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Sample records for biceps femoris muscles

  1. [Traumatic muscle and tendon ruptures of the lower extremities in sport: adductor muscles, M. rectus femoris and M. biceps femoris].

    PubMed

    Krüger-Franke, M

    2010-12-01

    Ruptures of the adductor muscles, the M. rectus femoris or the M. biceps femoris are sports injuries which need quick and reliable diagnostic management. Treatment of muscle injuries is mostly conservative; complete tendon ruptures or avulsion fractures of the tendons are treated operatively according to the dislocation and the functional loss.

  2. Verbal and visual stimulation effects on rectus femoris and biceps femoris muscles during isometric and concentric

    PubMed Central

    2013-01-01

    Background Coactivation may be both desirable (injury prevention) or undesirable (strength measurement). In this context, different styles of muscle strength stimulus have being investigated. In this study we evaluated the effects of verbal and visual stimulation on rectus femoris and biceps femoris muscles contraction during isometric and concentric. Methods We investigated 13 men (age =23.1 ± 3.8 years old; body mass =75.6 ± 9.1 kg; height =1.8 ± 0.07 m). We used the isokinetic dynamometer BIODEX device and an electromyographic (EMG) system. We evaluated the maximum isometric and isokinetic knee extension and flexion at 60°/s. The following conditions were evaluated: without visual nor verbal command (control); verbal command; visual command and; verbal and visual command. In relation to the concentric contraction, the volunteers performed five reciprocal and continuous contractions at 60°/s. With respect to isometric contractions it was made three contractions of five seconds for flexion and extension in a period of one minute. Results We found that the peak torque during isometric flexion was higher in the subjects in the VVC condition (p > 0.05). In relation to muscle coactivation, the subjects presented higher values at the control condition (p > 0.05). Conclusion We suggest that this type of stimulus is effective for the lower limbs. PMID:24099489

  3. Peroneal nerve compression secondary to an anomalous biceps femoris muscle in an adolescent athlete.

    PubMed

    Kaplan, Kevin M; Patel, Abhay; Stein, Drew A

    2008-05-01

    Common peroneal nerve compression is a well-recognized entity that can cause severe debilitating clinical manifestations. The current literature describes numerous locations and mechanisms of compression, including both structural and systemic causes. Anatomical variants should be considered part of the differential diagnosis in peroneal nerve impingement. We present the case of a 14-year-old basketball player with footdrop secondary to compression of the common peroneal nerve from an accessory biceps femoris muscle, which was treated by neurolysis. In addition, we review the systematic workup of patients with nerve compression.

  4. Physical principles demonstrate that the biceps femoris muscle relative to the other hamstring muscles exerts the most force: implications for hamstring muscle strain injuries

    PubMed Central

    Dolman, Bronwyn; Verrall, Geoffrey; Reid, Iain

    2014-01-01

    Summary Of the hamstring muscle group the biceps femoris muscle is the most commonly injured muscle in sports requiring interval sprinting. The reason for this observation is unknown. The objective of this study was to calculate the forces of all three hamstring muscles, relative to each other, during a lengthening contraction to assess for any differences that may help explain the biceps femoris predilection for injury during interval sprinting. To calculate the displacement of each individual hamstring muscle previously performed studies on cadaveric anatomical data and hamstring kinematics during sprinting were used. From these displacement calculations for each individual hamstring muscle physical principles were then used to deduce the proportion of force exerted by each individual hamstring muscle during a lengthening muscle contraction. These deductions demonstrate that the biceps femoris muscle is required to exert proportionally more force in a lengthening muscle contraction relative to the semimembranosus and semitendinosus muscles primarily as a consequence of having to lengthen over a greater distance within the same time frame. It is hypothesized that this property maybe a factor in the known observation of the increased susceptibility of the biceps femoris muscle to injury during repeated sprints where recurrent higher force is required. PMID:25506583

  5. Short-latency crossed responses in the human biceps femoris muscle

    PubMed Central

    Stevenson, Andrew J T; Kamavuako, Ernest N; Geertsen, Svend S; Farina, Dario; Mrachacz-Kersting, Natalie

    2015-01-01

    Interlimb reflexes contribute to the central neural co-ordination between different limbs in both humans and animals. Although commissural interneurons have only been directly identified in animals, spinally-mediated interlimb reflexes have been discovered in a number of human lower limb muscles, indicating their existence in humans. The present study aimed to investigate whether short-latency crossed-spinal reflexes are present in the contralateral biceps femoris (cBF) muscle following ipsilateral knee (iKnee) joint rotations during a sitting task, where participants maintained a slight pre-contraction in the cBF. Following iKnee extension joint rotations, an inhibitory reflex was observed in the surface electromyographic (EMG) activity of the cBF, whereas a facilitatory reflex was observed in the cBF following iKnee flexion joint rotations. The onset latency of both cBF reflexes was 44 ms, which is too fast for a transcortical pathway to contribute. The cBF inhibitory and facilitatory reflexes followed the automatic gain control principle, with the size of the response increasing as the level of background pre-contraction in the cBF muscle increased. In addition to the surface EMG, both short-latency inhibitory and facilitatory cBF reflexes were recorded directly at the motor unit level by i.m. EMG, and the same population of cBF motor units that were inhibited following iKnee extension joint rotations were facilitated following iKnee flexion joint rotations. Therefore, parallel interneuronal pathways (probably involving commissural interneurons) from ipsilateral afferents to common motoneurons in the contralateral leg can probably explain the perturbation direction-dependent reversal in the sign of the short-latency cBF reflex. PMID:25970767

  6. Neurovascularized free short head of the biceps femoris muscle transfer for one-stage reanimation of facial paralysis.

    PubMed

    Hayashi, Akiteru; Maruyama, Yu

    2005-02-01

    The single-stage technique for cross-face reanimation of the paralyzed face without nerve graft is an improvement over the two-stage procedure because it results in early reinnervation of the transferred muscle and shortens the period of rehabilitation. On the basis of an anatomic investigation, the short head of the biceps femoris muscle with attached lateral intermuscular septum of the thigh was identified as a new candidate for microneurovascular free muscle transfer. The authors performed one-stage transfer of the short head of the biceps femoris muscle with a long motor nerve for reanimation of established facial paralysis in seven patients. The dominant nutrient vessels of the short head were the profunda perforators (second or third) in six patients and the direct branches from the popliteal vessels in one patient. The recipient vessels were the facial vessels in all cases. The length of the motor nerve of the short head ranged from 10 to 16 cm, and it was sutured directly to several zygomatic and buccal branches of the contralateral facial nerve in six patients. One patient required an interpositional nerve graft of 3 cm to reach the suitable facial nerve branches on the intact side. The period required for initial voluntary movement of the transferred muscles ranged from 4 to 10 months after the procedures. The period of postoperative follow-up ranged from 5 to 42 months. Transfer of the vascularized innervated short head of the biceps femoris muscle is thought to be an alternative for one-stage reconstruction of the paralyzed face because of the reliable vascular anatomy of the muscle and because it allows two teams to operate together without the need to reposition the patient. The nerve to the short head of the biceps femoris enters the side opposite the vascular pedicle of the muscle belly, and this unique relationship between the vascular pedicle and the motor nerve is anatomically suitable for one-stage reconstruction of the paralyzed face. As much

  7. Musculotendon variability influences tissue strains experienced by the biceps femoris long head muscle during high-speed running.

    PubMed

    Fiorentino, Niccolo M; Blemker, Silvia S

    2014-10-17

    The hamstring muscles frequently suffer injury during high-speed running, though the factors that make an individual more susceptible to injury remain poorly understood. The goals of this study were to measure the musculotendon dimensions of the biceps femoris long head (BFlh) muscle, the hamstring muscle injured most often, and to use computational models to assess the influence of variability in the BFlh's dimensions on internal tissue strains during high-speed running. High-resolution magnetic resonance (MR) images were acquired over the thigh in 12 collegiate athletes, and musculotendon dimensions were measured in the proximal free tendon/aponeurosis, muscle and distal free tendon/aponeurosis. Finite element meshes were generated based on the average, standard deviation and range of BFlh dimensions. Simulation boundary conditions were defined to match muscle activation and musculotendon length change in the BFlh during high-speed running. Muscle and connective tissue dimensions were found to vary between subjects, with a coefficient of variation (CV) of 17±6% across all dimensions. For all simulations peak local strain was highest along the proximal myotendinous junction, which is where injury typically occurs. Model variations showed that peak local tissue strain increased as the proximal aponeurosis width narrowed and the muscle width widened. The aponeurosis width and muscle width variation models showed that the relative dimensions of these structures influence internal muscle tissue strains. The results of this study indicate that a musculotendon unit's architecture influences its strain injury susceptibility during high-speed running.

  8. The physical and biochemical changes in springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum and Biceps femoris muscle during ageing.

    PubMed

    North, M K; Frylinck, L; Hoffman, L C

    2015-12-01

    This study aimed to determine the optimum ageing period for vacuum-packed springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum (LTL) and Biceps femoris (BF) muscle stored at 5.4 ± 1.0°C. Portions of muscle from seven male and six female springbok were aged 1, 2, 5, 8, 14 or 21 days. The Warner Bratzler shear force declined most during the first five days post-mortem (PM), while purge and cooking losses increased significantly with ageing. Calpains I and II and calpastatin activity declined significantly up to five days PM, suggesting that they may be responsible for tenderization. Cathepsins B, BL and H activity increased significantly during ageing. The BF muscle had significantly higher pH, lower purge loss, higher cooking loss, higher WBSF and higher calpain and calpastatin activity than the LTL. No significant differences between the genders or muscles were found for the collagen content or collagen solubility. Springbok LTL and BF muscles should not be aged for longer than five days. PMID:26225930

  9. The physical and biochemical changes in springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum and Biceps femoris muscle during ageing.

    PubMed

    North, M K; Frylinck, L; Hoffman, L C

    2015-12-01

    This study aimed to determine the optimum ageing period for vacuum-packed springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum (LTL) and Biceps femoris (BF) muscle stored at 5.4 ± 1.0°C. Portions of muscle from seven male and six female springbok were aged 1, 2, 5, 8, 14 or 21 days. The Warner Bratzler shear force declined most during the first five days post-mortem (PM), while purge and cooking losses increased significantly with ageing. Calpains I and II and calpastatin activity declined significantly up to five days PM, suggesting that they may be responsible for tenderization. Cathepsins B, BL and H activity increased significantly during ageing. The BF muscle had significantly higher pH, lower purge loss, higher cooking loss, higher WBSF and higher calpain and calpastatin activity than the LTL. No significant differences between the genders or muscles were found for the collagen content or collagen solubility. Springbok LTL and BF muscles should not be aged for longer than five days.

  10. Neuromuscular efficiency of the vastus lateralis and biceps femoris muscles in individuals with anterior cruciate ligament injuries☆

    PubMed Central

    Aragão, Fernando Amâncio; Schäfer, Gabriel Santo; de Albuquerque, Carlos Eduardo; Vituri, Rogério Fonseca; de Azevedo, Fábio Mícolis; Bertolini, Gladson Ricardo Flor

    2015-01-01

    Objective To analyze strength and integrated electromyography (IEMG) data in order to determine the neuromuscular efficiency (NME) of the vastus lateralis (VL) and biceps femoris (BF) muscles in patients with anterior cruciate ligament (ACL) injuries, during the preoperative and postoperative periods; and to compare the injured limb at these two times, using the non-operated limb as a control. Methods EMG data and BF and VL strength data were collected during three maximum isometric contractions in knee flexion and extension movements. The assessment protocol was applied before the operation and two months after the operation, and the NME of the BF and VL muscles was obtained. Results There was no difference in the NME of the VL muscle from before to after the operation. On the other hand, the NME of the BF in the non-operated limb was found to have increased, two months after the surgery. Conclusions The NME provides a good estimate of muscle function because it is directly related to muscle strength and capacity for activation. However, the results indicated that two months after the ACL reconstruction procedure, at the time when loading in the open kinetic chain within rehabilitation protocols is usually started, the neuromuscular efficiency of the VL and BF had still not been reestablished. PMID:26229914

  11. The changes in springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum and Biceps femoris muscles during the rigour period.

    PubMed

    North, M K; Frylinck, L; Hoffman, L C

    2016-02-01

    This study describes the changes taking place during rigour in springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum (LTL) and Biceps femoris (BF) muscles. Samples from six male and six female springbok were snap-frozen at 2, 3, 5, 8, 12, 18, 24 and 30h post-mortem (PM) and the pH, calpains I, II and calpastatin activities and cathepsins B, BL and H activities were determined. The temperature was also recorded. Significant third-order interactions were found for the pH and temperature, with the female LTL cooling more rapidly and acidifying slower than the other samples. Female muscles were at risk of developing cold-shortening and all the samples cooled more rapidly than recommended for cattle or sheep. Cathepsin BL activity increased PM, likely due to the degradation of the lysosomes. Calpains I, II and calpastatin activity declined during rigour, indicating that the calpains were activated early PM. Gender and muscle had a significant effect on calpain and cathepsin activity.

  12. Distal Insertions of the Biceps Femoris

    PubMed Central

    Branch, Eric A.; Anz, Adam W.

    2015-01-01

    Background: Avulsion of the biceps femoris from the fibula and proximal tibia is encountered in clinical practice. While the anatomy of the primary posterolateral corner structures has been qualitatively and quantitatively described, a quantitative analysis regarding the insertions of the biceps femoris on the fibula and proximal tibia is lacking. Purpose: To quantitatively assess the insertions of the biceps femoris, fibular collateral ligament (FCL), and anterolateral ligament (ALL) on the fibula and proximal tibia as well as establish relationships among these structures and to pertinent surgical anatomy. Study Design: Descriptive laboratory study. Methods: Dissections were performed on 12 nonpaired, fresh-frozen cadaveric specimens identifying the biceps femoris, FCL, and ALL, and their insertions on the proximal tibia and fibula. The footprint areas, orientations, and distances from relevant osseous landmarks were measured using a 3-dimensional coordinate measurement device. Results: Dissection produced 6 easily identifiable and reproducible anatomic footprints. Tibial footprints included the insertion of the ALL and an insertion of the biceps femoris (TBF). Fibular footprints included the insertion of the FCL, a distal insertion of the biceps femoris (DBF), a medial footprint of the biceps femoris (MBF), and a proximal footprint of the biceps femoris (PBF). The mean area of these footprints (95% CI) was as follows: ALL, 53.0 mm2 (38.4-67.6); TBF, 93.9 mm2 (72.0-115.8); FCL, 86.8 mm2 (72.3-101.2); DBF, 119 mm2 (91.1-146.9); MBF, 46.8 mm2 (29.0-64.5); and PBF, 215 mm2 (192.4-237.5). The mean distance (95% CI) from the Gerdy tubercle to the center of the ALL footprint was 24.3 mm (21.6-27.0) and to the center of the TBF was 22.5 mm (21.0-24.0). The center of the DBF was 8.68 mm (7.0-10.3) from the anterior border of the fibula, the center of the FCL was 14.6 mm (12.5-16.7) from the anterior border of the fibula and 20.7 mm (19.0-22.4) from the tip of the fibular

  13. Changes in the Range of Motion of the Hip Joint and the Muscle Activity of the Rectus Femoris and Biceps Femoris of Stroke Patients during Obstacles Crossing on the Ground and Underwater.

    PubMed

    Kim, Myung-Chul; Han, Seul-Ki; Kim, Seung-Kyun

    2014-08-01

    [Purpose] The purpose of this study was to examine range of motion (ROM) and the muscle activity of stroke patients during obstacle task on the ground and underwater. [Subjects] The subjects of this study were seven stroke patients in a hospital located in Daejeon, South Korea. [Methods] The measurements in this study were conducted in an exercise therapy room and a pool dedicated to underwater exercise (water temperature 33.5 °C, air temperature 27 °C) in the hospital building. The pool's water depth was determined by considering the levels of the xiphoid process of the study subjects. Ten-centimeter-high obstacles were used. An electrogoniometer was used to examine the ROM of flexion and extension of the hip joints on the affected side. An MP150 system a BioNomadix 2-channel wireless EMG transmitter was used to examine the muscle activity of the rectus femoris and biceps femoris of the affected side. [Conclusion] The results suggest that the unaffected side was supported, that the affected side moved, and that the hip joint was bent more underwater than on the ground. The rectus femoris and bicpes femoris were activated significantly less underwater than on the ground in all sections.

  14. Biceps femoris tendon injuries sustained while playing hockey

    PubMed Central

    Watura, Christopher; Harries, William

    2011-01-01

    A 42-year-old female nurse presented in March 2008 with a left proximal hamstring tendon injury sustained while playing hockey. At surgery, the proximal biceps femoris tendon and semitendonosus were found to be ruptured and were repaired. The patient made a good recovery but sustained a further hockey injury in January 2010 involving a complete tear and rupture of the biceps femoris tendon distally. This was managed conservatively and the patient was able to return to playing hockey 10 months later. Biceps femoris tendon injuries have been reported in sport but this is the first documented case of the injury occurring while playing hockey and is also the first reported case of a biceps tendon rupture proximally (hamstring tendon) followed by distal biceps femoris rupture at the knee in the same leg. PMID:22715185

  15. Effects of live weight at slaughter on fatty acid composition of Longissimus dorsi and Biceps femoris muscles of indigenous Lori goat.

    PubMed

    Kiani, Ali; Fallah, Rozbeh

    2016-01-01

    This study aimed to determine fatty acid (FA) composition of Longissimus dorsi (LD) and Biceps femoris (BF) muscles of an Iranian indigenous goat (Lori goat) at two live weights at slaughter (LWS). Twenty male Lori goats (5 to 8 months) raised in nomadic system were slaughtered either at LWS less than 20 kg (light) or LWS more than 30 kg (heavy). Carcass dressing and FA composition of intramuscular fat of LD and BF muscles as well as cholesterol content of LD muscle were determined. Heavy goats had higher dressing percentage than light ones (42.7vs.39.3%, P < 0.01). The predominant n-6 FA were C18:2, and C20:4 while C22:5, C20:5, C18:3, C20:3, and C22:6 were the n-3 FA detected. Polyunsaturated and saturated FA contributed 22% and 36% of the total FA in both muscles, respectively. Palmitic acid (C16:0) of LD was higher in heavy compared to the light goats (P < 0.05). BF muscle had higher α-linolenic acid (18:3 n-3) as percentage than LD muscle (P < 0.05). The ratio of n-6/n-3 FA and polyunsaturated/saturated FA were 3.8 and 0.6, respectively. Cholesterol content of LD muscle of light and heavy goats were 71.2 ± 16 and 59.5 ± 14 mg per 100 g fresh meat respectively. In conclusion, desirable PUFA/SFA (0.6) and n-3/n-6 ratio (3.8) found in indigenous Lori goat propose healthy source of lean meat for the consumers.

  16. Quality traits in muscle biceps femoris and back-fat from purebred Iberian and reciprocal Iberian×Duroc crossbred pigs.

    PubMed

    Ventanas, Sonia; Ventanas, Jesús; Jurado, Angela; Estévez, Mario

    2006-08-01

    The present study evaluated the physico-chemical characteristics of muscle biceps femoris and back-fat from purebred Iberian (PBI) pigs and reciprocal crossbred Iberian×Duroc pigs (IB×D pigs: Iberian dams×Duroc sires; D×IB pigs: Duroc dams×Iberian sires). Muscles from PBI pigs contained significantly higher amounts of IMF, heme pigments and iron than those from crossbred pigs. In addition, muscles from PBI pigs were darker (lower L(∗)-values) and redder (higher a(∗)-values) and exhibited a more intense colour (higher chroma value) which was closer to the true red axis (lower hue value) than muscles from crossbred pigs. Back-fat from PBI pigs had significantly higher percentages of monounsaturated fatty acids (MUFA) and significantly smaller percentages of polyunsaturated fatty acids (PUFA) than those from crossbred pigs. Regarding the fatty acid profiles of the muscle lipid fractions, the genetic background particularly affected the composition of the polar lipid (PL) fraction. PL in muscles from PBI pigs contained significantly higher proportions of oleic acid and total MUFA and significantly lower amounts of arachidonic acid, certain long-chain PUFA (ω-6 and ω-3 fatty acids) and total amount of PUFA than PL in muscles from crossbred pigs. The results obtained indicate that tissues from PBI pigs would be more suitable for the production of dry-cured meats than those from cross-bred pigs. The position of the dam or the sire in reciprocal Iberian×Duroc crosses had no clear effects on meat quality.

  17. The use of dielectric properties and other physical analyses for assessing protein denaturation in beef biceps femoris muscle during cooking from 5 to 85°C.

    PubMed

    Brunton, N P; Lyng, J G; Zhang, L; Jacquier, J C

    2006-02-01

    Dielectric properties of beef biceps femoris muscle were recorded during heating (5-85°C) to assess their linkage to phase changes monitored by differential scanning calorimetry (DSC) and rheology. DSC indicated endotherms between 56 and 81°C corresponding to denaturation of actin, collagen and myosin. Matching changes in dielectric properties (dielectric constant (ε') and loss factor (ε″)) were noted at radio and/or microwave frequencies though the nature of the change differed depending upon frequency. The main observation in ε' was an increase above 65-66°C, most likely due to fluid release on collagen denaturation. This fluid plus liquid from myosin denaturation most likely solvated ions freed during myosin denaturation which manifested as an ε″ increase. However, it must be noted that meat structural protein denaturation is compounded with physical shrinkage which can also influence dielectric properties. Rheological parameters of beef muscle heated from 5 to 85°C also displayed marked changes relating to structural protein denaturation.

  18. Effects of fibre type and structure of longissimus lumborum (Ll), biceps femoris (Bf) and semimembranosus (Sm) deer muscles salting with different Nacl addition on proteolysis index and texture of dry-cured meats.

    PubMed

    Żochowska-Kujawska, J

    2016-11-01

    The aim of the present study was to describe the effect of fibre type and structure as well as NaCl level on the proteolysis index and texture parameters observed in dry-cured meats produced from individual deer muscles. The biceps femoris, semimembranosus and longissimus lumborum muscles were cut from deer main elements, shaped into blocks by trimming off the edges, cured by adding 4, 6 and 8% of salt (w/w) and dried in a ripening chamber for 29days. The results indicated that deer dry-cured muscles with higher percentage of red fibres (type I) showed higher texture parameters, proteolysis index as well as lower moisture losses than muscles with higher amount of white fibres (type IIB). Dry-cured deer muscles with lower NaCl content showed higher values of proteolysis index and lower hardness, cohesiveness, springiness, and chewiness, as well as lower changes in structure elements. PMID:27442183

  19. Muscle activity response to external moment during single-leg drop landing in young basketball players: the importance of biceps femoris in reducing internal rotation of knee during landing.

    PubMed

    Fujii, Meguru; Sato, Haruhiko; Takahira, Naonobu

    2012-01-01

    Internal tibial rotation with the knee close to full extension combined with valgus collapse during drop landing generally results in non-contact anterior cruciate ligament (ACL) injury. The purpose of this study was to investigate the relationship between internal rotation of the knee and muscle activity from internal and external rotator muscles, and between the internal rotation of knee and externally applied loads on the knee during landing in collegiate basketball players. Our hypothesis was that the activity of biceps femoris muscle would be an important factor reducing internal knee rotation during landing. The subjects were 10 collegiate basketball students: 5 females and 5 males. The subjects performed a single-leg drop landing from a 25-cm height. Femoral and tibial kinematics were measured using a 3D optoelectronic tracking system during the drop landings, and then the knee angular motions were determined. Ground reaction forces and muscle activation patterns (lateral hamstring and medial hamstring) were simultaneously measured and computed. Results indicated that lower peak internal tibial rotation angle at the time of landing was associated with greater lateral hamstring activity (r = -0.623, p < 0.001). When gender was considered, the statistically significant correlation remained only in females. There was no association between the peak internal tibial rotation angle and the knee internal rotation moment. Control of muscle activity in the lateral to medial hamstring would be an important factor in generating sufficient force to inhibit excessive internal rotation during landing. Strengthening the biceps femoris might mitigate the higher incidence of non-contact ACL injury in female athletes. Key pointsLower activity of the external rotator muscle of the knee, which inhibits internal rotation of the knee, may be the reason why females tend to show a large internal rotation of the knee during drop landing.Externally applied internal rotation moment of

  20. Tenderization effect of soy sauce on beef M. biceps femoris.

    PubMed

    Kim, Hyun-Wook; Choi, Yun-Sang; Choi, Ji-Hun; Kim, Hack-Youn; Lee, Mi-Ai; Hwang, Ko-Eun; Song, Dong-Heon; Lim, Yun-Bin; Kim, Cheon-Jei

    2013-08-15

    This study was conducted to evaluate the tenderization effect of soy sauce on beef M. biceps femoris (BF). Five marinades were prepared with 4% (w/v) sodium chloride and 25% (w/v) soy sauce solutions (4% salt concentration) and mixed with the ratios of 100:0 (S0, pH 6.52), 75:25 (S25, 5.40) 50:50 (S50, 5.24), 25:75 (S75, 5.05), and 0:100 (S100, 4.85), respectively. The BF samples which were obtained from Hanwoo cows at 48 h postmortem (n=24) were marinated with five marinades for 72 h at 4°C (1:4 w/w), and the effects of soy sauce on tenderness were evaluated. Soy sauce marination resulted in a decrease in the pH value of the BF sample. However, there were no significant differences in the water holding capacity (P<0.05). The S100 treatment showed the significant (P<0.05) increase in collagen solubility and myofibrillar fragmentation index, contributing to decreased shear force compared to S0 (control). Reduction in intensity of few myofibrillar protein bands were observed for S100 treatment compared to control using SDS-PAGE. Scanning electron microscopy revealed breakdown of connective tissue surrounding muscle fibers of the S100 treatment. The tenderization effect of soy sauce may attribute various mechanisms such as increased collagen solubility or proteolysis which depend on soy sauce level in marinade. PMID:23561150

  1. Split biceps femoris tendon reconstruction for proximal tibiofibular joint instability.

    PubMed

    Mena, H; Brautigan, B; Johnson, D L

    2001-07-01

    Recurrent instability of the proximal tibiofibular joint is an infrequently diagnosed abnormality. We present a new technique for reconstructing the joint using a split biceps femoris tendon passed through a bone tunnel in both the proximal tibial metaphysis and fibular head. The case report is also presented. The procedure offers an anatomic reconstruction and firm stabilization. It allows normal motion of the proximal tibiofibular joint and preserves the normal mechanics of the ankle. This procedure is an excellent alternative to resection of the fibular head, transarticular arthrodesis, or pseudoarthrosis focus at the fibular head.

  2. Use of Ultrasound to Monitor Biceps Femoris Mechanical Adaptations after Injury in a Professional Soccer Player

    PubMed Central

    Kellis, Eleftherios; Galanis, Nikiforos; Chrysanthou, Chrysanthos; Kofotolis, Nikolaos

    2016-01-01

    This study examined the use of ultrasound to monitor changes in the long head of the biceps femoris (BF) architecture of aprofessional soccer player with acute first-time hamstring strain. The player followed a 14 session physiotherapy treatment until return to sport. The pennation angle and aponeurosis strain of the long head of the biceps femoris (BF) were monitored at 6 occasions (up until 1 year) after injury. The size of the scar / hematoma was reduced by 63.56% (length) and 67.9% (width) after the intervention and it was almost non-traceable one year after injury. The pennation angle of the fascicles underneath the scar showed a decline of 51.4% at the end of the intervention while an increase of 109.2% of the fascicles which were closer to deep aponeurosis was observed. In contrast, pennation angle of fascicles located away from the injury site were relatively unaffected. The treatment intervention resulted in a 57.9% to 77.3% decline of maximum strain per unit of MVC moment and remained similar one year after the intervention. This study provided an example of the potential use of ultrasound-based parameters to link the mechanical adaptations of the injured muscle to specific therapeutic intervention. Key points Changes in fascicle orientation after biceps femoris mild tear were reduced after a 28 day intervention and remained similar one year after injury. Tendon/aponeurosis strain per unit of moment of force decreased during the course of the therapeutic intervention. Future studies could utilize ultrasonography to monitor mechanical responses after various types of hamstring injury and interventions in order to improve criteria for a safe return to sport. PMID:26957929

  3. Use of Ultrasound to Monitor Biceps Femoris Mechanical Adaptations after Injury in a Professional Soccer Player.

    PubMed

    Kellis, Eleftherios; Galanis, Nikiforos; Chrysanthou, Chrysanthos; Kofotolis, Nikolaos

    2016-03-01

    This study examined the use of ultrasound to monitor changes in the long head of the biceps femoris (BF) architecture of aprofessional soccer player with acute first-time hamstring strain. The player followed a 14 session physiotherapy treatment until return to sport. The pennation angle and aponeurosis strain of the long head of the biceps femoris (BF) were monitored at 6 occasions (up until 1 year) after injury. The size of the scar / hematoma was reduced by 63.56% (length) and 67.9% (width) after the intervention and it was almost non-traceable one year after injury. The pennation angle of the fascicles underneath the scar showed a decline of 51.4% at the end of the intervention while an increase of 109.2% of the fascicles which were closer to deep aponeurosis was observed. In contrast, pennation angle of fascicles located away from the injury site were relatively unaffected. The treatment intervention resulted in a 57.9% to 77.3% decline of maximum strain per unit of MVC moment and remained similar one year after the intervention. This study provided an example of the potential use of ultrasound-based parameters to link the mechanical adaptations of the injured muscle to specific therapeutic intervention. Key pointsChanges in fascicle orientation after biceps femoris mild tear were reduced after a 28 day intervention and remained similar one year after injury.Tendon/aponeurosis strain per unit of moment of force decreased during the course of the therapeutic intervention.Future studies could utilize ultrasonography to monitor mechanical responses after various types of hamstring injury and interventions in order to improve criteria for a safe return to sport. PMID:26957929

  4. Entrapment of Common Peroneal Nerve by Surgical Suture following Distal Biceps Femoris Tendon Repair

    PubMed Central

    Nakazora, Shigeto; Kato, Ko

    2016-01-01

    We describe entrapment of the common peroneal nerve by a suture after surgical repair of the distal biceps femoris tendon. Complete rupture of the distal biceps femoris tendon of a 16-year-old male athlete was surgically repaired. Postoperative common peroneal nerve palsy was evident, but conservative treatment did not cause any neurological improvement. Reexploration revealed that the common peroneal nerve was entrapped by the surgical suture. Complete removal of the suture and external neurolysis significantly improved the palsy. The common peroneal nerve is prone to damage as a result of its close proximity to the biceps femoris tendon and it should be identified during surgical repair of a ruptured distal biceps femoris tendon. PMID:27703826

  5. Long head of biceps femoris flap in anal fistula treatment: anatomical study and case report.

    PubMed

    Terryn, F X; Leonard, D; Chateau, F

    2015-01-01

    In case of complex anal fistulae, the treatment can include muscular flaps. The gracilis transposition flap is the gold-standard in perineal reconstructive surgery, with wide use during the past decades. However, in some cases, this flap is too short to reach difficult locations such as the posterior perineum. The long head of the biceps femoris, which has already been studied in the electrically stimulated neosphincter formation, could be more appropriate in such clinical situations. Furthermore, its potential advantages, amongst which an excellent functional outcome, would be to allow persistent prone position, during both treatment and reconstruction, as well as a more favorable intramuscular vascularisation. We report the case of a 39-year-old man with a complex recurrent transphincteric posterior anal fistula with an external orifice in the right buttock and complicated with a severe cellulitis, treated with an endo-anal flap combined with a long head of biceps femoris pediculised flap. PMID:26021955

  6. Calcific tendinitis of biceps femoris: an unusual site and cause for lateral knee pain.

    PubMed

    Chan, Warwick; Chase, Helen Emily; Cahir, John G; Walton, Neil Patrick

    2016-01-01

    A 37-year-old man presented to the acute knee and sports medicine clinic with atraumatic lateral knee pain. He had point tenderness over the lateral aspect of his knee which had not settled with anti-inflammatory medications. Imaging revealed a large opaque lesion lateral to the knee and although there was no clear mechanism, injury to the posterolateral corner was considered. An MRI subsequently revealed a rare case of calcific tendinitis to the biceps femoris tendon insertion. This condition was self-limiting and did not require interventions such as steroid injections. This is the first reported case of calcific tendinitis of biceps femoris as a cause of acute knee pain. PMID:27473032

  7. Anatomical reconstruction of popliteofibular ligament using looped biceps femoris tendon: a case report.

    PubMed

    Watanabe, Nobuyoshi; Yoshino, Nobuyuki; Fukuda, Yukihisa; Fujita, Nobuhiko; Takai, Shinro

    2008-04-01

    We describe a case of popliteofibular ligament (PFL) injury, successfully treated with a new anatomic reconstruction technique looping the biceps femoris tendon (BT). The anterior half of the BT was split longitudinally from the fibular insertion, cut at the proximal end and left attached at the insertion. The proximal end of the BT was looped back in a slit made in the popliteal tendon (PT) at the original anatomical insertion site of the PFL, and passed through the tunnel from the posterior and the baseball suture was tightened on the anterior cortex of fibular head.

  8. Amplitude and frequency changes in surface EMG of biceps femoris during five days Bruce Protocol treadmill test.

    PubMed

    Jamaluddin, Fauzani N; Ahmad, Siti A; Noor, Samsul Bahari Mohd; Hassan, Wan Zuha Wan; Yaakob, Azhar; Adam, Yunus; Ali, Sawal H M

    2015-08-01

    Electromyography (EMG) is one of the indirect tools in indexing fatigue. Fatigue can be detected when there are changes on amplitude and frequency. However, various outcomes from literature make researchers conclude that EMG is not a reliable tool to measure fatigue. This paper investigates EMG behavior of biceps femoris in median frequency and mean absolute value during five days of Bruce Protocol treadmill test. Before that, surface EMG signals are filtered using band pass filter cut-off at 20-500Hz and are de-noised using db45 1-decimated wavelet transform. Five participants achieved more than 85% of their maximal heart rate during the running activity. The authors also consider other markers of fatigue such as performance, muscle soreness and lethargy as indicators to adaptation and maladaptation conditions. Result shows that turning points of median frequency and mean absolute value are very significant in indexing fatigue and indicators to adaptation of resistive training. PMID:26737713

  9. Effects of sodium chloride, phosphate type and concentration, and pump rate on beef biceps femoris quality and sensory characteristics.

    PubMed

    Baublits, R T; Pohlman, F W; Brown, A H; Johnson, Z B

    2005-06-01

    Beef biceps femoris muscles (n=45) were used to evaluate the effect of enhancement with solutions comprising 2.0% sodium chloride and either sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP), or tetrasodium pyrophosphate (TSPP) at either 0.2% or 0.4% of product weight. All solutions were injected into muscle samples at either 112% (12% pump) or 118% (18% pump) of raw product weight. Muscles treated with all three phosphate types had decreased (P<0.05) free water compared to untreated muscles (CNT), and while TSPP-treated muscles were able to bind greater (P<0.05) additional water than CNT, STPP- and SHMP-treated muscles did not differ (P>0.05) from CNT. Disregarding phosphate type, steaks with 0.4% phosphate inclusion bound more (P<0.05) water than those with 0.2% phosphate inclusion. Steaks treated with STPP or TSPP had decreased (P<0.05) cooking losses than CNT, while SHMP-treated steaks did not differ (P>0.05) from CNT. Steaks injected at 18% pump had greater (P<0.05) percent moisture, and did not differ (P>0.05) in free water, water binding, or cooking losses from steaks injected at 12% pump. Although there were no differences (P>0.05) in Warner-Bratzler shear force in this study, steaks with SHMP, STPP, and TSPP all were rated more tender, and juicier (P<0.05) by sensory panelists than CNT steaks or steaks enhanced only with sodium chloride. Regardless of phosphate type, steaks enhanced with 0.4% phosphate and those steaks at 18% pump received improved (P<0.05) sensory tenderness ratings compared to 0.2% phosphate and 12% pump, respectively. These results suggest that enhancing biceps femoris muscles with STPP or TSPP can improve water retention, yield, and palatability characteristics. Additionally, enhancement with a phosphate/salt solution at an 18% pump rate, compared to a 12% pump rate, can allow for improved sensory tenderness perceptions without decreasing product yields.

  10. Knee flexor strength and bicep femoris electromyographical activity is lower in previously strained hamstrings.

    PubMed

    Opar, David A; Williams, Morgan D; Timmins, Ryan G; Dear, Nuala M; Shield, Anthony J

    2013-06-01

    The aim of this study was to determine if athletes with a history of hamstring strain injury display lower levels of surface EMG (sEMG) activity and median power frequency in the previously injured hamstring muscle during maximal voluntary contractions. Recreational athletes were recruited, 13 with a history of unilateral hamstring strain injury and 15 without prior injury. All athletes undertook isokinetic dynamometry testing of the knee flexors and sEMG assessment of the biceps femoris long head (BF) and medial hamstrings (MHs) during concentric and eccentric contractions at ±180 and ±60°s(-1). The knee flexors on the previously injured limb were weaker at all contraction speeds compared to the uninjured limb (+180°s(-1)p=0.0036; +60°s(-1)p=0.0013; -60°s(-1)p=0.0007; -180°s(-1)p=0.0007) whilst sEMG activity was only lower in the BF during eccentric contractions (-60°s(-1)p=0.0025; -180°s(-1)p=0.0003). There were no between limb differences in MH sEMG activity or median power frequency from either BF or MH in the injured group. The uninjured group showed no between limb differences in any of the tested variables. Secondary analysis comparing the between limb difference in the injured and the uninjured groups, confirmed that previously injured hamstrings were mostly weaker (+180°s(-1)p=0.2208; +60°s(-1)p=0.0379; -60°(-1)p=0.0312; -180°s(-1)p=0.0110) and that deficits in sEMG were confined to the BF during eccentric contractions (-60°s(-1)p=0.0542; -180°s(-1)p=0.0473). Previously injured hamstrings were weaker and BF sEMG activity was lower than the contralateral uninjured hamstring. This has implications for hamstring strain injury prevention and rehabilitation which should consider altered neural function following hamstring strain injury.

  11. Influence of extended aging on beef quality characteristics and sensory perception of steaks from the biceps femoris and semimembranosus.

    PubMed

    Colle, M J; Richard, R P; Killinger, K M; Bohlscheid, J C; Gray, A R; Loucks, W I; Day, R N; Cochran, A S; Nasados, J A; Doumit, M E

    2016-09-01

    The objective was to determine the influence of post-fabrication aging (2, 14, 21, 42, and 63days) on beef quality characteristics and consumer sensory perception of biceps femoris (BF) and semimembranosus (SM) steaks. Lipid oxidation and aerobic plate counts increased (P<0.05) with longer aging periods and retail display times. An aging period by day of retail display interaction (P<0.05) was observed for a* and b* values of the BF and SM. Warner-Bratzler shear force values decreased (P<0.05) with longer aging for the SM, while no difference was observed for the BF. Consumer panel results revealed that longer aging periods increased (P<0.05) acceptability of the SM, tenderness of both muscles, and tended to increase (P=0.07) juiciness of the SM. Our results show that extended aging reduces retail color stability yet has positive effects on consumer perception of tenderness of both muscles and overall acceptability of the SM. PMID:27155799

  12. Reduced biceps femoris myoelectrical activity influences eccentric knee flexor weakness after repeat sprint running.

    PubMed

    Timmins, R G; Opar, D A; Williams, M D; Schache, A G; Dear, N M; Shield, A J

    2014-08-01

    The aim of this study was to determine whether declines in knee flexor strength following overground repeat sprints were related to changes in hamstrings myoelectrical activity. Seventeen recreationally active men completed maximal isokinetic concentric and eccentric knee flexor strength assessments at 180°/s before and after repeat sprint running. Myoelectrical activity of the biceps femoris (BF) and medial hamstrings (MHs) was measured during all isokinetic contractions. Repeated measures mixed model [fixed factors = time (pre- and post-repeat sprint) and leg (dominant and nondominant), random factor = participants] design was fitted with the restricted maximal likelihood method. Repeat sprint running resulted in significant declines in eccentric, and concentric, knee flexor strength (eccentric = 26 ± 4 Nm, 15% P < 0.001; concentric 11 ± 2 Nm, 10% P < 0.001). Eccentric BF myoelectrical activity was significantly reduced (10%; P = 0.035). Concentric BF and all MH myoelectrical activity were not altered. The declines in maximal eccentric torque were associated with the change in eccentric BF myoelectrical activity (P = 0.013). Following repeat sprint running, there were preferential declines in the myoelectrical activity of the BF, which explained declines in eccentric knee flexor strength.

  13. Treatment of Ischial Pressure Sores with Both Profunda Femoris Artery Perforator Flaps and Muscle Flaps

    PubMed Central

    Kim, Chae Min; Yun, In Sik; Lee, Dong Won; Lew, Dae Hyun; Rah, Dong Kyun

    2014-01-01

    Background Reconstruction of ischial pressure sore defects is challenging due to extensive bursas and high recurrence rates. In this study, we simultaneously applied a muscle flap that covered the exposed ischium and large bursa with sufficient muscular volume and a profunda femoris artery perforator fasciocutaneous flap for the management of ischial pressure sores. Methods We retrospectively analyzed data from 14 patients (16 ischial sores) whose ischial defects had been reconstructed using both a profunda femoris artery perforator flap and a muscle flap between January 2006 and February 2014. We compared patient characteristics, operative procedure, and clinical course. Results All flaps survived the entire follow-up period. Seven patients (50%) had a history of surgery at the site of the ischial pressure sore. The mean age of the patients included was 52.8 years (range, 18-85 years). The mean follow-up period was 27.9 months (range, 3-57 months). In two patients, a biceps femoris muscle flap was used, while a gracilis muscle flap was used in the remaining patients. In four cases (25%), wound dehiscence occurred, but healed without further complication after resuturing. Additionally, congestion occurred in one case (6%), but resolved with conservative treatment. Among 16 cases, there was only one (6%) recurrence at 34 months. Conclusions The combination of a profunda femoris artery perforator fasciocutaneous flap and muscle flap for the treatment of ischial pressure sores provided pliability, adequate bulkiness and few long-term complications. Therefore, this may be used as an alternative treatment method for ischial pressure sores. PMID:25075362

  14. Enhancement with varying phosphate types, concentrations, and pump rates, without sodium chloride on beef biceps femoris quality and sensory characteristics.

    PubMed

    Baublits, R T; Pohlman, F W; Brown, A H; Johnson, Z B

    2006-03-01

    Beef biceps femoris muscles (n=45) were used to evaluate the effect of enhancement with solutions containing sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP), or tetrasodium pyrophosphate (TSPP) at either 0.2% or 0.4% of product weight, without sodium chloride. All solutions were injected into muscle samples at either 112% (12% pump) or 118% (18% pump) of raw product weight. Muscles enhanced with STPP or TSPP had a higher (P<0.05) pH than SHMP or untreated muscles (CNT), whereas there was no difference (P>0.05) in pH between SHMP and CNT. Muscles enhanced with STPP had less (P<0.05) free water than CNT, whereas SHMP and TSPP did not differ from CNT. However, direct comparison of phosphate types revealed no difference (P>0.05) in free water. Steaks enhanced with SHMP had greater (P<0.05) cooking losses than CNT, whereas steaks treated with STPP or TSPP did not differ (P>0.05) from CNT. Phosphate inclusion at 0.2% allowed for greater (P<0.05) cooking losses than CNT, whereas 0.4% phosphate inclusion exhibited similar (P>0.05) cooking losses as CNT. Although there were no differences (P>0.05) in cooking loss between pump rates, steaks enhanced at an 18% pump rate had greater (P<0.05) cooking losses than CNT, whereas those enhanced at 12% had similar (P>0.05) cooking losses as CNT. Enhancement with any of the three phosphate types or either concentration did not improve (P>0.05) sensory tenderness or juiciness characteristics compared to CNT, but enhancement at an 18% pump rate allowed for improved (P<0.05) overall tenderness, compared to a 12% pump rate. These results suggest that while phosphate enhancement independent of sodium chloride generally did not improve water retention, cooked yields and palatability compared to untreated samples, utilizing higher phosphate concentrations or utilizing STPP or TSPP effectively retained the additional water associated with solution enhancement, allowing for similar free water and cook yields as untreated

  15. Color stability of semitendinosus, semimembranosus, and biceps femoris steaks packaged in a high-oxygen modified atmosphere.

    PubMed

    Behrends, J M; Mikel, W B; Armstrong, C L; Newman, M C

    2003-09-01

    The objectives of this study were to evaluate visual and chemical attributes of beefsteaks from various USDA quality grades and muscles packaged in high-oxygen (80% O2/20% CO2) modified-atmosphere packaging (MAP). A total of nine carcasses were selected to represent Select (n = 3), low Choice (n = 3), and high Choice (n = 3) USDA quality grades. The semimembranosus (SM), semitendinosus (ST), and biceps femoris (BF) muscles were removed from each carcass and allotted to two packaging types (MAP or polyvinyl chloride over-wrap) and were displayed for up to 10 d, with evaluation on d 1, 3, 5, 7, and 10. Fifty-four steaks were evaluated on each day by a five-member trained panel for visual color (lean color and discoloration) and were also analyzed with a Minolta Chroma Meter CR-310 for L* and a* values (lightness and redness, respectively). Chemical properties measured included percentage of metmyoglobin formation and fat content. Visual color scores did not differ (P > 0.05) at d 1 and 3 with respect to all quality grades, but decreased after d 3, with a greater reduction (P < 0.05) in high Choice steaks for both lean color and discoloration. The low Choice steaks packaged in MAP displayedhigher (P < 0.05) lean color scores and less (P < 0.05) discoloration at d 7 and 10 than did Select and high Choice steaks. Redness (a*) values also decreased (P < 0.05) after d 3, whereas (lightness) L* values declined (P < 0.05) from d 1 to 5. The high Choice steaks had higher (P < 0.05) metmyoglobin content than low Choice and Select steaks, but packaging had no effect (P > 0.05) on metmyoglobin content. Muscle type did affect metmyoglobin content; however, the metmyoglobin content of the SM was greatest (P < 0.05), followed by the BF, with the ST having the lowest (P < 0.05) metmyoglobin formation. Results indicate that low Choice steaks react the best in MAP, and the ST maintained greater storage characteristics regardless of quality grade or packaging.

  16. A Comparison of Gluteus Maximus, Biceps Femoris, and Vastus Lateralis Electromyography Amplitude in the Parallel, Full, and Front Squat Variations in Resistance-Trained Females.

    PubMed

    Contreras, Bret; Vigotsky, Andrew D; Schoenfeld, Brad J; Beardsley, Chris; Cronin, John

    2016-02-01

    Front, full, and parallel squats are some of the most popular squat variations. The purpose of this investigation was to compare mean and peak electromyography (EMG) amplitude of the upper gluteus maximus, lower gluteus maximus, biceps femoris, and vastus lateralis of front, full, and parallel squats. Thirteen healthy women (age = 28.9 ± 5.1 y; height = 164 ± 6.3 cm; body mass = 58.2 ± 6.4 kg) performed 10 repetitions of their estimated 10-repetition maximum of each respective variation. There were no statistical (P ≤ .05) differences between full, front, and parallel squats in any of the tested muscles. Given these findings, it can be concluded that the front, full, or parallel squat can be performed for similar EMG amplitudes. However, given the results of previous research, it is recommended that individuals use a full range of motion when squatting, assuming full range can be safely achieved, to promote more favorable training adaptations. Furthermore, despite requiring lighter loads, the front squat may provide a similar training stimulus to the back squat.

  17. A Comparison of Gluteus Maximus, Biceps Femoris, and Vastus Lateralis Electromyographic Activity in the Back Squat and Barbell Hip Thrust Exercises.

    PubMed

    Contreras, Bret; Vigotsky, Andrew D; Schoenfeld, Brad J; Beardsley, Chris; Cronin, John

    2015-12-01

    The back squat and barbell hip thrust are both popular exercises used to target the lower body musculature; however, these exercises have yet to be compared. Therefore, the purpose of this study was to compare the surface electromyographic (EMG) activity of the upper and lower gluteus maximus, biceps femoris, and vastus lateralis between the back squat and barbell hip thrust. Thirteen trained women (n = 13; age = 28.9 years; height = 164 cm; mass = 58.2 kg) performed estimated 10-repetition maximums (RM) in the back squat and barbell hip thrust. The barbell hip thrust elicited significantly greater mean (69.5% vs 29.4%) and peak (172% vs 84.9%) upper gluteus maximus, mean (86.8% vs 45.4%) and peak (216% vs 130%) lower gluteus maximus, and mean (40.8% vs 14.9%) and peak (86.9% vs 37.5%) biceps femoris EMG activity than the back squat. There were no significant differences in mean (99.5% vs 110%) or peak (216% vs 244%) vastus lateralis EMG activity. The barbell hip thrust activates the gluteus maximus and biceps femoris to a greater degree than the back squat when using estimated 10RM loads. Longitudinal training studies are needed to determine if this enhanced activation correlates with increased strength, hypertrophy, and performance.

  18. Regional neuromuscular regulation within human rectus femoris muscle during gait.

    PubMed

    Watanabe, Kohei; Kouzaki, Motoki; Moritani, Toshio

    2014-11-01

    The spatial distribution pattern of neuromuscular activation within the human rectus femoris (RF) muscle was investigated during gait by multi-channel surface electromyography (surface EMG). Eleven healthy men walked on a treadmill with three gait speeds (4, 5, and 6 km/h) and gradients (0°, 12.5°, and 25°). The spatial distribution of surface EMG was tested by central locus activation (CLA), which is calculated from 2-D multi-channel surface EMG with 46 surface electrodes. For all conditions, CLA was around the middle regions during the swing-to-stance transition and moved in a proximal direction during the stance phase and stance-to-swing transition (p<0.05). CLA during the stance-to-swing transition and early swing phase significantly moved to proximal site with increasing gait speed (p<0.05). During the early stance and swing phases, with increasing grade, CLA significantly moved distally (p<0.05). These results suggest that the RF muscle is regionally activated during a gait cycle and is non-uniformly regulated longitudinally.

  19. Effects of enhancement with varying phosphate types and concentrations, at two different pump rates on beef biceps femoris instrumental color characteristics.

    PubMed

    Baublits, R T; Pohlman, F W; Brown, A H; Johnson, Z B

    2005-10-01

    The effect of enhancing beef biceps femoris muscles (n=45) with solutions comprising 2.0% sodium chloride and either sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP), or tetrasodium pyrophosphate (TSPP) at either 0.2% or 0.4% of product weight on instrumental color during simulated retail display was investigated. All solutions were injected into muscle samples at either 112% (12% pump) or 118% (18% pump) of raw product weight. Muscles treated with all three phosphate types had lower (P<0.05) L* and b* values compared to untreated muscles (CNT). Steaks enhanced with STPP had similar (P>0.05) a* values as CNT, whereas SHMP- and TSPP-treated steaks generally had lower a* values than CNT. Across phosphate type, excluding day 3 of display, steaks treated with phosphate at 0.4% had similar (P>0.05) a* values as CNT, whereas those with 0.2% phosphate addition had lower (P<0.05) a* values than CNT. Across five days of display, STPP maintained higher (P<0.05) a* values than steaks treated only with sodium chloride, whereas SHMP did not differ (P>0.05) from sodium chloride-treated steaks. While STPP maintained a similar (P>0.05) saturation index as CNT, SHMP and TSPP generally had decreased (P<0.05) vividness during display. Additionally, excluding day 3 of display, phosphate concentration at 0.4% maintained similar vividness as CNT, whereas 0.2% phosphate concentration caused decreased (P<0.05) vividness, compared to CNT. The 630/580nm ratio results indicated that SHMP had less (P<0.05) oxymyoglobin than CNT throughout display. Disregarding day 3 of display, both STPP and TSPP had similar (P>0.05) oxymyoglobin proportions as CNT. These results indicate that STPP was the most effective phosphate type for maintaining color. Additionally, 0.4% phosphate concentrations can maintain color better than 0.2% phosphate concentrations. However, none of the phosphate/salt combinations produced superior color, compared to untreated steaks.

  20. 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.

  1. Giant pseudocyst of the rectus femoris muscle--repetitive strain injury in recreational soccer player.

    PubMed

    Cicvarić, Tedi; Lucin, Ksenija; Roth, Sandor; Ivancić, Aldo; Marinović, Marin; Santić, Veljko

    2010-04-01

    We report a case of a traumatic pseudocyst, in a recreational soccer player, after rupture of rectus femoris muscle. 37-year-old male, with history of repetitive painful accidents, was examined because of a double fist-sized mass in the anterior thigh. Ultrasound examination revealed a cystic mass in the rectus femoris muscle. Surgical removal of the mass and proximal remnant of muscle was done. Primary healing and functional recovery was achieved. Histological analysis revealed pseudocyst filled with degenerating clot and surrounded with thick fibrous capsule. The repetitive strain muscle injury, with prolonged period of healing, can occur like pseudocyst.

  2. Effects of enhancement with differing phosphate types, concentrations, and pump rates, without sodium chloride, on beef biceps femoris instrumental color characteristics.

    PubMed

    Baublits, R T; Pohlman, F W; Brown, A H; Johnson, Z B

    2006-03-01

    Enhancement of beef biceps femoris muscles (n=45) with solutions comprising sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP), or tetrasodium pyrophosphate (TSPP) at either 0.2% or 0.4% of product weight, with the exclusion of sodium chloride, was performed to observe the independent phosphate effects on instrumental color during simulated retail display. All solutions were injected into muscle samples at either 112% (12% pump) or 118% (18% pump) of raw product weight. All three phosphate types maintained higher (P<0.05) L* values than untreated steaks (CNT) through 5 days-of-display, and SHMP had higher (P<0.05) L* values than STPP and TSPP through 7 days-of-display. Additionally, steaks with 0.2% phosphate inclusion were lighter (L*; P<0.05) than CNT throughout display, and were lighter (P<0.05) than steaks enhanced with 0.4% phosphates through 7 days of display. Steaks enhanced with TSPP had higher (P<0.05) a* values than CNT on days 5 and 7 of display, whereas SHMP- or STPP-enhanced steaks generally had similar (P>0.05) a* values as CNT after 3d of display. Direct comparison of phosphate concentrations revealed no differences (P>0.05) in a* values. Only steaks enhanced with TSPP were more vivid (P<0.05) and had higher (P<0.05) proportions of oxymyoglobin than CNT on days 5 and 7 of display. However, direct comparison of phosphate types indicated that TSPP- and STPP-enhanced steaks had similar (P>0.05) oxymyoglobin proportions during display. Phosphate inclusion at 0.4% maintained higher (P<0.05) oxymyoglobin proportions than 0.2% phosphate inclusion through 5 days-of-display. These results indicate that while 0.2% phosphate concentrations maintain lighter color, 0.4% concentrations can more effectively retain oxymyoglobin during display. Additionally, only steaks enhanced with TSPP were redder, more vivid, and had higher oxymyoglobin proportions than untreated steaks during the latter stages of display.

  3. Electromyographic biofeedback and recovery of quadriceps femoris muscle function following anterior cruciate ligament reconstruction.

    PubMed

    Draper, V

    1990-01-01

    The purpose of this study was to compare the effects of biofeedback-facilitated exercise with exercise alone on the recovery rate of quadriceps femoris muscle function following anterior cruciate ligament (ACL) reconstruction. Functional measures included 1) a dynamometric test of quadriceps femoris muscle isometric peak torque during the 12th postoperative week and 2) the number of days post-operatively that a patient achieved full active extension of the knee. Twenty-two patients with acute ACL injury were randomly assigned to a Treatment (biofeedback) Group (n = 11) or a Control (nonfeedback) Group (n = 11) during the first therapy session one week after reconstructive surgery. After the patients had completed the 12-week exercise program, the quadriceps femoris muscle isometric peak torque in the operative limb was compared with that in the nonoperative limb at three angles (90 degrees, 60 degrees, and 45 degrees) of extension. An analysis of variance revealed significant differences between the Treatment and Control Groups at all three angles. Mean recovery time was calculated for each group, and a t test for independent samples indicated a significant difference between the groups. These results demonstrate that the addition of biofeedback to muscle strengthening exercises facilitates the rate of recovery of quadriceps femoris muscle function following ACL reconstruction.

  4. Force enhancement during and following muscle stretch of maximal voluntarily activated human quadriceps femoris.

    PubMed

    Hahn, Daniel; Seiberl, Wolfgang; Schwirtz, Ansgar

    2007-08-01

    Force enhancement during and following muscle stretch has been observed for electrically and voluntarily activated human muscle. However, especially for voluntary contractions, the latter observation has only been made for adductor pollicis and the ankle joint muscles, but not for large muscles like quadriceps femoris. Therefore, the aim of this study was to investigate the effects of active muscle stretch on force production for maximal voluntary contractions of in vivo human quadriceps femoris (n = 15). Peak torques during and torques at the end of stretch, torques following stretch, and passive torques following muscle deactivation were compared to the isometric torques at corresponding muscle length. In addition, muscle activation of rectus femoris, vastus medialis and vastus lateralis was obtained using surface EMG. Stretches with different amplitudes (15, 25 and 35 degrees at a velocity of 60 degrees s(-1)) were performed on the plateau region and the descending limb of the force-length relation in a random order. Data analysis showed four main results: (1) peak torques did not occur at the end of the stretch, but torques at the end of the stretch exceeded the corresponding isometric torque; (2) there was no significant force enhancement following muscle stretch, but a small significant passive force enhancement persisted for all stretch conditions; (3) forces during and following stretch were independent of stretch amplitude; (4) muscle activation during and following muscle stretch was significantly reduced. In conclusion, although our results showed passive force enhancement, we could not provide direct evidence that there is active force enhancement in voluntarily activated human quadriceps femoris.

