obesity, an important risk factor for cardiometabolic diseases. Thus, the aim of this study was to examine the association between the practice of physical activities in adolescence and abdominal obesity in adulthood among women shift workers in Southern Brazil in 2011. This case-control study included 215 cases (waist circumference greater than or equal to 88 cm) and 326 controls. For both the case and control groups, participation in leisure-time physical activities was most frequent in adolescence and was significantly less in adulthood. After adjusting for potential confounding factors, women who participated in five or more physical activities in adolescence were 50 percent less likely to have abdominal obesity than women who participated in one activity or no physical activities (Odds Ratio = 0.50; 95% confidential interval: 0.27-0.93, p value = .029). Participation in various types of leisure-time physical activities in adolescence may protect against abdominal obesity in adulthood, even if the number of physical activities decreases over time. This finding demonstrated the importance of physical activity as well as the period of life in which these should be encouraged for the prevention of health disorders, such as abdominal obesity.

  15. Repositioning forelimb superficialis muscles: tendon attachment and muscle activity enable active relocation of functional myofibers.

    PubMed

    Huang, Alice H; Riordan, Timothy J; Wang, Lingyan; Eyal, Shai; Zelzer, Elazar; Brigande, John V; Schweitzer, Ronen

    2013-09-16

    The muscles that govern hand motion are composed of extrinsic muscles that reside within the forearm and intrinsic muscles that reside within the hand. We find that the extrinsic muscles of the flexor digitorum superficialis (FDS) first differentiate as intrinsic muscles within the hand and then relocate as myofibers to their final position in the arm. This remarkable translocation of differentiated myofibers across a joint is dependent on muscle contraction and muscle-tendon attachment. Interestingly, the intrinsic flexor digitorum brevis (FDB) muscles of the foot are identical to the FDS in tendon pattern and delayed developmental timing but undergo limited muscle translocation, providing strong support for evolutionary homology between the FDS and FDB muscles. We propose that the intrinsic FDB pattern represents the original tetrapod limb and that translocation of the muscles to form the FDS is a mammalian evolutionary addition.

  16. Muscle Transcriptional Profile Based on Muscle Fiber, Mitochondrial Respiratory Activity, and Metabolic Enzymes

    PubMed Central

    Liu, Xuan; Du, Yang; Trakooljul, Nares; Brand, Bodo; Muráni, Eduard; Krischek, Carsten; Wicke, Michael; Schwerin, Manfred; Wimmers, Klaus; Ponsuksili, Siriluck

    2015-01-01

    Skeletal muscle is a highly metabolically active tissue that both stores and consumes energy. Important biological pathways that affect energy metabolism and metabolic fiber type in muscle cells may be identified through transcriptomic profiling of the muscle, especially ante mortem. Here, gene expression was investigated in malignant hyperthermia syndrome (MHS)-negative Duroc and Pietrian (PiNN) pigs significantly differing for the muscle fiber types slow-twitch-oxidative fiber (STO) and fast-twitch-oxidative fiber (FTO) as well as mitochondrial activity (succinate-dependent state 3 respiration rate). Longissimus muscle samples were obtained 24 h before slaughter and profiled using cDNA microarrays. Differential gene expression between Duroc and PiNN muscle samples were associated with protein ubiquitination, stem cell pluripotency, amyloid processing, and 3-phosphoinositide biosynthesis and degradation pathways. In addition, weighted gene co-expression network analysis within both breeds identified several co-expression modules that were associated with the proportion of different fiber types, mitochondrial respiratory activity, and ATP metabolism. In particular, Duroc results revealed strong correlations between mitochondrion-associated co-expression modules and STO (r = 0.78), fast-twitch glycolytic fiber (r = -0.98), complex I (r=0.72) and COX activity (r = 0.86). Other pathways in the protein-kinase-activity enriched module were positively correlated with STO (r=0.93), while negatively correlated with FTO (r = -0.72). In contrast to PiNN, co-expression modules enriched in macromolecule catabolic process, actin cytoskeleton, and transcription activator activity were associated with fiber types, mitochondrial respiratory activity, and metabolic enzyme activities. Our results highlight the importance of mitochondria for the oxidative capacity of porcine muscle and for breed-dependent molecular pathways in muscle cell fibers. PMID:26681915

  17. 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.

  18. ACTIVATION OF CASPASE-3 IN THE SKELETAL MUSCLE DURING HEMODIALYSIS

    PubMed Central

    Boivin, Michel A; Battah, Shadi I; Dominic, Elizabeth A; Kalantar-Zadeh, Kamyar; Ferrando, Arny; Tzamaloukas, Antonios H; Dwivedi, Rama; Ma, Thomas A; Moseley, Pope; Raj, Dominic SC

    2010-01-01

    Background Muscle atrophy in end-stage renal disease (ESRD) may be due to the activation of apoptotic and proteolytic pathways. Objective We hypothesized that activation of caspase-3 in the skeletal muscle mediates apoptosis and proteolysis during hemodialysis (HD). Materials and Methods Eight ESRD patients were studied before (pre-HD) and during HD and the finding were compared with those from six healthy volunteers. Protein kinetics was determined by primed constant infusion of L-(ring 13C6) Phenylalanine. Results Caspase-3 activity in the skeletal muscle was higher in ESRD patients pre-HD than in controls (24966.0±4023.9 vs. 15293.3±2120.0 units, p<0.01) and increased further during HD (end-HD) (37666.6±4208.3 units) (p<0.001). 14 kDa actin fragments generated by caspase-3 mediated cleavage of actinomyosin was higher in the skeletal muscle pre-HD (68%) and during HD (164%) compared to controls. The abundance of ubiquitinized carboxy-terminal actin fragment was also significantly increased during HD. Skeletal muscle biopsies obtained at the end of HD exhibited augmented apoptosis, which was higher than that observed in pre-HD and control samples (p<0.001). IL-6 content in the soluble fraction of the muscle skeletal muscle was increased significantly during HD. Protein kinetic studies showed that catabolism was higher in ESRD patients during HD compared to pre-HD and control subjects. Muscle protein catabolism was positively associated with caspase-3 activity and skeletal muscle IL-6 content. Conclusion Muscle atrophy in ESRD may be due to IL-6 induced activation of caspase-3 resulting in apoptosis as well as muscle proteolysis during HD. PMID:20636378

  19. Evidence of a central pattern generator regulating spermathecal muscle activity in Locusta migratoria and its coordination with oviposition.

    PubMed

    da Silva, Rosa; Lange, Angela B

    2011-03-01

    Electrophysiological recordings were conducted to determine the control of spermathecal contractions during oviposition of interrupted egg-laying locusts, Locusta migratoria. Following transection of the central nervous system below the metathoracic ganglion, rhythmic patterned bursting was detected by extracellular recordings of the nerve N2B2 that innervates the muscles of the spermatheca. Subsequent transections at more posterior regions of the ventral nerve cord revealed more robust rhythmic bursting in N2B2. This rhythmic bursting pattern was found to be coordinated with bursting in the ventral opener nerve (N2B1) that innervates the ventral opener muscle. This muscle controls the ventral ovipositor valves. Electromyographic recordings from the spermathecal muscle and ventral opener muscle confirmed a rhythmic bursting pattern resulting in an increase in muscle activity. Taken together, the results indicate that there is probably a central pattern generator (CPG), which is regulated by descending inhibition, that controls the spermathecal muscle activity. This CPG appears to be located within the VIIth and VIIIth abdominal ganglia, and was found to integrate with the CPG that regulates oviposition digging in locusts. These results provide further insight into the intricate coordination and control of reproductive tissues underlying reproductive behaviours in locusts.

  20. Muscle Activation during Gait in Children with Duchenne Muscular Dystrophy

    PubMed Central

    Vuillerot, Carole; Tiffreau, Vincent; Peudenier, Sylviane; Cuisset, Jean-Marie; Pereon, Yann; Leboeuf, Fabien; Delporte, Ludovic; Delpierre, Yannick; Gross, Raphaël

    2016-01-01

    The aim of this prospective study was to investigate changes in muscle activity during gait in children with Duchenne muscular Dystrophy (DMD). Dynamic surface electromyography recordings (EMGs) of 16 children with DMD and pathological gait were compared with those of 15 control children. The activity of the rectus femoris (RF), vastus lateralis (VL), medial hamstrings (HS), tibialis anterior (TA) and gastrocnemius soleus (GAS) muscles was recorded and analysed quantitatively and qualitatively. The overall muscle activity in the children with DMD was significantly different from that of the control group. Percentage activation amplitudes of RF, HS and TA were greater throughout the gait cycle in the children with DMD and the timing of GAS activity differed from the control children. Significantly greater muscle coactivation was found in the children with DMD. There were no significant differences between sides. Since the motor command is normal in DMD, the hyper-activity and co-contractions likely compensate for gait instability and muscle weakness, however may have negative consequences on the muscles and may increase the energy cost of gait. Simple rehabilitative strategies such as targeted physical therapies may improve stability and thus the pattern of muscle activity. PMID:27622734

  1. Effect of Expiratory Resistive Loading in Expiratory Muscle Strength Training on Orbicularis Oris Muscle Activity

    PubMed Central

    Yanagisawa, Yukio; Matsuo, Yoshimi; Shuntoh, Hisato; Horiuchi, Noriaki

    2014-01-01

    [Purpose] The purpose of this study was to elucidate the effect of expiratory resistive loading on orbicularis oris muscle activity. [Subjects] Subjects were 23 healthy individuals (11 males, mean age 25.5±4.3 years; 12 females, mean age 25.0±3.0 years). [Methods] Surface electromyography was performed to measure the activity of the orbicularis oris muscle during maximum lip closure and resistive loading at different expiratory pressures. Measurement was performed at 10%, 30%, 50%, and 100% of maximum expiratory pressure (MEP) for all subjects. The t-test was used to compare muscle activity between maximum lip closure and 100% MEP, and analysis of variance followed by multiple comparisons was used to compare the muscle activities observed at different expiratory pressures. [Results] No significant difference in muscle activity was observed between maximum lip closure and 100% MEP. Analysis of variance with multiple comparisons revealed significant differences among the different expiratory pressures. [Conclusion] Orbicularis oris muscle activity increased with increasing expiratory resistive loading. PMID:24648644

  2. Maximal force, voluntary activation and muscle soreness after eccentric damage to human elbow flexor muscles.

    PubMed

    Prasartwuth, O; Taylor, J L; Gandevia, S C

    2005-08-15

    Muscle damage reduces voluntary force after eccentric exercise but impaired neural drive to the muscle may also contribute. To determine whether the delayed-onset muscle soreness, which develops approximately 1 day after exercise, reduces voluntary activation and to identify the possible site for any reduction, voluntary activation of elbow flexor muscles was examined with both motor cortex and motor nerve stimulation. We measured maximal voluntary isometric torque (MVC), twitch torque, muscle soreness and voluntary activation in eight subjects before, immediately after, 2 h after, 1, 2, 4 and 8 days after eccentric exercise. Motor nerve stimulation and motor cortex stimulation were used to derive twitch torques and measures of voluntary activation. Eccentric exercise immediately reduced the MVC by 38 +/- 3% (mean +/- s.d., n = 8). The resting twitch produced by motor nerve stimulation fell by 82 +/- 6%, and the estimated resting twitch by cortical stimulation fell by 47 +/- 15%. While voluntary torque recovered after 8 days, both measures of the resting twitch remained depressed. Muscle tenderness occurred 1-2 days after exercise, and pain during contractions on days 1-4, but changes in voluntary activation did not follow this time course. Voluntary activation assessed with nerve stimulation fell 19 +/- 6% immediately after exercise but was not different from control values after 2 days. Voluntary activation assessed by motor cortex stimulation was unchanged by eccentric exercise. During MVCs, absolute increments in torque evoked by nerve and cortical stimulation behaved differently. Those to cortical stimulation decreased whereas those to nerve stimulation tended to increase. These findings suggest that reduced voluntary activation contributes to the early force loss after eccentric exercise, but that it is not due to muscle soreness. The impairment of voluntary activation to nerve stimulation but not motor cortical stimulation suggests that the activation

  3. Maximal force, voluntary activation and muscle soreness after eccentric damage to human elbow flexor muscles

    PubMed Central

    Prasartwuth, O; Taylor, JL; Gandevia, SC

    2005-01-01

    Muscle damage reduces voluntary force after eccentric exercise but impaired neural drive to the muscle may also contribute. To determine whether the delayed-onset muscle soreness, which develops ∼1 day after exercise, reduces voluntary activation and to identify the possible site for any reduction, voluntary activation of elbow flexor muscles was examined with both motor cortex and motor nerve stimulation. We measured maximal voluntary isometric torque (MVC), twitch torque, muscle soreness and voluntary activation in eight subjects before, immediately after, 2 h after, 1, 2, 4 and 8 days after eccentric exercise. Motor nerve stimulation and motor cortex stimulation were used to derive twitch torques and measures of voluntary activation. Eccentric exercise immediately reduced the MVC by 38 ± 3% (mean ±s.d., n = 8). The resting twitch produced by motor nerve stimulation fell by 82 ± 6%, and the estimated resting twitch by cortical stimulation fell by 47 ± 15%. While voluntary torque recovered after 8 days, both measures of the resting twitch remained depressed. Muscle tenderness occurred 1–2 days after exercise, and pain during contractions on days 1–4, but changes in voluntary activation did not follow this time course. Voluntary activation assessed with nerve stimulation fell 19 ± 6% immediately after exercise but was not different from control values after 2 days. Voluntary activation assessed by motor cortex stimulation was unchanged by eccentric exercise. During MVCs, absolute increments in torque evoked by nerve and cortical stimulation behaved differently. Those to cortical stimulation decreased whereas those to nerve stimulation tended to increase. These findings suggest that reduced voluntary activation contributes to the early force loss after eccentric exercise, but that it is not due to muscle soreness. The impairment of voluntary activation to nerve stimulation but not motor cortical stimulation suggests that the activation deficit lies in the

  4. Timing of Cortico-Muscle Transmission During Active Movement.

    PubMed

    Van Acker, Gustaf M; Luchies, Carl W; Cheney, Paul D

    2016-08-01

    Numerous studies have reported large disparities between short cortico-muscle conduction latencies and long recorded delays between cortical firing and evoked muscle activity. Using methods such as spike- and stimulus-triggered averaging of electromyographic (EMG) activity, previous studies have shown that the time delay between corticomotoneuronal (CM) cell firing and onset of facilitation of forelimb muscle activity ranges from 6.7 to 9.8 ms, depending on the muscle group tested. In contrast, numerous studies have reported delays of 60-122 ms between cortical cell firing onset and either EMG or movement onset during motor tasks. To further investigate this disparity, we simulated rapid active movement by applying frequency-modulated stimulus trains to M1 cortical sites in a rhesus macaque performing a movement task. This yielded corresponding EMG modulations, the latency of which could be measured relative to the stimulus modulations. The overall mean delay from stimulus frequency modulation to EMG modulation was 11.5 ± 5.6 ms, matching closely the conduction time through the cortico-muscle pathway (12.6 ± 2.0 ms) derived from poststimulus facilitation peaks computed at the same sites. We conclude that, during active movement, the delay between modulated M1 cortical output and its impact on muscle activity approaches the physical cortico-muscle conduction time.

  5. THE EFFECT OF DOUBLE VERSUS SINGLE OSCILLATING EXERCISE DEVICES ON TRUNK AND LIMB MUSCLE ACTIVATION

    PubMed Central

    Arora, Shruti; Button, Duane C.; Basset, Fabien A.

    2013-01-01

    Purpose/Background: Proper strengthening of the core and upper extremities is important for muscular health, performance, and rehabilitation. Exercise devices have been developed that attempt to disrupt the center of gravity in order to activate the trunk stabilizing muscles. The objective of this study was to analyze the trunk and shoulder girdle muscle activation with double and single oscillating exercise devices (DOD and SOD respectively) in various planes. Methods: Twelve male subjects performed three interventions using both devices under randomized conditions: single-handed vertical orientation of DOD and SOD to produce 1) medio-lateral oscillation in the frontal plane 2) dorso-ventral oscillation in the sagittal plane and 3) single-handed horizontal orientation for superior and inferior oscillation in the transverse plane. Electromyographic (EMG) activity during the interventions of the anterior deltoid, triceps brachii, biceps brachii, forearm flexors as well as lower abdominal and back stabilizer muscles was collected, and were normalized to maximal voluntary contractions. A two way repeated measures ANOVA (2x3) was conducted to assess the influence of the devices and movement planes on muscle activation. Results: The DOD provided 35.9%, 40.8%, and 52.3% greater anterior deltoid, transverse abdominus (TA)/internal oblique (IO) and lumbo-sacral erector spinae (LSES) activation than did the SOD respectively. Effect size calculations revealed that these differences were of moderate to large magnitude (0.86, 0.48, and 0.61 respectively). There were no significant differences in muscular activation achieved between devices for the triceps brachii, biceps brachii and forearm flexor muscles. Exercise in the transverse plane resulted in 30.5%, 29.5%, and 19.5% greater activation than the sagittal and 21.8%, 17.2%, and 26.3% greater activation than the frontal plane for the anterior deltoid, TA/IO and LSES respectively. Conclusions: A DOD demonstrated greater

  6. Acid phosphatase and protease activities in immobilized rat skeletal muscles

    NASA Technical Reports Server (NTRS)

    Witzmann, F. A.; Troup, J. P.; Fitts, R. H.

    1982-01-01

    The effect of hind-limb immobilization on selected Iysosomal enzyme activities was studied in rat hing-limb muscles composed primarily of type 1. 2A, or 2B fibers. Following immobilization, acid protease and acid phosphatase both exhibited signifcant increases in their activity per unit weight in all three fiber types. Acid phosphatase activity increased at day 14 of immobilization in the three muscles and returned to control levels by day 21. Acid protease activity also changed biphasically, displaying a higher and earlier rise than acid phosphatase. The pattern of change in acid protease, but not acid phosphatase, closely parallels observed muscle wasting. The present data therefore demonstrate enhanced proteolytic capacity of all three fiber types early during muscular atrophy. In addition, the data suggest a dependence of basal hydrolytic and proteolytic activities and their adaptive response to immobilization on muscle fiber composition.

  7. Regulation of myostatin activity and muscle growth.

    PubMed

    Lee, S J; McPherron, A C

    2001-07-31

    Myostatin is a transforming growth factor-beta family member that acts as a negative regulator of skeletal muscle mass. To identify possible myostatin inhibitors that may have applications for promoting muscle growth, we investigated the regulation of myostatin signaling. Myostatin protein purified from mammalian cells consisted of a noncovalently held complex of the N-terminal propeptide and a disulfide-linked dimer of C-terminal fragments. The purified C-terminal myostatin dimer was capable of binding the activin type II receptors, Act RIIB and, to a lesser extent, Act RIIA. Binding of myostatin to Act RIIB could be inhibited by the activin-binding protein follistatin and, at higher concentrations, by the myostatin propeptide. To determine the functional significance of these interactions in vivo, we generated transgenic mice expressing high levels of the propeptide, follistatin, or a dominant-negative form of Act RIIB by using a skeletal muscle-specific promoter. Independent transgenic mouse lines for each construct exhibited dramatic increases in muscle mass comparable to those seen in myostatin knockout mice. Our findings suggest that the propeptide, follistatin, or other molecules that block signaling through this pathway may be useful agents for enhancing muscle growth for both human therapeutic and agricultural applications.

  8. Saturated muscle activation contributes to compensatory reaching strategies following stroke

    PubMed Central

    McCrea, Patrick H; Eng, Janice J; Hodgson, Antony J

    2012-01-01

    The control and execution of movement could potentially be altered by the presence of stroke-induced weakness if muscles are incapable of generating sufficient power. The purpose of this study was to identify compensatory strategies during a forward (sagittal) reaching task for twenty persons with chronic stroke and ten healthy age-matched controls. We hypothesized that the paretic anterior deltoid would be maximally activated (i.e., saturated) during a reaching task and that task completion would require activation of additional muscles, resulting in compensatory movements out of the sagittal plane. For reaching movements by control subjects, joint motion remained largely in the sagittal plane and hand trajectories were smooth and direct. Movement characteristics of the non-paretic arm of stroke subjects were similar to control subjects except for small increases in the abduction angle and the percentage that anterior deltoid was activated. In contrast, reaching movements of the paretic arm of stroke subjects were characterized by increased activation of all muscles, especially the lateral deltoid, in addition to the anterior deltoid, with resulting shoulder abduction power and segmented and indirect hand motion. For the paretic arm of stroke subjects, muscle and kinetic compensations increased with impairment severity and weaker muscles were used at a higher percentage of their available muscle activity. These results suggest that the inability to generate sufficient force with the typical agonists involved during a forward reaching task may necessitate compensatory muscle recruitment strategies to complete the task. PMID:16014786

  9. Saturated muscle activation contributes to compensatory reaching strategies after stroke.

    PubMed

    McCrea, Patrick H; Eng, Janice J; Hodgson, Antony J

    2005-11-01

    The control and execution of movement could potentially be altered by the presence of stroke-induced weakness if muscles are incapable of generating sufficient power. The purpose of this study was to identify compensatory strategies during a forward (sagittal) reaching task for 20 persons with chronic stroke and 10 healthy age-matched controls. We hypothesized that the paretic anterior deltoid would be maximally activated (i.e., saturated) during a reaching task and that task completion would require activation of additional muscles, resulting in compensatory movements out of the sagittal plane. For reaching movements by control subjects, joint motion remained largely in the sagittal plane and hand trajectories were smooth and direct. Movement characteristics of the nonparetic arm of stroke subjects were similar to control subjects except for small increases in the abduction angle and the percentage that anterior deltoid was activated. In contrast, reaching movements of the paretic arm of stroke subjects were characterized by increased activation of all muscles, especially the lateral deltoid, in addition to the anterior deltoid, with resulting shoulder abduction power and segmented and indirect hand motion. For the paretic arm of stroke subjects, muscle and kinetic compensations increased with impairment severity and weaker muscles were used at a higher percentage of their available muscle activity. These results suggest that the inability to generate sufficient force with the typical agonists involved during a forward reaching task may necessitate compensatory muscle recruitment strategies to complete the task.

  10. Influence of playing wind instruments on activity of masticatory muscles.

    PubMed

    Gotouda, A; Yamaguchi, T; Okada, K; Matsuki, T; Gotouda, S; Inoue, N

    2007-09-01

    The aim of this study was to elucidate the influence of change in sound tone of playing wind instruments on activity of jaw-closing muscles and the effect of sustained playing for a long time on fatigue of jaw-closing muscles. Electromyograms (EMG) of 19 brass instrument players and 14 woodwind instrument players were measured while playing instruments in tuning tone and high tone and under other conditions. Nine brass instrument players and nine woodwind instrument players played instruments for 90 min. Before and after the exercise, power spectral analyses of EMG from masseter muscles at 50% of maximum voluntary clenching level were performed and mean power frequency (MPF) were calculated. Root mean square (RMS) of EMG in masseter and temporal muscles while playing were slightly larger than those at rest but extremely small in comparison with those during maximum clenching. Root mean square in orbicularis oris and digastric muscles were relatively large when playing instruments. In the brass instrument group, RMS in high tone was significantly higher than that in tuning tone in all muscles examined. In the woodwind instrument group, RMS in high tone was not significantly higher than that in tuning tone in those muscles. Mean power frequency was not decreased after sustained playing in both instrument groups. These findings indicate that contractive load to jaw-closing muscles when playing a wind instrument in both medium and high tone is very small and playing an instrument for a long time does not obviously induce fatigue of jaw-closing muscles.

  11. Respiratory Muscle Activity During Simultaneous Stationary Cycling and Inspiratory Muscle Training.

    PubMed

    Hellyer, Nathan J; Folsom, Ian A; Gaz, Dan V; Kakuk, Alynn C; Mack, Jessica L; Ver Mulm, Jacyln A

    2015-12-01

    Inspiratory muscle training (IMT) strengthens the muscles of respiration, improves breathing efficiency, and increases fitness. The IMT is generally performed independently of aerobic exercise; however, it is not clear whether there is added benefit of performing the IMT while simultaneously performing aerobic exercise in terms of activating and strengthening inspiratory muscles. The purpose of our study was to determine the effect of IMT on respiratory muscle electromyography (EMG) activity during stationary cycling in the upright and drops postures as compared with that when the IMT was performed alone. Diaphragm and sternocleidomastoid EMG activity was measured under different resting and cycling postures, with and without the use of the IMT at 40% maximal inspiratory pressure (n = 10; mean age 37). Cycling in an upright posture while simultaneously performing the IMT resulted in a significantly greater diaphragm EMG activity than while performing the IMT at rest in upright or drops postures (p ≤ 0.05). Cycling in drops postures while performing the IMT had a significantly greater diaphragm EMG activity than when performing the IMT at rest in either upright or drops postures (p ≤ 0.05). Sternocleidomastoid muscle activity increased with both cycling and IMT, although posture had little effect. These results support our hypothesis in that the IMT while cycling increases respiratory EMG activity to a significantly greater extent than when performing the IMT solely at rest, suggesting that the combination of IMT and cycling may provide an additive training effect.

  12. Demonstrating Electrical Activity in Nerve and Muscle. Part I

    ERIC Educational Resources Information Center

    Robinson, D. J.

    1975-01-01

    Describes a demonstration for showing the electrical activity in nerve and muscle including action potentials, refractory period of a nerve, and fatigue. Presents instructions for constructing an amplifier, electronic stimulator, and force transducer. (GS)

  13. Breakpoints in ventilation, cerebral and muscle oxygenation, and muscle activity during an incremental cycling exercise

    PubMed Central

    Racinais, Sebastien; Buchheit, Martin; Girard, Olivier

    2014-01-01

    The aim of this study was to locate the breakpoints of cerebral and muscle oxygenation and muscle electrical activity during a ramp exercise in reference to the first and second ventilatory thresholds. Twenty-five cyclists completed a maximal ramp test on an electromagnetically braked cycle-ergometer with a rate of increment of 25 W/min. Expired gazes (breath-by-breath), prefrontal cortex and vastus lateralis (VL) oxygenation [Near-infrared spectroscopy (NIRS)] together with electromyographic (EMG) Root Mean Square (RMS) activity for the VL, rectus femoris (RF), and biceps femoris (BF) muscles were continuously assessed. There was a non-linear increase in both cerebral deoxyhemoglobin (at 56 ± 13% of the exercise) and oxyhemoglobin (56 ± 8% of exercise) concomitantly to the first ventilatory threshold (57 ± 6% of exercise, p > 0.86, Cohen's d < 0.1). Cerebral deoxyhemoglobin further increased (87 ± 10% of exercise) while oxyhemoglobin reached a plateau/decreased (86 ± 8% of exercise) after the second ventilatory threshold (81 ± 6% of exercise, p < 0.05, d > 0.8). We identified one threshold only for muscle parameters with a non-linear decrease in muscle oxyhemoglobin (78 ± 9% of exercise), attenuation in muscle deoxyhemoglobin (80 ± 8% of exercise), and increase in EMG activity of VL (89 ± 5% of exercise), RF (82 ± 14% of exercise), and BF (85 ± 9% of exercise). The thresholds in BF and VL EMG activity occurred after the second ventilatory threshold (p < 0.05, d > 0.6). Our results suggest that the metabolic and ventilatory events characterizing this latter cardiopulmonary threshold may affect both cerebral and muscle oxygenation levels, and in turn, muscle recruitment responses. PMID:24782786

  14. Effects of muscle activation on shear between human soleus and gastrocnemius muscles.

    PubMed

    Finni, T; Cronin, N J; Mayfield, D; Lichtwark, G A; Cresswell, A G

    2017-01-01

    Lateral connections between muscles provide pathways for myofascial force transmission. To elucidate whether these pathways have functional roles in vivo, we examined whether activation could alter the shear between the soleus (SOL) and lateral gastrocnemius (LG) muscles. We hypothesized that selective activation of LG would decrease the stretch-induced shear between LG and SOL. Eleven volunteers underwent a series of knee joint manipulations where plantar flexion force, LG, and SOL muscle fascicle lengths and relative displacement of aponeuroses between the muscles were obtained. Data during a passive full range of motion were recorded, followed by 20° knee extension stretches in both passive conditions and with selective electrical stimulation of LG. During active stretch, plantar flexion force was 22% greater (P < 0.05) and relative displacement of aponeuroses was smaller than during passive stretch (P < 0.05). Soleus fascicle length changes did not differ between passive and active stretches but LG fascicles stretched less in the active than passive condition when the stretch began at angles of 70° and 90° of knee flexion (P < 0.05). The activity-induced decrease in the relative displacement of SOL and LG suggests stronger (stiffer) connectivity between the two muscles, at least at flexed knee joint angles, which may serve to facilitate myofascial force transmission.

  15. Muscle Atrophy Reversed by Growth Factor Activation of Satellite Cells in a Mouse Muscle Atrophy Model

    PubMed Central

    Hauerslev, Simon; Vissing, John; Krag, Thomas O.

    2014-01-01

    Muscular dystrophies comprise a large group of inherited disorders that lead to progressive muscle wasting. We wanted to investigate if targeting satellite cells can enhance muscle regeneration and thus increase muscle mass. We treated mice with hepatocyte growth factor and leukemia inhibitory factor under three conditions: normoxia, hypoxia and during myostatin deficiency. We found that hepatocyte growth factor treatment led to activation of the Akt/mTOR/p70S6K protein synthesis pathway, up-regulation of the myognic transcription factors MyoD and myogenin, and subsequently the negative growth control factor, myostatin and atrophy markers MAFbx and MuRF1. Hypoxia-induced atrophy was partially restored by hepatocyte growth factor combined with leukemia inhibitory factor treatment. Dividing satellite cells were three-fold increased in the treatment group compared to control. Finally, we demonstrated that myostatin regulates satellite cell activation and myogenesis in vivo following treatment, consistent with previous findings in vitro. Our results suggest, not only a novel in vivo pharmacological treatment directed specifically at activating the satellite cells, but also a myostatin dependent mechanism that may contribute to the progressive muscle wasting seen in severely affected patients with muscular dystrophy and significant on-going regeneration. This treatment could potentially be applied to many conditions that feature muscle wasting to increase muscle bulk and strength. PMID:24963862

  16. Muscle atrophy reversed by growth factor activation of satellite cells in a mouse muscle atrophy model.

    PubMed

    Hauerslev, Simon; Vissing, John; Krag, Thomas O

    2014-01-01

    Muscular dystrophies comprise a large group of inherited disorders that lead to progressive muscle wasting. We wanted to investigate if targeting satellite cells can enhance muscle regeneration and thus increase muscle mass. We treated mice with hepatocyte growth factor and leukemia inhibitory factor under three conditions: normoxia, hypoxia and during myostatin deficiency. We found that hepatocyte growth factor treatment led to activation of the Akt/mTOR/p70S6K protein synthesis pathway, up-regulation of the myognic transcription factors MyoD and myogenin, and subsequently the negative growth control factor, myostatin and atrophy markers MAFbx and MuRF1. Hypoxia-induced atrophy was partially restored by hepatocyte growth factor combined with leukemia inhibitory factor treatment. Dividing satellite cells were three-fold increased in the treatment group compared to control. Finally, we demonstrated that myostatin regulates satellite cell activation and myogenesis in vivo following treatment, consistent with previous findings in vitro. Our results suggest, not only a novel in vivo pharmacological treatment directed specifically at activating the satellite cells, but also a myostatin dependent mechanism that may contribute to the progressive muscle wasting seen in severely affected patients with muscular dystrophy and significant on-going regeneration. This treatment could potentially be applied to many conditions that feature muscle wasting to increase muscle bulk and strength.

  17. Hypothermia Increases Tissue Plasminogen Activator Expression and Decreases Post-Operative Intra-Abdominal Adhesion

    PubMed Central

    Lee, Chien-Chang; Wang, Hsuan-Mao; Chou, Tzung-Hsin; Wu, Meng-Che; Hsueh, Kuang-Lung; Chen, Shyr-Chyr

    2016-01-01

    Background Therapeutic hypothermia during operation decreases postoperative intra-abdominal adhesion formation. We sought to determine the most appropriate duration of hypothermia, and whether hypothermia affects the expression of tissue plasminogen activator (tPA). Methods 80 male BALB/c mice weighing 25–30 g are randomized into one of five groups: adhesion model with infusion of 15°C saline for 15 minutes (A); 30 minutes (B); 45 minute (C); adhesion model without infusion of cold saline (D); and sham operation without infusion of cold saline (E). Adhesion scores and tPA levels in the peritoneum fluid levels were analyzed on postoperative days 1, 7, and 14. Results On day 14, the cold saline infusion groups (A, B, and C) had lower adhesion scores than the without infusion of cold saline group (D). However, only group B (cold saline infusion for 30 minutes) had a significantly lower adhesion scores than group D. Also, group B was found to have 3.4 fold, 2.3 fold, and 2.2 fold higher levels of tPA than group D on days 1, 7, and 14 respectively. Conclusions Our results suggest that cold saline infusion for 30 minutes was the optimum duration to decrease postoperative intra-abdominal adhesion formation. The decrease in the adhesion formations could be partly due to an increase in the level of tPA. PMID:27583464

  18. Activity Dependent Signal Transduction in Skeletal Muscle

    NASA Technical Reports Server (NTRS)

    Hamilton, Susan L.

    1999-01-01

    The overall goals of this project are: 1) to define the initial signal transduction events whereby the removal of gravitational load from antigravity muscles, such as the soleus, triggers muscle atrophy, and 2) to develop countermeasures to prevent this from happening. Our rationale for this approach is that, if countermeasures can be developed to regulate these early events, we could avoid having to deal with the multiple cascades of events that occur downstream from the initial event. One of our major findings is that hind limb suspension causes an early and sustained increase in intracellular Ca(2+) concentration ([Ca (2+)](sub i)). In most cells the consequences of changes in ([Ca (2+)](sub i))depend on the amplitude, frequency and duration of the Ca(2+) signal and on other factors in the intracellular environment. We propose that muscle remodeling in microgravity represents a change in the balance among several CA(2+) regulated signal transduction pathways, in particular those involving the transcription factors NFAT and NFkB and the pro-apoptotic protein BAD. Other Ca(2+) sensitive pathways involving PKC, ras, rac, and CaM kinase II may also contribute to muscle remodeling.

  19. Comparison of total lipids and fatty acids from liver, heart and abdominal muscle of scalloped (Sphyrna lewini) and smooth (Sphyrna zygaena) hammerhead sharks.

    PubMed

    Davidson, Bruce Clement; Nel, Wynand; Rais, Afsha; Namdarizandi, Vahid; Vizarra, Scott; Cliff, Geremy

    2014-01-01

    Liver, heart and abdominal muscle samples from scalloped (Sphyrna lewini) and smooth (Sphyrna zygaena) hammerhead sharks were analysed to characterise their lipid and fatty acid profiles. Samples were compared both between and within species, but there were no significant differences in total lipids for either comparison, although much greater total amounts were found in the liver samples. Within the individual fatty acids, the only significant differences were greater amounts of 22:6n-3, total n-3 polyunsaturates and total polyunsaturates in smooth, when compared to scalloped, hammerhead liver. This may reflect the more wide spread distribution of this species into cooler waters. Within both species the liver levels of the same fatty acid fractions decreased from spring to summer, which may correlate with changes in fatty acid profile to adapt to any differences in amount or species of prey consumed, or other considerations, eg. buoyancy, however there was no data to clarify this.

  20. Acute Effects of Whole-Body Vibration on Trunk and Neck Muscle Activity in Consideration of Different Vibration Loads

    PubMed Central

    Perchthaler, Dennis; Hauser, Simon; Heitkamp, Hans-Christian; Hein, Tobias; Grau, Stefan

    2015-01-01

    The intention of this study was to systematically analyze the impact of biomechanical parameters in terms of different peak-to-peak displacements and knee angles on trunk and neck muscle activity during whole-body vibration (WBV). 28 healthy men and women (age 23 ± 3 years) performed four static squat positions (2 peak-to-peak displacements x 2 knee angles) on a side alternating vibration platform with and without vibration stimulus. Surface electromyography (EMG) was used to record the neuromuscular activity of the erector spinae muscle, the rectus abdominis muscle, and of the splenius muscle. EMG levels normalized to maximal voluntary contractions ranged between 3.2 – 27.2 % MVC during WBV. The increase in muscle activity caused by WBV was significant, particularly for the back muscles, which was up to 19.0 % MVC. The impact of the factor ‘condition’ (F-values ranged from 13.4 to 132.0, p ≤ 0.001) and of the factor ‘peak-to-peak displacement’ (F-values ranged from 6.4 to 69.0 and p-values from < 0.001 to 0.01) were statistically significant for each muscle tested. However, the factor ‘knee angle’ only affected the back muscles (F-value 10.3 and 7.3, p ≤ 0.01). The results of this study should give more information for developing effective and safe training protocols for WBV treatment of the upper body. Key points The maximum levels of muscle activity were significantly reached at high amplitudes at a vibration frequency of 30 Hz. WBV leads to a higher muscle activation of the lower back muscles than of the abdominal muscles. Both knee angles of 30° and 45° have similar effects on the vibration load and represent safe positions to prevent any actual harm. Certain combinations of the biomechanical variables have similar effects on the level of muscle activity. PMID:25729303

  1. Baroreflex modulation of muscle sympathetic nerve activity during posthandgrip muscle ischemia in humans

    NASA Technical Reports Server (NTRS)

    Cui, J.; Wilson, T. E.; Shibasaki, M.; Hodges, N. A.; Crandall, C. G.

    2001-01-01

    To identify whether muscle metaboreceptor stimulation alters baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA, beat-by-beat arterial blood pressure (Finapres), and electrocardiogram were recorded in 11 healthy subjects in the supine position. Subjects performed 2 min of isometric handgrip exercise at 40% of maximal voluntary contraction followed by 2.5 min of posthandgrip muscle ischemia. During muscle ischemia, blood pressure was lowered and then raised by intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure was more negative (P < 0.001) during posthandgrip muscle ischemia (-201.9 +/- 20.4 units. beat(-1). mmHg(-1)) when compared with control conditions (-142.7 +/- 17.3 units. beat(-1). mmHg(-1)). No significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. However, both curves shifted during postexercise ischemia to accommodate the elevation in blood pressure and MSNA that occurs with this condition. These data suggest that the sensitivity of baroreflex modulation of MSNA is elevated by muscle metaboreceptor stimulation, whereas the sensitivity of baroreflex of modulate heart rate is unchanged during posthandgrip muscle ischemia.

  2. Force steadiness, muscle activity, and maximal muscle strength in subjects with subacromial impingement syndrome.

    PubMed

    Bandholm, Thomas; Rasmussen, Lars; Aagaard, Per; Jensen, Bente Rona; Diederichsen, Louise

    2006-11-01

    We investigated the effects of the subacromial impingement syndrome (SIS) on shoulder sensory-motor control and maximal shoulder muscle strength. It was hypothesized that both would be impaired due to chronic shoulder pain associated with the syndrome. Nine subjects with unilateral SIS who remained physically active in spite of shoulder pain and nine healthy matched controls were examined to determine isometric and isokinetic submaximal shoulder-abduction force steadiness at target forces corresponding to 20%, 27.5%, and 35% of the maximal shoulder abductor torque, and maximal shoulder muscle strength (MVC). Electromyographic (EMG) activity was assessed using surface and intramuscular recordings from eight shoulder muscles. Force steadiness was impaired in SIS subjects during concentric contractions at the highest target force level only, with muscle activity largely unaffected. No between-group differences in shoulder MVC were observed. The present data suggest that shoulder sensory-motor control is only mildly impaired in subjects with SIS who are able to continue with upper body physical activity in spite of shoulder pain. Thus, physical activity should be continued by patients with SIS, if possible, to avoid the loss in neural and muscle functions associated with inactivity.

  3. Muscle torque preservation and physical activity in individuals with stroke

    PubMed Central

    Eng, Janice J.; Lomaglio, Melanie J.; MacIntyre, Donna L.