  5. Mechanism of quadriceps femoris muscle weakness in patients with anterior cruciate ligament reconstruction.

    PubMed

    Konishi, Y; Fukubayashi, T; Takeshita, D

    2002-12-01

    The purpose of this study was to investigate gamma loop function in the quadriceps femoris muscle in patients who with less than 6 month-history of anterior cruciate ligament (ACL) reconstruction. For this purpose, we compared the response to vibration stimulation in 10 patients with ACL repair and 12 normal healthy subjects, by measuring the maximal voluntary isometric contraction (MVC) and integrated electromyograms (I-EMG) of the quadriceps muscles. Pre-vibration data were obtained from each subject by measuring the MVC of the knee extension and the I-EMG from the vastus medialis, vastus lateralis, and rectus femoris muscles. Vibration stimulation was applied to the infrapatellar tendons, followed immediately by repeating the MVC and I-EMG recording. Prolonged vibration resulted in a significant decrease of both MVC and I-EMG in the control group. In contrast, the same stimulus failed to elicit changes in ACL-repair group. Our results suggest the presence of abnormal gamma loop function in the quadriceps femoris muscle of patients with ACL repair, which may explain the muscle weakness often described in such patients.

  6. Relationship between quadriceps femoris muscle volume and muscle torque after anterior cruciate ligament repair.

    PubMed

    Konishi, Y; Ikeda, K; Nishino, A; Sunaga, M; Aihara, Y; Fukubayashi, T

    2007-12-01

    This study was performed to obtain evidence regarding bilateral hindrance of motor unit (MU) recruitment in the quadriceps femoris (QF) of patients with anterior cruciate ligament (ACL) reconstruction. The subjects included 70 patients who underwent ACL reconstruction and 35 healthy subjects. To identify the muscle torque per unit volume (MTPUV), the peak torque of each velocity of isokinetic performance was divided by muscle volume of the QF measured by a series of cross-sectional images obtained by magnetic resonance imaging scans. Tests revealed that the mean MTPUV of the uninjured (0.113+/-0.03 N m/cm3 at 60 degrees /s, 0.081+/-0.02 N m/cm3 at 180 degrees /s) and injured sides (0.109+/-0.03 N m/cm3 at 60 degrees /s, 0.079+/-0.023 N m/cm3 at 180 degrees /s) were significantly lower than those of the control group (0.144+/-0.05 N m/cm3 at 60 degrees /s, 0.096+/-0.04 N m/cm3 at 180 degrees /s). Previous studies suggested that MU recruitment in the QF of patients with ACL injury was hindered bilaterally. However, the design of their studies could not provide evidence of bilateral hindrance of MU recruitment in the QF. The results of the present study demonstrated that the MTPUV of both injured and uninjured sides of patients were significantly lower than those of the control group.

  7. A Comparison of Gluteus Maximus, Biceps Femoris, and Vastus Lateralis Electromyography Amplitude for the Barbell, Band, and American Hip Thrust Variations.

    PubMed

    Contreras, Bret; Vigotsky, Andrew D; Schoenfeld, Brad J; Beardsley, Chris; Cronin, John

    2016-06-01

    Bridging exercise variations are well researched and commonly employed for both rehabilitation and sport performance. However, resisted bridge exercise variations have not yet been compared in a controlled experimental study. Therefore, the purpose of this study was to compare the differences in upper and lower gluteus maximus, biceps femoris, and vastus lateralis electromyography (EMG) amplitude for the barbell, band, and American hip thrust variations. Thirteen healthy female subjects (age = 28.9 y; height = 164.3 cm; body mass = 58.2 kg) familiar with the hip thrust performed 10 repetitions of their 10-repetition maximum of each variation in a counterbalanced and randomized order. The barbell hip thrust variation elicited statistically greater mean gluteus maximus EMG amplitude than the American and band hip thrusts, and statistically greater peak gluteus maximus EMG amplitude than the band hip thrust (P ≤ .05), but no other statistical differences were observed. It is recommended that resisted bridging exercise be prescribed according to the individual's preferences and desired outcomes.

  8. Measurement of the quadriceps femoris muscle using magnetic resonance and ultrasound imaging.

    PubMed Central

    Walton, J M; Roberts, N; Whitehouse, G H

    1997-01-01

    OBJECTIVES: To define a method for measurement of the cross sectional area and volume of the quadriceps femoris muscle using magnetic resonance imaging (MRI) in conjunction with stereology, and to compare the results of measurements obtained by the MRI method with those obtained by the conventional method of static B-mode ultrasound in order to evaluate whether MRI is a reliable alternative to ultrasound. METHODS: A preliminary MRI study was undertaken on a single female volunteer in order to optimise the scanning technique and sampling design for estimating the muscle volume using the Cavalieri method. Ten healthy volunteers participated in the method comparison study. Each volunteer underwent static B-mode ultrasonography, immediately followed by MRI. The cross sectional area of the quadriceps femoris was estimated at the junction of the proximal one third and distal two thirds of the thigh, and seven systematic sections of the thigh were obtained in order to estimate muscle volume by both modalities. RESULTS: Seven sections through the muscle are required to achieve a coefficient of error of 4-5%. There was no significant difference in the cross sectional area estimates or volume estimates when ultrasound and MRI were compared. CONCLUSION: Muscle cross sectional area and volume can be measured without bias by MRI in conjunction with stereological methods and the method is a reliable alternative to static B-mode ultrasound for this purpose. Images Figure 1 Figure 4 Figure 5 PMID:9132215

  9. Effect of experimental muscle pain on maximal voluntary activation of human biceps brachii muscle.

    PubMed

    Khan, Serajul I; McNeil, Chris J; Gandevia, Simon C; Taylor, Janet L

    2011-09-01

    Muscle pain has widespread effects on motor performance, but the effect of pain on voluntary activation, which is the level of neural drive to contracting muscle, is not known. To determine whether induced muscle pain reduces voluntary activation during maximal voluntary contractions, voluntary activation of elbow flexors was assessed with both motor-point stimulation and transcranial magnetic stimulation over the motor cortex. In addition, we performed a psychophysical experiment to investigate the effect of induced muscle pain across a wide range of submaximal efforts (5-75% maximum). In all studies, elbow flexion torque was recorded before, during, and after experimental muscle pain by injection of 1 ml of 5% hypertonic saline into biceps. Injection of hypertonic saline evoked deep pain in the muscle (pain rating ∼5 on a scale from 0 to 10). Experimental muscle pain caused a small (∼5%) but significant reduction of maximal voluntary torque in the motor-point and motor cortical studies (P < 0.001 and P = 0.045, respectively; n = 7). By contrast, experimental muscle pain had no significant effect on voluntary activation when assessed with motor-point and motor cortical stimulation although voluntary activation tested with motor-point stimulation was reduced by ∼2% in contractions after pain had resolved (P = 0.003). Furthermore, induced muscle pain had no significant effect on torque output during submaximal efforts (P > 0.05; n = 6), which suggests that muscle pain did not alter the relationship between the sense of effort and production of voluntary torque. Hence, the present study suggests that transient experimental muscle pain in biceps brachii has a limited effect on central motor pathways. PMID:21737829

  10. Angle- and gender-specific quadriceps femoris muscle recruitment and knee extensor torque.

    PubMed

    Pincivero, Danny M; Salfetnikov, Yuliya; Campy, Robert M; Coelho, Alan J

    2004-11-01

    The objectives were to examine knee angle-, and gender-specific knee extensor torque output and quadriceps femoris (QF) muscle recruitment during maximal effort, voluntary contractions. Fourteen young adult men and 15 young adult women performed three isometric maximal voluntary contractions (MVC), in a random order, with the knee at 0 degrees (terminal extension), 10 degrees, 30 degrees, 50 degrees, 70 degrees, and 90 degrees flexion. Knee extensor peak torque (PT), and average torque (AT) were expressed in absolute (N m), relative (N m kg(-1)) and allometric-modeled (N m kg(-n)) units. Vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscle EMG signals were full-wave rectified and integrated over the middle 3 s of each contraction, averaged over the three trials at each knee angle, and normalized to the activity recorded at 0 degrees. Muscle recruitment efficiency was calculated as the ratio of the normalized EMG of each muscle to the allometric-modeled average torque (normalized to the values at 0 degrees flexion), and expressed as a percent. Men generated significantly greater knee extensor PT and AT than women in absolute, relative and allometric-modeled units. Absolute and relative PT and AT were significantly highest at 70 degrees, while allometric-modeled values were observed to increase significantly across knee joint angles 10-90 degrees. VM EMG was significantly greater than the VL and RF muscles across all angles, and followed a similar pattern to absolute knee extensor torque. Recruitment efficiency improved across knee joint angles 10-90 degrees and was highest for the VL muscle. VM recruitment efficiency improved more than the VL and RF muscles across 70-90 degrees flexion. The findings demonstrate angle-, and gender-specific responses of knee extensor torque to maximal-effort contractions, while superficial QF muscle recruitment was most efficient at 90 degrees, and less dependent on gender.

  11. Relationship between quadriceps femoris echo intensity, muscle power, and functional capacity of older men.

    PubMed

    Wilhelm, Eurico Nestor; Rech, Anderson; Minozzo, Felipe; Radaelli, Regis; Botton, Cíntia Ehlers; Pinto, Ronei Silveira

    2014-06-01

    Increased proportion of non-contractile elements can be observed during aging by enhanced skeletal muscle echo intensity (EI). Studies have demonstrated that an increase in rectus femoris EI may affect physical performance. However, it is still unknown whether the whole quadriceps femoris EI (QEI) influences strength, power, and functional capacity of an older population. Therefore, the aim of the present study was to determine the correlation between QEI, the four individual quadriceps portions EI, and muscular performance of older men. Fifty sedentary healthy men (66.1 ± 4.5 years, 1.75 ± 0.06 m, 80.2 ± 11.0 kg) volunteered for the present study. The QEI and EI of the four quadriceps portions were calculated by ultrasound imaging. Knee extension one repetition maximum (1RM), isometric peak torque (PT), and rate of torque development (RTD) were obtained as measures of muscular strength. Muscular power was determined by knee extension with 60 % of 1RM and countermovement jump (CMJ). The 30-s sit-to-stand test was evaluated as a functional capacity parameter. QEI and all individual EI were correlated to functional capacity and power during CMJ (p ≤ 0.05), but rectus femoris EI was not related to knee extension average power (p > 0.05). There were significant correlations between all EI variables, 1RM, PT, and RTD at 0.2 s (p ≤ 0.05), but only vastus medialis EI and QEI were correlated to RTD at 0.05 s (p ≤ 0.05). The results of the present study suggest that QEI is related to muscular power and functional capacity of older subjects, but the EI of some individual quadriceps portions may underestimate the correlations with muscular performance.

  12. Morphology and clinical implication of the extra-head of biceps brachii muscle.

    PubMed

    Nasr, Ashraf Y; Hussein, Adel M

    2013-11-01

    The biceps brachii muscle is present in the anterior aspect of the arm. Its morphological variations have great clinical significance for surgeons, orthopaedic surgeons, anaesthetists, neurologists and anatomists. This study aimed to describe the incidence and morphology of the extra-heads of the biceps brachii muscle. Hundred upper limbs of 50 adult human cadavers (30 men and 20 women) were used in this study after the approval of the medical ethical committee. These cadavers were obtained from the Anatomy Department, Faculty of Medicine, King Abdul-Aziz University. The incidence of anatomical variations of biceps muscle was equal in both male and female cadavers (10%) with predominance of the left side (7%). The 3-headed biceps brachii muscle was noticed in 7% (4% male and 3% female), while the 4-headed biceps was seen in 2 (2%) left limbs, 1 male and 1 female. The third head of the biceps muscle arose from the anteromedial aspect of humerus, between the coracobrachialis insertion and the brachialis origin, in 6% and from middle of the medial border of humerus in 3%. While the fourth head originated from the articular capsule of shoulder joint in 1 (1%) limb and from the coracoid process of scapula in the other limb. The biceps common tendon of insertion received the supernumerary heads in 7% of the limbs. However, the extra-head fused with the long head in 2 (2%) limbs and united with the short head in 1 (1%) limb. The mean of the third head length was 118.8±10.9 in all limbs, where it was 121.8±12.3 in male and 113.5±8.1 in female cadavers. The third head length/arm length ratio was 38.4±2.6 in all, 38.3±3.4 in male and 38.8±1.8 in female cadavers. The length of the extra-head was extremely significant with those of the corresponding limb in all, male and female cadavers (p<0.0001). Knowledge of the morphological variations of biceps muscle provides better pre-operative evaluation, safe surgical intervention within the arm and better postoperative

  13. Analysis of three different equations for predicting quadriceps femoris muscle strength in patients with COPD *

    PubMed Central

    Nellessen, Aline Gonçalves; Donária, Leila; Hernandes, Nidia Aparecida; Pitta, Fabio

    2015-01-01

    Abstract Objective: To compare equations for predicting peak quadriceps femoris (QF) muscle force; to determine the agreement among the equations in identifying QF muscle weakness in COPD patients; and to assess the differences in characteristics among the groups of patients classified as having or not having QF muscle weakness by each equation. Methods: Fifty-six COPD patients underwent assessment of peak QF muscle force by dynamometry (maximal voluntary isometric contraction of knee extension). Predicted values were calculated with three equations: an age-height-weight-gender equation (Eq-AHWG); an age-weight-gender equation (Eq-AWG); and an age-fat-free mass-gender equation (Eq-AFFMG). Results: Comparison of the percentage of predicted values obtained with the three equations showed that the Eq-AHWG gave higher values than did the Eq-AWG and Eq-AFFMG, with no difference between the last two. The Eq-AHWG showed moderate agreement with the Eq-AWG and Eq-AFFMG, whereas the last two also showed moderate, albeit lower, agreement with each other. In the sample as a whole, QF muscle weakness (< 80% of predicted) was identified by the Eq-AHWG, Eq-AWG, and Eq-AFFMG in 59%, 68%, and 70% of the patients, respectively (p > 0.05). Age, fat-free mass, and body mass index are characteristics that differentiate between patients with and without QF muscle weakness. Conclusions: The three equations were statistically equivalent in classifying COPD patients as having or not having QF muscle weakness. However, the Eq-AHWG gave higher peak force values than did the Eq-AWG and the Eq-AFFMG, as well as showing greater agreement with the other equations. PMID:26398750

  14. Mechanics of the muscles crossing the hip joint during sprint running.

    PubMed

    Nagano, Yasuharu; Higashihara, Ayako; Takahashi, Kazumasa; Fukubayashi, Toru

    2014-01-01

    We aimed to demonstrate the changes over time in the lengths and forces of the muscles crossing the hip joint during overground sprinting and investigate the relationships between muscle lengths and muscle-tendon unit forces - particularly peak biceps femoris force. We obtained three-dimensional kinematics during 1 running cycle from 8 healthy sprinters sprinting at maximum speed. Muscle lengths and muscle-tendon unit forces were calculated for the iliacus, rectus femoris, gluteus maximus, and biceps femoris muscles of the target leg as well as the contralateral iliacus and rectus femoris. Our results showed that during sprinting, the muscles crossing the hip joint demonstrate a stretch-shortening cycle and 1 or 2 peak forces. The timing of peak biceps femoris force, expressed as a percentage of the running cycle (mean [SD], 80.5 [2.9]%), was synchronous with those of the maximum biceps femoris length (82.8 [1.9]%) and peak forces of the gluteus maximus (83.8 [9.1]%), iliacus (81.1 [5.2]%), and contralateral iliacus (78.5 [5.8]%) and also that of the peak pelvic anterior tilt. The force of the biceps femoris appeared to be influenced by the actions of the muscles crossing the hip joint as well as by the pelvic anterior tilt.

  15. Regional neuromuscular regulation within human rectus femoris muscle during gait in young and elderly men.

    PubMed

    Watanabe, Kohei; Kouzaki, Motoki; Moritani, Toshio

    2016-01-01

    Recently, we demonstrated region-specific electromyography (EMG) responses along the rectus femoris (RF) muscle during gait in healthy young men (Watanabe et al., 2014b). For the RF muscle, regional EMG response should be tested to characterize neuromuscular control and/or to assess its dysfunction and/or pathology during gait. We aimed to identify spatial distribution of EMG pattern within the RF muscle in elderly during gait. Seven young men (age: 20.4±1.0 years) and 8 elderly men (age: 73.8±5.9 years) walked on treadmill with three different speed: slow (preferred -1km/h), preferred, and fast (preferred +1km/h). The spatial distribution of surface EMG was tested by central locus activation (CLA), which is calculated from 18 surface electrodes along the longitudinal line of the muscle. CLA were not different between the groups for slow and preferred gait speed (p>0.05) during a gait cycle. In fast gait speed, CLA at 80% of a gait cycle (swing phase) for the elderly were significantly located at more distal site than the young group (p<0.05) (13.0±2.1cm and 10.2±2.2cm from most proximal electrodes for the elderly and young). This difference in CLA reflected a significantly lower EMG activity at the proximal regions in the elderly group (p<0.05). These results suggest the elderly manifest characteristic regional EMG responses within the RF muscle for leg swing movement of fast speed gait.

  16. Assessment of the Quadriceps Femoris Muscle in Women after Injury Induced by Maximal Eccentric Isokinetic Exercise with Low Angular Speed

    PubMed Central

    Serráo, Fábio Viadanna; Serráo, Paula Regina Mendes da Silva; Foerster, Bernd; Tannús, Alberto; Monteiro Pedro, Vanessa; Salvini, Tania F.

    2007-01-01

    The objectives of this study were to propose a model for exercise- induced muscle injury by way of a maximal eccentric isokinetic exercise at low angular speed, and assess the time course of functional recovery of the injured quadriceps femoris muscle from the maximal voluntary contraction (MVC) torque and electrical activity (root mean square - RMS and median frequency - MDF). The effectiveness of the proposed eccentric exercise in inducing injury was assessed from the activity of creatine kinase (CK). In addition, the presence of edema of the quadriceps femoris muscle was assessed by a visual inspection of the intensity of the magnetic resonance imaging (MRI) signal. These measurements were carried out before and after the exercise. Ten healthy women (21.9 ± 1.5) took part in this study. The injury was induced by 4 series of 15 maximal eccentric isokinetic contractions at 5°/s. The MVC torque reduced up to the 4th day after the exercise (p < 0.05). The RMS of the vastus medialis oblique (VMO) and the rectus femoris (RF) muscles decreased on the 2nd (VMO and RF; p < 0.05) and 3rd (RF; p < 0.05) days after. The MDF of the VMO increased immediately after (p < 0.05), whilst the MDF of the RF and VL decreased immediately after (RF; p < 0.05), on the 1st (RF and VL; p < 0.05) and on the 2nd (VL; p < 0.05) days after. The CK activity increased on the 2nd day after (p < 0.05). An increase in the intensity of the MRI signal was observed on the 2nd and 7th days after. In conclusion: 1- the eccentric exercise with low angular speed was effective in inducing injury, 2- the quadriceps femoris already started its functional recovery, as shown by the MVC torque and electrical activity, in the first week after the exercise, despite the presence of an increase in the intensity of the MRI signal. Key pointsThe low angular speed eccentric exercise was effec-tive in inducing injury of the quadriceps femoris muscle, and could be used as a muscle injury induc-ing model in future

  17. Relationship between quadriceps femoris muscle volume and muscle torque at least 18 months after anterior cruciate ligament reconstruction.

    PubMed

    Konishi, Y; Oda, T; Tsukazaki, S; Kinugasa, R; Fukubayashi, T

    2012-12-01

    The purpose of this study was to evaluate motor unit recruitment in the quadriceps femoris (QF) after anterior cruciate ligament (ACL) rupture and repair. Subjects included 24 patients at ≥ 18 months after ACL reconstruction and 22 control subjects with no history of knee injury. A series of cross-sectional magnetic resonance images were obtained to compare the QF of patients' injured side with that of their uninjured sides and that of uninjured control subjects. Muscle torque per muscle volume was calculated as isokinetic peak torque divided by QF muscle volume (cm(3)). The mean muscle torque per unit volume of the injured side of patients was not significantly different from that of the uninjured side or control subjects (one-way ANOVA) Results of the present study were contrary to the results of a previous study that evaluated patients at ≤ 12 months after ACL reconstruction. The present study found that high-threshold motor unit recruitment was restored at ≥ 18 months after ACL reconstruction. Thus, clinicians must develop techniques that increase the recruitment of high-threshold motor units in the QF from the period immediately after the injury until approximately 18 months after ACL reconstruction.

  18. Effect of eccentric exercise with reduced muscle glycogen on plasma interleukin-6 and neuromuscular responses of musculus quadriceps femoris.

    PubMed

    Gavin, James P; Myers, Stephen D; Willems, Mark E T

    2016-07-01

    Eccentric exercise can result in muscle damage and interleukin-6 (IL-6) secretion. Glycogen availability is a potent stimulator of IL-6 secretion. We examined effects of eccentric exercise in a low-glycogen state on neuromuscular function and plasma IL-6 secretion. Twelve active men (23 ± 4 yr, 179 ± 5 cm, 77 ± 10 kg, means ± SD) completed two downhill treadmill runs (gradient, -12%, 5 × 8 min; speed, 12.1 ± 1.1 km/h) with normal (NG) and reduced muscle glycogen (RG) in randomized order and at least 6 wk apart. Muscle glycogen was reduced using an established cycling protocol until exhaustion and dietary manipulation the evening before the morning run. Physiological responses were measured up to 48 h after the downhill runs. During recovery, force deficits of musculus quadriceps femoris by maximal isometric contractions were similar. Changes in low-frequency fatigue were larger with RG. Voluntary activation and plasma IL-6 levels were similar in recovery between conditions. It is concluded that unaccustomed, damaging eccentric exercise with low muscle glycogen of the m. quadriceps femoris 1) exacerbated low-frequency fatigue but 2) had no additional effect on IL-6 secretion. Neuromuscular impairment after eccentric exercise with low muscle glycogen appears to have a greater peripheral component in early recovery. PMID:27150832

  19. Effect of eccentric exercise with reduced muscle glycogen on plasma interleukin-6 and neuromuscular responses of musculus quadriceps femoris.

    PubMed

    Gavin, James P; Myers, Stephen D; Willems, Mark E T

    2016-07-01

    Eccentric exercise can result in muscle damage and interleukin-6 (IL-6) secretion. Glycogen availability is a potent stimulator of IL-6 secretion. We examined effects of eccentric exercise in a low-glycogen state on neuromuscular function and plasma IL-6 secretion. Twelve active men (23 ± 4 yr, 179 ± 5 cm, 77 ± 10 kg, means ± SD) completed two downhill treadmill runs (gradient, -12%, 5 × 8 min; speed, 12.1 ± 1.1 km/h) with normal (NG) and reduced muscle glycogen (RG) in randomized order and at least 6 wk apart. Muscle glycogen was reduced using an established cycling protocol until exhaustion and dietary manipulation the evening before the morning run. Physiological responses were measured up to 48 h after the downhill runs. During recovery, force deficits of musculus quadriceps femoris by maximal isometric contractions were similar. Changes in low-frequency fatigue were larger with RG. Voluntary activation and plasma IL-6 levels were similar in recovery between conditions. It is concluded that unaccustomed, damaging eccentric exercise with low muscle glycogen of the m. quadriceps femoris 1) exacerbated low-frequency fatigue but 2) had no additional effect on IL-6 secretion. Neuromuscular impairment after eccentric exercise with low muscle glycogen appears to have a greater peripheral component in early recovery.

  20. Intramuscular variation in fresh ham muscle color

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This experiment was conducted to characterize a defect involving pale muscle tissue in the superficial, ventral portion of ham muscles, resulting in two-toned appearance of cured ham products. Biceps femoris muscles (n = 200), representing 3 production systems, were obtained from the ham-boning lin...

  1. Real-time measurement of rectus femoris muscle kinematics during drop jump using ultrasound imaging: a preliminary study.

    PubMed

    Eranki, Avinash; Cortes, Nelson; Ferencek Gregurić, Zrinka; Kim, John J; Sikdar, Siddhartha

    2012-01-01

    We have developed an office based vector tissue Doppler imaging (vTDI) that can be used to quantitatively measure muscle kinematics using ultrasound. The goal of this preliminary study was to investigate if vTDI measures are repeatable and can be used robustly to measure and understand the kinematics of the rectus femoris muscle during a drop jump task. Data were collected from 8 healthy volunteers. Vector TDI along with a high speed camera video was used to better understand the dynamics of the drop jump. Our results indicate that the peak resultant vector velocity of the rectus femoris immediately following landing was repeatable across trials (intraclass correlation coefficient=0.9).The peak velocity had a relatively narrow range in 6 out of 8 subjects (48-62 cm/s), while in the remaining two subjects it exceeded 70 cm/s. The entire drop jump lasted for 1.45 0.27 seconds. The waveform of muscle velocity could be used to identify different phases of the jump. Also, the movement of the ultrasound transducer holder was minimal with peak deflection of 0.91 0.54 degrees over all trials. Vector TDI can be implemented in a clinical setting using an ultrasound system with a research interface to better understand the muscle kinematics in patients with ACL injuries.

  2. The effects of kinesio taping on architecture, strength and pain of muscles in delayed onset muscle soreness of biceps brachii

    PubMed Central

    Lee, Yong Sin; Bae, Sea Hyun; Hwang, Jin Ah; Kim, Kyung Yoon

    2015-01-01

    [Purpose] This study aimed to confirm the effects of kinesio taping (KT) on muscle function and pain due to delayed onset muscle soreness (DOMS) of the biceps brachii. [Subjects and Methods] Thirty-seven subjects with induced DOMS were randomized into either Group I (control, n=19) or Group II (KT, n=18). Outcome measures were recorded before the intervention (application of KT) and at 24, 48, and 72 hours after the intervention. DOMS was induced, and muscle thickness was measured using ultrasonic radiography. Maximal voluntary isometric contraction (%MVIC) was measured via electromyography (EMG). Subjective pain was measured using a visual analogue scale (VAS). [Results] Group I exhibited a positive correlation between muscle thickness and elapsed time from intervention (24, 48, and 72 hours post induction of DOMS); they also showed a significant decrease in MVIC(%). Group II showed significant increases in muscle thickness up to the 48-hour interval post induction of DOMS, along with a significant decrease in MVIC (%). However, in contrast to Group I, Group II did not show a significant difference in muscle thickness or MVIC (%) at the 72-hour interval in comparison with the values prior to DOMS induction. [Conclusion] In adults with DOMS, activation of muscles by applying KT was found to be an effective and faster method of recovering muscle strength than rest alone. PMID:25729190

  3. The effects of kinesio taping on architecture, strength and pain of muscles in delayed onset muscle soreness of biceps brachii.

    PubMed

    Lee, Yong Sin; Bae, Sea Hyun; Hwang, Jin Ah; Kim, Kyung Yoon

    2015-02-01

    [Purpose] This study aimed to confirm the effects of kinesio taping (KT) on muscle function and pain due to delayed onset muscle soreness (DOMS) of the biceps brachii. [Subjects and Methods] Thirty-seven subjects with induced DOMS were randomized into either Group I (control, n=19) or Group II (KT, n=18). Outcome measures were recorded before the intervention (application of KT) and at 24, 48, and 72 hours after the intervention. DOMS was induced, and muscle thickness was measured using ultrasonic radiography. Maximal voluntary isometric contraction (%MVIC) was measured via electromyography (EMG). Subjective pain was measured using a visual analogue scale (VAS). [Results] Group I exhibited a positive correlation between muscle thickness and elapsed time from intervention (24, 48, and 72 hours post induction of DOMS); they also showed a significant decrease in MVIC(%). Group II showed significant increases in muscle thickness up to the 48-hour interval post induction of DOMS, along with a significant decrease in MVIC (%). However, in contrast to Group I, Group II did not show a significant difference in muscle thickness or MVIC (%) at the 72-hour interval in comparison with the values prior to DOMS induction. [Conclusion] In adults with DOMS, activation of muscles by applying KT was found to be an effective and faster method of recovering muscle strength than rest alone.

  4. Enthesitis of the direct tendon of the rectus femoris muscle in a professional volleyball player: A case report.

    PubMed

    Bortolotto, C; Coscia, D R; Ferrozzi, G

    2011-06-01

    Enthesitis of the direct tendon of the rectus femoris muscle is a rare pathology which mainly affects professional athletes, and it is caused by overuse and repetitive microtrauma. Athletic jumping and kicking exert a great stress on the direct tendon of the rectus femoris muscle, and volleyball and football players are therefore most frequently affected. Enthesitis may occur suddenly causing pain and functional impairment possibly associated with partial or complete tendon injuries, or it may be a chronic condition causing non-specific clinical symptoms.We present the case of a professional volleyball player who felt a sudden pain in the left side of the groin area during a training session although she had suffered no accidental injury. The pain was associated with impaired ipsilateral limb function. Tendon rupture was suspected, and magnetic resonance imaging (MRI) was performed. MRI showed a lesion at the myotendinous junction associated with marked inhomogeneity of the direct tendon. Ultrasound (US) examination confirmed the presence of both lesions and allowed a more detailed study of the pathology.This is a typical case of enthesitis which confirms that MRI should be considered the examination of choice in hip pain, particularly when the patient is a professional athlete, thanks to its panoramic visualization. However, also US is an ideal imaging technique for evaluating tendon injuries thanks to its high spatial resolution, and it can therefore be used effectively as a second line of investigation.

  5. Effects of combined application of progressive resistance training and Russian electrical stimulation on quadriceps femoris muscle strength in elderly women with knee osteoarthritis.

    PubMed

    Park, Seong Hoon; Hwangbo, Gak

    2015-03-01

    [Purpose] The aim of this study was to investigate the effects of combined application of progressive resistance training and Russian electrical stimulation on quadriceps femoris muscle strength in elderly women with osteoarthritis of the knee. [Subjects] Thirty women over 65 years of age diagnosed with knee osteoarthritis participated in the present study. The subjects were randomly assigned to a control group (n=10), a progressive resistance training group (n=10), or a Russian electrical stimulation group (n=10). [Methods] Each group was treated 3 times weekly for 8 weeks, and each session lasted 45 minutes. Muscle strength was assessed by measuring the peak torque of the quadriceps femoris muscle. Outcome measurements were performed at baseline and at the fourth and eighth weeks of the treatment period. [Results] All groups showed significant intragroup differences in the quadriceps femoris muscle peak torque after the treatment intervention. There were significant intergroup differences between the Russian electrical stimulation group and the other groups. [Conclusion] The results of this study suggest that combined application of progressive resistance training and Russian electrical stimulation can be effective in strengthening the quadriceps femoris muscle in elderly women with knee osteoarthritis.

  6. Effects of combined application of progressive resistance training and Russian electrical stimulation on quadriceps femoris muscle strength in elderly women with knee osteoarthritis

    PubMed Central

    Park, Seong Hoon; Hwangbo, Gak

    2015-01-01

    [Purpose] The aim of this study was to investigate the effects of combined application of progressive resistance training and Russian electrical stimulation on quadriceps femoris muscle strength in elderly women with osteoarthritis of the knee. [Subjects] Thirty women over 65 years of age diagnosed with knee osteoarthritis participated in the present study. The subjects were randomly assigned to a control group (n=10), a progressive resistance training group (n=10), or a Russian electrical stimulation group (n=10). [Methods] Each group was treated 3 times weekly for 8 weeks, and each session lasted 45 minutes. Muscle strength was assessed by measuring the peak torque of the quadriceps femoris muscle. Outcome measurements were performed at baseline and at the fourth and eighth weeks of the treatment period. [Results] All groups showed significant intragroup differences in the quadriceps femoris muscle peak torque after the treatment intervention. There were significant intergroup differences between the Russian electrical stimulation group and the other groups. [Conclusion] The results of this study suggest that combined application of progressive resistance training and Russian electrical stimulation can be effective in strengthening the quadriceps femoris muscle in elderly women with knee osteoarthritis. PMID:25931718

  7. Development of a mathematical model for predicting electrically elicited quadriceps femoris muscle forces during isovelocity knee joint motion

    PubMed Central

    Perumal, Ramu; Wexler, Anthony S; Binder-Macleod, Stuart A

    2008-01-01

    Background Direct electrical activation of skeletal muscles of patients with upper motor neuron lesions can restore functional movements, such as standing or walking. Because responses to electrical stimulation are highly nonlinear and time varying, accurate control of muscles to produce functional movements is very difficult. Accurate and predictive mathematical models can facilitate the design of stimulation patterns and control strategies that will produce the desired force and motion. In the present study, we build upon our previous isometric model to capture the effects of constant angular velocity on the forces produced during electrically elicited concentric contractions of healthy human quadriceps femoris muscle. Modelling the isovelocity condition is important because it will enable us to understand how our model behaves under the relatively simple condition of constant velocity and will enable us to better understand the interactions of muscle length, limb velocity, and stimulation pattern on the force produced by the muscle. Methods An additional term was introduced into our previous isometric model to predict the force responses during constant velocity limb motion. Ten healthy subjects were recruited for the study. Using a KinCom dynamometer, isometric and isovelocity force data were collected from the human quadriceps femoris muscle in response to a wide range of stimulation frequencies and patterns. % error, linear regression trend lines, and paired t-tests were used to test how well the model predicted the experimental forces. In addition, sensitivity analysis was performed using Fourier Amplitude Sensitivity Test to obtain a measure of the sensitivity of our model's output to changes in model parameters. Results Percentage RMS errors between modelled and experimental forces determined for each subject at each stimulation pattern and velocity showed that the errors were in general less than 20%. The coefficients of determination between the measured

  8. Motor unit synchronization in FDI and biceps brachii muscles of strength-trained males.

    PubMed

    Fling, Brett W; Christie, Anita; Kamen, Gary

    2009-10-01

    Motor unit (MU) synchronization is the simultaneous or near-simultaneous firing of two MUs which occurs more often than would be expected by chance. The present study sought to investigate the effects of exercise training, muscle group, and force level, by comparing the magnitude of synchronization in the biceps brachii (BB) and first dorsal interosseous (FDI) muscles of untrained and strength-trained college-aged males at two force levels, 30% of maximal voluntary contraction (MVC) and 80% MVC. MU action potentials were recorded directly via an intramuscular needle electrode. The magnitude of synchronization was assessed using previously-reported synchronization indices: k', E, and CIS. Synchronization was significantly higher in the FDI than in the BB. Greater synchronization was observed in the strength-trained group with CIS, but not with E or k'. Also, synchronization was significantly greater at 80% MVC than at 30% MVC with E, but only moderately greater with CIS and there was no force difference with k'. Synchronization prevalence was found to be greater in the BB (80.1%) than in the FDI (71.5%). Thus, although the evidence is a bit equivocal, it appears that MU synchronization is greater at higher forces, and greater in strength-trained individuals than in untrained subjects.

  9. Kinesiology Taping does not Modify Electromyographic Activity or Muscle Flexibility of Quadriceps Femoris Muscle: A Randomized, Placebo-Controlled Pilot Study in Healthy Volleyball Players

    PubMed Central

    Halski, Tomasz; Dymarek, Robert; Ptaszkowski, Kuba; Słupska, Lucyna; Rajfur, Katarzyna; Rajfur, Joanna; Pasternok, Małgorzata; Smykla, Agnieszka; Taradaj, Jakub

    2015-01-01

    Background Kinesiology taping (KT) is a popular method of supporting professional athletes during sports activities, traumatic injury prevention, and physiotherapeutic procedures after a wide range of musculoskeletal injuries. The effectiveness of KT in muscle strength and motor units recruitment is still uncertain. The objective of this study was to assess the effect of KT on surface electromyographic (sEMG) activity and muscle flexibility of the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) muscles in healthy volleyball players. Material/Methods Twenty-two healthy volleyball players (8 men and 14 women) were included in the study and randomly assigned to 2 comparative groups: “kinesiology taping” (KT; n=12; age: 22.30±1.88 years; BMI: 22.19±4.00 kg/m2) in which KT application over the RF muscle was used, and “placebo taping” (PT; n=10; age: 21.50±2.07 years; BMI: 22.74±2.67 kg/m2) in which adhesive nonelastic tape over the same muscle was used. All subjects were analyzed for resting sEMG activity of the VL and VM muscles, resting and functional sEMG activity of RF muscle, and muscle flexibility of RF muscle. Results No significant differences in muscle flexibility of the RF muscle and sEMG activity of the RF, VL, and VM muscles were registered before and after interventions in both groups, and between the KT and PT groups (p>0.05). Conclusions The results show that application of the KT to the RF muscle is not useful to improve sEMG activity. PMID:26232122

  10. Leg muscle activation and distance setting of the leg cycle ergometer for use by the elderly.

    PubMed

    Kim, Seon-Chill; Lee, Sang-Yeol; Lee, Young-Ik

    2014-10-01

    [Purpose] This study verified the leg muscle activities of elderly subjects performing leg cycle ergometer exercise. [Subjects] Forty-one elderly persons were the subjects of this study. [Methods] For the three distances corresponding to knee flexion angles of 15, 45, and 70, the muscle activities of the rectus femoris, biceps femoris, tibialis anterior and lateral gastrocnemius were measured while the subjects exercised on a cycle ergometer. [Results] The rectus femoris and biceps femoris showed statistically significant increases as the distance between the cycle ergometer and the body increased, and the lateral gastrocnemius muscle activation showed a statistically significant increase as the distance from the body to the cycle ergometer decreased. [Conclusion] When the elderly have limb muscle weakness, leg cycle ergometer distances should be adjusted.

  11. Local architecture of the vastus intermedius is a better predictor of knee extension force than that of the other quadriceps femoris muscle heads.

    PubMed

    Ando, Ryosuke; Saito, Akira; Umemura, Yoshihisa; Akima, Hiroshi

    2015-09-01

    The purpose of this study was to determine whether the muscle architecture of each head of the quadriceps femoris (QF) at multiple regions can be used to predict knee extension force. Muscle thickness and pennation angle were measured using sonographic images from multiple regions on each muscle of the QF with the knee flexed to 90°. The fascicle lengths of the rectus femoris (RF), vastus lateralis (VL) and vastus intermedius (VI) muscles were estimated based on sonographic images taken along the length of the thigh. The muscle architecture of the vastus intermedius was determined in two separate locations using sonographic images of the anterior (ant-VI) and lateral portions (lat-VI). The maximal voluntary contraction (MVC) was measured during isometric knee extension at a knee joint angle of 90°. The relationship between MVC force and muscle architecture was examined using a stepwise linear regression analysis with MVC force as the dependent variable. The muscle thickness of the ant-VI was selected as an independent variable in the first step of the linear regression analysis (R(2) = 0.66, P<0.01). In the second step, pennation angle of the lat-VI was added to the model (R(2) = 0.91, P<0.01). These results suggest that among the four muscles that make up the QF, the muscle architecture of the VI is the best predictor of knee extension force.

  12. Computed tomography of hamstring muscle strains.

    PubMed

    Garrett, W E; Rich, F R; Nikolaou, P K; Vogler, J B

    1989-10-01

    Acute hamstring muscle strains occurring in ten college athletes were evaluated using computed tomography to identify the location and characteristics of these common injuries. Acute muscle strains appeared as areas of hypodensity within the muscle 1-2 d following injury. This suggests that inflammation and edema are the major component of injury, not bleeding as commonly assumed. Injuries were seen most commonly in the proximal and lateral portions of the hamstring muscle group, particularly in the biceps femoris.

  13. Ultrasonic characterisation of B. femoris from Iberian pigs of different genetics and feeding systems.

    PubMed

    Niñoles, L; Mulet, A; Ventanas, S; Benedito, J

    2011-10-01

    Ultrasonic velocity was used to characterise the differences in composition and texture of Biceps Femoris muscles from four batches of pigs of different genetics (Iberian and Iberian × Duroc) and feeding systems ("montanera" and concentrate). Significant differences (p<0.05) were found for the ultrasonic velocity in samples with different genetics and feeding systems. These differences were dependent on the temperature of the measurements and were related to the intramuscular fat content (IMF) of the samples and, therefore, to the meat quality. The ultrasonic velocities at 0 and 20 °C were related to the IMF (R=0.77 and 0.65, respectively). A discriminant analysis, including ultrasonic velocity at temperatures from 0 to 20 °C, allowed 87.0% of the samples to be correctly classified in the batches. Therefore, ultrasonics could be useful in the characterisation and differentiation of B. femoris muscles of Iberian pigs with different genetics and from different feeding systems.

  14. Electromyographic analysis of thigh muscles during track cycling on a velodrome.

    PubMed

    Watanabe, Kohei; Sato, Takayuki; Mukaimoto, Takahiro; Takashima, Wataru; Yamagishi, Michio; Nishiyama, Tetsunari

    2016-08-01

    We aimed to investigate neuromuscular activation of thigh muscles during track cycling at various speeds. Eight male competitive cyclists volunteered to participate in this study. Surface electromyography of the vastus lateralis, biceps femoris and adductor magnus muscles of the bilateral legs was recorded during track cycling on velodromes with a 250-m track. The participants were instructed to maintain three different lap times: 20, 18 and 16 s. The average rectified value (ARV) was calculated from the sampled surface electromyography. Significantly higher ARVs were observed in the right compared to left leg for the biceps femoris muscle during both straight and curved sections at 18- and 16-s lap times (P < 0.05). In the biceps femoris muscle, significant changes in ARVs during the recovery phase with an increase in speed were seen in the right leg only (P < 0.05). There were no significant differences in ARVs between the straight and curved sections for all three muscles (P > 0.05). From our findings, it was suggested that during track cycling on a velodrome the laterality of the biceps femoris muscle activity is a key strategy to regulate the speed, and fixed neuromuscular strategies are adopted between straight and curved sections for thigh muscles.

  15. Localized Electrical Impedance Myography of the Biceps Brachii Muscle during Different Levels of Isometric Contraction and Fatigue

    PubMed Central

    Li, Le; Shin, Henry; Li, Xiaoyan; Li, Sheng; Zhou, Ping

    2016-01-01

    This study assessed changes in electrical impedance myography (EIM) at different levels of isometric muscle contraction as well as during exhaustive exercise at 60% maximum voluntary contraction (MVC) until task failure. The EIM was performed on the biceps brachii muscle of 19 healthy subjects. The results showed that there was a significant difference between the muscle resistance (R) measured during the isometric contraction and when the muscle was completely relaxed. Post hoc analysis shows that the resistance increased at higher contractions (both 60% MVC and MVC), however, there were no significant changes in muscle reactance (X) during the isometric contractions. The resistance also changed during different stages of the fatigue task and there were significant decreases from the beginning of the contraction to task failure as well as between task failure and post fatigue rest. Although our results demonstrated an increase in resistance during isometric contraction, the changes were within 10% of the baseline value. These changes might be related to the modest alterations in muscle architecture during a contraction. The decrease in resistance seen with muscle fatigue may be explained by an accumulation of metabolites in the muscle tissue. PMID:27110795

  16. Biarticular leg muscles and links to running economy.

    PubMed

    Heise, G; Shinohara, M; Binks, L

    2008-08-01

    Relationships between an index of running economy (VO2 per distance) and the temporal electromyographic characteristics of leg muscles were quantified in female runners. Sixteen women performed a 30-min treadmill run at a speed designed to elicit a hard rating of perceived of exertion. Near the end of the run, oxygen uptake, video, and electromyographic data were collected simultaneously. Measures of muscle on-time durations, and on-time coactivation durations were calculated from the following muscles: gastrocnemius, vastus lateralis, rectus femoris, and biceps femoris. Nonparametric correlations between VO2 per distance and temporal electromyographic data were evaluated. Greater on-time duration of rectus femoris during stance, and greater on-time coactivation duration of rectus femoris-gastrocnemius during stance were significantly associated with more economical runners (i.e., lower VO2 per distance). The coactivation of biarticular leg muscles during stance is clearly linked to running economy and this control strategy may elicit greater elastic energy return.

  17. Functional evaluation of patients with injury of the distal insertion of the biceps brachii muscle treated surgically☆☆☆

    PubMed Central

    Miyazaki, Alberto Naoki; Fregoneze, Marcelo; Santos, Pedro Doneux; da Silva, Luciana Andrade; do Val Sella, Guilherme; Duarte, Denis Cabral; Checchia, Sergio Luiz

    2014-01-01

    Objective to functionally evaluate patients with injury of the distal insertion of the biceps brachii muscle that was treated surgically. Methods between April 2002 and June 2011, 15 elbows of 14 patients underwent surgical treatment performed by the Shoulder and Elbow Surgery Group, Department of Orthopedics and Traumatology, School of Medical Sciences, Santa Casa de São Paulo. The minimum follow-up was six months, with a mean of 28 months. The patients’ ages ranged from 28 to 62 years, with a mean age of 40 years. All the patients were male and the dominant arm was affected in 64.2%. The clinical evaluation on the results was conducted using the criteria of the American Medical Association (AMA), as modified by Bruce, with evaluation of the joint range of motion (flexion–extension and pronosupination), the presence of pain and the patient's degree of satisfaction. Results from the AMA criteria, as modified by Bruce, we obtained 100% satisfactory results, of which 85.7% were considered to be excellent and 14.3% good. We observed that when distal injuries of the biceps brachii muscle affected young and active patients, surgical treatment was a good option. PMID:26229788

  18. Immediate effects of acupuncture on biceps brachii muscle function in healthy and post-stroke subjects

    PubMed Central

    2012-01-01

    Background The effects of acupuncture on muscle function in healthy subjects are contradictory and cannot be extrapolated to post-stroke patients. This study evaluated the immediate effects of manual acupuncture on myoelectric activity and isometric force in healthy and post-stroke patients. Methods A randomized clinical trial, with parallel groups, single-blinded study design, was conducted with 32 healthy subjects and 15 post-stroke patients with chronic hemiparesis. Surface electromyography from biceps brachii during maximal isometric voluntary tests was performed before and after 20-min intermittent, and manual stimulation of acupoints Quchi (LI11) or Tianquan (PC2). Pattern differentiation was performed by an automated method based on logistic regression equations. Results Healthy subjects showed a decrease in the root mean-squared (RMS) values after the stimulation of LI11 (pre: 1.392 ± 0.826 V; post: 0.612 ± 0.0.320 V; P = 0.002) and PC2 (pre: 1.494 ± 0.826 V; post: 0.623 ± 0.320 V; P = 0.001). Elbow flexion maximal isometric voluntary contraction (MIVC) was not significantly different after acupuncture stimulation of LI11 (pre: 22.2 ± 10.7 kg; post: 21.7 ± 9.5 kg; P = 0.288) or PC2 (pre: 18.8 ± 4.6 kg; post: 18.7 ± 6.0 kg; P = 0.468). Post-stroke patients did not exhibit any significant decrease in the RMS values after the stimulation of LI11 (pre: 0.627 ± 0.335 V; post: 0.530 ± 0.272 V; P = 0.187) and PC2 (pre: 0.601 ± 0.258 V; post: 0.591 ± 0.326 V; P = 0.398). Also, no significant decrease in the MIVC value was observed after the stimulation of LI11 (pre: 9.6 ± 3.9 kg; post: 9.6 ± 4.7 kg; P = 0.499) or PC2 (pre: 10.7 ± 5.6 kg; post: 10.2 ± 5.3 kg; P = 0.251). Different frequency of patterns was observed among healthy subjects and post-stroke patients groups (χ2 = 9.759; P = 0.021). Conclusion Manual acupuncture provides sufficient neuromuscular stimuli to promote immediate changes in motor unit gross recruitment without repercussion in

  19. Driving Sodium-Potassium Pumps With An Oscillating Electric Field: Effects On Muscle Recovery In The Human Biceps Brachii

    NASA Astrophysics Data System (ADS)

    Bovyn, Matt; Chen, Wei; Lanes, Olivia; Mast, Jason

    2013-03-01

    Dr. Chen has developed a technique called synchronization modulation, which uses an oscillating electric field to increase the rate at which the sodium-potassium pumps in the cell membrane work. Because the sodium-potassium pump is integral in the recovery of skeletal muscle fibers after an action potential, we investigated the effects of applying synchronization modulation to muscles which had already undergone fatigue due to repeated action potentials during exercise. Fatigue was induced in human subjects' biceps brachii through isometric contraction. Surface electromyography measurements of fatigue index were used to quantify how the muscle recovered over the minutes following fatigue, both when synchronization modulation was applied and when it was absent. The preliminary results were inconclusive, but it is hoped that in later work it will be shown that applying synchronization modulation is effective in increasing the rate at which the muscle recovers to its initial state. This would demonstrate not only that synchronization modulation can be successfully applied to human muscle, but also that it has many potential applications in sports medicine and novel disease treatments. Work done as part of an REU program at the University of South Florida

  20. Muscle activity in the lower limbs during push-down movement with a new active-exercise apparatus for the leg

    PubMed Central

    Tanaka, Kenta; Kamada, Hiroshi; Shimizu, Yukiyo; Aikawa, Shizu; Irie, Shun; Ochiai, Naoyuki; Sakane, Masataka; Yamazaki, Masashi

    2016-01-01

    [Purpose] Lower-limb deep vein thrombosis is a complication of orthopedic surgery. A leg-exercise apparatus named “LEX” was developed as a novel active-exercise apparatus for deep vein thrombosis prevention. Muscle activity was evaluated to assess the effectiveness of exercise with LEX in the prevention. [Subjects] Eight healthy volunteers participated in this study. [Methods] Muscle activities were determined through electromyography during exercise with LEX [LEX (+)] and during active ankle movements [LEX (−)]. The end points were peak % maximum voluntary contraction and % integrated electromyogram of rectus femoris, vastus lateralis, biceps femoris, tibialis anterior, gastrocnemius, and soleus. [Results] LEX (+) resulted in higher average values in all muscles except the tibialis anterior. Significant differences were noted in the peak of the biceps femoris and gastrocnemius and in the integrated electromyogram of the rectus femoris, vastus lateralis, gastrocnemius, and soleus. The LEX (+)/LEX (−) ratio of the peak was 2.2 for the biceps femoris and 2.0 for the gastrocnemius . The integrated electromyogram was 1.8 for the gastrocnemius, 1.5 for the rectus femoris, 1.4 for the vastus lateralis, and 1.2 for the soleus. [Conclusion] Higher muscle activity was observed with LEX (+). LEX might be a good tool for increasing lower-limb blood flow and deep vein thrombosis prevention. PMID:27134410

  1. Dry Needling at Myofascial Trigger Spots of Rabbit Skeletal Muscles Modulates the Biochemicals Associated with Pain, Inflammation, and Hypoxia

    PubMed Central

    Hsieh, Yueh-Ling; Yang, Shun-An; Yang, Chen-Chia; Chou, Li-Wei

    2012-01-01

    Background and Purpose. Dry needling is an effective therapy for the treatment of pain associated with myofascial trigger point (MTrP). However, the biochemical effects of dry needling that are associated with pain, inflammation, and hypoxia are unclear. This study investigated the activities of β-endorphin, substance P, TNF-α, COX-2, HIF-1α, iNOS, and VEGF after different dosages of dry needling at the myofascial trigger spots (MTrSs) of a skeletal muscle in rabbit. Materials and Methods. Dry needling was performed either with one dosage (1D) or five dosages (5D) into the biceps femoris with MTrSs in New Zealand rabbits. Biceps femoris, serum, and dorsal root ganglion (DRG) were sampled immediately and 5 d after dry needling for β-endorphin, substance P, TNF-α, COX-2, HIF-1α, iNOS, and VEGF immunoassays. Results. The 1D treatment enhanced the β-endorphin levels in the biceps femoris and serum and reduced substance P in the biceps femoris and DRG. The 5D treatment reversed these effects and was accompanied by increase of TNF-α, COX-2, HIF-1α, iNOS, and VEGF production in the biceps femoris. Moreover, the higher levels of these biochemicals were still maintained 5 d after treatment. Conclusion. Dry needling at the MTrSs modulates various biochemicals associated with pain, inflammation, and hypoxia in a dose-dependent manner. PMID:23346198

  2. Dry needling at myofascial trigger spots of rabbit skeletal muscles modulates the biochemicals associated with pain, inflammation, and hypoxia.

    PubMed

    Hsieh, Yueh-Ling; Yang, Shun-An; Yang, Chen-Chia; Chou, Li-Wei

    2012-01-01

    Background and Purpose. Dry needling is an effective therapy for the treatment of pain associated with myofascial trigger point (MTrP). However, the biochemical effects of dry needling that are associated with pain, inflammation, and hypoxia are unclear. This study investigated the activities of β-endorphin, substance P, TNF-α, COX-2, HIF-1α, iNOS, and VEGF after different dosages of dry needling at the myofascial trigger spots (MTrSs) of a skeletal muscle in rabbit. Materials and Methods. Dry needling was performed either with one dosage (1D) or five dosages (5D) into the biceps femoris with MTrSs in New Zealand rabbits. Biceps femoris, serum, and dorsal root ganglion (DRG) were sampled immediately and 5 d after dry needling for β-endorphin, substance P, TNF-α, COX-2, HIF-1α, iNOS, and VEGF immunoassays. Results. The 1D treatment enhanced the β-endorphin levels in the biceps femoris and serum and reduced substance P in the biceps femoris and DRG. The 5D treatment reversed these effects and was accompanied by increase of TNF-α, COX-2, HIF-1α, iNOS, and VEGF production in the biceps femoris. Moreover, the higher levels of these biochemicals were still maintained 5 d after treatment. Conclusion. Dry needling at the MTrSs modulates various biochemicals associated with pain, inflammation, and hypoxia in a dose-dependent manner.

  3. Muscle oxygen saturation heterogeneity among leg muscles during ramp exercise.

    PubMed

    Takagi, Shun; Kime, Ryotaro; Niwayama, Masatsugu; Murase, Norio; Katsumura, Toshihito

    2013-01-01

    We examined whether O(2) saturation in several leg muscles changes as exercise intensity increases. Twelve healthy young males performed 20 W/min ramp bicycle exercise until exhaustion. Pulmonary O(2) uptake (VO(2)) was monitored continuously during the experiments to determine peak oxygen uptake. Muscle O(2) saturation (SmO(2)) was also monitored continuously at the belly of the vastus lateralis (VL), rectus femoris, vastus medialis, biceps femoris, gastrocnemius lateralis, gastrocnemius medialis, and tibialis anterior by near-infrared spatial resolved spectroscopy. Although the VL muscle mainly contributes during cycling exercise, deoxygenation was enhanced not only in the VL muscle but also in the other thigh muscles and lower leg muscles with increased exercise intensity. Furthermore, SmO(2) response during ramp cycling exercise differed considerably between leg muscles.

  4. Hereditary rimmed vacuole myopathy showing interstitial amyloid deposition in muscle tissue.

    PubMed

    Kojima, Yukiko; Sakai, Kenji; Ishida, Chiho; Asaka, Tomoya; Hamaguchi, Tsuyoshi; Nozaki, Ichiro; Fukushima, Kazuhiro; Tsuchiya, Ayako; Kametani, Fuyuki; Yazaki, Masahide; Okino, Soichi; Yamada, Masahito

    2009-09-01

    We describe a consanguineous family that had progressive myopathy with rimmed vacuole (RV) formation and amyloid deposition. Patient 1 is a 71-year-old woman with muscle atrophy in the lumbar girdle and lower extremities. Patient 2 is a 40-year-old man (the son of Patient 1) with fatty changes in the biceps femoris muscles. Muscle biopsies revealed myopathic and neurogenic degeneration with RV, necrotic fibers, and interstitial amyloid deposition. Amyloid deposition was detected only in the muscle tissue.

  5. The dependence between clinical condition and value of the maximum force in the quadriceps femoris muscle during MVC test in patients with knee osteoarthritis.

    PubMed

    Nowak, Karina; Sobota, Grzegorz; Bacik, Bogdan; Hajduk, Grzegorz; Kusz, Damian

    2012-01-01

    The aim of this study was to check whether there was a correlation between the value of the maximum developed torque of the quadriceps femoris muscle and subjective evaluation of a patient's pain which is measured by the VAS. Also evaluated were changes in the muscle torque value and KSS scale over time. For examining patient's condition use was made of a KSS scale (knee score: pain, range of motion, stability of joint and limb axis) before the surgery and in weeks 6 and 12, as well as 6 months after surgery. It was found to be constantly improving in comparison with the condition before the surgery. This is confirmed by a significant statistical value difference of KSS scale. The surgery substantially increases the quality of live and function recurrence.

  6. Impact of decline-board squat exercises and knee joint angles on the muscle activity of the lower limbs

    PubMed Central

    Lee, Daehee; Lee, Sangyong; Park, Jungseo

    2015-01-01

    [Purpose] This study aims to investigate how squat exercises on a decline board and how the knee joint angles affect the muscle activity of the lower limbs. [Subjects] The subjects were 26 normal adults. [Methods] A Tumble Forms wedge device was used as the decline board, and the knee joint angles were measured with a goniometer. To examine the muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior of the lower limbs, a comparison analysis with electromyography was conducted. [Results] The muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior increased with increased knee joint angles, both for squat exercises on the decline board and on a flat floor. When the knee joint angle was 45°, 60°, and 90°, the muscle activity of the rectus femoris was significantly higher and that of the tibialis anterior was significantly lower during squat exercises on the decline board than on the flat floor. When the knee joint angle was 90°, the muscle activity of the gastrocnemius lateralis was significantly lower. [Conclusion] Squat exercises on a decline board are an effective intervention to increase the muscle activity of the rectus femoris with increased knee joint angles. PMID:26357447

  7. Selection of muscles as indicators of tenderness after seven days of ageing.

    PubMed

    Simões, J A; Mendes, M I; Lemos, J P C

    2005-04-01

    The selection of a muscle that could be used as an index muscle for beef tenderness was performed using nine commercially important muscles. A total of 50 bulls, Charolais×Alentejano (n=9), Simmental×Alentejano (n=9) and Alentejano (n=32), were slaughtered at two different commercial live weights: crossbred animals (sample A) between 500 and 600 kg (carcass weight between 310 and 370 kg) and purebred Alentejano (sample B) between 350 and 450 kg (carcass weight between 185 and 295 kg). Slaughter ages varied between 16 and 24 months in both groups. The shear force of nine muscles (Mm. biceps femoris, gastrocnemius, longissimus thoracis, longissimus lumborum, quadriceps femoris, semimembranosus, semitendinosus, supraspinatus and triceps brachii caput longum) was assessed seven days post-mortem. In both samples, the comparison between different muscle means and the combined mean of all muscles and the respective correlations showed that the Mm. biceps femoris and semimembranosus could be used as index muscles. However, the biceps femoris is preferred, because it showed greater stability in terms of the coefficient of variation.