    2011-01-01

    Background A greater percent loss of concentric versus eccentric muscle torque (i.e., relative eccentric muscle torque preservation) has been reported in the paretic limb of individuals with stroke and has been attributed to hypertonia and/or co-contractions. Stroke provides a unique condition for examining mechanisms underlying eccentric muscle preservation because both limbs experience similar amounts of general physical activity, but the paretic side is impaired directly by the brain lesion. Purpose The purpose of this study was to determine 1) whether eccentric preservation also exists in the nonparetic limb and 2) the relationship of eccentric or concentric torque preservation with physical activity in stroke. We hypothesized that the nonparetic muscles would demonstrate eccentric muscle preservation, which would suggest that non-neural mechanisms may also contribute to its relative preservation. Methods Eighteen stroke and 18 healthy control subjects (age and sex matched) completed a physical activity questionnaire. Maximum voluntary concentric and eccentric joint torques of the ankle, knee and hip flexors and extensors were measured using an isokinetic dynamometer at 30°/s for the paretic and nonparetic muscles. Relative concentric and eccentric peak torque preservation were expressed as a percentage of control subject torque. Results Relative eccentric torque was higher (more preserved) than relative concentric torque for paretic, as well as nonparetic muscles. Physical activity correlated with paretic (r=0.640, p=0.001) and nonparetic concentric torque preservation (r=0.508, p=0.009), but not with eccentric torque preservation for either leg. Conclusions The relative preservation of eccentric torque in the nonparetic muscles suggest a role of non-neural mechanisms and could also explain the preservation observed in other chronic health conditions. Loss of concentric, but not eccentric muscle torque was related to physical inactivity in stroke. PMID

  4. The relationship between human skeletal muscle pyruvate dehydrogenase phosphatase activity and muscle aerobic capacity.

    PubMed

    Love, Lorenzo K; LeBlanc, Paul J; Inglis, J Greig; Bradley, Nicolette S; Choptiany, Jon; Heigenhauser, George J F; Peters, Sandra J

    2011-08-01

    Pyruvate dehydrogenase (PDH) is a mitochondrial enzyme responsible for regulating the conversion of pyruvate to acetyl-CoA for use in the tricarboxylic acid cycle. PDH is regulated through phosphorylation and inactivation by PDH kinase (PDK) and dephosphorylation and activation by PDH phosphatase (PDP). The effect of endurance training on PDK in humans has been investigated; however, to date no study has examined the effect of endurance training on PDP in humans. Therefore, the purpose of this study was to examine differences in PDP activity and PDP1 protein content in human skeletal muscle across a range of muscle aerobic capacities. This association is important as higher PDP activity and protein content will allow for increased activation of PDH, and carbohydrate oxidation. The main findings of this study were that 1) PDP activity (r(2) = 0.399, P = 0.001) and PDP1 protein expression (r(2) = 0.153, P = 0.039) were positively correlated with citrate synthase (CS) activity as a marker for muscle aerobic capacity; 2) E1α (r(2) = 0.310, P = 0.002) and PDK2 protein (r(2) = 0.229, P =0.012) are positively correlated with muscle CS activity; and 3) although it is the most abundant isoform, PDP1 protein content only explained ∼ 18% of the variance in PDP activity (r(2) = 0.184, P = 0.033). In addition, PDP1 in combination with E1α explained ∼ 38% of the variance in PDP activity (r(2) = 0.383, P = 0.005), suggesting that there may be alternative regulatory mechanisms of this enzyme other than protein content. These data suggest that with higher muscle aerobic capacity (CS activity) there is a greater capacity for carbohydrate oxidation (E1α), in concert with higher potential for PDH activation (PDP activity).

  5. Investigation of trunk muscle activities during lifting using a multi-objective optimization-based model and intelligent optimization algorithms.

    PubMed

    Ghiasi, Mohammad Sadegh; Arjmand, Navid; Boroushaki, Mehrdad; Farahmand, Farzam

    2016-03-01

    A six-degree-of-freedom musculoskeletal model of the lumbar spine was developed to predict the activity of trunk muscles during light, moderate and heavy lifting tasks in standing posture. The model was formulated into a multi-objective optimization problem, minimizing the sum of the cubed muscle stresses and maximizing the spinal stability index. Two intelligent optimization algorithms, i.e., the vector evaluated particle swarm optimization (VEPSO) and nondominated sorting genetic algorithm (NSGA), were employed to solve the optimization problem. The optimal solution for each task was then found in the way that the corresponding in vivo intradiscal pressure could be reproduced. Results indicated that both algorithms predicted co-activity in the antagonistic abdominal muscles, as well as an increase in the stability index when going from the light to the heavy task. For all of the light, moderate and heavy tasks, the muscles' activities predictions of the VEPSO and the NSGA were generally consistent and in the same order of the in vivo electromyography data. The proposed methodology is thought to provide improved estimations for muscle activities by considering the spinal stability and incorporating the in vivo intradiscal pressure data.

  6. Torsion of an intra-abdominal testis.

    PubMed

    Lewis; Roller; Parra; Cotlar

    2000-09-01

    To present a case of torsion of a nonneoplastic intra-abdominal testis with an unusual clinical presentation.A 26-year-old active duty Navy Petty Officer presented to the emergency department on 3 occasions over a 5-day period with lower abdominal pain. Physical examination demonstrated acute tenderness in the left lower quadrant with sugestion of a normal spermatic cord and atrophic testis in the left scrotum. Computed tomography scan demonstrated an intra-abdominal lesion near the internal inguinal ring. The patient underwent surgical exploration through an inguinal incision. Torsion of a nonviable intra-abdominal testis was present. The scrotum contained only the vas deferens and cremasteric muscle. An orchiectomy was performed with removal of the vas deferens and other cord structures.The unusual clinical finding of acute torsion of an intra-abdominal testis, associated with an apparent atrophic scrotal testis, presented a confusing clinical picture. Computed tomography scan did not clarify the issue sufficiently to establish a definite preoperative diagnosis. Clinical suspicion prompted early surgical intervention. Review of the current literature produced 60 reported cases of torsion of an intra-abdominal testis. Two thirds of these involved testicular neoplasm, usually seminoma. Although the clinical presentation varied, most patients had recent onset of lower abdominal pain associated with tenderness and, in half the cases, a mass. Patients almost always presented with an absent scrotal testis on the involved side, and not infrequently reported previous surgery thought to be an orchiectomy.Diagnosis of an intra-abdominal testicular torsion is rare, particularly when no neoplasm is present. A high index of suspicion must be maintained whenever there is abdominal pain and undescended testis. The surgical history and imaging studies may not clarify a confusing clinical picture.

  7. Muscle Activity During Unilateral vs. Bilateral Battle Rope Exercises.

    PubMed

    Calatayud, Joaquin; Martin, Fernando; Colado, Juan C; Benítez, Josep C; Jakobsen, Markus D; Andersen, Lars L

    2015-10-01

    High training intensity is important for efficient strength gains. Although battle rope training is metabolically demanding, no studies have quantified intensity of muscle activity during this type of training. This study analyzes muscle activity during unilateral alternating waves vs. bilateral waves of battle rope training. Twenty-one volunteers participated in a repeated-measures study on 2 different occasions. Surface electromyographic signals were recorded from the anterior deltoid (AD), external oblique (OBLIQ), lumbar erector spinae (LUMB), and gluteus medius (GM) during bilateral waves and unilateral waves and were normalized to the maximum voluntary isometric contraction (MVIC). Results showed that muscle activity ranged from 51%MVIC to 73%MVIC for AD, OBLIQ, and LUMB, whereas GM muscle activity was only 14-18%MVIC. OBLIQ activation was significantly greater (20%MVIC; p = 0.02) with the unilateral waves compared with the bilateral waves, whereas LUMB signal was significantly higher (16%MVIC; p = 0.001) with the bilateral waves compared with the unilateral waves. In conclusion, both wave movements can be used to provide moderate to high levels of muscle activity in the AD, OBLIQ, and LUMB. Fitness practitioners aiming for higher OBLIQ activity should perform unilateral waves, whereas the bilateral variation of the movement can be used for higher LUMB activity.

  8. Muscle activity and inactivity periods during normal daily life.

    PubMed

    Tikkanen, Olli; Haakana, Piia; Pesola, Arto J; Häkkinen, Keijo; Rantalainen, Timo; Havu, Marko; Pullinen, Teemu; Finni, Taija

    2013-01-01

    Recent findings suggest that not only the lack of physical activity, but also prolonged times of sedentary behaviour where major locomotor muscles are inactive, significantly increase the risk of chronic diseases. The purpose of this study was to provide details of quadriceps and hamstring muscle inactivity and activity during normal daily life of ordinary people. Eighty-four volunteers (44 females, 40 males, 44.1±17.3 years, 172.3±6.1 cm, 70.1±10.2 kg) were measured during normal daily life using shorts measuring muscle electromyographic (EMG) activity (recording time 11.3±2.0 hours). EMG was normalized to isometric MVC (EMG(MVC)) during knee flexion and extension, and inactivity threshold of each muscle group was defined as 90% of EMG activity during standing (2.5±1.7% of EMG(MVC)). During normal daily life the average EMG amplitude was 4.0±2.6% and average activity burst amplitude was 5.8±3.4% of EMG(MVC) (mean duration of 1.4±1.4 s) which is below the EMG level required for walking (5 km/h corresponding to EMG level of about 10% of EMG(MVC)). Using the proposed individual inactivity threshold, thigh muscles were inactive 67.5±11.9% of the total recording time and the longest inactivity periods lasted for 13.9±7.3 min (2.5-38.3 min). Women had more activity bursts and spent more time at intensities above 40% EMG(MVC) than men (p<0.05). In conclusion, during normal daily life the locomotor muscles are inactive about 7.5 hours, and only a small fraction of muscle's maximal voluntary activation capacity is used averaging only 4% of the maximal recruitment of the thigh muscles. Some daily non-exercise activities such as stair climbing produce much higher muscle activity levels than brisk walking, and replacing sitting by standing can considerably increase cumulative daily muscle activity.

  9. Fractionation of muscle activity in rapid responses to startling cues

    PubMed Central

    Dean, Lauren R.

    2017-01-01

    Movements in response to acoustically startling cues have shorter reaction times than those following less intense sounds; this is known as the StartReact effect. The neural underpinnings for StartReact are unclear. One possibility is that startling cues preferentially invoke the reticulospinal tract to convey motor commands to spinal motoneurons. Reticulospinal outputs are highly divergent, controlling large groups of muscles in synergistic patterns. By contrast the dominant pathway in primate voluntary movement is the corticospinal tract, which can access small groups of muscles selectively. We therefore hypothesized that StartReact responses would be less fractionated than standard voluntary reactions. Electromyogram recordings were made from 15 muscles in 10 healthy human subjects as they carried out 32 varied movements with the right forelimb in response to startling and nonstartling auditory cues. Movements were chosen to elicit a wide range of muscle activations. Multidimensional muscle activity patterns were calculated at delays from 0 to 100 ms after the onset of muscle activity and subjected to principal component analysis to assess fractionation. In all cases, a similar proportion of the total variance could be explained by a reduced number of principal components for the startling and the nonstartling cue. Muscle activity patterns for a given task were very similar in response to startling and nonstartling cues. This suggests that movements produced in the StartReact paradigm rely on similar contributions from different descending pathways as those following voluntary responses to nonstartling cues. NEW & NOTEWORTHY We demonstrate that the ability to activate muscles selectively is preserved during the very rapid reactions produced following a startling cue. This suggests that the contributions from different descending pathways are comparable between these rapid reactions and more typical voluntary movements. PMID:28003416

  10. Effects of Physical Activity and Inactivity on Muscle Fatigue

    PubMed Central

    Bogdanis, Gregory C.

    2012-01-01

    The aim of this review was to examine the mechanisms by which physical activity and inactivity modify muscle fatigue. It is well known that acute or chronic increases in physical activity result in structural, metabolic, hormonal, neural, and molecular adaptations that increase the level of force or power that can be sustained by a muscle. These adaptations depend on the type, intensity, and volume of the exercise stimulus, but recent studies have highlighted the role of high intensity, short-duration exercise as a time-efficient method to achieve both anaerobic and aerobic/endurance type adaptations. The factors that determine the fatigue profile of a muscle during intense exercise include muscle fiber composition, neuromuscular characteristics, high energy metabolite stores, buffering capacity, ionic regulation, capillarization, and mitochondrial density. Muscle fiber-type transformation during exercise training is usually toward the intermediate type IIA at the expense of both type I and IIx myosin heavy-chain isoforms. High-intensity training results in increases of both glycolytic and oxidative enzymes, muscle capillarization, improved phosphocreatine resynthesis and regulation of K+, H+, and lactate ions. Decreases of the habitual activity level due to injury or sedentary lifestyle result in partial or even compete reversal of the adaptations due to previous training, manifested by reductions in fiber cross-sectional area, decreased oxidative capacity, and capillarization. Complete immobilization due to injury results in markedly decreased force output and fatigue resistance. Muscle unloading reduces electromyographic activity and causes muscle atrophy and significant decreases in capillarization and oxidative enzymes activity. The last part of the review discusses the beneficial effects of intermittent high-intensity exercise training in patients with different health conditions to demonstrate the powerful effect of exercise on health and well being. PMID

  11. Interrelationships between changes in anthropometric variables and computed tomography indices of abdominal fat distribution in response to a 1-year physical activity-healthy eating lifestyle modification program in abdominally obese men.

    PubMed

    Villeneuve, Nicole; Pelletier-Beaumont, Emilie; Nazare, Julie-Anne; Lemieux, Isabelle; Alméras, Natalie; Bergeron, Jean; Tremblay, Angelo; Poirier, Paul; Després, Jean-Pierre

    2014-04-01

    The objectives were to (i) measure the effects of a 1-year lifestyle modification program on body fat distribution/anthropometric variables; (ii) determine the interrelationships between changes in all these variables; and (iii) investigate whether there is a selective reduction in deep (DSAT) vs. superficial subcutaneous adipose tissue (SSAT) at the abdominal level following a 1-year lifestyle modification program. Anthropometric variables, body composition and abdominal and midthigh fat distribution were assessed at baseline and after 1 year in 109 sedentary, dyslipidemic and abdominally obese men. Reductions in anthropometric variables, skinfold thicknesses (except the trunk/extremity ratio) and fat mass as well as an increase in fat-free mass were observed after 1 year (p < 0.0001). Decreases in abdominal adipose tissue volumes were also noted (-23%, -26%, -18%, -19%, -17%, p < 0.0001 for total adipose tissue, visceral adipose tissue, subcutaneous adipose tissue, DSAT and SSAT, respectively). Adipose tissue areas at midthigh also decreased (-18%, -18%, -17%, p < 0.0001 for total, deep, and subcutaneous adipose tissue, respectively). A reduction (-9%, p < 0.0001) in low-attenuation muscle area and an increase (+1%, p < 0.05) in normal-attenuation muscle area were also observed. There was a positive relationship between changes in visceral adipose tissue and changes in DSAT (r = 0.65, p < 0.0001) or SSAT (r = 0.63, p < 0.0001). Although absolute changes in DSAT were greater than changes in SSAT, relative changes in both depots were similar, independent of changes in visceral adipose tissue. The 1-year lifestyle modification program therefore improved the body fat distribution pattern and midthigh muscle quality in abdominally obese men.

  12. Impact of different body positions on bioelectrical activity of the pelvic floor muscles in nulliparous continent women.

    PubMed

    Chmielewska, Daria; Stania, Magdalena; Sobota, Grzegorz; Kwaśna, Krystyna; Błaszczak, Edward; Taradaj, Jakub; Juras, Grzegorz

    2015-01-01

    We examined pelvic floor muscles (PFM) activity (%MVC) in twenty nulliparous women by body position during exercise as well as the activation of abdominal muscles and the gluteus maximus during voluntary contractions of the PFMs. Pelvic floor muscle activity was recorded using a vaginal probe during five experimental trials. Activation of transversus abdominis, rectus abdominis, and gluteus maximus during voluntary PFM contractions was also assessed. Significant differences in mean normalized amplitudes of baseline PFM activity were revealed between standing and lying (P < 0.00024) and lying and ball-sitting positions (P < 0.0053). Average peak, average time before peak, and average time after peak did not differ significantly during the voluntary contractions of the PFMs. Baseline PFM activity seemed to depend on the body position and was the highest in standing. Pelvic floor muscles activity during voluntary contractions did not differ by position in continent women. Statistically significant differences between the supine lying and sitting positions were only observed during a sustained 60-second contraction of the PFMs.

  13. [Application of biologically active suture materials in emergency surgery of abdominal cavity organs].

    PubMed

    Mokhov, E M; Chumakov, R Iu; Sergeev, A N

    2012-01-01

    An investigation of specific course of the wound process and near results of operations on 398 patients with emergency abdominal surgical pathology has revealed advantages of using new biologically active suture materials "Nikant" (with doxicyclin) and "Nikant-P" (with doxicyclin and stimulator of regeneration from the group of hermanium-containing organic compounds) in performing surgical interventions. Total number of patients with complications at the early postoperative period, operated using threads "Nikant" (38-29.9%) and "Nikant-P" (30-23.8%) proved to be reliably less than in patients of the control group (71-48.9%). The results of operations improved at the expense of considerable reduction of the number of postoperative local pyo-inflammatory processes.

  14. [Thermoregulatory activity of the intercostal muscles under a hypercapnic load].

    PubMed

    Burachevskaia, L E

    1983-02-01

    In experiments on anesthetized cats, the reactions elicited by CO2 inhalation were studied in single motor units of the intercostal muscles activated during shivering. The excitation of the bulbar respiratory center during shivering was found to modify the activity of the respiratory and tonic motor units. Most of the respiratory motor units in a hypercapnic state increased the mean firing rate by 1.5/sec. The tonic motor units both diminished the mean firing rate and changed the pattern of activity: they began to produce bursts of spikes synchronous with the respiratory rhythm. The problems of supraspinal regulation of activity of the intercostal muscles motoneuron pool are discussed.

  15. Muscle RANK is a key regulator of Ca2+ storage, SERCA activity, and function of fast-twitch skeletal muscles.

    PubMed

    Dufresne, Sébastien S; Dumont, Nicolas A; Boulanger-Piette, Antoine; Fajardo, Val A; Gamu, Daniel; Kake-Guena, Sandrine-Aurélie; David, Rares Ovidiu; Bouchard, Patrice; Lavergne, Éliane; Penninger, Josef M; Pape, Paul C; Tupling, A Russell; Frenette, Jérôme

    2016-04-15

    Receptor-activator of nuclear factor-κB (RANK), its ligand RANKL, and the soluble decoy receptor osteoprotegerin are the key regulators of osteoclast differentiation and bone remodeling. Here we show that RANK is also expressed in fully differentiated myotubes and skeletal muscle. Muscle RANK deletion has inotropic effects in denervated, but not in sham, extensor digitorum longus (EDL) muscles preventing the loss of maximum specific force while promoting muscle atrophy, fatigability, and increased proportion of fast-twitch fibers. In denervated EDL muscles, RANK deletion markedly increased stromal interaction molecule 1 content, a Ca(2+)sensor, and altered activity of the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) modulating Ca(2+)storage. Muscle RANK deletion had no significant effects on the sham or denervated slow-twitch soleus muscles. These data identify a novel role for RANK as a key regulator of Ca(2+)storage and SERCA activity, ultimately affecting denervated skeletal muscle function.

  16. Electromyographic investigation of abdominal exercises and the effects of fatigue.

    PubMed

    Robinson, Mark; Lees, Adrian; Barton, Gabor

    URA muscles but not for the EO (p > 0.05). It was concluded that exercises can be constructed to provide a greater challenge to abdominal muscles, commercially available roller-type equipment appears to be little different from the standard abdominal crunch with bent knees, and fatiguing exercise results in the LRA and URA being more highly activated. These findings provide more detailed knowledge and understanding of the effects of different forms of abdominal exercise.

  17. [Bioelectric activity of paravertebral muscles in experimental scoliosis].

    PubMed

    Gaĭvoronskiĭ, G I; Popov, S V

    1976-12-01

    The paper is concerned with a study of the bioelectrical activity of the paravertebral muscles in 2 groups of rabbits with differently expressed degrees of experimental scoliosis and in a control group of intact animals. The results demonstrated an asymmetry in the tonic bioelectric activity in the paravertebral muscles in scoliosis, unlike the reactions of the control group of animals. The character of asymmetry depends upon the degree of deformation: in cases of moderately expressed scoliosis there is a prevalence of the tonic bioelectric activity on the level of the basic arc of distortion on the side of the concavity; in severely expressed scoliosis the tonic bioelectrical activity of the paravertebral muscles on the concave side appears to be less than on the convex side. An asymmetry of the tonic activity takes place on the level of compensatory arcs as well. The authors come to the conclusion on the pathogenetical role of the muscular dysbalance in the genesis of scoliotic deformation.

  18. Reflex influences on muscle spindle activity in relaxed human leg muscles.

    PubMed

    Gandevia, S C; Miller, S; Aniss, A M; Burke, D

    1986-07-01

    The study was designed to determine whether low-threshold cutaneous and muscle afferents from the foot reflexly activate gamma-motoneurons innervating relaxed muscles of the leg. In 15 experiments multiunit recordings were made from 21 nerve fascicles innervating triceps surae or tibialis anterior. In a further nine experiments the activity of 19 identified single muscle spindle afferents was recorded, 13 from triceps surae, 5 from tibialis anterior, and 1 from extensor digitorum longus. Trains of electrical stimuli (5 stimuli, 300 Hz) were delivered to the sural nerve at the ankle (intensity, twice sensory threshold) and the posterior tibial nerve at the ankle (intensity, 1.1 times motor threshold for the small muscles of the foot). In addition, a tap on the appropriate tendon at varying times after the stimuli was used to assess the dynamic responsiveness of the afferents under study. The conditioning electrical stimuli did not change the discharge of single spindle afferents. Recordings of rectified and averaged multiunit activity also revealed no change in the overall level of background neural activity following the electrical stimuli. The afferent responses to tendon taps did not differ significantly whether or not they were preceded by stimulation of the sural or posterior tibial nerves. These results suggest that low-threshold afferents from the foot do not produce significant activation of fusimotor neurons in relaxed leg muscles, at least as judged by their ability to alter the discharge of muscle spindle afferents. As there may be no effective background activity in fusimotor neurons innervating relaxed human muscles, it is possible that these inputs from the foot could influence the fusimotor system during voluntary contractions when the fusimotor neurons have been brought to firing threshold. In one subject trains of stimuli were delivered to the posterior tibial nerve at painful levels (30 times motor threshold). They produced an acceleration of the

  19. Characterizing differential post-stroke corticomotor drive to the dorsi- and plantarflexor muscles during resting and volitional muscle activation.

    PubMed

    Palmer, Jacqueline Ann; Zarzycki, Ryan; Morton, Susanne M; Kesar, Trisha M; Binder-Macleod, Stuart A

    2017-01-11

    Imbalance of corticomotor excitability between the paretic and nonparetic limbs has been associated with the extent of upper extremity motor recovery post-stroke, is greatly influenced by specific testing conditions such as the presence or absence of volitional muscle activation, and may vary across muscle groups. However, despite its clinical importance, post-stroke corticomotor drive to lower extremity muscles has not been thoroughly investigated. Additionally, while conventional gait rehabilitation strategies for stroke survivors focus on paretic limb foot drop and dorsiflexion impairments, most contemporary literature has indicated that paretic limb propulsion and plantarflexion impairments are the most significant limiters to post-stroke walking function. The purpose of this study was to compare corticomotor excitability of the dorsi- and plantarflexor muscles during resting and active conditions in individuals with good and poor post-stroke walking recovery and in neurologically-intact controls. We found that plantarflexor muscles showed reduced corticomotor symmetry between paretic and nonparetic limbs compared to dorsiflexor muscles in individuals with poor post-stroke walking recovery during active muscle contraction but not during rest. Reduced plantarflexor corticomotor symmetry during active muscle contraction was a result of reduced corticomotor drive to the paretic muscles and enhanced corticomotor drive to the nonparetic muscles when compared to the neurologically-intact controls. These results demonstrate that atypical corticomotor drive exists in both the paretic and nonparetic lower limbs and implicate greater severity of corticomotor impairments to plantarflexor versus dorsiflexor muscles during muscle activation in stroke survivors with poor walking recovery.

  20. Citrus flavonoid, naringenin, increases locomotor activity and reduces diacylglycerol accumulation in skeletal muscle of obese ovariectomized mice

    PubMed Central

    Ke, Jia-Yu; Cole, Rachel M; Hamad, Essam M; Hsiao, Yung-Hsuan; Cotten, Bradley M; Powell, Kimerly A; Belury, Martha A

    2016-01-01

    Scope Estrogen deficiency has been associated with central obesity, muscle loss, and metabolic syndrome in postmenopausal women. This study assessed naringenin accumulation in tissues and investigated the hypothesis that naringenin reverses diet-induced metabolic disturbances in obese ovariectomized mice. Methods and results In study 1, we measured naringenin concentrations in plasma, liver, perigonadal and subcutaneous adipose tissues, and muscle of ovariectomized C57BL/6J female mice after 11 weeks of naringenin supplementation. Naringenin accumulated 5–12 times more in mice fed a 3% naringenin diet than in mice fed a 1% naringenin diet. In study 2, ovariectomized mice were fed a high-fat diet (60 kcal% fat) for 11 weeks and half of the mice were then supplemented with 3% naringenin for another 11 weeks. Dietary naringenin suppressed weight gain, lowered hyperglycemia, and decreased intra-abdominal adiposity evaluated by magnetic resonance imaging. Naringenin-fed mice exhibited elevated locomotor activity monitored by infrared beam breaks, maintained muscle mass, and reduced muscle diacylglycerol content. Real-time PCR analysis in muscle revealed decreased mRNA level for genes involved in de novo lipogenesis, lipolysis, and triglyceride synthesis/storage. Conclusions Long-term 3% naringenin supplementation resulted in significant naringenin accumulation in plasma and tissues, associated with attenuated metabolic dysregulation and muscle loss in obese ovariectomized mice. PMID:26573879

  1. Skeletal Muscle Activity and the Fate of Myonuclei

    PubMed Central

    Turtikova, O.V.; Nemirovskaya, T.L.; Grigoriev, A.I.

    2010-01-01

    Abstract Adult skeletal muscle fiber is a symplast multinuclear structure developed in ontogenesis by the fusion of the myoblasts (muscle progenitor cells). The nuclei of a muscle fiber (myonuclei) are those located at the periphery of fiber in the space between myofibrils and sarcolemma. In theory, a mass change in skeletal muscle during exercise or unloading may be associated with the altered myonuclear number, ratio of the transcription, and translation and proteolysis rates. Here we review the literature data related to the phenomenology and hypothetical mechanisms of the myonuclear number alterations during enhanced or reduced muscle contractile activity. In many cases (during severe muscle and systemic diseases and gravitational unloading), muscle atrophy is accompanied by a reduction in the amount of myonuclei. Such reduction is usually explained by the development of myonuclear apoptosis. A myonuclear number increase may be provided only by the satellite cell nuclei incorporation via cell fusion with the adjacent myofiber. It is believed that it is these cells which supply fiber with additional nuclei, providing postnatal growth, work hypertrophy, and repair processes. Here we discuss the possible mechanisms controlling satellite cell proliferation during exercise, functional unloading, and passive stretch. PMID:22649641

  2. Nerve–muscle activation by rotating permanent magnet configurations

    PubMed Central

    Nicholson, Graham M.

    2016-01-01

    Key points The standard method of magnetic nerve activation using pulses of high current in coils has drawbacks of high cost, high electrical power (of order 1 kW), and limited repetition rate without liquid cooling.Here we report a new technique for nerve activation using high speed rotation of permanent magnet configurations, generating a sustained sinusoidal electric field using very low power (of order 10 W).A high ratio of the electric field gradient divided by frequency is shown to be the key indicator for nerve activation at high frequencies.Activation of the cane toad sciatic nerve and attached gastrocnemius muscle was observed at frequencies as low as 180 Hz for activation of the muscle directly and 230 Hz for curved nerves, but probably not in straight sections of nerve.These results, employing the first prototype device, suggest the opportunity for a new class of small low‐cost magnetic nerve and/or muscle stimulators. Abstract Conventional pulsed current systems for magnetic neurostimulation are large and expensive and have limited repetition rate because of overheating. Here we report a new technique for nerve activation, namely high‐speed rotation of a configuration of permanent magnets. Analytical solutions of the cable equation are derived for the oscillating electric field generated, which has amplitude proportional to the rotation speed. The prototype device built comprised a configuration of two cylindrical magnets with antiparallel magnetisations, made to rotate by interaction between the magnets’ own magnetic field and three‐phase currents in coils mounted on one side of the device. The electric field in a rectangular bath placed on top of the device was both numerically evaluated and measured. The ratio of the electric field gradient on frequency was approximately 1 V m−2 Hz−1 near the device. An exploratory series of physiological tests was conducted on the sciatic nerve and attached gastrocnemius muscle of the cane toad

  3. Effects of Various Types of Situps on Integrated MAP's of the Abdominal Musculature.

    ERIC Educational Resources Information Center

    Noble, Larry

    The electrical activity of the abdominal muscles was tested during situps to determine the effect upon integrated muscle action potential (MAP). The following types of situps were used in testing 18 college males: (1) trunk curls; (2) AAHPER situp; (3) YMCA situp; (4) modified AAHPER situp; and (5) modified YMCA situp. All situps were performed…

  4. Muscle Activity Adaptations to Spinal Tissue Creep in the Presence of Muscle Fatigue

    PubMed Central

    Nougarou, François

    2016-01-01

    Aim The aim of this study was to identify adaptations in muscle activity distribution to spinal tissue creep in presence of muscle fatigue. Methods Twenty-three healthy participants performed a fatigue task before and after 30 minutes of passive spinal tissue deformation in flexion. Right and left erector spinae activity was recorded using large-arrays surface electromyography (EMG). To characterize muscle activity distribution, dispersion was used. During the fatigue task, EMG amplitude root mean square (RMS), median frequency and dispersion in x- and y-axis were compared before and after spinal creep. Results Important fatigue-related changes in EMG median frequency were observed during muscle fatigue. Median frequency values showed a significant main creep effect, with lower median frequency values on the left side under the creep condition (p≤0.0001). A significant main creep effect on RMS values was also observed as RMS values were higher after creep deformation on the right side (p = 0.014); a similar tendency, although not significant, was observed on the left side (p = 0.06). A significant creep effects for x-axis dispersion values was observed, with higher dispersion values following the deformation protocol on the left side (p≤0.001). Regarding y-axis dispersion values, a significant creep x fatigue interaction effect was observed on the left side (p = 0.016); a similar tendency, although not significant, was observed on the right side (p = 0.08). Conclusion Combined muscle fatigue and creep deformation of spinal tissues led to changes in muscle activity amplitude, frequency domain and distribution. PMID:26866911

  5. The effect of muscle length on force depression after active shortening in soleus muscle of mice.

    PubMed

    Van Noten, Pieter; Van Leemputte, Marc

    2011-07-01

    Isometric muscle force after active shortening is reduced [force depression (FD)]. The mechanism is incompletely understood but work delivered during shortening has been suggested to be the main determinant of FD. However, whether muscle length affects the sensitivity of FD to work is unknown, although this information might add to the understanding of the phenomenon. The aim of this study is to investigate the length dependence of the FD/work ratio (Q). Therefore, isometric force production (ISO) of 10 incubated mouse soleus muscles was compared to isometric force after 0.6, 1.2, and 2.4 mm shortening (IAS) at different end lengths ranging from L(0) - 3 to L(0) + 1.8 mm in steps of 0.6 mm. FD was calculated as the force difference between an ISO and IAS contraction at the same activation time (6 s) and end length. We confirm the strong relation between FD and work at L(0) (R² = 0.92) and found that FD is length dependent with a maximum of 8.8 ± 0.3% at L(0) + 1.2 mm for 0.6 mm shortening amplitude. Q was only constant for short muscle lengths (<85% L(0)) but increased exponentially with increasing muscle length. The observed length dependence of Q indicates that FD is not only determined by work produced during shortening but also by a length-dependent factor, possibly actin compliance, which should be incorporated in any mechanism explaining FD.

  6. Whole abdominal wall segmentation using augmented active shape models (AASM) with multi-atlas label fusion and level set

    NASA Astrophysics Data System (ADS)

    Xu, Zhoubing; Baucom, Rebeccah B.; Abramson, Richard G.; Poulose, Benjamin K.; Landman, Bennett A.

    2016-03-01

    The abdominal wall is an important structure differentiating subcutaneous and visceral compartments and intimately involved with maintaining abdominal structure. Segmentation of the whole abdominal wall on routinely acquired computed tomography (CT) scans remains challenging due to variations and complexities of the wall and surrounding tissues. In this study, we propose a slice-wise augmented active shape model (AASM) approach to robustly segment both the outer and inner surfaces of the abdominal wall. Multi-atlas label fusion (MALF) and level set (LS) techniques are integrated into the traditional ASM framework. The AASM approach globally optimizes the landmark updates in the presence of complicated underlying local anatomical contexts. The proposed approach was validated on 184 axial slices of 20 CT scans. The Hausdorff distance against the manual segmentation was significantly reduced using proposed approach compared to that using ASM, MALF, and LS individually. Our segmentation of the whole abdominal wall enables the subcutaneous and visceral fat measurement, with high correlation to the measurement derived from manual segmentation. This study presents the first generic algorithm that combines ASM, MALF, and LS, and demonstrates practical application for automatically capturing visceral and subcutaneous fat volumes.

  7. Whole Abdominal Wall Segmentation using Augmented Active Shape Models (AASM) with Multi-Atlas Label Fusion and Level Set

    PubMed Central

    Xu, Zhoubing; Baucom, Rebeccah B.; Abramson, Richard G.; Poulose, Benjamin K.; Landman, Bennett A.

    2016-01-01

    The abdominal wall is an important structure differentiating subcutaneous and visceral compartments and intimately involved with maintaining abdominal structure. Segmentation of the whole abdominal wall on routinely acquired computed tomography (CT) scans remains challenging due to variations and complexities of the wall and surrounding tissues. In this study, we propose a slice-wise augmented active shape model (AASM) approach to robustly segment both the outer and inner surfaces of the abdominal wall. Multi-atlas label fusion (MALF) and level set (LS) techniques are integrated into the traditional ASM framework. The AASM approach globally optimizes the landmark updates in the presence of complicated underlying local anatomical contexts. The proposed approach was validated on 184 axial slices of 20 CT scans. The Hausdorff distance against the manual segmentation was significantly reduced using proposed approach compared to that using ASM, MALF, and LS individually. Our segmentation of the whole abdominal wall enables the subcutaneous and visceral fat measurement, with high correlation to the measurement derived from manual segmentation. This study presents the first generic algorithm that combines ASM, MALF, and LS, and demonstrates practical application for automatically capturing visceral and subcutaneous fat volumes. PMID:27127333

  8. How I Manage Abdominal Injuries.

    ERIC Educational Resources Information Center

    Haycock, Christine E.

    1986-01-01

    In sports, abdominal injuries occur most frequently in cycling, horseback riding, and skiing. Most involve children, not adults. Any athlete sustaining a severe blow to the abdomen should be examined. Guidelines are provided for recognizing and treating injuries to the abdominal muscles, kidneys, spleen, and liver. (Author/MT)

  9. Relation between low serum cholesteryl-ester transfer activity and abdominal aortic calcification in normolipidemic elderly subjects.

    PubMed

    Miyashita, Y; Morimoto, S; Fukuo, K; Masuyama, T; Yasuda, O; Koh, E; Tamatani, M; Nakahashi, T; Ogihara, T

    1993-01-01

    We studied the relation between cholesteryl-ester transfer activity (CETA) and abdominal aortic calcification in elderly subjects. Compared with 10 young healthy subjects (mean +/- S.D. age, 27 +/-2 years) and to 26 elderly subjects without abdominal aortic calcification (79 +/- 7 years), 16 elderly patients with abdominal aortic calcification (82 +/- 6 years) had significantly lower levels of serum CETA. However, there were no differences in the levels of serum lipids and apolipoproteins, including total cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol and apolipoproteins A-I, A-II, B, C-II and E, between the two elderly groups. When the two groups of elderly subjects were considered together, the level of serum CETA did not correlate significantly with any lipids and apolipoproteins. These results provide evidence that CETA may prevent the development of aortic calcification in normolipidemic elderly people.

  10. The Relationship Between Activity Pattern and Muscle Adaptation in Skeletal Muscle.

    PubMed

    Jarvis, Jonathan C

    2015-10-01

    Muscle is highly plastic in terms of size (maximum force), speed, maximum power, and endurance. Well-controlled studies in animals have shown that the adult skeletal muscle fiber has a remarkable ability to modify its gene expression so that with long-term substantial changes in the daily activity pattern the contractile phenotype can be modified across the whole spectrum of fiber type found in control muscle. The contractile phenotype in this context includes the isoform content of myosin and therefore the maximum velocity of shortening, the mitochondrial content and therefore the specific force and aerobic capacity (endurance), and the calcium handling proteins and therefore the speed of activation and relaxation. With voluntary exercise in human subjects, similar responses are observed, although the degree of transformation is restricted by the practical limitations of exercise dosing to changes in mitochondrial activity and muscle size rather than the more profound changes in contractile protein isoform that can be induced with artificial activation over a substantial proportion of the day.

  11. BRAF activates PAX3 to control muscle precursor cell migration during forelimb muscle development

    PubMed Central

    Shin, Jaeyoung; Watanabe, Shuichi; Hoelper, Soraya; Krüger, Marcus; Kostin, Sawa; Pöling, Jochen; Kubin, Thomas; Braun, Thomas

    2016-01-01

    Migration of skeletal muscle precursor cells is a key step during limb muscle development and depends on the activity of PAX3 and MET. Here, we demonstrate that BRAF serves a crucial function in formation of limb skeletal muscles during mouse embryogenesis downstream of MET and acts as a potent inducer of myoblast cell migration. We found that a fraction of BRAF accumulates in the nucleus after activation and endosomal transport to a perinuclear position. Mass spectrometry based screening for potential interaction partners revealed that BRAF interacts and phosphorylates PAX3. Mutation of BRAF dependent phosphorylation sites in PAX3 impaired the ability of PAX3 to promote migration of C2C12 myoblasts indicating that BRAF directly activates PAX3. Since PAX3 stimulates transcription of the Met gene we propose that MET signaling via BRAF fuels a positive feedback loop, which maintains high levels of PAX3 and MET activity required for limb muscle precursor cell migration. DOI: http://dx.doi.org/10.7554/eLife.18351.001 PMID:27906130

  12. Muscle triacylglycerol and hormone-sensitive lipase activity in untrained and trained human muscles.

    PubMed

    Helge, Jørn Wulff; Biba, Taus O; Galbo, Henrik; Gaster, Michael; Donsmark, Morten

    2006-07-01

    During exercise, triacylglycerol (TG) is recruited in skeletal muscles. We hypothesized that both muscle hormone-sensitive lipase (HSL) activity and TG recruitment would be higher in trained than in untrained subjects in response to prolonged exercise. Healthy male subjects (26 +/- 1 years, body moss index 23.3 +/- 0.5 kg m(-2)), either untrained (N = 8, VO(2max) 3.8 +/- 0.2 l min(-1)) or trained (N = 8, VO(2max) 5.1 +/- 0.1 l min(-1)), were studied. Before and after 3-h exercise (58 +/- 1% VO(2max)), a biopsy was taken. Muscle citrate synthase (32 +/- 2 vs. 47 +/- 6 mumol g(-1) min(-1) d.w.) and beta-hydroxy-acyl-CoA-dehydrogenase (38 +/- 3 vs. 52 +/- 5 mumol g(-1) min(-1) d.w.) activities were lower in untrained than in trained subjects (p < 0.05). Throughout the exercise, fat oxidation was higher in trained than in untrained subjects (p < 0.05). Muscle HSL activity was similar at rest (0.72 +/- 0.08 and 0.74 +/- 0.03 mU mg(-1) protein) and after exercise (0.71 +/- 0.1 and 0.68 +/- 0.03 mU mg(-1) protein) in untrained and trained subjects. At rest, the chemically determined muscle TG content (37 +/- 8 and 26 +/- 5 mmol g(-1) d.w.) was similar (p > 0.05), and after exercise it was unchanged in untrained and lower (p < 0.05) in trained subjects (41 +/- 9 and 10 +/- 2 mmol g((1) d.w.). Determined histochemically, TG was decreased (p < 0.05) after exercise in type I and II fibres. Depletion of TG was not different between fibre types in untrained, but tended to be higher (p = 0.07) in type I compared with type II fibres in trained muscles. In conclusion, HSL activity is similar in untrained and trained skeletal muscles both before and after prolonged exercise. However, the tendency to higher muscle TG recruitment during exercise in the trained subjects suggests a difference in the regulation of HSL or other lipases during exercise in trained compared with untrained subjects.

  13. Weakness of the Pelvic Floor Muscle and Bladder Neck Is Predicted by a Slight Rise in Abdominal Pressure During Bladder Filling: A Video Urodynamic Study in Children

    PubMed Central

    2016-01-01

    Purpose: To investigate the significance of slowly rising abdominal pressure (SRAP), which is often observed in nonneurogenic children during bladder filling in video urodynamic studies (VUDSs). Methods: The records of patients who underwent VUDS from July 2011 to June 2013 were reviewed. SRAP was defined as a rising curve over 5 cm H2O from the baseline abdominal pressure during the filling phase in VUDS. Bladder descent was defined when the base of the bladder was below the upper line of the pubic symphysis. An open bladder neck was defined as the opening of the bladder neck during the filling phase. Results: Of the 488 patients, 285 were male patients. The mean age at VUDS was 3.7 years (range, 0.2–17.6 years). The VUDS findings were as follows: SRAP, 20.7% (101 of 488); descending bladder, 14.8% (72 of 488); and bladder neck opening, 4.3% (21 of 488). Of the 72 patients with a descending bladder, 84.7% had SRAP. A significant difference in the presence of SRAP was found between the descending bladder and the normal bladder (P<0.001). Of the 101 patients with SRAP, 40 (39.6%) did not have a descending bladder. Of the 40 patients, 14 (35.0%) had a bladder neck opening, which was a high incidence compared with the 4.3% in all subjects (P<0.001). Conclusions: SRAP was associated with a descending bladder or a bladder neck opening, suggesting that SRAP is a compensatory response to urinary incontinence. SRAP may also predict decreased function of the bladder neck or pelvic floor muscle. PMID:27032558

  14. Contributions of Central Command and Muscle Feedback to Sympathetic Nerve Activity in Contracting Human Skeletal Muscle

    PubMed Central

    Boulton, Daniel; Taylor, Chloe E.; Macefield, Vaughan G.; Green, Simon

    2016-01-01

    During voluntary contractions, muscle sympathetic nerve activity (MSNA) to contracting muscles increases in proportion to force but the underlying mechanisms are not clear. To shed light on these mechanisms, particularly the influences of central command and muscle afferent feedback, the present study tested the hypothesis that MSNA is greater during voluntary compared with electrically-evoked contractions. Seven male subjects performed a series of 1-min isometric dorsiflexion contractions (left leg) separated by 2-min rest periods, alternating between voluntary and electrically-evoked contractions at similar forces (5–10% of maximum). MSNA was recorded continuously (microneurography) from the left peroneal nerve and quantified from cardiac-synchronized, negative-going spikes in the neurogram. Compared with pre-contraction values, MSNA increased by 51 ± 34% (P < 0.01) during voluntary contractions but did not change significantly during electrically-evoked contractions (−8 ± 12%, P > 0.05). MSNA analyzed at 15-s intervals revealed that this effect of voluntary contraction appeared 15–30 s after contraction onset (P < 0.01), remained elevated until the end of contraction, and disappeared within 15 s after contraction. These findings suggest that central command, and not feedback from contracting muscle, is the primary mechanism responsible for the increase in MSNA to contracting muscle. The time-course of MSNA suggests that there is a longer delay in the onset of this effect compared with its cessation after contraction. PMID:27242537

  15. Grip force and muscle activity differences due to glove type.

    PubMed

    Kovacs, Kimberly; Splittstoesser, Riley; Maronitis, Anthony; Marras, William S

    2002-01-01

    The purpose of this study was to investigate the effects of different types and sizes of gloves on external grip force and muscle activity. Twenty-one male and seven female volunteers served as subjects. Each subject performed two maximum voluntary grip contractions while wearing each of the 10 glove types. Results indicated significant differences in the effects of different glove types on the peak force, ratio of peak force to normalized flexor muscle EMG activity, and the ratio of peak force to coactivity.

  16. Prior history of FDI muscle contraction: different effect on MEP amplitude and muscle activity.

    PubMed

    Talis, V L; Kazennikov, O V; Castellote, J M; Grishin, A A; Ioffe, M E

    2014-03-01

    Motor evoked potentials (MEPs) in the right first dorsal interosseous (FDI) muscle elicited by transcranial magnetic stimulation of left motor cortex were assessed in ten healthy subjects during maintenance of a fixed FDI contraction level. Subjects maintained an integrated EMG (IEMG) level with visual feedback and reproduced this level by memory afterwards in the following tasks: stationary FDI muscle contraction at the level of 40 ± 5 % of its maximum voluntary contraction (MVC; 40 % task), at the level of 20 ± 5 % MVC (20 % task), and also when 20 % MVC was preceded by either no contraction (0-20 task), by stronger muscle contraction (40-20 task) or by no contraction with a previous strong contraction (40-0-20 task). The results show that the IEMG level was within the prescribed limits when 20 and 40 % stationary tasks were executed with and without visual feedback. In 0-20, 40-20, and 40-0-20 tasks, 20 % IEMG level was precisely controlled in the presence of visual feedback, but without visual feedback the IEMG and force during 20 % IEMG maintenance were significantly higher in the 40-0-20 task than those in 0-20 and 40-20 tasks. That is, without visual feedback, there were significant variations in muscle activity due to different prehistory of contraction. In stationary tasks, MEP amplitudes in 40 % task were higher than in 20 % task. MEPs did not differ significantly during maintenance of the 20 % level in tasks with different prehistory of muscle contraction with and without visual feedback. Thus, in spite of variations in muscle background activity due to different prehistory of contraction MEPs did not vary significantly. This dissociation suggests that the voluntary maintenance of IEMG level is determined not only by cortical mechanisms, as reflected by corticospinal excitability, but also by lower levels of CNS, where afferent signals and influences from other brain structures and spinal cord are convergent.

  17. Abdominal ultrasound

    MedlinePlus

    ... Kidney - blood and urine flow Abdominal ultrasound References Chen L. Abdominal ultrasound imaging. In: Sahani DV, Samir ... the Health on the Net Foundation (www.hon.ch). The information provided herein should not be used ...

  18. Abdominal tap

    MedlinePlus

    ... tap; Cirrhosis - abdominal tap; Malignant ascites - abdominal tap Images Digestive system Peritoneal sample References Garcia-Tiso G. ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  19. Optimization of Spinal Muscular Atrophy subject's muscle activity during gait

    NASA Astrophysics Data System (ADS)

    Umat, Gazlia; Rambely, Azmin Sham

    2014-06-01

    Spinal Muscular Atrophy (SMA) is a hereditary disease related muscle nerve disorder caused by degeneration of the anterior cells of the spinal cord. SMA is divided into four types according to the degree of seriousness. SMA patients show different gait with normal people. Therefore, this study focused on the effects of SMA patient muscle actions and the difference that exists between SMA subjects and normal subjects. Therefore, the electromyography (EMG) test will be used to track the behavior of muscle during walking and optimization methods are used to get the muscle stress that is capable of doing the work while walking. Involved objective function is non-linear function of the quadratic and cubic functions. The study concludes with a comparison of the objective function using the force that sought to use the moment of previous studies and the objective function using the data obtained from EMG. The results shows that the same muscles, peroneus longus and bisepsfemoris, were used during walking activity by SMA subjects and control subjects. Muscle stress force best solution achieved from part D in simulation carried out.

  20. Multivariable Dynamic Ankle Mechanical Impedance With Active Muscles

    PubMed Central

    Lee, Hyunglae; Krebs, Hermano Igo; Hogan, Neville

    2015-01-01

    Multivariable dynamic ankle mechanical impedance in two coupled degrees-of-freedom (DOFs) was quantified when muscles were active. Measurements were performed at five different target activation levels of tibialis anterior and soleus, from 10% to 30% of maximum voluntary contraction (MVC) with increments of 5% MVC. Interestingly, several ankle behaviors characterized in our previous study of the relaxed ankle were observed with muscles active: ankle mechanical impedance in joint coordinates showed responses largely consistent with a second-order system consisting of inertia, viscosity, and stiffness; stiffness was greater in the sagittal plane than in the frontal plane at all activation conditions for all subjects; and the coupling between dorsiflexion–plantarflexion and inversion–eversion was small—the two DOF measurements were well explained by a strictly diagonal impedance matrix. In general, ankle stiffness increased linearly with muscle activation in all directions in the 2-D space formed by the sagittal and frontal planes, but more in the sagittal than in the frontal plane, resulting in an accentuated “peanut shape.” This characterization of young healthy subjects’ ankle mechanical impedance with active muscles will serve as a baseline to investigate pathophysiological ankle behaviors of biomechanically and/or neurologically impaired patients. PMID:25203497

  1. The effect of muscle activation on neck response.

    PubMed

    Brolin, Karin; Halldin, Peter; Leijonhufvud, Ingrid

    2005-03-01

    Prevention of neck injuries due to complex loading, such as occurs in traffic accidents, requires knowledge of neck injury mechanisms and tolerances. The influence of muscle activation on outcome of the injuries is not clearly understood. Numerical simulations of neck injury accidents can contribute to increase the understanding of injury tolerances. The finite element (FE) method is suitable because it gives data on stress and strain of individual tissues that can be used to predict injuries based on tissue level criteria. The aim of this study was to improve and validate an anatomically detailed FE model of the human cervical spine by implement neck musculature with passive and active material properties. Further, the effect of activation time and force on the stresses and strains in the cervical tissues were studied for dynamic loading due to frontal and lateral impacts. The FE model used includes the seven cervical vertebrae, the spinal ligaments, the facet joints with cartilage, the intervertebral disc, the skull base connected to a rigid head, and a spring element representation of the neck musculature. The passive muscle properties were defined with bilinear force-deformation curves and the active properties were defined using a material model based on the Hill equation. The FE model's responses were compared to volunteer experiments for frontal and lateral impacts of 15 and 7 g. Then, the active muscle properties where varied to study their effect on the motion of the skull, the stress level of the cortical and trabecular bone, and the strain of the ligaments. The FE model had a good correlation to the experimental motion corridors when the muscles activation was implemented. For the frontal impact a suitable peak muscle force was 40 N/cm2 whereas 20 N/cm2 was appropriate for the side impact. The stress levels in the cortical and trabecular bone were influenced by the point forces introduced by the muscle spring elements; therefore a more detailed model of

  2. Abdominal Pain

    MedlinePlus

    ... call your doctor. In Spanish— Dolor abdominal en niños menores de 12 años What is recurrent abdominal ... Functional abdominal pain (FAP) typically affects kids ages 4-12, and is quite common, affecting up to ...

  3. Variability and reliability of muscle activity measurements during chewing.

    PubMed

    Kravchenko, A; Weiser, A; Hugger, S; Kordass, B; Hugger, A; Wanke, E

    2014-01-01

    The objective of this study was to test masseter muscle activity and its variability and reliability in terms of repeatable measurements in fully dentate and healthy volunteers during habitual chewing and deliberate unilateral chewing. Three sessions were performed on three consecutive days, each time recording kinematic data and masseter muscle EMG activities through a series of defined jaw exercises, including maximum voluntary contraction, habitual chewing, and left and right unilateral chewing. Asymmetry index (AI) and deliberate chewing index (DCI) scores were used to evaluate the activities of the left and right masseter muscles, which were separately recorded during each of these chewing exercises. DCI scores were side-specific, including two sets of values for left and right unilateral chewing. Reproducibility testing of the values obtained for all parameters revealed good to excellent reproducibility of masseter muscle activity under standardized recording conditions across the consecutive study sessions, with intra-class correlation coefficients (ICCs) ranging from 0.68 to 0.93. Different individuals were found to utilize different strategies of bilateral masseter activation during both habitual chewing and deliberate unilateral chewing.

  4. Task-dependent effects evoked by foot muscle afferents on leg muscle activity in humans.

    PubMed

    Abbruzzese, M; Rubino, V; Schieppati, M

    1996-08-01

    The effect of low intensity electrical stimulation of the posterior tibial nerve (PTN) at the ankle on the active triceps surae (TS) muscles was studied in normal subjects, both in a prone position and while standing. PTN stimulation regularly evoked the H-reflex in the flexor digitorum brevis and, in the prone position, a short-latency facilitatory effect in the soleus muscle. During standing, the facilitatory effect was preceded by a clear-cut reduction in electromyograph (EMG) activity. The inhibition-facilitation sequence was evoked in the gastrocnemii under both conditions, on average, though individual differences were present. An EMG modulation similar to that observed under standing conditions was present also in the prone position when subjects pressed the sole of the foot against the wall. Stimulation of sural or digital nerves did not evoke similar effects. It is concluded that foot muscle afferents establish oligosynaptic connections transmitting mixed effects to the TS motoneuronal pool, and that contact with the sole of the foot plays an enabling role for the inhibitory pathway directed to the soleus muscle.

  5. The mechanical actions of muscles predict the direction of muscle activation during postural perturbations in the cat hindlimb

    PubMed Central

    Nichols, T. Richard

    2013-01-01

    Humans and cats respond to balance challenges, delivered via horizontal support surface perturbations, with directionally selective muscle recruitment and constrained ground reaction forces. It has been suggested that this postural strategy arises from an interaction of limb biomechanics and proprioceptive networks in the spinal cord. A critical experimental validation of this hypothesis is to test the prediction that the principal directions of muscular activation oppose the directions responding muscles exert their forces on the environment. Therefore, our objective was to quantify the endpoint forces of a diverse set of cat hindlimb muscles and compare them with the directionally sensitive muscle activation patterns generated in the intact and decerebrate cat. We hypothesized that muscles are activated based on their mechanical advantage. Our primary expectation was that the principal direction of muscle activation during postural perturbations will be directed oppositely (180°) from the muscle endpoint ground reaction force. We found that muscle activation during postural perturbations was indeed directed oppositely to the endpoint reaction forces of that muscle. These observations indicate that muscle recruitment during balance challenges is driven, at least in part, by limb architecture. This suggests that sensory sources that provide feedback about the mechanical environment of the limb are likely important to appropriate and effective responses during balance challenges. Finally, we extended the analysis to three dimensions and different stance widths, laying the groundwork for a more comprehensive study of postural regulation than was possible with measurements confined to the horizontal plane and a single stance configuration. PMID:24304861

  6. The mechanical actions of muscles predict the direction of muscle activation during postural perturbations in the cat hindlimb.

    PubMed

    Honeycutt, Claire F; Nichols, T Richard

    2014-03-01

    Humans and cats respond to balance challenges, delivered via horizontal support surface perturbations, with directionally selective muscle recruitment and constrained ground reaction forces. It has been suggested that this postural strategy arises from an interaction of limb biomechanics and proprioceptive networks in the spinal cord. A critical experimental validation of this hypothesis is to test the prediction that the principal directions of muscular activation oppose the directions responding muscles exert their forces on the environment. Therefore, our objective was to quantify the endpoint forces of a diverse set of cat hindlimb muscles and compare them with the directionally sensitive muscle activation patterns generated in the intact and decerebrate cat. We hypothesized that muscles are activated based on their mechanical advantage. Our primary expectation was that the principal direction of muscle activation during postural perturbations will be directed oppositely (180°) from the muscle endpoint ground reaction force. We found that muscle activation during postural perturbations was indeed directed oppositely to the endpoint reaction forces of that muscle. These observations indicate that muscle recruitment during balance challenges is driven, at least in part, by limb architecture. This suggests that sensory sources that provide feedback about the mechanical environment of the limb are likely important to appropriate and effective responses during balance challenges. Finally, we extended the analysis to three dimensions and different stance widths, laying the groundwork for a more comprehensive study of postural regulation than was possible with measurements confined to the horizontal plane and a single stance configuration.

  7. Tirasemtiv amplifies skeletal muscle response to nerve activation in humans

    PubMed Central

    Hansen, Richard; Saikali, Khalil G; Chou, Willis; Russell, Alan J; Chen, Michael M; Vijayakumar, Vipin; Stoltz, Randall R; Baudry, Stephane; Enoka, Roger M; Morgans, David J; Wolff, Andrew A; Malik, Fady I

    2014-01-01

    Introduction: In this study we tested the hypothesis that tirasemtiv, a selective fast skeletal muscle troponin activator that sensitizes the sarcomere to calcium, could amplify the response of muscle to neuromuscular input in humans. Methods: Healthy men received tirasemtiv and placebo in a randomized, double-blind, 4-period, crossover design. The deep fibular nerve was stimulated transcutaneously to activate the tibialis anterior muscle and produce dorsiflexion of the foot. The force–frequency relationship of tibialis anterior dorsiflexion was assessed after dosing. Results: Tirasemtiv increased force produced by the tibialis anterior in a dose-, concentration-, and frequency-dependent manner with the largest increases [up to 24.5% (SE 3.1), P < 0.0001] produced at subtetanic nerve stimulation frequencies (10 Hz). Conclusions: The data confirm that tirasemtiv amplifies the response of skeletal muscle to nerve input in humans. This outcome provides support for further studies of tirasemtiv as a potential therapy in conditions marked by diminished neuromuscular input. Muscle Nerve 50: 925–931, 2014 PMID:24634285

  8. A dynamical model of muscle activation, fatigue, and recovery.

    PubMed Central

    Liu, Jing Z; Brown, Robert W; Yue, Guang H

    2002-01-01

    A dynamical model is presented as a framework for muscle activation, fatigue, and recovery. By describing the effects of muscle fatigue and recovery in terms of two phenomenological parameters (F, R), we develop a set of dynamical equations to describe the behavior of muscles as a group of motor units activated by voluntary effort. This model provides a macroscopic view for understanding biophysical mechanisms of voluntary drive, fatigue effect, and recovery in stimulating, limiting, and modulating the force output from muscles. The model is investigated under the condition in which brain effort is assumed to be constant. Experimental validation of the model is performed by fitting force data measured from healthy human subjects during a 3-min sustained maximal voluntary handgrip contraction. The experimental results confirm a theoretical inference from the model regarding the possibility of maximal muscle force production, and suggest that only 97% of the true maximal force can be reached under maximal voluntary effort, assuming that all motor units can be recruited voluntarily. The effects of different motor unit types, time-dependent brain effort, sources of artifacts, and other factors that could affect the model are discussed. The applications of the model are also discussed. PMID:11964225

  9. [Latest standards of muscle injury prophylactic activities, treatment and rehabilitation].

    PubMed

    Jaroszewski, Jacek; Bakowski, Paweł; Tabiszewski, Maciej

    2008-01-01

    Muscle injury represents the highest proportion of sport-linked contusions. Experimental and clinical studies aim at increasingly detailed recognition of muscle physiology and pathophysiology. It would allow to set up functional standards and permit to minimize risk of contusions associated with sport activities. In cases of such contusions it would restrict its sequele and would abbreviate the duration of treatment. In the study elements of prophylaxis, treatment and rehabilitation of injured muscles will be discussed, based on current scientific results. Review study includes data from studies investigating prophylactic activities, types of teratment and the effects of different rehabilitation strategy. Latest standards from First European Congress of Football Medicine, Munich 2004, were also taken into account. The prophylactic activities should focus on education attempting to popularize the knowledge of the role of warm-up activities which precede proper physical effort, muscle stretching and activities augmenting muscle strength. The treatment of muscle injury is related to the extent of their damage. First actions should be focused on the RICE principle (Rest, Ice, Compression, Elevation). In case of torn tissues, local injections of anesthetics, anti-inflammatory agents and regeneration-promoting agents used to be applied. Application of NSAIDs and anti-thrombotic prophylaxis is sound but due to their side effects it is recommended as frequently as it is counterindicated by physicians. A threshold in the therapy, not always noted by therapeutists, involves rapid mobilization of the injured tissue. This involves mobility exercises starting at 3-5 days post-trauma, with no load at the beginning, but starting at days 4 to 6 asssociated with appropriate loading. The recently conducted studies aim at stimulation of rapid muscle regeneration, inhibition of scar formation in the site of injury and elimination of already existing scars. The latter seems most

  10. Assessing voluntary muscle activation with the twitch interpolation technique.

    PubMed

    Shield, Anthony; Zhou, Shi

    2004-01-01

    The twitch interpolation technique is commonly employed to assess the completeness of skeletal muscle activation during voluntary contractions. Early applications of twitch interpolation suggested that healthy human subjects could fully activate most of the skeletal muscles to which the technique had been applied. More recently, however, highly sensitive twitch interpolation has revealed that even healthy adults routinely fail to fully activate a number of skeletal muscles despite apparently maximal effort. Unfortunately, some disagreement exists as to how the results of twitch interpolation should be employed to quantify voluntary activation. The negative linear relationship between evoked twitch force and voluntary force that has been observed by some researchers implies that voluntary activation can be quantified by scaling a single interpolated twitch to a control twitch evoked in relaxed muscle. Observations of non-linear evoked-voluntary force relationships have lead to the suggestion that the single interpolated twitch ratio can not accurately estimate voluntary activation. Instead, it has been proposed that muscle activation is better determined by extrapolating the relationship between evoked and voluntary force to provide an estimate of true maximum force. However, criticism of the single interpolated twitch ratio typically fails to take into account the reasons for the non-linearity of the evoked-voluntary force relationship. When these reasons are examined, it appears that most are even more challenging to the validity of extrapolation than they are to the linear equation. Furthermore, several factors that contribute to the observed non-linearity can be minimised or even eliminated with appropriate experimental technique. The detection of small activation deficits requires high resolution measurement of force and careful consideration of numerous experimental details such as the site of stimulation, stimulation intensity and the number of interpolated

  11. Orofacial Muscle Activity of Children Who Stutter: A Preliminary Study.

    ERIC Educational Resources Information Center

    Kelly, Ellen M.; And Others

    1995-01-01

    This preliminary investigation of stuttering development and maturation of speech motor processes recorded the electromyographic activity of the orofacial muscles of nine children who stuttered. Results suggest that the emergence of tremor-like instabilities in the speech motor processes of stuttering children may coincide with aspects of general…

  12. Nutritional strategies of physically active subjects with muscle dysmorphia

    PubMed Central

    2013-01-01

    Background The aim of this study was to identify dietary strategies for physically active individuals with muscle dysmorphia based on a systematic literature review. Method References were included if the study population consisted of adults over 18 years old who were physically active in fitness centers. We identified reports through an electronic search ofScielo, Lilacs and Medline using the following keywords: muscle dysmorphia, vigorexia, distorted body image, and exercise. We found eight articles in Scielo, 17 in Medline and 12 in Lilacs. Among the total number of 37 articles, only 17 were eligible for inclusion in this review. Results The results indicated that the feeding strategies used by physically active individuals with muscle dysmorphia did not include planning or the supervision of a nutritionist. Diet included high protein and low fat foods and the ingestion of dietary and ergogenic supplements to reduce weight. Conclusion Physically active subjects with muscle dysmorphia could benefit from the help of nutritional professionals to evaluate energy estimation, guide the diet and its distribution in macronutrient and consider the principle of nutrition to functional recovery of the digestive process, promote liver detoxification, balance and guide to organic adequate intake of supplemental nutrients and other substances. PMID:23706013

  13. Mapping Muscles Activation to Force Perception during Unloading

    PubMed Central

    Toma, Simone; Lacquaniti, Francesco

    2016-01-01

    It has been largely proved that while judging a force humans mainly rely on the motor commands produced to interact with that force (i.e., sense of effort). Despite of a large bulk of previous investigations interested in understanding the contributions of the descending and ascending signals in force perception, very few attempts have been made to link a measure of neural output (i.e., EMG) to the psychophysical performance. Indeed, the amount of correlation between EMG activity and perceptual decisions can be interpreted as an estimate of the contribution of central signals involved in the sensation of force. In this study we investigated this correlation by measuring the muscular activity of eight arm muscles while participants performed a quasi-isometric force detection task. Here we showed a method to quantitatively describe muscular activity (“muscle-metric function”) that was directly comparable to the description of the participants' psychophysical decisions about the stimulus force. We observed that under our experimental conditions, muscle-metric absolute thresholds and the shape of the muscle-metric curves were closely related to those provided by the psychophysics. In fact a global measure of the muscles considered was able to predict approximately 60% of the perceptual decisions total variance. Moreover the inter-subjects differences in psychophysical sensitivity showed high correlation with both participants' muscles sensitivity and participants' joint torques. Overall, our findings gave insights into both the role played by the corticospinal motor commands while performing a force detection task and the influence of the gravitational muscular torque on the estimation of vertical forces. PMID:27032087

  14. Changes in Quadriceps Muscle Activity During Sustained Recreational Alpine Skiing

    PubMed Central

    Kröll, Josef; Müller, Erich; Seifert, John G.; Wakeling, James M.

    2011-01-01

    During a day of skiing thousands of repeated contractions take place. Previous research on prolonged recreational alpine skiing show that physiological changes occur and hence some level of fatigue is inevitable. In the present paper the effect of prolonged skiing on the recruitment and coordination of the muscle activity was investigated. Six subjects performed 24 standardized runs. Muscle activity during the first two (PREskiing) and the last two (POSTskiing) runs was measured from the vastus lateralis (VL) and rectus femoris (RF) using EMG and quantified using wavelet and principal component analysis. The frequency content of the EMG signal shifted in seven out of eight cases significantly towards lower frequencies with highest effects observed for RF on outside leg. A significant pronounced outside leg loading occurred during POSTskiing and the timing of muscle activity peaks occurred more towards turn completion. Specific EMG frequency changes were observed at certain time points throughout the time windows and not over the whole double turn. It is suggested that general muscular fatigue, where additional specific muscle fibers have to be recruited due to the reduced power output of other fibers did not occur. The EMG frequency decrease and intensity changes for RF and VL are caused by altered timing (coordination) within the turn towards a most likely more uncontrolled skiing technique. Hence, these data provide evidence to suggest recreational skiers alter their skiing technique before a potential change in muscle fiber recruitment occurs. Key points The frequency content of the EMG signal shifted in seven out of eight cases significantly towards lower frequencies with highest effects observed for RF. General muscular fatigue, where additional specific fibers have to be recruited due to the reduced power output of other fibers, did not occur. A modified skiing style towards a less functional and hence more uncontrolled skiing technique seems to be a key

  15. Cell-Activation by Shear Stresses in Abdominal Aortic Aneurysms (AAA)

    NASA Astrophysics Data System (ADS)

    Salsac, Anne-Virginie; Sparks, Steven; Chomaz, Jean-Marc; Lasheras, Juan C.

    2003-11-01

    Increasing experimental evidence indicates that low and oscillatory shear stresses promote proliferative, thrombotic, adhesive and inflammatory-mediated degenerative conditions throughout the wall of the aorta. These degenerative conditions have been shown to be involved in the pathogenesis of AAAs, a permanent, localized dilatation of the abdominal aorta. The purpose of this study is to measure both the magnitude and the duration of the shear stresses acting on both the arterial walls and on the blood cells inside AAAs, and to characterize their changes as the AAA enlarges. We conducted a parametric in-vitro study of the pulsatile blood flow in elastic models of AAAs while systematically varying the blood flow parameters, and the geometry of the aneurysm's bulging. The instantaneous flow characteristic inside the AAA was measured using DPIV at a sampling rate of 15 Hertz. A "cell-activation parameter" defined as the integral of the product of the magnitude of the shear stress and the time during which the stress acts was computed along each of the blood cell pathlines. The Lagrangian tracking of the blood cells shows that a large majority of them are subjected first to very high level of shear-induced "cell-activation" while later on they are entrained in regions of stasis where their residence time can increase up to several cardiac cycles. This cell-activation followed by the entrainment in low shear regions creates the optimal cell-adhesive and inflammatory-mediated degenerative conditions that are postulated to play an important role in the etiology and progressive enlargement of AAAs.

  16. 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.

  17. Factors modifying the frequency of spontaneous activity in gastric muscle.

    PubMed

    Suzuki, H; Kito, Y; Hashitani, H; Nakamura, E

    2006-11-01

    The cellular mechanisms that determine the frequency of spontaneous activity were investigated in gastric smooth muscles isolated from the guinea-pig. Intact antral muscle generated slow waves periodically; the interval between slow waves was decreased exponentially by depolarization of the membrane to reach a steady interval value of about 7 s. Isolated circular muscle bundles produced slow potentials spontaneously or were evoked by depolarizing current stimuli. Evoked slow potentials appeared in an all-or-none fashion, with a refractory period of approximately 2-3 s. Low concentrations of chemicals that modify intracellular signalling revealed that the refractory period was causally related to the activity of protein kinase C (PKC). Activation of PKC increased and inhibition of PKC activity decreased the frequency of slow potentials. Chemicals that inhibit mitochondrial functions reduced the frequency of slow waves. Inhibition of internal Ca(2+)-store activity decreased the amplitude, but not the frequency of slow potentials, suggesting that the amplitude is causally related to Ca(2+) release from the internal store. The results suggest that changes in [Ca(2+)](i) caused by the activity of mitochondria may play a key role in determining the frequency of spontaneous activity in gastric pacemaker cells.

  18. Genetically enhancing mitochondrial antioxidant activity improves muscle function in aging.

    PubMed

    Umanskaya, Alisa; Santulli, Gaetano; Xie, Wenjun; Andersson, Daniel C; Reiken, Steven R; Marks, Andrew R

    2014-10-21

    Age-related skeletal muscle dysfunction is a leading cause of morbidity that affects up to half the population aged 80 or greater. Here we tested the effects of increased mitochondrial antioxidant activity on age-dependent skeletal muscle dysfunction using transgenic mice with targeted overexpression of the human catalase gene to mitochondria (MCat mice). Aged MCat mice exhibited improved voluntary exercise, increased skeletal muscle specific force and tetanic Ca(2+) transients, decreased intracellular Ca(2+) leak and increased sarcoplasmic reticulum (SR) Ca(2+) load compared with age-matched wild type (WT) littermates. Furthermore, ryanodine receptor 1 (the sarcoplasmic reticulum Ca(2+) release channel required for skeletal muscle contraction; RyR1) from aged MCat mice was less oxidized, depleted of the channel stabilizing subunit, calstabin1, and displayed increased single channel open probability (Po). Overall, these data indicate a direct role for mitochondrial free radicals in promoting the pathological intracellular Ca(2+) leak that underlies age-dependent loss of skeletal muscle function. This study harbors implications for the development of novel therapeutic strategies, including mitochondria-targeted antioxidants for treatment of mitochondrial myopathies and other healthspan-limiting disorders.

  19. Ion channel activity in lobster skeletal muscle membrane.

    PubMed

    Worden, M K; Rahamimoff, R; Kravitz, E A

    1993-09-01

    Ion channel activity in the sarcolemmal membrane of muscle fibers is critical for regulating the excitability, and therefore the contractility, of muscle. To begin the characterization of the biophysical properties of the sarcolemmal membrane of lobster exoskeletal muscle fibers, recordings were made from excised patches of membrane from enzymatically induced muscle fiber blebs. Blebs formed as evaginations of the muscle sarcolemmal membrane and were sufficiently free of extracellular debris to allow the formation of gigaohm seals. Under simple experimental conditions using bi-ionic symmetrical recording solutions and maintained holding potentials, a variety of single channel types with conductances in the range 32-380 pS were detected. Two of these ion channel species are described in detail, both are cation channels selective for potassium. They can be distinguished from each other on the basis of their single-channel conductance and gating properties. The results suggest that current flows through a large number of ion channels that open spontaneously in bleb membranes in the absence of exogenous metabolites or hormones.

  20. Non-crossbridge stiffness in active muscle fibres.

    PubMed

    Colombini, Barbara; Nocella, Marta; Bagni, Maria Angela

    2016-01-01

    Stretching of an activated skeletal muscle induces a transient tension increase followed by a period during which the tension remains elevated well above the isometric level at an almost constant value. This excess of tension in response to stretching has been called 'static tension' and attributed to an increase in fibre stiffness above the resting value, named 'static stiffness'. This observation was originally made, by our group, in frog intact muscle fibres and has been confirmed more recently, by us, in mammalian intact fibres. Following stimulation, fibre stiffness starts to increase during the latent period well before crossbridge force generation and it is present throughout the whole contraction in both single twitches and tetani. Static stiffness is dependent on sarcomere length in a different way from crossbridge force and is independent of stretching amplitude and velocity. Static stiffness follows a time course which is distinct from that of active force and very similar to the myoplasmic calcium concentration time course. We therefore hypothesize that static stiffness is due to a calcium-dependent stiffening of a non-crossbridge sarcomere structure, such as the titin filament. According to this hypothesis, titin, in addition to its well-recognized role in determining the muscle passive tension, could have a role during muscle activity.

  1. Neck and shoulder muscle activity of orthodontists in natural environments.

    PubMed

    McNee, C; Kieser, J K; Antoun, J S; Bennani, H; Gallo, L M; Farella, M

    2013-06-01

    Work related musculoskeletal disorders (WMSDs) are common among dentists and possibly caused by prolonged static load. The aim of this study was to assess the contraction pattern of neck and shoulder muscles of orthodontists in natural environments. Electromyographic (EMG) activity of right sternocleidomastoid and trapezius muscles were recorded by means of portable recorders in eight orthodontists during working conditions, and both active and resting non-working conditions. Recordings were analysed in terms of contraction episode (CE) count, amplitude, and duration. The sternocleidomastoid and trapezius muscles contracted about 40-70times per hour in the natural environment. Their EMG activity pattern mainly consisted of short-lasting, low-amplitude CEs. The counts and amplitude of sternocleidomastoid CEs did not differ across vocational and non-vocational conditions. The number and amplitude of trapezius CEs were slightly but significantly higher during the vocational condition. There were highly significant (p<0.001) differences in duration of CEs across conditions, with two to threefold increase in the average duration of trapezius muscle contractions found in the vocational setting. During orthodontic work, operators commonly hold muscular contractions for significantly longer periods than are encountered in non-vocational settings. This behaviour may be associated causally with the increases seen in WMSDs through proposed pathophysiological mechanisms occurring at the motor unit level. Our findings may also be valid for other occupations characterised by seated static postures with precision hand and wrist movements.

  2. Ultrasound imaging of the lateral abdominal wall muscles in individuals with lumbopelvic pain and signs of concurrent hypocapnia.

    PubMed

    Whittaker, Jackie L

    2008-10-01

    The purpose of this study was to compare the change in thickness of transversus abdominis (TrA) and internal oblique (IO) muscles, during resting supine respiration, in individuals with lumbopelvic pain (LP) to those who in addition to LP, demonstrate signs of concurrent hypocapnia (LP&HYPO). B-mode ultrasound images were obtained at the height of inspiration, and at the end of expiration, over three subsequent breaths during a single session. The average percent change in thickness of TrA during resting respiration in the LP&HYPO group (20.8+/-7.6%) was found to be statistically greater (P<0.001) than that of the LP only group (1.3+/-5.8%), while the difference between the groups for the percent change in thickness of IO (LP&HYPO 9.2+/-8.1%, LP 2.0+/-7.2%) did not differ (P=0.073). These findings suggest that respiratory modulation of TrA thickness, as measured by ultrasound imaging, greater than 20%, detected in a resting supine position, may be associated with an episode of hypocapnia, and if present warrants further investigation.

  3. Afferent contribution to locomotor muscle activity during unconstrained overground human walking: an analysis of triceps surae muscle fascicles.

    PubMed

    af Klint, R; Cronin, N J; Ishikawa, M; Sinkjaer, T; Grey, M J

    2010-03-01

    Plantar flexor series elasticity can be used to dissociate muscle-fascicle and muscle-tendon behavior and thus afferent feedback during human walking. We used electromyography (EMG) and high-speed ultrasonography concomitantly to monitor muscle activity and muscle fascicle behavior in 19 healthy volunteers as they walked across a platform. On random trials, the platform was dropped (8 cm, 0.9 g acceleration) or held at a small inclination (up to +/-3 degrees in the parasagittal plane) with respect to level ground. Dropping the platform in the mid and late phases of stance produced a depression in the soleus muscle activity with an onset latency of about 50 ms. The reduction in ground reaction force also unloaded the plantar flexor muscles. The soleus muscle fascicles shortened with a minimum delay of 14 ms. Small variations in platform inclination produced significant changes in triceps surae muscle activity; EMG increased when stepping on an inclined surface and decreased when stepping on a declined surface. This sensory modulation of the locomotor output was concomitant with changes in triceps surae muscle fascicle and gastrocnemius tendon length. Assuming that afferent activity correlates to these mechanical changes, our results indicate that within-step sensory feedback from the plantar flexor muscles automatically adjusts muscle activity to compensate for small ground irregularities. The delayed onset of muscle fascicle movement after dropping the platform indicates that at least the initial part of the soleus depression is more likely mediated by a decrease in force feedback than length-sensitive feedback, indicating that force feedback contributes to the locomotor activity in human walking.

  4. Physical Activity and Reduced Intra-abdominal Fat in Midlife African-American and White Women

    PubMed Central

    Dugan, Sheila A.; Everson-Rose, Susan A.; Karavolos, Kelly; Avery, Elizabeth F.; Wesley, Deidre E.; Powell, Lynda H.

    2011-01-01

    The purpose of our study was to determine whether self-reported physical activity (PA), including recreational, household, and exercise activities, is associated with intra-abdominal fat (IAF) in community-dwelling white and black midlife women. We performed a cross-sectional study of 369 women from the Chicago site of the Study of Women’s Health Across the Nation (SWAN) ancillary study, the SWAN Fat Patterning Study. PA level was the independent variable, and IAF, assessed by computerized tomography (CT) scan, was the dependent variable. Measures were obtained at SWAN Fat Patterning Baseline visit between August 2002 and December 2005. Linear regression models explored the association between PA and IAF. The first model included IAF as the outcome and total score PA as the main predictor, adjusting for total percent fat mass, age, and ethnicity. The second model included education, parity, sex hormone–binding globulin (SHBG) level, and depressive symptoms, measured by Center for Epidemiological Studies-Depression (CES-D) scale. Each 1-point higher total PA score was associated with a 4.0 cm2 lower amount of IAF (P = 0.004), independent of total percent fat mass, age, ethnicity, SHBG level, educational level, CES-D, and parity. Associations did not differ between white and black women. This study demonstrates a significant negative association between PA and IAF independent of multiple covariates in midlife women. Our findings suggest that motivating white and black women to increase PA during midlife may lessen IAF, which may have a positive impact on subsequent development of diabetes and cardiovascular disease. PMID:19876007

  5. Kettlebell swing, snatch, and bottoms-up carry: back and hip muscle activation, motion, and low back loads.

    PubMed

    McGill, Stuart M; Marshall, Leigh W

    2012-01-01

    The intent of this study was to quantify spine loading during different kettlebell swings and carries. No previously published studies of tissue loads during kettlebell exercises could be found. Given the popularity of kettlebells, this study was designed to provide an insight into the resulting joint loads. Seven male subjects participated in this investigation. In addition, a single case study of the kettlebell swing was performed on an accomplished kettlebell master. Electromyography, ground reaction forces (GRFs), and 3D kinematic data were recorded during exercises using a 16-kg kettlebell. These variables were input into an anatomically detailed biomechanical model that used normalized muscle activation; GRF; and spine, hip, and knee motion to calculate spine compression and shear loads. It was found that kettlebell swings create a hip-hinge squat pattern characterized by rapid muscle activation-relaxation cycles of substantial magnitudes (∼50% of a maximal voluntary contraction [MVC] for the low back extensors and 80% MVC for the gluteal muscles with a 16-kg kettlebell) resulting in about 3,200 N of low back compression. Abdominal muscular pulses together with the muscle bracing associated with carries create kettlebell-specific training opportunities. Some unique loading patterns discovered during the kettlebell swing included the posterior shear of the L4 vertebra on L5, which is opposite in polarity to a traditional lift. Thus, quantitative analysis provides an insight into why many individuals credit kettlebell swings with restoring and enhancing back health and function, although a few find that they irritate tissues.

  6. Variation in masticatory muscle activity during subsequent, submaximal clenching efforts.

    PubMed

    Lobbezoo, F; Huddleston Slater, J J R

    2002-06-01

    In previous studies to the relative contribution of the jaw closing muscles to the maintenance of submaximal clenching levels, a considerable variation in the electromyography (EMG) activities of these muscles during subsequent efforts was found. In this study, it was examined to what extent this variation could be explained by coincidental variations in mandibular positioning. From seven healthy individuals, a total of 90 EMG sweeps was recorded: three conditions (intercuspal position and two types of stabilization appliances) x three clenching levels (10, 30 and 50% of maximum voluntary contraction level) x 10 repetitions. Mandibular position was monitored with a six degrees of freedom opto-electronic jaw movement recording system. Variations in mandibular positioning during subsequent, submaximal clenching efforts explained up to 25% of the variance in the indices that quantify the relative contribution of the jaw closing muscles to the total clenching effort (P=0.000; ANOVA). Only a weak dependency of positioning upon clenching condition was found whereas during higher clenching levels, the positioning effect tended to be smaller than during lower levels. In conclusion small, coincidental variations in mandibular positioning during subsequent clenching efforts partly explain the variance in EMG activity of jaw closing muscles, especially at lower clenching levels.