  8. Effects of wearing gumboots and leather lace-up boots on lower limb muscle activity when walking on simulated underground coal mine surfaces.

    PubMed

    Dobson, Jessica A; Riddiford-Harland, Diane L; Steele, Julie R

    2015-07-01

    This study aimed to investigate the effects of wearing two standard underground coal mining work boots (a gumboot and a leather lace-up boot) on lower limb muscle activity when participants walked across simulated underground coal mining surfaces. Quadriceps (rectus femoris, vastus medialis, vastus lateralis) and hamstring (biceps femoris, semitendinosus) muscle activity were recorded as twenty male participants walked at a self-selected pace around a circuit while wearing each boot type. The circuit consisted of level, inclined and declined surfaces composed of rocky gravel and hard dirt. Walking in a leather lace-up boot, compared to a gumboot, resulted in increased vastus lateralis and increased biceps femoris muscle activity when walking on sloped surfaces. Increased muscle activity appears to be acting as a slip and/or trip prevention strategy in response to challenging surfaces and changing boot features.

  9. Effects of wearing gumboots and leather lace-up boots on lower limb muscle activity when walking on simulated underground coal mine surfaces.

    PubMed

    Dobson, Jessica A; Riddiford-Harland, Diane L; Steele, Julie R

    2015-07-01

    This study aimed to investigate the effects of wearing two standard underground coal mining work boots (a gumboot and a leather lace-up boot) on lower limb muscle activity when participants walked across simulated underground coal mining surfaces. Quadriceps (rectus femoris, vastus medialis, vastus lateralis) and hamstring (biceps femoris, semitendinosus) muscle activity were recorded as twenty male participants walked at a self-selected pace around a circuit while wearing each boot type. The circuit consisted of level, inclined and declined surfaces composed of rocky gravel and hard dirt. Walking in a leather lace-up boot, compared to a gumboot, resulted in increased vastus lateralis and increased biceps femoris muscle activity when walking on sloped surfaces. Increased muscle activity appears to be acting as a slip and/or trip prevention strategy in response to challenging surfaces and changing boot features. PMID:25766420

  10. Distal biceps brachii.

    PubMed

    Brigido, Monica Kalume; De Maeseneer, Michel; Morag, Yoav

    2013-02-01

    There has been a renewed interest in the recent literature with regard to the normal anatomy of the distal biceps tendon. Cadaveric studies have demonstrated that a large percentage of individuals have two independent muscle bellies, the short and the long head, with two distinct separate tendons attaching at the radial tuberosity. To avoid diagnostic errors that may have an impact on patient management in case of tendon injury, it is important to keep this anatomical variant in mind. Ultrasonography has been shown to be a useful imaging modality in the evaluation of disorders of the distal biceps brachii muscle and tendon. In this article, we review the relevant anatomy of the distal biceps brachii, the ultrasound technique with alternative approaches for optimum visualization of the distal tendon, and the most common pathologies in this region.

  11. The growth patterns of three hindlimb muscles in the chicken.

    PubMed

    Helmi, C; Cracraft, J

    1977-07-01

    This study was designed to investigate the growth patterns of three hindlimb muscles of the chicken relative to the functional-biomechanical demands of increasing body size. The biceps femoris, a bipennate non-postural muscle, grew relatively faster in terms of wet and dry weight than did the parallel-fibred adductor superficialis or the unipennate adductor profundus, both postural muscles. All three muscles exhibited positive allometry (relative to body weight) in muscle length but only biceps femoris and adductor profundus showed positive allometry in cross sectional area adductor superficialis having isometric growth in this parameter. In biceps femoris and adductor superficialis the lengths of the longest and shortest fasciculi grew at equal rates, whereas in adductor profundus the shortest fasciculi grew faster than the longest. We conclude that muscle weight alone is an insufficient indicator of changing function in growing muscle. Hence, growth studies should include other functionally relevant parameters such as cross sectional area, which is proportional to the force-producing capabilities of the muscle, or fibre (fasciculus) length, which is indicative of the absolute amount of stretching or shortening that is possible and of the contraction velocity.

  12. The growth patterns of three hindlimb muscles in the chicken.

    PubMed Central

    Helmi, C; Cracraft, J

    1977-01-01

    This study was designed to investigate the growth patterns of three hindlimb muscles of the chicken relative to the functional-biomechanical demands of increasing body size. The biceps femoris, a bipennate non-postural muscle, grew relatively faster in terms of wet and dry weight than did the parallel-fibred adductor superficialis or the unipennate adductor profundus, both postural muscles. All three muscles exhibited positive allometry (relative to body weight) in muscle length but only biceps femoris and adductor profundus showed positive allometry in cross sectional area adductor superficialis having isometric growth in this parameter. In biceps femoris and adductor superficialis the lengths of the longest and shortest fasciculi grew at equal rates, whereas in adductor profundus the shortest fasciculi grew faster than the longest. We conclude that muscle weight alone is an insufficient indicator of changing function in growing muscle. Hence, growth studies should include other functionally relevant parameters such as cross sectional area, which is proportional to the force-producing capabilities of the muscle, or fibre (fasciculus) length, which is indicative of the absolute amount of stretching or shortening that is possible and of the contraction velocity. PMID:885779

  13. The effect of temperature on proliferation and differentiation of chicken skeletal muscle satellite cells isolated from different muscle types.

    PubMed

    Harding, Rachel L; Halevy, Orna; Yahav, Shlomo; Velleman, Sandra G

    2016-04-01

    Skeletal muscle satellite cells are a muscle stem cell population that mediate posthatch muscle growth and repair. Satellite cells respond differentially to environmental stimuli based upon their fiber-type of origin. The objective of this study was to determine how temperatures below and above the in vitro control of 38°C affected the proliferation and differentiation of satellite cells isolated from the chicken anaerobic pectoralis major (p. major) or mixed fiber biceps femoris (b.femoris) muscles. The satellite cells isolated from the p. major muscle were more sensitive to both cold and hot temperatures compared to the b.femoris satellite cells during both proliferation and differentiation. The expressions of myogenic regulatory transcription factors were also different between satellite cells from different fiber types. MyoD expression, which partially regulates proliferation, was generally expressed at higher levels in p. major satellite cells compared to the b.femoris satellite cells from 33 to 43°C during proliferation and differentiation. Similarly, myogenin expression, which is required for differentiation, was also expressed at higher levels in p. major satellite cells in response to both cold and hot temperatures during proliferation and differentiation than b. femoris satellite cells. These data demonstrate that satellite cells from the anaerobic p. major muscle are more sensitive than satellite cells from the aerobic b. femoris muscle to both hot and cold thermal stress during myogenic proliferation and differentiation.

  14. Biceps sternalis: a Y-shaped muscle on the anterior chest wall

    PubMed Central

    2013-01-01

    The sternalis muscle is an accessory muscle located in the anterior thoracic region, which is relatively unfamiliar to clinicians and surgeons. To date, no data from the Iranian population have been published. Here, a rare case of a sternalis muscle is presented. In addition, this anomalous muscle was observed along with other visceral and vascular anomalies. This case is unique and provides significant information to radiologists, angiologists and surgeons seeking to apply safer interventions. It is also imperative for better interpretation of mammographic images and in reconstructive surgery. PMID:23497563

  15. MUSCLE TRANSFER FROM TRICEPS TO BICEPS IN PATIENTS WITH CHRONIC INJURY OF THE UPPER TRUNK OF THE BRACHIAL PLEXUS

    PubMed Central

    Souza, Fabiano Inúcio de; Saito, Mateus; Kimura, Luiz Koiti; Júnior, Rames Mattar; Zumiotti, Arnaldo Valdir

    2015-01-01

    Objective: To evaluate the results from transposition of the triceps for elbow flexion in patients with chronic and complete injury to the upper trunk of the brachial plexus. Methods: This was a retrospective study, including only patients who had biceps grade 0 and triceps grade 5, who underwent anterior transfer of the triceps muscle, performed between 1998 and 2005. The affected side, sex, type of accident, strength of elbow flexion, complications and patient satisfaction were investigated in 11 cases. Results: 10 patients were male; the age range was from 24 to 49 years, with a mean of 33.7 years. The minimum time between injury and surgery was 21 months (range 21-74 months). The left side was affected in eight cases, and the right only in three. Good results were obtained in 10 patients, who acquired elbow flexion strength of grade 3 (two cases) and grade 4 (eight cases), while one evolved unfavorably with grade 2 strength. Two cases had complications (initial compartment syndrome and insufficient tensioning). All the patients said that they were satisfied with the procedure. Conclusion: Anterior transposition of the triceps muscle provided patient satisfaction in all cases except one, attaining strength grade 4 in eight cases, grade 3 in two cases and grade 2 in one case. PMID:27022572

  16. Lower extremity muscles activity in standing and sitting position with use of sEMG in patients suffering from Charcot-Marie-Tooth syndrome.

    PubMed

    Kuciel, Natalia Maria; Konieczny, Grzegorz Krzysztof; Oleksy, Łukasz; Wrzosek, Zdzisława

    2016-01-01

    There is very limited, evidenced data about movement possibilities in patients with high level of lower limb muscles atrophy and fatigue in patients suffering from Charcot-Marie-Tooth syndrome. Patient (age 46) suffering from Charcot-Marie-Tooth disease for 30 years with multiple movement restrictions and muscles atrophy above knees took part into the study. Tests were performed for 8 muscles of the lower limb and pelvis. Muscles electrical activity was tested in sitting and standing position (for knees extended and hyperextended). In the right leg rectus femoris, vastus lateralis obliquus, gluteus medius and semitendinosus muscles activated at first and were working the longest time. The highest activity was observed in standing position with knees extended. In the left leg rectus femoris and biceps femoris muscles activated at first and biceps femoris was working the longest time. Activity level in left lower limb is much lower than in the right one. Muscles weakness is asymmetric. Left leg is much weaker and engages antagonists and synergists muscles to compensate weaker rectus femoris, vastus medialis obliquus and vastus lateralis obliquus.

  17. [Amino acid composition of the rat quadriceps femoris muscle after a flight on the Kosmos-936 biosatellite].

    PubMed

    Vlasova, T F; Miroshnikova, E B; Poliakov, V V; Murugova, T P

    1982-01-01

    The amino acid composition of the quadriceps muscle of rats flown onboard the biosatellite Cosmos-936 and exposed to the ground-based synchronous control experiment was studied. The weightless rats showed changes in the amino acid concentration in the quadriceps muscle. The centrifuged flight and synchronous rats displayed an accumulation of free amino acids in the above muscle.

  18. Stretchability of the rectus femoris muscle: investigation of validity and intratester reliability of two methods including X-ray analysis of pelvic tilt.

    PubMed

    Hamberg, J; Björklund, M; Nordgren, B; Sahlstedt, B

    1993-03-01

    Validity and intratester reliability of two test methods designed to identify stretchability of the rectus femoris muscle (RFM) was investigated, combined with x-ray analysis of pelvic tilt in the sagittal plane. The first method is commonly used in clinical practice. The second is a new technique supposed to tilt the pelvis posteriorly and thus further separate the origin and insertion of the muscle. Investigation of validity and intratester reliability of the two methods was made by testing and retesting a random sample of 71 persons. The tests were performed with an equipment that automatically recorded the angle of knee flexion from a previously determined applied torque, indicating the end point of motion for that particular subject. Angle of knee flexion and subjective estimation of pain sensation due to stretch were recorded at each measurement. The pelvic tilt-analysis consisted of test-retest reliability of x-ray measurements, comparison between the methods in both starting and final position, and x-ray and electronic goniometer measurements. All applied torques were measured with a strain gauge. Two out of three criteria of validity favored the new method and the third pointed out the two methods as equal. The two methods as well as the x-ray measurements showed high reliability, and the hypothesis of a more posterior tilted pelvis in the new method was confirmed. The electronic goniometer was less sensitive than x-ray, but proposed to analyse pelvic tilt clinically. Methodology procedures for joint angle measurements are discussed.

  19. Detection of the electromechanical delay and its components during voluntary isometric contraction of the quadriceps femoris muscle

    PubMed Central

    Begovic, Haris; Zhou, Guang-Quan; Li, Tianjie; Wang, Yi; Zheng, Yong-Ping

    2014-01-01

    Electromechanical delay (EMD) was described as a time elapsed between first trigger and force output. Various results have been reported based on the measurement method with observed inconsistent results when the trigger is elicited by voluntary contraction. However, mechanomyographic (MMG) sensor placed far away on the skin from the contracting muscle was used to detect muscle fiber motion and excitation-contraction (EC) coupling which may give unreliable results. On this basis, the purpose of this study was to detect EMD during active muscle contraction whilst introducing an ultrafast ultrasound (US) method to detect muscle fiber motion from a certain depth of the muscle. Time delays between onsets of EMG-MMG, EMG-US, MMG-FORCE, US-FORCE, and EMG-FORCE were calculated as 20.5 ± 4.73, 28.63 ± 6.31, 19.21 ± 6.79, 30.52 ± 8.85, and 49.73 ± 6.99 ms, respectively. Intrarater correlation coefficient (ICC) was higher than MMG when ultrafast US was used for detecton of the Δt EMG-US and Δt US-FORCE, ICC values of 0.75 and 0.70, respectively. Synchronization of the ultrafast ultrasound with EMG and FORCE sensors can reveal reliable and clinically useful results related to the EMD and its components when muscle is voluntarily contracted. With ultrafast US, we detect onset from the certain depth of the muscle excluding the tissues above the muscle acting as a low-pass filter which can lead to inaccurate time detection about the onset of the contracting muscle fibers. With this non-invasive technique, understanding of the muscle dynamics can be facilitated. PMID:25566091

  20. Effects of forward trunk lean on hamstring muscle kinematics during sprinting.

    PubMed

    Higashihara, Ayako; Nagano, Yasuharu; Takahashi, Kazumasa; Fukubayashi, Toru

    2015-01-01

    This study aimed to investigate the effects of forward trunk lean on hamstring muscle kinematics during sprinting. Eight male sprinters performed maximal-effort sprints in two trunk positions: forward lean and upright. A three-dimensional musculoskeletal model was used to compute the musculotendon lengths and velocity of the biceps femoris long head, semitendinosus, and semimembranosus muscles during the sprinting gait cycle. The musculotendon lengths of all the three hamstring muscles at foot strike and toe-off were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. In addition, a positive peak musculotendon lengthening velocity was observed in the biceps femoris long head and semimembranosus muscles during the late stance phase, and musculotendon lengths at that instant were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. The present study provides significant evidence that a potential for hamstring muscle strain injury involving forward trunk lean sprinting would exist during the stance phase. The results also indicate that the biceps femoris long head and semimembranosus muscles are stretched during forward trunk lean sprinting while contracting eccentrically in the late stance phase; thus, the elongation load on these muscles could be increased.

  1. The impact of rectification on the electrically evoked long-latency reflex of the biceps brachii muscle.

    PubMed

    Alaid, Ssuhir; Kornhuber, Malte E

    2013-11-27

    Long latency reflexes (LLR) were elicited electrically and obtained by full wave rectified and non-rectified data recordings in 10 healthy subjects. After single or train stimuli (sensory radial nerve; interstimulus interval 3ms) amplitude and peak latency values were measured over the bent biceps brachii (BB) muscle, either without or with 1.5kg weight load. After rectification, mean LLR amplitude values made up 30% of the non-rectified data, independent from the stimulus type and weight load. In the non-rectified data, a significant gain in amplitude resulted from train stimuli compared with single stimuli, and from weight load compared to no weight load. No such significant difference was detected when rectified data were analysed. Furthermore, average amplitude values of rectified and non-rectified curves were studied using 11 sine waves and damped sine waves with equal phase intervals that were varied from 0° up to 34.4°. Phase shifts ranging from 10° to 25° resulted in excess amplitude decline of rectified data compared with non-rectified data. The long and polysynaptic course that LLR information takes leads to considerable overlap of responses to subsequent stimuli. This overlap of motor unit potentials forming the LLR obviously results in excess amplitude cancellation after rectification as shown for sine and damped sine waves. Rectification leads to an increase in the frequency content of the data that renders it prone to phase cancellation. In the present study, this cancellation was harmful as it prevented detection of important factors of influence such as stimulus strength and motor unit recruitment level.

  2. Non-invasive characterization of single motor unit electromyographic and mechanomyographic activities in the biceps brachii muscle.

    PubMed

    Cescon, Corrado; Sguazzi, Elena; Merletti, Roberto; Farina, Dario

    2006-02-01

    The aim of the study was to investigate amplitude and frequency content of single motor unit (MU) electromyographic (EMG) and mechanomyographic (MMG) responses. Multi-channel surface EMG and MMG signals were detected from the dominant biceps brachii muscle of 10 volunteers during isometric voluntary contractions at 20%, 50%, and 80% of the maximal voluntary contraction (MVC) force. Each contraction was performed three times in the experimental session which was repeated in three non-consecutive days. Single MU action potentials were identified from the surface EMG signals and their times of occurrence used to trigger the averaging of the MMG signal. At each contraction level, the MUs with action potentials of highest amplitude were identified. Single MU EMG and MMG amplitude and mean frequency were estimated with normalized standard error of the mean within subjects (due to repetition of the measure in different trials and experimental sessions) smaller than 15% and 7%, respectively, in all conditions. The amplitude of the action potentials of the detected MUs increased with increasing force (mean +/- SD, 244 +/- 116 microV at 20% MVC, and 1426 +/- 638 microV at 80% MVC; P < 0.001) while MU MMG amplitude increased from 20% to 50% MVC (40.5 +/- 20.9 and 150 +/- 88.4 mm/s(2), respectively; P<0.001) and did not change significantly between 50% and 80% MVC (129 +/ -82.7 mm/s(2) at 80% MVC). MU EMG mean frequency decreased with contraction level (20% MVC: 97.2 +/- 13.9 Hz; 80% MVC: 86.2 +/- 11.4 Hz; P < 0.001) while MU MMG mean frequency increased (20% MVC: 33.2 +/- 6.8 Hz; 80% MVC: 40.1 +/- 6.1 Hz; P < 0.001). EMG peak-to-peak amplitude and mean frequency of individual MUs were not correlated with the corresponding variables of MMG at any contraction level.

  3. Comparison of hamstring muscle behavior for anterior cruciate ligament (ACL) patient and normal subject during local marching

    NASA Astrophysics Data System (ADS)

    Amineldin@Aminudin, Nurul Izzaty Bt.; Rambely, A. S.

    2014-09-01

    This study aims to investigate the hamstring muscle activity after the surgery by carrying out an electromyography experiment on the hamstring and to compare the behavior of the ACL muscle activity between ACL patient and control subject. Electromyography (EMG) is used to study the behavior of muscles during walking activity. Two hamstring muscles involved which are semitendinosus and bicep femoris. The EMG data for both muscles were recorded while the subject did maximum voluntary contraction (MVC) and marching. The study concluded that there were similarities between bicep femoris of the ACL and control subjects. The analysis showed that the biceps femoris muscle of the ACL subject had no abnormality and the pattern is as normal as the control subject. However, ACL patient has poor semitendinosus muscle strength compared to that of control subject because the differences of the forces produced. The force of semitendinosus value for control subject was two times greater than that of the ACL subject as the right semitendinosus muscle of ACL subject was used to replace the anterior cruciate ligament (ACL) that was injured.

  4. 'Serious thigh muscle strains': beware the intramuscular tendon which plays an important role in difficult hamstring and quadriceps muscle strains.

    PubMed

    Brukner, Peter; Connell, David

    2016-02-01

    Why do some hamstring and quadriceps strains take much longer to repair than others? Which injuries are more prone to recurrence? Intramuscular tendon injuries have received little attention as an element in 'muscle strain'. In thigh muscles, such as rectus femoris and biceps femoris, the attached tendon extends for a significant distance within the muscle belly. While the pathology of most muscle injures occurs at a musculotendinous junction, at first glance the athlete appears to report pain within a muscle belly. In addition to the musculotendinous injury being a site of pathology, the intramuscular tendon itself is occasionally injured. These injuries have a variety of appearances on MRIs. There is some evidence that these injuries require a prolonged rehabilitation time and may have higher recurrence rates. Therefore, it is important to recognise the tendon component of a thigh 'muscle strain'.

  5. Muscle activation and knee biomechanics during squatting and lunging after lower extremity fatigue in healthy young women.

    PubMed

    Longpré, Heather S; Acker, Stacey M; Maly, Monica R

    2015-02-01

    Muscle activations and knee joint loads were compared during squatting and lunging before and after lower extremity neuromuscular fatigue. Electromyographic activations of the rectus femoris, vastus lateralis and biceps femoris, and the external knee adduction and flexion moments were collected on 25 healthy women (mean age 23.5 years, BMI of 23.7 kg/m(2)) during squatting and lunging. Participants were fatigued through sets of 50 isotonic knee extensions and flexions, with resistance set at 50% of the peak torque achieved during a maximum voluntary isometric contraction. Fatigue was defined as a decrease in peak isometric knee extension or flexion torque ≥25% from baseline. Co-activation indices were calculated between rectus femoris and biceps femoris; and between vastus lateralis and biceps femoris. Fatigue decreased peak isometric extension and flexion torques (p<0.05), mean vastus lateralis activation during squatting and lunging (p<0.05), and knee adduction and flexion moments during lunging (p<0.05). Quadriceps activations were greater during lunging than squatting (p<0.05). Thus, fatigue altered the recruitment strategy of the quadriceps during squatting and lunging. Lunging challenges quadriceps activation more than squatting in healthy, young women.

  6. Muscular activity of lower limb muscles associated with working on inclined surfaces.

    PubMed

    Lu, Ming-Lun; Kincl, Laurel; Lowe, Brian; Succop, Paul; Bhattacharya, Amit

    2015-01-01

    This study investigated the effects of visual cues, muscular fatigue, task performance and experience of working on inclined surfaces on activity of postural muscles in the lower limbs associated with maintaining balance on three inclined surfaces - 0°, 14° and 26°. Normalised electromyographic (NEMG) data were collected in 44 professional roofers bilaterally from the rectus femoris, biceps femoris, tibialii anterior and gastrocnemii medial muscle groups. The 50th and 95th percentile NEMG amplitudes were used as EMG variables. Results showed that inclination angle and task performance caused a significant increase in the NEMG amplitudes of all postural muscles. Visual cues were significantly associated with a decrease in the 95th percentile EMG amplitude for the right gastrocnemius medial and tibialis anterior. Fatigue was related to a significant decrease in the NEMG amplitude for the rectus femoris. Experience of working on inclined surfaces did not have a significant effect on the NEMG amplitude.

  7. Biceps tendinopathy

    PubMed Central

    Ibáñez, Maximiliano; Calvo, Ana Belén; Alvarez, Victoria; Lepore, Salvador; Ibáñez, Federico; Reybet, Juan Andrés

    2015-01-01

    Introduction: Tenodesis is the preferred technique in the treatment of the long head of the biceps tendon pathology in younger people, athletes, workers, and those wishing to avoid any cosmetic deformity. The aim of our study was to compare a group of patients who underwent all arthroscopic biceps tenodesis with a group of patients who underwent an open subpectoral procedure. A clinical assessment was performed and we also registered the occurrence of complications. Materials and Methods: We retrospectively reviewed 90 patients with lesions in the long head of the biceps tendon treated at our institution between January 2009 and January 2012. Group A underwent an arthroscopic technique while Group B was treated in an open fashion. Clinical assessment included appropriate scores (ASES, Rowe, Simple Shoulder Test, Constant Murley), and we also evaluated pain with Visual Analogue Scale (VAS), and personal satisfaction in terms of aesthetics and local pain at the scar. Results: Group A: Rowe 86 points, ASES 81 points, SST 9 points, Constant and Murley 87 points. VAS 2/10. Regarding scars of the portals patients were satisfied. Group B: Rowe 85 points, ASES 82 points, SST 8.5 points, Constant and Murley 85 points. VAS 3/10 (greater at the site of subpectoral approach). Aesthetic concerns about the scar was observed in 4 cases (4 women). Arm deformity (sign of Popeye) was not observed at the latest follow-up. Discussion: No statistical significant differences were found in clinical assessment between both procedures. Arthroscopic tenodesis is technically more challenging and requires an initial longer learning curve in order to perform a successful procedure. Open subpectoral tenodesis despite being a faster and simpler procedure reports discomfort regarding the scar site.

  8. COMPARATIVE ANALYSIS ON MUSCLE STRENGTH AMONG PATIENTS WHO UNDERWENT ARTHROSCOPIC TENOTOMY OF THE LONG HEAD OF THE BICEPS IN RELATION TO ESTHETIC DEFORMITY

    PubMed Central

    Almeida, Alexandre; Valin, Márcio Rangel; de Almeida, Nayvaldo Couto; Roveda, Gilberto; Agostini, Ana Paula

    2015-01-01

    Objective: To determine whether there was any discrepancy in elbow flexion strength among patients with and without evident clinical deformity resulting from arthroscopic tenotomy on the long head of the biceps. Method: A group of 120 patients who underwent this procedure were evaluated. After applying the exclusion criteria, 89 patients remained in the analysis. Eighteen months after the operation (median), the elbow flexion strength was measured in newtons using a digital dynamometer. Three consecutive measurements were made and the average was used. The dominant and non-dominant sides were compared. Sex, age and mean elbow flexion strength in the operated and contralateral arms of patients with and without apparent clinical deformity were evaluated. Results: The median elbow flexion strength among the patients with evident clinical deformity was 17.78 N for the dominant arm and 20.87 N for the non-dominant arm. The difference was 2.51 N. In the group without evident clinical deformity, the difference was 2.14 N. The median muscle strength in the operated arm was 17.26 N, while the median was 20.06 N in the non-operated arm, thus suggesting that there was a significant loss of muscle strength (p = 0.005). The difference in muscle strength loss between the patients with and without evident deformity was not considered statistically significant (p = 0.977). Conclusion: The patients who underwent arthroscopic tenotomy on the long head of the biceps with or without apparent clinical deformity from distal migration presented similar elbow flexion muscle strength. PMID:27047871

  9. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  10. Effects of pelvic stabilization on lumbar muscle activity during dynamic exercise.

    PubMed

    San Juan, Jun G; Yaggie, James A; Levy, Susan S; Mooney, Vert; Udermann, Brian E; Mayer, John M

    2005-11-01

    Many commonly utilized low-back exercise devices offer mechanisms to stabilize the pelvis and to isolate the lumbar spine, but the value of these mechanisms remains unclear. The purpose of this study was to examine the effect of pelvic stabilization on the activity of the lumbar and hip extensor muscles during dynamic back extension exercise. Fifteen volunteers in good general health performed dynamic extension exercise in a seated upright position on a lumbar extension machine with and without pelvic stabilization. During exercise, surface electromyographic activity of the lumbar multifidus and biceps femoris was recorded. The activity of the multifidus was 51% greater during the stabilized condition, whereas there was no difference in the activity of the biceps femoris between conditions. This study demonstrates that pelvic stabilization enhances lumbar muscle recruitment during dynamic exercise on machines. Exercise specialists can use these data when designing exercise programs to develop low back strength.

  11. ‘Serious thigh muscle strains’: beware the intramuscular tendon which plays an important role in difficult hamstring and quadriceps muscle strains

    PubMed Central

    Brukner, Peter; Connell, David

    2016-01-01

    Why do some hamstring and quadriceps strains take much longer to repair than others? Which injuries are more prone to recurrence? Intramuscular tendon injuries have received little attention as an element in ‘muscle strain’. In thigh muscles, such as rectus femoris and biceps femoris, the attached tendon extends for a significant distance within the muscle belly. While the pathology of most muscle injures occurs at a musculotendinous junction, at first glance the athlete appears to report pain within a muscle belly. In addition to the musculotendinous injury being a site of pathology, the intramuscular tendon itself is occasionally injured. These injuries have a variety of appearances on MRIs. There is some evidence that these injuries require a prolonged rehabilitation time and may have higher recurrence rates. Therefore, it is important to recognise the tendon component of a thigh ‘muscle strain’. PMID:26519522

  12. The influence of different jaw positions on the endurance and electromyographic pattern of the biceps brachii muscle in young adults with different occlusal characteristics.

    PubMed

    Ferrario, V F; Sforza, C; Serrao, G; Fragnito, N; Grassi, G

    2001-08-01

    To investigate the hypothesis of a functional coupling between the stomatognathic motor apparatus and the muscles of other body districts, as well as between occlusal conditions and neuromuscular performance, two groups of men (age range 20-26 years), with either normal occlusion (14 men) or malocclusion (15 men), sustained with their dominant arm a dumbbell weighing 80% of their maximum while maintaining different jaw positions: mouth open, without dental contact; mouth close, with light dental contact; maximum voluntary clench; maximum voluntary clench on two cotton rolls positioned on the posterior mandibular teeth; maximum voluntary clench on one cotton roll positioned on the right/left-side posterior mandibular teeth. Surface electromyography (EMG) of the biceps brachii muscle was performed, and the endurance time, mean root mean square (rms) potential, and mean median power frequency were computed. The mean potential and median power frequency were also computed for 2-s windows, and values as a function of time were interpolated by a linear regression analysis. Data were compared between groups and trials by using a factorial analysis of variance. The malocclusion group subjects could perform the exercise for a longer time span than the normal occlusion individuals (P < 0.005). During this endurance time their biceps brachii muscles contracted with different patterns: on average, in the malocclusion group they had a larger EMG amplitude (P < 0.005), and a shift of the power spectrum toward lower frequencies (P < 0.005). The factor 'jaw position' was significant only for the endurance time (P < 0.005). In both groups, the longest endurance time was found in the 'clench' trial, while the shortest in the 'right-side bite' trial. In conclusion, a morphologically altered occlusion does not always worsen the muscular performance of other body districts, and the use of occlusal supports (cotton rolls) is not always beneficial.

  13. The influence of prior hamstring injury on lengthening muscle tissue mechanics.

    PubMed

    Silder, Amy; Reeder, Scott B; Thelen, Darryl G

    2010-08-26

    Hamstring strain injuries often occur near the proximal musculotendon junction (MTJ) of the biceps femoris. Post-injury remodeling can involve scar tissue formation, which may alter contraction mechanics and influence re-injury risk. The purpose of this study was to assess the affect of prior hamstring strain injury on muscle tissue displacements and strains during active lengthening contractions. Eleven healthy and eight subjects with prior biceps femoris injuries were tested. All previously injured subjects had since returned to sport and exhibited evidence of residual scarring along the proximal aponeurosis. Subjects performed cyclic knee flexion-extension on an MRI-compatible device using elastic and inertial loads, which induced active shortening and lengthening contractions, respectively. CINE phase-contrast imaging was used to measure tissue velocities within the biceps femoris during these tasks. Numerical integration of the velocity information was used to estimate two-dimensional tissue displacement and strain fields during muscle lengthening. The largest tissue motion was observed along the distal MTJ, with the active lengthening muscle exhibiting significantly greater and more homogeneous tissue displacements. First principal strain magnitudes were largest along the proximal MTJ for both loading conditions. The previously injured subjects exhibited less tissue motion and significantly greater strains near the proximal MTJ. We conclude that localized regions of high tissue strains during active lengthening contractions may predispose the proximal biceps femoris to injury. Furthermore, post-injury remodeling may alter the in-series stiffness seen by muscle tissue and contribute to the relatively larger localized tissue strains near the proximal MTJ, as was observed in this study.

  14. Assessment of the sensory quality and shelf stability of selected Horro beef muscles in Ethiopia.

    PubMed

    Yadata, Melese Abdisa; Werner, Carsten; Tibbo, Markos; Wollny, Clemens B A; Wicke, Michael

    2009-09-01

    The objective of this work was to assess sensory quality and retail life of Horro beef muscles in Ethiopia. Six muscles: M. rhomboideus (RM), M. infraspinatus (IS), M. longissimus lumborum (LL), M. semimembranosus (SM), M. biceps femoris (BF) and M. rectus femoris (RF) were considered. Sensory quality of the muscles was rated by a 9-member trained panel for palatability, tenderness, juiciness, amount of connective tissue (ACT), lean color and surface discoloration and measured by Warner-Bratzler Shear Force (WBSF). Retail life of the six muscles were evaluated for CIE 1976 L(∗)a(∗)b(∗) color values across 6 days. Significant differences (p<0.05) between muscles for all sensory attributes and WBSF were found. Significant L(∗)a(∗)b(∗) color values of muscles and USDA quality grades by retail life were found (p<0.05). Significant correlations (p<0.05 or p<0.01) of key parameters were also identified.

  15. Comparative study of linear and curvilinear ultrasound probes to assess quadriceps rectus femoris muscle mass in healthy subjects and in patients with chronic respiratory disease

    PubMed Central

    Mandal, S; Suh, E; Thompson, A; Connolly, B; Ramsay, M; Harding, R; Puthucheary, Z; Moxham, J; Hart, N

    2016-01-01

    Introduction Ultrasound measurements of rectus femoris cross-sectional area (RFCSA) are clinically useful measurements in chronic obstructive pulmonary disease (COPD) and critically ill patients. Technical considerations as to the type of probe used, which affects image resolution, have limited widespread clinical application. We hypothesised that measurement of RFCSA would be similar with linear and curvilinear probes. Methods Four studies were performed to compare the use of the curvilinear probe in measuring RFCSA. Study 1 investigated agreement of RFCSA measurements using linear and curvilinear probes in healthy subjects, and in patients with chronic respiratory disease. Study 2 investigated the intra-rater and inter-rater agreement using the curvilinear probe. Study 3 investigated the agreement of RFCSA measured from whole and spliced images using the linear probe. Study 4 investigated the applicability of ultrasound in measuring RFCSA during the acute and recovery phases of an exacerbation of COPD. Results Study 1 showed demonstrated no difference in the measurement of RFCSA using the curvilinear and linear probes (308±104 mm2 vs 320±117 mm2, p=0.80; intraclass correlation coefficient (ICC)>0.97). Study 2 demonstrated high intra-rater and inter-rater reliability of RFCSA measurement with ICC>0.95 for both. Study 3 showed that the spliced image from the linear probe was similar to the whole image RFCSA (308±103.5 vs 263±147 mm2, p=0.34; ICC>0.98). Study 4 confirmed the clinical acceptability of using the curvilinear probe during an exacerbation of COPD. There were relationships observed between admission RFCSA and body mass index (r=+0.65, p=0.018), and between RFCSA at admission and physical activity levels at 4 weeks post-hospital discharge (r=+0.75, p=0.006). Conclusions These studies have demonstrated that clinicians can employ whole and spliced images from the linear probe or use images from the curvilinear probe, to measure RFCSA. This will extend

  16. An anatomical study of the proximal hamstring muscle complex to elucidate muscle strains in this region.

    PubMed

    Battermann, N; Appell, H-J; Dargel, J; Koebke, J

    2011-03-01

    Muscle strain injuries are common in sports, and a high incidence is reported for the hamstring muscles, especially in the proximal region, where the long head of the biceps femoris muscle is most frequently affected. To look for some architectural peculiarities, which would make this muscle vulnerable, 101 legs of embalmed human cadavers were dissected and descriptively examined, morphometric data were obtained in the proximal region, and slices of plastinated specimens were microscopically examined. The 3 muscles composing the proximal hamstring complex are partly twisted around each other and possess common fibrous adhesions. Biceps femoris (BF) and semitendinosus (ST) muscles form a common head, to which the ST contributes the majority of fascicles extending 9 cm down from the ischiac tuberosity, thereby attaching to the common tendon at a remarkable pennation angle. The first BF fascicles origin from the common tendon only at 6 cm distance from the ischiac tuberosity. It is concluded that the high incidence of proximal BF strains may be a misinterpretation due to insufficient imaging and the complex architecture. It is suggested that the pennation angle at which the ST inserts to the common tendon makes this muscle especially vulnerable for strains during forced eccentric contractions.

  17. Electromyographic analysis of lower limb muscles during the golf swing performed with three different clubs.

    PubMed

    Marta, Sérgio; Silva, Luís; Vaz, João Rocha; Castro, Maria António; Reinaldo, Gustavo; Pezarat-Correia, Pedro

    2016-01-01

    The aim of this study was to describe and compare the EMG patterns of select lower limb muscles throughout the golf swing, performed with three different clubs, in non-elite middle-aged players. Fourteen golfers performed eight swings each using, in random order, a pitching wedge, 7-iron and 4-iron. Surface electromyography (EMG) was recorded bilaterally from lower limb muscles: tibialis anterior, peroneus longus, gastrocnemius medialis, gastrocnemius lateralis, biceps femoris, semitendinosus, gluteus maximus, vastus medialis, rectus femoris and vastus lateralis. Three-dimensional high-speed video analysis was used to determine the golf swing phases. Results showed that, in average handicap golfers, the highest muscle activation levels occurred during the Forward Swing Phase, with the right semitendinosus and the right biceps femoris muscles producing the highest mean activation levels relative to maximal electromyography (70-76% and 68-73% EMG(MAX), respectively). Significant differences between the pitching wedge and the 4-iron club were found in the activation level of the left semitendinosus, right tibialis anterior, right peroneus longus, right vastus medialis, right rectus femuris and right gastrocnemius muscles. The lower limb muscles showed, in most cases and phases, higher mean values of activation on electromyography when golfers performed shots with a 4-iron club.

  18. Electromyographic analysis of lower limb muscles during the golf swing performed with three different clubs.

    PubMed

    Marta, Sérgio; Silva, Luís; Vaz, João Rocha; Castro, Maria António; Reinaldo, Gustavo; Pezarat-Correia, Pedro

    2016-01-01

    The aim of this study was to describe and compare the EMG patterns of select lower limb muscles throughout the golf swing, performed with three different clubs, in non-elite middle-aged players. Fourteen golfers performed eight swings each using, in random order, a pitching wedge, 7-iron and 4-iron. Surface electromyography (EMG) was recorded bilaterally from lower limb muscles: tibialis anterior, peroneus longus, gastrocnemius medialis, gastrocnemius lateralis, biceps femoris, semitendinosus, gluteus maximus, vastus medialis, rectus femoris and vastus lateralis. Three-dimensional high-speed video analysis was used to determine the golf swing phases. Results showed that, in average handicap golfers, the highest muscle activation levels occurred during the Forward Swing Phase, with the right semitendinosus and the right biceps femoris muscles producing the highest mean activation levels relative to maximal electromyography (70-76% and 68-73% EMG(MAX), respectively). Significant differences between the pitching wedge and the 4-iron club were found in the activation level of the left semitendinosus, right tibialis anterior, right peroneus longus, right vastus medialis, right rectus femuris and right gastrocnemius muscles. The lower limb muscles showed, in most cases and phases, higher mean values of activation on electromyography when golfers performed shots with a 4-iron club. PMID:26197882

  19. Expression profiles of myostatin, myogenin, and Myosin heavy chain in skeletal muscles of two rabbit breeds differing in growth rate.

    PubMed

    Kuang, Liangde; Xie, Xiaohong; Zhang, Xiangyu; Lei, Min; Li, Congyan; Ren, Yongjun; Zheng, Jie; Guo, Zhiqiang; Zhang, Cuixia; Yang, Chao; Zheng, Yucai

    2014-01-01

    The purpose of the present study was to compare mRNA levels of myostatin (MSTN), myogenin (MyoG), and fiber type compositions in terms of myosin heavy chain (MyHC) in skeletal muscles of two rabbit breeds with different body sizes and growth rates. Longissimus dorsi and biceps femoris muscles of 16 Californian rabbits (CW) and 16 Germany great line of ZIKA rabbits (GZ) were collected at the ages of 35d and 84d (slaughter age). The results showed that the live weights of GZ rabbits of 35d and 84d old were approximately 36% and 26% greater than those of CW rabbits, respectively. Quantitative real-time PCR analysis revealed that at the age of 84d GZ rabbits contained significantly lower MSTN mRNA level and higher MyoG mRNA level in both longissimus dorsi and biceps femoris muscles than CW rabbits, and mRNA levels of MSTN and MyoG exhibited opposite changes from the age of 35d to 84d, suggesting that GZ rabbits were subjected to less growth inhibition from MSTN at slaughter age, which occurred most possibly in skeletal muscles. Four types of fiber were identified by real-time PCR in rabbit muscles, with MyHC-1 and MyHC-2D, MyHC-2B were the major types in biceps femoris and longissimus dorsi muscles, respectively. At the age of 84d, GZ rabbits contained greater proportion of MyHC-1 and decreased proportion of MyHC-2D and decreased lactate dehydrogenase activity in biceps femoris than CW rabbits, and the results were exactly opposite in longissimus dorsi, suggesting that GZ rabbits show higher oxidative capacity in biceps femoris muscle than CW rabbits. In conclusion, the trends of mRNA levels of MSTN and fiber types in GZ rabbits' skeletal muscles might be consistent with the putative fast growth characteristic of GZ rabbits compared to CW rabbits.

  20. An analysis on muscle tone of lower limb muscles on flexible flat foot.

    PubMed

    Um, Gi-Mai; Wang, Joong-San; Park, Si-Eun

    2015-10-01

    [Purpose] The aim of this study was to examine differences in the muscle tone and stiffness of leg muscles according to types of flexible flat foot. [Subjects and Methods] For 30 subjects 10 in a normal foot group (NFG), 10 in group with both flexible flat feet (BFFG), and 10 in a group with flexible flat feet on one side (OFFG), myotonometry was used to measure the muscle tone and stiffness of the tibialis anterior muscle (TA), the rectus femoris muscle (RF), the medial gastrocnemius (MG), and the long head of the biceps femoris muscle (BF) of both lower extremities. [Results] In the measurement results, only the stiffness of TA and MG of the NFG and the BFFG showed significant differences. The muscle tone and stiffness were highest in the BFFG, followed by the OFFG and NFG, although the difference was insignificant. In the case of the OFFG, there was no significant difference in muscle tone and stiffness compared to that in the NGF and the BFFG. Furthermore, in the NFG, the non-dominant leg showed greater muscle tone and stiffness than the dominant leg, although the difference was insignificant. [Conclusion] During the relax condition, the flexible flat foot generally showed a greater muscle tone and stiffness of both lower extremities compared to the normal foot. The stiffness was particularly higher in the TA and MG muscles. Therefore, the muscle tone and stiffness of the lower extremity muscles must be considered in the treatment of flat foot.

  1. Fixed Foot Balance Training Increases Rectus Femoris Activation During Landing and Jump Height in Recreationally Active Women

    PubMed Central

    Kean, Crystal O.; Behm, David G.; Young, Warren B.

    2006-01-01

    The objective of this study was to determine the effects of fixed foot and functionally directed balance training on static balance time, muscle activation during landing, vertical jump height and sprint time. Twenty-four recreationally active females were tested pre- and post-training (fixed foot balance training, n= 11, functionally directed balance training, n = 7 and control group, n = 6). Experimental subjects completed either fixed foot or functionally directed balance exercises 4 times/week for 6 weeks. Surface electromyography (EMG) was used to assess preparatory and reactive muscle activity of the rectus femoris (RF), biceps femoris (BF), and the soleus during one- and two-foot landings following a jump. Maximum vertical jump height, static balance and 20-meter sprint times were also examined. The fixed foot balance-training group showed a 33% improvement (p < 0.05) in static balance time and 9% improvement in jump height. Neither type of training improved sprint times. Further analysis revealed significant (p < 0.05) overall (data collapsed over groups and legs) increases in reactive RF activity when landing. Independently, the fixed foot balance group showed a 33% increase in reactive RF activity (p < 0.01). Overall, there was also significantly less reactive co-activation following training (p < 0.05). It appears that fixed foot balance training for recreationally active women may provide greater RF activity when landing and increased countermovement jump height. Key points Balance training increased rectus femoris EMG activity upon landing from a stride. Fixed foot balance training improved countermovement jump height. Neither fixed foot nor functionally directed balance training elicited changes in sprint times. PMID:24198691

  2. Use of B-mode ultrasonography for measuring femoral muscle thickness in dogs

    PubMed Central

    SAKAEDA, Kanako; SHIMIZU, Miki

    2016-01-01

    Assessment of muscle mass is important for evaluating muscle function and rehabilitation outcomes. Ultrasound has recently been successfully used to estimate muscle mass in humans by measuring muscle thickness. This study attempted to standardize procedures for measuring femoral muscle thickness ultrasonographically, as well as quantify the reliability and validity of ultrasound evaluations of muscle thickness compared to measurements made by magnetic resonance imaging (MRI) in dogs. We evaluated the quadriceps femoris (QF), biceps femoris (BF), semitendinosus (ST) and semimembranosus (SM) muscles of 10 clinically healthy Beagle dogs. Scans were taken in 5 different sections divided equally between the greater trochanter and proximal patella. MRI was performed, followed by T1-weighted and contrast-enhanced T1-weighted imaging. Muscle cross-sectional area (CSA) was measured with MRI, and muscle thickness was measured with MRI and ultrasonography. The thickness of the QF, BF and ST muscles as measured by ultrasound at slices 1–3 (from the proximal end to the middle of the femur), 2–4 (middle of the femur) and 2 (more proximal than the middle of the femur), respectively, was correlated with muscle thickness and CSA as measured by MRI. These sites showed a flat interface between muscle and transducer and were situated over belly muscle. No correlation between measurement types was seen in SM muscle. We must confirm this assessment method for various breeds, sizes, ages and muscle pathologies in dogs, thereby confirming that muscle thickness as measured ultrasonographically can reflect muscle function. PMID:26832997

  3. Myositis Ossificans of Rectus Femoris: A Rare Case Report

    PubMed Central

    Srikanth, I Muni; Vishal, Amar; Kiran, K Ravi

    2015-01-01

    Introduction: Myositis ossificans (MO), heterotopic ossification, occurs in muscles and soft tissue. This lesion contains actively proliferating fibroblasts and osteoblasts. It commonly affects vigorous young men and more so among athletes. It occurs as a result of trauma, either acute or chronic and can also arise near joints in neurological disorders. By time of presentation, ossification is extensive and the benign nature of the lesion is usually evident on radiological studies. Most common muscles involved in MO are the flexor muscles of the arm, the hamstrings and quadriceps femoris. Case Report: We present a case of MO with isolated involvement of rectus femoris in mid-thigh and sparing of other three muscles of quadriceps femoris, with no improvement following physiotherapy and medical management requiring surgical excision for better prognosis with no recurrence. Conclusion: MO, a benign lesion, is known to affect the flexors of the arm, the hamstrings, and quadriceps femoris; it must be noted that even individual muscle can also be affected as shown in the above case presentation without involving whole group of muscles. Surgical excision is indicated if non-operative measures are not successful. PMID:27299083

  4. Changes in input-output relations in the corticospinal pathway to the lower limb muscles during robot-assisted passive stepping.

    PubMed

    Kamibayashi, Kiyotaka; Nakajima, Tsuyoshi; Takahashi, Makoto; Nakazawa, Kimitaka

    2011-01-01

    We investigated input (stimulus)-output (response) relations of the corticospinal pathway in the lower limb muscles during passive stepping using a robotic driven gait orthosis. Nine healthy adult subjects passively stepped with 40% body weight unloading (ground stepping) and 100% body weight unloading in the air (air stepping). During passive stepping, the motor evoked potentials (MEPs) of the lower limb muscles elicited by transcranial magnetic stimulation (TMS) were recorded at late-stance, early-, and late-swing phases of 2 stepping conditions. The input-output relation at each phase of the stepping conditions was obtained by increasing stimulus intensity in 5% increments from 40% to 70% of maximal stimulator output. The slopes of input-output relations were steeper at the early-swing phase in the rectus femoris muscle and at the late-stance and late-swing phases in the biceps femoris muscle in both stepping conditions. There were no significant differences in the MEP responses of the rectus femoris and biceps femoris muscles at each phase between the 2 conditions. Low muscle activity was seen at the late-stance phase of ground stepping in the soleus muscle and the MEP amplitude at this phase became larger. The slopes in the tibialis anterior muscle were steep at the early- and late-swing phases of ground stepping. There was a significant difference in the MEPs of the tibialis anterior muscle between the late-swing phases in ground and air stepping. The present study indicates that corticospinal excitability to the lower limb muscles is modulated by sensory inputs elicited by passive stepping.

  5. Tenoscopic Suprapectoral Biceps Tenodesis

    PubMed Central

    Maier, Dirk; Izadpanah, Kaywan; Jaeger, Martin; Ogon, Peter; Südkamp, Norbert P.

    2016-01-01

    Existing arthroscopic techniques of proximal biceps tenodesis may be complicated by difficulty of tendon identification, restoration of length-tension relation, cosmetic deformity, persistent biceps pain, and shoulder stiffness requiring surgical revision in a relevant proportion of cases. In this context, biceps tenoscopy, an emerging discipline of shoulder endoscopy, offers major benefits. Tenoscopy comprises endoscopic treatment of tendons and tendon sheaths. The presented technique of tenoscopic suprapectoral biceps tenodesis (TSBT) substantially facilitates tendon identification and reduces invasiveness by avoidance of unnecessary surgical involvement of the deltoid space and bursa. TSBT enables effective treatment of the biceps tendon and surrounding tissues (biceps tendon sheath, tenosynovium, transverse humeral ligament) being consistently involved in proximal biceps pathologies. The physiological length-tension relation of the musculotendinous unit is reliably maintained. Technically, the procedure of tenodesis is simplified and accelerated by redundancy of tendon exteriorization. The aforementioned benefits of TSBT may lead to superior clinical and cosmetic outcomes and lower incidences of persistent proximal biceps pain and postoperative shoulder stiffness compared with conventional techniques of arthroscopic biceps tenodesis. PMID:27073777

  6. Proximal Rectus Femoris Avulsion Repair.

    PubMed

    Dean, Chase S; Arbeloa-Gutierrez, Lucas; Chahla, Jorge; Pascual-Garrido, Cecilia

    2016-06-01

    Proximal rectus femoris tendon avulsions are rare and occur mostly in male athletes. Currently, the standard of care for complete tendinous avulsions of the direct arm of the rectus femoris is nonoperative treatment. However, surgical repair may be considered in high-level athletes who have a high demand for repetitive hip flexion performed in an explosive manner or in patients in whom nonoperative treatment has failed. The purpose of this technical note is to describe the method for surgical repair of the proximal direct arm of the rectus femoris to its origin at the anterior inferior iliac spine using suture anchors. PMID:27656376

  7. Effects of pre-exhausting the biceps brachii muscle on the performance of the front lat pull-down exercise using different handgrip positions.

    PubMed

    Vilaça-Alves, José; Geraldes, Lurdes; Fernandes, Helder M; Vaz, Luís; Farjalla, Renato; Saavedra, Francisco; Reis, Victor M

    2014-09-29

    The aim of the present study was to investigate the effects of pre-exhaustion (PE) of the biceps brachii muscle (BB) on the number of repetitions and the rate of perceived exertion (RPE) in the front lat pull-down (FLPD) using different handgrip positions. Additionally, the effect of sex and its interaction with performance and the RPE were also examined. The participants were 19 healthy subjects: 8 men (age: 27.13±2.85 years; body height: 180.63±6.65 cm; body mass: 82.05±8.92 kg; and body fat: 14.67±6.09%); and 11 women (age: 28.81±3.68 years; body height: 162.91±6.51 cm; body mass 59.63±6.47 kg; and body fat: 24.11±4.33%). The number of repetitions and the RPE in the FLPD exercise with different handgrip positions, with and without PE of the BB, was documented. The following main significant effects were seen: i) PE of the BB decreased the number of repetitions (p<0.001) and increased the RPE (p<0.001); ii) the narrow handgrip width elicited a higher RPE (p<0.001) and iii) women performed fewer repetitions than men in all FLPD exercise variations (p=0.023). Significant interactions were also observed between: i) PE or sex and the RPE (p=0.024); and ii) PE or handgrip width and the number of repetitions (p<0.001). In conclusion, PE of the BB promotes a decreased performance in the FLPD exercise along with a greater RPE, especially when using a narrow handgrip position.

  8. Strength and muscle activities during the toe-gripping action: comparison of ankle angle in the horizontal plane between the sitting upright and standing positions

    PubMed Central

    Soma, Masayuki; Murata, Shin; Kai, Yoshihiro; Nakae, Hideyuki; Satou, Yousuke

    2016-01-01

    [Purpose] The aim of this study was to investigate whether toe grip strength and muscle activities are affected by the ankle angle in the horizontal plane in the sitting upright and standing positions. [Subjects] The subjects were 16 healthy young women. [Methods] We measured toe grip strength and the maximum voluntary contraction activities of the rectus femoris, biceps femoris, anterior tibialis, and medial head of the gastrocnemius. In addition, we calculated the percent integrated electromyography during foot gripping in 3 different ankle joint positions between the long axis of the foot and the line of progression on the horizontal plane, namely 10° of internal rotation, 0°, and 10° of external rotation. [Results] Two-way analysis of variance revealed significant differences. A significant main effect was observed in the measurement conditions for the percent integrated electromyography of the rectus femoris muscle and long head of the biceps femoris. However, two-way analysis of variance did not reveal any significant difference, and a significant main effect was not observed in toe grip strength. [Conclusion] These findings suggest that exerted toe grip strength is only slightly affected by the ankle angle in the horizontal plane in the sitting upright and standing positions. Therefore, the current measurement positions were shown to be optimal for measurement. PMID:27134399

  9. Immediate effects of kinematic taping on lower extremity muscle tone and stiffness in flexible flat feet

    PubMed Central

    Wang, Joong-San; Um, Gi-Mai; Choi, Jung-Hyun

    2016-01-01

    [Purpose] This study aimed to examine the immediate effects of kinematic taping on the tone and stiffness in the leg muscles of subjects with flexible flat feet. [Subjects and Methods] A total of 30 subjects, 15 in the kinematic taping and 15 in the sham taping group, were administered respective taping interventions. Subsequently, the foot pressure and the tone and stiffness in the tibialis anterior, rectus femoris, medial gastrocnemius, and the long head of the biceps femoris muscles of both the lower extremities were measured. [Results] The foot pressure of the dominant leg significantly decreased in the kinematic taping group. The muscle tone and stiffness in the rectus femoris muscle of the dominant and non-dominant leg, tibialis anterior muscle of the dominant leg, medial gastrocnemius muscle of the non-dominant leg, and the stiffness in the dominant leg significantly decreased. The muscle tone and stiffness generally increased in the sham taping group. However, no significant difference was observed between the 2 groups. [Conclusion] This study demonstrated that kinematic taping on flexible flat feet had positive effects of immediately reducing the abnormally increased foot pressure and the tone and stiffness in the lower extremity muscles. PMID:27190479

  10. Muscle and intensity based hamstring exercise classification in elite female track and field athletes: implications for exercise selection during rehabilitation

    PubMed Central

    Tsaklis, Panagiotis; Malliaropoulos, Nikos; Mendiguchia, Jurdan; Korakakis, Vasileios; Tsapralis, Kyriakos; Pyne, Debasish; Malliaras, Peter

    2015-01-01

    Background Hamstring injuries are common in many sports, including track and field. Strains occur in different parts of the hamstring muscle but very little is known about whether common hamstring loading exercises specifically load different hamstring components. The purpose of this study was to investigate muscle activation of different components of the hamstring muscle during common hamstring loading exercises. Methods Twenty elite female track and field athletes were recruited into this study, which had a single-sample, repeated-measures design. Each athlete performed ten hamstring loading exercises, and an electromyogram (EMG) was recorded from the biceps femoris and semitendinosus components of the hamstring. Hamstring EMG during maximal voluntary isometric contraction (MVIC) was used to normalize the mean data across ten repetitions of each exercise. An electrogoniometer synchronized to the EMG was used to determine whether peak EMG activity occurred during muscle-tendon unit lengthening, shortening, or no change in length. Mean EMG values were compared between the two recording sites for each exercise using the Student’s t-test. Results The lunge, dead lift, and kettle swings were low intensity (<50% MVIC) and all showed higher EMG activity for semitendinosus than for biceps femoris. Bridge was low but approaching medium intensity, and the TRX, hamstring bridge, and hamstring curl were all medium intensity exercises (≥50% or <80% MVIC). The Nordic, fitball, and slide leg exercises were all high intensity exercises. Only the fitball exercise showed higher EMG activity in the biceps femoris compared with the semitendinosus. Only lunge and kettle swings showed peak EMG in the muscle-tendon unit lengthening phase and both these exercises involved faster speed. Conclusion Some exercises selectively activated the lateral and medial distal hamstrings. Low, medium, and high intensity exercises were demonstrated. This information enables the clinician, strength

  11. Comparison of trunk and hip muscle activity during different degrees of lumbar and hip extension.

    PubMed

    Kim, Sang-Min; Yoo, Won-Gyu

    2015-09-01

    [Purpose] This study compared the activity of trunk and hip muscles during different degrees of lumbar and hip extension. [Subjects] The study enrolled 18 participants. [Methods] Two exercises (hip and lumbar extension) and two ranges (180° and <180°) were studied. [Results] Differences in degree of extension affected the percentage maximal voluntary isometric contraction of the lumbar erector spinae and biceps femoris muscles, with significantly higher average values at >180° than at 180° lumbar extension. No significant differences were found in gluteus maximus activity according to exercise type or range. [Conclusion] Hip extension may be more effective and safer for lumbar rehabilitation than lumbar extension.