  7. The effects of finger extension on shoulder muscle activity

    PubMed Central

    Yi, Chae-Woo; Shin, Ju-Yong; Kim, Youn-Joung

    2015-01-01

    [Purpose] This study aims to examine the effects of the extension of the fingers (distal upper limb) on the activity of the shoulder muscles (proximal upper limb). [Subjects and Methods] This study involved 14 healthy male adults with no musculoskeletal disorder or pain related to the shoulders and hands. The subjects in a sitting posture abducted the angle of the shoulder joints at 60° and had their palms in the front direction. Electromyography (EMG) was comparatively analyzed to look at the activities of the infraspinatus (IS) and rhomboid major (RM) when the fingers were extended and relaxed. [Results] The activity of the IS was statistically significantly higher when the fingers were extended than when they were relaxed. [Conclusion] According to the result of this study, finger extension is considered to affect the muscles for connected shoulder joint stability. PMID:26504277

  8. Satellite cell activity in muscle regeneration after contusion in rats.

    PubMed

    Srikuea, Ratchakrit; Pholpramool, Chumpol; Kitiyanant, Yindee; Yimlamai, Tossaporn

    2010-11-01

    1. The role of satellite cells in muscle growth during development is well documented, but the involvement of these cells in muscle repair after contusion is less well known. In the present study, we investigated the time-course of satellite cell activity (from 3h to 7days) after contusion of rat gastrocnemius muscle using specific molecular markers for immunofluorescence and real-time polymerase chain reaction (PCR). 2. Inflammation of the injured muscle occurred within 6h, followed by disintegration of the damaged myofibres within 12h. Newly formed myofibres appeared by Day 7. 3. The number of MyoD-positive nuclei (activated satellite cells) in the injured muscle was significantly increased by 6h, reaching a maximum by 12h after contusion. However, the number of MyoD-positive nuclei decreased towards control levels by Day 7. Changes in the number of bromodeoxyuridine-labelled nuclei (proliferating satellite cells) paralleled the changes seen in the number of MyoD-positive nuclei. Conversely, expression of myogenin protein was not apparent until Day 3 and increased further by Day 7. Colabelling of MyoD and myogenin was seen in only a few cells. 4. The time-course of MyoD mRNA expression corresponded with MyoD protein expression. However, there were two peaks in myogenin mRNA expression: 6h and Day 7 after contusion. The second peak coincided with upregulation of myostatin mRNA levels. 5. The results of the present study suggest that contusion activates a homogeneous population of satellite cells to proliferate within 3days, followed by differentiation to form new myofibres. The latter may be regulated, in part, by myostatin.

  9. Systematic review of core muscle activity during physical fitness exercises.

    PubMed

    Martuscello, Jason M; Nuzzo, James L; Ashley, Candi D; Campbell, Bill I; Orriola, John J; Mayer, John M

    2013-06-01

    A consensus has not been reached among strength and conditioning specialists regarding what physical fitness exercises are most effective to stimulate activity of the core muscles. Thus, the purpose of this article was to systematically review the literature on the electromyographic (EMG) activity of 3 core muscles (lumbar multifidus, transverse abdominis, quadratus lumborum) during physical fitness exercises in healthy adults. CINAHL, Cochrane Central Register of Controlled Trials, EMBASE, PubMed, SPORTdiscus, and Web of Science databases were searched for relevant articles using a search strategy designed by the investigators. Seventeen studies enrolling 252 participants met the review's inclusion/exclusion criteria. Physical fitness exercises were partitioned into 5 major types: traditional core, core stability, ball/device, free weight, and noncore free weight. Strength of evidence was assessed and summarized for comparisons among exercise types. The major findings of this review with moderate levels of evidence indicate that lumbar multifidus EMG activity is greater during free weight exercises compared with ball/device exercises and is similar during core stability and ball/device exercises. Transverse abdominis EMG activity is similar during core stability and ball/device exercises. No studies were uncovered for quadratus lumborum EMG activity during physical fitness exercises. The available evidence suggests that strength and conditioning specialists should focus on implementing multijoint free weight exercises, rather than core-specific exercises, to adequately train the core muscles in their athletes and clients.

  10. Trunk muscle activation during golf swing: Baseline and threshold.

    PubMed

    Silva, Luís; Marta, Sérgio; Vaz, João; Fernandes, Orlando; Castro, Maria António; Pezarat-Correia, Pedro

    2013-10-01

    There is a lack of studies regarding EMG temporal analysis during dynamic and complex motor tasks, such as golf swing. The aim of this study is to analyze the EMG onset during the golf swing, by comparing two different threshold methods. Method A threshold was determined using the baseline activity recorded between two maximum voluntary contraction (MVC). Method B threshold was calculated using the mean EMG activity for 1000ms before the 500ms prior to the start of the Backswing. Two different clubs were also studied. Three-way repeated measures ANOVA was used to compare methods, muscles and clubs. Two-way mixed Intraclass Correlation Coefficient (ICC) with absolute agreement was used to determine the methods reliability. Club type usage showed no influence in onset detection. Rectus abdominis (RA) showed the higher agreement between methods. Erector spinae (ES), on the other hand, showed a very low agreement, that might be related to postural activity before the swing. External oblique (EO) is the first being activated, at 1295ms prior impact. There is a similar activation time between right and left muscles sides, although the right EO showed better agreement between methods than left side. Therefore, the algorithms usage is task- and muscle-dependent.

  11. Muscle metabolic function and free-living physical activity.

    PubMed

    Hunter, Gary R; Larson-Meyer, D Enette; Sirikul, Bovorn; Newcomer, Bradley R

    2006-11-01

    We have previously shown that muscle metabolic function measured during exercise is related to exercise performance and subsequent 1-yr weight gain. Because it is well established that physical activity is important in weight maintenance, we examined muscle function relationships with free-living energy expenditure and physical activity. Subjects were 71 premenopausal black and white women. Muscle metabolism was evaluated by (31)P magnetic resonance spectroscopy during 90-s isometric plantar flexion contractions (45% maximum). Free-living energy expenditure (TEE) was measured using doubly labeled water, activity-related energy expenditure (AEE) was calculated as 0.9 x TEE - sleeping energy expenditure from room calorimetry, and free-living physical activity (ARTE) was calculated by dividing AEE by energy cost of standard physical activities. At the end of exercise, anaerobic glycolytic rate (ANGLY) and muscle concentration of phosphomonoesters (PME) were negatively related to TEE, AEE, and ARTE (P < 0.05). Multiple regression analysis showed that both PME (partial r = -0.29, <0.02) and ANGLY (partial r = -0.24, P < 0.04) were independently related to ARTE. PME, primarily glucose-6-phosphate and fructose-6-phosphate, was significantly related to ratings of perceived exertion (r = 0.21, P < or = 0.05) during a maximal treadmill test. PME was not related to ARTE after inclusion of RPE in the multiple regression model, suggesting that PME may be obtaining its relationship with ARTE through an increased perception of effort during physical activity. In conclusion, physically inactive individuals tend to be more dependent on anaerobic glycolysis during exercise while relying on a glycolytic pathway that may not be functioning optimally.

  12. [Abdominal paracentesis].

    PubMed

    Glauser, Frédéric; Barras, Anne-Catherine; Pache, Isabelle; Monti, Matteo

    2008-10-29

    Abdominal paracentesis is frequently performed in the clinical setting. Every newly developed ascites need to be investigated by abdominal paracentesis. Any clinical or biological deterioration in patients with chronic ascites also requires a new paracentesis. Therapeutically abdominal paracentesis is performed for refractory or symptomatic ascites. As other invasive procedures, it is critical to master its indications, contra-indications and complications. The aim of this article is to review the basics of abdominal paracentesis in order to help physicians to carry out this technical skill.

  13. Muscle strain injuries.

    PubMed

    Garrett, W E

    1996-01-01

    One of the most common injuries seen in the office of the practicing physician is the muscle strain. Until recently, little data were available on the basic science and clinical application of this basic science for the treatment and prevention of muscle strains. Studies in the last 10 years represent action taken on the direction of investigation into muscle strain injuries from the laboratory and clinical fronts. Findings from the laboratory indicate that certain muscles are susceptible to strain injury (muscles that cross multiple joints or have complex architecture). These muscles have a strain threshold for both passive and active injury. Strain injury is not the result of muscle contraction alone, rather, strains are the result of excessive stretch or stretch while the muscle is being activated. When the muscle tears, the damage is localized very near the muscle-tendon junction. After injury, the muscle is weaker and at risk for further injury. The force output of the muscle returns over the following days as the muscle undertakes a predictable progression toward tissue healing. Current imaging studies have been used clinically to document the site of injury to the muscle-tendon junction. The commonly injured muscles have been described and include the hamstring, the rectus femoris, gastrocnemius, and adductor longus muscles. Injuries inconsistent with involvement of a single muscle-tendon junction proved to be at tendinous origins rather than within the muscle belly. Important information has also been provided regarding injuries with poor prognosis, which are potentially repairable surgically, including injuries to the rectus femoris muscle, the hamstring origin, and the abdominal wall. Data important to the management of common muscle injuries have been published. The risks of reinjury have been documented. The early efficacy and potential for long-term risks of nonsteroidal antiinflammatory agents have been shown. New data can also be applied to the field

  14. Analysis of muscle activity during active pelvic tilting in sagittal plane

    PubMed Central

    TAKAKI, Sho; KANEOKA, Koji; OKUBO, Yu; OTSUKA, Satoru; TATSUMURA, Masaki; SHIINA, Itsuo; MIYAKAWA, Shumpei

    2016-01-01

    Background: Pelvic tilting is performed to improve lumbopelvic flexibility or retrain the motor control of local muscles. However, few studies investigated the activity of local muscles during pelvic tilting. Purpose: The purpose of this study was to investigate muscle activity during anterior and posterior pelvic tilting. Method: Twelve healthy males (age, 22.6 ± 1.4 years) participated. Fine-wire electrodes were inserted into the bilateral lumbar multifidus (MF) and transversus abdominis (TrA). Surface electrodes were used to record activity of the bilateral rectus abdominis, external oblique, and erector spinae (ES), and the unilateral right latissimus dorsi, gluteus maximus, semitendinosus, and rectus femoris muscles. The electromyographic activities during anterior and posterior pelvic tilting in a standing position were recorded and expressed as a percentage of the maximum voluntary contraction (%MVC) for each muscle. Results: The activities of the bilateral MF (right: 23.9 ± 15.9 %MVC, left: 23.9 ± 15.1 %MVC) and right ES (19.0 ± 13.3 %MVC) were significantly greater than those of the other muscles during anterior pelvic tilting. The activity of the left TrA (14.8 ± 16.4 %MVC) was significantly greater than that of the other muscles during posterior pelvic tilting. Conclusions: The results suggested that the MF and ES are related to anterior pelvic tilting. The activity of the TrA, which was classified as a local muscle, was greater during posterior pelvic tilting. This study indicated that local muscles such as the MF and TrA may be related to pelvic tilting. PMID:28289581

  15. Muscle shortening velocity depends on tissue inertia and level of activation during submaximal contractions.

    PubMed

    Ross, Stephanie A; Wakeling, James M

    2016-06-01

    In order to perform external work, muscles must do additional internal work to deform their tissue, and in particular, to overcome the inertia due to their internal mass. However, the contribution of the internal mass within a muscle to the mechanical output of that muscle has only rarely been studied. Here, we use a dynamic, multi-element Hill-type muscle model to examine the effects of the inertial mass within muscle on its contractile performance. We find that the maximum strain-rate of muscle is slower for lower activations and larger muscle sizes. As muscle size increases, the ability of the muscle to overcome its inertial load will decrease, as muscle tension is proportional to cross-sectional area and inertial load is proportional to mass. Thus, muscles that are larger in size will have a higher inertial cost to contraction. Similarly, when muscle size and inertial load are held constant, decreasing muscle activation will increase inertial cost to contraction by reducing muscle tension. These results show that inertial loads within muscle contribute to a slowing of muscle contractile velocities (strain-rates), particularly at the submaximal activations that are typical during animal locomotion.

  16. Myomaker: A membrane activator of myoblast fusion and muscle formation

    PubMed Central

    Millay, Douglas P.; O’Rourke, Jason R.; Sutherland, Lillian B.; Bezprozvannaya, Svetlana; Shelton, John M.; Bassel-Duby, Rhonda; Olson, Eric N.

    2013-01-01

    Summary Fusion of myoblasts is essential for the formation of multi-nucleated muscle fibers. However, the identity of myogenic proteins that directly govern this fusion process has remained elusive. Here, we discovered a muscle-specific membrane protein, named Myomaker, that controls myoblast fusion. Myomaker is expressed on the cell surface of myoblasts during fusion and is down-regulated thereafter. Over-expression of Myomaker in myoblasts dramatically enhances fusion and genetic disruption of Myomaker in mice causes perinatal death due to an absence of multi-nucleated muscle fibers. Remarkably, forced expression of Myomaker in fibroblasts promotes fusion with myoblasts, demonstrating the direct participation of this protein in the fusion process. Pharmacologic perturbation of the actin cytoskeleton abolishes the activity of Myomaker, consistent with prior studies implicating actin dynamics in myoblast fusion. These findings reveal a long-sought myogenic fusion protein both necessary and sufficient for mammalian myoblast fusion and provide new insights into the molecular underpinnings of muscle formation. PMID:23868259

  17. Adaptation of muscle gene expression to changes in contractile activity

    NASA Technical Reports Server (NTRS)

    Booth, F. W.; Babij, P.; Thomason, D. B.; Wong, T. S.; Morrison, P. R.

    1987-01-01

    A review of the existing literature regarding the effects of different types of physical activities on the gene expression of adult skeletal muscles leads us to conclude that each type of exercise training program has, as a result, a different phenotype, which means that there are multiple mechanisms, each producing a unique phenotype. A portion of the facts which support this position is presented and interpreted here. [Abstract translated from the original French by NASA].

  18. Interplay between body stabilisation and quadriceps muscle activation capacity.

    PubMed

    Bampouras, Theodoros M; Reeves, Neil D; Baltzopoulos, Vasilios; Maganaris, Constantinos N

    2017-03-22

    The study aimed to distinguish the effect of stabilisation and muscle activation on quadriceps maximal isometric voluntary contraction (MVC) torque generation. Nine subjects performed (a) an MVC with restrained leg and pelvis (Typical MVC), (b) a Typical MVC with handgrip (Handgrip MVC), (c) an MVC focusing on contracting the knee extensors only (Isolated knee extension MVC), and (d) an MVC with unrestrained leg and pelvis (Unrestrained MVC). Torque and activation capacity between conditions were compared with repeated measures ANOVA and dependent t-tests. EMG (from eleven remote muscles) was compared using Friedman's and Wilcoxon. Typical MVC (277.2±49.6Nm) and Handgrip MVC (261.0±55.4Nm) were higher than Isolated knee extension MVC (210.2±48.3Nm, p<0.05) and Unrestrained MVC (195.2±49.7Nm, p<0.05) torque. Typical MVC (83.1±15.9%) activation was higher than Isolated knee extension MVC (68.9±24.3%, p<0.05), and both Typical MVC and Handgrip MVC (81.8±17.4%) were higher than Unrestrained MVC (64.9±16.2%, p<0.05). Only flexor carpi radialis, biceps brachii, triceps brachii and external oblique muscles showed EMG differences, with Isolated knee extension MVC consistently lower than Typical MVC or Handgrip MVC. Stabilisation of the involved segments is the prime concern allowing fuller activation of the muscle, reinforcing the need for close attention to stabilisation during dynamometry-based knee joint functional assessment.

  19. The muscle activity of trout exposed to unsteady flow.

    PubMed

    Klein, Adrian; Bleckmann, Horst

    2017-02-23

    In running water trout seek out special regions for station holding. Trout exposed to flow fluctuations caused by a cylinder hold station immediately upstream of the cylinder (bow wake region), adjacent to the cylinder (entraining region) or downstream of the cylinder (Kármán gait). In addition it was shown that the activity of the axial red swimming muscles is reduced during Kármán gaiting. Up to now only the two-dimensional (horizontal) extensions of the above regions have been examined. We determined both, the horizontal and vertical extension of the Kármán gait, entraining and bow wake region by continuously recording the position (spatial resolution 1 cm(3)) of trout for 3 h. In addition we continuously recorded the trunk muscle activity. The Kármán gate region had the smallest vertical extension (13 cm, water level 28-29 cm, length of the submerged cylinder 27 cm), followed by the entraining (21 cm) and bow wake region (25 cm). A fourth so far unknown region used for station holding was immediately below a stationary surface wave which, at flow velocities ≥36 cm s(- 1), developed slightly downstream of the cylinder. While in any of the above regions the activity of the axial swimming muscles was significantly reduced.

  20. Fatigue-related firing of distal muscle nociceptors reduces voluntary activation of proximal muscles of the same limb.

    PubMed

    Kennedy, David S; McNeil, Chris J; Gandevia, Simon C; Taylor, Janet L

    2014-02-15

    With fatiguing exercise, firing of group III/IV muscle afferents reduces voluntary activation and force of the exercised muscles. These afferents can also act across agonist/antagonist pairs, reducing voluntary activation and force in nonfatigued muscles. We hypothesized that maintained firing of group III/IV muscle afferents after a fatiguing adductor pollicis (AP) contraction would decrease voluntary activation and force of AP and ipsilateral elbow flexors. In two experiments (n = 10) we examined voluntary activation of AP and elbow flexors by measuring changes in superimposed twitches evoked by ulnar nerve stimulation and transcranial magnetic stimulation of the motor cortex, respectively. Inflation of a sphygmomanometer cuff after a 2-min AP maximal voluntary contraction (MVC) blocked circulation of the hand for 2 min and maintained firing of group III/IV muscle afferents. After a 2-min AP MVC, maximal AP voluntary activation was lower with than without ischemia (56.2 ± 17.7% vs. 76.3 ± 14.6%; mean ± SD; P < 0.05) as was force (40.3 ± 12.8% vs. 57.1 ± 13.8% peak MVC; P < 0.05). Likewise, after a 2-min AP MVC, elbow flexion voluntary activation was lower with than without ischemia (88.3 ± 7.5% vs. 93.6 ± 3.9%; P < 0.05) as was torque (80.2 ± 4.6% vs. 86.6 ± 1.0% peak MVC; P < 0.05). Pain during ischemia was reported as Moderate to Very Strong. Postfatigue firing of group III/IV muscle afferents from the hand decreased voluntary drive and force of AP. Moreover, this effect decreased voluntary drive and torque of proximal unfatigued muscles, the elbow flexors. Fatigue-sensitive group III/IV muscle nociceptors act to limit voluntary drive not only to fatigued muscles but also to unfatigued muscles within the same limb.

  1. Distinct muscle apoptotic pathways are activated in muscles with different fiber types a rat model of critical illness myopathy

    PubMed Central

    Barnes, Benjamin T.; Confides, Amy L.; Rich, Mark M.; Dupont-Versteegden, Esther E.

    2015-01-01

    Critical illness myopathy (CIM) is associated with severe muscle atrophy and fatigue in affected patients. Apoptotic signaling is involved in atrophy and is elevated in muscles from patients with CIM. In this study we investigated underlying mechanisms of apoptosis-related pathways in muscles with different fiber type composition in a rat model of CIM using denervation and glucocorticoid administration (denervation and steroid-induced myopathy, DSIM). Soleus and tibialis anterior (TA) muscles showed severe muscle atrophy (40–60% of control muscle weight) and significant apoptosis in interstitial as well as myofiber nuclei that was similar between the two muscles with DSIM. Caspase-3 and −8 activities, but not caspase-9 and −12, were elevated in TA and not in soleus muscle, while the caspase-independent proteins endonuclease G (EndoG) and apoptosis inducing factor (AIF) were not changed in abundance nor differentially localized in either muscle. Anti-apoptotic proteins HSP70, −27, and apoptosis repressor with a caspase recruitment domain (ARC) were elevated in soleus compared to TA muscle and ARC was significantly decreased with induction of DSIM in soleus. Results indicate that apoptosis is a significant process associated with DSIM in both soleus and TA muscles, and that apoptosis-associated processes are differentially regulated in muscles of different function and fiber type undergoing atrophy due to DSIM. We conclude that interventions combating apoptosis with CIM may need to be directed towards inhibiting caspase-dependent as well as -independent mechanisms to be able to affect muscles of all fiber types. PMID:25740800

  2. Distinct muscle apoptotic pathways are activated in muscles with different fiber types in a rat model of critical illness myopathy.

    PubMed

    Barnes, Benjamin T; Confides, Amy L; Rich, Mark M; Dupont-Versteegden, Esther E

    2015-06-01

    Critical illness myopathy (CIM) is associated with severe muscle atrophy and fatigue in affected patients. Apoptotic signaling is involved in atrophy and is elevated in muscles from patients with CIM. In this study we investigated underlying mechanisms of apoptosis-related pathways in muscles with different fiber type composition in a rat model of CIM using denervation and glucocorticoid administration (denervation and steroid-induced myopathy, DSIM). Soleus and tibialis anterior (TA) muscles showed severe muscle atrophy (40-60% of control muscle weight) and significant apoptosis in interstitial as well as myofiber nuclei that was similar between the two muscles with DSIM. Caspase-3 and -8 activities, but not caspase-9 and -12, were elevated in TA and not in soleus muscle, while the caspase-independent proteins endonuclease G (EndoG) and apoptosis inducing factor (AIF) were not changed in abundance nor differentially localized in either muscle. Anti-apoptotic proteins HSP70, -27, and apoptosis repressor with a caspase recruitment domain (ARC) were elevated in soleus compared to TA muscle and ARC was significantly decreased with induction of DSIM in soleus. Results indicate that apoptosis is a significant process associated with DSIM in both soleus and TA muscles, and that apoptosis-associated processes are differentially regulated in muscles of different function and fiber type undergoing atrophy due to DSIM. We conclude that interventions combating apoptosis with CIM may need to be directed towards inhibiting caspase-dependent as well as -independent mechanisms to be able to affect muscles of all fiber types.

  3. The assessment methods of laryngeal muscle activity in muscle tension dysphonia: a review.

    PubMed

    Khoddami, Seyyedeh Maryam; Nakhostin Ansari, Noureddin; Izadi, Farzad; Talebian Moghadam, Saeed

    2013-11-04

    The purpose of this paper is to review the methods used for the assessment of muscular tension dysphonia (MTD). The MTD is a functional voice disorder associated with abnormal laryngeal muscle activity. Various assessment methods are available in the literature to evaluate the laryngeal hyperfunction. The case history, laryngoscopy, and palpation are clinical methods for the assessment of patients with MTD. Radiography and surface electromyography (EMG) are objective methods to provide physiological information about MTD. Recent studies show that surface EMG can be an effective tool for assessing muscular tension in MTD.

  4. A Role for Nitric Oxide in Muscle Repair: Nitric Oxide–mediated Activation of Muscle Satellite Cells

    PubMed Central

    Anderson, Judy E.

    2000-01-01

    Muscle satellite cells are quiescent precursors interposed between myofibers and a sheath of external lamina. Although their activation and recruitment to cycle enable muscle repair and adaptation, the activation signal is not known. Evidence is presented that nitric oxide (NO) mediates satellite cell activation, including morphological hypertrophy and decreased adhesion in the fiber-lamina complex. Activation in vivo occurred within 1 min after injury. Cell isolation and histology showed that pharmacological inhibition of nitric oxide synthase (NOS) activity prevented the immediate injury-induced myogenic cell release and delayed the hypertrophy of satellite cells in that muscle. Transient activation of satellite cells in contralateral muscles 10 min later suggested that a circulating factor may interact with NO-mediated signaling. Interestingly, satellite cell activation in muscles of mdx dystrophic mice and NOS-I knockout mice quantitatively resembled NOS-inhibited release of normal cells, in agreement with reports of displaced and reduced NOS expression in dystrophin-deficient mdx muscle and the complete loss of NOS-I expression in knockout mice. Brief NOS inhibition in normal and mdx mice during injury produced subtle alterations in subsequent repair, including apoptosis in myotube nuclei and myotube formation inside laminar sheaths. Longer NOS inhibition delayed and restricted the extent of repair and resulted in fiber branching. A model proposes the hypothesis that NO release mediates satellite cell activation, possibly via shear-induced rapid increases in NOS activity that produce “NO transients.” PMID:10793157

  5. Fast skeletal muscle troponin activation increases force of mouse fast skeletal muscle and ameliorates weakness due to nebulin-deficiency.

    PubMed

    Lee, Eun-Jeong; De Winter, Josine M; Buck, Danielle; Jasper, Jeffrey R; Malik, Fady I; Labeit, Siegfried; Ottenheijm, Coen A; Granzier, Henk

    2013-01-01

    The effect of the fast skeletal muscle troponin activator, CK-2066260, on calcium-induced force development was studied in skinned fast skeletal muscle fibers from wildtype (WT) and nebulin deficient (NEB KO) mice. Nebulin is a sarcomeric protein that when absent (NEB KO mouse) or present at low levels (nemaline myopathy (NM) patients with NEB mutations) causes muscle weakness. We studied the effect of fast skeletal troponin activation on WT muscle and tested whether it might be a therapeutic mechanism to increase muscle strength in nebulin deficient muscle. We measured tension-pCa relations with and without added CK-2066260. Maximal active tension in NEB KO tibialis cranialis fibers in the absence of CK-2066260 was ∼60% less than in WT fibers, consistent with earlier work. CK-2066260 shifted the tension-calcium relationship leftwards, with the largest relative increase (up to 8-fold) at low to intermediate calcium levels. This was a general effect that was present in both WT and NEB KO fiber bundles. At pCa levels above ∼6.0 (i.e., calcium concentrations <1 µM), CK-2066260 increased tension of NEB KO fibers to beyond that of WT fibers. Crossbridge cycling kinetics were studied by measuring k(tr) (rate constant of force redevelopment following a rapid shortening/restretch). CK-2066260 greatly increased k(tr) at submaximal activation levels in both WT and NEB KO fiber bundles. We also studied the sarcomere length (SL) dependence of the CK-2066260 effect (SL 2.1 µm and 2.6 µm) and found that in the NEB KO fibers, CK-2066260 had a larger effect on calcium sensitivity at the long SL. We conclude that fast skeletal muscle troponin activation increases force at submaximal activation in both wildtype and NEB KO fiber bundles and, importantly, that this troponin activation is a potential therapeutic mechanism for increasing force in NM and other skeletal muscle diseases with loss of muscle strength.

  6. An active learning mammalian skeletal muscle lab demonstrating contractile and kinetic properties of fast- and slow-twitch muscle.

    PubMed

    Head, S I; Arber, M B

    2013-12-01

    The fact that humans possess fast- and slow-twitch muscle in the ratio of ∼50% has profound implications for designing exercise training strategies for power and endurance activities. With the growth of exercise and sport science courses, we have seen the need to develop an undergraduate student laboratory that demonstrates the basic properties of fast- and slow-twitch mammalian skeletal muscle. This laboratory illustrates the major differences in contractile properties and fatigue profiles exhibited by the two muscle types. Students compare and contrast twitch kinetics, fused tetanus characteristics, force-frequency relationships, and fatigue properties of fast- and slow-twitch muscles. Examples of results collected by students during class are used to illustrate the type of data collected and analysis performed. During the laboratory, students are encouraged to connect factual information from their skeletal muscle lectures to their laboratory findings. This enables student learning in an active fashion; in particular, the isolated muscle preparation demonstrates that much of what makes muscle fast or slow is myogenic and not the product of the nervous or circulatory systems. This has far-reaching implications for motor control and exercise behavior and therefore is a crucial element in exercise science, with its focus on power and endurance sport activities. To measure student satisfaction with this active learning technique, a questionnaire was administered after the laboratory; 96% of the comments were positive in their support of active versus passive learning strategies.

  7. Abdominal obesity, insulin resistance, and the metabolic syndrome: contribution of physical activity/exercise.

    PubMed

    Ross, Robert; Després, Jean-Pierre

    2009-12-01

    The metabolic syndrome, a constellation of metabolic abnormalities, which include abdominal obesity, insulin resistance, an atherogenic dyslipidemia, elevated blood pressure, a prothrombotic profile, and inflammation is associated with an increased risk of type 2 diabetes (1), cardiovascular disease (2), and mortality (3). The prevalence of individuals with these clustering abnormalities has been steadily increasing over the past two decades, is now estimated to affect at least a quarter of the US population, and is particularly prevalent among older adults (4). Similarly, abdominal obesity, as crudely estimated by an elevated waist circumference, is the most prevalent manifestation of the metabolic syndrome and affects 36% of men and 52% of women, according to the 1999-2000 US National Health and Nutrition Examination Study (5).

  8. Model identification of stomatognathic muscle system activity during mastication

    PubMed Central

    Kijak, Edward; Margielewicz, Jerzy; Lietz-Kijak, Danuta; Wilemska-Kucharzewska, Katarzyna; Kucharzewski, Marek; Śliwiński, Zbigniew

    2017-01-01

    The present study aimed to determine the numeric projection of the function of the mandible and muscle system during mastication. An experimental study was conducted on a healthy 47 year-old subject. On clinical examination no functional disorders were observed. To evaluate the activity of mastication during muscle functioning, bread cubes and hazelnuts were selected (2 cm2 and 1.2/1.3 cm in diameter, respectively) for condyloid processing. An assessment of the activity of mastication during muscle functioning was determined on the basis of numeric calculations conducted with a novel software programme, Kinematics 3D, designed specifically for this study. The efficacy of the model was verified by ensuring the experimentally recorded trajectories were concordant with those calculated numerically. Experimental measurements of the characteristic points of the mandible trajectory were recorded six times. Using the configuration coordinates that were calculated, the dominant componential harmonics of the amplitude-frequency spectrum were identified. The average value of the dominant frequency during mastication of the bread cubes was ~1.16±0.06 Hz, whereas in the case of the hazelnut, this value was nearly two-fold higher at 1.84±0.07 Hz. The most asymmetrical action during mastication was demonstrated to be carried out by the lateral pterygoid muscles, provided that their functioning was not influenced by food consistency. The consistency of the food products had a decisive impact on the frequency of mastication and the number of cycles necessary to grind the food. Model tests on the function of the masticatory organ serve as effective tools since they provide qualitative and quantitative novel information on the functioning of the human masticatory organ. PMID:28123482

  9. Model identification of stomatognathic muscle system activity during mastication.

    PubMed

    Kijak, Edward; Margielewicz, Jerzy; Lietz-Kijak, Danuta; Wilemska-Kucharzewska, Katarzyna; Kucharzewski, Marek; Śliwiński, Zbigniew

    2017-01-01

    The present study aimed to determine the numeric projection of the function of the mandible and muscle system during mastication. An experimental study was conducted on a healthy 47 year-old subject. On clinical examination no functional disorders were observed. To evaluate the activity of mastication during muscle functioning, bread cubes and hazelnuts were selected (2 cm(2) and 1.2/1.3 cm in diameter, respectively) for condyloid processing. An assessment of the activity of mastication during muscle functioning was determined on the basis of numeric calculations conducted with a novel software programme, Kinematics 3D, designed specifically for this study. The efficacy of the model was verified by ensuring the experimentally recorded trajectories were concordant with those calculated numerically. Experimental measurements of the characteristic points of the mandible trajectory were recorded six times. Using the configuration coordinates that were calculated, the dominant componential harmonics of the amplitude-frequency spectrum were identified. The average value of the dominant frequency during mastication of the bread cubes was ~1.16±0.06 Hz, whereas in the case of the hazelnut, this value was nearly two-fold higher at 1.84±0.07 Hz. The most asymmetrical action during mastication was demonstrated to be carried out by the lateral pterygoid muscles, provided that their functioning was not influenced by food consistency. The consistency of the food products had a decisive impact on the frequency of mastication and the number of cycles necessary to grind the food. Model tests on the function of the masticatory organ serve as effective tools since they provide qualitative and quantitative novel information on the functioning of the human masticatory organ.

  10. Core Muscle Activity during TRX Suspension Exercises with and without Kinesiology Taping in Adults with Chronic Low Back Pain: Implications for Rehabilitation

    PubMed Central

    Fong, Shirley S. M.; Tam, Y. T.; Macfarlane, Duncan J.; Ng, Shamay S. M.; Bae, Young-Hyeon; Chan, Eleanor W. Y.; Guo, X.

    2015-01-01

    This study aimed to examine the effects of kinesiology taping (KT) and different TRX suspension workouts on the amplitude of electromyographic (EMG) activity in the core muscles among people with chronic low back pain (LBP). Each participant (total n = 21) was exposed to two KT conditions: no taping and taping, while performing four TRX suspension exercises: (1) hamstring curl, (2) hip abduction in plank, (3) chest press, and (4) 45-degree row. Right transversus abdominis/internal oblique (TrAIO), rectus abdominis (RA), external oblique (EO), and superficial lumbar multifidus (LMF) activity was recorded with surface EMG and expressed as a percentage of the EMG amplitude recorded during a maximal voluntary isometric contraction of the respective muscles. Hip abduction in plank increased TrAIO, RA, and LMF EMG amplitude compared with other TRX positions (P < 0.008). Only the hamstring curl was effective in inducing a high EMG amplitude of LMF (P < 0.001). No significant difference in EMG magnitude was found between the taping and no taping conditions overall (P > 0.05). Hip abduction in plank most effectively activated abdominal muscles, whereas the hamstring curl most effectively activated the paraspinal muscles. Applying KT conferred no immediate benefits in improving the core muscle activation during TRX training in adults with chronic LBP. PMID:26185520

  11. Craniofacial pain and jaw-muscle activity during sleep.

    PubMed

    Yachida, W; Castrillon, E E; Baad-Hansen, L; Jensen, R; Arima, T; Tomonaga, A; Ohata, N; Svensson, P

    2012-06-01

    This study compared the jaw-muscle electromyographic (EMG) activity during sleep in patients with craniofacial pain (n = 63) or no painful conditions (n = 52) and between patients with tension-type headache (TTH: n = 30) and healthy control individuals (n = 30). All participants used a portable single-channel EMG device (Medotech A/S) for four nights. There was no significant difference in EMG activity between craniofacial pain (24.5 ± 17.9 events/hr) and no painful conditions (19.7 ± 14.5), or between TTH (20.8 ± 15.0) and healthy control individuals (15.2 ± 11.6, p >.050). There were positive correlations between EMG activity and number of painful muscles (r = 0.188; p = 0.044), characteristic pain intensity (r = 0.187; p = 0.046), McGill Pain Questionnaire (r = 0.251; p = 0.008), and depression scores (r = 0.291; p = 0.002). Patients with painful conditions had significantly higher night-to-night variability compared with pain-free individuals (p < 0.050). This short-term observational study suggests that there are no major differences between patients with different craniofacial pain conditions and pain-free individuals in terms of jaw-muscle EMG activity recorded with a single-channel EMG device during sleep. However, some associations may exist between the level of EMG activity and various parameters of craniofacial pain. Longitudinal studies are warranted to further explore the relationship between sleep bruxism and craniofacial pain.

  12. Muscle-Strengthening Activities and Participation among Adults in the United States

    ERIC Educational Resources Information Center

    Loustalot, Fleetwood; Carlson, Susan A.; Kruger, Judy; Buchner, David M.; Fulton, Janet E.

    2013-01-01

    Purpose: To describe those who reported meeting the "2008 Physical Activity Guidelines for Americans" ("2008 Guidelines") muscle-strengthening standard of 2 or more days per week, including all seven muscle groups, and to assess the type and location of muscle-strengthening activities performed. Method: Data from HealthStyles…

  13. On the Origin of Muscle Synergies: Invariant Balance in the Co-activation of Agonist and Antagonist Muscle Pairs

    PubMed Central

    Hirai, Hiroaki; Miyazaki, Fumio; Naritomi, Hiroaki; Koba, Keitaro; Oku, Takanori; Uno, Kanna; Uemura, Mitsunori; Nishi, Tomoki; Kageyama, Masayuki; Krebs, Hermano Igo

    2015-01-01

    Investigation of neural representation of movement planning has attracted the attention of neuroscientists, as it may reveal the sensorimotor transformation essential to motor control. The analysis of muscle synergies based on the activity of agonist–antagonist (AA) muscle pairs may provide insight into such transformations, especially for a reference frame in the muscle space. In this study, we examined the AA concept using the following explanatory variables: the AA ratio, which is related to the equilibrium-joint angle, and the AA sum, which is associated with joint stiffness. We formulated muscle synergies as a function of AA sums, positing that muscle synergies are composite units of mechanical impedance. The AA concept can be regarded as another form of the equilibrium-point (EP) hypothesis, and it can be extended to the concept of EP-based synergies. We introduce, here, a novel tool for analyzing the neurological and motor functions underlying human movements and review some initial insights from our results about the relationships between muscle synergies, endpoint stiffness, and virtual trajectories (time series of EP). Our results suggest that (1) muscle synergies reflect an invariant balance in the co-activation of AA muscle pairs; (2) each synergy represents the basis for the radial, tangential, and null movements of the virtual trajectory in the polar coordinates centered on the specific joint at the base of the body; and (3) the alteration of muscle synergies (for example, due to spasticity or rigidity following neurological injury) results in significant distortion of endpoint stiffness and concomitant virtual trajectories. These results indicate that muscle synergies (i.e., the balance of muscle mechanical impedance) are essential for motor control. PMID:26636079

  14. On the Origin of Muscle Synergies: Invariant Balance in the Co-activation of Agonist and Antagonist Muscle Pairs.

    PubMed

    Hirai, Hiroaki; Miyazaki, Fumio; Naritomi, Hiroaki; Koba, Keitaro; Oku, Takanori; Uno, Kanna; Uemura, Mitsunori; Nishi, Tomoki; Kageyama, Masayuki; Krebs, Hermano Igo

    2015-01-01

    Investigation of neural representation of movement planning has attracted the attention of neuroscientists, as it may reveal the sensorimotor transformation essential to motor control. The analysis of muscle synergies based on the activity of agonist-antagonist (AA) muscle pairs may provide insight into such transformations, especially for a reference frame in the muscle space. In this study, we examined the AA concept using the following explanatory variables: the AA ratio, which is related to the equilibrium-joint angle, and the AA sum, which is associated with joint stiffness. We formulated muscle synergies as a function of AA sums, positing that muscle synergies are composite units of mechanical impedance. The AA concept can be regarded as another form of the equilibrium-point (EP) hypothesis, and it can be extended to the concept of EP-based synergies. We introduce, here, a novel tool for analyzing the neurological and motor functions underlying human movements and review some initial insights from our results about the relationships between muscle synergies, endpoint stiffness, and virtual trajectories (time series of EP). Our results suggest that (1) muscle synergies reflect an invariant balance in the co-activation of AA muscle pairs; (2) each synergy represents the basis for the radial, tangential, and null movements of the virtual trajectory in the polar coordinates centered on the specific joint at the base of the body; and (3) the alteration of muscle synergies (for example, due to spasticity or rigidity following neurological injury) results in significant distortion of endpoint stiffness and concomitant virtual trajectories. These results indicate that muscle synergies (i.e., the balance of muscle mechanical impedance) are essential for motor control.

  15. Inward spread of activation in vertebrate muscle fibres

    PubMed Central

    González-Serratos, H.

    1971-01-01

    1. A method for detecting the activation of individual myofibrils or groups of myofibrils within an isolated muscle fibre is described. It consists in making all the myofibrils wavy by setting the fibre in gelatine and compressing it longitudinally; active shortening of myofibrils can then be recognized by the straightening out of the waves. 2. The time course of this straightening during a twitch was found by high-speed ciné micrography. 3. There is a delay of activation between the superficial and central myofibrils, from which the velocity of inward spread of activation can be found. 4. This velocity has a Q10 of 2, and is about 7 cm/sec at 20° C. The mechanism of the inward spread of activation is discussed. 5. On relaxation the waves reappear, showing that there is a spontaneous elongation of the myofibrils. ImagesPlate 1Plate 2Plate 3Plate 4 PMID:5557071

  16. Mechanical Strain Induced Expression of Matrix Metalloproteinase-9 via Stretch-Activated Channels in Rat Abdominal Aortic Dissection

    PubMed Central

    Qiu, ZhiHuang; Chen, LiangWan; Cao, Hua; Chen, Qiang; Peng, Hua

    2017-01-01

    Background The aim of the study was to investigate the expression of matrix metalloproteinase-9 (MMP-9) in rat abdominal aortic dissection (AD) induced by mechanical strain, so as to offer a better understanding of the possible mechanisms of AD. Material/Methods Experimental AD in rats was achieved by the injection of porcine pancreatic elastase. At days 0, 1, 3, 5, 7, 14, 21, and 30 after the establishment of AD model, serum MMP-9 levels were measured by enzyme-linked immunosorbent assay (ELISA). Four groups of vascular rings were stretched in vitro with a mechanical strength of 0 g, 1 g, 3 g, or 5 g for 30 min. Another four groups were pretreated with GdCl3, streptomycin, SN50, and SN50M, followed by stretching with 3 g for 30 min. The messenger RNA and the protein of MMP-9 were analyzed by real-time RT-PCR and Western blotting, and NF-κB p65 was detected by ELISA. Results After the establishment of rat abdominal AD model, the serum MMP-9 levels of AD groups increased significantly. The results showed increased expression of MMP-9 in rat AD vessels stretched with mechanical strength of 1 g, 3 g, and 5 g, but this effect was mostly blocked by Gd Cl3 and streptomycin. The NF-κB activity in aortic rings was activated by stretching with a mechanical strength of 3 g and was blocked by SN50, but not by SN50M. Conclusions The expression of MMP-9 in serum was increased significantly after rat abdominal AD formation. Mechanical strain induced MMP-9 expression in AD vessels, which was mediated through the activation of the stretch-activated channel-induced NF-κB pathway. PMID:28286334

  17. Cerebellar brain inhibition in the target and surround muscles during voluntary tonic activation.

    PubMed

    Panyakaew, Pattamon; Cho, Hyun Joo; Srivanitchapoom, Prachaya; Popa, Traian; Wu, Tianxia; Hallett, Mark

    2016-04-01

    Motor surround inhibition is the neural mechanism that selectively favours the contraction of target muscles and inhibits nearby muscles to prevent unwanted movements. This inhibition was previously reported at the onset of a movement, but not during a tonic contraction. Cerebellar brain inhibition (CBI) is reduced in active muscles during tonic activation; however, it has not been studied in the surround muscles. CBI was evaluated in the first dorsal interosseus (FDI) muscle as the target muscle, and the abductor digiti minimi, flexor carpi radialis and extensor carpi radialis muscles as surround muscles, during rest and tonic activation of the FDI muscle in 21 subjects. Cerebellar stimulation was performed under magnetic resonance imaging-guided neuronavigation targeting lobule VIII of the cerebellar hemisphere. Stimulus intensities for cerebellar stimulation were based on the resting motor cortex threshold (RMT) and adjusted for the depth difference between the cerebellar and motor cortices. We used 90-120% of the adjusted RMT as the conditioning stimulus intensity during rest. The intensity that generated the best CBI at rest in the FDI muscle was selected for use during tonic activation. During selective tonic activation of the FDI muscle, CBI was significantly reduced only for the FDI muscle, and not for the surround muscles. Unconditioned motor evoked potential sizes were increased in all muscles during FDI muscle tonic activation as compared with rest, despite background electromyography activity increasing only for the FDI muscle. Our study suggests that the cerebellum may play an important role in selective tonic finger movement by reducing its inhibition in the motor cortex only for the relevant agonist muscle.

  18. Enzymatic activities in limb muscles subjected to external fixation with ring-hybrid frames.

    PubMed

    Reznick, Abraham Z; Coleman, Raymond; Stein, Haim

    2007-04-01

    Enzymatic activities, which originate in the muscle envelope of tibiae with an experimental segmental bone loss, provide additional evidence for the intimate bone-muscle interrelationships in new bone formation.

  19. Gluteus medius and scapula muscle activations in youth baseball pitchers.

    PubMed

    Oliver, Gretchen D; Weimar, Wendi H; Plummer, Hillary A

    2015-06-01

    The baseball pitching motion is a total kinetic chain activity that must efficiently use both the upper and lower extremity. Of particular importance is the scapular motion, which is critical for humeral positioning and proper alignment of shoulder musculature. It was hypothesized that scapular stability is enhanced by pelvic girdle stability. Therefore, it was the purpose of this study to determine the muscle activations of selected pelvic and scapular stabilizing muscles during a fastball pitch in youth baseball pitchers. Twenty youth baseball pitchers (age: 11.3 + 1.0 years; height: 152.4 + 9.0 cm; weight: 47.5 + 11.3 kg) were recorded throwing 4-seam fastballs for strikes. Data revealed moderate (20-39% maximum voluntary isometric contraction [MVIC]) to moderately strong (>40% MVIC) activation of the ipsilateral (throwing arm side) gluteus medius, upper trapezius, and serratus anterior throughout phases 2 (maximum shoulder external rotation to ball release) and 3 (ball release to maximum shoulder internal rotation). Moderately strong activation (>40% MVIC) of the upper trapezius and serratus anterior was noted during phases 2 and 3 of the pitching motion. Pearson's product-moment correlation revealed significant relationships between bilateral gluteus medius and the force couples about the scapula during all 3 phases of the pitching motion. The results of this study provide important data that improve the understanding of the muscular relationship between the pelvic and scapular stabilizers during the fastball pitch. Training and rehabilitation programs should consider focusing on lumbopelvic-hip and scapular muscle strengthening as well as coordinated strengthening of the pelvic and scapular stabilizers, in baseball pitchers.

  20. Lumbar spinal loads and muscle activity during a golf swing.

    PubMed

    Lim, Young-Tae; Chow, John W; Chae, Woen-Sik

    2012-06-01

    This study estimated the lumbar spinal loads at the L4-L5 level and evaluated electromyographic (EMG) activity of right and left rectus abdominis, external and internal obliques, erector spinae, and latissimus dorsi muscles during a golf swing. Four super VHS camcorders and two force plates were used to obtain three-dimensional (3D) kinematics and kinetics of golf swings performed by five male collegiate golfers. Average EMG levels for different phases of golf swing were determined. An EMG-assisted optimization model was applied to compute the contact forces acting on the L4-L5. The results revealed a mean peak compressive load of over six times the body weight (BW) during the downswing and mean peak anterior and medial shear loads approaching 1.6 and 0.6 BW during the follow-through phases. The peak compressive load estimated in this study was high, but less than the corresponding value (over 8 BW) reported by a previous study. Average EMG levels of different muscles were the highest in the acceleration and follow-through phases, suggesting a likely link between co-contractions of paraspinal muscles and lumbar spinal loads.

  1. Stretch activation and nonlinear elasticity of muscle cross-bridges.

    PubMed Central

    Thomas, N; Thornhill, R A

    1996-01-01

    When active insect fibrillar flight muscle is stretched, its ATPase rate increases and it develops "negative viscosity," which allows it to perform oscillatory work. We use a six-state model for the cross-bridge cycle to show that such "stretch activation" may arise naturally as a nonlinear property of a cross-bridge interacting with a single attachment site on a thin filament. Attachment is treated as a thermally activated process in which elastic energy must be supplied to stretch or compress the cross-bridge spring. We find that stretch activation occurs at filament displacements where, before the power stroke, the spring is initially in compression rather than in tension. In that case, pulling the filaments relieves the initial compression and reduces the elastic energy required for attachment. The result is that the attachment rate is enhanced by stretching. The model also displays the "delayed tension" effect observed in length-step experiments. When the muscle is stretched suddenly, the power stroke responds very quickly, but there is a time lag before dissociation at the end of the cycle catches up with the increased attachment rate. This lag is responsible for the delayed tension and hence also for the negative viscosity. PMID:8744318

  2. Serum Fatty Acids, Desaturase Activities and Abdominal Obesity – A Population-Based Study of 60-Year Old Men and Women

    PubMed Central

    Alsharari, Zayed D.; Risérus, Ulf; Leander, Karin; Sjögren, Per; Carlsson, Axel C.; Vikström, Max; Laguzzi, Federica; Gigante, Bruna; Cederholm, Tommy; De Faire, Ulf; Hellénius, Mai-Lis

    2017-01-01

    Abdominal obesity is a key contributor of metabolic disease. Recent trials suggest that dietary fat quality affects abdominal fat content, where palmitic acid and linoleic acid influence abdominal obesity differently, while effects of n-3 polyunsaturated fatty acids are less studied. Also, fatty acid desaturation may be altered in abdominal obesity. We aimed to investigate cross-sectional associations of serum fatty acids and desaturases with abdominal obesity prevalence in a population-based cohort study. Serum cholesteryl ester fatty acids composition was measured by gas chromatography in 60-year old men (n = 1883) and women (n = 2015). Cross-sectional associations of fatty acids with abdominal obesity prevalence and anthropometric measures (e.g., sagittal abdominal diameter) were evaluated in multivariable-adjusted logistic and linear regression models, respectively. Similar models were employed to investigate relations between desaturase activities (estimated by fatty acid ratios) and abdominal obesity. In logistic regression analyses, palmitic acid, stearoyl-CoA-desaturase and Δ6-desaturase indices were associated with abdominal obesity; multivariable-adjusted odds ratios (95% confidence intervals) for highest versus lowest quartiles were 1.45 (1.19–1.76), 4.06 (3.27–5.05), and 3.07 (2.51–3.75), respectively. Linoleic acid, α-linolenic acid, docohexaenoic acid, and Δ5-desaturase were inversely associated with abdominal obesity; multivariable-adjusted odds ratios (95% confidence intervals): 0.39 (0.32–0.48), 0.74 (0.61–0.89), 0.76 (0.62–0.93), and 0.40 (0.33–0.49), respectively. Eicosapentaenoic acid was not associated with abdominal obesity. Similar results were obtained from linear regression models evaluating associations with different anthropometric measures. Sex-specific and linear associations were mainly observed for n3-polyunsaturated fatty acids, while associations of the other exposures were generally non-linear and similar across

  3. Abdominal pain

    MedlinePlus

    Stomach pain; Pain - abdomen; Belly ache; Abdominal cramps; Bellyache; Stomachache ... Almost everyone has pain in the abdomen at some point. Most of the time, it is not serious. How bad your pain is ...

  4. [Abdominal pain].

    PubMed

    Gschossmann, J M; Holtmann, G; Netzer, P; Essig, M; Balsiger, B M; Scheurer, U

    2005-10-01

    Abdominal pain can result from a variety of different intra- and extra-abdominal disorders. Given the wide variety of etiological triggers for this pain, the primary task during the first stage of the diagnostic work-up is to determine as soon as possible the underlying cause and the degree of emergency. The aim of this evaluation is to adapt the therapeutic measures which are necessary for a causal treatment to the individual situation. Contrary to somatic causes of abdominal pain, the availability of such a causal therapy for functional bowel disorders is still very limited. Given this dilemma, the therapeutic focus of abdominal pain associated with these functional syndromes has to be placed on symptom-oriented treatment.

  5. Direct optical activation of skeletal muscle fibres efficiently controls muscle contraction and attenuates denervation atrophy.

    PubMed

    Magown, Philippe; Shettar, Basavaraj; Zhang, Ying; Rafuse, Victor F

    2015-10-13

    Neural prostheses can restore meaningful function to paralysed muscles by electrically stimulating innervating motor axons, but fail when muscles are completely denervated, as seen in amyotrophic lateral sclerosis, or after a peripheral nerve or spinal cord injury. Here we show that channelrhodopsin-2 is expressed within the sarcolemma and T-tubules of skeletal muscle fibres in transgenic mice. This expression pattern allows for optical control of muscle contraction with comparable forces to nerve stimulation. Force can be controlled by varying light pulse intensity, duration or frequency. Light-stimulated muscle fibres depolarize proportionally to light intensity and duration. Denervated triceps surae muscles transcutaneously stimulated optically on a daily basis for 10 days show a significant attenuation in atrophy resulting in significantly greater contractile forces compared with chronically denervated muscles. Together, this study shows that channelrhodopsin-2/H134R can be used to restore function to permanently denervated muscles and reduce pathophysiological changes associated with denervation pathologies.

  6. The effects of shoulder joint abduction angles on the muscle activity of the serratus anterior muscle and the upper trapezius muscle while vibrations are applied.

    PubMed

    Jung, Da-Eun; Moon, Dong-Chul

    2015-01-01

    [Purpose] The purpose of this study was to examine the ratio between the upper trapezius and the serratus anterior muscles during diverse shoulder abduction exercises applied with vibrations in order to determine the appropriate exercise methods for recovery of scapular muscle balance. [Subjects and Methods] Twenty-four subjects voluntarily participated in this study. The subjects performed shoulder abduction at various shoulder joint abduction angles (90°, 120°, 150°, 180°) with oscillation movements. [Results] At 120°, all the subjects showed significant increases in the muscle activity of the serratus anterior muscle in comparison with the upper trapezius muscle. However, no significant difference was found at angles other than 120°. [Conclusion] To selectively strengthen the serratus anterior, applying vibration stimuli at the 120° shoulder abduction position is considered to be appropriate.

  7. Suboptimal Muscle Synergy Activation Patterns Generalize their Motor Function across Postures.

    PubMed

    Sohn, M Hongchul; Ting, Lena H

    2016-01-01

    We used a musculoskeletal model to investigate the possible biomechanical and neural bases of using consistent muscle synergy patterns to produce functional motor outputs across different biomechanical conditions, which we define as generalizability. Experimental studies in cats demonstrate that the same muscle synergies are used during reactive postural responses at widely varying configurations, producing similarly-oriented endpoint force vectors with respect to the limb axis. However, whether generalizability across postures arises due to similar biomechanical properties or to neural selection of a particular muscle activation pattern has not been explicitly tested. Here, we used a detailed cat hindlimb model to explore the set of feasible muscle activation patterns that produce experimental synergy force vectors at a target posture, and tested their generalizability by applying them to different test postures. We used three methods to select candidate muscle activation patterns: (1) randomly-selected feasible muscle activation patterns, (2) optimal muscle activation patterns minimizing muscle effort at a given posture, and (3) generalizable muscle activation patterns that explicitly minimized deviations from experimentally-identified synergy force vectors across all postures. Generalizability was measured by the deviation between the simulated force direction of the candidate muscle activation pattern and the experimental synergy force vectors at the test postures. Force angle deviations were the greatest for the randomly selected feasible muscle activation patterns (e.g., >100°), intermediate for effort-wise optimal muscle activation patterns (e.g., ~20°), and smallest for generalizable muscle activation patterns (e.g., <5°). Generalizable muscle activation patterns were suboptimal in terms of effort, often exceeding 50% of the maximum possible effort (cf. ~5% in minimum-effort muscle activation patterns). The feasible muscle activation ranges of individual

  8. Suboptimal Muscle Synergy Activation Patterns Generalize their Motor Function across Postures

    PubMed Central

    Sohn, M. Hongchul; Ting, Lena H.

    2016-01-01

    We used a musculoskeletal model to investigate the possible biomechanical and neural bases of using consistent muscle synergy patterns to produce functional motor outputs across different biomechanical conditions, which we define as generalizability. Experimental studies in cats demonstrate that the same muscle synergies are used during reactive postural responses at widely varying configurations, producing similarly-oriented endpoint force vectors with respect to the limb axis. However, whether generalizability across postures arises due to similar biomechanical properties or to neural selection of a particular muscle activation pattern has not been explicitly tested. Here, we used a detailed cat hindlimb model to explore the set of feasible muscle activation patterns that produce experimental synergy force vectors at a target posture, and tested their generalizability by applying them to different test postures. We used three methods to select candidate muscle activation patterns: (1) randomly-selected feasible muscle activation patterns, (2) optimal muscle activation patterns minimizing muscle effort at a given posture, and (3) generalizable muscle activation patterns that explicitly minimized deviations from experimentally-identified synergy force vectors across all postures. Generalizability was measured by the deviation between the simulated force direction of the candidate muscle activation pattern and the experimental synergy force vectors at the test postures. Force angle deviations were the greatest for the randomly selected feasible muscle activation patterns (e.g., >100°), intermediate for effort-wise optimal muscle activation patterns (e.g., ~20°), and smallest for generalizable muscle activation patterns (e.g., <5°). Generalizable muscle activation patterns were suboptimal in terms of effort, often exceeding 50% of the maximum possible effort (cf. ~5% in minimum-effort muscle activation patterns). The feasible muscle activation ranges of individual

  9. Posterior scissors-bite: masticatory jaw movement and muscle activity.

    PubMed

    Tomonari, H; Kubota, T; Yagi, T; Kuninori, T; Kitashima, F; Uehara, S; Miyawaki, S

    2014-04-01

    Scissors-bite is a malocclusion characterised by buccal inclination or buccoversion of the maxillary posterior tooth and/or linguoclination or linguoversion of the mandibular posterior tooth. This type of malocclusion causes reduced contact of the occlusal surfaces and can cause excessive vertical overlapping of the posterior teeth. This case-control study is the first to evaluate both masticatory jaw movement and masseter and temporalis muscle activity in patients with unilateral posterior scissors-bite. Jaw movement variables and surface electromyography data were recorded in 30 adult patients with unilateral posterior scissors-bite malocclusion and 18 subjects with normal occlusion in a case-control study. The chewing pattern on the scissors-bite side significantly differed from that of the non-scissors-bite side in the patients and of the right side in the normal subjects. These differences included a narrower chewing pattern (closing angle, P < 0.01; cycle width, P < 0.01), a longer closing duration (P < 0.05), a slower closing velocity (P < 0.01) and lower activities of both the temporalis (P < 0.05) and the masseter (P < 0.05) muscles on the working side. In 96% of the patients with unilateral posterior scissors-bite, the preferred chewing side was the non-scissors-bite side (P = 0.005). These findings suggest that scissors-bite malocclusion is associated with the masticatory chewing pattern and muscle activity, involving the choice of the preferred chewing side in patients with unilateral posterior scissors-bite.

  10. Passive resting state and history of antagonist muscle activity shape active extensions in an insect limb

    PubMed Central

    Ache, Jan M.

    2012-01-01

    Limb movements can be driven by muscle contractions, external forces, or intrinsic passive forces. For lightweight limbs like those of insects or small vertebrates, passive forces can be large enough to overcome the effects of gravity and may even generate limb movements in the absence of active muscle contractions. Understanding the sources and actions of such forces is therefore important in understanding motor control. We describe passive properties of the femur-tibia joint of the locust hind leg. The resting angle is determined primarily by passive properties of the relatively large extensor tibiae muscle and is influenced by the history of activation of the fast extensor tibiae motor neuron. The resting angle is therefore better described as a history-dependent resting state. We selectively stimulated different flexor tibiae motor neurons to generate a range of isometric contractions of the flexor tibiae muscle and then stimulated the fast extensor tibiae motor neuron to elicit active tibial extensions. Residual forces in the flexor muscle have only a small effect on subsequent active extensions, but the effect is larger for distal than for proximal flexor motor neurons and varies with the strength of flexor activation. We conclude that passive properties of a lightweight limb make substantial and complex contributions to the resting state of the limb that must be taken into account in the patterning of neuronal control signals driving its active movements. Low variability in the effects of the passive forces may permit the nervous system to accurately predict their contributions to behavior. PMID:22357791

  11. Synthetic muscle promoters: activities exceeding naturally occurring regulatory sequences

    NASA Technical Reports Server (NTRS)

    Li, X.; Eastman, E. M.; Schwartz, R. J.; Draghia-Akli, R.

    1999-01-01

    Relatively low levels of expression from naturally occurring promoters have limited the use of muscle as a gene therapy target. Myogenic restricted gene promoters display complex organization usually involving combinations of several myogenic regulatory elements. By random assembly of E-box, MEF-2, TEF-1, and SRE sites into synthetic promoter recombinant libraries, and screening of hundreds of individual clones for transcriptional activity in vitro and in vivo, several artificial promoters were isolated whose transcriptional potencies greatly exceed those of natural myogenic and viral gene promoters.

  12. [Impact of abdominal cavity open EHF irradiation on activity of adhesive process in peritonitis].

    PubMed

    Boĭko, V V; Ivanova, Iu V; Gamidov, A N; Andreeshchev, S A

    2015-01-01

    In experiment on 45 rats a purulent peritonitis was simulated. There was established, that on background of a standard therapy for peritonitis application of abdominal cavity open irradiation of extreme high frequency (EHF) have promoted rapid stabilization of the lipid metabolism indices and the blood coagulation system, the reduction of intensity of lipids peroxidal oxidation processes and severity of systemic inflammatory reaction. Under the influence of complex treatment the severity of adhesive process was reduced in 5.4 times, comparing with such in animals, to whom a standard treatment was conducted only. The revealed pathogenetic aspects of the adhesions formation witnesses the expediency to add EHF irradiation to complex therapy of peritonitis.

  13. Associations between personality traits, physical activity level, and muscle strength.

    PubMed

    Tolea, Magdalena I; Terracciano, Antonio; Simonsick, Eleanor M; Metter, E Jeffrey; Costa, Paul T; Ferrucci, Luigi

    2012-06-01

    Associations among personality as measured by the Five Factor Model, physical activity, and muscle strength were assessed using data from the Baltimore Longitudinal Study of Aging (N = 1220, age: mean = 58, SD = 16). General linear modeling with adjustment for age, sex, race, and body mass index, and bootstrapping for mediation were used. We found neuroticism and most of its facets to negatively correlate with strength. The extraversion domain and its facets of warmth, activity, and positive-emotions were positively correlated with strength, independent of covariates. Mediation analysis results suggest that these associations are partly explained by physical activity level. Findings extend the evidence of an association between personality and physical function to its strength component and indicate health behavior as an important pathway.

  14. Neck and shoulder muscle activity during standardized work-related postural tasks.

    PubMed

    Ng, D; McNee, C; Kieser, J; Farella, M

    2014-05-01

    The aim of the present study was to assess the activity levels of the sternocleidomastoid muscle and upper trapezius muscle during static postures under controlled and standardized conditions, and to determine whether the muscle activity differed between sexes. Electromyographic (EMG) activity was recorded unilaterally from the sternocleidomastoid and upper trapezius muscle in 17 participants whilst they were performing various postural tasks. EMG amplitude was measured by the root mean square values of the raw signals and normalized to peak maximum contractile values for each muscle (%MVC). The intensity of muscle activity was ranked as light (<3%MVC), moderate (3%MVC ≤ EMG ≤ 8%MVC), and substantial (>8%MVC). During most tasks the two muscles contracted light to moderately. Head leaning and shoulder shrugging postures yielded substantial muscle activity in both muscles. Muscle activity did not differ significantly between male and female participants (F = 3.1; p = 0.078). Our findings provided normative values, which will enhance future studies of muscle activity during work in a natural, unrestrained environment.

  15. Endovascular Repair of an Actively Hemorrhaging Stab Wound Injury to the Abdominal Aorta

    SciTech Connect

    Hussain, Qasim; Maleux, Geert Heye, Sam; Fourneau, Inge

    2008-09-15

    Traumatic injury of the abdominal aorta is rare and potentially lethal (Yeh et al., J Vasc Surg 42(5):1007-1009, 2005; Chicos et al., Chirurgia (Bucur) 102(2):237-240, 2007) as it can result in major retroperitoneal hemorrhage, requiring an urgent open surgery. In case of concomitant bowel injury or other conditions of hostile abdomen, endovascular repair can be an alternative treatment. This case report deals with a 50-year-old man presenting at the emergency ward with three stab wounds: two in the abdomen and one in the chest. During explorative laparotomy, liver laceration and bowel perforation were repaired. One day later, abdominal CT-scan revealed an additional retroperitoneal hematoma associated with an aortic pseudoaneurysm, located anteriorly 3 cm above the aortic bifurcation. Because of the risk of graft infection, an endovascular repair of the aortic injury using a Gore excluder stent-graft was performed. Radiological and clinical follow-up revealed a gradual shrinkage of the pseudo-aneurysm and no sign of graft infection at two years' follow-up.

  16. The Regulation of Skeletal Muscle Active Hyperemia: The Differential Role of Adenosine in Muscles of Varied Fiber Types

    DTIC Science & Technology

    1986-04-21

    0.2 Hz and three mnscles ~;timulated to contract at 0.4 Hz during BADA infuston. These m~tabolites were also mea~•1red in two muscles contractin ~ at...APR 1986 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE The Regulation of Skeletal Muscle Active Hyperemia: The Differential...Role of Adenosine in Muscles of Varied Fiber Types 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER

  17. Glycogen synthesis from lactate in a chronically active muscle

    SciTech Connect

    Talmadge, R.J.; Scheide, J.I.; Silverman, H.

    1989-05-01

    In response to neural overactivity (pseudomyotonia), gastrocnemius muscle fibers from C57Bl/6Jdy2J/dy2J mice have different metabolic profiles compared with normal mice. A population of fibers in the fast-twitch superficial region of the dy2J gastrocnemius stores unusually high amounts of glycogen, leading to an increased glycogen storage in the whole muscle. The dy2J muscle also contains twice as much lactate as normal muscle. A (/sup 14/C)lactate intraperitoneal injection leads to preferential /sup 14/C incorporation into glycogen in the dy2J muscle compared with normal muscle. To determine whether skeletal muscles were incorporating lactate into glycogen without body organ (liver, kidney) input, gastrocnemius muscles were bathed in 10 mM (/sup 14/C)lactate with intact neural and arterial supply but with impeded venous return. The contralateral gastrocnemius serves as a control for body organ input. By using this in situ procedure, we demonstrate that under conditions of high lactate both normal and dy2J muscle can directly synthesize glycogen from lactate. In this case, normal whole muscle incorporates (14C) lactate into glycogen at a higher rate than dy2J whole muscle. Autoradiography, however, suggests that the high-glycogen-containing muscle fibers in the dy2J muscle incorporate lactate into glycogen at nearly four times the rate of normal or surrounding muscle fibers.

  18. The production of denervation-like changes in rat muscle by colchicine, without interference with axonal transport or muscle activity.

    PubMed Central

    Cangiano, A; Fried, J A

    1977-01-01

    1. Rat extensor digitorum longus (EDL) muscles were examined after colchicine treatment of the sciatic nerve. Colchicine was applied in one of two ways: (i) a single sub-epineural injection; (ii) a chronically implanted silicone cuff. 2. After the sub-epineural injection, the entire membrane of muscle fibres became sensitive to iontophoretically applied acetylcholine and the muscle action potentials became resistant to tetrodotoxin. However, the majority of these fibres were found to be normally innervated. 3. These effects were not restricted to the EDL muscle of the colchicine injected side but were also found in the EDL muscle of the contralateral side, indicating that the action of colchicine was systemic. 4. In the treated sciatic nerve there was a partial block of axonal transport of 3H-labelled proteins, which correlated with a partial paralysis of the ipsilateral leg. However, axoplasmic transport was found to be normal in the contralateral sciatic nerve and the contralateral limb was not paralysed despite the supersensitivity of the investigated muscle on that side. 5. When colchicine was applied with a silicone cuff, denervation-like changes were confined to the ipsilateral EDL muscle. However, impulse conduction block at the level of the cuff was usually observed. 6. It is concluded that (i) colchicine can produce denervation-like changes in normally active muscle without blocking axoplasmic transport, through an action probably exerted directly on the muscle membrane, and (ii) that colchicine-cuff experiments failed to provide unambiguous evidence in support of the existence of neurotrophic influences on the muscle membrane. PMID:66309

  19. Nervous factors influencing the membrane activity of intestinal smooth muscle

    PubMed Central

    Kuriyama, H.; Osa, T.; Toida, N.

    1967-01-01

    The effects of various chemical agents on the spontaneous membrane activities and those electrically elicited in the smooth muscles of small intestine were investigated. 1. The effects of various chemicals on the spontaneously active membrane might be summarized as follows. (a) Cholinergic agents; atropine slightly hyperpolarized the membrane and reduced the amplitude of slow potential changes even in aged preparations. Prostigmine depolarized the membrane, and enhanced the amplitude and prolonged the duration of the slow potential changes. Atropine prevented the actions of prostigmine on the membrane. (b) Ba2+ depolarized the membrane, and enhanced the amplitude and prolonged the duration of the slow potential changes. The spike frequency was initially increased, then reduced. Atropine and tetrodotoxin partially prevented the action of Ba2+ on the membrane activities. 2. Effects of chemical agents on the membrane activity elicited by electrical stimulation might be summarized as follows. (a) Short pulse stimulation (0·5-1 msec) generated the spike as a direct response of the muscle cell membrane, then it was followed by slow depolarization, delayed hyperpolarization, i.e. the `inhibitory potential', and post-inhibitory rebound successively. (b) The slow depolarization and the post-inhibitory rebound were reduced in amplitude by treatment with atropine, and enhanced by treatments with prostigmine and Ba2+. Tetrodotoxin blocked all activities except the spike. 3. When repetitive stimulation (20 c/s) was applied to the membrane, the membrane hyperpolarized; then, after 3-5 sec, it gradually depolarized even if the stimulation was continued, and triggered spikes. The hyperpolarization always preceded depolarization. The duration and the amplitude of the delayed depolarization was proportionally increased by the increased intensity and duration of stimulation. Atropine and tetrodotoxin blocked the generation of the post-inhibitory rebound. 4. Effects of repetitive

  20. Masseter Muscle Activity in Track and Field Athletes: A Pilot Study.

    PubMed

    Nukaga, Hideyuki; Takeda, Tomotaka; Nakajima, Kazunori; Narimatsu, Keishiro; Ozawa, Takamitsu; Ishigami, Keiichi; Funato, Kazuo

    2016-01-01

    Teeth clenching has been shown to improve remote muscle activity (by augmentation of the Hoffmann reflex), and joint fixation (by decreased reciprocal inhibition) in the entire body. Clenching could help maintain balance, improve systemic function, and enhance safety. Teeth clenching from a sports dentistry viewpoint was thought to be important and challenging. Therefore, it is quite important to investigate mastication muscles' activity and function during sports events for clarifying a physiological role of the mastication muscle itself and involvement of mastication muscle function in whole body movement. Running is a basic motion of a lot of sports; however, a mastication muscles activity during this motion was not clarified. Throwing and jumping operation were in a same situation. The purpose of this study was to investigate the presence or absence of masseter muscle activity during track and field events. In total, 28 track and field athletes took part in the study. The Multichannel Telemetry system was used to monitor muscle activity, and the electromyograms obtained were synchronized with digital video imaging. The masseter muscle activity threshold was set 15% of maximum voluntary clenching. As results, with few exceptions, masseter muscle activity were observed during all analyzed phases of the 5 activities, and that phases in which most participants showed masseter muscle activity were characterized by initial acceleration, such as in the short sprint, from the commencement of throwing to release in both the javelin throw and shot put, and at the take-off and landing phases in both jumps.

  1. Cortical activation associated with muscle synergies of the human male pelvic floor.

    PubMed

    Asavasopon, Skulpan; Rana, Manku; Kirages, Daniel J; Yani, Moheb S; Fisher, Beth E; Hwang, Darryl H; Lohman, Everett B; Berk, Lee S; Kutch, Jason J

    2014-10-08

    Human pelvic floor muscles have been shown to operate synergistically with a wide variety of muscles, which has been suggested to be an important contributor to continence and pelvic stability during functional tasks. However, the neural mechanism of pelvic floor muscle synergies remains unknown. Here, we test the hypothesis that activation in motor cortical regions associated with pelvic floor activation are part of the neural substrate for such synergies. We first use electromyographic recordings to extend previous findings and demonstrate that pelvic floor muscles activate synergistically during voluntary activation of gluteal muscles, but not during voluntary activation of finger muscles. We then show, using functional magnetic resonance imaging (fMRI), that a region of the medial wall of the precentral gyrus consistently activates during both voluntary pelvic floor muscle activation and voluntary gluteal activation, but not during voluntary finger activation. We finally confirm, using transcranial magnetic stimulation, that the fMRI-identified medial wall region is likely to generate pelvic floor muscle activation. Thus, muscle synergies of the human male pelvic floor appear to involve activation of motor cortical areas associated with pelvic floor control.

  2. Cortical Activation Associated with Muscle Synergies of the Human Male Pelvic Floor

    PubMed Central

    Asavasopon, Skulpan; Rana, Manku; Kirages, Daniel J.; Yani, Moheb S.; Fisher, Beth E.; Hwang, Darryl H.; Lohman, Everett B.; Berk, Lee S.

    2014-01-01

    Human pelvic floor muscles have been shown to operate synergistically with a wide variety of muscles, which has been suggested to be an important contributor to continence and pelvic stability during functional tasks. However, the neural mechanism of pelvic floor muscle synergies remains unknown. Here, we test the hypothesis that activation in motor cortical regions associated with pelvic floor activation are part of the neural substrate for such synergies. We first use electromyographic recordings to extend previous findings and demonstrate that pelvic floor muscles activate synergistically during voluntary activation of gluteal muscles, but not during voluntary activation of finger muscles. We then show, using functional magnetic resonance imaging (fMRI), that a region of the medial wall of the precentral gyrus consistently activates during both voluntary pelvic floor muscle activation and voluntary gluteal activation, but not during voluntary finger activation. We finally confirm, using transcranial magnetic stimulation, that the fMRI-identified medial wall region is likely to generate pelvic floor muscle activation. Thus, muscle synergies of the human male pelvic floor appear to involve activation of motor cortical areas associated with pelvic floor control. PMID:25297107

  3. Child—Adult Differences in Muscle Activation — A Review

    PubMed Central

    Dotan, Raffy; Mitchell, Cameron; Cohen, Rotem; Klentrou, Panagiota; Gabriel, David; Falk, Bareket

    2013-01-01

    Children differ from adults in many muscular performance attributes such as size-normalized strength and power, endurance, fatigability and the recovery from exhaustive exercise, to name just a few. Metabolic attributes, such as glycolytic capacity, substrate utilization, and VO2 kinetics also differ markedly between children and adults. Various factors, such as dimensionality, intramuscular synchronization, agonist-antagonist coactivation, level of volitional activation, or muscle composition, can explain some, but not all of the observed differences. It is hypothesized that, compared with adults, children are substantially less capable of recruiting or fully employing their higher-threshold, type-II motor units. The review presents and evaluates the wealth of information and possible alternative factors in explaining the observations. Although conclusive evidence is still lacking, only this hypothesis of differential motor-unit activation in children and adults, appears capable of accounting for all observed child—adult differences, whether on its own or in conjunction with other factors. PMID:22433260

  4. Simulating the activation, contraction and movement of skeletal muscles using the bidomain model.

    PubMed

    Lopez Rincon, A; Cantu, C; Soto, R; Shimoda, S

    2016-08-01

    A simulation of the muscle activation, contraction and movement is here presented. This system was developed based on the Bidomain mathematical model of the electrical propagation in muscles. This study shows an electrical stimuli input to a muscle and how this behave. The comparison between healthy subject and patient with muscle activation impairment is depicted, depending on whether the signal reaches a threshold. A 3D model of a bicep muscle and a forearm bone connected was constructed using OpenGL. This platform could be used for development of controllers for biomechatronic systems in future works. This kind of bioinspired model could be used for a better understanding of the neuromotor system.

  5. Plasma fatty acid composition, estimated desaturase activities, and intakes of energy and nutrient in Japanese men with abdominal obesity or metabolic syndrome.

    PubMed

    Kawashima, Aiko; Sugawara, Shiori; Okita, Misako; Akahane, Takemi; Fukui, Kennichi; Hashiuchi, Maiko; Kataoka, Chieko; Tsukamoto, Ikuyo

    2009-01-01

    To examine predictive factors for abdominal obesity or metabolic syndrome, we investigated the association of plasma fatty acid composition, estimated desaturase activity, and nutrient intakes, with abdominal obesity or metabolic syndrome in Japanese males. Clinical characteristics, the fatty acid composition of plasma cholesteryl esters, and energy and nutrient intakes were analyzed in 3 groups: metabolic syndrome (MS, n=24), abdominal obesity (OB, n=43), and control (n=27). The estimated desaturase activities were calculated by the ratio of 16:1n-7/16:0, 18:3n-6/18:2n-6, and 20:4n-6/20:3n-6 in plasma cholesteryl esters as surrogates of the measure of the delta 9, delta 6, delta 5 desaturase (D9-16D, D6D and D5D) activities, respectively. Plasma fatty acid composition did not differ significantly between the OB group and the control group. The MS group had higher levels of palmitoleic, oleic, and gamma-linolenic acids, but a lower level of linoleic acid than the control. Stronger D6D activity and weaker D5D activity were observed in the OB group. A higher level of D9-16D activity as well as a higher level of D6D activity and a lower level of D5D activity was observed in the MS group. A logistic regression analysis showed that the low D5D activity and high D9-16D activity were predictive of the development of abdominal obesity from controls (odds ratio=0.39, p<0.05) and metabolic syndrome from abdominal obesity (odds ratio=2.44, p<0.05), respectively. In the multiple linear regression analysis, D5D activity positively correlated with the intake of eicosapentaenoic acid (EPA). In conclusion, the estimated D5D activity was a predictive factor for abdominal obesity and the estimated D9-16D activity was a predictive factor for developing metabolic syndrome from abdominal obesity in Japanese male subjects. Dietary intake of EPA would play an important role in preventing abdominal obesity and the development of metabolic syndrome.

  6. Abdominal Sepsis.

    PubMed

    De Waele, Jan J

    2016-08-01

    Abdominal infections are an important challenge for the intensive care physician. In an era of increasing antimicrobial resistance, selecting the appropriate regimen is important and, with new drugs coming to the market, correct use is important more than ever before and abdominal infections are an excellent target for antimicrobial stewardship programs. Biomarkers may be helpful, but their exact role in managing abdominal infections remains incompletely understood. Source control also remains an ongoing conundrum, and evidence is increasing that its importance supersedes the impact of antibiotic therapy. New strategies such as open abdomen management may offer added benefit in severely ill patients, but more data are needed to identify its exact role. The role of fungi and the need for antifungal coverage, on the other hand, have been investigated extensively in recent years, but at this point, it remains unclear who requires empirical as well as directed therapy.

  7. Transcriptional activation of muscle atrophy promotes cardiac muscle remodeling during mammalian hibernation

    PubMed Central

    Zhang, Yichi; Aguilar, Oscar A.

    2016-01-01

    during late torpor by 2.4-fold. Protein levels of MAFbx and MuRF1 increased in late torpor as well as during early arousal by as much as 2.8-fold, and MAFbx levels remained elevated during interbout arousal, whereas MuRF1 levels returned to control levels. Discussion. The present results indicate that upregulation and activation of Foxo1 and 3a, in addition to the increase in MyoG levels at late torpor, may be upregulating the expression of MAFbx and MuRF1. These findings suggest that there is activation of the ubiquitin proteasome system (UPS) as ground squirrels arouse from torpor. Therefore, the signalling pathway involving MyoG, and the E3 ligases MAFbx and MuRF1, plays a significant role in cardiac muscle remodelling during hibernation. These findings provide insights into the regulation of protein degradation and turnover in the cardiac muscle of a hibernator model. PMID:27602284

  8. Muscle networks: Connectivity analysis of EMG activity during postural control

    NASA Astrophysics Data System (ADS)

    Boonstra, Tjeerd W.; Danna-Dos-Santos, Alessander; Xie, Hong-Bo; Roerdink, Melvyn; Stins, John F.; Breakspear, Michael

    2015-12-01

    Understanding the mechanisms that reduce the many degrees of freedom in the musculoskeletal system remains an outstanding challenge. Muscle synergies reduce the dimensionality and hence simplify the control problem. How this is achieved is not yet known. Here we use network theory to assess the coordination between multiple muscles and to elucidate the neural implementation of muscle synergies. We performed connectivity analysis of surface EMG from ten leg muscles to extract the muscle networks while human participants were standing upright in four different conditions. We observed widespread connectivity between muscles at multiple distinct frequency bands. The network topology differed significantly between frequencies and between conditions. These findings demonstrate how muscle networks can be used to investigate the neural circuitry of motor coordination. The presence of disparate muscle networks across frequencies suggests that the neuromuscular system is organized into a multiplex network allowing for parallel and hierarchical control structures.

  9. A cyclic AMP-activated K+ channel in Drosophila larval muscle is persistently activated in dunce.

    PubMed

    Delgado, R; Hidalgo, P; Diaz, F; Latorre, R; Labarca, P

    1991-01-15

    Single-channel recording from longitudinal ventrolateral Drosophila larval muscle reveals the presence of a potassium-selective channel that is directly and reversibly activated by cAMP in a dose-dependent fashion. Activation is specific and it cannot be mimicked by a series of agents that include AMP, cGMP, ATP, inositol trisphosphate, and Ca2+. Channel current records obtained from larval muscle in different dunce mutants possessing abnormally high levels of cAMP show that, in the mutants, the channel displays an increased probability of opening.

  10. A cyclic AMP-activated K+ channel in Drosophila larval muscle is persistently activated in dunce.

    PubMed Central

    Delgado, R; Hidalgo, P; Diaz, F; Latorre, R; Labarca, P

    1991-01-01

    Single-channel recording from longitudinal ventrolateral Drosophila larval muscle reveals the presence of a potassium-selective channel that is directly and reversibly activated by cAMP in a dose-dependent fashion. Activation is specific and it cannot be mimicked by a series of agents that include AMP, cGMP, ATP, inositol trisphosphate, and Ca2+. Channel current records obtained from larval muscle in different dunce mutants possessing abnormally high levels of cAMP show that, in the mutants, the channel displays an increased probability of opening. PMID:1846445

  11. Muscle activity and co-contraction of musculoskeletal model during steering maneuver.

    PubMed

    Gao, Zhen-hai; Fan, Da; Wang, Deping; Zhao, Hui; Zhao, Kaishu; Chen, Chaoyang

    2014-01-01

    In this study a musculoskeletal model of driver steering maneuver was established. The model was driven by the steering angle and steering torque when performing typical steering test. The simulation was calculated using inverse dynamics. Maximum muscle activity and the muscle activity of each muscle were studied afterwards. The key muscles that generated steering torque were scapular portion of deltoid, infraspinatus, latissimus dorsi, subscapularis, triceps long head and triceps lateral head. Muscle co-contraction was analyzed quantitatively and was significantly different from muscle activity. This paper presents a preliminary research on the mechanical properties of upper limb muscles during steering maneuver. The results can serve as references for vehicle design and performance evaluation using the physiological characteristics of drivers.