  12. The effects of horseback riding simulator exercises on the muscle activity of the lower extremities according to changes in arm posture

    PubMed Central

    Park, Jungseo; Lee, Sangyong; Lee, Daehee

    2015-01-01

    [Purpose] This study aimed to determine the effects of horseback riding simulator exercise on the muscle activities of the lower extremities according to changes in arm posture. [Subjects] The subjects of this study were 30 normal adult males and females. [Methods] The horseback riding simulator exercise used a horseback riding simulator device; two arm postures were used, posture 1 (holding the handle of the device) and posture 2 (crossing both arms, with both hands on the shoulders). Electromyography was used to compare the muscle activities of the rectus femoris, biceps femoris, and hip adductors in the lower extremities. [Results] Posture 2 had significantly higher muscle activity than posture 1. [Conclusion] Posture 2, which entailed crossing both arms with both hands on the shoulders, was an effective intervention for improved muscle activity in the hip adductors. PMID:26504280

  13. The effect of temperature on apoptosis and adipogenesis on skeletal muscle satellite cells derived from different muscle types.

    PubMed

    Harding, Rachel L; Clark, Daniel L; Halevy, Orna; Coy, Cynthia S; Yahav, Shlomo; Velleman, Sandra G

    2015-09-01

    Satellite cells are multipotential stem cells that mediate postnatal muscle growth and respond differently to temperature based upon aerobic versus anaerobic fiber-type origin. The objective of this study was to determine how temperatures below and above the control, 38°C, affect the fate of satellite cells isolated from the anaerobic pectoralis major (p. major) or mixed fiber biceps femoris (b. femoris). At all sampling times, p. major and b. femoris cells accumulated less lipid when incubated at low temperatures and more lipid at elevated temperatures compared to the control. Satellite cells isolated from the p. major were more sensitive to temperature as they accumulated more lipid at elevated temperatures compared to b. femoris cells. Expression of adipogenic genes, CCAAT/enhancer-binding protein β (C/EBPβ) and proliferator-activated receptor gamma (PPARγ) were different within satellite cells isolated from the p. major or b. femoris. At 72 h of proliferation, C/EBPβ expression increased with increasing temperature in both cell types, while PPARγ expression decreased with increasing temperature in p. major satellite cells. At 48 h of differentiation, both C/EBPβ and PPARγ expression increased in the p. major and decreased in the b. femoris, with increasing temperature. Flow cytometry measured apoptotic markers for early apoptosis (Annexin-V-PE) or late apoptosis (7-AAD), showing less than 1% of apoptotic satellite cells throughout all experimental conditions, therefore, apoptosis was considered biologically not significant. The results support that anaerobic p. major satellite cells are more predisposed to adipogenic conversion than aerobic b. femoris cells when thermally challenged.

  14. The effect of temperature on apoptosis and adipogenesis on skeletal muscle satellite cells derived from different muscle types

    PubMed Central

    Harding, Rachel L; Clark, Daniel L; Halevy, Orna; Coy, Cynthia S; Yahav, Shlomo; Velleman, Sandra G

    2015-01-01

    Satellite cells are multipotential stem cells that mediate postnatal muscle growth and respond differently to temperature based upon aerobic versus anaerobic fiber-type origin. The objective of this study was to determine how temperatures below and above the control, 38°C, affect the fate of satellite cells isolated from the anaerobic pectoralis major (p. major) or mixed fiber biceps femoris (b. femoris). At all sampling times, p. major and b. femoris cells accumulated less lipid when incubated at low temperatures and more lipid at elevated temperatures compared to the control. Satellite cells isolated from the p. major were more sensitive to temperature as they accumulated more lipid at elevated temperatures compared to b. femoris cells. Expression of adipogenic genes, CCAAT/enhancer-binding protein β (C/EBPβ) and proliferator-activated receptor gamma (PPARγ) were different within satellite cells isolated from the p. major or b. femoris. At 72 h of proliferation, C/EBPβ expression increased with increasing temperature in both cell types, while PPARγ expression decreased with increasing temperature in p. major satellite cells. At 48 h of differentiation, both C/EBPβ and PPARγ expression increased in the p. major and decreased in the b. femoris, with increasing temperature. Flow cytometry measured apoptotic markers for early apoptosis (Annexin-V-PE) or late apoptosis (7-AAD), showing less than 1% of apoptotic satellite cells throughout all experimental conditions, therefore, apoptosis was considered biologically not significant. The results support that anaerobic p. major satellite cells are more predisposed to adipogenic conversion than aerobic b. femoris cells when thermally challenged. PMID:26341996

  15. Biceps Tenotomy Versus Tenodesis.

    PubMed

    Patel, Kushal V; Bravman, Jonathan; Vidal, Armando; Chrisman, Ashley; McCarty, Eric

    2016-01-01

    Long head biceps tendon is a common cause of anterior shoulder pain. Failure of conservative treatment may warrant surgical intervention. Surgical treatment involves long head biceps tenotomy or tenodesis. Several different techniques have been described for biceps tenodesis, including arthroscopic versus open and suprapectoral versus subpectoral. Most studies comparing tenodesis to tenotomy are limited by the level of evidence and confounding factors, such as concomitant rotator cuff tear. Many studies demonstrate similar outcomes for both procedures. Surgeon preference is likely more influential in choosing between tenotomy and tenodesis. Higher-powered studies are necessary to elucidate any differences in outcomes if present.

  16. Biceps Tenotomy Versus Tenodesis.

    PubMed

    Patel, Kushal V; Bravman, Jonathan; Vidal, Armando; Chrisman, Ashley; McCarty, Eric

    2016-01-01

    Long head biceps tendon is a common cause of anterior shoulder pain. Failure of conservative treatment may warrant surgical intervention. Surgical treatment involves long head biceps tenotomy or tenodesis. Several different techniques have been described for biceps tenodesis, including arthroscopic versus open and suprapectoral versus subpectoral. Most studies comparing tenodesis to tenotomy are limited by the level of evidence and confounding factors, such as concomitant rotator cuff tear. Many studies demonstrate similar outcomes for both procedures. Surgeon preference is likely more influential in choosing between tenotomy and tenodesis. Higher-powered studies are necessary to elucidate any differences in outcomes if present. PMID:26614471

  17. Repair of rectus femoris rupture with LARS ligament.

    PubMed

    Taylor, Clare; Yarlagadda, Rathan; Keenan, Jonathan

    2012-03-20

    The rectus femoris muscle is the most frequently involved quadriceps muscle in strain pathologies. The majority of quadriceps muscle belly injuries can be successfully treated conservatively and even significant tears in the less active and older population, non-operative management is a reasonable option. The authors report the delayed presentation of a 17-year-old male who sustained an injury to his rectus femoris muscle belly while playing football. This young patient did not recover the functional outcome required to get back to running and participating in sport despite 15 months of physiotherapy and non-operative management. Operative treatment using the ligament augmentation and reconstruction system ligament to augment Kessler repair allowed immediate full passive flexion of the knee and an early graduated physiotherapy programme. Our patient was able to return to running and his previous level of sport without any restrictions.

  18. Physical, chemical, histological and palatability characteristics of muscles from three breed-types of cattle at different times-on-feed.

    PubMed

    McKeith, F K; Savell, J W; Smith, G C; Dutson, T R; Carpenter, Z L

    1985-01-01

    Forty-five steers (9-12 months of age) of Angus (n =15), Brahman (n = 15) and Brahman × Angus (n = 15) breed-types were fed a high-energy diet and then slaughtered after 0, 112 or 224 days of feeding. At 7 days post mortem, the M. longissimus and M. biceps femoris were removed from the left side of each carcass and steaks were obtained for determination of sensory panel ratings, Warner-Bratzler shear force, sarcomere length, collagen content and collagen solubility. Tenderness ratings of steaks from the M. longissimus and M. biceps femoris from Angus were generally higher than ratings for steaks from Brahman or Brahman × Angus steers. Steaks from Brahman × Angus received higher tenderness ratings than steaks from Brahman steers in only a few comparisons. The three breed-types of cattle responded to time-on-feed differently; Brahman cattle needed to have been fed longer than Angus cattle to produce equally tender beef. With increased time-on-feed, M. longissimus tenderness increased for all breed-types, but M. biceps femoris tenderness was not related to time-on-feed. Few significant differences were observed among breed-types and among time-on-feed periods for collagen content or collagen solubility. Tenderness differences were closely correlated with the contractile state of the muscle which, in turn, was associated with weight, subcutaneous fat thickness and temperature decline of the carcass. PMID:22056075

  19. Physical, chemical, histological and palatability characteristics of muscles from three breed-types of cattle at different times-on-feed.

    PubMed

    McKeith, F K; Savell, J W; Smith, G C; Dutson, T R; Carpenter, Z L

    1985-01-01

    Forty-five steers (9-12 months of age) of Angus (n =15), Brahman (n = 15) and Brahman × Angus (n = 15) breed-types were fed a high-energy diet and then slaughtered after 0, 112 or 224 days of feeding. At 7 days post mortem, the M. longissimus and M. biceps femoris were removed from the left side of each carcass and steaks were obtained for determination of sensory panel ratings, Warner-Bratzler shear force, sarcomere length, collagen content and collagen solubility. Tenderness ratings of steaks from the M. longissimus and M. biceps femoris from Angus were generally higher than ratings for steaks from Brahman or Brahman × Angus steers. Steaks from Brahman × Angus received higher tenderness ratings than steaks from Brahman steers in only a few comparisons. The three breed-types of cattle responded to time-on-feed differently; Brahman cattle needed to have been fed longer than Angus cattle to produce equally tender beef. With increased time-on-feed, M. longissimus tenderness increased for all breed-types, but M. biceps femoris tenderness was not related to time-on-feed. Few significant differences were observed among breed-types and among time-on-feed periods for collagen content or collagen solubility. Tenderness differences were closely correlated with the contractile state of the muscle which, in turn, was associated with weight, subcutaneous fat thickness and temperature decline of the carcass.

  20. Characteristics of lower limb muscle activity during upper limb elevation in badminton players

    PubMed Central

    Masu, Yujiro; Nagai, Masanori

    2016-01-01

    [Purpose] To clarify the characteristics of postural control in badminton players by examining their lower-limb muscle activity during upper-limb elevation. [Subjects and Methods] Fourteen badminton players and 14 non-players were studied. The subjects were instructed to perform an upper-limb elevation task in order to measure the activities of the biceps femoris and biceps brachii. [Results] When elevating the dominant hand, the mean biceps femoris integrated electromyogram showed markedly higher values in the player group, for the contralateral compared with the ipsilateral leg. Similarly, when elevating the dominant hand, the difference in the maximum integrated electromyogram response time between the ipsilateral and contralateral legs was significantly smaller in the players compared with non-players. [Conclusion] It may be possible to reduce the time needed to elevate the dominant hand by shifting lower-limb activity from the ipsilateral to the contralateral leg more quickly, while increasing the rate of rise in contralateral leg muscle activity. PMID:27799681

  1. Effects of postmortem aging and USDA quality grade on Warner-Bratzler shear force values of seventeen individual beef muscles.

    PubMed

    Gruber, S L; Tatum, J D; Scanga, J A; Chapman, P L; Smith, G C; Belk, K E

    2006-12-01

    Forty USDA Select and 40 upper two-thirds USDA Choice beef carcasses were used to determine the effects of postmortem aging on tenderness of 17 individual beef muscles. Biceps femoris-long head, complexus, gluteus medius, infraspinatus, longissimus dorsi, psoas major, rectus femoris, semimembranosus, semitendinosus, serratus ventralis, spinalis dorsi, supraspinatus, tensor fasciae latae, teres major, triceps brachii-long head, vastus lateralis, and vastus medialis muscles were removed from each carcass. Seven steaks (2.54-cm thick) were cut from every muscle, and each steak was assigned to one of the following postmortem aging periods: 2, 4, 6, 10, 14, 21, or 28 d postmortem. After completion of the designated aging period, steaks were removed from storage (2 degrees C, never frozen), cooked to a peak internal temperature of 71 degrees C, and evaluated using Warner-Bratzler shear force (WBSF). Analysis of WBSF revealed a 3-way interaction (P = 0.004) among individual muscle, USDA quality grade, and postmortem aging period. With the exception of the Select teres major, WBSF of all muscles (both quality grades) decreased with increasing time of postmortem storage. Nonlinear regression was used to characterize the extent (aging response) and rate of decrease in WBSF from 2 through 28 d postmortem for each muscle within each quality grade. In general, WBSF of upper two-thirds Choice muscles decreased more rapidly from 2 to 10 d postmortem than did corresponding Select muscles. Muscles that had greater aging responses generally had greater 2-d WBSF values. The upper two-thirds Choice psoas major, serratus ventralis, and vastus lateralis muscles required similar aging times to complete a majority of the aging response (< or =0.1 kg of aging response remaining) compared with analogous Select muscles. The upper two-thirds Choice complexus, gluteus medius, semitendinosus, triceps brachii-long head, and vastus medialis muscles required 4 to 6 d less time to complete a

  2. Altered development and protein metabolism in skeletal muscles of broiler chickens (Gallus gallus domesticus) by corticosterone.

    PubMed

    Dong, H; Lin, H; Jiao, H C; Song, Z G; Zhao, J P; Jiang, K J

    2007-05-01

    Two trials were conducted to investigate the effect of corticosterone (CORT) on protein metabolism and the amino acid composition in muscle tissues of broiler chickens (Gallus gallus domesticus). In Trial 1, two groups of 30 broiler chickens were subjected to control or CORT treatment (30 mg/kg diet) from 28 to 39 days of age. In Trial 2, three groups of chickens of 28 days of age were randomly subjected to one of the following treatments for 7 days: CORT (30 mg/kg diet), pair-fed (maintaining the same feed intake as CORT treatment) and control treatments. The body mass gain and feed efficiency was significantly decreased by CORT treatment, while the food intake was decreased. The breast and thigh masses (% body mass) were significantly suppressed by CORT treatment, while the abdominal fat and liver masses (%) were obviously increased. The plasma levels of glucose, urate and total amino acid were significantly elevated by CORT treatment. The capacity for protein synthesis, estimated by RNA:protein ratio, were significantly suppressed by CORT in M. pectoralis major and M. biceps femoris. The 3-methylhistidine concentrations were significantly increased in both M. pectoralis major and M. biceps femoris of CORT chickens, compared to control but not the pair-fed chickens. The amino acid composition of M. pectoralis major and M. biceps femoris was not significantly affected by CORT treatment. In conclusion, the arrested growth in skeletal muscles induced by CORT administration has tissue specificity. The CORT treatment retards the growth of skeletal muscle by suppressed protein synthesis and augmented protein catabolism.

  3. Comparison of Estimated and Measured Muscle Activity During Inclined Walking.

    PubMed

    Alexander, Nathalie; Schwameder, Hermann

    2016-04-01

    While inclined walking is a frequent daily activity, muscle forces during this activity have rarely been examined. Musculoskeletal models are commonly used to estimate internal forces in healthy populations, but these require a priori validation. The aim of this study was to compare estimated muscle activity using a musculoskeletal model with measured EMG data during inclined walking. Ten healthy male participants walked at different inclinations of 0°, ± 6°, ± 12°, and ± 18° on a ramp equipped with 2 force plates. Kinematics, kinetics, and muscle activity of the musculus (m.) biceps femoris, m. rectus femoris, m. vastus lateralis, m. tibialis anterior, and m. gastrocnemius lateralis were recorded. Agreement between estimated and measured muscle activity was determined via correlation coefficients, mean absolute errors, and trend analysis. Correlation coefficients between estimated and measured muscle activity for approximately 69% of the conditions were above 0.7. Mean absolute errors were rather high with only approximately 38% being ≤ 30%. Trend analysis revealed similar estimated and measured muscle activities for all muscles and tasks (uphill and downhill walking), except m. tibialis anterior during uphill walking. This model can be used for further analysis in similar groups of participants.

  4. Lower muscle co-contraction in flutter kicking for competitive swimmers.

    PubMed

    Matsuda, Yuji; Hirano, Masami; Yamada, Yosuke; Ikuta, Yasushi; Nomura, Teruo; Tanaka, Hiroaki; Oda, Shingo

    2016-02-01

    The purpose of this study was to examine the difference in muscle activation pattern and co-contraction of the rectus and biceps femoris in flutter-kick swimming between competitive and recreational swimmers, to better understand the mechanism of repetitive kicking movements during swimming. Ten competitive and 10 recreational swimmers swam using flutter kicks at three different velocities (100%, 90%, and 80% of their maximal velocity) in a swimming flume. Surface electromyographic signals (EMG) were obtained from the rectus (RF) and biceps femoris (BF), and lower limb kinematic data were obtained at the same time. The beginning and ending of one kick cycle was defined as when the right lateral malleolus reached its highest position in the vertical axis. The offset timing of muscle activation of RF in the recreational swimmers was significantly later at all velocities than in the competitive swimmers (47-48% and 26-33% of kick time of one cycle for recreational and competitive swimmers, respectively), although the kinematic data and other activation timing of RF and BF did not differ between groups. A higher integrated EMG of RF during hip extension and knee extension induced a higher level of muscle co-contraction between RF and BF in the recreational swimmers. These results suggest that long-term competitive swimming training can induce an effective muscle activation pattern in the upper legs.

  5. Sonography of the accessory head of the biceps brachii.

    PubMed

    Lutterbach-Penna, Ricardo Augusto; Brigido, Monica Kalume; Robertson, Brian; Kim, Sung Moon; Jacobson, Jon A; Fessell, David P

    2014-10-01

    Anatomic variations in the anterior aspect of the shoulder, such as an accessory head of the biceps brachii muscle, are not uncommon. The magnetic resonance imaging and arthroscopic appearance of the accessory head of the biceps brachii has been recently described. This series demonstrates the sonographic appearance of the accessory head of the biceps brachii in the bicipital groove. It is an asymptomatic, flat, echogenic structure with average measurements of 7.7 × 1.2 mm in cross section. Knowledge of this anatomic variant can avoid the misdiagnosis of a longitudinal split tear and improve the accuracy of sonography.

  6. Rupture of the biceps tendon after arthroscopic thermal capsulorrhaphy.

    PubMed

    Hanypsiak, Bryan T; Faulks, Craig; Fine, Kenneth; Malin, Edward; Shaffer, Benjamin; Connell, Marc

    2004-07-01

    The use of thermal energy in the shoulder to tighten capsular tissues through collagen denaturation is well established. Although reported complication rates are low, the natural history of thermal manipulation to both target and collateral tissue is poorly defined. We report two cases of biceps tendon rupture after arthroscopic capsular shrinkage. Both patients were young, athletic men with normal long head biceps tendons at the time of surgery. Each patient experienced a complete tear of the long head with distal muscle retraction, resulting in a "Popeye" deformity, at 3 months postoperatively. One patient elected further surgery with biceps tenodesis. Both patients have returned to their athletic activities with minimal functional deficits.

  7. Muscle Activation Differs between Three Different Knee Joint-Angle Positions during a Maximal Isometric Back Squat Exercise

    PubMed Central

    Jarbas da Silva, Josinaldo; Jon Schoenfeld, Brad; Nardi, Priscyla Silva Monteiro; Pecoraro, Silvio Luis; D'Andréa Greve, Julia Maria; Hartigan, Erin

    2016-01-01

    The purpose of this study was to compare muscle activation of the lower limb muscles when performing a maximal isometric back squat exercise over three different positions. Fifteen young, healthy, resistance-trained men performed an isometric back squat at three knee joint angles (20°, 90°, and 140°) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), and gluteus maximus (GM). In general, muscle activity was the highest at 90° for the three quadriceps muscles, yet differences in muscle activation between knee angles were muscle specific. Activity of the GM was significantly greater at 20° and 90° compared to 140°. The BF and ST displayed similar activation at all joint angles. In conclusion, knee position alters muscles activation of the quadriceps and gluteus maximus muscles. An isometric back squat at 90° generates the highest overall muscle activation, yet an isometric back squat at 140° generates the lowest overall muscle activation of the VL and GM only. PMID:27504484

  8. A comparison of the moment arms of pelvic limb muscles in horses bred for acceleration (Quarter Horse) and endurance (Arab)

    PubMed Central

    Crook, T C; Cruickshank, S E; McGowan, C M; Stubbs, N; Wilson, A M; Hodson-Tole, E; Payne, R C

    2010-01-01

    Selective breeding for performance has resulted in distinct breeds of horse, such as the Quarter Horse (bred for acceleration) and the Arab (bred for endurance). Rapid acceleration, seen during Quarter Horse racing, requires fast powerful muscular contraction and the generation of large joint torques, particularly by the hind limb muscles. This study compared hind limb moment arm lengths in the Quarter Horse and Arab. We hypothesized that Quarter Horse hind limb extensor muscles would have longer moment arms when compared to the Arab, conferring a greater potential for torque generation at the hip, stifle and tarsus during limb extension. Six Quarter Horse and six Arab hind limbs were dissected to determine muscle moment arm lengths for the following muscles: gluteus medius, biceps femoris, semitendinosus, vastus lateralis, gastrocnemius (medialis and lateralis) and tibialis cranialis. The moment arms of biceps femoris (acting at the hip) and gastrocnemius lateralis (acting at the stifle) were significantly longer in the Quarter Horse, although the length of the remaining muscle moment arms were similar in both breeds of horse. All the Quarter Horse muscles were capable of generating greater muscle moments owing to their greater physiological cross-sectional area (PCSA) and therefore greater isometric force potential, which suggests that PCSA is a better determinant of muscle torque than moment arm length in these two breeds of horse. With the exception of gastrocnemius and tibialis cranialis, the observed muscle fascicle length to moment arm ratio (MFL : MA ratio) was greater for the Arab horse muscles. It appears that the Arab muscles have the potential to operate at slower velocities of contraction and hence generate greater force outputs when compared to the Quarter Horse muscles working over a similar range of joint motion; this would indicate that Arab hind limb muscles are optimized to function at maximum economy rather than maximum power output. PMID

  9. A comparison of the moment arms of pelvic limb muscles in horses bred for acceleration (Quarter Horse) and endurance (Arab).

    PubMed

    Crook, T C; Cruickshank, S E; McGowan, C M; Stubbs, N; Wilson, A M; Hodson-Tole, E; Payne, R C

    2010-07-01

    Selective breeding for performance has resulted in distinct breeds of horse, such as the Quarter Horse (bred for acceleration) and the Arab (bred for endurance). Rapid acceleration, seen during Quarter Horse racing, requires fast powerful muscular contraction and the generation of large joint torques, particularly by the hind limb muscles. This study compared hind limb moment arm lengths in the Quarter Horse and Arab. We hypothesized that Quarter Horse hind limb extensor muscles would have longer moment arms when compared to the Arab, conferring a greater potential for torque generation at the hip, stifle and tarsus during limb extension. Six Quarter Horse and six Arab hind limbs were dissected to determine muscle moment arm lengths for the following muscles: gluteus medius, biceps femoris, semitendinosus, vastus lateralis, gastrocnemius (medialis and lateralis) and tibialis cranialis. The moment arms of biceps femoris (acting at the hip) and gastrocnemius lateralis (acting at the stifle) were significantly longer in the Quarter Horse, although the length of the remaining muscle moment arms were similar in both breeds of horse. All the Quarter Horse muscles were capable of generating greater muscle moments owing to their greater physiological cross-sectional area (PCSA) and therefore greater isometric force potential, which suggests that PCSA is a better determinant of muscle torque than moment arm length in these two breeds of horse. With the exception of gastrocnemius and tibialis cranialis, the observed muscle fascicle length to moment arm ratio (MFL : MA ratio) was greater for the Arab horse muscles. It appears that the Arab muscles have the potential to operate at slower velocities of contraction and hence generate greater force outputs when compared to the Quarter Horse muscles working over a similar range of joint motion; this would indicate that Arab hind limb muscles are optimized to function at maximum economy rather than maximum power output.

  10. 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.

  11. Chemical composition, quality and histochemical characteristics of individual dromedary camel (Camelus dromedarius) muscles.

    PubMed

    Kadim, I T; Al-Karousi, A; Mahgoub, O; Al-Marzooqi, W; Khalaf, S K; Al-Maqbali, R S; Al-Sinani, S S H; Raiymbek, G

    2013-03-01

    This study characterized the chemical composition, quality and histological traits of six muscles from 10 dromedary carcasses. There were significant differences in moisture, fat, protein, mineral, saturated and unsaturated fatty acid contents between muscles. The longissimus thoracis (LT) had the highest cooking loss (33.5%) and triceps brachii (TB) the lowest (29.2%). The shear force value of semitendinosus (ST), semimembranosus (SM) and biceps femoris (BF) were significantly higher than infraspinatus (IS), TB and LT. The LT had significantly higher values for L*, a*, b* than ST. The SM had the lowest MFI (65.3), while IS had the highest value (75.8). The ST significantly had the highest and lowest proportions of Type I and Type IIA muscle fibers, respectively than other muscles. This study indicated that composition, quality, and histochemical parameters varied among camel muscles and the knowledge of this variation allows for better marketing and processing of camel meat. PMID:23273465

  12. Three-layered architecture of the popliteal fascia that acts as a kinetic retinaculum for the hamstring muscles.

    PubMed

    Satoh, Masahiro; Yoshino, Hiroyuki; Fujimura, Akira; Hitomi, Jiro; Isogai, Sumio

    2016-09-01

    When patients report pain in the popliteal fossa upon knee extension, the pain is usually localized in the lower region of the popliteal fossa. However, some patients complain of pain in the upper region of the popliteal fossa as the knee is flexed, which motivated us to examine the role of the popliteal fascia as the retinaculum of the hamstring muscles. Thirty-four thighs from 19 Japanese cadavers were dissected. The popliteal fascia was defined as the single aponeurotic sheet covering the popliteal fossa. We found that the fascia acted as a three-layered retinaculum for the flexor muscles of the thigh and provided a secure route for neurovascular structures to the lower leg in any kinetic position of the knee joint. The superficial layer of the popliteal fascia covering the thigh was strongly interwoven with the epimysium of biceps femoris along its lateral aspect and with that of the semimembranosus along its medial aspect, ensuring that the flexor muscles remained in their correct positions. The intermediate layer arose from the medial side of biceps femoris and merged medially with the superficial layer. The profound layer stretched transversely between the biceps femoris and the semimembranosus. Moreover, we investigated the nerve distribution in the popliteal fascia using Sihler's staining and whole-mount immunostaining for neurofilaments. The three-layered fascia was constantly innervated by branches from the posterior femoral cutaneous or saphenous nerve. The nerves were closely related and distributed to densely packed collagen fibers in the superficial layer as free or encapsulated nerve endings, suggesting that the fascia is involved in pain in the upper region of the popliteal fossa.

  13. A 3-Dimensional Anatomic Study of the Distal Biceps Tendon

    PubMed Central

    Walton, Christine; Li, Zhi; Pennings, Amanda; Agur, Anne; Elmaraghy, Amr

    2015-01-01

    Background Complete rupture of the distal biceps tendon from its osseous attachment is most often treated with operative intervention. Knowledge of the overall tendon morphology as well as the orientation of the collagenous fibers throughout the musculotendinous junction are key to intraoperative decision making and surgical technique in both the acute and chronic setting. Unfortunately, there is little information available in the literature. Purpose To comprehensively describe the morphology of the distal biceps tendon. Study Design Descriptive laboratory study. Methods The distal biceps terminal musculature, musculotendinous junction, and tendon were digitized in 10 cadaveric specimens and data reconstructed using 3-dimensional modeling. Results The average length, width, and thickness of the external distal biceps tendon were found to be 63.0, 6.0, and 3.0 mm, respectively. A unique expansion of the tendon fibers within the distal muscle was characterized, creating a thick collagenous network along the central component between the long and short heads. Conclusion This study documents the morphologic parameters of the native distal biceps tendon. Reconstruction may be necessary, especially in chronic distal biceps tendon ruptures, if the remaining tendon morphology is significantly compromised compared with the native distal biceps tendon. Knowledge of normal anatomical distal biceps tendon parameters may also guide the selection of a substitute graft with similar morphological characteristics. Clinical Relevance A thorough description of distal biceps tendon morphology is important to guide intraoperative decision making between primary repair and reconstruction and to better select the most appropriate graft. The detailed description of the tendinous expansion into the muscle may provide insight into better graft-weaving and suture-grasping techniques to maximize proximal graft incorporation. PMID:26665092

  14. Orientation of tendons in vivo with active and passive knee muscles.

    PubMed

    Aalbersberg, Sietske; Kingma, Idsart; Ronsky, Janet L; Frayne, Richard; van Dieën, Jaap H

    2005-09-01

    Tendon orientations in knee models are often taken from cadaver studies. The aim of this study was to investigate the effect of muscle activation on tendon orientation in vivo. Magnetic resonance imaging (MRI) images of the knee were made during relaxation and isometric knee extensions and flexions with 0 degrees , 15 degrees and 30 degrees of knee joint flexion. For six tendons, the orientation angles in sagittal and frontal plane were calculated. In the sagittal plane, muscle activation pulled the patellar tendon to a more vertical orientation and the semitendinosus and sartorius tendons to a more posterior orientation. In the frontal plane, the semitendinosus had a less lateral orientation, the biceps femoris a more medial orientation and the patellar tendon less medial orientation in loaded compared to unloaded conditions. The knee joint angle also influenced the tendon orientations. In the sagittal plane, the patellar tendon had a more anterior orientation near full extension and the biceps femoris had an anterior orientation with 0 degrees and 15 degrees flexions and neutral with 30 degrees flexions. Within 0 degrees to 30 degrees of flexion, the biceps femoris cannot produce a posterior shear force and the anterior angle of the patellar tendon is always larger than the hamstring tendons. Therefore, co-contraction of the hamstring and quadriceps is unlikely to reduce anterior shear forces in knee angles up to 30 degrees . Finally, inter-individual variation in tendon angles was large. This suggests that the amount of shear force produced and the potential to counteract shear forces by co-contraction is subject-specific. PMID:16023464

  15. Failure of distal biceps repair by gapping

    PubMed Central

    Copas, David; Watts, Adam C

    2016-01-01

    Background We describe the clinical, radiological and surgical findings of failed distal biceps repair by gapping and report the functional outcomes following revision repair. Methods A retrospective review of five consecutive patients was conducted. Patients presented with radial-sided forearm pain after their distal biceps fixation. All patients had less than 5 cm of retraction of the biceps muscle belly, a palpable tendon although the manoeuvre was painful with weakness on resisted supination. Flexed abducted supinated magnetic resonance imaging (FABS MRI) showed a gap between the distal end of the tendon and the footprint on the radial tuberosity. Results Mean FEA score at presentation was 44/100 (35 to 49). Mean time to re-operation was 18 months (range 4 months to 36 months). At revision, the distal end of the tendon was retracted and not making contact with the bone. All cases were revised to an in-bone endobutton repair. Mean postoperative Functional Elbow Assessment (FEA) scores undertaken at a mean of 14 months (range 5 months to 22 months) after revision improved to 95/100 (90 to 100). Conclusions Patients presenting with persistent radial sided forearm pain and weakness on provocative testing after distal biceps repair with a seemingly intact repair should be investigated with FABS MRI to look for evidence of failure of repair by gapping. Revision repair with an anatomic in-bone technique can lead to good results. PMID:27583018

  16. A comparative study of the electromyographic activities of lower extremity muscles during level walking and Pedalo riding

    PubMed Central

    Lee, DongGeon; Kim, YouJeong; Yun, JiHyeon; Jung, MiHye; Lee, GyuChang

    2016-01-01

    [Purpose] To analyze the electromyographic (EMG) activities of several lower extremity muscles during ground walking and pedaling using the Pedalo Reha-Bar device. [Subjects and Methods] Fifteen healthy adults aged 20–29 year participated in this study. The subjects’ surface EMG signals while walking and Pedalo Reha-Bar riding were recorded. The subjects performed 20 steps on flat ground and 20 cycles on the Pedalo Reha-Bar. During the tasks, EMG signals of the rectus femoris, biceps femoris, tibialis anterior, soleus, and gastrocnemius within a 20-second period were recorded. The mean EMG signals within the 10 seconds from 6 to 15 seconds were used for the data analysis. [Results] There was a significant increase in the bilateral use of the rectus femoris and a significant decrease in the use of the left tibialis anterior and left soleus in pedaling using the Pedalo Reha-Bar device compared to ground walking. [Conclusion] Level walking and the Pedalo Reha-Bar riding utilize different types of muscles activities. These results suggest that Pedalo Reha-Bar riding may be used for neuromuscular activation, especially of the rectus femoris. PMID:27313354

  17. Remote Dose-Dependent Effects of Dry Needling at Distant Myofascial Trigger Spots of Rabbit Skeletal Muscles on Reduction of Substance P Levels of Proximal Muscle and Spinal Cords

    PubMed Central

    Hsieh, Yueh-Ling; Liu, Szu-Yu; Hong, Chang-Zern

    2014-01-01

    Background. Dry needling at distant myofascial trigger points is an effective pain management in patients with myofascial pain. However, the biochemical effects of remote dry needling are not well understood. This study evaluates the remote effects of dry needling with different dosages on the expressions of substance P (SP) in the proximal muscle, spinal dorsal horns of rabbits. Methods. Male New Zealand rabbits (2.5–3.0 kg) received dry needling at myofascial trigger spots of a gastrocnemius (distant muscle) in one (1D) or five sessions (5D). Bilateral biceps femoris (proximal muscles) and superficial laminaes of L5-S2, T2-T5, and C2-C5 were sampled immediately and 5 days after dry needling to determine the levels of SP using immunohistochemistry and western blot. Results. Immediately after dry needling for 1D and 5D, the expressions of SP were significantly decreased in ipsilateral biceps femoris and bilateral spinal superficial laminaes (P < .05). Five days after dry needling, these reduced immunoactivities of SP were found only in animals receiving 5D dry needling (P < .05). Conclusions. This remote effect of dry needling involves the reduction of SP levels in proximal muscle and spinal superficial laminaes, which may be closely associated with the control of myofascial pain. PMID:25276839

  18. Acute Effects of Different Methods of Stretching and Specific Warm-ups on Muscle Architecture and Strength Performance.

    PubMed

    Sá, Marcos A; Matta, Thiago T; Carneiro, Simone P; Araujo, Carolina O; Novaes, Jefferson S; Oliveira, Liliam F

    2016-08-01

    Sá, MA, Matta, TT, Carneiro, SP, Araujo, CO, Novaes, JS, and Oliveira, LF. Acute effects of different methods of stretching and specific warm-ups on muscle architecture and strength performance. J Strength Cond Res 30(8): 2324-2329, 2016-The purpose of the study was to investigate the acute effects of 2 stretching interventions, proprioceptive neuromuscular facilitation (PNF) and passive static stretching (PSS), and a specific warm-up (SW) on the strength and architecture of the vastus laterallis and biceps femoris muscles in a subsequent performance on a strength training session (STS). Musculoskeletal ultrasound images were acquired from 9 men before and immediately after stretchings or a SW, and 10 minutes after a STS. The STS consisted of the following exercises: leg extension, leg curl, leg press, and hack machine squat. The PNF resulted in lower performance for all situations. The PSS and SW improved performance for the leg press compared with the PNF and controls (CSs). For the hack machine squat, SWs resulted in higher performance than stretching conditions. The vastus lateralis muscle fascicle length (FL) increases after a STS for PNF. The biceps femoris muscle showed a higher pennation angle 10 minutes after the STS for PSS; the FL increases immediately after PSS and then decreases 10 minutes after the STS for PSS. As per our results, the SWs should be performed before STSs, whereas PNF stretching should not be prescribed because this condition impairs subsequent performance. These results may assist health professionals in prescribing resistance training.

  19. Acute Effects of Different Methods of Stretching and Specific Warm-ups on Muscle Architecture and Strength Performance.

    PubMed

    Sá, Marcos A; Matta, Thiago T; Carneiro, Simone P; Araujo, Carolina O; Novaes, Jefferson S; Oliveira, Liliam F

    2016-08-01

    Sá, MA, Matta, TT, Carneiro, SP, Araujo, CO, Novaes, JS, and Oliveira, LF. Acute effects of different methods of stretching and specific warm-ups on muscle architecture and strength performance. J Strength Cond Res 30(8): 2324-2329, 2016-The purpose of the study was to investigate the acute effects of 2 stretching interventions, proprioceptive neuromuscular facilitation (PNF) and passive static stretching (PSS), and a specific warm-up (SW) on the strength and architecture of the vastus laterallis and biceps femoris muscles in a subsequent performance on a strength training session (STS). Musculoskeletal ultrasound images were acquired from 9 men before and immediately after stretchings or a SW, and 10 minutes after a STS. The STS consisted of the following exercises: leg extension, leg curl, leg press, and hack machine squat. The PNF resulted in lower performance for all situations. The PSS and SW improved performance for the leg press compared with the PNF and controls (CSs). For the hack machine squat, SWs resulted in higher performance than stretching conditions. The vastus lateralis muscle fascicle length (FL) increases after a STS for PNF. The biceps femoris muscle showed a higher pennation angle 10 minutes after the STS for PSS; the FL increases immediately after PSS and then decreases 10 minutes after the STS for PSS. As per our results, the SWs should be performed before STSs, whereas PNF stretching should not be prescribed because this condition impairs subsequent performance. These results may assist health professionals in prescribing resistance training. PMID:26705067

  20. Muscle force output and electromyographic activity in squats with various unstable surfaces.

    PubMed

    Saeterbakken, Atle H; Fimland, Marius S

    2013-01-01

    The purpose of the study was to compare force output and muscle activity of leg and trunk muscles in isometric squats executed on stable surface (i.e., floor), power board, BOSU ball, and balance cone. Fifteen healthy men (23.3 ± 2.7 years, mass: 80.5 ± 8.5 kg, height: 1.81 ± 0.09 m) volunteered. The force output and electromyographic (EMG) activities of the rectus femoris, vastus medialis, vastus lateralis, biceps femoris, soleus, rectus abdominis, oblique external, and erector spinae were assessed. The order of the surfaces was randomized. One familiarization session was executed before the experimental test. Compared with stable surface (749 ± 222 N), the force output using power board was similar (-7%, p = 0.320) but lower for BOSU ball (-19%, p = 0.003) and balance cone (-24%, p ≤ 0.001). The force output using BOSU ball and balance cone was approximately 13% (p = 0.037) and approximately 18% (p = 0.001) less than the power board. There were similar EMG activities between the surfaces in all muscles except for rectus femoris, in which stable squat provided greater EMG activity than did the other exercises (p = 0.004-0.030). Lower EMG activity was observed in the rectus femoris using balance cone compared with the BOSU ball (p = 0.030). In conclusion, increasing the instability of the surface during maximum effort isometric squats usually maintains the muscle activity of lower-limb and superficial trunk muscles although the force output is reduced. This suggests that unstable surfaces in the squat may be beneficial in rehabilitation and as a part of periodized training programs, because similar muscle activity can be achieved with reduced loads.

  1. Size of quadriceps femoris may contribute to thyrotoxic periodic paralysis.

    PubMed

    Tang, Zi-Wei; He, Ying; Yao, Yu; Qiu, Li; Tian, Hao-Ming

    2015-12-01

    Thyrotoxic periodic paralysis (TPP) frequently occurs on male individuals at their third and forth decades. The major site of involvement is the proximal muscles of lower limbs. Increasing evidence has shown that the occurrence of TPP is determined by multiple factors. We hypothesized that apart from hormonal fluctuations, skeletal muscle itself may explain for the age and sex variance as well. Our study was established to explore whether the size of lower limb skeletal muscles were related to TPP. We conducted a clinical experiment including 43 patients diagnosed with TPP (Group 1) and 39 pure hyperthyroidism individuals (Group 2). Current age, body mass index (BMI), thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), average girth of bilateral upper arm and thigh, physical activity level (PAL) were measured. We also adopted B mode ultrasound to quantify the muscle thickness (MT) of the major muscle involved in the disease, the quadriceps femoris (QF, including rectus femoris, RF; vastus intermedius, VI; vastus medialis, VM and vastus lateralis, VL). Patients were matched in TSH, FT4 and FT3. PAL was also statistically identical between groups. Age, BMI, thigh girth, the average of bilateral MT of QF were statistically different. After adjusting for age, BMI and girth, Group 1 still presented with larger MT of QF than Group 2, regardless of their current thyroid hormone level. There indeed exists an independent relationship between muscle thickness and TPP. PMID:26519100

  2. Electromyographic responses of erector spinae and lower limb's muscles to dynamic postural perturbations in patients with adolescent idiopathic scoliosis.

    PubMed

    Farahpour, Nader; Ghasemi, Safoura; Allard, Paul; Saba, Mohammad Sadegh

    2014-10-01

    The aim of this study was to evaluate electromyographic (EMG) responses of erector spinae (ES) and lower limbs' muscles to dynamic forward postural perturbation (FPP) and backward postural perturbation (BPP) in patients with adolescent idiopathic scoliosis (AIS) and in a healthy control group. Ten right thoracic AIS patients (Cobb=21.6±4.4°) and 10 control adolescents were studied. Using bipolar surface electrodes, EMG activities of ES muscle at T10 (EST10) and L3 (ESL3) levels, biceps femoris (BF), gastrocnemius lateralis (G) and rectus femoris (RF) muscles in the right and the left sides during FPP and BPP were evaluated. Muscle responses were measured over a 1s time window after the onset of perturbation. In FPP test, the EMG responses of right EST10, ESL3 and BF muscles in the scoliosis group were respectively about 1.40 (p=0.035), 1.43 (p=0.07) and 1.45 (p=0.01) times greater than those in control group. Also, in BPP test, at right ESL3 muscle of the scoliosis group the EMG activity was 1.64 times higher than that in the control group (p=0.01). The scoliosis group during FPP displayed asymmetrical muscle responses in EST10 and BF muscles. This asymmetrical muscle activity in response to FPP is hypothesized to be a possible compensatory strategy rather than an inherent characteristic of scoliosis.

  3. Clinical and Muscle Imaging Findings in 14 Mainland Chinese Patients with Oculopharyngodistal Myopathy

    PubMed Central

    Zhao, Juan; Liu, Jing; Xiao, Jiangxi; Du, Jing; Que, Chengli; Shi, Xin; Liang, Wei; Sun, Weiping; Zhang, Wei; Lv, He; Yuan, Yun; Wang, Zhaoxia

    2015-01-01

    Oculopharyngodistal myopathy (OPDM) is an extremely rare, adult-onset hereditary muscular disease characterized by progressive external ocular, pharyngeal, and distal muscle weakness and myopathological rimmed vacuole changes. The causative gene is currently unknown; therefore, diagnosis of OPDM is based on clinical and histopathological features and genetic exclusion of similar conditions. Moreover, variable manifestations of this disorder are reported in terms of muscle involvement and severity. We present the clinical profile and magnetic resonance imaging (MRI) changes of lower limb muscles in 14 mainland Chinese patients with OPDM, emphasizing the role of muscle MRI in disease identification and differential diagnosis. The patients came from 10 unrelated families and presented with progressive external ocular, laryngopharyngeal, facial, distal limb muscle weakness that had been present since early adulthood. Serum creatine kinase was mildly to moderately elevated. Electromyography revealed myogenic changes with inconsistent myotonic discharge. The respiratory function test revealed subclinical respiratory muscle involvement. Myopathological findings showed rimmed vacuoles with varying degrees of muscular dystrophic changes. All known genes responsible for distal and myofibrillar myopathies, vacuolar myopathies, and muscular dystrophies were excluded by PCR or targeted next-generation sequencing. Muscle MRI revealed that the distal lower legs had more severe fatty replacement than the thigh muscles. Serious involvement of the soleus and long head of the biceps femoris was observed in all patients, whereas the popliteus, gracilis and short head of biceps femoris were almost completely spared, even in advanced stages. Not only does our study widen the spectrum of OPDM in China, but it also demonstrates that OPDM has a specific pattern of muscle involvement that may provide valuable information for its differential diagnosis and show further evidence supporting

  4. Biceps tendinitis caused by an osteochondroma in the bicipital groove: a rare cause of shoulder pain in a baseball player.

    PubMed

    Onga, Takafumi; Yamamoto, Tetsuji; Akisue, Toshihiro; Marui, Takashi; Kurosaka, Masahiro

    2005-02-01

    Tendinitis of the long head of the biceps brachii muscle is commonly seen in athletes who do repetitive overhead motions. Common causes of biceps tendinitis include impingement syndrome, subluxation of the biceps tendon, and attrition tendinitis, whereas biceps tendinitis secondary to a bone neoplasm is rare. A case of biceps tendinitis caused by an osteochondroma arising in the left humeral bicipital groove in a 25-year-old male baseball player is reported. The tumor was hook-shaped, originated from the inferomedial portion of the humeral lesser tubercle, and surrounded the biceps tendon. Symptoms of increasing pain and inability to throw resulted from direct irritation of the biceps tendon by the tumor. Total excision of the tumor relieved the symptoms within 3 weeks. To our knowledge, there have been no reported cases in the English-language literature of biceps tendinitis caused by an osteochondroma.

  5. Muscle activation during lower body resistance training.

    PubMed

    Ebben, W P; Feldmann, C R; Dayne, A; Mitsche, D; Alexander, P; Knetzger, K J

    2009-01-01

    This study evaluated the biceps femoris (BF), rectus femoris (RF), and vastus lateralis (VL) activation and activation ratios of a variety of resistance training exercises characterized by knee extension, and determined if subject strength or gender affects these variables. The exercises evaluated included the leg extension, squat, deadlift, lunge, and step up. Subjects included 20 athletes and recreationally active college students. Electromyography (EMG) of the muscles expressed as a percentage of maximum voluntary isometric contraction (MVIC), as well as the BF to RF and BF to VL EMG ratio, were determined for each exercise. There was no significant interaction between gender and exercise type for the RMS EMG of the BF (p = 0.67), RF (p = 0.53), or VL (p = 0.06). Main effects were found for the RMS EMG of the BF (p = 0.00), RF (p = 0.00), and VL (p = 0.00), as well as the RMS EMG of the BF to RF activation ratio (p = 0.00) and BF to VL activation ratios (p = 0.003), between exercises. Peak RMS EMG was also assessed. Post hoc analysis identified specific differences in muscle activation and ratios between exercises. Clinicians should consider the magnitude of muscle activation and activation ratios when prescribing hamstring and quadriceps exercises. PMID:18975260

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

    PubMed

    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.

  7. 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

  8. Nonuniform changes in MRI measurements of the thigh muscles after two hamstring strengthening exercises.

    PubMed

    Mendiguchia, Jurdan; Garrues, Mirian A; Cronin, John B; Contreras, Bret; Los Arcos, Asier; Malliaropoulos, Nikos; Maffulli, Nicola; Idoate, Fernando

    2013-03-01

    Although many different hamstring strengthening exercises exist, the effect on site specific activation of these exercises on different muscles of the leg is unclear. This study investigated the effects of the eccentric leg curl (LC) and lunge (L) exercises on the biceps femoris long head (BFl), biceps femoris short head (BFs), semitendinosus (ST), semimembranosus (SM), and adductor magnus (AM). Each leg of 11 male professional soccer players was randomly assigned to an LC or L exercise protocol (3 sets of 6 repetitions). Functional magnetic resonance imaging (fMRI) of the subjects' thighs were performed before and 48 hours after the intervention. Fifteen axial scans of the thigh interspaced by a distance of 1/15 right femur length (Lf) were obtained. The fMRI data were analyzed for signal intensity changes. No significant changes were observed in absolute short tau inversion recovery values for the SM and BFs. Significant changes for the ST (∼21-45%) from sections 4 to 10, AM (∼2-13%) at section 4, and BFl (∼ -3 vs. 8%) at section 7 were noted. LC exercises load all the regions of the ST muscle. The L exercises load the proximal regions of the BFl and AM. These findings may have relevance when designing protocols for prevention and rehabilitation of hamstring injuries. PMID:23443215

  9. [Comparative studies on looking into lacertus fibrosis and aponeurosis of the bicipitis brachii muscle as well as assessment of the biceps brachii and bracialis muscles in sheep, goats and wild deer].

    PubMed

    Künzel, W; Forstenpointner, G

    1994-12-01

    In 34 anatomical specimens of sheep, goat and fallow deer the development of the cranial brachial and antebrachial fascia as well as the occurrence of a lacertus fibrosus and of structures, that are homologous with the aponeurosis m. bicipitis brachii hominis, were studied. Additionally, the attachments of the m. biceps brachii and the m. brachialis were dissected. In sheep, goat and fallow deer the superficial layer of the fascia brachii et antebrachii is weakly developed. Its deeper stratum, originating in the tuberositas deltoidea as well as in the crista humeri, and on the forearm interspersing with the fascia of the m. extensor carpi radialis, is of a more robust composition. In goat and fallow deer a remarkable ligamentous bracing of this fascial layer stresses its cranial aspect. The lacertus fibrosus intermingles in all three species with the cranial fascia antebrachii respectively with the tendon of the m. extensor carpi radialis. While in sheep and goat its emergence from the m. biceps brachii is obviously bipartite, in fallow deer this part of the lacertus fibrosus is undivided. Moreover, in all three species a muscular and/or tendinous connection between the m. biceps brachii and the m. pronator teres exists, that is homologous with the aponeurosis m. bicipitis brachii hominis. In sheep, goat and fallow deer the m. biceps brachii attaches with each one tendon to the tuberositas radii and the processus coronoideus med. ulnae. Frequently in sheep, but rarely in goat the ulnar tendon extends its area of attachment to the radius.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7832287

  10. Effects of ACL reconstruction surgery on muscle activity of the lower limb during a jump-cut maneuver in males and females.

    PubMed

    Coats-Thomas, Margaret S; Miranda, Daniel L; Badger, Gary J; Fleming, Braden C

    2013-12-01

    We compared muscle activity of the quadriceps, hamstring, and gastrocnemius muscles when ACL-intact (ACL(INT)) and ACL-reconstructed (ACL(REC)) male and female subjects performed a jump-cut task. Surface electromyography sensors were used to evaluate time to peak muscle activity and muscle activity ratios. Rectus femoris (RF) and vastus medialis (VM) peak timing was 71 and 78 ms earlier in ACL(INT) than in ACL(REC) subjects, respectively. Biceps femoris (BF) peak timing was 90 ms earlier in ACL(INT) than in ACL(REC) subjects and 75 ms earlier in females than in males. Medial gastrocnemius (MG) muscle peak timing was 77 ms earlier in ACL(INT) than in ACL(REC) subjects. Lateral gastrocnemius (LG) and MG muscle peak times were 106 ms and 87 ms earlier in females than in males, respectively. The RF, VM, BF, and MG peaked later in ACL(REC) than in ACL(INT) subjects. There was evidence suggesting that the loading phase quadriceps:hamstring (quad:ham) muscle activity ratio was greater in ACL(REC) than in ACL(INT) subjects. Finally, the injury risk phase quad:ham muscle activity ratio was 4.8 times greater in females than in males. In conclusion, differences exist in muscle activity related to ACL status and sex that could potentially help explain graft failure risk and the sex bias.

  11. Aging affects spatial distribution of leg muscle oxygen saturation during ramp cycling exercise.

    PubMed

    Takagi, Shun; Kime, Ryotaro; Murase, Norio; Watanabe, Tsubasa; Osada, Takuya; Niwayama, Masatsugu; Katsumura, Toshihito

    2013-01-01

    We compared muscle oxygen saturation (SmO2) responses in several leg muscles and within a single muscle during ramp cycling exercise between elderly men (n = 8; age, 65 ± 3 years; ELD) and young men (n = 10; age, 23 ± 3 years; YNG). SmO2 was monitored at the distal site of the vastus lateralis (VLd), proximal site of the vastus lateralis (VLp), rectus femoris (RF), vastus medialis (VM), biceps femoris (BF), gastrocnemius lateralis (GL), gastrocnemius medialis (GM), and tibialis anterior (TA) by near-infrared spatial resolved spectroscopy. During submaximal exercise, significantly lower SmO2 at a given absolute work rate was observed in VLd, RF, BF, GL, and TA but not in VLp, VM, and GM in ELD than in YNG. In contrast, at all measurement sites, SmO2 at peak exercise was not significantly different between groups. These results indicate that the effects of aging on SmO2 responses are heterogeneous between leg muscles and also within a single muscle. The lower SmO2 in older men may have been caused by reduced muscle blood flow or altered blood flow distribution.

  12. Effect of the shoulder position on the biceps brachii emg in different dumbbell curls

    PubMed Central

    Oliveira, Liliam F.; Matta, Thiago T.; Alves, Daniel S.; Garcia, Marco A.C.; Vieira, Taian M.M.

    2009-01-01

    Incline Dumbbell Curl (IDC) and Dumbbell Preacher Curl (DPC) are two variations of the standard Dumbbell Biceps Curl (DBC), generally applied to optimize biceps brachii contribution for elbow flexion by fixing shoulder at a specific angle. The aim of this study is to identify changes in the neuromuscular activity of biceps brachii long head for IDC, DPC and DBC exercises, by taking into account the changes in load moment arm and muscle length elicited by each dumbbell curl protocol. A single cycle (concentric-eccentric) of DBC, IDC and DPC, was applied to 22 subjects using a submaximal load of 40% estimated from an isometric MVC test. The neuromuscular activity of biceps brachii long head was compared by further partitioning each contraction into three phases, according to individual elbow joint range of motion. Although all protocols elicited a considerable level of activation of the biceps brachii muscle (at least 50% of maximum RMS), the contribution of this muscle for elbow flexion/extension varied among exercises. The submaximal elbow flexion (concentric) elicited neuro muscular activity up to 95% of the maximum RMS value during the final phase of IDC and DBC and 80% for DPC at the beginning of the movement. All exercises showed significant less muscle activity for the elbow extension (eccentric). The Incline Dumbbell Curl and the classical Dumbbell Biceps Curl resulted in similar patterns of biceps brachii activation for the whole range of motion, whereas Dumbbell Preacher Curl elicited high muscle activation only for a short range of elbow joint angle. Key pointsThe Incline Dumbbell Curl and the Dumbbell Biceps Curl resulted in a considerable neuromuscular effort throughout the whole elbow range of motion.The Incline Dumbbell Curl and the Dumbbell Biceps Curl may be preferable for the improvement of biceps brachii force in training programs. PMID:24150552

  13. Muscle Activation and Onset Times of Hip Extensors during Various Loads of a Closed Kinetic Chain Exercise.

    PubMed

    Cochrane, Darryl J; Barnes, Matthew J

    2015-01-01

    The aim of this study was to determine the muscle activity and onset time of hip extensors during a closed kinetic chain exercise (deadlift) at sub-maximal loads of 30%, 40%, 50%, and 75% of one repetition maximum (1RM). Twelve healthy males with at least three years of resistance training experience volunteered for the study. Biceps femoris (BF) and gluteus maximus (GM) muscle activity, onset time, peak and mean power were measured during the concentric phase of the deadlift. There was no main effect (p > 0.05) or no interaction effect for the onset time in BF and GM and for each load BF and GM had similar muscle activity. Increasing the external load during deadlift had no adverse effect on the relative onset time and it did not promote BF onset to occur before GM onset, thus both muscles were simultaneously activated, which should not compromise a delay in GM. PMID:25656945

  14. 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

  15. Comparative anatomy and muscle architecture of selected hind limb muscles in the Quarter Horse and Arab.

    PubMed

    Crook, T C; Cruickshank, S E; McGowan, C M; Stubbs, N; Wakeling, J M; Wilson, A M; Payne, R C

    2008-02-01

    The Quarter Horse (bred for acceleration) and the Arab (bred for endurance) are situated at either end of the equine athletic spectrum. Studies into the form and function of the leg muscles in human sprint and endurance runners have demonstrated that differences exist in their muscle architecture. It is not known whether similar differences exist in the horse. Six Quarter Horse and six Arab fresh hind limb cadavers were dissected to gain information on the muscle mass and architecture of the following muscles: gluteus medius; biceps femoris; semitendinosus; vastus lateralis; gastrocnemius; tibialis cranialis and extensor digitorum longus. Specifically, muscle mass, fascicle length and pennation angle were quantified and physiological cross-sectional area (PCSA) and maximum isometric force were estimated. The hind limb muscles of the Quarter Horse were of a significantly greater mass, but had similar fascicle lengths and pennation angles when compared with those of the Arab; this resulted in the Quarter Horse hind limb muscles having greater PCSAs and hence greater isometric force potential. This study suggests that Quarter Horses as a breed inherently possess large strong hind limb muscles, with the potential to accelerate their body mass more rapidly than those of the Arab.

  16. Signal intensity of MR-images of thigh muscles following acute open- and closed chain kinetic knee extensor exercise - index of muscle use.

    PubMed

    Enocson, A G; Berg, H E; Vargas, R; Jenner, G; Tesch, P A

    2005-07-01

    Exercise-induced shifts in signal intensity (SI) of magnetic resonance (MR) images were examined to assess indirectly muscle use in closed- and open-chain knee extensor exercises. Eight men performed five sets of 8-12 repetitions in the leg press (LP) and the seated knee extension (KE) exercises at 50, 75 and 100%, respectively of the 5 x 10 repetition maximum (RM) load. Prior to exercise and after each load setting, images of the thigh were obtained. The increase in SI (Delta SI) of the quadriceps at 100% load was greater (P < 0.05) after KE (32.1 +/- 9.0%) than after LP (21.9 +/- 9.2%). Regardless of load, the four individual muscles of the quadriceps showed similar changes in SI after LP. The three vastii muscles showed comparable increases in SI after KE. M. rectus femoris showed greater (P < 0.05) Delta SI than the vastii muscles at 100%. Neither exercise produced increase in SI of mm. semimembranosus, semitendinosus, gracilis or biceps femoris. Mm. adductor magnus and longus showed increased (13.3 +/- 6.5%; P < 0.05) SI after LP, but not after KE, at 100% load. The present data also infer greater involvement of the quadriceps muscle in the open-chain knee extension than in the closed-chain leg press exercise. The results of the current investigation also indicate similar over-all use among the three vastii muscles in LP and KE, but differential m. rectus femoris use between the two exercises. This report extends the merits of the MR imaging technique as an aid to study individual muscle involvement in a particular exercise task. PMID:15918061

  17. Effect of the beta-adrenergic agonist L644,969 on muscle growth, endogenous proteinase activities, and postmortem proteolysis in wether lambs.

    PubMed

    Koohmaraie, M; Shackelford, S D; Muggli-Cockett, N E; Stone, R T

    1991-12-01

    To examine the effect of a beta-adrenergic agonist (BAA) on muscle growth, proteinase activities, and postmortem proteolysis, 16 wether lambs were randomly assigned to receive 0 or 4 ppm of L644,969 in a completely mixed high-concentrate diet for 6 wk. Weight of the biceps femoris was 18.6% heavier in treated lambs. At 0 h after slaughter, treated lambs had higher cathepsin B (35.6%), cathepsins B + L (19.1%), calpastatin (62.8%), and m-calpain (24.6%) than control lambs, but both groups had similar mu-calpain activities. In both longissimus and biceps femoris muscles, treated lambs had higher protein and RNA and lower DNA concentrations. However, total DNA was not affected, indicating that the increase in muscle mass was probably due to muscle hypertrophy rather than to hyperplasia. The pattern of postmortem proteolysis was significantly altered by BAA feeding. In treated lambs, postmortem storage had no effect on the myofibril fragmentation index and degradation of desmin and troponin-T. These results indicate that the ability of the muscle to undergo postmortem proteolysis has been dramatically reduced with BAA feeding. Similar proteolytic systems are thought to be involved in antemortem and postmortem degradation of myofibrillar proteins, so BAA-mediated protein accretion is probably due, at least in part, to reduced protein degradation. To examine whether protein synthesis was altered with BAA feeding, the level of skeletal muscle alpha-actin mRNA was quantified. Longissimus muscle alpha-actin mRNA abundance was 30% greater in BAA-fed lambs. Collectively, these results indicate that dietary administration of BAA increases muscle mass through hypertrophy and that the increase in muscle protein accretion is due to reduced degradation and possibly to increased synthesis of muscle proteins.

  18. Muscle contributions to propulsion and braking during walking and running: insight from external force perturbations.

    PubMed

    Ellis, Richard G; Sumner, Bonnie J; Kram, Rodger

    2014-09-01

    There remains substantial debate as to the specific contributions of individual muscles to center of mass accelerations during walking and running. To gain insight, we altered the demand for muscular propulsion and braking by applying external horizontal impeding and aiding forces near the center of mass as subjects walked and ran on a treadmill. We recorded electromyographic activity of the gluteus maximus (superior and inferior portions), the gluteus medius, biceps femoris, semitendinosus/membrinosus, vastus medialis, lateral and medial gastrocnemius and soleus. We reasoned that activity in a propulsive muscle would increase with external impeding force and decrease with external aiding force whereas activity in a braking muscle would show the opposite. We found that during walking the gastrocnemius and gluteus maximus provide propulsion while the vasti are central in providing braking. During running, we found that the gluteus maximus, vastus medialis, gastrocnemius and soleus all contribute to propulsion.

  19. Comparison of toe grip strength and muscle activities during maximal toe grip strength exertion according to the presence/absence of an ankle immobilization belt.

    PubMed

    Soma, Masayuki; Murata, Shin; Kai, Yoshihiro; Nakae, Hideyuki; Satou, Yousuke; Murata, Jun; Miyazaki, Junya

    2015-10-01

    [Purpose] The aim of this study was to compare toe grip strength and muscle activity during toe grip strength exertion according to the presence/absence of an ankle immobilization belt and to examine the relationship between the differences in muscle activity and toe grip strength. [Subjects] The Subjects were 13 healthy young women. [Methods] We measured toe grip strength and muscle activity during toe grip strength exertion in the presence and absence of an ankle immobilization belt using electromyography. Activity in the following leg muscles was recorded: rectus femoris, biceps femoris, medial head of the gastrocnemius, and tibialis anterior. We then calculated the percent integrated electromyography during toe gripping. [Results] Toe grip strength and percent integrated electromyography of the medial head of the gastrocnemius muscle were significantly higher with ankle belt immobilization compared with without ankle belt immobilization. In addition, in the presence of ankle belt immobilization, the percent integrated electromyography of the tibialis anterior muscle and medial head of the gastrocnemius muscle demonstrated a positive correlation with toe grip strength (r = 0.75 and r = 0.65, respectively). [Conclusion] These findings suggest that greater toe grip strength could be exerted in the presence of ankle belt immobilization. The measured values reflect the percent integrated electromyography of the crural muscles. Therefore, it was shown that toe grip strength should be measured in the presence of an immobilization belt.

  20. Muscle-specific glucose and free fatty acid uptake after sprint interval and moderate-intensity training in healthy middle-aged men.

    PubMed

    Eskelinen, Jari-Joonas; Heinonen, Ilkka; Löyttyniemi, Eliisa; Saunavaara, Virva; Kirjavainen, Anna; Virtanen, Kirsi A; Hannukainen, Jarna C; Kalliokoski, Kari K

    2015-05-01

    We tested the hypothesis that sprint interval training (SIT) causes larger improvements in glucose and free fatty acid uptake (FFAU) in lower and upper body muscles than moderate-intensity training (MIT). Twenty-eight healthy, untrained, middle-aged men were randomized into SIT (n = 14, 4-6 × 30 s of all-out cycling/4 min recovery) and MIT groups [n = 14, 40-60 min cycling at 60% of peak O2 uptake (V̇o2 peak)] and completed six training sessions within 2 wk. Pre- and postmeasurements included V̇o2 peak, whole body (M-value), muscle-specific insulin-stimulated glucose uptake (GU), and fasting FFAU measured with positron emission tomography in thigh [quadriceps femoris (QF) and hamstrings] and upper body (deltoids, biceps, and triceps brachii) muscles. V̇o2 peak and M-value improved significantly by 6 and 12% in SIT, and 3 and 8% in MIT, respectively,. GU increased significantly only in the QF, and there was no statistically significant difference between the training modes. GU increased in all four heads of QF in response to SIT, but only in the vasti muscles in response to MIT, whereas in rectus femoris the response was completely lacking. Training response in FFAU in QF was smaller and nonsignificant, but it also differed between the training modes in the rectus femoris. In conclusion, SIT and MIT increased insulin-stimulated GU only in the main working muscle QF and not in the upper body muscles. In addition, the biarticular rectus femoris did not respond to moderate-intensity training, reflecting most probably poor activation of it during moderate-intensity cycling. PMID:25767035

  1. Computational Models Predict Larger Muscle Tissue Strains at Faster Sprinting Speeds

    PubMed Central

    Fiorentino, Niccolo M; Rehorn, Michael R; Chumanov, Elizabeth S; Thelen, Darryl G; Blemker, Silvia S

    2014-01-01

    Introduction: Proximal biceps femoris musculotendon strain injury has been well established as a common injury among athletes participating in sports that require sprinting near or at maximum speed; however, little is known about the mechanisms that make this muscle tissue more susceptible to injury at faster speeds. Purpose: Quantify localized tissue strain during sprinting at a range of speeds. Methods: Biceps femoris long head (BFlh) musculotendon dimensions of 14 athletes were measured on magnetic resonance (MR) images and used to generate a finite element computational model. The model was first validated through comparison with previous dynamic MR experiments. After validation, muscle activation and muscle-tendon unit length change were derived from forward dynamic simulations of sprinting at 70%, 85% and 100% maximum speed and used as input to the computational model simulations. Simulations ran from mid-swing to foot contact. Results: The model predictions of local muscle tissue strain magnitude compared favorably with in vivo tissue strain measurements determined from dynamic MR experiments of the BFlh. For simulations of sprinting, local fiber strain was non-uniform at all speeds, with the highest muscle tissue strain where injury is often observed (proximal myotendinous junction). At faster sprinting speeds, increases were observed in fiber strain non-uniformity and peak local fiber strain (0.56, 0.67 and 0.72, for sprinting at 70%, 85% and 100% maximum speed). A histogram of local fiber strains showed that more of the BFlh reached larger local fiber strains at faster speeds. Conclusions: At faster sprinting speeds, peak local fiber strain, fiber strain non-uniformity and the amount of muscle undergoing larger strains are predicted to increase, likely contributing to the BFlh muscle’s higher injury susceptibility at faster speeds. PMID:24145724

  2. Determination of muscle activity during running at reduced body weight.

    PubMed

    Liebenberg, Jaco; Scharf, Jennifer; Forrest, Dana; Dufek, Janet S; Masumoto, K; Mercer, J A

    2011-01-01

    The aim of this study was to investigate how lower extremity muscles are influenced by body weight support during running at different speeds. Nine participants (age 24 ± 2 years, height 1.75 ± 0.12 m, mass 73.5 ± 15.7 kg) ran at 100%, 115%, and 125% of preferred speed at 100%, 90%, 80%, 70%, and 60% of body weight on a treadmill that provided body weight support. Preferred speed was self-selected by each participant and represented a speed that he or she could sustain if going for a 30 min run. Electromyography (EMG) data were recorded (1000 Hz, 1 min) from the bicep femoris, rectus femoris, tibialis anterior, and gastrocnemius for each condition together with knee angle (electrogoniometer). Average and root mean square EMG were calculated across 30 s. Muscle patterns were determined by smoothing (low-pass filter, 4 Hz) and extracting patterns for 49 cycles defined by consecutive maximum knee flexion angles. Repeated-measures analyses of variance were used to compare average and root mean square across body weight and speeds. Correlations were computed between the 100% speed/100% body weight condition and all other conditions per muscle. There was no interaction between body weight and speed (P > 0.05). Average and root mean square decreased as body weight decreased for all muscles (P < 0.05) and increased across speeds for all muscles (P < 0.05). Correlations for all muscles between conditions were high (range: 0.921-0.999). Although a percent reduction in body weight did not lead to the same reduction in muscle activity, it was clear that reducing body weight leads to a reduction in muscle activity with no changes in muscle activity patterns. PMID:21170806

  3. Joint torque and angle estimation by using ultrasonic muscle activity sensor

    NASA Astrophysics Data System (ADS)

    Tsutsui, Yoichiro; Tanaka, Takayuki; Kaneko, Shun'ichi; Feng, Maria Q.

    2005-12-01

    We have proposed a brand-new noninvasive ultrasonic sensor for measuring muscle activities named as Ultrasonic Muscle Activity Sensor (UMS). In the previous paper, the authors achieved to accurately estimate joint torque by using UMS and electromyogram (EMG) which is one of the most popular sensors. This paper aims to realize to measure not only joint torque also joint angle by using UMS and EMG. In order to estimate torque and angle of a knee joint, muscle activities of quadriceps femoris and biceps femoris were measured by both UMS and EMG. These targeted muscles are related to contraction and extension of knee joint. Simultaneously, actual torque on the knee joint caused by these muscles was measured by using torque sensor. The knee joint angle was fixed by torque sensor in the experiment, therefore the measurement was in isometric state. In the result, we found that the estimated torque and angle have high correlation coefficient to actual torque and angle. This means that the sensor can be used for angle estimation as well torque estimation. Therefore, it is shown that the combined use of UMS and EMG is effective to torque and angle estimation.

  4. Recovery of gait after quadriceps muscle fatigue.

    PubMed

    Barbieri, Fabio Augusto; Beretta, Stephannie Spiandor; Pereira, Vinicius A I; Simieli, Lucas; Orcioli-Silva, Diego; dos Santos, Paulo Cezar Rocha; van Dieën, Jaap H; Gobbi, Lilian Teresa Bucken

    2016-01-01

    The aim of this study was to investigate the effect of recovery time after quadriceps muscle fatigue on gait in young adults. Forty young adults (20-40 years old) performed three 8-m gait trials at preferred velocity before and after muscle fatigue, and after 5, 10 and 20min of passive rest. In addition, at each time point, two maximal isometric voluntary contractions were preformed. Muscle fatigue was induced by repeated sit-to-stand transfers until task failure. Spatio-temporal, kinetic and muscle activity parameters, measured in the central stride of each trial, were analyzed. Data were compared between before and after the muscle fatigue protocol and after the recovery periods by one-way repeated measures ANOVA. The voluntary force was decreased after the fatigue protocol (p<0.001) and after 5, 10 and 20min of recovery compared to before the fatigue protocol. Step width (p<0.001) and RMS of biceps femoris (p<0.05) were increased immediately after the fatigue protocol and remained increased after the recovery periods. In addition, stride duration was decreased immediately after the fatigue protocol compared to before and to after 10 and 20min of rest (p<0.001). The anterior-posterior propulsive impulse was also decreased after the fatigue protocol (p<0.001) and remained low after 5, 10 and 20min of rest. We conclude that 20min is not enough to see full recovery of gait after exhaustive quadriceps muscle fatigue.

  5. Effects of individual strengthening exercises for the stabilization muscles on the nutation torque of the sacroiliac joint in a sedentary worker with nonspecific sacroiliac joint pain

    PubMed Central

    Yoo, Won-gyu

    2015-01-01

    [Purpose] We investigated the effects of individual strengthening exercises for the stabilization muscles on the nutation torque of the sacroiliac joint in a sedentary worker with nonspecific sacroiliac joint pain. [Subject] A 36-year-old female complained of pain in the sacroiliac joints. [Methods] The subject performed individual strengthening exercises for the stabilization muscles for nutation torque of the sacroiliac joint for 3 weeks. Pain-provocation tests and visual analog scale (VAS) scores were evaluated before and after the exercises. [Results] After performing the individual strengthening exercises for the erector spinae, rectus abdominis, and biceps femoris muscles for 3 weeks, the subject displayed no pain in the pain provocation tests, and the VAS score was 2/10. [Conclusion] The individual strengthening exercises for the stabilization muscles of the sacroiliac joint performed in the present study appear to be effective for sedentary workers with sacroiliac joint pain. PMID:25642098

  6. Do sarcomere length, collagen content, pH, intramuscular fat and desmin degradation explain variation in the tenderness of three ovine muscles?

    PubMed

    Starkey, Colin P; Geesink, Geert H; Collins, Damian; Hutton Oddy, V; Hopkins, David L

    2016-03-01

    The longissimus (n=118) (LL), semimembranosus (n=104) (SM) and biceps femoris (n=134) (BF) muscles were collected from lamb and sheep carcases and aged for 5days (LL and SM) and 14days (BF) to study the impact of muscle characteristics on tenderness as assessed by shear force (SF) and sensory evaluation. The impact of gender, animal age, collagen content, sarcomere length (SL), desmin degradation, ultimate pH and intramuscular fat (IMF) on tenderness was examined. The main factors which influenced SF of the LL were IMF, SL and desmin degradation, but for sensory tenderness, IMF, ultimate pH and gender were the main factors. The SF and sensory tenderness of the SM was best predicted by the degree of desmin degradation. For the BF soluble collagen and animal age both influenced SF. Different factors affect tenderness across muscles and not one prediction model applied across all muscles equally well.

  7. Acute changes in kinematic and muscle activity patterns in habitually shod rearfoot strikers while running barefoot.

    PubMed

    Strauts, Janina; Vanicek, Natalie; Halaki, Mark

    2016-01-01

    The aim of this study was to observe changes in the kinematics and muscle activities when barefoot running was initially adopted by six habitually shod, recreational rearfoot striking runners. Participants ran on a treadmill shod for 5 min, completed 3 × 10-min intervals of barefoot running and then completed a final minute of shod running at a self-selected pace. Dependent variables (speed, joint angles at foot-contact, joint range of motion (ROM), mean and peak electromyography (EMG) activity) were compared across conditions using repeated measures ANOVAs. Anterior pelvic tilt and hip flexion significantly decreased during barefoot conditions at foot contact. The ROM for the trunk, pelvis, knee and ankle angles decreased during the barefoot conditions. Mean EMG activity was reduced for biceps femoris, gastrocnemius lateralis and tibialis anterior during barefoot running. The peak activity across the running cycle decreased in biceps femoris, vastus medialis, gastrocnemius medialis and tibialis anterior during barefoot running. During barefoot running, tibialis anterior activity significantly decreased during the pre-activation and initial contact phases; gastrocnemius lateralis and medialis activity significantly decreased during the push-off phase. Barefoot running caused immediate biomechanical and neuromuscular adaptations at the hip and pelvis, which persisted when the runners donned their shoes, indicating that some learning had occurred during an initial short bout of barefoot running.

  8. Peak Muscle Activation, Joint Kinematics, and Kinetics during Elliptical and Stepping Movement Pattern on a Precor Adaptive Motion Trainer

    ERIC Educational Resources Information Center

    Rogatzki, Matthew J.; Kernozek, Thomas W.; Willson, John D.; Greany, John F.; Hong, Di-An; Porcari, John P.

    2012-01-01

    Kinematic, kinetic, and electromyography data were collected from the biceps femoris, rectus femoris (RF), gluteus maximus, and erector spinae (ES) during a step and elliptical exercise at a standardized workload with no hand use. Findings depicted 95% greater ankle plantar flexion (p = 0.01), 29% more knee extension (p = 0.003), 101% higher peak…

  9. Assessment of Muscle Contractile Properties at Acute Moderate Altitude Through Tensiomyography.

    PubMed

    Morales-Artacho, Antonio J; Padial, Paulino; Rodríguez-Matoso, Dario; Rodríguez-Ruiz, David; García-Ramos, Amador; García-Manso, Juan Manuel; Calderón, Carmen; Feriche, Belén

    2015-12-01

    Under hypoxia, alterations in muscle contractile properties and faster fatigue development have been reported. This study investigated the efficacy of tensiomyography (TMG) in assessing muscle contractile function at acute moderate altitude. Biceps femoris (BF) and vastus lateralis (VL) muscles of 18 athletes (age 20.1 ± 6.1 years; body mass 65.4 ± 13.9 kg; height 174.6 ± 9.5 cm) were assessed at sea level and moderate altitude using electrically evoked contractions on two consecutive days. Maximum radial displacement (Dm), time of contraction (Tc), reaction time (Td), sustained contraction time (Ts), and relaxation time (Tr) were recorded at 40, 60, 80, and 100 mA. At altitude, VL showed lower Dm values at 40 mA (p = 0.008; ES = -0.237). Biceps femoris showed Dm decrements in all electrical stimulations (p < 0.001, ES > 0.61). In VL, Tc was longer at altitude at 40 (p = 0.031, ES = 0.56), and 100 mA (p = 0.03, ES = 0.51). Regarding Td, VL showed significant increases in all electrical intensities under hypoxia (p ≤ 0.03, ES ≥ 0.33). TMG appears effective at detecting slight changes in the muscle contractile properties at moderate altitude. Further research involving TMG along with other muscle function assessment methods is needed to provide additional insight into peripheral neuromuscular alterations at moderate altitude.

  10. Muscle activation patterns during walking from transtibial amputees recorded within the residual limb-prosthetic interface

    PubMed Central

    2012-01-01

    Background Powered lower limb prostheses could be more functional if they had access to feedforward control signals from the user’s nervous system. Myoelectric signals are one potential control source. The purpose of this study was to determine if muscle activation signals could be recorded from residual lower limb muscles within the prosthetic socket-limb interface during walking. Methods We recorded surface electromyography from three lower leg muscles (tibilias anterior, gastrocnemius medial head, gastrocnemius lateral head) and four upper leg muscles (vastus lateralis, rectus femoris, biceps femoris, and gluteus medius) of 12 unilateral transtibial amputee subjects and 12 non-amputee subjects during treadmill walking at 0.7, 1.0, 1.3, and 1.6 m/s. Muscle signals were recorded from the amputated leg of amputee subjects and the right leg of control subjects. For amputee subjects, lower leg muscle signals were recorded from within the limb-socket interface and from muscles above the knee. We quantified differences in the muscle activation profile between amputee and control groups during treadmill walking using cross-correlation analyses. We also assessed the step-to-step inter-subject variability of these profiles by calculating variance-to-signal ratios. Results We found that amputee subjects demonstrated reliable muscle recruitment signals from residual lower leg muscles recorded within the prosthetic socket during walking, which were locked to particular phases of the gait cycle. However, muscle activation profile variability was higher for amputee subjects than for control subjects. Conclusion Robotic lower limb prostheses could use myoelectric signals recorded from surface electrodes within the socket-limb interface to derive feedforward commands from the amputee’s nervous system. PMID:22882763

  11. Lower extremity muscle activity during deep-water running on self-determined pace.

    PubMed

    Kaneda, Koichi; Wakabayashi, Hitoshi; Sato, Daisuke; Uekusa, Tamotsu; Nomura, Takeo

    2008-12-01

    Although deep-water running (DWR) is often used to obtain the benefits of aerobic fitness and to reduce vertical component stress, its attendant muscle stress remains unclear. The present study investigated lower extremity muscle activity and during DWR compared to that during land walking (LW) and water walking (WW). Surface electromyography was used to evaluate muscle activity in nine healthy adults during each exercise at self-determined slow, moderate, and fast paces. The duration of swing phase, ankle, knee and hip joint angle, and each joint range of motion (ROM) also investigated. Results show that the percentages of maximal voluntary contraction (%MVC) of the soleus and medial gastrocnemius were lower during DWR than during LW or WW in the backward swing phase. The %MVC of the rectus femoris was higher during WW and DWR than during LW; that of the vastus lateralis was lower during WW and DWR than during LW in the forward swing phase. In the biceps femoris, the %MVC was higher during DWR than during LW or WW in the forward and backward swing phase. Every pace showed a similar trend. These results suggest that DWR can stimulate the hip joint flexor or extensor muscles.

  12. The influence of the run intensity on bioelectrical activity of selected human leg muscles.

    PubMed

    Mastalerz, Andrzej; Gwarek, Lucyna; Sadowski, Jerzy; Szczepański, Tadeusz

    2012-01-01

    The purpose of this work was to investigate the electromyographic (EMG) fatigue representations in muscles of male runners during run at different level of intensity. In this study, the EMG signals for the rectus femoris and biceps femoris (long head) were collected by bipolar electrodes from the left and right lower extremities. EMG measurements were recorded during the run on tartan athletic track. Four professional athletes had to run a 400 m distance with a different intensity. The first distance of 400 m took 90 s; the second, 70 s; the third, 60 s; and the last one was covered with a maximal velocity until exhaustion. Power spectral analysis of EMG signals was carried out to calculate MPF. The results of our study revealed the efforts of different intensity for each muscle individually. The effect of fatigue was observed only in the case of running with the highest velocity. The biggest changes in MPF were observed for BF (23.6%) and RF (19.5%) muscles of the left leg and then for BF (17.5%) and RF (12.5%) ones of the right leg. We supposed that those differences between the right and left legs were mainly due to the curve of the track where those muscles are differently loaded.

  13. Muscle reaction function of individuals with intellectual disabilities may be improved through therapeutic use of a horse.

    PubMed

    Giagazoglou, Paraskevi; Arabatzi, Fotini; Kellis, Eleftherios; Liga, Maria; Karra, Chrisanthi; Amiridis, Ioannis

    2013-09-01

    Reaction time and muscle activation deficits might limit the individual's autonomy in activities of daily living and in participating in recreational activities. The aim of the present study was to assess the effects of a 14-week hippotherapy exercise program on movement reaction time and muscle activation in adolescents with intellectual disability (ID). Nineteen adolescents with moderate ID were assigned either to an experimental group (n=10) or a control group (n=9). The experimental group attended a hippotherapy exercise program, consisting of two 30-min sessions per week for 14 weeks. Reaction time, time of maximum muscle activity and electromyographic activity (EMG) of rectus femoris and biceps femoris when standing up from a chair under three conditions: in response to audio, visual and audio with closed eyes stimuli were measured. Analysis of variance designs showed that hippotherapy intervention program resulted in significant improvements in reaction time and a reduction in time to maximum muscle activity of the intervention group comparing to the control group in all 3 three conditions that were examined (p<0.05). The present findings suggest that the muscle reaction function of individuals with ID can be improved through hippotherapy training. Hippotherapy probably creates a changing environment with a variety of stimuli that enhance deep proprioception as well as other sensory inputs. In conclusion, this study provides evidence that hippotherapy can improve functional task performance by enhancing reaction time. PMID:23747935

  14. Muscle reaction function of individuals with intellectual disabilities may be improved through therapeutic use of a horse.

    PubMed

    Giagazoglou, Paraskevi; Arabatzi, Fotini; Kellis, Eleftherios; Liga, Maria; Karra, Chrisanthi; Amiridis, Ioannis

    2013-09-01

    Reaction time and muscle activation deficits might limit the individual's autonomy in activities of daily living and in participating in recreational activities. The aim of the present study was to assess the effects of a 14-week hippotherapy exercise program on movement reaction time and muscle activation in adolescents with intellectual disability (ID). Nineteen adolescents with moderate ID were assigned either to an experimental group (n=10) or a control group (n=9). The experimental group attended a hippotherapy exercise program, consisting of two 30-min sessions per week for 14 weeks. Reaction time, time of maximum muscle activity and electromyographic activity (EMG) of rectus femoris and biceps femoris when standing up from a chair under three conditions: in response to audio, visual and audio with closed eyes stimuli were measured. Analysis of variance designs showed that hippotherapy intervention program resulted in significant improvements in reaction time and a reduction in time to maximum muscle activity of the intervention group comparing to the control group in all 3 three conditions that were examined (p<0.05). The present findings suggest that the muscle reaction function of individuals with ID can be improved through hippotherapy training. Hippotherapy probably creates a changing environment with a variety of stimuli that enhance deep proprioception as well as other sensory inputs. In conclusion, this study provides evidence that hippotherapy can improve functional task performance by enhancing reaction time.

  15. BICEP2 constrains composite inflation

    NASA Astrophysics Data System (ADS)

    Channuie, Phongpichit

    2014-07-01

    In light of BICEP2, we re-examine single field inflationary models in which the inflation is a composite state stemming from various four-dimensional strongly coupled theories. We study in the Einstein frame a set of cosmological parameters, the primordial spectral index ns and tensor-to-scalar ratio r, predicted by such models. We confront the predicted results with the joint Planck data, and with the recent BICEP2 data. We constrain the number of e-foldings for composite models of inflation in order to obtain a successful inflation. We find that the minimal composite inflationary model is fully consistent with the Planck data. However it is in tension with the recent BICEP2 data. The observables predicted by the glueball inflationary model can be consistent with both Planck and BICEP2 contours if a suitable number of e-foldings are chosen. Surprisingly, the super Yang-Mills inflationary prediction is significantly consistent with the Planck and BICEP2 observations.

  16. Not all instability training devices enhance muscle activation in highly resistance-trained individuals.

    PubMed

    Wahl, Michael J; Behm, David G

    2008-07-01

    The objective of this study was to measure the electromyographic (EMG) activity of the soleus, bicep femoris, rectus femoris, lower abdominal, and lumbosacral erector spinae (LSES) muscles with a variety of (a) instability devices, (b) stable and unstable (Dyna Disc) exercises, and (c) a fatiguing exercise in 16 highly conditioned individuals. The device protocol had participants assume standing and squatting postures while balancing on a variety of unstable platforms (Dyna Disc, BOSU ball, wobble board, and a Swiss ball) and a stable floor. The exercise protocol had subjects performing, static front lunges, static side lunges, 1-leg hip extensions, 1-leg reaches, and calf raises on a floor or an unstable Dyna Disc. For the fatigue experiment, a wall sit position was undertaken under stable and unstable (BOSU ball) conditions. Results for the device experiment demonstrated increased activity for all muscles when standing on a Swiss ball and all muscles other than the rectus femoris when standing on a wobble board. Only lower abdominals and soleus EMG activity increased while squatting on a Swiss ball and wobble board. Devices such as the Dyna Disc and BOSU ball did not exhibit significant differences in muscle activation under any conditions, except the LSES in the standing Dyna Disc conditions. During the exercise protocol, there were no significant changes in muscle activity between stable and unstable (Dyna Disc) conditions. With the fatigue protocol, soleus EMG activity was 51% greater with a stable base. These results indicate that the use of moderately unstable training devices (i.e., Dyna Disc, BOSU ball) did not provide sufficient challenges to the neuromuscular system in highly resistance-trained individuals. Since highly trained individuals may already possess enhanced stability from the use of dynamic free weights, a greater degree of instability may be necessary.

  17. Patterns of muscle coordination during stepping responses post-stroke.

    PubMed

    Gray, V L; Pollock, C L; Wakeling, J M; Ivanova, T D; Garland, S J

    2015-12-01

    This study compared self-induced stepping reactions of seventeen participants after stroke and seventeen controls. Surface electromyographic (EMG) signals were recorded bilaterally from the soleus (SOL), tibialis anterior (TA), biceps femoris (BF) and rectus femoris (RF) muscles. Principal component analysis (PCA) was used to reduce the data into muscle activation patterns and examine group differences (paretic, non-paretic, control leg). The first principal component (PC1) explained 46.7% of the EMG signal of the stepping leg. Two PCs revealed distinct activation features for the stepping paretic leg: earlier TA onset at step initiation and earlier BF and SOL onset at mid-step. For the stance leg, PC1 explained 44.4% of the EMG signal and significant differences were found in the non-paretic leg compared to paretic (p < 0.001) and control (p < 0.001). In PC1, at step onset the BF and SOL EMG and the RF and TA EMG were increased over the latter half of the step. No PC loadings were distinct for the paretic leg during stance, however differences were found in the non-paretic leg: earlier TA burst and increased BF and SOL EMG at step initiation. The results suggest impairments in the paretic leg when stepping and compensatory strategies in the non-paretic stance leg. PMID:26475243

  18. Evaluation of muscle injury using magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    LeBlanc, A. D.; Jaweed, M.; Evans, H.

    1993-01-01

    The objective of this study was to investigate spin echo T2 relaxation time changes in thigh muscles after intense eccentric exercise in healthy men. Spin echo and calculated T2 relaxation time images of the thighs were obtained on several occasions after exercise of one limb; the contralateral limb served as control. Muscle damage was verified by elevated levels of serum creatine kinase (CK). Thirty percent of the time no exercise effect was discernible on the magnetic resonance (MR) images. In all positive MR images (70%) the semitendinosus muscle was positive, while the biceps femoris, short head, and gracilis muscles were also positive in 50% and 25% of the total cases, respectively. The peak T2 relaxation time and serum CK were correlated (r = 0.94, p<0.01); temporal changes in muscle T2 relaxation time and serum CK were similar, although T2 relaxation time remained positive after serum CK returned to background levels. We conclude that magnetic resonance imaging can serve as a useful tool in the evaluation of eccentric exercise muscle damage by providing a quantitative indicator of damage and its resolution as well as the specific areas and muscles.

  19. Tenderization potential of Hanwoo beef muscles from carcasses with differed genders and loin intramuscular fat content levels during post mortem ageing.

    PubMed

    Park, Beom Young; Seong, Pil Nam; Ba, Hoa Van; Park, Kyoung Mi; Cho, Soo Hyun; Moon, Sung Sil; Kang, Geun Ho

    2015-06-01

    Carcasses from Hanwoo steers (n = 15) and cows (n = 15) were classified into three groups: group 1 (G1), the carcasses had 10% to < 11.5% intramuscular fat (IMF) in loin muscles; group 2 (G2), the carcasses had 13% to < 4.5% IMF in loin muscles; and group 3(G3), the carcasses had 17% to < 18.5% IMF in loin muscles. These were used to evaluate the effects of gender and carcass group on quality traits and Warner-Bratzler shear force (WBSF) of Psoas major (PM), Longissimus thoracis (LT), Longissimus lumborum (LL), Longus colli (LC), Supraspinatus (SS), Latissimus dorsi (LAD), Semimembranosus (SM), Quadriceps femoris (QF), Biceps femoris (BF) and Semitendinosus (ST) muscles. Our results showed that pH values of LT, LL, LC, BF and QF muscles were lower in steers than in cows (P < 0.05). Water holding capacity (WHC) was found higher in LC, SS, LAD and QF muscles of steers (P < 0.05). At day 2 of ageing, gender affected the WBSF values of only PM, LD and QF muscles in G1, and QF muscle in G3; however, with additional ageing, the gender effect was observed for most of the muscles. Most muscles showed ageing responses; however, the rates of ageing response significantly varied depending on gender and carcass groups. The muscles of G1 and G2 had generally higher tenderization potentials than those of G3. Furthermore, most muscles in G3 had generally lower WBSF values than in G1 and G2. These results clearly indicate that ageing has a significant effect on quality and WBSF of beef muscles, and the classification by loin IMF level may be useful for prediction of the tenderness of other muscles.

  20. Altered lower leg muscle activation patterns in patients with cerebral palsy during cycling on an ergometer

    PubMed Central

    Alves-Pinto, Ana; Blumenstein, Tobias; Turova, Varvara; Lampe, Renée

    2016-01-01

    Objective Cycling on a recumbent ergometer constitutes one of the most popular rehabilitation exercises in cerebral palsy (CP). However, no control is performed on how muscles are being used during training. Given that patients with CP present altered muscular activity patterns during cycling or walking, it is possible that an incorrect pattern of muscle activation is being promoted during rehabilitation cycling. This study investigated patterns of muscular activation during cycling on a recumbent ergometer in patients with CP and whether those patterns are determined by the degree of spasticity and of mobility. Methods Electromyographic (EMG) recordings of lower leg muscle activation during cycling on a recumbent ergometer were performed in 14 adult patients diagnosed with CP and five adult healthy participants. EMG recordings were done with an eight-channel EMG system built in the laboratory. The activity of the following muscles was recorded: Musculus rectus femoris, Musculus biceps femoris, Musculus tibialis anterior, and Musculus gastrocnemius. The degree of muscle spasticity and mobility was assessed using the Modified Ashworth Scale and the Gross Motor Function Classification System, respectively. Muscle activation patterns were described in terms of onset and duration of activation as well as duration of cocontractions. Results Muscle activation in CP was characterized by earlier onsets, longer periods of activation, a higher occurrence of agonist–antagonist cocontractions, and a more variable cycling tempo in comparison to healthy participants. The degree of altered muscle activation pattern correlated significantly with the degree of spasticity. Conclusion This study confirmed the occurrence of altered lower leg muscle activation patterns in patients with CP during cycling on a recumbent ergometer. There is a need to develop feedback systems that can inform patients and therapists of an incorrect muscle activation during cycling and support the training

  1. Proximal Biceps in Overhead Athletes.

    PubMed

    Chalmers, Peter N; Verma, Nikhil N

    2016-01-01

    The proximal long head of the biceps tendon and its attachment at the superior glenoid tubercle and labrum are subject to a spectrum of disorders in overhead athletes. Biceps disorders are commonly characterized by intermittent anterior or deep-seated shoulder pain exacerbated by activity. Diagnosis is reached via various physical examination maneuvers; MRI can be uncertain. Nonsteroidal anti-inflammatory medications, targeted ultrasound-guided corticosteroid injections, and supervised physical therapy are the mainstays of nonoperative treatment. Operative treatment, which remains controversial, provides reliable pain relief, restoration of function for activities of daily living, and low complication rates, but return to play can be unpredictable.

  2. Iontophoretic transport kinetics of ketorolac in vitro and in vivo: demonstrating local enhanced topical drug delivery to muscle.

    PubMed

    Gratieri, Taís; Pujol-Bello, Ester; Gelfuso, Guilherme M; de Souza, Joel G; Lopez, Renata F V; Kalia, Yogeshvar N

    2014-02-01

    The objective of the study was to investigate the iontophoretic delivery kinetics of ketorolac (KT), a highly potent NSAID and peripherally-acting analgesic that is currently indicated to treat moderate to severe acute pain. It was envisaged that, depending on the amounts delivered, transdermal iontophoretic administration might have two distinct therapeutic applications: (i) more effective and faster local therapy with shorter onset times (e.g. to treat trauma-related pain/inflammation in muscle) or (ii) a non-parenteral, gastrointestinal tract sparing approach for systemic pain relief. The first part of the study investigated the effect of experimental conditions on KT iontophoresis using porcine and human skin in vitro. These results demonstrated that KT electrotransport was linearly dependent on current density - from 0.1875 to 0.5mA/cm(2) - (r(2)>0.99) and drug concentration - from 5 to 20mg/ml (r(2)>0.99). Iontophoretic permeation of KT from a 2% hydroxymethyl cellulose gel was comparable to that from an aqueous solution with equivalent drug loading (584.59±114.67 and 462.05±66.56μg/cm(2), respectively). Cumulative permeation (462.05±66.56 and 416.28±95.71μg/cm(2)) and steady state flux (106.72±11.70 and 94.28±15.47μg/cm(2)h), across porcine and human skin, were statistically equivalent confirming the validity of the model. Based on the results in vitro, it was decided to focus on topical rather than systemic applications of KT iontophoresis in vivo. Subsequent experiments, in male Wistar rats, investigated the local enhancement of KT delivery to muscle by iontophoresis. Drug biodistribution was assessed in skin, in the biceps femoris muscle beneath the site of iontophoresis ('treated muscle'; TM), in the contralateral muscle ('non-treated muscle'; NTM) and in plasma (P). Passive topical delivery and oral administration served as negative and positive controls, respectively. Iontophoretic administration for 30min was superior to passive topical

  3. Bilateral Congenital Agenesis of the Long Head of the Biceps Tendon: The Beginning

    PubMed Central

    Rego Costa, Francisco; Esteves, Cátia; Melão, Lina

    2016-01-01

    The biceps brachii muscle is prone to variants but absence of the long head of the biceps (LHB) tendon is an exceptionally rare anomaly. This report concerns the fourth case of bilateral congenital absence of the LHB tendon and presents the ultrasonography (US) and magnetic resonance (MR) findings. Our case has the peculiarity of being the first in which bilateral LHB tendon agenesis is not associated with rotator cuff or labral tears. PMID:26904345

  4. Advances in quantitative muscle ultrasonography using texture analysis of ultrasound images.

    PubMed

    Molinari, Filippo; Caresio, Cristina; Acharya, U Rajendra; Mookiah, Muthu Rama Krishnan; Minetto, Marco Alessandro

    2015-09-01

    Musculoskeletal ultrasound imaging can be used to investigate the skeletal muscle structure in terms of architecture (thickness, cross-sectional area, fascicle length and fascicle pennation angle) and texture. Gray-scale analysis is commonly used to characterize transverse scans of the muscle. Gray mean value is used to distinguish between normal and pathologic muscles, but it depends on the image acquisition system and its settings. In this study, quantitative ultrasonography was performed on five muscles (biceps brachii, vastus lateralis, rectus femoris, medial gastrocnemius and tibialis anterior) of 20 healthy patients (10 women, 10 men) to assess the characterization performance of higher-order texture descriptors to differentiate genders and muscle types. A total of 53 features (7 first-order descriptors, 24 Haralick features, 20 Galloway features and 2 local binary pattern features) were extracted from each muscle region of interest (ROI) and were used to perform the multivariate linear regression analysis (MANOVA). Our results show that first-order descriptors, Haralick features (energy, entropy and correlation measured along different angles) and local binary pattern (LBP) energy and entropy were highly linked to the gender, whereas Haralick entropy and symmetry, Galloway texture descriptors and LBP entropy helped to distinguish muscle types. Hence, the combination of first-order and higher-order texture descriptors (Haralick, Galloway and LBP) can be used to discriminate gender and muscle types. Therefore, multi-texture analysis may be useful to investigate muscle damage and myopathic disorders.

  5. Progressive muscle proteome changes in a clinically relevant pig model of Duchenne muscular dystrophy.

    PubMed

    Fröhlich, Thomas; Kemter, Elisabeth; Flenkenthaler, Florian; Klymiuk, Nikolai; Otte, Kathrin A; Blutke, Andreas; Krause, Sabine; Walter, Maggie C; Wanke, Rüdiger; Wolf, Eckhard; Arnold, Georg J

    2016-01-01

    Duchenne muscular dystrophy (DMD) is caused by genetic deficiency of dystrophin and characterized by massive structural and functional changes of skeletal muscle tissue, leading to terminal muscle failure. We recently generated a novel genetically engineered pig model reflecting pathological hallmarks of human DMD better than the widely used mdx mouse. To get insight into the hierarchy of molecular derangements during DMD progression, we performed a proteome analysis of biceps femoris muscle samples from 2-day-old and 3-month-old DMD and wild-type (WT) pigs. The extent of proteome changes in DMD vs. WT muscle increased markedly with age, reflecting progression of the pathological changes. In 3-month-old DMD muscle, proteins related to muscle repair such as vimentin, nestin, desmin and tenascin C were found to be increased, whereas a large number of respiratory chain proteins were decreased in abundance in DMD muscle, indicating serious disturbances in aerobic energy production and a reduction of functional muscle tissue. The combination of proteome data for fiber type specific myosin heavy chain proteins and immunohistochemistry showed preferential degeneration of fast-twitch fiber types in DMD muscle. The stage-specific proteome changes detected in this large animal model of clinically severe muscular dystrophy provide novel molecular readouts for future treatment trials. PMID:27634466

  6. Progressive muscle proteome changes in a clinically relevant pig model of Duchenne muscular dystrophy

    PubMed Central

    Fröhlich, Thomas; Kemter, Elisabeth; Flenkenthaler, Florian; Klymiuk, Nikolai; Otte, Kathrin A.; Blutke, Andreas; Krause, Sabine; Walter, Maggie C.; Wanke, Rüdiger; Wolf, Eckhard; Arnold, Georg J.

    2016-01-01

    Duchenne muscular dystrophy (DMD) is caused by genetic deficiency of dystrophin and characterized by massive structural and functional changes of skeletal muscle tissue, leading to terminal muscle failure. We recently generated a novel genetically engineered pig model reflecting pathological hallmarks of human DMD better than the widely used mdx mouse. To get insight into the hierarchy of molecular derangements during DMD progression, we performed a proteome analysis of biceps femoris muscle samples from 2-day-old and 3-month-old DMD and wild-type (WT) pigs. The extent of proteome changes in DMD vs. WT muscle increased markedly with age, reflecting progression of the pathological changes. In 3-month-old DMD muscle, proteins related to muscle repair such as vimentin, nestin, desmin and tenascin C were found to be increased, whereas a large number of respiratory chain proteins were decreased in abundance in DMD muscle, indicating serious disturbances in aerobic energy production and a reduction of functional muscle tissue. The combination of proteome data for fiber type specific myosin heavy chain proteins and immunohistochemistry showed preferential degeneration of fast-twitch fiber types in DMD muscle. The stage-specific proteome changes detected in this large animal model of clinically severe muscular dystrophy provide novel molecular readouts for future treatment trials. PMID:27634466

  7. Advances in quantitative muscle ultrasonography using texture analysis of ultrasound images.

    PubMed

    Molinari, Filippo; Caresio, Cristina; Acharya, U Rajendra; Mookiah, Muthu Rama Krishnan; Minetto, Marco Alessandro

    2015-09-01

    Musculoskeletal ultrasound imaging can be used to investigate the skeletal muscle structure in terms of architecture (thickness, cross-sectional area, fascicle length and fascicle pennation angle) and texture. Gray-scale analysis is commonly used to characterize transverse scans of the muscle. Gray mean value is used to distinguish between normal and pathologic muscles, but it depends on the image acquisition system and its settings. In this study, quantitative ultrasonography was performed on five muscles (biceps brachii, vastus lateralis, rectus femoris, medial gastrocnemius and tibialis anterior) of 20 healthy patients (10 women, 10 men) to assess the characterization performance of higher-order texture descriptors to differentiate genders and muscle types. A total of 53 features (7 first-order descriptors, 24 Haralick features, 20 Galloway features and 2 local binary pattern features) were extracted from each muscle region of interest (ROI) and were used to perform the multivariate linear regression analysis (MANOVA). Our results show that first-order descriptors, Haralick features (energy, entropy and correlation measured along different angles) and local binary pattern (LBP) energy and entropy were highly linked to the gender, whereas Haralick entropy and symmetry, Galloway texture descriptors and LBP entropy helped to distinguish muscle types. Hence, the combination of first-order and higher-order texture descriptors (Haralick, Galloway and LBP) can be used to discriminate gender and muscle types. Therefore, multi-texture analysis may be useful to investigate muscle damage and myopathic disorders. PMID:26026375

  8. Changes in muscle activation patterns in response to enhanced sensory input during treadmill stepping in infants born with myelomeningocele

    PubMed Central

    Pantall, Annette; Teulier, Caroline; Ulrich, Beverly D.

    2013-01-01

    Infants with myelomeningocele (MMC) increase step frequency in response to modifications to the treadmill surface. The aim was to investigate how these modifications impacted the electromyographic (EMG) patterns. We analyzed EMG from 19 infants aged 2–10 months, with MMC at the lumbosacral level. We supported infants upright on the treadmill for 12 trials, each 30 seconds long. Modifications included visual flow, unloading, weights, Velcro and lcriction. Surface electrodes recorded EMG from tibialis anterior, lateral gastrocnemius, rectus femoris and biceps femoris. We determined muscle bursts for each stride cycle and from these calculated various parameters. Results indicated that each of the five sensory conditions generated different motor patterns. Visual flow and friction which we previously reported increased step frequency impacted lateral gastrocnemius most. Weights, which significantly decreased step frequency increased burst duration and co-activity of the proximal muscles. We also observed an age effect, with all conditions increasing muscle activity in younger infants whereas in older infants visual flow and unloading stimulated most activity. In conclusion, we have demonstrated that infants with myelomeningocele at levels which impact the myotomes of major locomotor muscles find ways to respond and adapt their motor output to changes in sensory input. PMID:23158017

  9. Changes in muscle activation patterns in response to enhanced sensory input during treadmill stepping in infants born with myelomeningocele.

    PubMed

    Pantall, Annette; Teulier, Caroline; Ulrich, Beverly D

    2012-12-01

    Infants with myelomeningocele (MMC) increase step frequency in response to modifications to the treadmill surface. The aim was to investigate how these modifications impacted the electromyographic (EMG) patterns. We analyzed EMG from 19 infants aged 2-10 months, with MMC at the lumbosacral level. We supported infants upright on the treadmill for 12 trials, each 30 seconds long. Modifications included visual flow, unloading, weights, Velcro and lcriction. Surface electrodes recorded EMG from tibialis anterior, lateral gastrocnemius, rectus femoris and biceps femoris. We determined muscle bursts for each stride cycle and from these calculated various parameters. Results indicated that each of the five sensory conditions generated different motor patterns. Visual flow and friction which we previously reported increased step frequency impacted lateral gastrocnemius most. Weights, which significantly decreased step frequency increased burst duration and co-activity of the proximal muscles. We also observed an age effect, with all conditions increasing muscle activity in younger infants whereas in older infants visual flow and unloading stimulated most activity. In conclusion, we have demonstrated that infants with myelomeningocele at levels which impact the myotomes of major locomotor muscles find ways to respond and adapt their motor output to changes in sensory input.

  10. Muscle activity amplitudes and co-contraction during stair ambulation following anterior cruciate ligament reconstruction.

    PubMed

    Hall, Michelle; Stevermer, Catherine A; Gillette, Jason C

    2015-04-01

    The purpose of this study was to compare muscle activity amplitudes and co-contraction in those with anterior cruciate ligament (ACL) reconstruction to healthy controls during stair negotiation. Eighteen participants with unilateral ACL reconstruction and 17 healthy controls performed stair ascent and descent while surface electromyography was recorded from knee and hip musculature. During stair ascent, the ACL group displayed higher gluteus maximus activity (1-50% stance, p = 0.02), higher vastus lateralis:biceps femoris co-contraction (51-100% stance, p = 0.01), and higher vastus lateralis:vastus medialis co-contraction (51-100% stance, p = 0.05). During stair descent, the ACL group demonstrated higher gluteus maximus activity (1-50% stance, p = 0.01; 51-100% stance, p < 0.01), lower rectus femoris activity (1-50% stance, p = 0.04), higher semimembranosus activity (1-50% stance, p=0.01), higher gluteus medius activity (51-100% stance, p = 0.01), and higher vastus medialis:semimembranosus co-contraction (1-50% stance, p = 0.02). While the altered muscle activity strategies observed in the ACL group may act to increase joint stability, these strategies may alter joint loading and contribute to post-traumatic knee osteoarthritis often observed in this population. Our results warrant further investigation to determine the longterm effects of altered muscle activity on the knee joint following ACL reconstruction.

  11. Oxygen uptake, muscle activity and ground reaction force during water aerobic exercises.

    PubMed

    Alberton, C L; Pinto, S S; Cadore, E L; Tartaruga, M P; Kanitz, A C; Antunes, A H; Finatto, P; Kruel, L F M

    2014-12-01

    This study aimed to compare the oxygen uptake (VO2), the muscle activity of lower limbs, and the vertical ground reaction force (V-GRF) of women performing water aerobic exercises at different intensities. 12 young women performed the experimental protocol, which consisted of 3 water exercises (stationary running [SR], frontal kick [FK] and cross country skiing [CCS]) at 3 intensities (first and second ventilatory thresholds and maximum effort). A two-way repeated measures ANOVA was used. Regarding VO2, different responses between intensities (p<0.001) were found, and values between exercises were similar. For electromyographic activity (EMG), differences between intensities for all muscles (p<0.001) were found. Greater EMG signals were observed in the FK compared to SR for rectus femoris, semitendinosus, vastus lateralis and biceps femoris muscles (p<0.05). Regarding V-GRF, there was an increase in the V-GRF at greater intensities compared to the first ventilatory threshold (p=0.001). In addition, lower values were found during CCS compared to the SR and FK exercises (p<0.001). Thus, greater cardiorespiratory and neuromuscular responses were observed with increasing intensity. Exercises such as CCS could be used to attenuate the V-GRF; if the purpose is to reduce the muscular activity of lower limbs at a specific intensity, SR could be recommended.

  12. The effect of swinging the arms on muscle activation and production of leg force during ski skating at different skiing speeds.

    PubMed

    Göpfert, Caroline; Lindinger, Stefan J; Ohtonen, Olli; Rapp, Walter; Müller, Erich; Linnamo, Vesa

    2016-06-01

    The study investigated the effects of arm swing during leg push-off in V2-alternate/G4 skating on neuromuscular activation and force production by the leg muscles. Nine skilled cross-country skiers performed V2-alternate skating without poles at moderate, high, and maximal speeds, both with free (SWING) and restricted arm swing (NOSWING). Maximal speed was 5% greater in SWING (P<0.01), while neuromuscular activation and produced forces did not differ between techniques. At both moderate and high speed the maximal (2% and 5%, respectively) and average (both 5%) vertical force and associated impulse (10% and 14%) were greater with SWING (all P<0.05). At high speed range of motion and angular velocity of knee flexion were 24% greater with SWING (both P<0.05), while average EMG of m. biceps femoris was 31% lower (all P<0.05) in SWING. In a similar manner, the average EMG of m. vastus medialis and m. biceps femoris were lower (17% and 32%, P<0.05) during the following knee extension. Thus, swinging the arms while performing V2-alternate can enhance both maximal speed and skiing economy at moderate and, in particularly, high speeds.

  13. Lower Extremity Muscle Activity During a Women's Overhand Lacrosse Shot.

    PubMed

    Millard, Brianna M; Mercer, John A

    2014-06-28

    The purpose of this study was to describe lower extremity muscle activity during the lacrosse shot. Participants (n=5 females, age 22±2 years, body height 162.6±15.2 cm, body mass 63.7±23.6 kg) were free from injury and had at least one year of lacrosse experience. The lead leg was instrumented with electromyography (EMG) leads to measure muscle activity of the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (GA). Participants completed five trials of a warm-up speed shot (Slow) and a game speed shot (Fast). Video analysis was used to identify the discrete events defining specific movement phases. Full-wave rectified data were averaged per muscle per phase (Crank Back Minor, Crank Back Major, Stick Acceleration, Stick Deceleration). Average EMG per muscle was analyzed using a 4 (Phase) × 2 (Speed) ANOVA. BF was greater during Fast vs. Slow for all phases (p<0.05), while TA was not influenced by either Phase or Speed (p>0.05). RF and GA were each influenced by the interaction of Phase and Speed (p<0.05) with GA being greater during Fast vs. Slow shots during all phases and RF greater during Crank Back Minor and Major as well as Stick Deceleration (p<0.05) but only tended to be greater during Stick Acceleration (p=0.076) for Fast vs. Slow. The greater muscle activity (BF, RF, GA) during Fast vs. Slow shots may have been related to a faster approach speed and/or need to create a stiff lower extremity to allow for faster upper extremity movements. PMID:25114727

  14. Walking at the preferred stride frequency minimizes muscle activity.

    PubMed

    Russell, Daniel M; Apatoczky, Dylan T

    2016-03-01

    This study determined whether walking at the preferred stride frequency minimizes muscle activity compared with other cadences at the same speed. Anthropometric measurements were recorded from 10 subjects and used to estimate their predicted resonant stride frequency. The preferred walking speed and stride frequency were determined from freely adopted walking on a treadmill. For the experimental trials the treadmill was set at each individual's preferred walking speed. Participants walked for 6 min at eight cadences prescribed by an auditory metronome: preferred stride frequency and -35, -25, -15, 0, +15, +25, +35% of predicted resonant stride frequency. Oxygen consumption was measured via gas analysis. Muscle activity of the right leg gastrocnemius (GA), tibialis anterior (TA), biceps femoris (BF) and rectus femoris (RF) muscles was recorded via electromyography (EMG). On average, participants preferred to walk with a stride frequency .07 Hz lower than their predicted resonant stride frequency, however a strong positive correlation was observed between these variables. Stride frequency had a significant and large quadratic effect on VO2 (RLR(2)=.76), and activity of the GA (RLR(2)=.66), TA (RLR(2)=.83), BF (RLR(2)=.70) and RF (RLR(2)=.78) muscles. VO2, GA and TA activity were all minimal at the preferred stride frequency and increased for faster or slower cadences. BF and RF activity were minimal across a broad range of slow frequencies including the preferred stride frequency and increased for faster frequencies. The preferred stride frequency that humans readily adopt during walking minimizes the activation of the GA, TA, BF and RF muscles, which in turn minimizes the overall metabolic cost. PMID:26979903

  15. Molecular characterization and expression patterns of Lbx1 in porcine skeletal muscle.

    PubMed

    Chao, Zhe; Wu, Jian; Zheng, Rong; Li, Feng-E; Xiong, Yuan-Zhu; Deng, Chang-Yan

    2011-08-01

    Ladybird-like genes were recently identified in mammals. The first member characterized, Lbx1, is expressed in developing skeletal muscle and the nervous system. However, little is known about the porcine Lbx1 gene. In the present study, we cloned and characterized Lbx1 from porcine muscle. RT-PCR analyses showed that Lbx1 was highly expressed in porcine skeletal muscle tissues. And we provide the first evidence that Lbx1 has a certain regulated expression pattern during the postnatal period of the porcine skeletal muscle development. Lbx1 gene expressed at higher levels in biceps femoris muscles compared with masseter, semitendinosus and longissimus dorsi muscles in Meishan pigs. Phylogenetic tree was constructed by aligning the amino acid sequences of different species. Moreover, single nucleotide polymorphism (SNP) scanning in the Lbx1 genomic fragment identified two mutations, g.752A>G and g.-1559C>G. Association analysis in our experimental pig populations showed that the mutation of g.752A>G was significantly associated with loin muscle area (P<0.05) and internal fat rate (P<0.05). Our results suggest that the Lbx1 gene might be a candidate gene of carcass traits and provide useful information for further studies on its roles in porcine skeletal muscle.

  16. Muscular coordination of biceps brachii and brachioradialis in elbow flexion with respect to hand position

    PubMed Central

    Kleiber, Tim; Kunz, Leo; Disselhorst-Klug, Catherine

    2015-01-01

    Contribution of synergistic muscles toward specific movements over multi joint systems may change with varying position of distal or proximal joints. Purpose of this study is to reveal the relationship of muscular coordination of brachioradialis and biceps brachii during elbow flexion with respect to hand position and biomechanical advantages and disadvantages of biceps brachii. A group of 16 healthy subjects has been advised to perform 20 repetitions of single elbow flexion movements in different hand positions (pronated, neutral, and supinated). With a speed of 20°/s, simultaneously sEMG of biceps brachii and brachioradialis and kinematics of the movement were recorded in a motion analysis laboratory. Normalized to MVC the sEMG amplitudes of both muscles contributing to elbow flexion movements were compared in pronated, supinated, and neutral hand position over elbow joint angle. Significant differences in the contribution of brachioradialis were found in pronated hand position compared to supinated and neutral hand position while the muscular activity of biceps brachii shows no significant changes in any hand position. In conclusion, a statistical significant dependency of the inter-muscular coordination between biceps brachii and brachioradialis during elbow flexion with respect to hand position has been observed depending on a biomechanical disadvantage of biceps brachii. PMID:26300781

  17. A preliminary study on the differences in male and female muscle force distribution patterns during squatting and lunging maneuvers

    PubMed Central

    Hale, Rena; Hausselle, Jerome G.; Gonzalez, Roger V.