  12. Problems with extracellular recording of electrical activity in gastrointestinal muscle.

    PubMed

    Sanders, Kenton M; Ward, Sean M; Hennig, Grant W

    2016-12-01

    Motility patterns of the gastrointestinal tract are important for efficient processing of nutrients and waste. Peristalsis and segmentation are based on rhythmic electrical slow waves that generate the phasic contractions fundamental to gastrointestinal motility. Slow waves are generated and propagated actively by interstitial cells of Cajal (ICC), and these events conduct to smooth muscle cells to elicit excitation-contraction coupling. Extracellular electrical recording has been utilized to characterize slow-wave generation and propagation and abnormalities that might be responsible for gastrointestinal motility disorders. Electrode array recording and digital processing are being used to generate data for models of electrical propagation in normal and pathophysiological conditions. Here, we discuss techniques of extracellular recording as applied to gastrointestinal organs and how mechanical artefacts might contaminate these recordings and confound their interpretation. Without rigorous controls for movement, current interpretations of extracellular recordings might ascribe inaccurate behaviours and electrical anomalies to ICC networks and gastrointestinal muscles, bringing into question the findings and validity of models of gastrointestinal electrophysiology developed from these recordings.

  13. The Abdominal Circulatory Pump

    PubMed Central

    Aliverti, Andrea; Bovio, Dario; Fullin, Irene; Dellacà, Raffaele L.; Lo Mauro, Antonella; Pedotti, Antonio; Macklem, Peter T.

    2009-01-01

    Blood in the splanchnic vasculature can be transferred to the extremities. We quantified such blood shifts in normal subjects by measuring trunk volume by optoelectronic plethysmography, simultaneously with changes in body volume by whole body plethysmography during contractions of the diaphragm and abdominal muscles. Trunk volume changes with blood shifts, but body volume does not so that the blood volume shifted between trunk and extremities (Vbs) is the difference between changes in trunk and body volume. This is so because both trunk and body volume change identically with breathing and gas expansion or compression. During tidal breathing Vbs was 50–75 ml with an ejection fraction of 4–6% and an output of 750–1500 ml/min. Step increases in abdominal pressure resulted in rapid emptying presumably from the liver with a time constant of 0.61±0.1SE sec. followed by slower flow from non-hepatic viscera. The filling time constant was 0.57±0.09SE sec. Splanchnic emptying shifted up to 650 ml blood. With emptying, the increased hepatic vein flow increases the blood pressure at its entry into the inferior vena cava (IVC) and abolishes the pressure gradient producing flow between the femoral vein and the IVC inducing blood pooling in the legs. The findings are important for exercise because the larger the Vbs the greater the perfusion of locomotor muscles. During asystolic cardiac arrest we calculate that appropriate timing of abdominal compression could produce an output of 6 L/min. so that the abdominal circulatory pump might act as an auxiliary heart. PMID:19440240

  14. Predicting the activation states of the muscles governing upper esophageal sphincter relaxation and opening

    PubMed Central

    Jones, Corinne A.; Hammer, Michael J.; Cock, Charles; Dinning, Philip; Wiklendt, Lukasz; Costa, Marcello; McCulloch, Timothy M.

    2016-01-01

    The swallowing muscles that influence upper esophageal sphincter (UES) opening are centrally controlled and modulated by sensory information. Activation and deactivation of neural inputs to these muscles, including the intrinsic cricopharyngeus (CP) and extrinsic submental (SM) muscles, results in their mechanical activation or deactivation, which changes the diameter of the lumen, alters the intraluminal pressure, and ultimately reduces or promotes flow of content. By measuring the changes in diameter, using intraluminal impedance, and the concurrent changes in intraluminal pressure, it is possible to determine when the muscles are passively or actively relaxing or contracting. From these “mechanical states” of the muscle, the neural inputs driving the specific motor behaviors of the UES can be inferred. In this study we compared predictions of UES mechanical states directly with the activity measured by electromyography (EMG). In eight subjects, pharyngeal pressure and impedance were recorded in parallel with CP- and SM-EMG activity. UES pressure and impedance swallow profiles correlated with the CP-EMG and SM-EMG recordings, respectively. Eight UES muscle states were determined by using the gradient of pressure and impedance with respect to time. Guided by the level and gradient change of EMG activity, mechanical states successfully predicted the activity of the CP muscle and SM muscle independently. Mechanical state predictions revealed patterns consistent with the known neural inputs activating the different muscles during swallowing. Derivation of “activation state” maps may allow better physiological and pathophysiological interpretations of UES function. PMID:26767985

  15. Force regulation of ankle extensor muscle activity in freely walking cats.

    PubMed

    Donelan, J M; McVea, D A; Pearson, K G

    2009-01-01

    To gain insight into the relative importance of force feedback to ongoing ankle extensor activity during walking in the conscious cat, we isolated the medial gastrocnemius muscle (MG) by denervating the other ankle extensors and measured the magnitude of its activity at different muscle lengths, velocities, and forces accomplished by having the animals walk up and down a sloped pegway. Mathematical models of proprioceptor dynamics predicted afferent activity and revealed that the changes in muscle activity under our experimental conditions were strongly correlated with Ib activity and not consistently associated with changes in Ia or group II activity. This allowed us to determine the gains within the force feedback pathway using a simple model of the neuromuscular system and the measured relationship between MG activity and force. Loop gain increased with muscle length due to the intrinsic force-length property of muscle. The gain of the pathway that converts muscle force to motoneuron depolarization was independent of length. To better test for a causal relationship between modulation of force feedback and changes in muscle activity, a second set of experiments was performed in which the MG muscle was perturbed during ground contact of the hind foot by dropping or lifting the peg underfoot. Collectively, these investigations support a causal role for force feedback and indicate that about 30% of the total muscle activity is due to force feedback during level walking. Force feedback's role increases during upslope walking and decreases during downslope walking, providing a simple mechanism for compensating for changes in terrain.

  16. Masseter Muscle Activity in Track and Field Athletes: A Pilot Study

    PubMed Central

    Nukaga, Hideyuki; Takeda, Tomotaka; Nakajima, Kazunori; Narimatsu, Keishiro; Ozawa, Takamitsu; Ishigami, Keiichi; Funato, Kazuo

    2016-01-01

    Teeth clenching has been shown to improve remote muscle activity (by augmentation of the Hoffmann reflex), and joint fixation (by decreased reciprocal inhibition) in the entire body. Clenching could help maintain balance, improve systemic function, and enhance safety. Teeth clenching from a sports dentistry viewpoint was thought to be important and challenging. Therefore, it is quite important to investigate mastication muscles’ activity and function during sports events for clarifying a physiological role of the mastication muscle itself and involvement of mastication muscle function in whole body movement. Running is a basic motion of a lot of sports; however, a mastication muscles activity during this motion was not clarified. Throwing and jumping operation were in a same situation. The purpose of this study was to investigate the presence or absence of masseter muscle activity during track and field events. In total, 28 track and field athletes took part in the study. The Multichannel Telemetry system was used to monitor muscle activity, and the electromyograms obtained were synchronized with digital video imaging. The masseter muscle activity threshold was set 15% of maximum voluntary clenching. As results, with few exceptions, masseter muscle activity were observed during all analyzed phases of the 5 activities, and that phases in which most participants showed masseter muscle activity were characterized by initial acceleration, such as in the short sprint, from the commencement of throwing to release in both the javelin throw and shot put, and at the take-off and landing phases in both jumps. PMID:27708727

  17. [Participation of the primary motor cortex in programming of muscle activity during catching of falling object].

    PubMed

    Kazennikov, O V; Lipshits, M I

    2011-01-01

    Object fell into the cup that sitting subject held between thumb and index fingers. Transcranial magnetic stimulation (TMS) of the primary motor cortex was performed early before and during anticipatory grip force increasing. Comparison of current EMG activity of adductor pollicis brevis and first dorsal interosseous muscles and responses of these muscles on TMS showed that responses were increased before the raising of muscle activity. From the other side only slight augmentation of responses was observed during subsequent strong muscle activation. It is assumed that the increasing of the TMS responses that occurred before the initiation of muscle activity reflects the enhancement ofthe motor cortex excitability associated to specific processes related to the motor cortex participation in programming of the muscles activities.

  18. Differential activation of an identified motor neuron and neuromodulation provide Aplysia's retractor muscle an additional function.

    PubMed

    McManus, Jeffrey M; Lu, Hui; Cullins, Miranda J; Chiel, Hillel J

    2014-08-15

    To survive, animals must use the same peripheral structures to perform a variety of tasks. How does a nervous system employ one muscle to perform multiple functions? We addressed this question through work on the I3 jaw muscle of the marine mollusk Aplysia californica's feeding system. This muscle mediates retraction of Aplysia's food grasper in multiple feeding responses and is innervated by a pool of identified neurons that activate different muscle regions. One I3 motor neuron, B38, is active in the protraction phase, rather than the retraction phase, suggesting the muscle has an additional function. We used intracellular, extracellular, and muscle force recordings in several in vitro preparations as well as recordings of nerve and muscle activity from intact, behaving animals to characterize B38's activation of the muscle and its activity in different behavior types. We show that B38 specifically activates the anterior region of I3 and is specifically recruited during one behavior, swallowing. The function of this protraction-phase jaw muscle contraction is to hold food; thus the I3 muscle has an additional function beyond mediating retraction. We additionally show that B38's typical activity during in vivo swallowing is insufficient to generate force in an unmodulated muscle and that intrinsic and extrinsic modulation shift the force-frequency relationship to allow contraction. Using methods that traverse levels from individual neuron to muscle to intact animal, we show how regional muscle activation, differential motor neuron recruitment, and neuromodulation are key components in Aplysia's generation of multifunctionality.

  19. Activity of trunk muscles during aquatic and terrestrial locomotion in Ambystoma maculatum.

    PubMed

    Deban, Stephen M; Schilling, Nadja

    2009-09-15

    The activity of seven trunk muscles was recorded at two sites along the trunk in adult spotted salamander, Ambystoma maculatum, during swimming and during trotting in water and on land. Several muscles showed patterns of activation that are consistent with the muscles producing a traveling wave of lateral bending during swimming and a standing wave of bending during aquatic and terrestrial trotting: the dorsalis trunci, subvertebralis lateralis and medialis, rectus lateralis and obliquus internus. The interspinalis showed a divergent pattern and was active out of phase with the other muscles suggesting that it functions in vertebral stabilization rather than lateral bending. The obliquus internus and rectus abdominis showed bilateral activity indicating that they counteract sagittal extension of the trunk that is produced when the large dorsal muscles are active to produce lateral bending. Of the muscles examined, only the obliquus internus showed a clear shift in function from lateral bending during swimming to resistance of long-axis torsion during trotting. During terrestrial trotting, muscle recruitment was greater in several muscles than during aquatic trotting, despite similar temporal patterns of muscle activation, suggesting that the trunk is stiffened during terrestrial locomotion against greater gravitational forces whereas the basic functions of the trunk muscles in trotting are conserved across environments.

  20. The association between premature plantarflexor muscle activity, muscle strength, and equinus gait in patients with various pathologies.

    PubMed

    Schweizer, Katrin; Romkes, Jacqueline; Brunner, Reinald

    2013-09-01

    This study provides an overview on the association between premature plantarflexor muscle activity (PPF), muscle strength, and equinus gait in patients with various pathologies. The purpose was to evaluate whether muscular weakness and biomechanical alterations are aetiological factors for PPF during walking, independent of the underlying pathology. In a retrospective design, 716 patients from our clinical database with 46 different pathologies (orthopaedic and neurologic) were evaluated. Gait analysis data of the patients included kinematics, kinetics, electromyographic activity (EMG) data, and manual muscle strength testing. All patients were clustered three times. First, patients were grouped according to their primary pathology. Second, all patients were again clustered, this time according to their impaired joints. Third, groups of patients with normal EMG or PPF, and equinus or normal foot contact were formed to evaluate the association between PPF and equinus gait. The patient groups derived by the first two cluster methods were further subdivided into patients with normal or reduced muscle strength. Additionally, the phi correlation coefficient was calculated between PPF and equinus gait. Independent of the clustering, PPF was present in all patient groups. Weak patients revealed PPF more frequently. The correlations of PPF and equinus gait were lower than expected, due to patients with normal EMG during loading response and equinus. These patients, however, showed higher gastrocnemius activity prior to foot strike together with lower peak tibialis anterior muscle activity in loading response. Patients with PPF and a normal foot contact possibly apply the plantarflexion-knee extension couple during loading response. While increased gastrocnemius activity around foot strike seems essential for equinus gait, premature gastrocnemius activity does not necessarily produce an equinus gait. We conclude that premature gastrocnemius activity is strongly associated

  1. Intra-session repeatability of lower limb muscles activation pattern during pedaling.

    PubMed

    Dorel, Sylvain; Couturier, Antoine; Hug, François

    2008-10-01

    Assessment of intra-session repeatability of muscle activation pattern is of considerable relevance for research settings, especially when used to determine changes over time. However, the repeatability of lower limb muscles activation pattern during pedaling is not fully established. Thus, we tested the intra-session repeatability of the activation pattern of 10 lower limb muscles during a sub-maximal cycling exercise. Eleven triathletes participated to this study. The experimental session consisted in a reference sub-maximal cycling exercise (i.e. 150 W) performed before and after a 53-min simulated training session (mean power output=200+/-12 W). Repeatability of EMG patterns was assessed in terms of muscle activity level (i.e. RMS of the mean pedaling cycle and burst) and muscle activation timing (i.e. onset and offset of the EMG burst) for the 10 following lower limb muscles: gluteus maximus (GMax), semimembranosus (SM), Biceps femoris (BF), vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL), gastrocnemius medianus (GM) and lateralis (GL), soleus (SOL) and tibialis anterior (TA). No significant differences concerning the muscle activation level were found between test and retest for all the muscles investigated. Only VM, SOL and TA showed significant differences in muscle activation timing parameters. Whereas ICC and SEM values confirmed this weak repeatability, cross-correlation coefficients suggest a good repeatability of the activation timing parameters for all the studied muscles. Overall, the main finding of this work is the good repeatability of the EMG pattern during pedaling both in term of muscle activity level and muscle activation timing.

  2. Abdominal Adhesions

    MedlinePlus

    ... Adhesions 1 Ward BC, Panitch A. Abdominal adhesions: current and novel therapies. Journal of Surgical Research. 2011;165(1):91–111. Seek Help for ... and how to participate, visit the NIH Clinical Research Trials and You website ... Foundation for Functional Gastrointestinal Disorders 700 West Virginia ...

  3. Electromyographic activity of masticatory muscles in elderly women – a pilot study

    PubMed Central

    Gaszynska, Ewelina; Kopacz, Karolina; Fronczek-Wojciechowska, Magdalena; Padula, Gianluca; Szatko, Franciszek

    2017-01-01

    Objectives To evaluate the effect of age and chosen factors related to aging such as dentition, muscle strength, and nutrition on masticatory muscles electromyographic activity during chewing in healthy elderly women. Background With longer lifespan there is a need for maintaining optimal quality of life and health in older age. Skeletal muscle strength deteriorates in older age. This deterioration is also observed within masticatory muscles. Methods A total of 30 women, aged 68–92 years, were included in the study: 10 individuals had natural functional dentition, 10 were missing posterior teeth in the upper and lower jaw reconstructed with removable partial dentures, and 10 were edontoulous, using complete removable dentures. Surface electromyography was performed to evaluate masticatory muscles activity. Afterwards, measurement of masseter thickness with ultrasound imaging was performed, body mass index and body cell mass index were calculated, and isometric handgrip strength was measured. Results Isometric maximal voluntary contraction decreased in active masseters with increasing age and in active and passive temporalis muscles with increasing age and increasing body mass index. In active masseter, mean electromyographic activity during the sequence (time from the start of chewing till the end when the test food became ready to swallow) decreased with increasing age and during the cycle (single bite time) decreased with increasing age and increasing body mass index. In active and passive temporalis muscles, mean electromyographic activity during the sequence and the cycle decreased with increasing age, increasing body mass index, and loss of natural dentition. Individuals with natural dentition had significantly higher mean muscle activity during sequence and cycle in active temporalis muscles than those wearing full dentures and higher maximal activity during cycle in individuals with active and passive temporalis muscles than in complete denture wearers

  4. Anticipatory and Reactive Response to Falls: Muscle Synergy Activation of Forearm Muscles.

    PubMed

    Couzens, Greg; Kerr, Graham

    2015-10-01

    We investigated the surface electromyogram response of six forearm muscles to falls onto the outstretched hand. The extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, abductor pollicis longus, flexor carpi radialis and flexor carpi ulnaris muscles were sampled from eight volunteers who underwent ten self-initiated falls. All muscles initiated prior to impact. Co-contraction is the most obvious surface electromyogram feature. The predominant response is in the radial deviators. The surface electromyogram timing we recorded would appear to be a complex anticipatory response to falling modified by the effect on the forearm muscles following impact. The mitigation of the force of impact is probably more importantly through shoulder abduction and extension and elbow flexion rather than action of the forearm muscles.

  5. Shoulder muscle activity and function in common shoulder rehabilitation exercises.

    PubMed

    Escamilla, Rafael F; Yamashiro, Kyle; Paulos, Lonnie; Andrews, James R

    2009-01-01

    , posterior tilt and ER. The serratus anterior also helps stabilize the medial border and inferior angle of the scapular, preventing scapular IR (winging) and anterior tilt. If normal scapular movements are disrupted by abnormal scapular muscle firing patterns, weakness, fatigue, or injury, the shoulder complex functions less efficiency and injury risk increases. Scapula position and humeral rotation can affect injury risk during humeral elevation. Compared with scapular protraction, scapular retraction has been shown to both increase subacromial space width and enhance supraspinatus force production during humeral elevation. Moreover, scapular IR and scapular anterior tilt, both of which decrease subacromial space width and increase impingement risk, are greater when performing scaption with IR ('empty can') compared with scaption with ER ('full can'). There are several exercises in the literature that exhibit high to very high activity from the rotator cuff, deltoids and scapular muscles, such as prone horizontal abduction at 100 degrees abduction with ER, flexion and abduction with ER, 'full can' and 'empty can', D1 and D2 diagonal pattern flexion and extension, ER and IR at 0 degrees and 90 degrees abduction, standing extension from 90-0 degrees , a variety of weight-bearing upper extremity exercises, such as the push-up, standing scapular dynamic hug, forward scapular punch, and rowing type exercises. Supraspinatus activity is similar between 'empty can' and 'full can' exercises, although the 'full can' results in less risk of subacromial impingement. Infraspinatus and subscapularis activity have generally been reported to be higher in the 'full can' compared with the 'empty can', while posterior deltoid activity has been reported to be higher in the 'empty can' than the 'full can'.

  6. A Sensory Feedback Circuit Coordinates Muscle Activity in Drosophila

    PubMed Central

    Hughes, Cynthia L.; Thomas, John B.

    2007-01-01

    Drosophila larval crawling is a simple behavior that allows us to dissect the functions of specific neurons in the intact animal and explore the roles of genes in the specification of those neurons. By inhibiting subsets of neurons in the PNS, we have found that two classes of multidendritic neurons play a major role in larval crawling. The bipolar dendrites and class I mds send a feedback signal to the CNS that keeps the contraction wave progressing quickly, allowing smooth forward movement. Genetic manipulation of the sensory neurons suggests that this feedback depends on proper dendritic morphology and axon pathfinding to appropriate synaptic target areas in the CNS. Our data suggest that coordination of muscle activity in larval crawling requires feedback from neurons acting as proprioceptors, sending a “mission accomplished” signal in response to segment contraction, and resulting in rapid relaxation of the segment and propagation of the wave. PMID:17498969

  7. Motor activity affects adult skeletal muscle re-innervation acting via tyrosine kinase receptors.

    PubMed

    Sartini, Stefano; Bartolini, Fanny; Ambrogini, Patrizia; Betti, Michele; Ciuffoli, Stefano; Lattanzi, Davide; Di Palma, Michael; Cuppini, Riccardo

    2013-05-01

    Recently, muscle expression of brain-derived neurotrophic factor (BDNF) mRNA and protein under activity control has been reported. BDNF is a neurotrophin known to be involved in axon sprouting in the CNS. Hence, we set out to study the effect of chronic treadmill mid-intensity running on adult rat muscle re-innervation, and to explore the involvement of BDNF and tropomyosin-related kinase (Trk) receptors. After nerve crush, muscle re-innervation was evaluated using intracellular recordings, tension recordings, immunostaining and Western blot analyses. An enhanced muscle multiple innervation was found in running rats that was fully reversed to control values blocking Trk receptors or interrupting the running activity. An increase in muscle multiple innervation was also found in sedentary rats treated with a selective TrkB receptor agonist. The expression of TrkB receptors by intramuscular axons was demonstrated, and increased muscle expression of BDNF was found in running animals. The increase in muscle multiple innervation was consistent with the faster muscle re-innervation that we found in running animals. We conclude that, when regenerating axons contact muscle cells, muscle activity progressively increases modulating BDNF and possibly other growth factors, which in turn, acting via Trk receptors, induce axon sprouting to re-innervate skeletal muscle.

  8. Changes in electromyographic activity of trunk muscles within the sub-acute phase for individuals deemed recovered from a low back injury.

    PubMed

    Butler, Heather L; Hubley-Kozey, Cheryl L; Kozey, John W

    2013-04-01

    Evidence indicates that previous low back injury (LBI) is a strong predictor for re-injury. The purpose of this study was to examine whether neuromuscular patterns remain altered in a LBI group who were deemed recovered. Surface electromyograms from 12-abdominal and 12-back extensors sites and motion variables were recorded from 33 LBI individuals (sub-acute phase) and 54 asymptomatic controls. Pain-related variables were recorded and a clinical assessment performed for LBI participants. Subjects performed a symmetrical lift and replace task in two reaches. Pattern recognition techniques were applied to normalized activation amplitude patterns to extract key recruitment strategies. Mixed model ANOVAs tested for effects (p < 0.05). Despite similar task performance, significantly (p < 0.05) different recruitment strategies were observed for the LBI group. There were higher activation amplitudes for LBI subjects in all muscles (except posterior external oblique) and greater co-activation between abdominal and back extensor sites compared to controls. Local abdominal and back extensor sites showed altered responses to increased physical demands in the LBI group. Despite outcomes indicating recovery, the LBI group had altered neuromuscular patterns compared to asymptomatic controls supporting that residual alterations remain following recovery.

  9. Activation patterns in forearm muscles during archery shooting.

    PubMed

    Ertan, H; Kentel, B; Tümer, S T; Korkusuz, F

    2003-02-01

    A contraction and relaxation strategy with regard to forearm muscles during the release of the bowstring has often been observed during archery, but has not well been described. The purpose of this study was to analyze this strategy in archers with different levels of expertise; elite, beginner and non-archers. Electromyography (EMG) activity of the M. flexor digitorum superficialis and the M. extensor digitorum were recorded at a sampling frequency of 500 Hz, together with a pulse synchronized with the clicker snap, for twelve shots by each subject. Raw EMG records, 1-s before and after the clicker pulse, were rectified, integrated and normalized. The data was then averaged for successive shots of each subject and later for each group. All subjects including non-archers developed an active contraction of the M. extensor digitorum and a gradual relaxation of the M. flexor digitorum superficialis with the fall of the clicker. In elite archers release started about 100 ms after the fall of the clicker, whereas in beginners and non-archers release started after about 200 and 300 ms, respectively. Non-archers displayed a preparation phase involving extensive extensor activity before the release of the bowstring, which was not observed in elite and beginner archers. In conclusion, archers released the bowstring by active contraction of the forearm extensors, whereas a clear relaxation of the forearm flexors affecting the release movement was not observed.

  10. Decorin binds myostatin and modulates its activity to muscle cells

    SciTech Connect

    Miura, Takayuki; Kishioka, Yasuhiro; Wakamatsu, Jun-ichi; Hattori, Akihito; Hennebry, Alex; Berry, Carole J.; Sharma, Mridula; Kambadur, Ravi; Nishimura, Takanori . E-mail: nishi@anim.agr.hokudai.ac.jp

    2006-02-10

    Myostatin, a member of TGF-{beta} superfamily of growth factors, acts as a negative regulator of skeletal muscle mass. The mechanism whereby myostatin controls the proliferation and differentiation of myogenic cells is mostly clarified. However, the regulation of myostatin activity to myogenic cells after its secretion in the extracellular matrix (ECM) is still unknown. Decorin, a small leucine-rich proteoglycan, binds TGF-{beta} and regulates its activity in the ECM. Thus, we hypothesized that decorin could also bind to myostatin and participate in modulation of its activity to myogenic cells. In order to test the hypothesis, we investigated the interaction between myostatin and decorin by surface plasmon assay. Decorin interacted with mature myostatin in the presence of concentrations of Zn{sup 2+} greater than 10 {mu}M, but not in the absence of Zn{sup 2+}. Kinetic analysis with a 1:1 binding model resulted in dissociation constants (K {sub D}) of 2.02 x 10{sup -8} M and 9.36 x 10{sup -9} M for decorin and the core protein of decorin, respectively. Removal of the glycosaminoglycan chain by chondroitinase ABC digestion did not affect binding, suggesting that decorin could bind to myostatin with its core protein. Furthermore, we demonstrated that immobilized decorin could rescue the inhibitory effect of myostatin on myoblast proliferation in vitro. These results suggest that decorin could trap myostatin and modulate its activity to myogenic cells in the ECM.

  11. Some features of the bioelectric activity of the muscles with prolonged hypokinesia

    NASA Technical Reports Server (NTRS)

    Belaya, N. A.; Amirov, R. Z.; Shaposhnikov, Y. A.; Lebedeva, I. P.; Sologub, B. S.

    1978-01-01

    The effects of prolonged hypokinesia, brought on by confinement to bed and the attendant lack of motor activity, on the bioelectric activity of muscles are studied. Electromyographic measurements of amplitude and frequency indicators of muscular bioelectric activity were analyzed.

  12. AMP-activated protein kinase stimulates Warburg-like glycolysis and activation of satellite cells during muscle regeneration.

    PubMed

    Fu, Xing; Zhu, Mei-Jun; Dodson, Mike V; Du, Min

    2015-10-30

    Satellite cells are the major myogenic stem cells residing inside skeletal muscle and are indispensable for muscle regeneration. Satellite cells remain largely quiescent but are rapidly activated in response to muscle injury, and the derived myogenic cells then fuse to repair damaged muscle fibers or form new muscle fibers. However, mechanisms eliciting metabolic activation, an inseparable step for satellite cell activation following muscle injury, have not been defined. We found that a noncanonical Sonic Hedgehog (Shh) pathway is rapidly activated in response to muscle injury, which activates AMPK and induces a Warburg-like glycolysis in satellite cells. AMPKα1 is the dominant AMPKα isoform expressed in satellite cells, and AMPKα1 deficiency in satellite cells impairs their activation and myogenic differentiation during muscle regeneration. Drugs activating noncanonical Shh promote proliferation of satellite cells, which is abolished because of satellite cell-specific AMPKα1 knock-out. Taken together, AMPKα1 is a critical mediator linking noncanonical Shh pathway to Warburg-like glycolysis in satellite cells, which is required for satellite activation and muscle regeneration.

  13. Spectral analyses of activity of laryngeal and orofacial muscles in stutterers.

    PubMed Central

    Smith, A; Luschei, E; Denny, M; Wood, J; Hirano, M; Badylak, S

    1993-01-01

    Previous studies have reported that the disfluent speech of stutterers is often associated with tremor in orofacial muscle systems. In the present report, spectral analyses of the amplitude envelopes of laryngeal and orofacial EMGs revealed that tremor-like oscillations of EMG activity, similar to those observed in orofacial muscles, are also present in laryngeal muscles during stuttered speech. Furthermore, tremor-like oscillations in orofacial and laryngeal muscles appear to be entrained in some subjects. It is speculated that autonomic systems may provide a mechanism whereby oscillations in different muscle groups may become entrained. PMID:8270932

  14. Cerebellar brain inhibition in the target and surround muscles during voluntary tonic activation

    PubMed Central

    Panyakaew, Pattamon; Cho, Hyun Joo; Srivanitchapoom, Prachaya; Popa, Traian; Wu, Tianxia; Hallett, Mark

    2016-01-01

    Motor surround inhibition is the neural mechanism that selectively favors the contraction of target muscles and inhibits nearby muscles to prevent unwanted movements. This inhibition was previously reported at the onset of a movement, but not during a tonic contraction. Cerebellar brain inhibition (CBI) is reduced in active muscles during tonic activation; however, it has not been studied in the surround muscles. CBI was evaluated in the first dorsal interosseus (FDI) as the target muscle, and the abductor digiti minimi (ADM), flexor carpi radialis (FCR), and extensor carpi radialis (ECR) as surround muscles during rest and tonic activation of FDI in fourteen subjects. Cerebellar stimulation was performed under MRI-guided neuronavigation targeting lobule VIII of the cerebellar hemisphere. Stimulus intensities for cerebellar stimulation were based on the resting motor cortex threshold (RMT) and adjusted for the depth difference between the cerebellar and motor cortices. We used 90% to 120% of adjusted RMT as the conditioning stimulus intensity during rest. The intensity that generated the best CBI at rest in the FDI was selected for use during tonic activation. During selective tonic activation of FDI, CBI was significantly reduced only for FDI but not for the surround muscles. Unconditioned MEP sizes were increased in all muscles during FDI tonic activation compared to rest, despite background EMG activity increasing only for the FDI. Our study suggests that the cerebellum may play an important role in selective tonic finger movement by reducing its inhibition in the motor cortex only for the relevant agonist muscle. PMID:26900871

  15. Muscle Activation Patterns in Infants with Myelomeningocele Stepping on a Treadmill

    PubMed Central

    Sansom, Jennifer K.; Teulier, Caroline; Smith, Beth A.; Moerchen, Victoria; Muraszko, Karin; Ulrich, Beverly D.

    2013-01-01

    Purpose To characterize how infants with myelomeningocele (MMC) activate lower limb muscles over the first year of life, without practice, while stepping on a motorized treadmill. Methods Twelve infants with MMC were tested longitudinally at 1, 6, 12 months. Electromyography (EMG) was used to collect data from the tibialis anterior (TA), lateral gastrocnemius (LG), rectus femoris (RF), biceps femoris (BF). Results Across the first year, infants showed no EMG activity for ~50% of the stride cycle w/poor rhythmicity and timing of muscles, when activated. Single muscle activation predominated; agonist-antagonist co-activation was low. Probability of individual muscle activity across the stride decreased w/age. Conclusions Infants with MMC show high variability in timing and duration of muscle activity, few complex combinations, and very little change over time. PMID:23685739

  16. Regionalizing muscle activity causes changes to the magnitude and direction of the force from whole muscles—a modeling study

    PubMed Central

    Rahemi, Hadi; Nigam, Nilima; Wakeling, James M.

    2014-01-01

    Skeletal muscle can contain neuromuscular compartments that are spatially distinct regions that can receive relatively independent levels of activation. This study tested how the magnitude and direction of the force developed by a whole muscle would change when the muscle activity was regionalized within the muscle. A 3D finite element model of a muscle with its bounding aponeurosis was developed for the lateral gastrocnemius, and isometric contractions were simulated for a series of conditions with either a uniform activation pattern, or regionally distinct activation patterns: in all cases the mean activation from all fibers within the muscle reached 10%. The models showed emergent features of the fiber geometry that matched physiological characteristics: with fibers shortening, rotating to greater pennation, adopting curved trajectories in 3D and changes in the thickness and width of the muscle belly. Simulations were repeated for muscle with compliant, normal and stiff aponeurosis and the aponeurosis stiffness affected the changes to the fiber geometry and the resultant muscle force. Changing the regionalization of the activity resulted to changes in the magnitude, direction and center of the force vector from the whole muscle. Regionalizing the muscle activity resulted in greater muscle force than the simulation with uniform activity across the muscle belly. The study shows how the force from a muscle depends on the complex interactions between the muscle fibers and connective tissues and the region of muscle that is active. PMID:25232341

  17. A ras-dependent pathway abolishes activity of a muscle-specific enhancer upstream from the muscle creatine kinase gene.

    PubMed Central

    Sternberg, E A; Spizz, G; Perry, M E; Olson, E N

    1989-01-01

    Differentiation of skeletal myoblasts is accompanied by induction of a series of tissue-specific genes whose products are required for the specialized functions of the mature muscle fiber. The program for myogenic differentiation is subject to negative control by several peptide growth factors and by the products of mutationally activated ras oncogenes, which persistently activate intracellular cascades normally triggered by specific growth factors. Previously, we reported that induction of the muscle creatine kinase (mck) gene during myogenesis was dependent on a distal upstream enhancer that cooperated with a proximal promoter to direct high levels of expression in developing muscle cells (E. A. Sternberg, G. Spizz, W. M. Perry, D. Vizard, T. Weil, and E. N. Olson, Mol. Cell. Biol. 8:2896-2909). To investigate the mechanisms whereby ras blocks the induction of muscle-specific genes, we have examined the ability of mck 5' regulatory elements to direct expression of the linked reporter gene for chloramphenicol acetyltransferase (cat) in C2 myoblasts bearing mutant N-ras and H-ras oncogenes. In this paper we report that expression of activated ras alleles abolishes activity of the mck upstream enhancer but does not affect the activity of the mck promoter. The ability of ras to repress the expression of mck-cat fusion genes that have been transfected either transiently or stably into myoblasts suggests that ras may exert its effects on muscle-specific genes through mechanisms independent of chromatin configurations or DNA methylation. These results also suggest that ras blocks establishment of the myogenic phenotype by preventing the accumulation of regulatory factors required for transcriptional induction of muscle-specific genes. Images PMID:2651901

  18. Electrical activity from smooth muscle of the anal sphincteric area of the cat.

    PubMed Central

    Bouvier, M; Gonella, J

    1981-01-01

    1. The electrical activities of longitudinal and circular smooth muscle of the anal sphincteric area have been studied in the cat. 2. Electromyographic recordings were achieved with extracellular electrodes, in vivo on acute and chronic animals, and in vitro on the isolated organ. In addition, electrical and mechanical activities were recorded from muscle strips with the sucrose gap technique. 3. Circular muscle coat electrical activity consisted exclusively of slow variations of the membrane potential of the smooth muscle cells. Each slow potential variation was followed by a contraction. 4. The electrical activity and the concomitant contractions were tetrodotoxin resistant (10(-6) g/ml.). Both disappeared in Ca-free solution or in the presence of Mn ions (10(-3) M). 5. On circular muscle, noradrenaline (10(-8)-10(-7) g/ml. in vitro, or 0.1-0.15 mg/kg in vivo) had an excitatory effect consisting in an increase of slow potential frequency. The action of noradrenaline was antagonized by phentolamine (10(-6)-10(-5) g/ml. in vitro, or 0.2 mg/kg in vivo). 6. On circular muscle, acetylcholine (10(-8)-10(-6) g/ml.), used exclusively on muscle strips, did never produce any clear cut effect. 7. Longitudinal muscle coat electrical activity consisted of spike potentials superimposed on slow time course depolarizations which were never observed alone. Each spike was followed by a contraction. This electrical activity was tetrodotoxin resistant (10(-6) g/ml.). 8. Longitudinal muscle activity was abolished by noradrenaline (10(-6) g/ml.) and enhanced by acetylcholine (10(-8)-10(-6) g/ml.). The action of noradrenaline was antagonized by propranolol (0.2 mg/kg I.V.; 10(-6) g/ml.) and that of acetylcholine by atropine (10(-7) g/ml.). 9. Electrophysiological and pharmacological data indicate that electromechanical coupling is achieved (1) in circular muscle, through Ca dependent slow variations in membrane potential of the muscle cells and (2) in longitudinal muscle, through spike

  19. NFATc1 nucleocytoplasmic shuttling is controlled by nerve activity in skeletal muscle.

    PubMed

    Tothova, Jana; Blaauw, Bert; Pallafacchina, Giorgia; Rudolf, Rüdiger; Argentini, Carla; Reggiani, Carlo; Schiaffino, Stefano

    2006-04-15

    Calcineurin-NFAT signaling has been shown to control activity-dependent muscle gene regulation and induce a program of gene expression typical of slow oxidative muscle fibers. Following Ca2+-calmodulin stimulation, calcineurin dephosphorylates NFAT proteins and induces their translocation into the nucleus. However, NFAT nuclear translocation has never been investigated in skeletal muscle in vivo. To determine whether NFATc1 nucleocytoplasmic shuttling depends on muscle activity, we transfected fast and slow mouse muscles with plasmids coding for an NFATc1-GFP fusion protein. We found that NFATc1-GFP has a predominantly cytoplasmic localization in the fast tibialis anterior muscle but a predominantly nuclear localization in the slow soleus muscle, with a characteristic focal intranuclear distribution. Two hours of complete inactivity, induced by denervation or anaesthesia, cause NFATc1 export out of the nucleus in soleus muscle fibers, whereas electrostimulation of tibialis anterior with a low-frequency tonic impulse pattern, mimicking the firing pattern of slow motor neurons, causes NFATc1 nuclear translocation. The activity-dependent nuclear import and export of NFATc1 is a rapid event, as visualized directly in vivo by two-photon microscopy. The calcineurin inhibitor cain/cabin1 causes nuclear export of NFATc1 both in normal soleus and stimulated tibialis anterior muscle. These findings support the notion that in skeletal muscle NFATc1 is a calcineurin-dependent nerve activity sensor.

  20. Artificial selection for high activity favors mighty mini-muscles in house mice.

    PubMed

    Houle-Leroy, Philippe; Guderley, Helga; Swallow, John G; Garland, Theodore

    2003-02-01

    After 14 generations of selection for voluntary wheel running, mice from the four replicate selected lines ran, on average, twice as many revolutions per day as those from the four unselected control lines. To examine whether the selected lines followed distinct strategies in the correlated responses of the size and metabolic capacities of the hindlimb muscles, we examined mice from selected lines, housed for 8 wk in cages with access to running wheels that were either free to rotate ("wheel access" group) or locked ("sedentary"). Thirteen of twenty individuals in one selected line (line 6) and two of twenty in another (line 3) showed a marked reduction ( approximately 50%) in total hindlimb muscle mass, consistent with the previously described expression of a small-muscle phenotype. Individuals with these "mini-muscles" were not significantly smaller in total body mass compared with line-mates with normal-sized muscles. Access to free wheels did not affect the relative mass of the mini-muscles, but did result in typical mammalian training effects for mitochondrial enzyme activities. Individuals with mini-muscles showed a higher mass-specific muscle aerobic capacity as revealed by the maximal in vitro rates of citrate synthase and cytochrome c oxidase. Moreover, these mice showed the highest activities of hexokinase and carnitine palmitoyl transferase. Females with mini-muscles showed the highest levels of phosphofructokinase, and males with mini-muscles the highest levels of pyruvate dehydrogenase. As shown by total muscle enzyme contents, the increase in mass-specific aerobic capacity almost completely compensated for the reduction caused by the "loss" of muscle mass. Moreover, the mini-muscle mice exhibited the lowest contents of lactate dehydrogenase and glycogen phosphorylase. Interestingly, metabolic capacities of mini-muscled mice resemble those of muscles after endurance training. Overall, our results demonstrate that during selection for voluntary wheel

  1. Nonthermal activation of transient receptor potential vanilloid-1 channels in abdominal viscera tonically inhibits autonomic cold-defense effectors.