    2014-01-01

    In the United States, 250,000 people tear their anterior cruciate ligament (ACL) annually with females at higher risk of ACL failure then males. By predicting muscle forces during low impact maneuvers we may be able to estimate possible muscle imbalances that could lead to ACL failure during highly dynamic maneuvers. The purpose of this initial study was to predict muscle forces in males and females similar in size and activity level, during squat and lunge maneuvers. We hypothesized that during basic low impact maneuvers (a) distribution of quadriceps forces are different in males and females and (b) females exhibit quadriceps dominance when compared to males. Two males and three females performed squatting and lunging maneuvers while electromyography (EMG) data, motion capture data, and ground reaction forces were collected. Nine individual muscle forces for muscles that cross the knee were estimated using an EMG-driven model. Results suggest that males activate more their rectus femoris muscle than females, who in turn activate more their vastus lateralis muscle at their maximum flexion angle, and more their vastus medialis muscle when ascending from a squat. During the lunge maneuver, males used greater biceps femoris force than females, throughout the lunge, and females exhibited higher semitendinosus force. Quadriceps dominance was evident in both males and females during the prescribed tasks, and there was no statistical difference between genders. Understanding individual muscle force distributions in males and females during low impact maneuvers may provide insights regarding failure mechanisms during highly dynamic maneuvers, when ACL injuries are more prevalent. PMID:25016289

  18. The effect of stance width on the electromyographical activity of eight superficial thigh muscles during back squat with different bar loads.

    PubMed

    Paoli, Antonio; Marcolin, Giuseppe; Petrone, Nicola

    2009-01-01

    Many strength trainers believe that varying the stance width during the back squat can target specific muscles of the thigh. The aim of the present work was to test this theory measuring the activation of 8 thigh muscles while performing back squats at 3 stance widths and with 3 different bar loads. Six experienced lifters performed 3 sets of 10 repetitions of squats, each one with a different stance width, using 3 resistances: no load, 30% of 1-repetition maximum (1RM), and 70% 1RM. Sets were separated by 6 minutes of rest. Electromyographic (EMG) surface electrodes were placed on the vastus medialis, vastus lateralis, rectus femoris, semitendinosus, biceps femoris, gluteus maximus, gluteus medium, and adductor maior. Analysis of variance and Scheffè post hoc tests indicated a significant difference in EMG activity only for the gluteus maximus; in particular, there was a higher electrical activity of this muscle when back squats were performed at the maximum stance widths at 0 and 70% 1RM. There were no significant differences concerning the EMG activity of the other analyzed muscles. These findings suggest that a large width is necessary for a greater activation of the gluteus maximus during back squats. PMID:19130646

  19. Bicep2. III. INSTRUMENTAL SYSTEMATICS

    SciTech Connect

    Ade, P. A. R.; Aikin, R. W.; Bock, J. J.; Brevik, J. A.; Filippini, J. P.; Golwala, S. R.; Hildebrandt, S. R.; Barkats, D.; Benton, S. J.; Bischoff, C. A.; Buder, I.; Karkare, K. S.; Bullock, E.; Dowell, C. D.; Duband, L.; Fliescher, S.; Halpern, M.; Hasselfield, M.; Hilton, G. C.; Irwin, K. D.; Collaboration: Bicep2 Collaboration; and others

    2015-12-01

    In a companion paper, we have reported a >5σ detection of degree scale B-mode polarization at 150 GHz by the Bicep2 experiment. Here we provide a detailed study of potential instrumental systematic contamination to that measurement. We focus extensively on spurious polarization that can potentially arise from beam imperfections. We present a heuristic classification of beam imperfections according to their symmetries and uniformities, and discuss how resulting contamination adds or cancels in maps that combine observations made at multiple orientations of the telescope about its boresight axis. We introduce a technique, which we call “deprojection,” for filtering the leading order beam-induced contamination from time-ordered data, and show that it reduces power in Bicep2's actual and null-test BB spectra consistent with predictions using high signal-to-noise beam shape measurements. We detail the simulation pipeline that we use to directly simulate instrumental systematics and the calibration data used as input to that pipeline. Finally, we present the constraints on BB contamination from individual sources of potential systematics. We find that systematics contribute BB power that is a factor of ∼10× below Bicep2's three-year statistical uncertainty, and negligible compared to the observed BB signal. The contribution to the best-fit tensor/scalar ratio is at a level equivalent to r = (3–6) × 10{sup −3}.

  20. BICEP2 III: Instrumental systematics

    SciTech Connect

    Ade, P. A. R.

    2015-11-23

    In a companion paper, we have reported a >5σ detection of degree scale B-mode polarization at 150 GHz by the Bicep2 experiment. Here we provide a detailed study of potential instrumental systematic contamination to that measurement. We focus extensively on spurious polarization that can potentially arise from beam imperfections. We present a heuristic classification of beam imperfections according to their symmetries and uniformities, and discuss how resulting contamination adds or cancels in maps that combine observations made at multiple orientations of the telescope about its boresight axis. We introduce a technique, which we call "deprojection," for filtering the leading order beam-induced contamination from time-ordered data, and show that it reduces power in Bicep2's actual and null-test BB spectra consistent with predictions using high signal-to-noise beam shape measurements. We detail the simulation pipeline that we use to directly simulate instrumental systematics and the calibration data used as input to that pipeline. Finally, we present the constraints on BB contamination from individual sources of potential systematics. We find that systematics contribute BB power that is a factor of ~10× below Bicep2's three-year statistical uncertainty, and negligible compared to the observed BB signal. Lastly, the contribution to the best-fit tensor/scalar ratio is at a level equivalent to r = (3–6) × 10–3.

  1. Bicep2 III: Instrumental Systematics

    NASA Astrophysics Data System (ADS)

    Bicep2 Collaboration; Ade, P. A. R.; Aikin, R. W.; Barkats, D.; Benton, S. J.; Bischoff, C. A.; Bock, J. J.; Brevik, J. A.; Buder, I.; Bullock, E.; Dowell, C. D.; Duband, L.; Filippini, J. P.; Fliescher, S.; Golwala, S. R.; Halpern, M.; Hasselfield, M.; Hildebrandt, S. R.; Hilton, G. C.; Irwin, K. D.; Karkare, K. S.; Kaufman, J. P.; Keating, B. G.; Kernasovskiy, S. A.; Kovac, J. M.; Kuo, C. L.; Leitch, E. M.; Lueker, M.; Netterfield, C. B.; Nguyen, H. T.; O'Brient, R.; Ogburn, R. W., IV; Orlando, A.; Pryke, C.; Richter, S.; Schwarz, R.; Sheehy, C. D.; Staniszewski, Z. K.; Sudiwala, R. V.; Teply, G. P.; Tolan, J. E.; Turner, A. D.; Vieregg, A. G.; Wong, C. L.; Yoon, K. W.

    2015-12-01

    In a companion paper, we have reported a >5σ detection of degree scale B-mode polarization at 150 GHz by the Bicep2 experiment. Here we provide a detailed study of potential instrumental systematic contamination to that measurement. We focus extensively on spurious polarization that can potentially arise from beam imperfections. We present a heuristic classification of beam imperfections according to their symmetries and uniformities, and discuss how resulting contamination adds or cancels in maps that combine observations made at multiple orientations of the telescope about its boresight axis. We introduce a technique, which we call “deprojection,” for filtering the leading order beam-induced contamination from time-ordered data, and show that it reduces power in Bicep2's actual and null-test BB spectra consistent with predictions using high signal-to-noise beam shape measurements. We detail the simulation pipeline that we use to directly simulate instrumental systematics and the calibration data used as input to that pipeline. Finally, we present the constraints on BB contamination from individual sources of potential systematics. We find that systematics contribute BB power that is a factor of ˜10× below Bicep2's three-year statistical uncertainty, and negligible compared to the observed BB signal. The contribution to the best-fit tensor/scalar ratio is at a level equivalent to r = (3-6) × 10-3.

  2. BICEP2 III: Instrumental systematics

    DOE PAGES

    Ade, P. A. R.

    2015-11-23

    In a companion paper, we have reported a >5σ detection of degree scale B-mode polarization at 150 GHz by the Bicep2 experiment. Here we provide a detailed study of potential instrumental systematic contamination to that measurement. We focus extensively on spurious polarization that can potentially arise from beam imperfections. We present a heuristic classification of beam imperfections according to their symmetries and uniformities, and discuss how resulting contamination adds or cancels in maps that combine observations made at multiple orientations of the telescope about its boresight axis. We introduce a technique, which we call "deprojection," for filtering the leading ordermore » beam-induced contamination from time-ordered data, and show that it reduces power in Bicep2's actual and null-test BB spectra consistent with predictions using high signal-to-noise beam shape measurements. We detail the simulation pipeline that we use to directly simulate instrumental systematics and the calibration data used as input to that pipeline. Finally, we present the constraints on BB contamination from individual sources of potential systematics. We find that systematics contribute BB power that is a factor of ~10× below Bicep2's three-year statistical uncertainty, and negligible compared to the observed BB signal. Lastly, the contribution to the best-fit tensor/scalar ratio is at a level equivalent to r = (3–6) × 10–3.« less

  3. Muscle activity while running at 20%-50% of normal body weight.

    PubMed

    Mercer, John A; Applequist, Bryon C; Masumoto, Kenji

    2013-01-01

    Little information exists on how body weight (BW) support influences running biomechanics. The study aim was to determine how reducing BW by 50%-80% influences muscle activity while running at different speeds. Subjects (n = 7) ran at 100%, 115%, 125% of preferred speed at 100%, 50%, 40%, 30%, 20% of BW per speed. Average (AVG) electromyography of the rectified signal was compared (within subject design; 3-speeds × 5-BW, repeated measures ANOVAs; biceps femoris [BF], rectus femoris [RF], tibialis anterior [TA], gastrocnemius [GA]). RF, BF, and GA AVG were not influenced by BW-speed interaction (p > .05) and increased across speeds (p < .05). RF and GA AVG signal was reduced as BW was reduced (p < .05), but BF only tended to be different (p = .08). TA was influenced by BW-speed interaction (p < .05) with EMG decreasing across BW (p < .05) while increasing across speeds except at 100% BW. Overall, muscle activity increased with speed and decreased by BW reductions.

  4. Cycling induced by electrical stimulation improves muscle activation and symmetry during pedaling in hemiparetic patients.

    PubMed

    Ambrosini, Emilia; Ferrante, Simona; Ferrigno, Giancarlo; Molteni, Franco; Pedrocchi, Alessandra

    2012-05-01

    A randomized controlled trial, involving 35 post-acute hemiparetic patients, demonstrated that a four-week treatment of cycling induced by functional electrical stimulation (FES-cycling) promotes motor recovery. Analyzing additional data acquired during that study, the present work investigated whether these improvements were associated to changes in muscle strength and motor coordination. Participants were randomized to receive FES-cycling or placebo FES-cycling. Clinical outcome measures were: the Motricity Index (MI), the gait speed, the electromyography activation of the rectus femoris and biceps femoris, and the mechanical work produced by each leg during voluntary pedaling. To provide a comparison with normal values, healthy adults also carried out the pedaling test. Patients were evaluated before, after training, and at follow-up visits. A significant treatment effect in favor of FES-treated patients was found in terms of MI scores and unbalance in mechanical works, while differences in gait speed were not significant (ANCOVA). Significant improvements in the activation of the paretic muscles were highlighted in the FES group, while no significant change was found in the placebo group (Friedman test). Our findings suggested that improvements in motor functions induced by FES-cycling training were associated with a more symmetrical involvement of the two legs and an improved motor coordination. PMID:22514205

  5. Vestibular actions on back and lower limb muscles during postural tasks in man

    PubMed Central

    Ali, Alima S; Rowen, Katherine A; Iles, J F

    2003-01-01

    The vestibular system was activated by galvanic electrical stimulation in 19 normal subjects. With the head turned to one side so that the stimulating anode was on the posterior mastoid process, stimulation caused standing subjects to sway backwards in the sagittal plane. Electromyography showed bilateral activation of erector spinae, gluteus maximus, biceps femoris, soleus and intrinsic foot (toe flexor) muscles. When head direction or electrode polarity was reversed so that the anode was anterior, all those muscles became less active and the subjects swayed forwards. With the head facing forward, stimulation caused sideways sway in the coronal plane, towards the anode, with excitation of the erector spinae on the anode side and reduced activity on the cathode side. The limb muscles were activated on the side opposite the anode and showed complex responses on the anode side. Responses were detectable in the erectores spinae muscles in sitting subjects. No responses in limb muscles were detected in the sitting posture. Subject responses in erector spinae recorded at L3/L4 had latencies from 59 to 110 ms, using a 2 mA stimulus. Latencies in lower limb muscles were longer. The results suggest a role for the vestibular system and descending brain stem motor pathways to the erectores spinae muscles in the control of postural orientation of the back when sitting and standing. The conduction velocity in the motor pathway was estimated to be 13 ± 10 m s−1 (mean ± s.d., n = 12 subjects). PMID:12527747

  6. Proximal rectus femoris avulsion in an elite, olympic-level sprinter.

    PubMed

    Langer, Phillip R; Selesnick, Harlan

    2010-11-01

    Quadriceps injuries, ranging from simple strains to disabling muscle ruptures, are common athletic injuries. The rectus femoris is the most commonly injure portion of the quadriceps musculature. This article is, to our knowledge, the first report of a proximal rectus femoris avulsion in an elite, Olympic-level 100-meter sprinter, acutely managed with surgical repair. Several key factors must be considered and carefully assessed when determining the appropriate course of management (ie, deciding between operative and nonoperative treatment): amount of distal retraction of the tendon, severity of associated soft-tissue trauma, physical examination, and postoperative goals (eg, return to elite-level competitive sports involving running or kicking vs resuming basic activities of daily living). We believe that these factors in our elite, high-performance athlete dictated an operative course of management.

  7. Progression and variation of fatty infiltration of the thigh muscles in Duchenne muscular dystrophy, a muscle magnetic resonance imaging study.

    PubMed

    Li, Wenzhu; Zheng, Yiming; Zhang, Wei; Wang, Zhaoxia; Xiao, Jiangxi; Yuan, Yun

    2015-05-01

    The purpose of this study was to assess the progression and variation of fatty infiltration of the thigh muscles of Duchenne muscular dystrophy patients. Muscle magnetic resonance imaging was used to measure the degree of fatty infiltration of the thigh muscles of 171 boys with Duchenne muscular dystrophy (mean age, 6.09 ± 2.30 years). Fatty infiltration was assigned using a modified Mercuri's scale 0-5 (normal-severe). The gluteus maximus and adductor magnus were affected in patients less than two years old, followed by the biceps femoris. Quadriceps and semimembranosus were first affected at the age of five to six years; the sartorius, gracilis and adductor longus remained apparently unaffected until seven years of age. Fatty infiltration of all the thigh muscles developed rapidly after seven years of age. The standard deviation of the fatty infiltration scores ranged from 2.41 to 4.87 before five years old, and from 6.84 to 11.66 between six and ten years old. This study provides evidence of highly variable degrees of fatty infiltration in children of different ages with Duchenne muscular dystrophy, and indicates that fatty infiltration progresses more quickly after seven years of age. These findings may be beneficial for the selection of therapeutic regimens and the analysis of future clinical trials.

  8. Relationships of thigh muscle contractile and non-contractile tissue with function, strength, and age in boys with Duchenne muscular dystrophy.

    PubMed

    Akima, Hiroshi; Lott, Donovan; Senesac, Claudia; Deol, Jasjit; Germain, Sean; Arpan, Ishu; Bendixen, Roxanna; Lee Sweeney, H; Walter, Glenn; Vandenborne, Krista

    2012-01-01

    The purpose of this study was to assess the contractile and non-contractile content in thigh muscles of patients with Duchenne muscular dystrophy (DMD) and determine the relationship with functional abilities. Magnetic resonance images of the thigh were acquired in 28 boys with DMD and 10 unaffected boys. Muscle strength, timed functional tests, and the Brookes Lower Extremity scale were also assessed. Non-contractile content in the DMD group was significantly greater than in the control group for six muscles, including rectus femoris, biceps femoris-long head and adductor magnus. Non-contractile content in the total thigh musculature assessed by MRI correlated with the Brookes scale (r(s)=0.75) and supine-up test (r(s)=0.68), as well as other functional measures. An age-related specific torque increase was observed in the control group (r(s)=0.96), but not the DMD (r(s)=0.06). These findings demonstrate that MRI measures of contractile and non-contractile content can provide important information about disease progression in DMD. PMID:21807516

  9. Unexpected motor patterns for hindlimb muscles during slope walking in the cat.

    PubMed

    Smith, J L; Carlson-Kuhta, P

    1995-11-01

    1. Hindlimb kinematics and motor patterns were assessed from high-speed ciné film synchronized with electromyographic (EMG) data from cats trained to walk on a walkway placed at four grades (25, 50, 75, and 100%). 2. Flexor muscles of the hip (iliopsoas) and ankle (tibialis anterior) had similar activity patterns for the swing phase of up- and down-slope walking; both flexor muscles also had stance-related activity during down-slope walking and this was unexpected. Extensor muscles of the hip (anterior biceps femoris and anterior semimembranosus), knee [vastus lateralis (VL)], and ankle [lateral gastrocnemius (LG)] were active during the stance phase of up-slope walking. The VL and LG activity was reduced in duration during stance of down-slope walking and centered around paw contact. Hip extensors, however, were totally inactive during stance of down-slope walking, and this was not expected. 3. Flexor muscles at the hip and ankle (not extensor muscles) dominated the stance phase of down-slope walking, especially at the steeper slopes. This switch in motor patterns may be required to counterbalance external forces that produced extension at the hip and ankle joints during the stance phase of down-slope walking. Neural mechanisms for programming stance-related activity of flexor muscles are discussed.

  10. Changes in Muscle Activity and Kinematics of Highly Trained Cyclists During Fatigue

    PubMed Central

    Dingwell, Jonathan B.; Joubert, Jason E.; Diefenthaeler, Fernando; Trinity, Joel D.

    2010-01-01

    Muscle fatigue may alter kinematics and contribute to repetitive strain injuries. This study quantified how both localized muscle fatigue and movement kinematics change over time during exhaustive cycling. Seven highly trained cyclists rode a stationary bicycle ergometer at 100% of their VO2max until voluntary exhaustion. Cycling kinematics and EMG activity from select lower extremity muscles were recorded. Cross-correlations were computed to quantify how EMG median frequencies (MDF) changed with changes in movement kinematics. All athletes maintained both cadence and power output for ~90% of the trial duration. Significant sustained muscle fatigue occurred in 18 of 28 muscles tested, most prominently in the biceps femoris (p = 0.020) and gastrocnemius (p = 0.018). Kinematics and MDF both fluctuated non-monotonically as subjects fatigued. Changes in MDF significantly preceded changes in mean trunk lean (p = 0.009) and hip angles (p = 0.025), and trunk lean range of motion (p = 0.029). Fluctuations in MDF were positively correlated with fluctuations in mean trunk lean (p = 0.009) and knee splay angles (p = 0.011), and with trunk lean (p = 0.002) and ankle (p = 0.001) range of motion. These results therefore establish a direct link between changes in muscle fatigue state and subsequent changes in movement kinematics during cycling.. PMID:18990638

  11. Changes in muscle activity after performing the FIFA 11+ programme part 2 for 4 weeks.

    PubMed

    Takata, Yasushi; Nakase, Junsuke; Inaki, Anri; Mochizuki, Takafumi; Numata, Hitoaki; Oshima, Takeshi; Kinuya, Seigo; Tsuchiya, Hiroyuki

    2016-10-01

    Changes in muscle activity were evaluated by positron emission tomography-computed tomography (PET-CT) after performing part 2 of the Fédération Internationale de Football Association's 11+ programme (11+) for 4 weeks. Eleven males performed part 2 of the 11+ for 20 min before and after 37 MBq of (18)F-fluorodeoxyglucose (FDG) was injected intravenously. PET-CT images were obtained 50 min after FDG injection. The participants were then instructed to perform part 2 of the 11+ 3 times per week for 4 consecutive weeks, after which another set of PET-CT images was obtained following the same procedure. Regions of interest were defined within 30 muscles. The standardised uptake value (SUV) of FDG by muscle tissue per unit volume was calculated, and FDG accumulation was compared between pre- and post-training PET-CT results. Performing part 2 of the 11+ for 4 weeks increased mean SUV in the sartorius, semimembranosus, biceps femoris, abductor hallucis, and flexor hallucis brevis muscles (P < 0.05). In conclusion, routinely performing part 2 of the 11+ for 4 weeks increased glucose uptake related to muscle activity in the hamstrings and hallux muscles. We speculate that there is some possibility of this change of muscle activity contributing to a decrease in sports-related injuries.

  12. The Influence of an Unstable Surface on Trunk and Lower Extremity Muscle Activities during Variable Bridging Exercises

    PubMed Central

    Kim, Jung-hyun; Kim, Young; Chung, Yijung

    2014-01-01

    [Purpose] The aim of this study was to investigate the influence of an unstable surface on trunk and lower extremity muscle activities during various types of bridging exercises. [Subjects] Thirty healthy female adults voluntarily participated in this study. [Methods] All subjects were asked to perform 3 different bridging exercises (bridging exercise, single leg lift bridging exercise, single leg cross bridging exercise) with and without an unstable surface. The trunk and lower extremity muscle activities were measured by using surface electromyography during bridging exercise. [Results] During the bridging exercise (BE), single leg lift bridging exercise (LBE), and single leg cross bridging exercise (CBE), the muscle activities of the external oblique muscle (EO), erector spinae (ES), and biceps femoris (BF) were significantly higher on an unstable surface than on a stable surface. The muscle activities of the EO on both sides, contralateral BF, and ipsilateral ES were significantly higher during LBE than during BE and CBE. [Conclusion] Use of an unstable surface increases muscle activity of the trunk and lower extremities, and single leg lift bridging exercise increases the muscle activity of the EO on both sides, ipsilateral ES, and contralateral BF. PMID:24764625

  13. Influence of type of muscle on volatile compounds throughout the manufacture of Celta dry-cured ham.

    PubMed

    Bermúdez, Roberto; Franco, Daniel; Carballo, Javier; Lorenzo, José M

    2015-12-01

    The effect of muscle type on volatile compounds throughout the manufacture of Celta dry-cured ham was studied. Thirty Celta ham were taken from the fresh pieces, after the end of the salting stage, after 120 days of post-salting, after the end of drying-ripening stage, and after 165 and 330 days of "bodega" step. The volatile compounds from semimembranosus (SM) and biceps femoris (BF) muscles were extracted by using headspace-solid phase microextraction (SPME) and analysed by gas chromatographic/mass spectrometry (GC/MS). Fifty-five volatile compounds were identified and quantified. The number of volatile compounds increased during the different steps of the process, reaching at 550 days of process 39 and 40 volatile compounds in SM and BF muscles, respectively. Results indicated that the most abundant chemical family in flavour at the end of the manufacturing process were esters in the two muscles studied, followed by aliphatic hydrocarbons and aldehydes. During the manufacturing process, an increase in the total amount of volatile compounds was observed, being this increase more marked in samples from BF muscle (from 550.7 to 1118.9 × 10(6) area units) than in samples from SM muscle (from 459.3 to 760.4 × 10(6) area units). Finally, muscle type displayed significant (P < 0.05) differences for four esters, two alcohols, one aldehyde, one ketone and four aliphatic hydrocarbons. PMID:25331495

  14. Whole-body vibration effects on the muscle activity of upper and lower body muscles during the baseball swing in recreational baseball hitters.

    PubMed

    Reyes, Gabriel F; Dickin, D Clark; Crusat, Nolan J K; Dolny, Dennis G

    2011-11-01

    The purpose of this study was to evaluate the effects of whole-body vibration (WBV) on the muscle recruitment of selected upper and lower body muscles during the baseball swing. Participants were recreationally trained males (n = 16, 22 +/- 2 years, 181.4 +/- 7.4 cm, 84.7 +/- 9.0 kg), with previous baseball experience. Subjects participated in three randomized sessions on separate days, consisting of three sets of five swings offa hitting tee. Exercises (upper and lower body dynamic and static movements) with or without WBVexposure were performed between swing sets. During each swing, the gastrocnemius, biceps femoris, gluteus maximus, pectoralis major, latissimus dorsi, and triceps brachii were evaluated for electromyographic (EMG) activity. EMG values were normalized to EMG measured during maximal voluntary isometric contraction. Statistical analysis revealed no significant differences in EMG activity across the three treatments. In addition, the results displayed a specific muscle recruitment order during the swing, starting with the lower body followed by the upper body muscles. This study was the first to report the recruitment order during the baseball swing. Although acute exposure to WBV did not significantly alter the muscle recruitment, these results may prove useful for practitioners looking to enhance baseball swing performance. PMID:22303781

  15. Whole-body vibration effects on the muscle activity of upper and lower body muscles during the baseball swing in recreational baseball hitters.

    PubMed

    Reyes, Gabriel F; Dickin, D Clark; Crusat, Nolan J K; Dolny, Dennis G

    2011-11-01

    The purpose of this study was to evaluate the effects of whole-body vibration (WBV) on the muscle recruitment of selected upper and lower body muscles during the baseball swing. Participants were recreationally trained males (n = 16, 22 +/- 2 years, 181.4 +/- 7.4 cm, 84.7 +/- 9.0 kg), with previous baseball experience. Subjects participated in three randomized sessions on separate days, consisting of three sets of five swings offa hitting tee. Exercises (upper and lower body dynamic and static movements) with or without WBVexposure were performed between swing sets. During each swing, the gastrocnemius, biceps femoris, gluteus maximus, pectoralis major, latissimus dorsi, and triceps brachii were evaluated for electromyographic (EMG) activity. EMG values were normalized to EMG measured during maximal voluntary isometric contraction. Statistical analysis revealed no significant differences in EMG activity across the three treatments. In addition, the results displayed a specific muscle recruitment order during the swing, starting with the lower body followed by the upper body muscles. This study was the first to report the recruitment order during the baseball swing. Although acute exposure to WBV did not significantly alter the muscle recruitment, these results may prove useful for practitioners looking to enhance baseball swing performance.

  16. Changes in diffusion tensor imaging (DTI) eigenvalues of skeletal muscle due to hybrid exercise training.

    PubMed

    Okamoto, Yoshikazu; Kemp, Graham J; Isobe, Tomonori; Sato, Eisuke; Hirano, Yuji; Shoda, Junichi; Minami, Manabu

    2014-12-01

    Several studies have proposed the cell membrane as the main water diffusion restricting factor in the skeletal muscle cell. We sought to establish whether a particular form of exercise training (which is likely to affect only intracellular components) could affect water diffusion. The purpose of this study is to characterise prospectively the changes in diffusion tensor imaging (DTI) eigenvalues of thigh muscle resulting from hybrid training (HYBT) in patients with non-alcoholic fatty liver disease (NAFLD). Twenty-one NAFLD patients underwent HYBT for 30 minutes per day, twice a week for 6 months. Patients were scanned using DTI of the thigh pre- and post-HYBT. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), the three eigenvalues lambda 1 (λ1), λ2, λ3, and the maximal cross sectional area (CSA) were measured in bilateral thigh muscles: knee flexors (biceps femoris (BF), semitendinosus (ST), semimembranous (SM)) and knee extensors (medial vastus (MV), intermediate vastus (IV), lateral vastus (LV), and rectus femoris (RF)), and compared pre- and post-HYBT by paired t-test. Muscle strength of extensors (P<0.01), but not flexors, increased significantly post-HYBT. For FA, ADC and eigenvalues, the overall picture was of increase. Some (P<0.05 in λ2 and P<0.01 in λ1) eigenvalues of flexors and all (λ1-λ3) eigenvalues of extensors increased significantly (P<0.01) post-HYBT. HYBT increased all 3 eigenvalues. We suggest this might be caused by enlargement of muscle intracellular space.

  17. Lower Extremity Muscle Activity During a Women’s Overhand Lacrosse Shot

    PubMed Central

    Millard, Brianna M.; Mercer, John A.

    2014-01-01

    The purpose of this study was to describe lower extremity muscle activity during the lacrosse shot. Participants (n=5 females, age 22±2 years, body height 162.6±15.2 cm, body mass 63.7±23.6 kg) were free from injury and had at least one year of lacrosse experience. The lead leg was instrumented with electromyography (EMG) leads to measure muscle activity of the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (GA). Participants completed five trials of a warm-up speed shot (Slow) and a game speed shot (Fast). Video analysis was used to identify the discrete events defining specific movement phases. Full-wave rectified data were averaged per muscle per phase (Crank Back Minor, Crank Back Major, Stick Acceleration, Stick Deceleration). Average EMG per muscle was analyzed using a 4 (Phase) × 2 (Speed) ANOVA. BF was greater during Fast vs. Slow for all phases (p<0.05), while TA was not influenced by either Phase or Speed (p>0.05). RF and GA were each influenced by the interaction of Phase and Speed (p<0.05) with GA being greater during Fast vs. Slow shots during all phases and RF greater during Crank Back Minor and Major as well as Stick Deceleration (p<0.05) but only tended to be greater during Stick Acceleration (p=0.076) for Fast vs. Slow. The greater muscle activity (BF, RF, GA) during Fast vs. Slow shots may have been related to a faster approach speed and/or need to create a stiff lower extremity to allow for faster upper extremity movements. PMID:25114727

  18. Grazing-induced changes in muscle microRNA-206 and -208b expression in association with myogenic gene expression in cattle.

    PubMed

    Horikawa, Akihiko; Ogasawara, Hideki; Okada, Kaito; Kobayashi, Misato; Muroya, Susumu; Hojito, Masayuki

    2015-11-01

    To investigate the roles of microRNAs (miRNAs) in muscle type conversion, the effects of 4 months of grazing on the expression levels of miRNAs and mRNAs associated with skeletal muscle development were analyzed by quantitative RT-PCR using the Biceps femoris muscle of Japanese Shorthorn cattle. After 4 months of grazing, the expression of muscle fiber type-associated miR-208b was higher in the grazed cattle than in the housed. In concordance with the pattern in miR-208b expression, the expression of MyoD, a myogenic regulatory factor associated with the shifting of muscle property to the fast type, was lower in the grazed cattle after 4 months of grazing than in the housed cattle. In addition, the expression of MyHC-2x (a fast type) was higher in the housed cattle than in the grazed, after 4 months of grazing. During the grazing period, miR-206 expression decreased in the housed cattle, whereas expression in the grazed cattle did not change, but rather remained higher than that of the housed cattle even at 3 months after the grazing ended. These miRNAs including miR-206 persisting with muscles of grazed cattle may be associated with regulation of muscle gene expression during skeletal muscle adaptation to grazing.

  19. EMG characteristics and fibre composition: study on rectus femoris of sprinters and long distance runners.

    PubMed

    Goswami, A; Sadhukhan, A K; Gupta, S

    2001-10-01

    The study was conducted on 9 sprinters and 5 long distance runners to investigate the difference in power spectral characteristics of rectus femoris muscle and the feasibility of using electromyographic techniques in categorization of muscle groups in slow dominant and fast dominant types. EMG signal was recorded, after digitization at 4 KHz, from rectus femoris muscle during isometric knee extension (at maximum voluntary contraction level) until fatigue. Digitized signal was processed for Fast Fourier Transform and Root Mean Square (RMS) voltage. Significant difference (P < 0.05) was found in RMS voltage between sprinters and long distance runners. Both groups showed decline in Mean Power Frequency (MPE) and rate of decline in sprinters was rapid. Normalized MPF showed better discrimination between the two groups. It is concluded that the EMG response observed in this study was possibly a result of differences in the muscle fibre composition of the athletes. EMG study using spectral characteristics would be useful in categorizing the sports persons in terms of suitability of the events.

  20. Relationship between skin temperature and muscle activation during incremental cycle exercise.

    PubMed

    Priego Quesada, Jose I; Carpes, Felipe P; Bini, Rodrigo R; Salvador Palmer, Rosario; Pérez-Soriano, Pedro; Cibrián Ortiz de Anda, Rosa M

    2015-02-01

    While different studies showed that better fitness level adds to the efficiency of the thermoregulatory system, the relationship between muscular effort and skin temperature is still unknown. Therefore, the present study assessed the relationship between neuromuscular activation and skin temperature during cycle exercise. Ten physically active participants performed an incremental workload cycling test to exhaustion while neuromuscular activations were recorded (via surface electromyography - EMG) from rectus femoris, vastus lateralis, biceps femoris and gastrocnemius medialis. Thermographic images were recorded before, immediately after and 10 min after finishing the cycling test, at four body regions of interest corresponding to the muscles where neuromuscular activations were monitored. Frequency band analysis was conducted to assess spectral properties of EMG signals in order to infer on priority in recruitment of motor units. Significant inverse relationship between changes in skin temperature and changes in overall neuromuscular activation for vastus lateralis was observed (r<-0.5 and p<0.04). Significant positive relationship was observed between skin temperature and low frequency components of neuromuscular activation from vastus lateralis (r>0.7 and p<0.01). Participants with larger overall activation and reduced low frequency component for vastus lateralis activation presented a better adaptive response of their thermoregulatory system by showing fewer changes in skin temperature after incremental cycling test.

  1. Muscle activation during various hamstring exercises.

    PubMed

    McAllister, Matt J; Hammond, Kelley G; Schilling, Brian K; Ferreria, Lucas C; Reed, Jacob P; Weiss, Lawrence W

    2014-06-01

    The dorsal muscles of the lower torso and extremities have often been denoted the "posterior chain." These muscles are used to support the thoracic and lumbar spine and peripheral joints, including the hip, knee, and ankle on the dorsal aspect of the body. This study investigated the relative muscle activity of the hamstring group and selected surrounding musculature during the leg curl, good morning, glute-ham raise, and Romanian deadlift (RDL). Twelve healthy, weight-trained men performed duplicate trials of single repetitions at 85% 1-repetition maximum for each lift in random order, during which surface electromyography and joint angle data were obtained. Repeated measures analysis of variance across the 4 exercises was performed to compare the activity from the erector spinae (ES), gluteus medius (GMed), semitendinosus (ST), biceps femoris (BF), and medial gastrocnemius (MGas). Significant differences (p ≤ 0.05) were noted in eccentric muscle activity between exercise for the MGas (p < 0.027), ST (p < 0.001), BF (p < 0.001), and ES (p = 0.032), and in concentric muscle activity, for the ES (p < 0.001), BF (p = 0.010), ST (p = 0.009), MGas (p < 0.001), and the GMed (p = 0.018). Bonferroni post hoc analysis revealed significant pairwise differences during eccentric actions for the BF, ST, and MGas. Post hoc analysis also revealed significant pairwise differences during concentric actions for the ES, BF, ST, MGas, and GMed. Each of these showed effect sizes that are large or greater. The main findings of this investigation are that the ST is substantially more active than the BF among all exercises, and hamstring activity was maximized in the RDL and glute-ham raise. Therefore, athletes and coaches who seek to maximize the involvement of the hamstring musculature should consider focusing on the glute-ham raise and RDL. PMID:24149748

  2. Age and Diet Affect Gene Expression Profile in Canine Skeletal Muscle

    PubMed Central

    Middelbos, Ingmar S.; Vester, Brittany M.; Karr-Lilienthal, Lisa K.; Schook, Lawrence B.; Swanson, Kelly S.

    2009-01-01

    We evaluated gene transcription in canine skeletal muscle (biceps femoris) using microarray analysis to identify effects of age and diet on gene expression. Twelve female beagles were used (six 1-year olds and six 12-year olds) and they were fed one of two experimental diets for 12 months. One diet contained primarily plant-based protein sources (PPB), whereas the second diet contained primarily animal-based protein sources (APB). Affymetrix GeneChip Canine Genome Arrays were used to hybridize extracted RNA. Age had the greatest effect on gene transcription (262 differentially expressed genes), whereas the effect of diet was relatively small (22 differentially expressed genes). Effects of age (regardless of diet) were most notable on genes related to metabolism, cell cycle and cell development, and transcription function. All these genes were predominantly down-regulated in geriatric dogs. Age-affected genes that were differentially expressed on only one of two diets were primarily noted in the PPB diet group (144/165 genes). Again, genes related to cell cycle (22/35) and metabolism (15/19) had predominantly decreased transcription in geriatric dogs, but 6/8 genes related to muscle development had increased expression. Effects of diet on muscle gene expression were mostly noted in geriatric dogs, but no consistent patterns in transcription were observed. The insight these data provide into gene expression profiles of canine skeletal muscle as affected by age, could serve as a foundation for future research pertaining to age-related muscle diseases. PMID:19221602

  3. Effect of ski simulator training on kinematic and muscle activation of the lower extremities

    PubMed Central

    Moon, Jeheon; Koo, Dohoon; Kim, Kitae; Shin, Insik; Kim, Hyeyoung; Kim, Jinhae

    2015-01-01

    [Purpose] This study aimed to verify the effectiveness of an augmented reality-based ski simulator through analyzing the changes in movement patterns as well as the engagement of major muscles of the lower body. [Subjects] Seven subjects participated in the study. All were national team-level athletes studying at “K” Sports University in Korea who exhibited comparable performance levels and had no record of injuries in the preceding 6 months (Age 23.4 ± 3.8 years; Height 172.6 ± 12.1 cm; Weight 72.3 ± 16.2 kg; Experience 12.3 ± 4.8 years). [Methods] A reality-based ski simulator developed by a Korean manufacturer was used for the study. Three digital video cameras and a wireless electromyography system were used to perform 3-dimensional motion analysis and measure muscle activation level. [Results] Left hip angulation was found to increase as the frequency of the turns increased. Electromyography data revealed that the activation level of the quadriceps group’s extension muscles and the biceps femoris group’s flexing muscles had a crossing pattern. [Conclusion] Sustained training using an augmented reality-based ski simulator resulted in movements that extended the lower body joints, which is thought to contribute to increasing muscle fatigue. PMID:26357449

  4. Influence of muscle type on physicochemical and sensory properties of foal meat.

    PubMed

    Lorenzo, José M; Pateiro, Mirian; Franco, Daniel

    2013-05-01

    The effect of muscle type on physico-chemical properties and sensory characteristics of foal meat was investigated. Six muscles: longissimus dorsi (LD), semimembranosus (SM), semitendinosus (ST), biceps femoris (BF), triceps brachii (TB) and psoas major &minor (PM) from twelve foals slaughtered at 15 months from an extensive production system in freedom regimen were extracted for this study. Regarding chemical composition, intramuscular fat content showed significant differences among muscle where PM presented higher values (0.7%) than the other ones. The heme-iron content also presented significant differences ranging between 1.5 and 2.4mg/100g fresh meat. ST was the lightest, while TB and PM presented a more intense redness. The muscles that had a greater capacity to hold water were ST and BF, which presented lower drip loss (2 and 2.2%) and cooking loss (17.3 and 17.2%), respectively. Textural traits established the following scale in response to the tenderness: LD>PM>ST>TB>BF>SM. Finally, sensory analyses revealed that color and texture traits (hardness, juiciness and fibrousness) were significantly influenced by muscle type.

  5. Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1

    PubMed Central

    Tasca, Giorgio; D'Amico, Adele; Monforte, Mauro; Nadaj-Pakleza, Aleksandra; Vialle, Marc; Fattori, Fabiana; Vissing, John; Ricci, Enzo; Bertini, Enrico

    2015-01-01

    Tubular aggregate myopathy is a genetically heterogeneous disease characterized by tubular aggregates as the hallmark on muscle biopsy. Mutations in STIM1 have recently been identified as one genetic cause in a number of tubular aggregate myopathy cases. To characterize the pattern of muscle involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not caused by mutations in STIM1. A common pattern of involvement was found in STIM1-mutated patients, although with variable extent and severity of lesions. In the upper girdle, the subscapularis muscle was invariably affected. In the lower limbs, all the patients showed a consistent involvement of the flexor hallucis longus, which is very rarely affected in other muscle diseases, and a diffuse involvement of thigh and posterior leg with sparing of gracilis, tibialis anterior and, to a lesser extent, short head of biceps femoris. Mutations in STIM1 are associated with a homogeneous involvement on imaging despite variable clinical features. Muscle imaging can be useful in identifying STIM1-mutated patients especially among other forms of tubular aggregate myopathy. PMID:26255678

  6. Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1.

    PubMed

    Tasca, Giorgio; D'Amico, Adele; Monforte, Mauro; Nadaj-Pakleza, Aleksandra; Vialle, Marc; Fattori, Fabiana; Vissing, John; Ricci, Enzo; Bertini, Enrico

    2015-11-01

    Tubular aggregate myopathy is a genetically heterogeneous disease characterized by tubular aggregates as the hallmark on muscle biopsy. Mutations in STIM1 have recently been identified as one genetic cause in a number of tubular aggregate myopathy cases. To characterize the pattern of muscle involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not caused by mutations in STIM1. A common pattern of involvement was found in STIM1-mutated patients, although with variable extent and severity of lesions. In the upper girdle, the subscapularis muscle was invariably affected. In the lower limbs, all the patients showed a consistent involvement of the flexor hallucis longus, which is very rarely affected in other muscle diseases, and a diffuse involvement of thigh and posterior leg with sparing of gracilis, tibialis anterior and, to a lesser extent, short head of biceps femoris. Mutations in STIM1 are associated with a homogeneous involvement on imaging despite variable clinical features. Muscle imaging can be useful in identifying STIM1-mutated patients especially among other forms of tubular aggregate myopathy. PMID:26255678

  7. Effect of ski simulator training on kinematic and muscle activation of the lower extremities.

    PubMed

    Moon, Jeheon; Koo, Dohoon; Kim, Kitae; Shin, Insik; Kim, Hyeyoung; Kim, Jinhae

    2015-08-01

    [Purpose] This study aimed to verify the effectiveness of an augmented reality-based ski simulator through analyzing the changes in movement patterns as well as the engagement of major muscles of the lower body. [Subjects] Seven subjects participated in the study. All were national team-level athletes studying at "K" Sports University in Korea who exhibited comparable performance levels and had no record of injuries in the preceding 6 months (Age 23.4 ± 3.8 years; Height 172.6 ± 12.1 cm; Weight 72.3 ± 16.2 kg; Experience 12.3 ± 4.8 years). [Methods] A reality-based ski simulator developed by a Korean manufacturer was used for the study. Three digital video cameras and a wireless electromyography system were used to perform 3-dimensional motion analysis and measure muscle activation level. [Results] Left hip angulation was found to increase as the frequency of the turns increased. Electromyography data revealed that the activation level of the quadriceps group's extension muscles and the biceps femoris group's flexing muscles had a crossing pattern. [Conclusion] Sustained training using an augmented reality-based ski simulator resulted in movements that extended the lower body joints, which is thought to contribute to increasing muscle fatigue.

  8. Glenoid labrum tears related to the long head of the biceps.

    PubMed

    Andrews, J R; Carson, W G; McLeod, W D

    1985-01-01

    Tears of the glenoid labrum were observed in 73 baseball pitchers and other throwing athletes who underwent arthroscopic examination of the dominant shoulder. Most of the tears were located over the anterosuperior portion of the glenoid labrum near the origin of the tendon of the long head of the biceps muscle into the glenoid. At arthroscopy, the tendon of the long head of the biceps appeared to originate through and be continuous with the superior portion of the glenoid labrum. In many cases it appeared to have pulled the anterosuperior portion of the labrum off the glenoid. This observation was verified at arthroscopy by viewing the origin of the biceps tendon into the glenoid labrum as the muscle was electrically stimulated. With stimulation of the muscle, the tendinous portion became quite taut, particularly near its attachment to the glenoid labrum, and actually lifted the labrum off the glenoid. Three-dimensional high-speed cinematography with computer analysis revealed that the moment acting about the elbow joint to extend the joint through an arc of about 50 degrees was in excess of 600 inch-pounds. The extremely high velocity of elbow extension which is generated must be decelerated through the final 30 degrees of elbow extension. Of the muscles of the arm that provide the large deceleration forces in the follow-through phase of throwing, only the biceps brachii traverses both the elbow joint and the shoulder joint. Additional forces are generated in the biceps tendon in its function as a "shunt" muscle to stabilize the glenohumeral joint during the throwing act.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Glenoid labrum tears related to the long head of the biceps.

    PubMed

    Andrews, J R; Carson, W G; McLeod, W D

    1985-01-01

    Tears of the glenoid labrum were observed in 73 baseball pitchers and other throwing athletes who underwent arthroscopic examination of the dominant shoulder. Most of the tears were located over the anterosuperior portion of the glenoid labrum near the origin of the tendon of the long head of the biceps muscle into the glenoid. At arthroscopy, the tendon of the long head of the biceps appeared to originate through and be continuous with the superior portion of the glenoid labrum. In many cases it appeared to have pulled the anterosuperior portion of the labrum off the glenoid. This observation was verified at arthroscopy by viewing the origin of the biceps tendon into the glenoid labrum as the muscle was electrically stimulated. With stimulation of the muscle, the tendinous portion became quite taut, particularly near its attachment to the glenoid labrum, and actually lifted the labrum off the glenoid. Three-dimensional high-speed cinematography with computer analysis revealed that the moment acting about the elbow joint to extend the joint through an arc of about 50 degrees was in excess of 600 inch-pounds. The extremely high velocity of elbow extension which is generated must be decelerated through the final 30 degrees of elbow extension. Of the muscles of the arm that provide the large deceleration forces in the follow-through phase of throwing, only the biceps brachii traverses both the elbow joint and the shoulder joint. Additional forces are generated in the biceps tendon in its function as a "shunt" muscle to stabilize the glenohumeral joint during the throwing act.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:4051091

  10. Impact of season on the fatty acid profiles of male and female blesbok (Damaliscus pygargus phillipsi) muscles.

    PubMed

    Neethling, J; Britz, T J; Hoffman, L C

    2014-12-01

    This study quantified the impact of season on fatty acid profiles of male and female blesbok muscles (longissimus thoracis et lumborum, biceps femoris, semimembranosus, semitendinosus, infraspinatus, and supraspinatus). Eight mature blesbok were harvested per season (winter and spring). Gender and muscle type influenced (p<0.05) the fatty acid profiles of blesbok muscles, while season only influenced the C18:3ω3 (α-linolenic acid, ALA) percentages and therefore the total omega-3 poly-unsaturated fatty acids (total ω3 PUFA). Female muscles had higher C16:0 (palmitic acid) (21.01%±0.256 vs. 19.05%±0.296) and total MUFA percentages, while male muscles had higher (p<0.05) C18:2ω6c, C20:5ω3, total ω3 PUFA (11.08%±0.382 vs. 8.50%±0.367), and total PUFA (43.03%±0.904 vs. 29.59%±1.164) percentages, contributing to higher poly-unsaturated to saturated fatty acid ratios (PUFA:SFA ratios). Differences in fatty acid profiles were attributed more to gender and anatomical location of muscles, than seasonal differences in diets. PMID:25089783

  11. Focusing on Increasing Velocity during Heavy Resistance Knee Flexion Exercise Boosts Hamstring Muscle Activity in Chronic Stroke Patients

    PubMed Central

    Jakobsen, Markus D.

    2016-01-01

    Background. Muscle strength is markedly reduced in stroke patients, which has negative implications for functional capacity and work ability. Different types of feedback during strength training exercises may alter neuromuscular activity and functional gains. Objective. To compare levels of muscle activity during conditions of blindfolding and intended high contraction speed with a normal condition of high-intensity knee flexions. Methods. Eighteen patients performed unilateral machine knee flexions with a 10-repetition maximum load. Surface electromyography (EMG) was recorded from the quadrics and hamstring muscles and normalized to maximal EMG (nEMG) of the nonparetic limb. Results. For the paretic leg, the speed condition showed higher values of muscle activity compared with the normal and blindfolded conditions for both biceps femoris and semitendinosus. Likewise, the speed condition showed higher co-contraction values compared with the normal and blindfolded conditions for the vastus lateralis. No differences were observed between exercise conditions for the nonparetic leg. Conclusion. Chronic stroke patients are capable of performing heavy resistance training with intended high speed of contraction. Focusing on speed during the concentric phase elicited higher levels of muscle activity of the hamstrings compared to normal and blindfolded conditions, which may have implications for regaining fast muscle strength in stroke survivors. PMID:27525118

  12. Focusing on Increasing Velocity during Heavy Resistance Knee Flexion Exercise Boosts Hamstring Muscle Activity in Chronic Stroke Patients.

    PubMed

    Vinstrup, Jonas; Calatayud, Joaquin; Jakobsen, Markus D; Sundstrup, Emil; Andersen, Lars L

    2016-01-01

    Background. Muscle strength is markedly reduced in stroke patients, which has negative implications for functional capacity and work ability. Different types of feedback during strength training exercises may alter neuromuscular activity and functional gains. Objective. To compare levels of muscle activity during conditions of blindfolding and intended high contraction speed with a normal condition of high-intensity knee flexions. Methods. Eighteen patients performed unilateral machine knee flexions with a 10-repetition maximum load. Surface electromyography (EMG) was recorded from the quadrics and hamstring muscles and normalized to maximal EMG (nEMG) of the nonparetic limb. Results. For the paretic leg, the speed condition showed higher values of muscle activity compared with the normal and blindfolded conditions for both biceps femoris and semitendinosus. Likewise, the speed condition showed higher co-contraction values compared with the normal and blindfolded conditions for the vastus lateralis. No differences were observed between exercise conditions for the nonparetic leg. Conclusion. Chronic stroke patients are capable of performing heavy resistance training with intended high speed of contraction. Focusing on speed during the concentric phase elicited higher levels of muscle activity of the hamstrings compared to normal and blindfolded conditions, which may have implications for regaining fast muscle strength in stroke survivors. PMID:27525118

  13. Lower Extremity Muscle Activation and Kinematics of Catchers When Throwing Using Various Squatting and Throwing Postures.

    PubMed

    Peng, Yi-Chien; Lo, Kuo-Cheng; Wang, Lin-Hwa

    2015-09-01

    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 pointsCommon 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

  14. Lower Extremity Muscle Activation and Kinematics of Catchers When Throwing Using Various Squatting and Throwing Postures.

    PubMed

    Peng, Yi-Chien; Lo, Kuo-Cheng; Wang, Lin-Hwa

    2015-09-01

    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 pointsCommon 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

  15. 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

  16. Quadratus femoris: An EMG investigation during walking and running.

    PubMed

    Semciw, Adam I; Freeman, Michael; Kunstler, Breanne E; Mendis, M Dilani; Pizzari, Tania

    2015-09-18

    Dysfunction of hip stabilizing muscles such as quadratus femoris (QF) is identified as a potential source of lower extremity injury during functional tasks like running. Despite these assumptions, there are currently no electromyography (EMG) data that establish the burst activity profile of QF during any functional task like walking or running. The objectives of this study were to characterize and compare the EMG activity profile of QF while walking and running (primary aim) and describe the direction specific action of QF (secondary aim). A bipolar fine-wire intramuscular electrode was inserted via ultrasound guidance into the QF of 10 healthy participants (4 females). Ensemble curves were generated from four walking and running trials, and normalized to maximum voluntary isometric contractions (MVICs). Paired t-tests compared the temporal and amplitude EMG variables. The relative activity of QF in the MVICs was calculated. The QF displayed moderate to high amplitude activity in the stance phase of walking and very high activity during stance in running. During swing, there was minimal QF activity recorded during walking and high amplitudes were present while running (run vs walk effect size=4.23, P<0.001). For the MVICs, external rotation and clam produced the greatest QF activity, with the hip in the anatomical position. This study provides an understanding of the activity demands placed on QF while walking and running. The high activity in late swing during running may signify a synergistic role with other posterior thigh muscles to control deceleration of the limb in preparation for stance.

  17. The lower body muscle activation of intermediate to experienced kayakers when navigating white water.

    PubMed

    Murtagh, Misha; Brooks, Darrell; Sinclair, Jonathan; Atkins, Stephen

    2016-11-01

    In white-water kayaking, the legs play a vital part in turning, stabilising and bracing actions. To date, there has been no reported information on neuromuscular activation of the legs in an authentic white-water environment. The aim of the current study was to identify lower body muscle activation, using 'in-boat' electromyography (EMG), whilst navigating a white-water run. Ten experienced male kayakers (age 31.5 ± 12.5 yr, intermediate to advanced experience) completed three successful runs of an international standard white-water course (grade 3 rapids), targeting right and left sides of the course, in a zigzag formation. Surface EMG (sEMG) outputs were generated, bilaterally, for the rectus femoris (RF), vastus lateralis, biceps femoris and gastrocnemius, expressed as a percentage of a dynamic maximal voluntary contraction (dMVC). Only RF showed significantly higher activation than any muscle on the left side of the body, and only on the left side of the course (P = .004; ETA(2) = 0.56). Other results showed no significant difference between muscle activation in the right and left legs during each run, nor when assessed at either the right or left side of the course (P > .05). These findings indicate that contralateral symmetry in lower limb muscle activation is evident during white-water kayaking. This symmetry may provide a stable base to allow more asymmetrical upper body and trunk movements to be fully optimised. Lower body symmetry development should be considered useful in targeted training programmes for white-water kayakers.

  18. Patterns of strain and activation in the thigh muscles of goats across gaits during level locomotion.

    PubMed

    Gillis, Gary B; Flynn, John P; McGuigan, Polly; Biewener, Andrew A

    2005-12-01

    Unlike homologous muscles in many vertebrates, which appear to function similarly during a particular mode of locomotion (e.g. red muscle in swimming fish, pectoralis muscle in flying birds, limb extensors in jumping and swimming frogs), a major knee extensor in mammalian quadrupeds, the vastus lateralis, appears to operate differently in different species studied to date. In rats, the vastus undergoes more stretching early in stance than shortening in later stance. In dogs, the reverse is true; more substantial shortening follows small amounts of initial stretching. And in horses, while the vastus strain trajectory is complex, it is characterized mainly by shortening during stance. In this study, we use sonomicrometry and electromyography to study the vastus lateralis and biceps femoris of goats, with three goals in mind: (1) to see how these muscles work in comparison to homologous muscles studied previously in other taxa; (2) to address how speed and gait impact muscle actions and (3) to test whether fascicles in different parts of the same muscle undergo similar length changes. Results indicate that the biceps femoris undergoes substantial shortening through much of stance, with higher strains in walking and trotting [32-33% resting length (L0)] than galloping (22% L0). These length changes occur with increasing biceps EMG intensities as animals increase speed from walking to galloping. The vastus undergoes a stretch-shorten cycle during stance. Stretching strains are higher during galloping (15% L0) than walking and trotting (9% L0). Shortening strains follow a reverse pattern and are greatest in walking (24% L0), intermediate in trotting (20% L0) and lowest during galloping (17% L0). As a result, the ratio of stretching to shortening increases from below 0.5 in walking and trotting to near 1.0 during galloping. This increasing ratio suggests that the vastus does relatively more positive work than energy absorption at the slower speeds compared with galloping

  19. [The expression of the sperm-specific lactate dehydrogenase gene Ldh-c in plateau pika (Ochotona curzoniae) cardiac muscle and its effect on the anaerobic glycolysis].

    PubMed

    Li, Xiao; Wei, Lian; Wang, Yang; Xu, Li-Na; Wei, Lin-Na; Wei, Deng-Bang

    2015-06-25

    The plateau pika (Ochotona curzoniae) has a strong adaptability to hypoxic plateau environment. We found that the sperm-specific lactate dehydrogenase (LDH-C4) gene Ldh-c expressed in plateau pika cardiac muscle. In order to shed light on the effect of LDH-C4 on the anaerobic glycolysis in plateau pika cardiac muscle, 20 pikas were randomly divided into the inhibitor group and the control group, and the sample size of each group was 10. The pikas of inhibitor group were injected with 1 mL 1 mol/L N-isopropyl oxamate, a specific LDH-C4 inhibitor, in biceps femoris muscle of hind legs, each leg with 500 μL. The pikas of control group were injected with the same volume of normal saline (0.9% NaCl). The mRNA and protein expression levels of Ldh-c gene in plateau pika cardiac muscle were determined by real-time PCR and Western blot. The activities of LDH, and the contents of lactate (LD) and ATP in cardiac muscle were compared between the inhibitor group and the control group. The results showed that 1) the expression levels of Ldh-c mRNA and protein were 0.47 ± 0.06 and 0.68 ± 0.08, respectively; 2) 30 min after injection of 1 mL 1 mol/L N-isopropyl oxamate in biceps femoris muscle, the concentration of N-isopropyl oxamate in blood was 0.08 mmol/L; 3) in cardiac muscle of the inhibitor group and the control group, the LDH activities were (6.18 ± 0.48) U/mg and (9.08 ± 0.58) U/mg, the contents of LD were (0.21 ± 0.03) mmol/g and (0.26 ± 0.04) mmol/g, and the contents of ATP were (4.40 ± 0.69) nmol/mg and (6.18 ± 0.73) nmol/mg (P < 0.01); 5) the inhibition rates of N-isopropyl oxamate to LDH, LD and ATP were 31.98%, 20.90% and 28.70%, respectively. The results suggest that Ldh-c expresses in cardiac muscle of plateau pika, and the pika cardiac muscle may get at least 28% ATP for its activities by LDH-C4 catalyzed anaerobic glycolysis, which reduces the dependence on oxygen and enhances the adaptation to the hypoxic environments.

  20. Electromyography of selected lower-limb muscles fatigued by exercise at the intensity of soccer match-play.

    PubMed

    Rahnama, Nader; Lees, Adrian; Reilly, Thomas

    2006-06-01

    Surface electromyography has been useful in comparing muscular activity among different sports movements and it is a valuable technique for evaluating muscle activation, co-ordination and fatigue. Since these important variables have not been investigated during the full game in soccer, the present study aimed to investigate the activity of major muscles of the lower extremity during a soccer-simulation fatiguing protocol. Ten amateur soccer players (age 21.40+/-3.13 years; height 1.77+/-0.06 m; mass 74.55+/-8.5 kg) were tested. The exercise protocol, performed on a programmable motorised treadmill, consisted of the different intensities observed during soccer match-play (walking, jogging, running, sprinting). Electromyographic activity was recorded from the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA) and gastrocnemius (GC) muscles before exercise, at half-time and immediately after the 90-min exercise protocol. The EMG data were analysed using custom-written software to compute the root mean square (RMS) value over ten gait cycles. With regard to RF, BF and TA, a significant main effect (P< 0.05) was found for condition (pre-game, half-time and post-game), speed (6, 12, 15 and 21 km h(-1)) (P<0.05) and interaction between condition and speed (P< 0.05). For GC, a significant effect was not found for condition or interaction between condition and speed, but a significant main effect (P< 0.001) was found for speed, with the RMS value increasing continually with increasing speed from 6 to 2 1km h(-1). The results indicated that after a simulation of the exercise intensity of soccer-play the EMG activity in major lower-limb muscles was less than before. This decrease indicated that prolonged intermittent exercise had an effect on muscle activity even when work-rate was sustained.