    PubMed

    Steiner, Alexandre A; Turek, Victoria F; Almeida, Maria C; Burmeister, Jeffrey J; Oliveira, Daniela L; Roberts, Jennifer L; Bannon, Anthony W; Norman, Mark H; Louis, Jean-Claude; Treanor, James J S; Gavva, Narender R; Romanovsky, Andrej A

    2007-07-11

    An involvement of the transient receptor potential vanilloid (TRPV) 1 channel in the regulation of body temperature (T(b)) has not been established decisively. To provide decisive evidence for such an involvement and determine its mechanisms were the aims of the present study. We synthesized a new TRPV1 antagonist, AMG0347 [(E)-N-(7-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl)-3-(2-(piperidin-1-yl)-6-(trifluoromethyl)pyridin-3-yl)acrylamide], and characterized it in vitro. We then found that this drug is the most potent TRPV1 antagonist known to increase T(b) of rats and mice and showed (by using knock-out mice) that the entire hyperthermic effect of AMG0347 is TRPV1 dependent. AMG0347-induced hyperthermia was brought about by one or both of the two major autonomic cold-defense effector mechanisms (tail-skin vasoconstriction and/or thermogenesis), but it did not involve warmth-seeking behavior. The magnitude of the hyperthermic response depended on neither T(b) nor tail-skin temperature at the time of AMG0347 administration, thus indicating that AMG0347-induced hyperthermia results from blockade of tonic TRPV1 activation by nonthermal factors. AMG0347 was no more effective in causing hyperthermia when administered into the brain (intracerebroventricularly) or spinal cord (intrathecally) than when given systemically (intravenously), which indicates a peripheral site of action. We then established that localized intra-abdominal desensitization of TRPV1 channels with intraperitoneal resiniferatoxin blocks the T(b) response to systemic AMG0347; the extent of desensitization was determined by using a comprehensive battery of functional tests. We conclude that tonic activation of TRPV1 channels in the abdominal viscera by yet unidentified nonthermal factors inhibits skin vasoconstriction and thermogenesis, thus having a suppressive effect on T(b).

  2. Changes in rabbit jaw-muscle activity parameters in response to reduced masticatory load.

    PubMed

    Grünheid, T; Brugman, P; Zentner, A; Langenbach, G E J

    2010-03-01

    Mechanical food properties influence the neuromuscular activity of jaw-closing muscles during mastication. It is, however, unknown how the activity profiles of the jaw muscles are influenced by long-term alterations in masticatory load. In order to elucidate the effect of reduced masticatory load on the daily habitual activity profiles of three functionally different jaw muscles, the electromyograms of the masseter, temporalis and digastric muscles were recorded telemetrically in 16 male rabbits between seven and 20 weeks of age. Starting at eight weeks of age the experimental animals were fed significantly softer pellets than the control animals. Daily muscle activity was quantified by the relative duration of muscle use (duty time), burst number and burst length in relation to multiple activity levels. The daily duty time and burst number of the masseter muscle were significantly lower in the experimental group than in the control group at 5% and 10% of the maximum activity during the two weeks following the change in food hardness. By contrast, altered food hardness did not significantly influence the activity characteristics of the temporalis and digastric muscles. The findings suggest that a reduction in masticatory load decreases the neuromuscular activity of the jaw-closing muscles that are primarily responsible for force generation during mastication. This decrease is most pronounced in the weeks immediately following the change in food hardness and is limited to the activity levels that reflect muscle contractions during chewing. These findings support the conclusion that the masticatory system manifests few diet-specific long-term changes in the activity profiles of jaw muscles.

  3. Fibre architecture and song activation rates of syringeal muscles are not lateralized in the European starling

    PubMed Central

    Uchida, A. M.; Meyers, R. A.; Cooper, B. G.; Goller, F.

    2010-01-01

    The songbird vocal organ, the syrinx, is composed of two sound generators, which are independently controlled by sets of two extrinsic and four intrinsic muscles. These muscles rank among the fastest vertebrate muscles, but the molecular and morphological foundations of this rapid physiological performance are unknown. Here we show that the four intrinsic muscles in the syrinx of male European starlings (Sturnus vulgaris) are composed of fast oxidative and superfast fibres. Dorsal and ventral tracheobronchialis muscles contain slightly more superfast fibres relative to the number of fast oxidative fibres than dorsal and ventral syringealis muscles. This morphological difference is not reflected in the highest, burst-like activation rate of the two muscle groups during song as assessed with electromyographic recordings. No difference in fibre type ratio was found between the corresponding muscles of the left and right sound generators. Airflow and electromyographic measurements during song indicate that maximal activation rate and speed of airflow regulation do not differ between the two sound sources. Whereas the potential for high-speed muscular control exists on both sides, the two sound generators are used differentially for modulation of acoustic parameters. These results show that large numbers of superfast fibre types are present in intrinsic syringeal muscles of a songbird, providing further confirmation of rapid contraction kinetics. However, syringeal muscles are composed of two fibre types which raises questions about the neuromuscular control of this heterogeneous muscle architecture. PMID:20228343

  4. Relationship between motor activity-related cortical potential and voluntary muscle activation.

    PubMed

    Siemionow, V; Yue, G H; Ranganathan, V K; Liu, J Z; Sahgal, V

    2000-08-01

    The purpose of this study was to investigate the relationship between EEG-derived motor activity-related cortical potential (MRCP) and voluntary muscle activation. Eight healthy volunteers participated in two experimental sessions. In one session, subjects performed isometric elbow-flexion contractions at four intensity levels [10%, 35%, 60%, and 85% maximal voluntary contraction (MVC)]. In another session, a given elbow-flexion force (35% MVC) was generated at three different rates (slow, intermediate, and fast). Thirty to 40 contractions were performed at each force level or rate. EEG signals were recorded from the scalp overlying the supplementary motor area (SMA) and contralateral sensorimotor cortex, and EMG signals were recorded from the skin surface overlying the belly of the biceps brachii and brachioradialis muscles during all contractions. In each trial, the force was used as the triggering signal for MRCP averaging. MRCP amplitude was measured from the beginning to the peak of the negative slope. The magnitude of MRCP from both EEG recording locations (sensorimotor cortex and SMA) was highly correlated with elbow-flexion force, rate of rising of force, and muscle EMG signals. These results suggest that MRCP represents cortical motor commands that scale the level of muscle activation.

  5. A continuum constitutive model for the active behaviour of skeletal muscle

    NASA Astrophysics Data System (ADS)

    Ehret, Alexander E.; Böl, Markus; Itskov, Mikhail

    2011-03-01

    In the present paper we propose a continuum constitutive model for the passive and active mechanical behaviour of skeletal muscle. Unlike most works in this field, the model is not based on an additive split between passive and active components but considers muscle tissue as one continuous biological material, which alters its properties when activated. This alteration also allows for a kinematic interpretation on the muscle fibre level and is described by a single activation-dependent model parameter. This as well as the other material parameters are obtained from standard experiments on resting and activated muscle or from microstructural information such as fibre type and twitch characteristics. In the passive state, the constitutive equations are governed by a transversely isotropic polyconvex and coercive strain-energy function. The model shows excellent agreement with experimental stress-stretch data of a passive and activated rat tibialis anterior muscle.

  6. ELECTROMYOGRAPHIC ACTIVITY OF STERNOCLEIDOMASTOID AND MASTICATORY MUSCLES IN PATIENTS WITH VESTIBULAR LESIONS

    PubMed Central

    Tartaglia, Gianluca M.; Barozzi, Stefania; Marin, Federico; Cesarani, Antonio; Ferrario, Virgilio F.

    2008-01-01

    This study evaluated the electromyographic characteristics of masticatory and neck muscles in subjects with vestibular lesions. Surface electromyography of the masseter, temporalis and sternocleidomastoid muscles was performed in 19 patients with Ménière's disease, 12 patients with an acute peripheral vestibular lesion, and 19 control subjects matched for sex and age. During maximum voluntary clenching, patients with peripheral vestibular lesions had the highest co-contraction of the sternocleidomastoid muscle (analysis of covariance, p=0.02), the control subjects had the smallest values, and the patients with Ménière's disease had intermediate values. The control subjects had larger standardized muscle activities than the other patient groups (p=0.001). In conclusion, during maximum voluntary tooth clenching, patients with vestibular alterations have both more active neck muscles, and less active masticatory muscles than normal controls. Results underline the importance of a more inclusive craniocervical assessment of patients with vestibular lesions. PMID:19082397

  7. Calcium transients in asymmetrically activated skeletal muscle fibers.

    PubMed Central

    Trube, G; Lopez, J R; Taylor, S R

    1981-01-01

    Skeletal muscle fibers of the frog Rana temporaria were held just taut and stimulated transversely by unidirectional electrical fields. We observed the reversible effects of stimulus duration (0.1-100 ms) and strength on action potentials, intracellular Ca2+ transients (monitored by aequorin), and contractile force during fixed-end contractions. Long duration stimuli (e.g., 10 ms) induced a maintained depolarization on the cathodal side of a cell and a maintained hyperpolarization on its anodal side. The hyperpolarization of the side facing the anode prevented the action potential from reaching mechanical threshold during strong stimuli. Variation of the duration or strength of a stimulus changed the luminescent response from a fiber injected with aequorin. Thus, the intracellular Ca2+ released during excitation-contraction coupling could be changed by the stimulus parameters. Prolongation of a stimulus at field strengths above 1.1 x rheobase decreased the amplitude of aequorin signals and the force of contractions. The decreases in aequorin and force signals from a given fiber paralleled one another and depended on the stimulus strength, but not on the stimulus polarity. These changes were completely reversible for stimulus strengths up to at least 4.2 x rheobase. The graded decreases in membrane depolarization, aequorin signals, and contractile force were correlated with the previously described folding of myofibrils in fibers allowed to shorten in response to the application of a long duration stimulus. The changes in aequorin signals and force suggest an absence of myofilament activation by Ca2+ in the section of the fiber closest to the anode. The results imply that injected aequorin distributes circumferentially in frog muscle with a coefficient of at least 10(-7) cm2/s, which is not remarkably different from the previously measured coefficient of 5 x 10(-8) cm2/s for its diffusion lengthwise. PMID:6976801

  8. A phenomenological model of the muscle as an active composite

    NASA Astrophysics Data System (ADS)

    Chernous, D. A.; Shil'ko, S. V.

    2008-12-01

    A phenomenological model consisting of a spring, a contractive element, and a Voigt element is proposed for describing muscle functions. To refine the description of the mechanical behavior of muscle tissue, an additional, inertial element is introduced into the model. The contractive element is characterized based on the Hill equation. A technique is elaborated for identifying the parameters of the model from the experimental time-dependent length of the muscle during its isotonic contraction. The phenomenological model is used for describing the deformation of tailor's muscle of frogs under isotonic and isometric conditions.

  9. Dexamethasone up-regulates skeletal muscle maximal Na+,K+ pump activity by muscle group specific mechanisms in humans.

    PubMed

    Nordsborg, Nikolai; Goodmann, Craig; McKenna, Michael J; Bangsbo, Jens

    2005-09-01

    Dexamethasone, a widely clinically used glucocorticoid, increases human skeletal muscle Na+,K+ pump content, but the effects on maximal Na+,K+ pump activity and subunit specific mRNA are unknown. Ten healthy male subjects ingested dexamethasone for 5 days and the effects on Na+,K+ pump content, maximal activity and subunit specific mRNA level (alpha1, alpha2, beta1, beta2, beta3) in deltoid and vastus lateralis muscle were investigated. Before treatment, maximal Na+,K+ pump activity, as well as alpha1, alpha2, beta1 and beta2 mRNA levels were higher (P < 0.05) in vastus lateralis than in deltoid. Dexamethasone treatment increased Na+,K+ pump maximal activity in vastus lateralis and deltoid by 14 +/- 7% (P < 0.05) and 18 +/- 6% (P < 0.05) as well as Na+,K+ pump content by 18 +/- 9% (P < 0.001) and 24 +/- 8% (P < 0.01), respectively. Treatment with dexamethasone resulted in a higher alpha1, alpha2, beta1 and beta2 mRNA expression in the deltoid (P < 0.05), but no effects on Na+,K+ pump mRNA were detected in vastus lateralis. In conclusion, dexamethasone treatment increased maximal Na+,K+ pump activity in both vastus lateralis and deltoid muscles. The relative importance of transcription and translation in the glucocorticoid-induced regulation of Na+,K+ pump expression seems to be muscle specific and possibly dependent on the actual training condition of the muscle, such that a high Na+,K+ pump maximal activity and mRNA level prior to treatment prevents the transcriptional response to dexamethasone, but not the increase in Na+,K+ pump content and maximal activity.

  10. Effects of training and weight support on muscle activation in Parkinson's disease.

    PubMed

    Rose, Martin H; Løkkegaard, Annemette; Sonne-Holm, Stig; Jensen, Bente R

    2013-12-01

    The aim of this study was to investigate the effect of high-intensity locomotor training on knee extensor and flexor muscle activation and adaptability to increased body-weight (BW) support during walking in patients with Parkinson's disease (PD). Thirteen male patients with idiopathic PD and eight healthy participants were included. The PD patients completed an 8-week training program on a lower-body, positive-pressure treadmill. Knee extensor and flexor muscles activation during steady treadmill walking (3 km/h) were measured before, at the mid-point, and after training. Increasing BW support decreased knee extensor muscle activation (normalization) and increased knee flexor muscle activation (abnormal) in PD patients when compared to healthy participants. Training improved flexor peak muscle activation adaptability to increased (BW) support during walking in PD patients. During walking without BW support shorter knee extensor muscle off-activation time and increased relative peak muscle activation was observed in PD patients and did not improve with 8 weeks of training. In conclusion, patients with PD walked with excessive activation of the knee extensor and flexor muscles when compared to healthy participants. Specialized locomotor training may facilitate adaptive processes related to motor control of walking in PD patients.

  11. Association of Orofacial Muscle Activity and Movement during Changes in Speech Rate and Intensity

    ERIC Educational Resources Information Center

    McClean, Michael D.; Tasko, Stephen M.

    2003-01-01

    Understanding how orofacial muscle activity and movement covary across changes in speech rate and intensity has implications for the neural control of speech production and the use of clinical procedures that manipulate speech prosody. The present study involved a correlation analysis relating average lower-lip and jaw-muscle activity to lip and…

  12. Lower physical activity is associated with fat infiltration within skeletal muscle in young girls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fat infiltration within skeletal muscle is strongly associated with obesity, type 2 diabetes mellitus, and metabolic syndrome. Lower physical activity may be a risk factor for greater fat infiltration within skeletal muscle, although whether lower physical activity is associated with fat infiltrati...

  13. Progress toward motor recovery with active neuromuscular stimulation: muscle activation pattern evidence after a stroke.

    PubMed

    Cauraugh, James H; Kim, Sangbum

    2003-03-15

    Chronic cerebrovascular accident individuals with partial paralysis in an upper extremity typically demonstrate difficulty in voluntarily controlling movement initiation. This study investigated patterns of electromyogram (EMG) activation levels while stroke subjects voluntarily initiated their impaired wrist and finger extensor muscles. Twenty subjects were randomly assigned to either a unilateral movement/stimulation group or a bilateral movement/stimulation group. Participants completed 4 days (6 h over 2 weeks) of active neuromuscular stimulation (i.e., 5 s/trial, 90 trials/day, biphasic waveform) on the wrist and finger extensors according to group assignments. The EMG activation levels were analyzed with a three-factor mixed design Motor recovery protocol x Session block x Trial block (2 x 2 x 3) ANOVA with repeated measures on the second and third factors. This robust analysis revealed higher EMG activation levels for the coupled bilateral movement/stimulation group than the unilateral movement/stimulation group. In addition, higher muscle activation levels were found for the second session block as well as trial blocks 2 and 3. Overall, these findings indicated improved motor capabilities of the impaired muscles as evidenced by the higher voluntary EMG activation levels.

  14. Activation of autophagy in human skeletal muscle is dependent on exercise intensity and AMPK activation.

    PubMed

    Schwalm, Céline; Jamart, Cécile; Benoit, Nicolas; Naslain, Damien; Prémont, Christophe; Prévet, Jérémy; Van Thienen, Ruud; Deldicque, Louise; Francaux, Marc

    2015-08-01

    In humans, nutrient deprivation and extreme endurance exercise both activate autophagy. We hypothesized that cumulating fasting and cycling exercise would potentiate activation of autophagy in skeletal muscle. Well-trained athletes were divided into control (n = 8), low-intensity (LI, n = 8), and high-intensity (HI, n = 7) exercise groups and submitted to fed and fasting sessions. Muscle biopsy samples were obtained from the vastus lateralis before, at the end, and 1 h after a 2 h LI or HI bout of exercise. Phosphorylation of ULK1(Ser317) was higher after exercise (P < 0.001). In both the fed and the fasted states, LC3bII protein level and LC3bII/I were decreased after LI and HI (P < 0.05), while p62/SQSTM1 was decreased only 1 h after HI (P < 0.05), indicating an increased autophagic flux after HI. The autophagic transcriptional program was also activated, as evidenced by the increased level of LC3b, p62/SQSTM1, GabarapL1, and Cathepsin L mRNAs observed after HI but not after LI. The increased autophagic flux after HI exercise could be due to increased AMP-activated protein kinase α (AMPKα) activity, as both AMPKα(Thr172) and ACC(Ser79) had a higher phosphorylation state after HI (P < 0.001). In summary, the most effective strategy to activate autophagy in human skeletal muscle seems to rely on exercise intensity more than diet.

  15. Activation of back and lower limb muscles during squat exercises with different trunk flexion

    PubMed Central

    Lee, Tae-Sik; Song, Min-Young; Kwon, Yu-Jeong

    2016-01-01

    [Purpose] The purpose of this study was to investigate the activation of back and lower limb muscles in subjects who were performing a squat exercise at different angles of trunk flexion. [Subjects and Methods] Twenty healthy subjects (age 21.1± 1.8 years, height 168.7 ± 8.2 cm, weight 66.1 ± 12.3 kg) volunteered. The activation of the erector spinae muscle, rectus femoris muscle, gluteus maximus muscle and biceps femoris muscle was observed while the subjects performed squat exercises with a trunk flexion of 0°, 15°, and 30°. [Results] The erector spinae muscle, gluteus maximus muscle, and biceps femoris muscle were activated more during the squat exercise with the trunk flexion at 30° than the exercise with the trunk flexion at 0°. The rectus femoris muscle showed a tendency to decrease as the truck flexion increased. [Conclusion] Squat exercise be executed while maintaining an erect trunk posture if one wishes to strengthen the quadriceps muscle while reducing the load on the lower back. PMID:28174462

  16. Superficial shoulder muscle co-activations during lifting tasks: Influence of lifting height, weight and phase.

    PubMed

    Blache, Y; Dal Maso, F; Desmoulins, L; Plamondon, A; Begon, M

    2015-04-01

    This study aimed to assess the level of co-activation of the superficial shoulder muscles during lifting movement. Boxes containing three different loads (6, 12, and 18 kg) were lifted by fourteen subjects from the waist to shoulder or eye level. The 3D kinematics and electromyograms of the three deltoids, latissimus dorsi and pectoralis major were recorded. A musculoskeletal model was used to determine direction of the moment arm of these muscles. Finally an index of muscle co-activation named the muscle focus was used to evaluate the effects of lifting height, weight lifted and phase (pulling, lifting and dropping phases) on superficial shoulder muscle coactivation. The muscle focus was lower (more co-contraction) during the dropping phase compared to the two other phases (-13%, p<0.001). This was explained by greater muscle activations and by a change in the direction of the muscle moment arm as a function of glenohumeral joint position. Consequently, the function of the shoulder superficial muscles varied with respect to the glenohumeral joint position. To increase the superficial muscle coactivation during the dropping phase may be a solution to increase glenohumeral joint stiffness.

  17. Activation of back and lower limb muscles during squat exercises with different trunk flexion.

    PubMed

    Lee, Tae-Sik; Song, Min-Young; Kwon, Yu-Jeong

    2016-12-01

    [Purpose] The purpose of this study was to investigate the activation of back and lower limb muscles in subjects who were performing a squat exercise at different angles of trunk flexion. [Subjects and Methods] Twenty healthy subjects (age 21.1± 1.8 years, height 168.7 ± 8.2 cm, weight 66.1 ± 12.3 kg) volunteered. The activation of the erector spinae muscle, rectus femoris muscle, gluteus maximus muscle and biceps femoris muscle was observed while the subjects performed squat exercises with a trunk flexion of 0°, 15°, and 30°. [Results] The erector spinae muscle, gluteus maximus muscle, and biceps femoris muscle were activated more during the squat exercise with the trunk flexion at 30° than the exercise with the trunk flexion at 0°. The rectus femoris muscle showed a tendency to decrease as the truck flexion increased. [Conclusion] Squat exercise be executed while maintaining an erect trunk posture if one wishes to strengthen the quadriceps muscle while reducing the load on the lower back.

  18. Changes in activity and structure of jaw muscles in Parkinson's disease model rats.

    PubMed

    Nakamura, S; Kawai, N; Ohnuki, Y; Saeki, Y; Korfage, J A M; Langenbach, G E J; Kitayama, T; Watanabe, M; Sano, R; Tanne, K; Tanaka, E

    2013-03-01

    Parkinson's disease (PD), a major neurological disease, is characterised by a marked loss of dopaminergic neurons in the substantia nigra. Patients with PD frequently show chewing and swallowing dysfunctions, but little is known about the characteristics of their stomatognathic functions. The purpose of this study was to evaluate the influence of PD on jaw muscle fibre and functions. PD model rats were made by means of the injection of 6-hydroxydopamine (6-OHDA) into the striatum of 8-week-old Sprague-Dawley male rats. Five weeks after the injection, a radio-telemetric device was implanted to record muscle activity continuously from the superficial masseter and anterior belly of digastric muscles. Muscle activity was recorded for 3 days and was evaluated by the total duration of muscle activity per day (duty time). After recording the muscle activities, jaw muscles were isolated for immunohistochemical and PCR analyses. In PD model rats, the following findings of the digastrics muscles verify that compared to the control group: (i) the higher duty time exceeding 5% of the peak activity level, (ii) the higher expression of the mRNA of myosin heavy chain type I, and (iii) the tendency for fast to slow fibre-type transition. With respect to the masseter muscle, there were no significant differences in all analyses. In conclusion, PD leads to the changes in the jaw behaviours, resulting in a PD-specific chewing and swallowing dysfunctions.

  19. An Active Learning Mammalian Skeletal Muscle Lab Demonstrating Contractile and Kinetic Properties of Fast- and Slow-Twitch Muscle

    ERIC Educational Resources Information Center

    Head, S. I.; Arber, M. B.

    2013-01-01

    The fact that humans possess fast and slow-twitch muscle in the ratio of approximately 50% has profound implications for designing exercise training strategies for power and endurance activities. With the growth of exercise and sport science courses, we have seen the need to develop an undergraduate student laboratory that demonstrates the basic…

  20. Temporal muscle activation assessment by ultrasound imaging during flexor withdrawal reflex and voluntary contraction.

    PubMed

    Jose, Gomez-Tames; Shuto, Nakamura; Jose, Gonzalez; Wenwei, Yu

    2013-01-01

    Activating flexor reflexes by electrical stimulation has been used as a mechanism to initiate the swing phase or to enhance it for spinal cord injured patients. However, it is necessary to know their contraction dynamics in order to artificially induce them at the right moment of a walking cycle. This requires understanding the temporal activation pattern of both surface and deep muscles simultaneously. This study aimed at developing a system to measure and analyze the temporal activation of both surface and deep muscles during voluntary contraction and flexor reflexes (also called withdrawal reflexes) using ultrasound imaging. A set of experiments were done to verify the validity of the system, while exploring the temporal pattern of muscle activation during flexor reflexes. As a result, we were able to quantify the surface and deep muscle activity by measuring the muscle thickness, pennation angle and long-axis displacement, from the ultrasound images.

  1. Changes in masticatory muscle activity according to food size in experimental human mastication.

    PubMed

    Miyawaki, S; Ohkochi, N; Kawakami, T; Sugimura, M

    2001-08-01

    The purpose of this study was to investigate the changes in masticatory muscle activity according to food size in human mastication. Sixteen subjects performed deliberate unilateral chewing of similarly cone shaped hard gummy jellies weighing 5 and 10 g. The masseter and anterior temporal muscle activity on both sides was recorded for the first 10 strokes. The normalized muscle activity during the chewing of the 10 g jelly was significantly higher than that of the 5-g jelly, and there was a considerably high significant correlationship between the muscle activity during the chewing of the 10- and 5-g jellies in each muscle on each side. The 10 g/5 g jelly ratio for the masseter muscle activity on the non-chewing side almost coincided with the theoretical energy ratio required to shear, although that of the chewing side was lower than the ratio. The 10 g/5 g jelly ratio for the temporal muscle activity on both sides almost coincided with the food height ratio. The results suggest that anterior temporal and masseter muscle activity changes according to the rate of change in the height of hard coherent food bolus and food resistance required to shear, respectively, during mastication.

  2. Quantification of Electromyographic Activity During REM Sleep in Multiple Muscles in REM Sleep Behavior Disorder

    PubMed Central

    Frauscher, Birgit; Iranzo, Alex; Högl, Birgit; Casanova-Molla, Jordi; Salamero, Manel; Gschliesser, Viola; Tolosa, Eduardo; Poewe, Werner; Santamaria, Joan

    2008-01-01

    Study Objectives: The aim of our study was to determine which muscle or combination of muscles (either axial or limb muscles, lower or upper limb muscles, or proximal or distal limb muscles) provides the highest rates of rapid eye movement (REM) sleep phasic electromyographic (EMG) activity seen in patients with REM sleep behavior disorder (RBD). Setting: Two university hospital sleep disorders centers. Participants: Seventeen patients with idiopathic RBD (n = 8) and RBD secondary to Parkinson disease (n = 9). Interventions: Not applicable. Measurements and Results: Patients underwent polysomnography, including EMG recording of 13 different muscles. Phasic EMG activity in REM sleep was quantified for each muscle separately. A mean of 1459.6 ± 613.8 three-second REM sleep mini-epochs were scored per patient. Mean percentages of phasic EMG activity were mentalis (42 ± 19), flexor digitorum superficialis (29 ± 13), extensor digitorum brevis (23 ± 12), abductor pollicis brevis (22 ± 11), sternocleidomastoid (22 ± 12), deltoid (19 ± 11), biceps brachii (19 ± 11), gastrocnemius (18 ± 9), tibialis anterior (right, 17 ± 12; left, 16 ± 10), rectus femoris (left, 11 ± 6; right, 9 ± 6), and thoraco-lumbar paraspinal muscles (6 ± 5). The mentalis muscle provided significantly higher rates of excessive phasic EMG activity than all other muscles but only detected 55% of all the mini-epochs with phasic EMG activity. Simultaneous recording of the mentalis, flexor digitorum superficialis, and extensor digitorum brevis muscles detected 82% of all mini-epochs containing phasic EMG activity. This combination provided higher rates of EMG activity than any other 3-muscle combination. Excessive phasic EMG activity was more frequent in distal than in proximal muscles, both in upper and lower limbs. Conclusion: Simultaneous recording of the mentalis, flexor digitorum superficialis, and extensor digitorum brevis muscles provided the highest rates of REM sleep phasic EMG

  3. Resistance exercise-induced fluid shifts: change in active muscle size and plasma volume

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, L. L.; Convertino, V. A.; Dudley, G. A.

    1995-01-01

    The purpose of this study was to test the hypothesis that the reduction in plasma volume (PV) induced by resistance exercise reflects fluid loss to the extravascular space and subsequently selective increase in cross-sectional area (CSA) of active but not inactive skeletal muscle. We compared changes in active and inactive muscle CSA and PV after barbell squat exercise. Magnetic resonance imaging (MRI) was used to quantify muscle involvement in exercise and to determine CSA of muscle groups or individual muscles [vasti (VS), adductor (Add), hamstring (Ham), and rectus femoris (RF)]. Muscle involvement in exercise was determined using exercise-induced contrast shift in spin-spin relaxation time (T2)-weighted MR images immediately postexercise. Alterations in muscle size were based on the mean CSA of individual slices. Hematocrit, hemoglobin, and Evans blue dye were used to estimate changes in PV. Muscle CSA and PV data were obtained preexercise and immediately postexercise and 15 and 45 min thereafter. A hierarchy of muscle involvement in exercise was found such that VS > Add > Ham > RF, with the Ham and RF showing essentially no involvement. CSA of the VS and Add muscle groups were increased 10 and 5%, respectively, immediately after exercise in each thigh with no changes in Ham and RF CSA. PV was decreased 22% immediately following exercise. The absolute loss of PV was correlated (r2 = 0.75) with absolute increase in muscle CSA immediately postexercise, supporting the notion that increased muscle size after resistance exercise reflects primarily fluid movement from the vascular space into active but not inactive muscle.

  4. Regulation of myogenesis and skeletal muscle regeneration: effects of oxygen levels on satellite cell activity.

    PubMed

    Chaillou, Thomas; Lanner, Johanna T

    2016-12-01

    Reduced oxygen (O2) levels (hypoxia) are present during embryogenesis and exposure to altitude and in pathologic conditions. During embryogenesis, myogenic progenitor cells reside in a hypoxic microenvironment, which may regulate their activity. Satellite cells are myogenic progenitor cells localized in a local environment, suggesting that the O2 level could affect their activity during muscle regeneration. In this review, we present the idea that O2 levels regulate myogenesis and muscle regeneration, we elucidate the molecular mechanisms underlying myogenesis and muscle regeneration in hypoxia and depict therapeutic strategies using changes in O2 levels to promote muscle regeneration. Severe hypoxia (≤1% O2) appears detrimental for myogenic differentiation in vitro, whereas a 3-6% O2 level could promote myogenesis. Hypoxia impairs the regenerative capacity of injured muscles. Although it remains to be explored, hypoxia may contribute to the muscle damage observed in patients with pathologies associated with hypoxia (chronic obstructive pulmonary disease, and peripheral arterial disease). Hypoxia affects satellite cell activity and myogenesis through mechanisms dependent and independent of hypoxia-inducible factor-1α. Finally, hyperbaric oxygen therapy and transplantation of hypoxia-conditioned myoblasts are beneficial procedures to enhance muscle regeneration in animals. These therapies may be clinically relevant to treatment of patients with severe muscle damage.-Chaillou, T. Lanner, J. T. Regulation of myogenesis and skeletal muscle regeneration: effects of oxygen levels on satellite cell activity.

  5. Insulin-independent, MAPK-dependent stimulation of NKCC activity in skeletal muscle.

    PubMed

    Wong, J A; Gosmanov, A R; Schneider, E G; Thomason, D B

    2001-08-01

    Na(+)-K(+)-Cl(-) cotransporter (NKCC) activity in quiescent skeletal muscle is modest. However, ex vivo stimulation of muscle for as little as 18 contractions (1 min, 0.3 Hz) dramatically increased the activity of the cotransporter, measured as the bumetanide-sensitive (86)Rb influx, in both soleus and plantaris muscles. This activation of cotransporter activity remained relatively constant for up to 10-Hz stimulation for 1 min, falling off at higher frequencies (30-Hz stimulation for 1 min). Similarly, stimulation of skeletal muscle with adrenergic receptor agonists phenylephrine, isoproterenol, or epinephrine produced a dramatic stimulation of NKCC activity. It did not appear that stimulation of NKCC activity was a reflection of increased Na(+)-K(+)-ATPase activity because insulin treatment did not stimulate NKCC activity, despite insulin's well-known stimulation of Na(+)-K(+)-ATPase activity. Stimulation of NKCC activity could be blocked by pretreatment with inhibitors of mitogen-activated protein kinase (MAPK) kinase 1/2 (MEK1/2) activity, indicating that activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) MAPKs may be required. These data indicate a regulated NKCC activity in skeletal muscle that may provide a significant pathway for potassium transport into skeletal muscle fibers.

  6. Discovery of Novel Small Molecules that Activate Satellite Cell Proliferation and Enhance Repair of Damaged Muscle.

    PubMed

    Billin, Andrew N; Bantscheff, Marcus; Drewes, Gerard; Ghidelli-Disse, Sonja; Holt, Jason A; Kramer, Henning F; McDougal, Alan J; Smalley, Terry L; Wells, Carrow I; Zuercher, William J; Henke, Brad R

    2016-02-19

    Skeletal muscle progenitor stem cells (referred to as satellite cells) represent the primary pool of stem cells in adult skeletal muscle responsible for the generation of new skeletal muscle in response to injury. Satellite cells derived from aged muscle display a significant reduction in regenerative capacity to form functional muscle. This decrease in functional recovery has been attributed to a decrease in proliferative capacity of satellite cells. Hence, agents that enhance the proliferative abilities of satellite cells may hold promise as therapies for a variety of pathological settings, including repair of injured muscle and age- or disease-associated muscle wasting. Through phenotypic screening of isolated murine satellite cells, we identified a series of 2,4-diaminopyrimidines (e.g., 2) that increased satellite cell proliferation. Importantly, compound 2 was effective in accelerating repair of damaged skeletal muscle in an in vivo mouse model of skeletal muscle injury. While these compounds were originally prepared as c-Jun N-terminal kinase 1 (JNK-1) inhibitors, structure-activity analyses indicated JNK-1 inhibition does not correlate with satellite cell activity. Screening against a broad panel of kinases did not result in identification of an obvious molecular target, so we conducted cell-based proteomics experiments in an attempt to identify the molecular target(s) responsible for the potentiation of the satellite cell proliferation. These data provide the foundation for future efforts to design improved small molecules as potential therapeutics for muscle repair and regeneration.

  7. Examination of Hand Muscle Activation and Motor Unit Indices Derived from Surface EMG in Chronic Stroke

    PubMed Central

    Li, Xiaoyan; Liu, Jie; Li, Sheng; Wang, Ying-Chih

    2014-01-01

    In this study, we used muscle and motor unit indices, derived from convenient surface electromyography (EMG) measurements, for examination of paretic muscle changes post stroke. For 12 stroke subjects, compound muscle action potential and voluntary surface EMG signals were recorded from paretic and contralateral first dorsal interosseous, abductor pollicis brevis, and abductor digiti minimi muscles. Muscle activation index (AI), motor unit number index (MUNIX), and motor unit size index (MUSIX) were then calculated for each muscle. There was a significant AI reduction for all the three muscles in paretic side compared with contralateral side, providing an evidence of muscle activation deficiency after stroke. The hand MUNIX (defined by summing the values from the three muscles) was significantly reduced in paretic side compared with contralateral side, whereas the hand MUSIX was not significantly different. Furthermore, diverse changes in MUNIX and MUSIX were observed from the three muscles. A major feature of the present examinations is the primary reliance on surface EMG, which offers practical benefits because it is noninvasive, induces minimal discomfort and can be performed quickly. PMID:24967982

  8. The CXCR4/SDF1 Axis Improves Muscle Regeneration Through MMP-10 Activity

    PubMed Central

    Bobadilla, Miriam; Sainz, Neira; Abizanda, Gloria; Orbe, Josune; Rodriguez, José Antonio; Páramo, José Antonio; Prósper, Felipe

    2014-01-01

    The CXCR4/SDF1 axis participates in various cellular processes, including cell migration, which is essential for skeletal muscle repair. Although increasing evidence has confirmed the role of CXCR4/SDF1 in embryonic muscle development, the function of this pathway during adult myogenesis remains to be fully elucidated. In addition, a role for CXCR4 signaling in muscle maintenance and repair has only recently emerged. Here, we have demonstrated that CXCR4 and stromal cell-derived factor-1 (SDF1) are up-regulated in injured muscle, suggesting their involvement in the repair process. In addition, we found that notexin-damaged muscles showed delayed muscle regeneration on treatment with CXCR4 agonist (AMD3100). Accordingly, small-interfering RNA-mediated silencing of SDF1 or CXCR4 in injured muscles impaired muscle regeneration, whereas the addition of SDF1 ligand accelerated repair. Furthermore, we identified that CXCR4/SDF1-regulated muscle repair was dependent on matrix metalloproteinase-10 (MMP-10) activity. Thus, our findings support a model in which MMP-10 activity modulates CXCR4/SDF1 signaling, which is essential for efficient skeletal muscle regeneration. PMID:24548137

  9. Impaired voluntary neuromuscular activation limits muscle power in mobility-limited older adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background. Age-related alterations of neuromuscular activation may contribute to deficits in muscle power and mobility function. This study assesses whether impaired activation of the agonist quadriceps and antagonist hamstrings, including amplitude- and velocity-dependent characteristics of activa...

  10. Impact of Functional Appliances on Muscle Activity: A Surface Electromyography Study in Children

    PubMed Central

    Woźniak, Krzysztof; Piątkowska, Dagmara; Szyszka-Sommerfeld, Liliana; Buczkowska-Radlińska, Jadwiga

    2015-01-01

    Background Electromyography (EMG) is the most objective tool for assessing changes in the electrical activity of the masticatory muscles. The purpose of the study was to evaluate the tone of the masseter and anterior temporalis muscles in growing children before and after 6 months of treatment with functional removable orthodontic appliances. Material/Methods The sample conisted of 51 patients with a mean age 10.7 years with Class II malocclusion. EMG recordings were performed by using a DAB-Bluetooth instrument (Zebris Medical GmbH, Germany). Recordings were performed in mandibular rest position, during maximum voluntary contraction (MVC), and during maximum effort. Results The results of the study indicated that the electrical activity of the muscles in each of the clinical situations was the same in the group of girls and boys. The factor that determined the activity of the muscles was their type. In mandibular rest position and in MVC, the activity of the temporalis muscles was significantly higher that that of the masseter muscels. The maximum effort test indicated a higher fatigue in masseter than in temporalis muscles. Conclusions Surface electromyography is a useful tool for monitoring muscle activity. A 6-month period of functional therapy resulted in changes in the activity of the masticatory muscles. PMID:25600247

  11. Upper Extremity Muscle Activation during Recovery of Reaching in Subjects with Post-stroke Hemiparesis

    PubMed Central

    Wagner, Joanne M.; Dromerick, Alexander W.; Sahrmann, Shirley A.; Lang, Catherine E.

    2007-01-01

    Objective To investigate upper extremity muscle activation and recovery during the first few months after stroke. Methods Subjects with hemiparesis following stroke were studied performing a reaching task at an acute time point (mean = 9 days post-stroke) and then again at a subacute time point (mean = 109 days post-stroke). We recorded kinematics and electromyographic activity of 6 upper extremity muscles. Results At the acute time point, the hemiparetic group had delayed muscle onsets, lower modulation ratios, and higher relative levels of muscle activation (%MVIC) during reaching than controls. From the acute to the subacute time points, improvements were noted in all three variables. By the subacute phase, muscle onsets were similar to controls, while modulation ratios remained lower than controls and %MVIC showed a trend toward being greater in the hemiparetic group. Changes in muscle activation were differentially related to changes in reaching performance. Conclusions Our data show that improvements in muscle timing and decreases in the relative level of volitional activation may underlie improved reaching performance in the early months after stroke. Significance Given that stroke is one of the leading causes of persistent physical disability, it is important to understand how the ability to activate muscles changes during the early phases of recovery after injury. PMID:17097340

  12. Analysis of scapular muscle EMG activity in patients with idiopathic neck pain: a systematic review.

    PubMed

    Castelein, Birgit; Cools, Ann; Bostyn, Emma; Delemarre, Jolien; Lemahieu, Trees; Cagnie, Barbara

    2015-04-01

    It is proposed that altered scapular muscle function can contribute to abnormal loading of the cervical spine. However, it is not clear if patients with idiopathic neck pain show altered activity of the scapular muscles. The aim of this paper was to systematically review the literature regarding the differences or similarities in scapular muscle activity, measured by electromyography ( = EMG), between patients with chronic idiopathic neck pain compared to pain-free controls. Case-control (neck pain/healthy) studies investigating scapular muscle EMG activity (amplitude, timing and fatigue parameters) were searched in Pubmed and Web of Science. 25 articles were included in the systematic review. During rest and activities below shoulder height, no clear differences in mean Upper Trapezius ( = UT) EMG activity exist between patients with idiopathic neck pain and a healthy control group. During overhead activities, no conclusion for scapular EMG amplitude can be drawn as a large variation of results were reported. Adaptation strategies during overhead tasks are not the same between studies. Only one study investigated timing of the scapular muscles and found a delayed onset and shorter duration of the SA during elevation in patients with idiopathic neck pain. For scapular muscle fatigue, no definite conclusions can be made as a wide variation and conflicting results are reported. Further high quality EMG research on scapular muscles (broader than the UT) is necessary to understand/draw conclusions on how scapular muscles react in the presence of idiopathic neck pain.

  13. An Analysis of Muscle Activities of Healthy Women during Pilates Exercises in a Prone Position.

    PubMed

    Kim, Bo-In; Jung, Ju-Hyeon; Shim, Jemyung; Kwon, Hae-Yeon; Kim, Haroo

    2014-01-01

    [Purpose] This study analyzed the activities of the back and hip muscles during Pilates exercises conducted in a prone position. [Subjects] The subjects were 18 healthy women volunteers who had practiced at a Pilates center for more than three months. [Methods] The subjects performed three Pilates exercises. To examine muscle activity during the exercises, 8-channel surface electromyography (Noraxon USA, Inc., Scottsdale, AZ) was used. The surface electrodes were attached to the bilateral latissimus dorsi muscle, multifidus muscle, gluteus maximus, and semitendinous muscle. Three Pilates back exercises were compared: (1) double leg kick (DLK), (2) swimming (SW), and (3) leg beat (LB). Electrical muscle activation was normalized to maximal voluntary isometric contraction. Repeated measures analysis of variance was performed to assess the differences in activation levels among the exercises. [Results] The activity of the multifidus muscle was significantly high for the SW (52.3±11.0, 50.9±9.8) and LB exercises(51.8±12.8, 48.3±13.9) and the activity of the semitendinosus muscle was higher for the LB exercise (49.2±8.7, 52.9±9.3) than for the DLK and SW exercises. [Conclusion] These results may provide basic material for when Pilates exercises are performed in a prone position and may be useful information on clinical Pilates for rehabilitation programs.