  1. Hamstring muscle forces prior to and immediately following an acute sprinting-related muscle strain injury.

    PubMed

    Schache, Anthony G; Kim, Hyung-Joo; Morgan, David L; Pandy, Marcus G

    2010-05-01

    A thorough understanding of the biomechanics of the hamstrings during sprinting is required to optimise injury rehabilitation and prevention strategies. The main aims of this study were to compare hamstrings load across different modes of locomotion as well as before and after an acute sprinting-related muscle strain injury. Bilateral kinematic and ground reaction force data were captured from a single subject whilst walking, jogging and sprinting prior to and immediately following a significant injury involving the right semitendinosis and biceps femoris long head muscles. Experimental data were input into a three-dimensional musculoskeletal model of the body and used, together with optimisation theory, to determine lower-limb muscle forces for each locomotor task. Hamstrings load was found to be greatest during terminal swing for sprinting. The hamstrings contributed the majority of the terminal swing hip extension and knee flexion torques, whilst gluteus maximus contributed most of the stance phase hip extension torque. Gastrocnemius contributed little to the terminal swing knee flexion torque. Peak hamstrings force was also substantially greater during terminal swing compared to stance for sprinting, but not for walking and jogging. Immediately following the muscle strain injury, the hamstrings demonstrated an intolerance to perform an eccentric-type contraction. Whilst peak hamstrings force during terminal swing did not decrease post-injury, both peak hamstrings length and negative work during terminal swing were considerably reduced. These results lend support to the paradigm that the hamstrings are most susceptible to muscle strain injury during the terminal swing phase of sprinting when they are contracting eccentrically.

  2. Influence of type of muscles on nutritional value of foal meat.

    PubMed

    Lorenzo, José M; Pateiro, Mirian

    2013-03-01

    The effect of type of muscle on nutritional characteristic (fatty acid profile, amino acid content, cholesterol and major and minor mineral) of foal meat was investigated. Six muscles: longissimus dorsi (LD), semimembranosus (SM), semitendinosus (ST), biceps femoris (BF), triceps brachii (TB) and psoas major & minor (PM) from twelve foals slaughtered at 15 months from an extensive production system in freedom regimen were extracted for this study. Horse meat is characterized by low fat, low cholesterol content, rich in iron and in vitamin B. Statistical analysis showed that the cholesterol content did not show significant differences (P>0.05) among muscle with mean value range between 0.62 and 0.57 mg/100g. Most fatty acid presented significant differences (P<0.05) with respect to the type of muscle. The obtained results showed that except for the polyunsaturated linoleic acid, the highest contents of fatty acids were found in the hindquarter muscles. Regarding amino acid profile, significant differences (P<0.05) were observed among muscles and our results indicated that, 100g of foal meat covered from 80.6 to 86.7% for the daily requirement for an adult man weighing 70 kg for essential amino acids for ST and LD muscles, respectively. Statistical analysis showed significant differences (P=0.050) for the EAA (essential amino acids) index, which was highest for TB muscle, followed by BF and SM muscles, while the lowest values were reported by ST muscle. Finally, foal meat seems to be a very good nutritional source of major and minor minerals. The higher nutritional value of foal meat will be of great importance in the promotion of this meat.

  3. Muscle fiber conduction velocity in different gait phases of early and late-stage diabetic neuropathy.

    PubMed

    Suda, Eneida Yuri; Gomes, Aline A; Butugan, Marco Kenji; Sacco, Isabel C N

    2016-10-01

    We investigated the muscle fiber conduction velocity (MFCV) during gait phases of the lower limb muscles in individuals with various degrees of diabetic peripheral neuropathy (DPN). Forty-five patients were classified into severity degrees of DPN by a fuzzy model. The stages were absent (n=11), mild (n=14), moderate (n=11) and severe (n=9), with 10 matched healthy controls. While walking, all subjects had their sEMG (4 linear electrode arrays) recorded for tibialis anterior (TA), gastrocnemius medialis (GM), vastus lateralis (VL) and biceps femoris (BF). MFCV was calculated using a maximum likelihood algorithm with 30ms standard deviation Gaussian windows. In general, individuals in the earlier stages of DPN showed lower MFCV of TA, GM and BF, whilst individuals with severe DPN presented higher MFCV of the same muscles. We observed that mild patients already showed lower MFCV of TA at early stance and swing, and lower MFCV of BF at swing. All diabetic groups showed a markedly reduction in MFCV of VL, irrespective of DPN. Severe patients presented higher MFCV mainly in distal muscles, TA at early and swing phases and GM at propulsion and midstance. The absent group already showed MFCV of VL and GM reductions at the propulsion phase and of VL at early stance. Although MFCV changes were not as progressive as the DPN was, we clearly distinguished diabetic patients from controls, and severe patients from all others.

  4. Minimal seasonal alterations in the skeletal muscle of captive brown bears.

    PubMed

    Hershey, John D; Robbins, Charles T; Nelson, O Lynne; Lin, David C

    2008-01-01

    Abstract Previous studies on wild black bears (Ursus americanus) have shown that skeletal muscle morphology, composition, and overall force-generating capacity do not differ drastically between seasons despite prolonged inactivity during hibernation. However, the amount and characteristics of the seasonal variations were not consistent in these studies. The goals of this study were to compare the amount of muscle atrophy in captive brown bears (Ursus arctos) with that observed in wild black bears and measure seasonal differences in twitch characteristics. Samples from the biceps femoris muscle were collected during the summer and winter. Protein concentration, fiber-type composition, and fiber cross-sectional area were measured along with twitch characteristics. The protein concentration of the winter samples was 8.2% lower than that of the summer samples; fiber cross-sectional area and the relative proportion of fast and slow fibers remained unchanged between seasons. Myosin heavy chain isoforms I, IIa, and IIx were identified by immunoblotting and electrophoresis, and the proportions did not change between seasons. The half-rise time in the twitch contractions increased in winter relative to summer samples, which is unexpected under disuse conditions. These results agreed with a study that showed minimal skeletal muscle atrophy between seasons in wild black bears. PMID:18173360

  5. Individual Muscle use in Hamstring Exercises by Soccer Players Assessed using Functional MRI.

    PubMed

    Fernandez-Gonzalo, R; Tesch, P A; Linnehan, R M; Kreider, R B; Di Salvo, V; Suarez-Arrones, L; Alomar, X; Mendez-Villanueva, A; Rodas, G

    2016-06-01

    This study used functional magnetic resonance imaging (fMRI) to compare individual muscle use in exercises aimed at preventing hamstring injuries. Thirty-six professional soccer players were randomized into 4 groups, each performing either Nordic hamstring, flywheel leg curl, Russian belt or conic-pulley exercise. MRIs were performed before and immediately after a bout of 4 sets of 8 repetitions. Pre-post exercise differences in contrast shift (T2) were analyzed for the long (BFLh) and short head (BFSh) of biceps femoris, semitendinosus (ST), semimembranosus (SM) and gracilis (GR) muscles. Flywheel leg curl increased (P<0.001) T2 of GR (95%), ST (65%), BFSh (51%) and BFLh (14%). After the Nordic hamstring, GR (39%), ST (16%) and BFSh (14%) showed increased T2 (P<0.001). Russian belt and conic-pulley exercise produced subtle (P<0.02) T2 increases of ST (9 and 6%, respectively) and BFLh (7 and 6%, respectively). Russian belt increased T2 of SM (7%). Among exercises examined, flywheel leg curl showed the most substantial hamstring and GR muscle use. However, no single exercise executed was able to increase T2 of all hamstring and synergist muscles analyzed. It is therefore suggested that multiple exercises must be carried out to bring in, and fully activate all knee flexors and hip extensors. PMID:27116347

  6. Muscle fiber conduction velocity in different gait phases of early and late-stage diabetic neuropathy.

    PubMed

    Suda, Eneida Yuri; Gomes, Aline A; Butugan, Marco Kenji; Sacco, Isabel C N

    2016-10-01

    We investigated the muscle fiber conduction velocity (MFCV) during gait phases of the lower limb muscles in individuals with various degrees of diabetic peripheral neuropathy (DPN). Forty-five patients were classified into severity degrees of DPN by a fuzzy model. The stages were absent (n=11), mild (n=14), moderate (n=11) and severe (n=9), with 10 matched healthy controls. While walking, all subjects had their sEMG (4 linear electrode arrays) recorded for tibialis anterior (TA), gastrocnemius medialis (GM), vastus lateralis (VL) and biceps femoris (BF). MFCV was calculated using a maximum likelihood algorithm with 30ms standard deviation Gaussian windows. In general, individuals in the earlier stages of DPN showed lower MFCV of TA, GM and BF, whilst individuals with severe DPN presented higher MFCV of the same muscles. We observed that mild patients already showed lower MFCV of TA at early stance and swing, and lower MFCV of BF at swing. All diabetic groups showed a markedly reduction in MFCV of VL, irrespective of DPN. Severe patients presented higher MFCV mainly in distal muscles, TA at early and swing phases and GM at propulsion and midstance. The absent group already showed MFCV of VL and GM reductions at the propulsion phase and of VL at early stance. Although MFCV changes were not as progressive as the DPN was, we clearly distinguished diabetic patients from controls, and severe patients from all others. PMID:27567140

  7. Metabolic demand and muscle activation during different forms of bodyweight supported locomotion in men with incomplete SCI.

    PubMed

    Fenuta, Alyssa M; Hicks, Audrey L

    2014-01-01

    Body weight supported locomotor training uses neuroplasticity principles to improve recovery following a spinal cord injury (SCI). Steady state locomotion using the same body weight support (BWS) percent was compared in 7 males (42.6 ± 4.29 years) with incomplete SCI and matched (gender, age) noninjured controls (42.7 ± 5.4 years) using the Lokomat, Manual Treadmill, and ZeroG. The VO2000, Polar Heart Rate (HR) Monitor, and lower limb electromyography (EMG) electrodes were worn during the 2-minute sessions. Oxygen uptake (VO2) and HR were expressed as percentage of peak values obtained using progressive arm ergometry; VO2 was also expressed relative to resting metabolic equivalents (METS). Filtered EMG signals from tibialis anterior (TA), rectus femoris (RF), biceps femoris (BF), and medial gastrocnemius (MG) were normalized to ZeroG stepping. The Lokomat required 30% of VO2 peak (2METS) compared to ~54% (3METS) for Manual Treadmill and ZeroG sessions. HR was 67% of peak during Lokomat sessions compared to ~83% for Manual Treadmill and ZeroG. Muscle activation was higher in treadmill conditions compared to the ZeroG primarily due to increased BF activity. At the same level of BWS, locomotion using the Manual Treadmill or the ZeroG is more aerobically demanding than the Lokomat. Treadmill modalities encourage greater hip extensor activation compared to overground locomotion.

  8. The influence of visual information on multi-muscle control during quiet stance: a spectral analysis approach.

    PubMed

    Danna-Dos-Santos, Alessander; Degani, Adriana M; Boonstra, Tjeerd W; Mochizuki, Luis; Harney, Allison M; Schmeckpeper, Megan M; Tabor, Lori C; Leonard, Charles T

    2015-02-01

    Standing upright requires the coordination of neural drives to a large set of muscles involved in controlling human bipedal stance (i.e., postural muscles). The coordination may deteriorate in situations where standing is performed under more challenging circumstances, such as standing on a smaller base of support or not having adequate visual information. The present study investigates the role of common neural inputs in the organization of multi-muscle synergies and the effects of visual input disruption to this mechanism of control. We analyzed the strength and distribution of correlated neural inputs (measured by intermuscular coherence) to six postural muscles previously recognized as components of synergistic groups involved in the maintenance of the body's vertical positioning. Two experimental conditions were studied: quiet bipedal stance performed with opened eyes (OEs) and closed eyes (CEs). Nine participants stood quietly for 30 s while the activity of the soleus, biceps femoris, lumbar erector spinae, tibialis anterior, rectus femoris, and rectus abdominis muscles were recorded using surface electrodes. Intermuscular (EMG-EMG) coherence was estimated for 12 muscle pairs formed by these muscles, including pairs formed solely by either posterior, anterior, or mixed (one posterior and one anterior) muscles. Intermuscular coherence was only found to be significant for muscle pairs formed solely by either posterior or anterior muscles, and no significant coherence was found for mixed muscle pairs. Significant intermuscular coherence was only found within a distinct frequency interval bounded between 1 and 10 Hz when visual input was available (OEs trials). The strength of correlated neural inputs was similar across muscle pairs located in different joints but executing a similar function (pushing body either backward or forward) suggesting that synergistic postural groups are likely formed based on their functional role instead of their anatomical location

  9. Changes in Porcine Muscle Water Characteristics during Growth—An in Vitro Low-Field NMR Relaxation Study

    NASA Astrophysics Data System (ADS)

    Bertram, Hanne Christine; Rasmussen, Marianne; Busk, Hans; Oksbjerg, Niels; Karlsson, Anders Hans; Andersen, Henrik Jørgen

    2002-08-01

    This study investigates the effects of developmental stage and muscle type on the mobility and distribution of water within skeletal muscles, using low-field 1H-NMR transverse relaxation measurements in vitro on four different porcine muscles ( M. longissimus dorsi, M. semitendinosus, M. biceps femoris, M. vastus intermedius) from a total of 48 pigs slaughtered at various weight classes between 25 kg and 150 kg. Principal component analysis (PCA) revealed effects of both slaughter weight and muscle type on the transverse relaxation decay. Independent of developmental stage and muscle type, distributed exponential analysis of the NMR T 2 relaxation data imparted the existence of three distinct water populations, T 2b, T 21, and T 22, with relaxation times of approximately 1-10, 45-120, and 200-500 ms, respectively. The most profound change during muscle growth was a shift toward faster relaxation in the intermediate time constant, T 21. It decreased by approx. 24% in all four muscle types during the period from 25 to 150 kg live weight. Determination of dry matter, fat, and protein content in the muscles showed that the changes in relaxation time of the intermediate time constant, T 21, during growth should be ascribed mainly to a change in protein content, as the protein content explained 77% of the variation in the T 21 time constant. Partial least squares (PLS) regression revealed validated correlations in the region of 0.58 to 0.77 between NMR transverse relaxation data and muscle development for all the four muscle types, which indicates that NMR relaxation measurements may be used in the prediction of muscle developmental stage.

  10. Leg and trunk muscle coordination and postural sway during increasingly difficult standing balance tasks in young and older adults.

    PubMed

    Donath, Lars; Kurz, Eduard; Roth, Ralf; Zahner, Lukas; Faude, Oliver

    2016-09-01

    Ageing impairs body balance and increases older adults' fall risk. Balance training can improve intrinsic fall risk factors. However, age comparisons of muscle activity responses during balance tasks are lacking. This study investigated relative muscle activity, muscle coordination and postural sway during various recommended static balance training tasks. Muscle activity (%MVC), amplitude ratios (AR) and co-activity (CAI) were determined during standing tasks for 30s (1: double limb stance on a foam surface, eyes open; 2: double limb stance on firm ground, eyes closed; 3: double limb stance, feet in step position on a foam surface, eyes open; 4: double limb stance, feet in step position on firm ground, eyes closed; 5: single limb stance on firm ground, eyes open) in 20 healthy young adults (24±2 y) and 20 older adults (73±6 y). Surface electromyography (SEMG) was applied (SENIAM guidelines) to ankle (tibialis anterior, soleus, medial gastrocnemius, peroneus longus) and thigh (vastus lateralis, vastus medialis, biceps femoris, semitendinosus) muscles (non-dominant leg). Electrodes over trunk (multifidus and internal oblique) muscles were applied bilaterally. Two- to six-fold higher levels of relative muscle activity were found in older adults for ankle (0.0002muscles. Co-activation was elevated in young adults for the trunk (0.001muscle coordination patterns during all stance conditions at the ankle (0.06<ηp(2)<0.28) and the trunk (0.14<ηp(2)<0.23). Older adults had higher electrophysiological costs for all stance conditions. Muscle coordination showed inverse activity patterns at the ankle and trunk. Optimal balance and strength training programs should take into account age-specific alterations in muscle activity.

  11. Accessory muscle activation during the superimposed burst technique.

    PubMed

    Roberts, Devin; Kuenze, Christopher; Saliba, Susan; Hart, Joseph M

    2012-08-01

    Quadriceps muscle activation is assessed using the superimposed burst technique. This technique involves percutaneous muscle stimulation superimposed during maximal isometric volitional knee extension. It is unknown whether accessory muscle activation during maximal knee extension influences estimates of quadriceps muscle activation. Our aim was to compare accessory muscle activation while performing the superimposed burst technique using investigator delivered verbal instruction to constrain the system (CS) and a participant preferred (PP) technique. Twenty five healthy, active individuals (13M/12F, age=23.8 ± 3.35, height=72.73 ± 14.51 cm, and weight=175.29 ± 9.59 kg) were recruited for this study. All participants performed superimposed burst testing with (CS) and without (PP) verbal instruction to encourage isolated quadriceps activation during maximal isometric knee extension. The main outcome variables measured were knee extension torque, quadriceps central activation ratio and mean EMG of vastus lateralis, biceps femoris, and lumbar paraspinal muscles. There were significant differences in knee extension torque (CS=2.87 ± 0.93 Nm/kg, PP=3.40 ± 1.12 Nm/kg, p<0.001), superimposed burst torque (CS=3.40 ±0.98 Nm/kg, PP=3.75 ± 1.11 Nm/kg, p=0.002) and quadriceps CAR (CS=84.1 ± 12.0%, PP=90.2 ± 9.9%, p<0.001) between the techniques. There was also a significant difference in lumbar paraspinal EMG (CS=6.40 ± 8.52%, PP=11.86 ± 14.89%, p=0.043) between the techniques however vastus lateralis EMG was not significantly different. Patient instruction via verbal instruction to constrain proximal structures may help patient minimize confounders to knee extension torque generation while maximizing quadriceps activation.

  12. Composite inflation confronts BICEP2 and PLANCK

    NASA Astrophysics Data System (ADS)

    Karwan, Khamphee; Channuie, Phongpichit

    2014-06-01

    We examine observational constraints on single-field inflation in which the inflaton is a composite field stemming from a four-dimensional strongly interacting field theory. We confront the predictions with the Planck and very recent BICEP2 data. In the large non-minimal coupling regions, we discover for the minimal composite inflationary model that the predictions lie well inside the joint 68% CL for the Planck data, but is in tension with the recent BICEP2 observations. In the case of the glueball inflationary model, the predictions satisfy the Planck results. However, this model can produce a large tensor-to-scalar ratio consistent with the recent BICEP2 observations if the number of e-foldings is slightly smaller than the range commonly used. For a super Yang-Mills paradigm, we discover that the predictions satisfy the Planck data, and surprisingly a large tensor-to-scalar ratio consistent with the BICEP2 results can also be produced for an acceptable range of the number of e-foldings and of the confining scale. In the small non-minimal coupling regions, all of the models can satisfy the BICEP2 results. However, the predictions of the glueball and superglueball inflationary models cannot satisfy the observational bound on the amplitude of the curvature perturbation launched by Planck, and the techni-inflaton self-coupling in the minimal composite inflationary model is constrained to be extremely small.

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

    PubMed

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

    2016-10-01

    The present study aimed to compare muscle coordination strategies of the upper and lower limb muscles between beginners and elite breaststroke swimmers. Surface electromyography (EMG) of eight muscles was recorded in 16 swimmers (8 elite, 8 beginners) during a 25 m swimming breaststroke at 100% of maximal effort. A decomposition algorithm was used to identify the muscle synergies that represent the temporal and spatial organisation of muscle coordination. Between-groups indices of similarity and lag times were calculated. Individual muscle patterns were moderately to highly similar between groups (between-group indices range: 0.61 to 0.84). Significant differences were found in terms of lag time for pectoralis major (P < 0.05), biceps brachii, rectus femoris and tibialis anterior (P < 0.01), indicating an earlier activation for these muscles in beginners compared to elites (range: -13.2 to -3.8% of the swimming cycle). Three muscle synergies were identified for both beginners and elites. Although their composition was similar between populations, the third synergy exhibited a high within-group variability. Moderate to high indices of similarity were found for the shape of synergy activation coefficients (range: 0.63 to 0.88) but there was a significant backward shift (-8.4% of the swimming cycle) in synergy #2 for beginners compared to elites. This time shift suggested differences in the global arm-to-leg coordination. These results indicate that the synergistic organisation of muscle coordination during breaststroke swimming is not profoundly affected by expertise. However, specific timing adjustments were observed between lower and upper limbs. PMID:26878097

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

    PubMed

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

    2016-10-01

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

  15. Raman spectroscopic study of acute oxidative stress induced changes in mice skeletal muscles

    NASA Astrophysics Data System (ADS)

    Sriramoju, Vidyasagar; Alimova, Alexandra; Chakraverty, Rahul; Katz, A.; Gayen, S. K.; Larsson, L.; Savage, H. E.; Alfano, R. R.

    2008-02-01

    The oxidative stress due to free radicals is implicated in the pathogenesis of tissue damage in diseases such as muscular dystrophy, Alzheimer dementia, diabetes mellitus, and mitochrondrial myopathies. In this study, the acute oxidative stress induced changes in nicotinamide adenine dinucleotides in mouse skeletal muscles are studied in vitro using Raman spectroscopy. Mammalian skeletal muscles are rich in nicotinamide adenine dinucleotides in both reduced (NADH) and oxidized (NAD) states, as they are sites of aerobic and anaerobic respiration. The relative levels of NAD and NADH are altered in certain physiological and pathological conditions of skeletal muscles. In this study, near infrared Raman spectroscopy is used to identify the molecular fingerprints of NAD and NADH in five-week-old mice biceps femoris muscles. A Raman vibrational mode of NADH is identified in fresh skeletal muscle samples suspended in buffered normal saline. In the same samples, when treated with 1% H IIO II for 5 minutes and 15 minutes, the Raman spectrum shows molecular fingerprints specific to NAD and the disappearance of NADH vibrational bands. The NAD bands after 15 minutes were more intense than after 5 minutes. Since NADH fluoresces and NAD does not, fluorescence spectroscopy is used to confirm the results of the Raman measurements. Fluorescence spectra exhibit an emission peak at 460 nm, corresponding to NADH emission wavelength in fresh muscle samples; while the H IIO II treated muscle samples do not exhibit NADH fluorescence. Raman spectroscopy may be used to develop a minimally invasive, in vivo optical biopsy method to measure the relative NAD and NADH levels in muscle tissues. This may help to detect diseases of muscle, including mitochondrial myopathies and muscular dystrophies.

  16. Chemical composition and amino acid profiles of goose muscles from native Polish breeds.

    PubMed

    Okruszek, A; Woloszyn, J; Haraf, G; Orkusz, A; Werenska, M

    2013-04-01

    The aim of the study was to compare the chemical and amino acid composition of breast (pectoralis major) and thigh (biceps femoris) muscles in 17-wk-old geese from 2 Polish conservative flocks: Rypińska (Ry, n = 20) and Garbonosa (Ga, n = 20). The geese were fed ad libitum during the experimental period on the same complete feed. Genotypes affected the moisture and fat content of breast and thigh meat. The Ga geese were characterized by higher moisture as well as lower fat lipid content compared with the Ry breast and thigh muscles. The amino acid proportions of meat proteins depended on the goose flock and type of muscles, where significant differences were found. The proteins of Ga breast muscles contained more glutamic acid, glycine, lysine, tryptophan, histidine, and methionine, and less aspartic acid, proline, serine, leucine, valine, phenyloalanine, tyrosine, and threonine than the Ry geese (P ≤ 0.05). The proteins of Ry thigh muscles were characterized by higher content of proline, serine, and essential amino acids (without lysine and methionine) and lower glutamic and asparagine acid, alanine, and glycine compared with the Ga flock. According to the Food and Agriculture Organization of the United Nations/World Health Organization (1991) standard, tryptophan was the amino acid limiting the nutritional value of meat proteins of Ry breast muscles (amino acid score for tryptophan = 90%). Except for tryptophan, the meat proteins of the investigated raw materials contained more essential amino acids than the standard. The total content of essential amino acids for all investigated muscles was also higher (52.51 to 55.54%) than the standard (33.90%). It is evident that muscle protein from both flocks of geese have been characterized by high nutritional value. The values of the essential amino acid index of breast muscle proteins were similar in both flocks.

  17. Effects of a 10-week resistance exercise program on soccer kick biomechanics and muscle strength.

    PubMed

    Manolopoulos, Evaggelos; Katis, Athanasios; Manolopoulos, Konstantinos; Kalapotharakos, Vasileios; Kellis, Eleftherios

    2013-12-01

    The purpose of the study was to examine the effects of a resistance exercise program on soccer kick biomechanics. Twenty male amateur soccer players were divided in the experimental group (EG) and the control group (CG), each consisting of 10 players. The EG followed a 10-week resistance exercise program mainly for the lower limb muscles. Maximal instep kick kinematics, electromyography, and ground reaction forces (GRFs) as well as maximum isometric leg strength were recorded before and after training. A 2-way analysis of variance showed significantly higher ball speed values only for the EG (26.14 ± 1.17 m·s vs. 27.59 ± 1.49 m·s before and after training, respectively), whereas no significant differences were observed for the CG. The EG showed a decline in joint angular velocities and an increase in biceps femoris electromyography of the swinging leg during the backswing phase followed by a significant increase in segmental and joint velocities and muscle activation of the same leg during the forward swing phase (p < 0.05). The EG also showed significantly higher vertical GRFs and rectus femoris and gastrocnemius activation of the support leg (p < 0.05). Similarly, maximum and explosive isometric force significantly increased after training only for the EG (p < 0.05). These results suggest that increases in soccer kicking performance after a 10-week resistance training program were accompanied by increases in maximum strength and an altered soccer kick movement pattern, characterized by a more explosive backward-forward swinging movement and higher muscle activation during the final kicking phase.

  18. Sensitivity of subject-specific models to Hill muscle-tendon model parameters in simulations of gait.

    PubMed

    Carbone, V; van der Krogt, M M; Koopman, H F J M; Verdonschot, N

    2016-06-14

    Subject-specific musculoskeletal (MS) models of the lower extremity are essential for applications such as predicting the effects of orthopedic surgery. We performed an extensive sensitivity analysis to assess the effects of potential errors in Hill muscle-tendon (MT) model parameters for each of the 56 MT parts contained in a state-of-the-art MS model. We used two metrics, namely a Local Sensitivity Index (LSI) and an Overall Sensitivity Index (OSI), to distinguish the effect of the perturbation on the predicted force produced by the perturbed MT parts and by all the remaining MT parts, respectively, during a simulated gait cycle. Results indicated that sensitivity of the model depended on the specific role of each MT part during gait, and not merely on its size and length. Tendon slack length was the most sensitive parameter, followed by maximal isometric muscle force and optimal muscle fiber length, while nominal pennation angle showed very low sensitivity. The highest sensitivity values were found for the MT parts that act as prime movers of gait (Soleus: average OSI=5.27%, Rectus Femoris: average OSI=4.47%, Gastrocnemius: average OSI=3.77%, Vastus Lateralis: average OSI=1.36%, Biceps Femoris Caput Longum: average OSI=1.06%) and hip stabilizers (Gluteus Medius: average OSI=3.10%, Obturator Internus: average OSI=1.96%, Gluteus Minimus: average OSI=1.40%, Piriformis: average OSI=0.98%), followed by the Peroneal muscles (average OSI=2.20%) and Tibialis Anterior (average OSI=1.78%) some of which were not included in previous sensitivity studies. Finally, the proposed priority list provides quantitative information to indicate which MT parts and which MT parameters should be estimated most accurately to create detailed and reliable subject-specific MS models. PMID:27131851

  19. Comparison of electromyography fatigue threshold in lower limb muscles in trained cyclists and untrained non-cyclists.

    PubMed

    Smirmaul, B P C; Dantas, J L; Fontes, E B; Altimari, L R; Okano, A H; Moraes, A C

    2010-01-01

    The purpose of this study was to identify and compare the Electromyographic Fatigue Threshold (EMG(FT)) determined in the Vastus Lateralis (VL), Rectus Femoris (RF), Biceps Femoris (BF), Semitendinosus (ST) and Tibialis Anterior (TA) during stationary cycling in trained cyclists and non-cyclists. Using a cycle ergometer, 13 cyclists (28.4 +/- 6.9 years; 70.3 +/- 13 kg; 176.1 +/- 8.5 cm) and 11 non-cyclists (25.8 +/- 4 years; 73 +/- 9.1 kg; 175 +/- 6.4 cm), performed a maximum incremental test (ITmax) (90 rpm) to determine the (EMG(FT)). Maximal power output (W(PEAK)) reached by cyclists was higher than for non-cyclists (372.6 W and 248.9 W respectively) (P < 0.01). For the five muscles analyzed in cyclists, EMG(FT) occurred at 85.7% of cases in the VL, 92.9% in RE 78.6% in BE 78.6% in ST and 50% in TA, while in the non-cyclists group, this occurrence was 100% to muscle VL, 100% to RF, 92.6% to BF, 78.6% to ST, and 78.6% to TA. Analyzing the percentage corresponding to the power at EMG(FT) in relation to W(PEAK) reached, no differences between groups were observed for RF, BF and ST, however VL and TA, as well as the mean from all muscles were lower for cyclists than non-cyclists (P < 0.05). The present results showed that EMG(FT) is more easily identified in RF and VL muscles for both groups, and it may be an interesting method to evaluate the adaptive responses from aerobic and anaerobic metabolisms during cycling training programs.

  20. Facilitation of corticospinal excitability in the tibialis anterior muscle during robot-assisted passive stepping in humans.

    PubMed

    Kamibayashi, Kiyotaka; Nakajima, Tsuyoshi; Takahashi, Makoto; Akai, Masami; Nakazawa, Kimitaka

    2009-07-01

    Although phasic modulation of the corticospinal tract excitability to the lower limb muscles has been observed during normal walking, it is unclear to what extent afferent information induced by walking is related to the modulation. The purpose of this study was to test the corticospinal excitability to the lower limb muscles by using transcranial magnetic stimulation (TMS) and transcranial electrical stimulation of the motor cortex while 13 healthy subjects passively stepped in a robotic driven-gait orthosis. Specifically, to investigate the effect of load-related afferent inputs on the corticospinal excitability during passive stepping, motor evoked potentials (MEPs) in response to the stimulation were compared between two passive stepping conditions: 40% body weight unloading on a treadmill (ground stepping) and 100% body weight unloading in the air (air stepping). In the rectus femoris, biceps femoris and tibialis anterior (TA) muscles, electromyographic activity was not observed throughout the step cycle in either stepping condition. However, the TMS-evoked MEPs of the TA muscle at the early- and late-swing phases as well as at the early-stance phase during ground stepping were significantly larger than those observed during air stepping. The modulation pattern of the transcranial electrical stimulation-evoked MEPs was similar to that of the TMS-evoked MEPs. These results suggest that corticospinal excitability to the TA is facilitated by load-related afferent inputs. Thus, these results might be consistent with the notion that load-related afferent inputs play a significant role during locomotor training for gait disorders.

  1. COMPARISON OF TRUNK AND LOWER EXTREMITY MUSCLE ACTIVITY AMONG FOUR STATIONARY EQUIPMENT DEVICES: UPRIGHT BIKE, RECUMBENT BIKE, TREADMILL, AND ELLIPTIGO®

    PubMed Central

    Baker, Ryan; Gibson, Chris; Kearney, Andrew; Busemeyer, Tommy

    2016-01-01

    Background Stationary equipment devices are often used to improve fitness. The ElliptiGO® was recently developed that blends the elements of an elliptical trainer and bicycle, allowing reciprocal lower limb pedaling in an upright position. However, it is unknown whether the muscle activity used for the ElliptiGO® is similar to walking or cycling. To date, there is no information comparing muscle activity for exercise on the treadmill, stationary upright and recumbent bikes, and the ElliptiGO®. Purpose/Hypothesis The purpose of this study was to assess trunk and lower extremity muscle activity among treadmill walking, cycling (recumbent and upright) and the ElliptiGO® cycling. It was hypothesized that the ElliptiGO® and treadmill would elicit similar electromyographic muscle activity responses compared to the stationary bike and recumbent bike during an exercise session. Study Design Cohort, repeated measures Methods Twelve recreationally active volunteers participated in the study and were assigned a random order of exercise for each of the four devices (ElliptiGO®, stationary upright cycle ergometer, recumbent ergometer, and a treadmill). Two-dimensional video was used to monitor the start and stop of exercise and surface electromyography (SEMG) were used to assess muscle activity during two minutes of cycling or treadmill walking at 40-50% heart rate reserve (HRR). Eight muscles on the dominant limb were used for analysis: gluteus maximus (Gmax), gluteus medius (Gmed), biceps femoris (BF), lateral head of the gastrocnemius (LG), tibialis anterior (TA), rectus femoris (RF). Two trunk muscles were assessed on the same side; lumbar erector spinae at L3-4 level (LES) and rectus abdominus (RA). Maximal voluntary isometric contractions (MVIC) were determined for each muscle and SEMG data were expressed as %MVIC in order to normalize outputs. Results The %MVIC for RF during ElliptiGO® cycling was higher than recumbent cycling. The LG muscle activity was highest

  2. Muscle activation pattern and onset times during a semi-orthostatic, unilateral closed-kinetic hip extension exercise in adolescent males.

    PubMed

    Cochrane, Darryl J; Harnett, Michael C

    2015-07-01

    The hip extensors are an important muscle group for sporting and functional movements, but assessing this muscle group for musculoskeletal dysfunction and strength testing has been performed in adult males and females as a prone, open-chain exercise, which provides little posture specificity for locomotive activities. Given the importance of closed-kinetic chain exercises for strength and rehabilitation requirements, there is an obvious need to assess hip extension but little is known about executing a closed-kinetic chain hip extension exercise for adolescents. Therefore, the aim of this study was to ascertain hip extensor muscle activation pattern and force production using a semi-orthostatic position while performing a unilateral closed-kinetic hip extension exercise. Fourteen young healthy adolescent male participants performed three maximal repetitions of closed-kinetic chain left and right hip extension on a glute machine. Electromyography (EMG) from left and right rectus femoris (RF), gluteus maximus (GM), and biceps femoris (BF) was recorded and RF, GM, and BF EMG mean amplitude, EMG area and onset times were analysed. There was no significant difference in EMG mean amplitude and EMG area between RF, GM, and BF but the right hip showed a significantly higher EMG (p < 0.05) than the left hip. The relative onset difference between GM and BF was similar in both hips, suggesting that there was no dominant muscle firing order. The closed-kinetic chain hip extension could be advantageous when assessing neuromuscular function and training muscle strength because the semi-orthostatic position of hip extension exercise provides a posture similar to functional activities. PMID:25613523

  3. Muscle activation pattern and onset times during a semi-orthostatic, unilateral closed-kinetic hip extension exercise in adolescent males.

    PubMed

    Cochrane, Darryl J; Harnett, Michael C

    2015-07-01

    The hip extensors are an important muscle group for sporting and functional movements, but assessing this muscle group for musculoskeletal dysfunction and strength testing has been performed in adult males and females as a prone, open-chain exercise, which provides little posture specificity for locomotive activities. Given the importance of closed-kinetic chain exercises for strength and rehabilitation requirements, there is an obvious need to assess hip extension but little is known about executing a closed-kinetic chain hip extension exercise for adolescents. Therefore, the aim of this study was to ascertain hip extensor muscle activation pattern and force production using a semi-orthostatic position while performing a unilateral closed-kinetic hip extension exercise. Fourteen young healthy adolescent male participants performed three maximal repetitions of closed-kinetic chain left and right hip extension on a glute machine. Electromyography (EMG) from left and right rectus femoris (RF), gluteus maximus (GM), and biceps femoris (BF) was recorded and RF, GM, and BF EMG mean amplitude, EMG area and onset times were analysed. There was no significant difference in EMG mean amplitude and EMG area between RF, GM, and BF but the right hip showed a significantly higher EMG (p < 0.05) than the left hip. The relative onset difference between GM and BF was similar in both hips, suggesting that there was no dominant muscle firing order. The closed-kinetic chain hip extension could be advantageous when assessing neuromuscular function and training muscle strength because the semi-orthostatic position of hip extension exercise provides a posture similar to functional activities.

  4. Proximal Rectus Femoris Avulsion: Ultrasonic Diagnosis and Nonoperative Management

    PubMed Central

    Esser, Stephan; Jantz, David; Hurdle, Mark F.; Taylor, Walter

    2015-01-01

    Objective To present a case of ultrasonic diagnosis and nonoperative management of a complete proximal rectus femoris avulsion in a National Collegiate Athletic Association Division 1 soccer goalkeeper. Background While delivering a goal kick, a previously uninjured 24-year-old collegiate soccer goalkeeper had the sudden onset of right anterior thigh pain. He underwent rehabilitation with rapid resolution of his presenting pain but frequent intermittent recurrence of anterior thigh pain. After he was provided a definitive diagnosis with musculoskeletal ultrasound, he underwent an extended period of rehabilitation and eventually experienced complete recovery without recurrence. Differential Diagnosis Rectus femoris avulsion, rectus femoris strain or partial tear, inguinal hernia, or acetabular labral tear. Treatment Operative and nonoperative options were discussed. In view of the player's recovery, nonoperative options were pursued with a good result. Uniqueness Complete proximal rectus femoris avulsions are rare. Our case contributes to the debate on whether elite-level kicking and running athletes can return to full on-field performance without surgery. Conclusions Complete proximal rectus femoris avulsions can be treated effectively using nonoperative measures with good preservation of function even in the elite-level athlete. In addition, musculoskeletal ultrasound is an excellent tool for on-site evaluation and may help guide prognosis and management. PMID:25978099

  5. Back and hip extensor muscles fatigue in healthy subjects: task-dependency effect of two variants of the Sorensen test

    PubMed Central

    Champagne, Annick; Descarreaux, Martin

    2008-01-01

    Paraspinal muscle fatigability during various trunk extension tests has been widely investigated by electromyography (EMG), and its task-dependency is established recently. Hip extensor muscle fatigability during the Sorensen test has been reported. The aim of the present experiments was to evaluate the task-dependency of back and hip extensor muscle fatigue during two variants of the Sorensen test. We hypothesized that the rate of muscular fatigue of the hip and back extensor muscles varies according to the test position. Twenty healthy young males with no history of low back pain volunteered to participate in this cross-sectional study. They were asked to perform two body weight-dependent isometric back extension tests (S1 = Sorensen test; S2 = modified Sorensen on a 45° Roman chair). Surface EMG activity of the paraspinal muscles (T10 and L5 levels) and hip extensor muscles (gluteus maximus; biceps femoris) was recorded, and muscular fatigue was assessed through power spectral analysis of the EMG data by calculating the rate of median power frequency change. We observed hip extensor muscle fatigue simultaneously with paraspinal muscle fatigue during both Sorensen variants. However, only L5 level EMG fatigue indices showed a task-dependency effect between S1 and S2. Hip extensor muscles appear to contribute to load sharing of the upper body mass during both Sorensen variants, but to a different extent because L5 level fatigue differs between the Sorensen variants. Our findings suggest that task-dependency has to be considered when EMG variables are compared between two types of lumbar muscle-fatiguing tasks. PMID:18813961

  6. Electromechanical delay of the hamstrings during eccentric muscle actions in males and females: Implications for non-contact ACL injuries.

    PubMed

    De Ste Croix, Mark B A; ElNagar, Youssif O; Iga, John; James, David; Ayala, Francisco

    2015-12-01

    Sex differences in neuromuscular functioning has been proposed as one of the factors behind an increased relative risk of non-contact anterior cruciate ligament (ACL) injury in females. The aim of this study was to explore sex differences in electromechanical delay (EMD) of the hamstring muscles during eccentric muscle actions and during a range of movement velocities. This study recruited 110 participants (55 males, 55 females) and electromyography of the semitendinosus, semimembranosus and biceps femoris was determined during eccentric actions at 60, 120 and 240°/s. No significant sex differences were observed irrespective of muscle examined or movement velocity. Irrespective of sex EMD significantly increased with increasing movement velocity (P < 0.01). There was no significant difference in the EMD of the 3 muscles examined. Our findings suggest that during eccentric actions of the hamstrings that there are no sex differences, irrespective of movement velocity. This would suggest that other factors are probably responsible for the increased relative risk of non-contact ACL injury in females compared to males. PMID:26522999

  7. Testing procedures for SLAP lesions of the shoulder involving contraction and torsion of biceps long head and glenohumeral glides.

    PubMed

    Misra, Sumeer; Watson, Lyn; Taylor, Nicholas F; Green, Rodney A; Hairodin, Zaki

    2011-11-01

    Testing procedures for SLAP lesions of the shoulder can combine resisted elbow flexion, forearm pronation and supination, and glenohumeral glides. These procedures reproduce symptoms by increasing biceps long head active tension or passive torsion, and by placing the shoulder in an unstable position. We compared activation of biceps long head and pain intensity, between supinated and pronated forearm positions, between different glides, and between individuals with and without shoulder impairment. A case control study. Twelve participants with suspected SLAP lesions and twelve with no history of shoulder injury volunteered. Electromyography measured muscle activity in biceps long head, normalised against maximum voluntary isometric contraction (MVIC). Subjective pain intensity scores were recorded. Biceps long head activity was greater in forearm supination (mean 39% MVIC) than pronation (mean 24% MVIC), but pain was higher in pronation (mean 4.5/10) than supination (3.2/10). Biceps long head activity was greater when testing without a glide, but there was no difference in pain comparing the glide conditions. The impaired group experienced more pain (mean 3.9/10) than controls (mean 0.3/10) but there was no difference in shoulder muscle activity. No one combination of testing procedures appeared to be diagnostic of SLAP lesions in our sample. This study supports the theory that biceps long head acts as a stabiliser of the shoulder, and suggests that clinical testing procedures for SLAP lesions may need to inhibit biceps long head activity. The addition of glides to SLAP testing procedures did not affect the reproduction of pain.

  8. Design, Development and Testing of a Low-Cost sEMG System and Its Use in Recording Muscle Activity in Human Gait

    PubMed Central

    Supuk, Tamara Grujic; Skelin, Ana Kuzmanic; Cic, Maja

    2014-01-01

    Surface electromyography (sEMG) is an important measurement technique used in biomechanical, rehabilitation and sport environments. In this article the design, development and testing of a low-cost wearable sEMG system are described. The hardware architecture consists of a two-cascade small-sized bioamplifier with a total gain of 2,000 and band-pass of 3 to 500 Hz. The sampling frequency of the system is 1,000 Hz. Since real measured EMG signals are usually corrupted by various types of noises (motion artifacts, white noise and electromagnetic noise present at 50 Hz and higher harmonics), we have tested several denoising techniques, both on artificial and measured EMG signals. Results showed that a wavelet—based technique implementing Daubechies5 wavelet and soft sqtwolog thresholding is the most appropriate for EMG signals denoising. To test the system performance, EMG activities of six dominant muscles of ten healthy subjects during gait were measured (gluteus maximus, biceps femoris, sartorius, rectus femoris, tibialis anterior and medial gastrocnemius). The obtained EMG envelopes presented against the duration of gait cycle were compared favourably with the EMG data available in the literature, suggesting that the proposed system is suitable for a wide range of applications in biomechanics. PMID:24811078

  9. Meat pH and meat fibre direction effects on moisture diffusivity in salted ham muscles dried at 5 °C.

    PubMed

    Gou, P; Comaposada, J; Arnau, J

    2002-05-01

    The effects of meat pH and meat fibre direction on the effective moisture diffusivity coefficient (D(e)) in salted ham muscles dried at 5 °C and 80% of air relative humidity were studied. Parallelepipedic meat samples from different muscles in the ham (Gluteus medius, Semimembranosus and Biceps femoris) were salted (0.08 kg NaCl/kg d.m.) and drying was only allowed through two faces of the sample by covering the other faces with PVC film. D(e) values were determined by Fick's 2nd law. D(e) parallel to the meat fibre direction in samples of Gluteus medius muscles was not affected by pH in the range 5.3-6.7. No significative differences in D(e) between the three muscles were detected (D(e) values ranged from 2.03×10(-11) to 2.55×10(-11) m(2)/s). D(e) perpendicular to meat fibre direction was 31% lower than D(e) parallel. The fibre direction effect was independent of the muscle. PMID:22063909

  10. Muscle Activation and Estimated Relative Joint Force During Running with Weight Support on a Lower-Body Positive-Pressure Treadmill.

    PubMed

    Jensen, Bente R; Hovgaard-Hansen, Line; Cappelen, Katrine L

    2016-08-01

    Running on a lower-body positive-pressure (LBPP) treadmill allows effects of weight support on leg muscle activation to be assessed systematically, and has the potential to facilitate rehabilitation and prevent overloading. The aim was to study the effect of running with weight support on leg muscle activation and to estimate relative knee and ankle joint forces. Runners performed 6-min running sessions at 2.22 m/s and 3.33 m/s, at 100%, 80%, 60%, 40%, and 20% body weight (BW). Surface electromyography, ground reaction force, and running characteristics were measured. Relative knee and ankle joint forces were estimated. Leg muscles responded differently to unweighting during running, reflecting different relative contribution to propulsion and antigravity forces. At 20% BW, knee extensor EMGpeak decreased to 22% at 2.22 m/s and 28% at 3.33 m/s of 100% BW values. Plantar flexors decreased to 52% and 58% at 20% BW, while activity of biceps femoris muscle remained unchanged. Unweighting with LBPP reduced estimated joint force significantly although less than proportional to the degree of weight support (ankle). It was concluded that leg muscle activation adapted to the new biomechanical environment, and the effect of unweighting on estimated knee force was more pronounced than on ankle force.

  11. Effect of an Eight-Week Ballroom Dancing Program on Muscle Architecture in Older Adults Females.

    PubMed

    Cepeda, Christina C P; Lodovico, Angélica; Fowler, Neil; Rodacki, André L F

    2015-10-01

    Aging is related to a progressive remodeling of the neuromuscular system, which includes muscle mass, strength, and power reductions. This study investigated the effect of an eight-week dance program on fascicle pennation angle, fascicle length, and thickness of the vastus lateralis (VL), tibialis anterior (TA), biceps femoris (BF), and gastrocnemius medialis (GM) muscles using ultrasound images. Thirty-four healthy older women were randomly assigned to either a dancing (DG: n = 19, 69.1 ± 6.5 years, 72.5 ± 11.7 kg) or control group (CG: n = 15, 71.5 ± 7.4 years, 70.9 ± 9.3 kg). After training, the DG showed greater (p < .05) thickness for VL (16%), TA (17%), BF (19%), and GM (15%); pennation angle for VL (21%), TA (23%), BF (21%), and GM (17%); and fascicle length for VL (11%), TA (12%), BF (10%), and GM (10%). These findings suggest that dance training was effective to change the lower limb muscle architecture in older female adults.

  12. Supersonic shear imaging provides a reliable measurement of resting muscle shear elastic modulus.

    PubMed

    Lacourpaille, Lilian; Hug, François; Bouillard, Killian; Hogrel, Jean-Yves; Nordez, Antoine

    2012-03-01

    The aim of the present study was to assess the reliability of shear elastic modulus measurements performed using supersonic shear imaging (SSI) in nine resting muscles (i.e. gastrocnemius medialis, tibialis anterior, vastus lateralis, rectus femoris, triceps brachii, biceps brachii, brachioradialis, adductor pollicis obliquus and abductor digiti minimi) of different architectures and typologies. Thirty healthy subjects were randomly assigned to the intra-session reliability (n = 20), inter-day reliability (n = 21) and the inter-observer reliability (n = 16) experiments. Muscle shear elastic modulus ranged from 2.99 (gastrocnemius medialis) to 4.50 kPa (adductor digiti minimi and tibialis anterior). On the whole, very good reliability was observed, with a coefficient of variation (CV) ranging from 4.6% to 8%, except for the inter-operator reliability of adductor pollicis obliquus (CV = 11.5%). The intraclass correlation coefficients were good (0.871 ± 0.045 for the intra-session reliability, 0.815 ± 0.065 for the inter-day reliability and 0.709 ± 0.141 for the inter-observer reliability). Both the reliability and the ease of use of SSI make it a potentially interesting technique that would be of benefit to fundamental, applied and clinical research projects that need an accurate assessment of muscle mechanical properties.

  13. Motoneuronal and muscle synergies involved in cat hindlimb control during fictive and real locomotion: a comparison study.

    PubMed

    Markin, Sergey N; Lemay, Michel A; Prilutsky, Boris I; Rybak, Ilya A

    2012-04-01

    We compared the activity profiles and synergies of spinal motoneurons recorded during fictive locomotion evoked in immobilized decerebrate cat preparations by midbrain stimulation to the activity profiles and synergies of the corresponding hindlimb muscles obtained during forward level walking in cats. The fictive locomotion data were collected in the Spinal Cord Research Centre, University of Manitoba, and provided by Dr. David McCrea; the real locomotion data were obtained in the laboratories of M. A. Lemay and B. I. Prilutsky. Scatterplot representation and minimum spanning tree clustering algorithm were used to identify the possible motoneuronal and muscle synergies operating during both fictive and real locomotion. We found a close similarity between the activity profiles and synergies of motoneurons innervating one-joint muscles during fictive locomotion and the profiles and synergies of the corresponding muscles during real locomotion. However, the activity patterns of proximal nerves controlling two-joint muscles, such as posterior biceps and semitendinosus (PBSt) and rectus femoris (RF), were not uniform in fictive locomotion preparations and differed from the activity profiles of the corresponding two-joint muscles recorded during forward level walking. Moreover, the activity profiles of these nerves and the corresponding muscles were unique and could not be included in the synergies identified in fictive and real locomotion. We suggest that afferent feedback is involved in the regulation of locomotion via motoneuronal synergies controlled by the spinal central pattern generator (CPG) but may also directly affect the activity of motoneuronal pools serving two-joint muscles (e.g., PBSt and RF). These findings provide important insights into the organization of the spinal CPG in mammals, the motoneuronal and muscle synergies engaged during locomotion, and their afferent control.

  14. Effects of the lower extremities muscle activation during muscular strength training on an unstable platform with magneto-rheological dampers

    NASA Astrophysics Data System (ADS)

    Piao, YongJun; Choi, YounJung; Kim, JungJa; Kwan, TaeKyu; Kim, Nam-Gyun

    2009-03-01

    Adequate postural balance depends on the spatial and temporal integration of vestibular, visual, and somatosensory information. Especially, the musculoskeletal function (range of joint, flexibility of spine, muscular strength) is essential in maintaining the postural balance. Muscular strength training methods include the use of commercialized devices and repeatable resistance training tools (rubber band, ball, etc). These training systems cost high price and can't control of intensity. Thus we suggest a new training system which can adjust training intensity and indicate the center of pressure of a subject while the training was passively controlled by applying controlled electric current to the Magneto- Rheological damper. And we performed experimental studies on the muscular activities in the lower extremities during maintaining, moving and pushing exercises on an unstable platform with Magneto rheological dampers. A subject executed the maintaining, moving and pushing exercises which were displayed in a monitor. The electromyographic signals of the eight muscles in lower extremities were recorded and analyzed in the time and frequency domain: the muscles of interest were rectus femoris, biceps femoris, tensor fasciae latae, vastus lateralis, vastus medialis, gastrocnemius, tibialis anterior, and soleus. The experimental results showed the difference of muscular activities at the four moving exercises and the nine maintaining exercises. The rate of the increase in the muscular activities was affected by the condition of the unstable platform with MR dampers for the maintaining and moving exercises. The experimental results suggested the choice of different maintaining and moving exercises could selectively train different muscles with varying intensity. Furthermore, the findings also suggested the training using this system can improve the ability of postural balance.

  15. Mapping of intramuscular tenderness and muscle fiber orientation of muscles in the beef round.

    PubMed

    Senaratne, L S; Calkins, C R; de Mello, A S; Pokharel, S; Hinkle, J B

    2010-09-01

    Intramuscular tenderness variation and muscle fiber orientation of beef M. adductor femoris (AF), M. biceps femoris (BF), M. gracilis (GL), M. pectineus (PT), M. sartorius (SR), M. semimembranosus (SM), M. semitendinosus (SO), M. vastus intermedius (VI), M. vastus medialis (VM), and M. vastus lateralis (VL) were investigated. The USDA Choice boxed beef subprimals were purchased and aged for 14 d from boxed date. The AF, BF, GL, PT, SR, SM, SO, VI, VM, and VL (n = 10 each) were fabricated from subprimals. Crust-frozen AF, BF, SO, SM, and VL were cut into 2.54-cm steaks perpendicular to the long axis and grilled (71 degrees C). The PT, SR, VI, and VM were grilled (71 degrees C) as whole muscles, whereas the GL was grilled after cutting into anterior and posterior regions. Grilled muscles were cut into equal size sections perpendicular to long axis of muscles. Location-specific cores were prepared from each steak/section, and Warner-Bratzler shear force (WBSF) was measured. The muscle fiber orientations of BF, PT, and VI were bipennate, SR and SO were fusiform, and AD, SM, VL, GL, and VM were unipennate. The overall mean WBSF values for BF, SO, AF, SM, PT, SR, GL, VI, VM, and VL were 5.62, 4.86, 4.18, 4.90, 3.76, 4.44, 4.75, 4.78, 4.24, and 6.53 kg, respectively. Based on WBSF values, PT was tender, BF and VL were tough, and VM, VI, SM, GL SR, AF, and SO were intermediate. The first 2 proximal steaks of long head BF were more tender than the rest (P < 0.05). In the SO, the tenderness decreased from the middle of the muscle to both ends (P < 0.05). The anterior sides of the long head BF and SO were tougher than their posterior sides (P < 0.05).The first 4 steaks of the SM were more tender than the rest of the muscle (P < 0.05). There was a significant tenderness increment from the middle of the AF and SR to both ends of each muscle (P < 0.05). The medial side of the VI was more tender than its lateral side (P < 0.05). The VM had its smallest shear force value at the

  16. Profunda Femoris Artery Perforator Propeller Flap: A Valid Method to Cover Complicated Ischiatic Pressure Sores.

    PubMed

    Scalise, Alessandro; Tartaglione, Caterina; Bolletta, Elisa; Pierangeli, Marina; Di Benedetto, Giovanni

    2015-08-01

    We report the case of a 50-year-old paraplegic man with a complicated grade III/IV ischiatic pressure sore treated with a propeller flap based on the first perforator of the profunda femoris artery. Our aim was to surgically reconstruct an ischiatic pressure sore in a patient with ankylosis using a fasciocutaneous perforator propeller flap obtained from the posterior region of the thigh. Our decision to perform a profunda femoris artery perforator propeller flap reconstruction was mainly due to the anatomical contiguity of the flap with the site of the lesion and the good quality of the skin harvested from the posterior region of the thigh. The use of the perforator fasciocutaneous flap represents a muscle-sparing technique, providing a better long-term result in surgical reconstruction. The choice of the 180-degree propeller flap was due to its ability to provide a good repair of the pressure ulcer and to pass over the ischiatic prominence in the patient in the forced decubitus position. The operatory course did not present any kind of complication. Using this reconstructive treatment, we have obtained complete coverage of the ischiatic pressure sore.

  17. Comparative Analysis of Muscle Transcriptome between Pig Genotypes Identifies Genes and Regulatory Mechanisms Associated to Growth, Fatness and Metabolism

    PubMed Central

    Ayuso, Miriam; Fernández, Almudena; Núñez, Yolanda; Benítez, Rita; Isabel, Beatriz; Barragán, Carmen; Fernández, Ana Isabel; Rey, Ana Isabel; Medrano, Juan F.; Cánovas, Ángela; González-Bulnes, Antonio; López-Bote, Clemente; Ovilo, Cristina

    2015-01-01

    Iberian ham production includes both purebred (IB) and Duroc-crossbred (IBxDU) Iberian pigs, which show important differences in meat quality and production traits, such as muscle growth and fatness. This experiment was conducted to investigate gene expression differences, transcriptional regulation and genetic polymorphisms that could be associated with the observed phenotypic differences between IB and IBxDU pigs. Nine IB and 10 IBxDU pigs were slaughtered at birth. Morphometric measures and blood samples were obtained and samples from Biceps femoris muscle were employed for compositional and transcriptome analysis by RNA-Seq technology. Phenotypic differences were evident at this early age, including greater body size and weight in IBxDU and greater Biceps femoris intramuscular fat and plasma cholesterol content in IB newborns. We detected 149 differentially expressed genes between IB and IBxDU neonates (p < 0.01 and Fold-Change > 1. 5). Several were related to adipose and muscle tissues development (DLK1, FGF21 or UBC). The functional interpretation of the transcriptomic differences revealed enrichment of functions and pathways related to lipid metabolism in IB and to cellular and muscle growth in IBxDU pigs. Protein catabolism, cholesterol biosynthesis and immune system were functions enriched in both genotypes. We identified transcription factors potentially affecting the observed gene expression differences. Some of them have known functions on adipogenesis (CEBPA, EGRs), lipid metabolism (PPARGC1B) and myogenesis (FOXOs, MEF2D, MYOD1), which suggest a key role in the meat quality differences existing between IB and IBxDU hams. We also identified several polymorphisms showing differential segregation between IB and IBxDU pigs. Among them, non-synonymous variants were detected in several transcription factors as PPARGC1B and TRIM63 genes, which could be associated to altered gene function. Taken together, these results provide information about candidate

  18. Does feed restriction and re-alimentation differently affect lipid content and metabolism according to muscle type in pigs (Sus scrofa)?