  14. Use of prediction equations to determine the accuracy of whole-body fat and fat-free mass and appendicular skeletal muscle mass measurements from a single abdominal image using computed tomography in advanced cancer patients.

    PubMed

    Kilgour, Robert D; Cardiff, Katrina; Rosenthall, Leonard; Lucar, Enriqueta; Trutschnigg, Barbara; Vigano, Antonio

    2016-01-01

    Measurements of body composition using dual-energy X-ray absorptiometry (DXA) and single abdominal images from computed tomography (CT) in advanced cancer patients (ACP) have important diagnostic and prognostic value. The question arises as to whether CT scans can serve as surrogates for DXA in terms of whole-body fat-free mass (FFM), whole-body fat mass (FM), and appendicular skeletal muscle (ASM) mass. Predictive equations to estimate body composition for ACP from CT images have been proposed (Mourtzakis et al. 2008; Appl. Physiol. Nutr. Metabol. 33(5): 997-1006); however, these equations have yet to be validated in an independent cohort of ACP. Thus, this study evaluated the accuracy of these equations in estimating FFM, FM, and ASM mass using CT images at the level of the third lumbar vertebrae and compared these values with DXA measurements. FFM, FM, and ASM mass were estimated from the prediction equations proposed by Mourtzakis and colleagues (2008) using single abdominal CT images from 43 ACP and were compared with whole-body DXA scans using Spearman correlations and Bland-Altman analyses. Despite a moderate to high correlation between the actual (DXA) and predicted (CT) values for FM (rho = 0.93; p ≤ 0.001), FFM (rho = 0.78; p ≤ 0.001), and ASM mass (rho = 0.70; p ≤ 0.001), Bland-Altman analyses revealed large range-of-agreement differences between the 2 methods (29.39 kg for FFM, 15.47 kg for FM, and 3.99 kg for ASM mass). Based on the magnitude of these differences, we concluded that prediction equations using single abdominal CT images have poor accuracy, cannot be considered as surrogates for DXA, and may have limited clinical utility.

  15. Simulation of active skeletal muscle tissue with a transversely isotropic viscohyperelastic continuum material model.

    PubMed

    Khodaei, Hamid; Mostofizadeh, Salar; Brolin, Karin; Johansson, Håkan; Osth, Jonas

    2013-05-01

    Human body models with biofidelic kinematics in vehicle pre-crash and crash simulations require a constitutive model of muscle tissue with both passive and active properties. Therefore, a transversely isotropic viscohyperelastic continuum material model with element-local fiber definition and activation capability is suggested for use with explicit finite element codes. Simulations of experiments with New Zealand rabbit's tibialis anterior muscle at three different strain rates were performed. Three different active force-length relations were used, where a robust performance of the material model was observed. The results were compared with the experimental data and the simulation results from a previous study, where the muscle tissue was modeled with a combination of discrete and continuum elements. The proposed material model compared favorably, and integrating the active properties of the muscle into a continuum material model opens for applications with complex muscle geometries.

  16. The correlation between muscle activity of the quadriceps and balance and gait in stroke patients

    PubMed Central

    Yang, Dae Jung; Park, Seung Kyu; Uhm, Yo Han; Park, Sam Heon; Chun, Dong Whan; Kim, Je Ho

    2016-01-01

    [Purpose] The purpose of this study was to examine the correlation between quadriceps muscle activity and balance and gait in stroke patients. [Subjects and Methods] Fifty-five stroke patients (30 males 25 females; mean age 58.7 years; stroke duration 4.82 months; Korean mini-mental state examination score 26.4) participated in this study. MP100 surface electromyography, BioRescue, and LUKOtronic were used to measure the quadriceps muscle activity, balance, and gait, respectively. [Results] There was a significant correlation between quadriceps muscle activity (vastus lateralis % reference voluntary contraction, vastus medialis % reference voluntary contraction) and balance (limits of stability) and gait (gait velocity) but there was none between vastus lateralis % reference voluntary contraction, vastus medialis % reference voluntary contraction. [Conclusion] An increase in quadriceps muscle activity will improve balance and gait ability. To improve function in stroke patients, training is needed to strengthen the quadriceps muscles. PMID:27630416

  17. Evaluation of document location during computer use in terms of neck muscle activity and neck movement.

    PubMed

    Goostrey, Sonya; Treleaven, Julia; Johnston, Venerina

    2014-05-01

    This study evaluated the impact on neck movement and muscle activity of placing documents in three commonly used locations: in-line, flat desktop left of the keyboard and laterally placed level with the computer screen. Neck excursion during three standard head movements between the computer monitor and each document location and neck extensor and upper trapezius muscle activity during a 5 min typing task for each of the document locations was measured in 20 healthy participants. Results indicated that muscle activity and neck flexion were least when documents were placed laterally suggesting it may be the optimal location. The desktop option produced both the greatest neck movement and muscle activity in all muscle groups. The in-line document location required significantly more neck flexion but less lateral flexion and rotation than the laterally placed document. Evaluation of other holders is needed to guide decision making for this commonly used office equipment.

  18. Multiparity causes uncoordinated activity of pelvic- and perineal-striated muscles and urodynamic changes in rabbits.

    PubMed

    Martínez-Gómez, Margarita; Mendoza-Martínez, Germán; Corona-Quintanilla, Dora Luz; Fajardo, Víctor; Rodríguez-Antolín, Jorge; Castelán, Francisco

    2011-12-01

    Temporal and coordinated activation of pelvic- (pubococcygeous) and perineal- (bulbospongiosus and ischiocavernosus) striated muscles occurs during micturition in female rabbits. We have hypothesized that the coordinated activation of pelvic and perineal muscles is modified during the micturition of young multiparous rabbits. Young virgin and multiparous female chinchilla rabbits were used to simultaneously record cystometrograms and electromyograms of the pubococcygeous, ischocavernosus, and bulbospongiosus muscles. Bladder function was assessed using standard urodynamic variables. The temporal coordination of pelvic- and perineal-striated muscle activity was changed in multiparous rabbits. The cystometrogram recordings were different than those obtained from virgin rabbits, as seen in alterations of the threshold volume, the residual volume, the voiding duration, and the maximum pressure. In rabbits, we find that multiparity causes uncoordinated activity of pubococcygeous, ischiocavernosus, and bulbospongiosus muscles and modifies the urodynamics.

  19. Expiratory muscle control during vomiting - Role of brain stem expiratory neurons

    NASA Technical Reports Server (NTRS)

    Miller, A. D.; Tan, L. K.

    1987-01-01

    The neural mechanisms controlling the muscles involved during vomiting were examined using decerebrated cats. In one experiment, the activity of the ventral respiratory group (VRG) expiratory (E) neurons was recorded during induced 'fictive vomiting' (i.e., a series of bursts of coactivation of abdominal and phrenic nerves that would be expected to produce expulsion in unparalyzed animals) and vomiting. In a second, abdominal muscle electromyographic and nerve activity were compared before and after sectioning the axons of descending VRG E neurons as they cross the midline between C1 and the obex (the procedure that is known to abolish expiratory modulation of internal intercostal muscle activity). The results of the study indicate that the abdominal muscles are controlled differently during respiration and vomiting.

  20. Glucocorticoids activate the ATP-ubiquitin-dependent proteolytic system in skeletal muscle during fasting

    NASA Technical Reports Server (NTRS)

    Wing, S. S.; Goldberg, A. L.; Goldberger, A. L. (Principal Investigator)

    1993-01-01

    Glucocorticoids are essential for the increase in protein breakdown in skeletal muscle normally seen during fasting. To determine which proteolytic pathway(s) are activated upon fasting, leg muscles from fed and fasted normal rats were incubated under conditions that block or activate different proteolytic systems. After food deprivation (1 day), the nonlysosomal ATP-dependent process increased by 250%, as shown in experiments involving depletion of muscle ATP. Also, the maximal capacity of the lysosomal process increased 60-100%, but no changes occurred in the Ca(2+)-dependent or the residual energy-independent proteolytic processes. In muscles from fasted normal and adrenalectomized (ADX) rats, the protein breakdown sensitive to inhibitors of the lysosomal or Ca(2+)-dependent pathways did not differ. However, the ATP-dependent process was 30% slower in muscles from fasted ADX rats. Administering dexamethasone to these animals or incubating their muscles with dexamethasone reversed this defect. During fasting, when the ATP-dependent process rises, muscles show a two- to threefold increase in levels of ubiquitin (Ub) mRNA. However, muscles of ADX animals failed to show this response. Injecting dexamethasone into the fasted ADX animals increased muscle Ub mRNA within 6 h. Thus glucocorticoids activate the ATP-Ub-dependent proteolytic pathway in fasting apparently by enhancing the expression of components of this system such as Ub.

  1. Might as Well Jump: Sound Affects Muscle Activation in Skateboarding

    PubMed Central

    Cesari, Paola; Camponogara, Ivan; Papetti, Stefano; Rocchesso, Davide; Fontana, Federico

    2014-01-01

    The aim of the study is to reveal the role of sound in action anticipation and performance, and to test whether the level of precision in action planning and execution is related to the level of sensorimotor skills and experience that listeners possess about a specific action. Individuals ranging from 18 to 75 years of age - some of them without any skills in skateboarding and others experts in this sport - were compared in their ability to anticipate and simulate a skateboarding jump by listening to the sound it produces. Only skaters were able to modulate the forces underfoot and to apply muscle synergies that closely resembled the ones that a skater would use if actually jumping on a skateboard. More importantly we showed that only skaters were able to plan the action by activating anticipatory postural adjustments about 200 ms after the jump event. We conclude that expert patterns are guided by auditory events that trigger proper anticipations of the corresponding patterns of movements. PMID:24619134

  2. Arterial Myogenic Activation through Smooth Muscle Filamin A.

    PubMed

    Retailleau, Kevin; Arhatte, Malika; Demolombe, Sophie; Peyronnet, Rémi; Baudrie, Véronique; Jodar, Martine; Bourreau, Jennifer; Henrion, Daniel; Offermanns, Stefan; Nakamura, Fumihiko; Feng, Yuanyi; Patel, Amanda; Duprat, Fabrice; Honoré, Eric

    2016-03-08

    Mutations in the filamin A (FlnA) gene are frequently associated with severe arterial abnormalities, although the physiological role for this cytoskeletal element remains poorly understood in vascular cells. We used a conditional mouse model to selectively delete FlnA in smooth muscle (sm) cells at the adult stage, thus avoiding the developmental effects of the knockout. Basal blood pressure was significantly reduced in conscious smFlnA knockout mice. Remarkably, pressure-dependent tone of the resistance caudal artery was lost, whereas reactivity to vasoconstrictors was preserved. Impairment of the myogenic behavior was correlated with a lack of calcium influx in arterial myocytes upon an increase in intraluminal pressure. Notably, the stretch activation of CaV1.2 was blunted in the absence of smFlnA. In conclusion, FlnA is a critical upstream element of the signaling cascade underlying the myogenic tone. These findings allow a better understanding of the molecular basis of arterial autoregulation and associated disease states.

  3. Regulation of muscle sympathetic nerve activity after bed rest deconditioning

    NASA Technical Reports Server (NTRS)

    Pawelczyk, J. A.; Zuckerman, J. H.; Blomqvist, C. G.; Levine, B. D.

    2001-01-01

    Cardiovascular deconditioning reduces orthostatic tolerance. To determine whether changes in autonomic function might produce this effect, we developed stimulus-response curves relating limb vascular resistance, muscle sympathetic nerve activity (MSNA), and pulmonary capillary wedge pressure (PCWP) with seven subjects before and after 18 days of -6 degrees head-down bed rest. Both lower body negative pressure (LBNP; -15 and -30 mmHg) and rapid saline infusion (15 and 30 ml/kg body wt) were used to produce a wide variation in PCWP. Orthostatic tolerance was assessed with graded LBNP to presyncope. Bed rest reduced LBNP tolerance from 23.9 +/- 2.1 to 21.2 +/- 1.5 min, respectively (means +/- SE, P = 0.02). The MSNA-PCWP relationship was unchanged after bed rest, though at any stage of the LBNP protocol PCWP was lower, and MSNA was greater. Thus bed rest deconditioning produced hypovolemia, causing a shift in operating point on the stimulus-response curve. The relationship between limb vascular resistance and MSNA was not significantly altered after bed rest. We conclude that bed rest deconditioning does not alter reflex control of MSNA, but may produce orthostatic intolerance through a combination of hypovolemia and cardiac atrophy.

  4. Evaluation of Muscle Activities in Human Forearms under Exercises by Diffuse Optical Tomography

    NASA Astrophysics Data System (ADS)

    Tanikawa, Yukari; Gao, Feng; Miyakawa, Michio; Kiryu, Toru; Kizuka, Tomohiro; Endo, Yasuomi; Okawa, Shinpei; Yamada, Yukio

    During the forearm exercise, it is generally understood that the inner muscles work for the task, and the outer muscles work to fix the joints for the efficient work of the inner muscles. For evaluation of the exercise, quantitative measurement of inner muscle activities is necessary. Electromyograph (EMG) and oxygen monitoring using continuous-wave near-infrared spectroscopy (CW-NIRS) have been used for the evaluation because both of them are the modalities of safe, portable and noninvasive measurements of muscle activities. However, these modalities can show the qualitative changes in the muscle activities in the vicinity of the skin surface. Time-resolved diffuse optical tomography (TR-DOT) can quantitatively provide tomographic images of the changes in the oxygenation state of the whole muscles. In vivo experiments of TR-DOT were performed for human forearms under handgrip exercises, and DOT images of the changes in the oxygenation state of the forearms were reconstructed using the algorithm based on the modified generalized pulsed spectrum technique. The DOT images are compared with the MR-images, and it is shown that the activities of the inner muscles of the forearms were active during the handgrip excises.

  5. The variability of co-activation pattern of antagonist muscles in human infant crawling.

    PubMed

    Xiong, Qi L; Wu, Xiao Y; Nong Xiao; Zeng, Si Y; Zheng, Xiao L; Di Wu; Hou, Wen S

    2016-08-01

    Infant crawling is part of normal human gross motor development, and a 4-beat gait that involves rhythmical flexion and extension of limbs and the underlying muscle co-activation of antagonist muscle around the joint. However, detection the co-activation pattern of antagonist muscle are sparse due to the general difficulty of measuring locomotion in human infants. In this paper, sEMG of antagonist muscles and the corresponding kinematics data of limbs were collected when infants were crawling on hands and knees at their self-selected speed. The infant's gross motor developmental status was assessed by the global Gross Motor Function Measure Scale (GMFM-88) as well. The method based on EMG-EMG plots was used to quantify the variability of co-activation pattern of antagonist muscle. After that, we observed that antagonist muscles of upper limb (triceps brachii and biceps brachii) showed less variability of co-activation pattern of muscles than lower limb(quadriceps femoris and hamstrings) during crawling, and this variability was also varied in different crawling phases (stance and swing). Furthermore, we found some varied behaviors in the co-activation patterns of antagonist muscles when gross motor developmental level increased. The preliminary work suggests that such adaptive changes may be related to the adjustment of neuromuscular in the early stage of gross motor development.

  6. Influence of 14-day hind limb unloading on isolated muscle spindle activity in rats.

    PubMed

    Zhao, Xue Hong; Fan, Xiao Li; Song, Xin Ai; Wu, Su Di; Ren, Jun Chan; Chen, Ming Xia

    2010-09-01

    During hind limb unloading (HU), the soleus is often in a shortened position and the natural physiological stimulus of muscle spindles is altered, such that muscle spindle activity also changes. Using isolated spindle conditions, the present study investigates the electrophysiological activity and ultrastructure of muscle spindles following HU. Results show that muscle spindle discharges fall into either of two main patterns, single spikes or spike clusters in shortened positions, with a steady frequency of 18-38 spikes/s (mean 29.08 +/- 2.45) in an extended position. Following 14-day HU, afferent discharge activity was significantly altered in soleus muscle spindles. Duration of individual spikes was significantly prolonged, from 0.54 +/- 0.05 ms for control rats to 1.53 +/- 0.25 ms for rats in the HU group. In a shortened position, regular rhythm afferent discharges were obviously depressed, and the majority of muscle spindles became silent, while in an extended position, the discharges remained continuous but with decreased frequency. Results also show that the ultrastructure of muscle spindles experience degenerative changes during HU. Altered muscle spindle afference could possibly modify the activity of motor neurons and further affect the activity of extrafusal fibers.

  7. Lower Extremity Muscle Activation and Kinematics of Catchers When Throwing Using Various Squatting and Throwing Postures

    PubMed Central

    Peng, Yi-Chien; Lo, Kuo-Cheng; Wang, Lin-Hwa

    2015-01-01

    This study investigated the differences in joint motions and muscle activities of the lower extremities involved in various squatting postures. The motion capture system with thirty-one reflective markers attached on participants was used for motion data collection. The electromyography system was applied over the quadriceps, biceps femoris, tibialis anterior, and gastrocnemius muscles of the pivot and stride leg. The joint extension and flexion in wide squatting are greater than in general squatting (p = 0.005). Knee joint extension and flexion in general squatting are significantly greater than in wide squatting (p = 0.001). The adduction and abduction of the hip joint in stride passing are significantly greater than in step squatting (p = 0.000). Furthermore, the adduction and abduction of the knee joint in stride passing are also significantly greater than in step squatting (p = 0.000). When stride passing is performed, the muscle activation of the hamstring of the pivot foot in general squatting is significantly greater than in wide squatting (p < 0.05), and this difference continues to the stride period. Most catchers use a general or wide squatting width, exclusive of a narrow one. Therefore, the training design for strengthening the lower extremity muscles should consider the appropriateness of the common squat width to enhance squat-up performance. For lower limb muscle activation, wide squatting requires more active gastrocnemius and tibialis anterior muscles. Baseball players should extend the knee angle of the pivot foot before catching the ball. Key points Common squatting width can enhance squat-up performance through strengthening lower body muscle. Wide squatting width might improve lower body muscle activation, leading to more effective communication between the brain and the muscle group. The benefit might be improved coordination of lower body muscle. Common and wide squatting width might be cycled through training to enhance the strengthen and

  8. S1P lyase in skeletal muscle regeneration and satellite cell activation: exposing the hidden lyase.

    PubMed

    Saba, Julie D; de la Garza-Rodea, Anabel S

    2013-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid whose actions are essential for many physiological processes including angiogenesis, lymphocyte trafficking and development. In addition, S1P serves as a muscle trophic factor that enables efficient muscle regeneration. This is due in part to S1P's ability to activate quiescent muscle stem cells called satellite cells (SCs) that are needed for muscle repair. However, the molecular mechanism by which S1P activates SCs has not been well understood. Further, strategies for harnessing S1P signaling to recruit SCs for therapeutic benefit have been lacking. S1P is irreversibly catabolized by S1P lyase (SPL), a highly conserved enzyme that catalyzes the cleavage of S1P at carbon bond C(2-3), resulting in formation of hexadecenal and ethanolamine-phosphate. SPL enhances apoptosis through substrate- and product-dependent events, thereby regulating cellular responses to chemotherapy, radiation and ischemia. SPL is undetectable in resting murine skeletal muscle. However, we recently found that SPL is dynamically upregulated in skeletal muscle after injury. SPL upregulation occurred in the context of a tightly orchestrated genetic program that resulted in a transient S1P signal in response to muscle injury. S1P activated quiescent SCs via a sphingosine-1-phosphate receptor 2 (S1P2)/signal transducer and activator of transcription 3 (STAT3)-dependent pathway, thereby facilitating skeletal muscle regeneration. Mdx mice, which serve as a model for muscular dystrophy (MD), exhibited skeletal muscle SPL upregulation and S1P deficiency. Pharmacological SPL inhibition raised skeletal muscle S1P levels, enhanced SC recruitment and improved mdx skeletal muscle regeneration. These findings reveal how S1P can activate SCs and indicate that SPL suppression may provide a therapeutic strategy for myopathies. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.

  9. Passive stretch reduces calpain activity through nitric oxide pathway in unloaded soleus muscles.

    PubMed

    Xu, Peng-Tao; Li, Quan; Sheng, Juan-Juan; Chang, Hui; Song, Zhen; Yu, Zhi-Bin

    2012-08-01

    Unloading in spaceflight or long-term bed rest induces to pronounced atrophy of anti-gravity skeletal muscles. Passive stretch partially resists unloading-induced atrophy of skeletal muscle, but the mechanism remains elusive. The aims of this study were to investigate the hypotheses that stretch tension might increase protein level of neuronal nitric oxide synthase (nNOS) in unloaded skeletal muscle, and then nNOS-derived NO alleviated atrophy of skeletal muscle by inhibiting calpain activity. The tail-suspended rats were used to unload rat hindlimbs for 2 weeks, at the same time, left soleus muscle was stretched by applying a plaster cast to fix the ankle at 35° dorsiflexion. Stretch partially resisted atrophy and inhibited the decreased protein level and activity of nNOS in unloaded soleus muscles. Unloading increased frequency of calcium sparks and elevated intracellular resting and caffeine-induced Ca(2+) concentration ([Ca(2+)]i) in unloaded soleus muscle fibers. Stretch reduced frequency of calcium sparks and restored intracellular resting and caffeine-induced Ca(2+) concentration to control levels in unloaded soleus muscle fibers. The increased protein level and activity of calpain as well as the higher degradation of desmin induced by unloading were inhibited by stretch in soleus muscles. In conclusion, these results suggest that stretch can preserve the stability of sarcoplasmic reticulum Ca(2+) release channels which prevents the elevated [Ca(2+)]i by means of keeping nNOS activity, and then the enhanced protein level and activity of calpain return to control levels in unloaded soleus muscles. Therefore, stretch can resist in part atrophy of unloaded soleus muscles.

  10. Activation heat, activation metabolism and tension-related heat in frog semitendinosus muscles

    PubMed Central

    Homsher, E.; Mommaerts, W. F. H. M.; Ricchiuti, N. V.; Wallner, A.

    1972-01-01

    1. Frog semitendinosus muscles were stretched to various lengths beyond the rest length (l0) and their initial heat and isometric tension production were measured. 2. As the overlap between the thick and thin filaments is reduced, the initial twitch heat and tension decline in a linear manner. At a point at which the twitch tension approaches zero, the initial heat is 30% of that seen at l0. It is concluded that this heat is the activation heat and reflects the energetics of calcium release and reaccumulation. The initial heat at shorter sarcomere lengths appears to be the sum of the activation heat plus a heat production associated with the interaction of the thick and thin filaments. 3. A similar relationship between heat and tension production is seen in tetanic contractions. 4. The time course of activation heat production in a twitch can be resolved into two phases: a temperature insensitive (Q10 < 1·3) `fast' phase (with a time constant of 45 msec) and a temperature sensitive (Q10 = 2·8) `slow' phase (with a time constant of 330 msec at 0° C). 5. Measurements of the creatine phosphate (PC) hydrolysis by muscles contracting isometrically at various muscle lengths at and beyond l0, indicate an enthalpy change of -11·2 kcal/mole PC hydrolysed. The enthalpy change for the ATP hydrolysis by muscles stretched so that little or no tension was produced with stimulation was -9·9 kcal/mole ATP hydrolysed. It is concluded that the net activation heat is produced by the hydrolysis of PC or ATP. PMID:4536938

  11. The effect of lumbar posture on abdominal muscle thickness during an isometric leg task in people with and without non-specific low back pain.

    PubMed

    Pinto, Rafael Zambelli; Ferreira, Paulo Henrique; Franco, Marcia Rodrigues; Ferreira, Mariana Calais; Ferreira, Manuela Loureiro; Teixeira-Salmela, Luci Fuscaldi; Oliveira, Vinicius C; Maher, Christopher

    2011-12-01

    This study investigated the effect of lumbar posture on function of transversus abdominis (TrA) and obliquus internus (OI) in people with and without non-specific low back pain (LBP) during a lower limb task. Rehabilitative ultrasound was used to measure thickness change of TrA and OI during a lower limb task that challenged the stability of the spine. Measures were taken in supine in neutral and flexed lumbar postures in 30 patients and 30 healthy subjects. Data were analysed using a two-way (groups, postures) ANOVA. Our results showed that lumbar posture influenced percent thickness change of the TRA muscle but not for OI. An interaction between group and posture was found for TrA thickness change (F(1,56) = 6.818, p = 0.012). For this muscle, only healthy participants showed greater thickness change with neutral posture compared to flexed (mean difference = 6.2%; 95% CI: 3.1-9.3%; p < 0.001). Comparisons between groups for both muscles were not significant. Neutral lumbar posture can facilitate an increase in thickness of the TrA muscle while performing a leg task, however this effect was not observed for this muscle in patients with LBP. No significant difference in TrA and OI thickness change between people with and without non-specific LBP was found.

  12. The activation patterns of embryonic chick motoneurones projecting to inappropriate muscles.

    PubMed Central

    Landmesser, L T; O'Donovan, M J

    1984-01-01

    Chick lumbosacral motoneurones were caused to innervate foreign muscles by surgically rotating or shifting the limb bud about the anterior-posterior axis in stage 17-18 embryos. The activation pattern of such wrongly projecting motoneurones was assessed at stages 35-38 by recording electromyographic activity from muscles in an isolated spinal cord/hind limb preparation. Muscle activity was classed as flexor- or extensor-like according to the characteristics of the patterned sequence of bursts elicited by a single shock to the thoracic cord. Wrongly projecting motoneurones did not have their activation pattern altered to one appropriate for the muscle innervated; therefore in some cases a particular muscle was activated with a pattern similar to its original one, and in other cases in an opposite manner. Mixed flexor-extensor-like activation of a single muscle was, however, rare. The identity of motoneurones projecting to a muscle was determined by their cord location following retrograde labelling with horseradish peroxidase. This allowed us to conclude that motoneurones could develop their normal pattern of activation even when projecting to foreign muscles. It is concluded that the cord circuits (presumably composed of local interneurones responsible for the activation of motoneurones in the isolated cord preparation are not altered by retrograde influences from the muscle. Wrongly projecting motoneurones, which were maintained throughout the normal cell death period, were activated during spontaneous embryonic movements, and in many cases were found to have a behaviourally inappropriate activation pattern. These observations are discussed in relation to proposed mechanisms by which developmental errors in connectivity are corrected. Images Fig. 1 PMID:6707957

  13. The activation patterns of embryonic chick motoneurones projecting to inappropriate muscles.

    PubMed

    Landmesser, L T; O'Donovan, M J

    1984-02-01

    Chick lumbosacral motoneurones were caused to innervate foreign muscles by surgically rotating or shifting the limb bud about the anterior-posterior axis in stage 17-18 embryos. The activation pattern of such wrongly projecting motoneurones was assessed at stages 35-38 by recording electromyographic activity from muscles in an isolated spinal cord/hind limb preparation. Muscle activity was classed as flexor- or extensor-like according to the characteristics of the patterned sequence of bursts elicited by a single shock to the thoracic cord. Wrongly projecting motoneurones did not have their activation pattern altered to one appropriate for the muscle innervated; therefore in some cases a particular muscle was activated with a pattern similar to its original one, and in other cases in an opposite manner. Mixed flexor-extensor-like activation of a single muscle was, however, rare. The identity of motoneurones projecting to a muscle was determined by their cord location following retrograde labelling with horseradish peroxidase. This allowed us to conclude that motoneurones could develop their normal pattern of activation even when projecting to foreign muscles. It is concluded that the cord circuits (presumably composed of local interneurones responsible for the activation of motoneurones in the isolated cord preparation are not altered by retrograde influences from the muscle. Wrongly projecting motoneurones, which were maintained throughout the normal cell death period, were activated during spontaneous embryonic movements, and in many cases were found to have a behaviourally inappropriate activation pattern. These observations are discussed in relation to proposed mechanisms by which developmental errors in connectivity are corrected.

  14. Fate of gamma-interferon-activated killer blood monocytes adoptively transferred into the abdominal cavity of patients with peritoneal carcinomatosis

    SciTech Connect

    Stevenson, H.C.; Keenan, A.M.; Woodhouse, C.; Ottow, R.T.; Miller, P.; Steller, E.P.; Foon, K.A.; Abrams, P.G.; Beman, J.; Larson, S.M.

    1987-11-15

    Five patients with colorectal cancer widely metastatic to peritoneal surfaces have been treated i.p. with infusions of autologous blood monocytes made cytotoxic by in vitro incubation with human gamma-interferon. The monocytes were purified by a combination of cytapheresis and counter-current centrifugal elutriation procedures; each week approximately 350 million activated monocytes were given to patients as adoptive immunotherapy by a single i.p. instillation. On the eighth cycle of treatment the trafficking of i.p. infused blood monocytes was studied in two patients by prelabeling the cells with /sup 111/In. These activated cells became distributed widely within the peritoneal cavity. Two and 5 days after infusion their position within the peritoneum had not changed. When peritoneal specimens were obtained 36 h after /sup 111/In-labeled monocyte infusion, labeled monocytes were demonstrated to be associated with the serosal surfaces by autoradiographic analysis. Scintiscanning structures outside the abdominal cavity revealed that /sup 111/In-labeled monocytes infused i.p. did not traffic to other organs during the 5 days of the study. We conclude that i.p. adoptive transfer of autologous killer blood monocytes is an effective way of delivering these cytotoxic cells to sites of tumor burden on peritoneal surfaces in these cancer patients.

  15. Activation of TRPV1 and TRPA1 leads to muscle nociception and mechanical hyperalgesia.

    PubMed

    Ro, Jin Y; Lee, Jong-Seok; Zhang, Youping

    2009-08-01

    The involvement of TRPV1 and TRPA1 in mediating craniofacial muscle nociception and mechanical hyperalgesia was investigated in male Sprague-Dawley rats. First, we confirmed the expression of TRPV1 in masseter afferents in rat trigeminal ganglia (TG), and provided new data that TRPA1 is also expressed in primary afferents innervating masticatory muscles in double-labeling immunohistochemistry experiments. We then examined whether the activation of each TRP channel in the masseter muscle evokes acute nocifensive responses and leads to the development of masseter hypersensitivity to mechanical stimulation using the behavioral models that have been specifically designed and validated for the craniofacial system. Intramuscular injections with specific agonists for TRPV1 and TRPA1, capsaicin and mustard oil (MO), respectively, produced immediate nocifensive hindpaw responses followed by prolonged mechanical hyperalgesia in a concentration-dependent manner. Pretreatment of the muscle with a TRPV1 antagonist, capsazepine, effectively attenuated the capsaicin-induced muscle nociception and mechanical hyperalgesia. Similarly, pretreatment of the muscle with a selective TRPA1 antagonist, AP18, significantly blocked the MO-induced muscle nociception and mechanical hyperalgesia. We confirmed these data with another set of selective antagonist for TRPV1 and TRPA1, AMG9810 and HC030031, respectively. Collectively, these results provide compelling evidence that TRPV1 and TRPA1 can functionally contribute to muscle nociception and hyperalgesia, and suggest that TRP channels expressed in muscle afferents can engage in the development of pathologic muscle pain conditions.

  16. Skeletal muscle adiposity is associated with physical activity, exercise capacity and fibre shift in COPD

    PubMed Central

    Maddocks, Matthew; Shrikrishna, Dinesh; Vitoriano, Simone; Natanek, Samantha A.; Tanner, Rebecca J.; Hart, Nicholas; Kemp, Paul R.; Moxham, John; Polkey, Michael I.; Hopkinson, Nicholas S.

    2014-01-01

    Quadriceps muscle phenotype varies widely between patients with chronic obstructive pulmonary disease (COPD) and cannot be determined without muscle biopsy. We hypothesised that measures of skeletal muscle adiposity could provide noninvasive biomarkers of muscle quality in this population. In 101 patients and 10 age-matched healthy controls, mid-thigh cross-sectional area, percentage intramuscular fat and skeletal muscle attenuation were calculated using computed tomography images and standard tissue attenuation ranges: fat -190– -30 HU; skeletal muscle -29–150 HU. Mean±sd percentage intramuscular fat was higher in the patient group (6.7±3.5% versus 4.3±1.2%, p = 0.03). Both percentage intramuscular fat and skeletal muscle attenuation were associated with physical activity level, exercise capacity and type I fibre proportion, independent of age, mid-thigh cross-sectional area and quadriceps strength. Combined with transfer factor of the lung for carbon monoxide, these variables could identify >80% of patients with fibre type shift with >65% specificity (area under the curve 0.83, 95% CI 0.72–0.95). Skeletal muscle adiposity assessed by computed tomography reflects multiple aspects of COPD related muscle dysfunction and may help to identify patients for trials of interventions targeted at specific muscle phenotypes. PMID:24993908

  17. Skeletal muscle adiposity is associated with physical activity, exercise capacity and fibre shift in COPD.

    PubMed

    Maddocks, Matthew; Shrikrishna, Dinesh; Vitoriano, Simone; Natanek, Samantha A; Tanner, Rebecca J; Hart, Nicholas; Kemp, Paul R; Moxham, John; Polkey, Michael I; Hopkinson, Nicholas S

    2014-11-01

    Quadriceps muscle phenotype varies widely between patients with chronic obstructive pulmonary disease (COPD) and cannot be determined without muscle biopsy. We hypothesised that measures of skeletal muscle adiposity could provide noninvasive biomarkers of muscle quality in this population. In 101 patients and 10 age-matched healthy controls, mid-thigh cross-sectional area, percentage intramuscular fat and skeletal muscle attenuation were calculated using computed tomography images and standard tissue attenuation ranges: fat -190- -30 HU; skeletal muscle -29-150 HU. Mean±sd percentage intramuscular fat was higher in the patient group (6.7±3.5% versus 4.3±1.2%, p = 0.03). Both percentage intramuscular fat and skeletal muscle attenuation were associated with physical activity level, exercise capacity and type I fibre proportion, independent of age, mid-thigh cross-sectional area and quadriceps strength. Combined with transfer factor of the lung for carbon monoxide, these variables could identify >80% of patients with fibre type shift with >65% specificity (area under the curve 0.83, 95% CI 0.72-0.95). Skeletal muscle adiposity assessed by computed tomography reflects multiple aspects of COPD related muscle dysfunction and may help to identify patients for trials of interventions targeted at specific muscle phenotypes.

  18. Spike sorting of muscle spindle afferent nerve activity recorded with thin-film intrafascicular electrodes.

    PubMed

    Djilas, Milan; Azevedo-Coste, Christine; Guiraud, David; Yoshida, Ken

    2010-01-01

    Afferent muscle spindle activity in response to passive muscle stretch was recorded in vivo using thin-film longitudinal intrafascicular electrodes. A neural spike detection and classification scheme was developed for the purpose of separating activity of primary and secondary muscle spindle afferents. The algorithm is based on the multiscale continuous wavelet transform using complex wavelets. The detection scheme outperforms the commonly used threshold detection, especially with recordings having low signal-to-noise ratio. Results of classification of units indicate that the developed classifier is able to isolate activity having linear relationship with muscle length, which is a step towards online model-based estimation of muscle length that can be used in a closed-loop functional electrical stimulation system with natural sensory feedback.

  19. Is fast fiber innervation responsible for increased acetylcholinesterase activity in reinnervating soleus muscles?

    NASA Technical Reports Server (NTRS)

    Misulis, K. E.; Dettbarn, W. D.

    1985-01-01

    An investigation was conducted as to whether the predominantly slow SOL, which is low in AChE activity, is initially reinnervated by axons that originally innervated fast muscle fibers with high AChE activity, such as those of the EDL. Local denervation of the SOL in the guinea pig was performed because this muscle is composed solely of slow (type I) fibers; thereby virtually eliminating the possibility of homologous muscle fast fiber innervation. The overshoot in this preparation was qualitatively similar to that seen with distal denervation in the guinea pig and local and distal denervation in the rat. Thus, initial fast fiber innvervation is not responsible for the patterns of change in AChE activity seen with reinnervation in the SOL. It is concluded that the neural control of AChe is different in these two muscles and may reflect specific differences in the characteristics of AChE regulation in fast and slow muscle.

  20. Estimating muscle activation patterns using a surrogate model of facial biomechanics.

    PubMed

    Wu, Tim; Martens, Harald; Hunter, Peter; Mithraratne, Kumar

    2013-01-01

    Analyzing the muscle activities that drive the expressive facial gestures can be a useful tool in assessing one's emotional state of mind. Since the skin motion is much easier to measure in comparison to the actual electrical excitation signal of facial muscles, a biomechanical model of the human face driven by these muscles can be a useful tool in relating the geometric information to the muscle activity. However, long computational time often hinders its practicality. The objective of this study was to replace the precise but computationally demanding biomechanical model by a much faster multivariate meta-model (surrogate model), such that a significant speedup (real-time interactive speed) can be achieved and data from the biomechanical model can be practically exploited. Using the proposed surrogate, muscle activation patterns of six key facial expressions were estimated in the iterative fit from the structured-light scanned geometric information.

  1. The origin of activity in the biceps brachii muscle during voluntary contractions of the contralateral elbow flexor muscles.

    PubMed

    Zijdewind, Inge; Butler, Jane E; Gandevia, Simon C; Taylor, Janet L

    2006-11-01

    During strong voluntary contractions, activity is not restricted to the target muscles. Other muscles, including contralateral muscles, often contract. We used transcranial magnetic stimulation (TMS) to analyse the origin of these unintended contralateral contractions (termed "associated" contractions). Subjects (n = 9) performed maximal voluntary contractions (MVCs) with their right elbow-flexor muscles followed by submaximal contractions with their left elbow flexors. Electromyographic activity (EMG) during the submaximal contractions was matched to the associated EMG in the left biceps brachii during the right MVC. During contractions, TMS was delivered to the motor cortex of the right or left hemisphere and excitatory motor evoked potentials (MEPs) and inhibitory (silent period) responses recorded from left biceps. Changes at a spinal level were investigated using cervicomedullary stimulation to activate corticospinal paths (n = 5). Stimulation of the right hemisphere produced silent periods of comparable duration in associated and voluntary contractions (218 vs 217 ms, respectively), whereas left hemisphere stimulation caused a depression of EMG but no EMG silence in either contraction. Despite matched EMG, MEPs elicited by right hemisphere stimulation were approximately 1.5-2.5 times larger during associated compared to voluntary contractions (P < 0.005). Similar inhibition of the associated and matched voluntary activity during the silent period suggests that associated activity comes from the contralateral hemisphere and that motor areas in this (right) hemisphere are activated concomitantly with the motor areas in the left hemisphere. Comparison of the MEPs and subcortically evoked potentials implies that cortical excitability was greater in associated contractions than in the matched voluntary efforts.

  2. An Acute Bout of Barefoot Running Alters Lower-limb Muscle Activation for Minimalist Shoe Users.

    PubMed

    Snow, N J; Basset, F A; Byrne, J

    2016-05-01

    Despite the abundance of barefoot running-related research, there have been no electromyography studies evaluating the effects of this mode of exercise on habitual users of minimalist footwear. The present study investigated differences in muscle activation during acute bouts of barefoot and shod running, in minimalist shoe users. 8 male participants ran on a motorized treadmill for 10 min under both conditions, at 70% maximal aerobic speed. Electromyographic data were sampled from the biceps femoris, gluteus maximus, gastrocnemius medialis, tibialis anterior, and vastus lateralis during both swing and stance. Root-mean-square analysis of electromyographic data was conducted to compare muscle activation between conditions. During stance, barefoot running resulted in greater muscle activity in gastrocnemius medialis and gluteus maximus, and lower muscle activity in tibialis anterior. During swing, barefoot running resulted in increased muscle activity in vastus lateralis and gastrocnemius medialus. These results indicate that, for minimalist shoe users, an acute bout of barefoot running results in significantly different lower-limb muscle activity. Increased activation in the above muscles presents a possible mechanism for injury, which should be considered during exercise prescription.

  3. Skeletal Muscle Satellite Cell Activation Following Cutaneous Burn in Rats

    DTIC Science & Technology

    2013-12-01

    mechanisms of long-term muscle atrophy. # 2012 Elsevier Ltd and ISBI. All rights reserved. * Corresponding author at: US Army Institute of Surgical...understanding of the impact of burn on satellite cell functionality will allow us to identify the cellular mechanisms of long-term muscle atrophy after...fibers. J Biophys Biochem Cytol 1961;9:493–5. [12] Hawke TJ, Garry DJ. Myogenic satellite cells: physiology to molecular biology. J