    PubMed

    Gondret, Florence; Lebret, Bénédicte

    2007-06-01

    This study aimed to investigate whether feed restriction and re-alimentation differently affect lipid content and activities of lipogenic or catabolic enzymes according to muscle types in pigs. At around 28 kg body mass (BW), sixty pigs (n=30 per group) were allocated to either ad libitum (AL) or restricted/re-feeding (RA) regimens. After feed restriction (80 kg BW), lipid content was reduced (P<0.01) in the oxidative rhomboideus (RH) as in the glycolytic biceps femoris (BF) muscles of RA pigs compared with AL pigs. Lower activities (P<0.05) of the lipogenic enzymes fatty acid synthase (FAS) and malic enzyme (ME) were observed in the RH but not in the BF of RA vs. AL pigs. After re-feeding (110 kg BW), lipid content was restored in the RH, but was still 12% lower (P<0.05) in the BF of RA compared with AL pigs. In the RH, the trend for an enhanced FAS activity and for a smaller weight-related decrease of ME activity in RA pigs than AL pigs during re-feeding, may have contributed to the muscle fat recovery observed in the RA pigs. In the BF, higher oxidative enzyme activities (P<0.10) in RA pigs compared to AL pigs might explain the incomplete lipid recovery observed after re-feeding in the former animals. In conclusion, metabolic activities in response to restriction and re-feeding differed according to muscle metabolic type.

  19. Effect of Feeding Palm Oil By-Products Based Diets on Muscle Fatty Acid Composition in Goats

    PubMed Central

    Abubakr, Abdelrahim; Alimon, Abdul Razak; Yaakub, Halimatun; Abdullah, Norhani; Ivan, Michael

    2015-01-01

    The present study aims to evaluate the effects of feeding palm oil by-products based diets on different muscle fatty acid profiles in goats. Thirty-two Cacang × Boer goats were randomly assigned to four dietary treatments: (1) control diet (CD), (2) 80% decanter cake diet (DCD), (3) 80% palm kernel cake diet (PKCD) and (4) CD plus 5% palm oil (PO) supplemented diet (CPOD). After 100 days of feeding, four goats from each group were slaughtered and longissimus dorsi (LD), infraspinatus (IS) and biceps femoris (BF) were sampled for analysis of fatty acids. Goats fed the PKCD had higher (P<0.05) concentration of lauric acid (C12:0) than those fed the other diets in all the muscles tested. Compared to the other diets, the concentrations of palmitic acid (C16:0) and stearic acid (C18:0) were lower (P<0.05) and that of linoleic acid (C18:2 n-6) was higher (P<0.05) in the muscles from goats fed the CD. It was concluded that palm kernel cake and decanter cake can be included in the diet of goats up to 80% with more beneficial than detrimental effects on the fatty acid profile of their meat. PMID:25789610

  20. Meat quality and muscle fibre type characteristics of Southdown Rams from high and low backfat selection lines.

    PubMed

    Kadim, I T; Purchas, R W; Davies, A S; Rae, A L; Barton, R A

    1993-01-01

    Characteristics of the meat of 15-18-month Southdown rams from lines selected for high or low backfat depths (assessed ultrasonically at position C over the last rib) were compared. Half of the carcasses were electrically stimulated (ES) and within each carcass post-mortem treatments chosen to produce effects on meat tenderness were ageing periods of 1 or 15 days (Semimembranosus), early or delayed chilling (Biceps femoris), and trimming of the s.c. fat cover (Longissimus dorsi). These treatments had the expected effects on shear values, but the sizes of the effects were little affected by selection line or ES treatment. Selection line did not have any direct effects on shear values, reflectance values at several wavelengths, waterholding capacity, cooking loss or sarcomere length. The Semitendinosus muscle had a higher proportion of predominantly oxidative fibres for the high-backfat line, based on succinic dehydrogenase activity (P < 0·05), but there was no line difference in alkaline-stable ATPase activity in the same muscle. Muscle fibre diameter was similar for the two lines.

  1. Long head of the biceps tendon pathology

    PubMed Central

    Ibáñez, Maximiliano; Calvo, Ana Belén; Alvarez, Victoria; Lepore, Salvador; Ibañez, Federico; Reybet, Juan; Vedova, Franco Della; Aeschlimann, Mauro; Taborro, Betina

    2015-01-01

    Introduction: Disorders of the long head of the biceps tendon can exist in conjunction with other shoulder pathologies. It was proposed as a cause of pain in patients with rotator cuff injury. A detailed history, thorough physical examination and radiographical evaluation are necessary for a correct diagnosis. The aim of our study was to describe the surgical technique and analyze the results obtained in patients based on the same. Materials and Methods: Were included in this retrospective study 70 patients who had lesions in the long head of the biceps tendon, diagnosed with MRI treated at our institution with arthroscopic biotenodesis technique of the tendon with interference screw in the lower portion of the bicipital groove since January 2009 to January 2012. Functional clinical evaluation was performed with the appropriate scores for the disease (ASES, Rowe, Simple Shoulder Test, Constant Murley). Pain was evaluated using Visual Analog Scale. Results: The Rowe score was 86 points, 81 points ASES, SST 9 points, Constant and Murley 87 points. The VAS showed poor post surgical pain. At the time, no associated deformity similar to a Popeye sign was observed. Discussion: The decision to perform a surgical management of the long head of the biceps pathology depends on the clinical presentation, thorough physical examination with specific test, the presence of associated pathologies and failure of nonsurgical treatment.

  2. Biceps Tenodesis for Type II SLAP Tears.

    PubMed

    Tayrose, Gregory A; Karas, Spero G; Bosco, Joseph

    2015-06-01

    Tears of the superior glenoid labrum are a common cause of shoulder pain and disability, especially in overhead athletes such as pitchers, swimmers, and volleyball players. Type II SLAP lesions have been the most clinically important superior labral pathology, and the management of this lesion has been a very controversial topic. Currently, there are no high level studies in the literature to guide treatment. While the few level 3 and level 4 evidence studies that are available following arthroscopic repair of type II SLAP lesions all report reasonable overall patient satisfaction, persistent postoperative pain is common and associated with a low return to pre-injury level of sports participation. There has been a recent school of thought that biceps tenodesis, which maintains the length-tension relationship of the long head of biceps, should be the procedure of choice for patients with isolated type II SLAP lesions. The current paper reviews the role biceps tenodesis plays in the management of type II SLAP tears. PMID:26517164

  3. Biceps Tenodesis for Type II SLAP Tears.

    PubMed

    Tayrose, Gregory A; Karas, Spero G; Bosco, Joseph

    2015-06-01

    Tears of the superior glenoid labrum are a common cause of shoulder pain and disability, especially in overhead athletes such as pitchers, swimmers, and volleyball players. Type II SLAP lesions have been the most clinically important superior labral pathology, and the management of this lesion has been a very controversial topic. Currently, there are no high level studies in the literature to guide treatment. While the few level 3 and level 4 evidence studies that are available following arthroscopic repair of type II SLAP lesions all report reasonable overall patient satisfaction, persistent postoperative pain is common and associated with a low return to pre-injury level of sports participation. There has been a recent school of thought that biceps tenodesis, which maintains the length-tension relationship of the long head of biceps, should be the procedure of choice for patients with isolated type II SLAP lesions. The current paper reviews the role biceps tenodesis plays in the management of type II SLAP tears.

  4. Selective bilateral activation of leg muscles after cutaneous nerve stimulation during backward walking

    PubMed Central

    Massaad, Firas; Jansen, Karen; Bruijn, Sjoerd M.; Duysens, Jacques

    2012-01-01

    During human locomotion, cutaneous reflexes have been suggested to function to preserve balance. Specifically, cutaneous reflexes in the contralateral leg's muscles (with respect to the stimulus) were suggested to play an important role in maintaining stability during locomotor tasks where stability is threatened. We used backward walking (BW) as a paradigm to induce unstable gait and analyzed the cutaneous reflex activity in both ipsilateral and contralateral lower limb muscles after stimulation of the sural nerve at different phases of the gait cycle. In BW, the tibialis anterior (TA) reflex activity in the contralateral leg was markedly higher than TA background EMG activity during its stance phase. In addition, in BW a substantial reflex suppression was observed in the ipsilateral biceps femoris during the stance-swing transition in some participants, while for medial gastrocnemius the reflex activity was equal to background activity in both legs. To test whether the pronounced crossed responses in TA could be related to instability, the responses were correlated with measures of stability (short-term maximum Lyapunov exponents and step width). These measures were higher for BW compared with forward walking, indicating that BW is less stable. However, there was no significant correlation between these measures and the amplitude of the crossed TA responses in BW. It is therefore proposed that these crossed responses are related to an attempt to briefly slow down (TA decelerates the center of mass in the single-stance period) in the light of unexpected perturbations, such as provided by the sural nerve stimulation. PMID:22773779

  5. Arthroscopic Biceps Tenodesis From a Superior Viewing Portal in the Shoulder

    PubMed Central

    Tarleton, Andrew A.; Zhou, Liang; O'Brien, Michael J.; Savoie, Felix H.

    2015-01-01

    The purpose of this report is to describe our modification of the Verma-Trenhaile biceps tenodesis technique using a superior viewing portal that allows placement of the tenodesis site at the top of the pectoralis major tendon with interference screw fixation. The advantages of this technique include the following: (1) There is no need to exteriorize the tendon through the skin. (2) Viewing from superiorly allows a panoramic view of the groove all the way to the pectoralis major tendon insertion. (3) This panoramic view allows a more complete view of the biceps down to the muscle-tendon junction beneath the pectoralis major tendon. (4) The improved visualization permits the drill hole to be contained within the constraints of the groove. Short-term follow-up shows favorable results clinically, and no major complications have been associated with this technique. PMID:26759782

  6. Heel-strike in walking: assessment of potential sources of intra- and inter-subject variability in the activation patterns of muscles stabilizing the knee joint.

    PubMed

    Huber, Cora; Federolf, Peter; Nüesch, Corina; Cattin, Philippe C; Friederich, Niklaus F; Tscharner, Vinzenz von

    2013-04-26

    The electromyographic (EMG) signal is known to show large intra-subject and inter-subject variability. Adaptation to, and preparation for, the heel-strike event have been hypothesized to be major sources of EMG variability in walking. The aim of this study was to assess these hypotheses using a principal component analysis (PCA). Two waveform shapes with distinct characteristic features were proposed based on conceptual considerations of how the neuro-muscular system might prepare for, or adapt to, the heel-strike event. PCA waveforms obtained from knee muscle EMG signals were then compared with the predicted characteristic features of the two proposed waveforms. Surface EMG signals were recorded for ten healthy adult female subjects during level walking at a self-selected speed, for the following muscles; rectus femoris, vastus medialis, vastus lateralis, semitendinosus, and biceps femoris. For a period of 200 ms before and after heel-strike, EMG power was extracted using a wavelet transformation (19-395 Hz). The resultant EMG waveforms (18 per subject) were submitted to intra-subject and inter-subject PCA. In all analyzed muscles, the shapes of the first and second principal component (PC-) vectors agreed well with the predicted waveforms. These two PC-vectors accounted for 50-60% of the overall variability, in both inter-subject and intra-subject analyses. It was also found that the shape of the first PC-vector was consistent between subjects, while higher-order PC-vectors differed between subjects. These results support the hypothesis that adaptation to, and preparation for, a variable heel-strike event are both major sources of EMG variability in walking.

  7. Simultaneous time course analysis of multiple markers based on DNA microarray in incised wound in skeletal muscle for wound aging.

    PubMed

    Hassan Gaballah, Mohammed; Fukuta, Mamiko; Maeno, Yoshitaka; Seko-Nakamura, Yoshimi; Monma-Ohtaki, Jun; Shibata, Yuka; Kato, Hideaki; Aoki, Yasuhiro; Takamiya, Masataka

    2016-09-01

    Assessment of incised wound age in skeletal muscles is important because fatal injuries are often complicated with muscle involvement. Transcriptome of injured skeletal muscle along with histopathological and immunohistochemistry staining, were analyzed to explore the biological effect of incised injuries using a mouse incised injury model. An incisional wound was made at the biceps femoris muscle of anesthetized mice, and the muscles were sampled at 6, 12, 24, 36 and 48h post-injury. DNA microarray analysis using RNA extracted from the muscle samples of 12h post-injury identified 3,655 upregulated and 3,583 downregulated genes. Referring to the results of the gene ontology and gene expression pathway analysis, time course expression of five cytokines, namely chemokine (C-C motif) ligand 4 (CCL4), chemokine (C-X-C motif) ligand 5 (CXCL5), interleukin-1 beta (IL-1β), interleukin- 6 (IL-6) and interleukin-7 (IL-7), were analyzed by quantative reverse transcription PCR (qRT-PCR). CXCL5 was the most upregulated gene throughout the post-injury period with higher expression from 6 through 36h post injury. Upregulation of CCL4 and IL-1β was also persisted until 36h post injury. IL-6 mRNA was highly and rapidly expressed at 6h post-injury followed by significant decrease at 12h. Unlike other four cytokines, IL-7 showed slow and steady increasing over time until 48h post-injury. Immunohistochemical staining of post-injury samples showed gradual mild increase of staining intensity proportional to increasing time points especially around the wound edges. The present study highlights the unique dynamics of each cytokine and reflects their roles in the process of muscle wound healing, and suggests the potential of them as a tool for forensic wound age estimation.

  8. CMB Polarization with BICEP2 and Keck-Array

    NASA Astrophysics Data System (ADS)

    Pryke, Clement; BICEP2 and Keck-Array Collaborations

    2013-01-01

    BICEP2 is an evolution from the highly successful BICEP CMB polarization experiment. In turn Keck-Array is an array of BICEP2 like receivers to achieve an additional increase in sensitivity. All these experiments are located at the South Pole in Antarctica and target the CMB B-mode polarization signal which is predicted to exist in many simpler models of Inflation at angular scales of several degrees. The design and performance of BICEP2 and Keck-Array is described and some preliminary polarization maps are presented.

  9. Muscle Activation During Exercise in Severe Acute Hypoxia: Role of Absolute and Relative Intensity

    PubMed Central

    Torres-Peralta, Rafael; Losa-Reyna, José; González-Izal, Miriam; Perez-Suarez, Ismael; Calle-Herrero, Jaime; Izquierdo, Mikel

    2014-01-01

    Abstract Torres-Peralta, Rafael, José Losa-Reyna, Miriam González-Izal, Ismael Perez-Suarez, Jaime Calle-Herrero, Mikel Izquierdo, and José A.L. Calbet. Muscle activation during exercise in severe acute hypoxia: Role of absolute and relative intensity. High Alt Med Biol 15:472–482, 2014.—The aim of this study was to determine the influence of severe acute hypoxia on muscle activation during whole body dynamic exercise. Eleven young men performed four incremental cycle ergometer tests to exhaustion breathing normoxic (FIo2=0.21, two tests) or hypoxic gas (FIo2=0.108, two tests). Surface electromyography (EMG) activities of rectus femoris (RF), vastus medialis (VL), vastus lateralis (VL), and biceps femoris (BF) were recorded. The two normoxic and the two hypoxic tests were averaged to reduce EMG variability. Peak Vo2 was 34% lower in hypoxia than in normoxia (p<0.05). The EMG root mean square (RMS) increased with exercise intensity in all muscles (p<0.05), with greater effect in hypoxia than in normoxia in the RF and VM (p<0.05), and a similar trend in VL (p=0.10). At the same relative intensity, the RMS was greater in normoxia than in hypoxia in RF, VL, and BF (p<0.05), with a similar trend in VM (p=0.08). Median frequency increased with exercise intensity (p<0.05), and was higher in hypoxia than in normoxia in VL (p<0.05). Muscle contraction burst duration increased with exercise intensity in VM and VL (p<0.05), without clear effects of FIo2. No significant FIo2 effects on frequency domain indices were observed when compared at the same relative intensity. In conclusion, muscle activation during whole body exercise increases almost linearly with exercise intensity, following a muscle-specific pattern, which is adjusted depending on the FIo2 and the relative intensity of exercise. Both VL and VM are increasingly involved in power output generation with the increase of intensity and the reduction in FIo2. PMID:25225839

  10. Complications of Distal Biceps Tendon Repair

    PubMed Central

    Amin, Nirav H.; Volpi, Alex; Lynch, T. Sean; Patel, Ronak M.; Cerynik, Douglas L.; Schickendantz, Mark S.; Jones, Morgan H.

    2016-01-01

    Background: Anatomic reinsertion of the distal biceps is critical for restoring flexion and supination strength. Single- and double-incision surgical techniques have been reported, analyzing complications and outcomes measures. Which technique results in superior clinical outcomes and the lowest associated complications remains unclear. Hypothesis: We hypothesized that rerupture rates would be similar between the 2 techniques, while nerve complications would be higher for the single-incision technique and heterotopic ossification would be more frequent with the double-incision technique. Study Design: Systematic review and meta-analysis; Level of evidence, 4. Methods: A systematic review was conducted using the PubMed, MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), SPORTSDiscus, and the Cochrane Central Register of Controlled Trials databases to identify articles reporting distal biceps ruptures up to August 2013. We included English-language articles on adult patients with a minimum of 3 cases reporting single- and double-incision techniques. Frequencies of each complication as a percentage of total cases were calculated. Fisher exact tests were used to test the association between frequencies for each repair method, with P < .05 considered statistically significant. Odds ratios with 95% CIs were also computed. Results: A total of 87 articles met the inclusion criteria. Lateral antebrachial cutaneous nerve neurapraxia was the most common complication in the single-incision group, occurring in 77 of 785 cases (9.8%). Heterotopic ossification was the most common complication in the double-incision group, occurring in 36 of 498 cases (7.2%). Conclusion: The overall frequency of reported complications is higher for single-incision distal biceps repair than for double-incision repair. The frequencies of rerupture and nerve complications are both higher for single-incision repairs while the frequency of heterotopic ossification is higher for

  11. Biceps Lesion Associated With Rotator Cuff Tears

    PubMed Central

    Jeong, Ho Yeon; Kim, Jung Youn; Cho, Nam Su; Rhee, Yong Girl

    2016-01-01

    Background: Various tenodesis methods are being used for long head of the biceps tendon lesions. However, there is no consensus on the most appropriate surgical method. Hypothesis: There are significant differences in incidence of cosmetic deformity and persistent bicipital pain between open subpectoral and arthroscopic intracuff tenodesis groups. Study Design: Cohort study; Level of evidence, 3. Methods: This study included 72 patients who underwent biceps tenodesis and rotator cuff repair between January 2009 and May 2014 and who were followed for at least 1 year. Open subpectoral tenodesis was performed in 39 patients (group A), and arthroscopic intracuff tenodesis was performed in 33 patients (group B). Results: In group A, the mean visual analog scale (VAS) score for pain during motion and mean University of California, Los Angeles (UCLA) and Constant scores significantly improved from 4.6, 18.6, and 64.5 preoperatively to 1.9, 30.5, and 86.5 at last follow-up, respectively (P < .001 for all). In group B, these scores significantly improved from 5.1, 17.6, and 62.9 preoperatively to 1.8, 31.5, and 85.9 at last follow-up, respectively (P < .001 for all). Popeye deformity was noted in 2 (5.2%) patients from group A and 5 (15.6%) patients from group B (P = .231). Additionally, persistent bicipital tenderness was noted in 1 (2.6%) patient from group A and 8 (24.2%) patients from group B (P = .012). Conclusion: Both open subpectoral tenodesis and arthroscopic intracuff tenodesis show good clinical outcomes for long head of the biceps tendon lesions. However, open subpectoral tenodesis may be more appropriate, considering the low incidence of Popeye deformity and tenderness. PMID:27231699

  12. Activation and aponeurosis morphology affect in vivo muscle tissue strains near the myotendinous junction.

    PubMed

    Fiorentino, Niccolo M; Epstein, Frederick H; Blemker, Silvia S

    2012-02-23

    Hamstring strain injury is one of the most common injuries in athletes, particularly for sports that involve high speed running. The aims of this study were to determine whether muscle activation and internal morphology influence in vivo muscle behavior and strain injury susceptibility. We measured tissue displacement and strains in the hamstring muscle injured most often, the biceps femoris long head muscle (BFLH), using cine DENSE dynamic magnetic resonance imaging. Strain measurements were used to test whether strain magnitudes are (i) larger during active lengthening than during passive lengthening and (ii) larger for subjects with a relatively narrow proximal aponeurosis than a wide proximal aponeurosis. Displacement color maps showed higher tissue displacement with increasing lateral distance from the proximal aponeurosis for both active lengthening and passive lengthening, and higher tissue displacement for active lengthening than passive lengthening. First principal strain magnitudes were averaged in a 1cm region near the myotendinous junction, where injury is most frequently observed. It was found that strains are significantly larger during active lengthening (0.19 SD 0.09) than passive lengthening (0.13 SD 0.06) (p<0.05), which suggests that elevated localized strains may be a mechanism for increased injury risk during active as opposed to passive lengthening. First principal strains were higher for subjects with a relatively narrow aponeurosis width (0.26 SD 0.15) than wide (0.14 SD 0.04) (p<0.05). This result suggests that athletes who have BFLH muscles with narrow proximal aponeuroses may have an increased risk for BFLH strain injuries.

  13. Muscle glycogen levels and blood metabolites in reindeer (Rangifer tarandus tarandus L.) after transport and lairage.

    PubMed

    Wiklund, E; Andersson, A; Malmfors, G; Lundström, K

    1996-01-01

    A total of 66 reindeer cows and calves were included in a study on the effects of supplementary feeding, transport and lairage on muscle glycogen content, ultimate pH and blood metabolite values. Thirty reindeer (10 not transported, 20 transported 800 km) received no supplementary feed (groups A-C), another 30 animals (10 not transported, 20 transported 1000 km) were given a supplementary reindeer feed mixture 2 months prior to slaughter (groups D-F) and six animals, which had been part of a feeding experiment, were fed for 5 months and slaughtered at the research unit. Glycogen determinations and pH measurements were made in m. longissimus, m. biceps femoris and m. triceps brachii. Blood samples were collected at slaughter and muscle samples were taken 30 min after slaughter. Ultimate pH was measured 30 hr post mortem. The glycogen content in the muscles of groups A-C was very low (100-200 mmol/kg). In groups D-G, the glycogen content was equivalent to normal beef muscle values (300-500 mmol/kg). The values of the blood metabolites urea and creatinine, both of which could indicate protein catabolism caused by stress, were significantly (p < 0.05) higher in animals not having received supplemental feed (groups A-C). Alkaline phosphatase values were significantly (p < 0.05) higher in supplemental fed animals (groups D-G), indicating that their nutritional status was good. Total protein values were significantly (p < 0.05) higher in groups A, D, E and F compared to the other groups. Lorry transport did not significantly (p > 0.05) reduce the muscle glycogen content. Lairage (groups C and F) showed no negative effect on the parameters examined. These results suggest that the animals' physical condition and nutritional status have a considerable effect on their ability to tolerate various stress factors, such as lorry transport and lairage. PMID:22060679

  14. Knee extensor torque and quadriceps femoris EMG during perceptually-guided isometric contractions.

    PubMed

    Pincivero, D M; Coelho, A J; Campy, R M; Salfetnikov, Y; Suter, E

    2003-04-01

    The aim of this study was to examine superficial quadriceps femoris (QF) EMG and torque at perceived voluntary contraction efforts. Thirty subjects (15 males, 15 females) performed 9, 5 s, sub-maximal contractions at prescribed levels of perceived voluntary effort at points 1-9 on an 11-point scale (0-10), in a random order. Surface electromyograms (EMG) of the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscles, as well as QF peak torque (PT), average torque (AT), and torque coefficient of variation (C.V.), were sampled. The raw EMG signals were full-wave rectified and integrated over the middle three s of each contraction. The sampled EMG signals, and PT and AT at each perceived exertion level were normalized to the average of three maximal voluntary contractions. The normalized EMG and torque values at each perceived exertion level were then compared to equivalent percent values (i.e., 10% at a perceived level of 1). The results demonstrated that at all perceived exertion levels, with the exception of the RF at a level of 2 which was equivalent to 20%, and the VL and RF muscles at a level 1 in which activation was greater than 10%, activation was significantly less than the equivalent percent value at each point on the scale. VM EMG was found to be less than the VL and RF from contraction levels 3-9. PT was shown to be less than the equivalent percent values at contraction levels 6-9. The AT was found to be lower than the expected percent value at perceived effort levels 2-9. Torque C.V. was not found to be different across the range of perceived effort. The major findings of this study suggested that humans over-estimate voluntary QF muscle torque when guided by perceptual sensations. It is also suggested that the produced EMG signals revealed a reliance on the VL muscle for knee extensor torque generation at sub-maximal levels.

  15. REHABILITATION OF A SURGICALLY REPAIRED RUPTURE OF THE DISTAL BICEPS TENDON IN AN ACTIVE MIDDLE AGED MALE: A CASE REPORT

    PubMed Central

    Sayers, Stephen P.; LaFontaine, Tom; Scheussler, Scott

    2012-01-01

    Background: Complete rupture of the distal tendon of the biceps brachii is relatively rare and there is little information to guide therapists in rehabilitation after this injury. The purposes of this case report are to review the rehabilitation concepts used for treating such an injury, and discuss how to modify exercises during rehabilitation based on patient progression while adhering to physician recommended guidelines and standard treatment protocols. Case Presentation: The patient was an active 38‐year old male experienced in weight‐training. He presented with a surgically repaired right distal biceps tendon following an accident on a trampoline adapted with a bungee suspension harness. The intervention focused on restoring range of motion and strengthening of the supporting muscles of the upper extremity without placing undue stress on the biceps brachii. Outcomes: The patient was able to progress from a moderate restriction in ROM to full AROM two weeks ahead of the physician's post‐operative orders and initiate a re‐strengthening protocol by the eighth week of rehabilitation. At the eighth post‐operative week the patient reported no deficits in functional abilities throughout his normal daily activities with his affected upper extremity. Discussion: The results of this case report strengthen current knowledge regarding physical therapy treatment for a distal biceps tendon repair while at the same time providing new insights for future protocol considerations in active individuals. Most current protocols do not advocate aggressive stretching, AROM, or strengthening of a surgically repaired biceps tendon early in the rehabilitation process due to the fear of a re‐rupture. In the opinion of the authors, if full AROM can be achieved before the 6th week of rehabilitation, initiating a slow transition into light strengthening of the biceps brachii may be possible. Level of evidence: 4‐Single Case report PMID:23316429

  16. Evaluation of Electromyographic Biofeedback for the Quadriceps Femoris: A Systematic Review

    PubMed Central

    Wasielewski, Noah J.; Parker, Tonya M.; Kotsko, Kevin M.

    2011-01-01

    Objective: To critically review evidence for the effectiveness of electromyographic biofeedback (EMGB) of the quadriceps femoris muscle in treating various knee conditions. Data Sources: Databases used to locate randomized controlled trials included PubMed (1980–2010), Cumulative Index of Nursing and Allied Health Literature (CINAHL, 1995–2007), Web of Science (1986–2010), SPORTDiscus (1990–2007), and Physiotherapy Evidence Database (PEDro). Key words were knee and biofeedback. Study Selection: The criteria for selection were clinical randomized controlled trials in which EMGB of the quadriceps femoris was used for various knee conditions of musculoskeletal origin. Trials were excluded because of research designs other than randomized controlled trials, articles published in a non-English language, inclusion of healthy research participants, inability to identify EMGB as the source of clinical improvement, and lack of pain, functional outcome, or quadriceps torque as outcome measures. Data Extraction: Twenty specific data points were abstracted from each clinical trial under the broad categories of attributes of the patient and injury, treatment variables for the EMGB group, treatment variables for the control group, and attributes of the research design. Data Synthesis: Eight trials yielded a total of 319 participants with patellofemoral pain syndrome (n = 86), anterior cruciate ligament reconstruction (n = 52), arthroscopic surgery (n = 91), or osteoarthritis (n = 90). The average methodologic score of the included studies was 4.6/10 based on PEDro criteria. Pooled analyses demonstrated heterogeneity of the included studies, rendering the interpretation of the pooled data inappropriate. The EMGB appeared to benefit short-term postsurgical pain or quadriceps strength in 3 of 4 postsurgical investigations but was ineffective for chronic knee conditions such as patellofemoral pain and osteoarthritis in all 4 studies. Because the findings are based on limited

  17. Electromyographic activity of knee stabilizer muscles during six different balance board stimuli after anterior cruciate ligament surgery.

    PubMed

    Pereira, H M; Nowotny, A H; Santos, A B A N; Cardoso, J R

    2009-01-01

    The purpose of this study was to compare the electrical activity of the knee stabilizers, in patients with ACL (anterior cruciate ligament) reconstructed and uninjured individuals during different balance board stimuli. Eleven post-surgery individuals and eleven uninjured controls participated in the study. The muscular activity of the vastus medialis obliquus, vastus lateralis, semitendinosus, biceps femoris and gastrocnemius medial were analyzed by surface electromyography during the execution of six different balance board activities. All electromyographic data were reported as percentage of RMS mean values obtained in maximal voluntary isometric contractions (MVIC) for each muscle. When comparing the individuals with ACL reconstructed and uninjured controls, minor electromyographic activity was observed (MVIC %) for all the muscles in the surgery group (P < 0.05), however, when comparing each exercise between the groups, a statistically significant difference for vastus lateralis was demonstrated in the floor exercise (P = 0.02) and for gastrocnemius on the round board (P = 0.04). Individuals ACL reconstructed presented a decrease in muscular activity during different balance board stimuli, which suggests that compensatory alterations after ACL may still exist even after a surgery to repair an ACL rupture.

  18. An Examination of Muscle Activation and Power Characteristics While Performing the Deadlift Exercise With Straight and Hexagonal Barbells.

    PubMed

    Camara, Kevin D; Coburn, Jared W; Dunnick, Dustin D; Brown, Lee E; Galpin, Andrew J; Costa, Pablo B

    2016-05-01

    The deadlift exercise is commonly performed to develop strength and power, and to train the lower-body and erector spinae muscle groups. However, little is known about the acute training effects of a hexagonal barbell vs. a straight barbell when performing deadlifts. Therefore, the purpose of this study was to examine the hexagonal barbell in comparison with the straight barbell by analyzing electromyography (EMG) from the vastus lateralis, biceps femoris, and erector spinae, as well as peak force, peak power, and peak velocity using a force plate. Twenty men with deadlifting experience volunteered to participate in the study. All participants completed a 1 repetition maximum (1RM) test with each barbell on 2 separate occasions. Three repetitions at 65 and 85% 1RM were performed with each barbell on a third visit. The results revealed that there was no significant difference for 1RM values between the straight and hexagonal barbells (mean ± SD in kg = 181.4 ± 27.3 vs. 181.1 ± 27.6, respectively) (p > 0.05). Significantly greater normalized EMG values were found from the vastus lateralis for both the concentric (1.199 ± 0.22) and eccentric (0.879 ± 0.31) phases of the hexagonal-barbell deadlift than those of the straight-barbell deadlift (0.968 ± 0.22 and 0.559 ± 1.26), whereas the straight-barbell deadlift led to significantly greater EMG values from the bicep femoris during the concentric phase (0.835 ± 0.19) and the erector spinae (0.753 ± 0.28) during the eccentric phase than the corresponding values for the hexagonal-barbell deadlift (0.723 ± 0.20 and 0.614 ± 0.21) (p ≤ 0.05). In addition, the hexagonal-barbell deadlift demonstrated significantly greater peak force (2,553.20 ± 371.52 N), peak power (1,871.15 ± 451.61 W), and peak velocity (0.805 ± 0.165) values than those of the straight-barbell deadlift (2,509.90 ± 364.95 N, 1,639.70 ± 361.94 W, and 0.725 ± 0.138 m·s, respectively) (p ≤ 0.05). These results suggest that the barbells led

  19. Light sterile neutrinos after BICEP-2

    SciTech Connect

    Archidiacono, Maria; Hannestad, Steen; Fornengo, Nicolao; Gariazzo, Stefano; Giunti, Carlo; Laveder, Marco E-mail: fornengo@to.infn.it E-mail: giunti@to.infn.it E-mail: marco.laveder@pd.infn.it

    2014-06-01

    The recent discovery of B-modes in the polarization pattern of the Cosmic Microwave Background by the BICEP2 experiment has important implications for neutrino physics. We revisit cosmological bounds on light sterile neutrinos and show that they are compatible with all current cosmological data provided that the mass is relatively low. Using CMB data, including BICEP-2, we find an upper bound of m{sub s} < 0.85 eV (2σ Confidence Level). This bound is strengthened to 0.48 eV when HST measurements of H{sub 0} are included. However, the inclusion of SZ cluster data from the Planck mission and weak gravitational measurements from the CFHTLenS project favours a non-zero sterile neutrino mass of 0.44{sup +0.11}{sub −0.16} eV. Short baseline neutrino oscillations, on the other hand, indicate a new mass state around 1.2 eV. This mass is highly incompatible with cosmological data if the sterile neutrino is fully thermalised (Δχ{sup 2} > 10). However, if the sterile neutrino only partly thermalises it can be compatible with all current data, both cosmological and terrestrial.

  20. Building the BICEP3 Test Cryostat

    NASA Astrophysics Data System (ADS)

    Walker, Samantha; Kuo, Chao-Lin; Thompson, Keith L.; Grayson, James; Karpel, Ethan; Monticue, Val; Kuo Group/Bicep3 Collaboration Team

    2016-03-01

    BICEP3, a ground-based telescope stationed in the South Pole, currently employs a cryostat to observe the polarization of the Cosmic Microwave Background, the earliest light in the Universe, by using devices that take advantage of the superconductivity transition of titanium. The cryostat consists of staggered temperature stages at 300 K, 50 K, 4 K, 2 K, 350 mK, and 250 mK that are maintained by both a pulse tube and three stage helium (He4-He3-He3) sorption refrigerator. However, currently the helium refrigerator is experiencing unanticipated heat loading which is decreasing the fridge cycle hold time and thus the number of hours that BICEP3 can observe for in a given period of time. To address this issue, this past summer I worked at Stanford University to construct a thermally-similar cryostat that will be used to test the thermal conductivities of its various internal components at subKelvin temperatures and determine the source of this heat loading.

  1. The effects of performing a one-legged bridge with hip abduction and use of a sling on trunk and lower extremity muscle activation in healthy adults

    PubMed Central

    Choi, Kyuju; Bak, Jongwoo; Cho, Minkwon; Chung, Yijung

    2016-01-01

    [Purpose] This study investigated the changes in the muscle activities of the trunk and lower limbs of healthy adults during a one-legged bridge exercise using a sling, and with the addition of hip abduction. [Subjects and Methods] Twenty-seven healthy individuals participated in this study (14 males and 13 females). The participants were instructed to perform the bridge exercises under five different conditions. Trunk and lower limb muscle activation of the erector spinae (ES), external oblique (EO), gluteus maximus (GM), and biceps femoris (BF) was measured using surface electromyography. Data analysis was performed using the mean scores of three trials performed under each condition. [Results] There was a significant increase in bilateral EO and contralateral GM with the one-legged bridge compared with the one-legged bridge with sling exercise. Muscle activation of the ipsilateral GM and BF was significantly less during the one-legged bridge exercise compared to the one-legged bridge with sling exercise, and was significantly greater during the one-legged bridge with hip abduction compared to the one-legged bridge exercise. The muscle activation of the contralateral GM and BF was significantly greater with the one-legged bridge with hip abduction compared to the general bridge exercise. [Conclusion] With the one-legged bridge with hip abduction, the ipsilateral EO, GM and BF muscle activities were significantly greater than those of the one-legged bridge exercise. The muscle activation of all trunk and contralateral lower extremity muscles increased with the bridge with sling exercises compared with general bridge exercises. PMID:27799708

  2. Quantifying the Elastic Property of Nine Thigh Muscles Using Magnetic Resonance Elastography

    PubMed Central

    Chakouch, Mashhour K.; Charleux, Fabrice; Bensamoun, Sabine F.

    2015-01-01

    Background Pathologies of the muscles can manifest different physiological and functional changes. To adapt treatment, it is necessary to characterize the elastic property (shear modulus) of single muscles. Previous studies have used magnetic resonance elastography (MRE), a technique based on MRI technology, to analyze the mechanical behavior of healthy and pathological muscles. The purpose of this study was to develop protocols using MRE to determine the shear modulus of nine thigh muscles at rest. Methods Twenty-nine healthy volunteers (mean age = 26 ± 3.41 years) with no muscle abnormalities underwent MRE tests (1.5 T MRI). Five MRE protocols were developed to quantify the shear moduli of the nine following thigh muscles at rest: rectus femoris (RF), vastus medialis (VM), vastus intermedius (VI), vastus lateralis (VL), sartorius (Sr), gracilis (Gr), semimembranosus (SM), semitendinosus (ST), and biceps (BC). In addition, the shear modulus of the subcutaneous adipose tissue was analyzed. Results The gracilis, sartorius, and semitendinosus muscles revealed a significantly higher shear modulus (μ_Gr = 6.15 ± 0.45 kPa, μ_ Sr = 5.15 ± 0.19 kPa, and μ_ ST = 5.32 ± 0.10 kPa, respectively) compared to other tissues (from μ_ RF = 3.91 ± 0.16 kPa to μ_VI = 4.23 ± 0.25 kPa). Subcutaneous adipose tissue had the lowest value (μ_adipose tissue = 3.04 ± 0.12 kPa) of all the tissues tested. Conclusion The different elasticities measured between the tissues may be due to variations in the muscles' physiological and architectural compositions. Thus, the present protocol could be applied to injured muscles to identify their behavior of elastic property. Previous studies on muscle pathology found that quantification of the shear modulus could be used as a clinical protocol to identify pathological muscles and to follow-up effects of treatments and therapies. These data could also be used for modelling purposes. PMID:26397730

  3. Ultrasound Assessment of the Rectus Femoris Cross-Sectional Area: Subject Position Implications.

    PubMed

    Hacker, Eileen Danaher; Peters, Tara; Garkova, Miglena

    2016-09-01

    Ultrasonic measurement of the rectus femoris (RF) is a novel, proxy measure for muscle strength. The impact of hip flexion/head of bed positioning on RF cross-sectional area (CSA) has not been fully explored. This study describes and compares differences in RF CSA across four degrees of hip flexion. This repeated-measures, comparative study enrolled healthy, pre-menopausal women (n = 20). RF CSA of the dominant leg was measured using the SonoSite M-Turbo ultrasound system with the head of bed at 0°, 20°, 30°, and 60°. One-way repeated measures indicated significant differences in RF CSA, F(3, 17) = 14.18, p < .001, with variation in hip flexion/head of bed elevation and significant RF CSA differences between: (a) 0° and 20°, (b) 0° and 30°, (c) 0° and 60°, and (d) 20° and 60°. Standardizing patient positioning when conducting ultrasonic measurement of RF CSA is vital for researchers who assess muscle mass.

  4. Ultrasound Assessment of the Rectus Femoris Cross-Sectional Area: Subject Position Implications.

    PubMed

    Hacker, Eileen Danaher; Peters, Tara; Garkova, Miglena

    2016-09-01

    Ultrasonic measurement of the rectus femoris (RF) is a novel, proxy measure for muscle strength. The impact of hip flexion/head of bed positioning on RF cross-sectional area (CSA) has not been fully explored. This study describes and compares differences in RF CSA across four degrees of hip flexion. This repeated-measures, comparative study enrolled healthy, pre-menopausal women (n = 20). RF CSA of the dominant leg was measured using the SonoSite M-Turbo ultrasound system with the head of bed at 0°, 20°, 30°, and 60°. One-way repeated measures indicated significant differences in RF CSA, F(3, 17) = 14.18, p < .001, with variation in hip flexion/head of bed elevation and significant RF CSA differences between: (a) 0° and 20°, (b) 0° and 30°, (c) 0° and 60°, and (d) 20° and 60°. Standardizing patient positioning when conducting ultrasonic measurement of RF CSA is vital for researchers who assess muscle mass. PMID:27090872

  5. Cortical motor representation of the rectus femoris does not differ between the left and right hemisphere.

    PubMed

    Ward, Sarah; Bryant, Adam L; Pietrosimone, Brian; Bennell, Kim L; Clark, Ross; Pearce, Alan J

    2016-06-01

    Transcranial magnetic stimulation (TMS) involves non-invasive magnetic stimulation of the brain, and can be used to explore the corticomotor excitability and motor representations of skeletal muscles. However there is a lack of motor mapping studies in the lower limb and few conducted in healthy cohorts. The cortical motor representations of muscles can vary between individuals in terms of center position and area despite having a general localized region within the motor cortex. It is important to characterize the normal range for these variables in healthy cohorts to be able to evaluate changes in clinical populations. TMS was used in this cross-sectional study to assess the active motor threshold (AMT) and cortical representation area for rectus femoris in 15 healthy individuals (11M/4F 27.3±5.9years). No differences were found between hemispheres (Left vs. Right P=0.130) for AMT. In terms of y-axis center position no differences were found between hemispheres (Left vs. Right P=0.539), or for the x-axis center position (Left vs. Right P=0.076). Similarly, no differences in calculated area of the motor representation were found (Left vs. Right P=0.699) indicating symmetry between hemispheres.

  6. MRI-Based Regional Muscle Use during Hamstring Strengthening Exercises in Elite Soccer Players.

    PubMed

    Mendez-Villanueva, Alberto; Suarez-Arrones, Luis; Rodas, Gil; Fernandez-Gonzalo, Rodrigo; Tesch, Per; Linnehan, Richard; Kreider, Richard; Di Salvo, Valter

    2016-01-01

    The present study examined site-specific hamstring muscles use with functional magnetic resonance imaging (MRI) in elite soccer players during strength training. Thirty-six players were randomized into four groups, each performing either Nordic hamstring, flywheel leg-curl, Russian belt or the hip-extension conic-pulley exercise. The transverse relaxation time (T2) shift from pre- to post-MRI were calculated for the biceps femoris long (BFl) and short (BFs) heads, semitendinosus (ST) and semimembranosus (SM) muscles at proximal, middle and distal areas of the muscle length. T2 values increased substantially after flywheel leg-curl in all regions of the BFl (from 9±8 to 16±8%), BFs (41±6-71±11%), and ST (60±1-69±7%). Nordic hamstring induced a substantial T2 increase in all regions of the BFs (13±8-16±5%) and ST (15±7-17±5%). T2 values after the Russian belt deadlift substantially increased in all regions of the BFl (6±4-7±5%), ST (8±3-11±2%), SM (6±4-10±4%), and proximal and distal regions of BFs (6±6-8±5%). T2 values substantially increased after hip-extension conic-pulley only in proximal and middle regions of BFl (11±5-7±5%) and ST (7±3-12±4%). The relevance of such MRI-based inter- and intra-muscle use in designing more effective resistance training for improving hamstring function and preventing hamstring injuries in elite soccer players should be explored with more mechanistic studies. PMID:27583444

  7. MRI-Based Regional Muscle Use during Hamstring Strengthening Exercises in Elite Soccer Players.

    PubMed

    Mendez-Villanueva, Alberto; Suarez-Arrones, Luis; Rodas, Gil; Fernandez-Gonzalo, Rodrigo; Tesch, Per; Linnehan, Richard; Kreider, Richard; Di Salvo, Valter

    2016-01-01

    The present study examined site-specific hamstring muscles use with functional magnetic resonance imaging (MRI) in elite soccer players during strength training. Thirty-six players were randomized into four groups, each performing either Nordic hamstring, flywheel leg-curl, Russian belt or the hip-extension conic-pulley exercise. The transverse relaxation time (T2) shift from pre- to post-MRI were calculated for the biceps femoris long (BFl) and short (BFs) heads, semitendinosus (ST) and semimembranosus (SM) muscles at proximal, middle and distal areas of the muscle length. T2 values increased substantially after flywheel leg-curl in all regions of the BFl (from 9±8 to 16±8%), BFs (41±6-71±11%), and ST (60±1-69±7%). Nordic hamstring induced a substantial T2 increase in all regions of the BFs (13±8-16±5%) and ST (15±7-17±5%). T2 values after the Russian belt deadlift substantially increased in all regions of the BFl (6±4-7±5%), ST (8±3-11±2%), SM (6±4-10±4%), and proximal and distal regions of BFs (6±6-8±5%). T2 values substantially increased after hip-extension conic-pulley only in proximal and middle regions of BFl (11±5-7±5%) and ST (7±3-12±4%). The relevance of such MRI-based inter- and intra-muscle use in designing more effective resistance training for improving hamstring function and preventing hamstring injuries in elite soccer players should be explored with more mechanistic studies.

  8. MRI-Based Regional Muscle Use during Hamstring Strengthening Exercises in Elite Soccer Players

    PubMed Central

    Mendez-Villanueva, Alberto; Suarez-Arrones, Luis; Rodas, Gil; Fernandez-Gonzalo, Rodrigo; Tesch, Per; Linnehan, Richard; Kreider, Richard; Di Salvo, Valter

    2016-01-01

    The present study examined site-specific hamstring muscles use with functional magnetic resonance imaging (MRI) in elite soccer players during strength training. Thirty-six players were randomized into four groups, each performing either Nordic hamstring, flywheel leg-curl, Russian belt or the hip-extension conic-pulley exercise. The transverse relaxation time (T2) shift from pre- to post-MRI were calculated for the biceps femoris long (BFl) and short (BFs) heads, semitendinosus (ST) and semimembranosus (SM) muscles at proximal, middle and distal areas of the muscle length. T2 values increased substantially after flywheel leg-curl in all regions of the BFl (from 9±8 to 16±8%), BFs (41±6–71±11%), and ST (60±1–69±7%). Nordic hamstring induced a substantial T2 increase in all regions of the BFs (13±8–16±5%) and ST (15±7–17±5%). T2 values after the Russian belt deadlift substantially increased in all regions of the BFl (6±4–7±5%), ST (8±3–11±2%), SM (6±4–10±4%), and proximal and distal regions of BFs (6±6–8±5%). T2 values substantially increased after hip-extension conic-pulley only in proximal and middle regions of BFl (11±5–7±5%) and ST (7±3–12±4%). The relevance of such MRI-based inter- and intra-muscle use in designing more effective resistance training for improving hamstring function and preventing hamstring injuries in elite soccer players should be explored with more mechanistic studies. PMID:27583444

  9. Inflationary tensor perturbations after BICEP2.

    PubMed

    Caligiuri, Jerod; Kosowsky, Arthur

    2014-05-16

    The measurement of B-mode polarization of the cosmic microwave background at large angular scales by the BICEP experiment suggests a stochastic gravitational wave background from early-Universe inflation with a surprisingly large amplitude. The power spectrum of these tensor perturbations can be probed both with further measurements of the microwave background polarization at smaller scales and also directly via interferometry in space. We show that sufficiently sensitive high-resolution B-mode measurements will ultimately have the ability to test the inflationary consistency relation between the amplitude and spectrum of the tensor perturbations, confirming their inflationary origin. Additionally, a precise B-mode measurement of the tensor spectrum will predict the tensor amplitude on solar system scales to 20% accuracy for an exact power-law tensor spectrum, so a direct detection will then measure the running of the tensor spectral index to high precision.

  10. BICEP2 in corpuscular description of inflation

    SciTech Connect

    Dvali, G.; Gomez, C.

    2015-03-15

    A corpuscular quantum description of inflation shows that there is no fundamental problem with trans-Planckian excursions of the inflaton field up to about 100 Planck masses, with the upper bound coming from the corpuscular quantum effects. In this description, the r parameter measures the ratio of occupation numbers of gravitons versus inflatons, which, according to BICEP2, was roughly a half at the time of 60 e-foldings prior to the end of inflation. We stress that in a non-Wilsonian UV self-completion of gravity, any trans-Planckian mode coupled to the inflaton is a black hole. Unlike the Wilsonian case, integrating them out gives an exponentially suppressed effect and is unable to prevent trans-Planckian excursions of the inflaton field.

  11. Inflationary tensor perturbations after BICEP2.

    PubMed

    Caligiuri, Jerod; Kosowsky, Arthur

    2014-05-16

    The measurement of B-mode polarization of the cosmic microwave background at large angular scales by the BICEP experiment suggests a stochastic gravitational wave background from early-Universe inflation with a surprisingly large amplitude. The power spectrum of these tensor perturbations can be probed both with further measurements of the microwave background polarization at smaller scales and also directly via interferometry in space. We show that sufficiently sensitive high-resolution B-mode measurements will ultimately have the ability to test the inflationary consistency relation between the amplitude and spectrum of the tensor perturbations, confirming their inflationary origin. Additionally, a precise B-mode measurement of the tensor spectrum will predict the tensor amplitude on solar system scales to 20% accuracy for an exact power-law tensor spectrum, so a direct detection will then measure the running of the tensor spectral index to high precision. PMID:24877926

  12. Strength Training to Contraction Failure Increases Voluntary Activation of the Quadriceps Muscle Shortly After Total Knee Arthroplasty

    PubMed Central

    Mikkelsen, Elin Karin; Jakobsen, Thomas Linding; Holsgaard-Larsen, Anders; Andersen, Lars Louis; Bandholm, Thomas

    2016-01-01

    ABSTRACT Objective The objective of this study was to investigate voluntary activation of the quadriceps muscle during one set of knee extensions performed until contraction failure in patients shortly after total knee arthroplasty. Design This was a cross-sectional study of 24 patients with total knee arthroplasty. One set of knee extensions was performed until contraction failure, using a predetermined 10 repetition maximum loading. In the operated leg, electromyographic (EMG) activity of the lateral and medial vastus, semitendinosus, and biceps femoris muscles was recorded during the set. Muscle activity (%EMGmax) and median power frequency of the EMG power spectrum were calculated for each repetition decile (10%–100% contraction failure). Results Muscle activity increased significantly over contractions from a mean of 90.0 and 93.6 %EMGmax (lateral vastus and medial vastus, respectively) at 10% contraction failure to 99.3 and 105.5 %EMGmax at 100% contraction failure (P = 0.009 and 0.004). Median power frequency decreased significantly over contractions from a mean of 66.8 and 64.2 Hz (lateral vastus and medial vastus, respectively) at 10% contraction failure to 59.9 and 60.1 Hz at 100% contraction failure (P = 0.0006 and 0.0187). Conclusion In patients shortly after total knee arthroplasty, 10 repetition maximum–loaded knee extensions performed in one set until contraction failure increases voluntary activation of the quadriceps muscle during the set. Clinical Trials Gov-identifier: NCT01713140 to the abstract to increase trial transparency. PMID:26339729

  13. Intensity of activation and timing of deactivation modulate elastic energy storage and release in a pennate muscle and account for gait-specific initiation of limb protraction in the horse.

    PubMed

    Lichtwark, Glen A; Watson, Johanna C; Mavrommatis, Sophia; Wilson, Alan M

    2009-08-01

    The equine biceps brachii (biceps) initiates rapid limb protraction through a catapult mechanism. Elastic strain energy is slowly stored in an internal tendon and is then rapidly released to protract the forelimb. The muscle fibres are short, have little scope for length change and can therefore only shorten slowly compared with the speed at which the whole muscle must shorten, which makes them poor candidates for driving rapid limb protraction. We suggest that the muscle fibres in the biceps act to modulate the elastic energy output of the muscle-tendon unit (MTU) to meet the demands of locomotion under different conditions. We hypothesise that more elastic strain energy is stored and released from the biceps MTU during higher speed locomotion to accommodate the increase in energy required to protract the limb and that this can be achieved by varying the length change and activation conditions of the muscle. We examined the work performed by the biceps during trot and canter using an inverse dynamics analysis (IDA). We then used excised biceps muscles to determine how much work could be performed by the muscle in active and passive stretch-shorten cycles. A muscle model was developed to investigate the influence of changes in activation parameters on energy storage and energy return from the biceps MTU. Increased biceps MTU length change and increased work performed by the biceps MTU were found at canter compared with at trot. More work was performed by the ex vivo biceps MTU following activation of the muscle and by increasing muscle length change. However, the ratio of active to passive work diminished with increasing length change. The muscle model demonstrated that duration and timing of activation during stretch-shorten cycles could modulate the elastic energy storage and return from the biceps. We conclude that the equine biceps MTU acts as a tuneable spring and the contractile component functions to modulate the energy required for rapid forelimb

  14. The impact of ergometer design on hip and trunk muscle activity patterns in elite rowers: an electromyographic assessment.

    PubMed

    Nowicky, Alex V; Horne, Sara; Burdett, Richard

    2005-03-01

    THIS STUDY USED SURFACE ELECTROMYOGRAPHY (SEMG) TO EXAMINE WHETHER THERE WERE DIFFERENCES IN HIP AND TRUNK MUSCLE ACTIVATION DURING THE ROWING CYCLE ON TWO OF THE MOST WIDELY USED AIR BRAKED ERGOMETERS: the Concept 2C and the Rowperfect. sEMG methods were used to record the muscle activity patterns from the right: m. Erector spinae (ES), m. Rectus Abdominus (RA), m. Rectus Femoris (RF) and m. Biceps Femoris (BF) for their contributions as agonist-antagonist pairs underlying hip and trunk extension/flexion. The sEMG activity patterns of these muscles were examined in six young male elite rowers completing a 2 minute set at a moderate training intensity (23 stroke·min(-1) and 1:47.500 m(-1) split time, 300W). The rowers closely maintained the required target pace through visual inspection of the standard LCD display of each ergometer. The measurements of duration of each rowing cycle and onset of each stroke during the test were recorded simultaneously with the sEMG activity through the additional instrumentation of a foot-pressure switch and handle accelerometry. There were no significant differences between the two ergometer designs in group means for: work rate (i.e., rowing speed and stroke rate), metabolic load as measured by mean heart rate, rowing cycle duration, or timing of the stroke in the cycle. 2-D motion analysis of hip and knee motion for the rowing cycle from the video footage taken during the test also revealed no significant differences in the joint range of motion between the ergometers. Ensemble average sEMG activity profiles based on 30+ strokes were obtained for each participant and normalised per 10% intervals of the cycle duration as well as for peak mean sEMG amplitude for each muscle. A repeated measures ANOVA on the sEMG activity per 10% interval for the four muscles contributing to hip and trunk motion during the rowing cycle revealed no significant differences between the Concept 2C and Rowperfect (F = 0.070, df = 1,5, p = 0.802). The

  15. The effect of knee brace on coordination and neuronal leg muscle control: an early postoperative functional study in anterior cruciate ligament reconstructed patients.

    PubMed

    Rebel, M; Paessler, H H

    2001-09-01

    Two studies were carried out after anterior cruciate ligament (ACL) reconstruction to determine the effect of a knee brace on coordination (test 1) and electromyographic muscle activity in drop jumps (test 2). Test 1 studied 25 patients with ACL reconstruction under three test conditions (one-leg static, two-legged static, two-legged dynamic) compared with a control (n=30). The results showed highly significant improvements in all braced conditions. In test 2 ten patients with ACL reconstruction and ten healthy subjects performed a two-legged drop-jump; this was repeated 15 times and again 15 times with a knee brace worn on the reconstructed limb. Changes in electromyographically determined muscle activity (vastus medialis, vastus lateralis, biceps femoris, gastrocnemius) were observed, but they were significant in only few cases because of high variability. Drop-jumps with knee brace improved jumping height, increased the maximum knee angle in the ground contact phase, and reduced the maximum knee angle in the landing phase. Patients thus develop an increased confidence in the stability of their knees. We conclude that the benefits of the knee brace are due to the mechanical action, an enhanced coordination, and a psychological effect.

  16. Adaptive control for backward quadrupedal walking V. Mutable activation of bifunctional thigh muscles.

    PubMed

    Pratt, C A; Buford, J A; Smith, J L

    1996-02-01

    1. In this, the fifth article in a series to assess changes in posture, hindlimb dynamics, and muscle synergies associated with backward (BWD) quadrupedal walking, we compared the recruitment of three biarticular muscles of the cat's anterior thigh (anterior sartorius, SAa; medial sartorius, SAm; rectus femoris, RF) for forward (FWD) and BWD treadmill walking. Electromyography (EMG) records from these muscles, along with those of two muscles (semitendinosus, ST; anterior biceps femoris, ABF) studied previously in this series, were synchronized with kinematic data digitized from high-speed ciné film for unperturbed steps and steps in which a stumbling corrective reaction was elicited during swing. 2. During swing, the relative timing of EMG activity for the unifunctional SAm (hip and knee flexor) was similar for unperturbed steps of FWD and BWD walking. The SAm was active before paw lift off and remained active during most of swing (75%) for both forms of walking, but there was a marked decrease in EMG amplitude after paw off during BWD and not FWD swing. In contrast, the relative timing of EMG activity for the SAa and RF, two bifunctional muscles (hip flexors, knee extensors), was different for FWD and BWD swing. During FWD swing, the SAa and the RF (to a lesser extent) were coactive with the SAm; however, during BWD swing, the SAa and RF were active just before paw lift off and then inactive for the rest of swing until just before paw contact (see 3). Thus the swing-phase activity of the SAa and RF was markedly shorter for BWD than FWD swing. 3. Activity in SAa and RF was also different during FWD and BWD stance. The RF was consistently active from mid-to-late stance of FWD walking, and the SAa was also active during this period in some FWD steps. During the stance phase of BWD walking, however, the onset of activity in both muscles consistently shifted to early stance as both muscles became active just before paw contact (the E1 phase). Activity in RF

  17. Variation in palatability and biochemical traits within and among eleven beef muscles.

    PubMed

    Rhee, M S; Wheeler, T L; Shackelford, S D; Koohmaraie, M

    2004-02-01

    The objective of this study was to determine the extent of variation in, and relationships among, biochemical and palatability traits within and among 11 major beef muscles. Longissimus thoracis et lumborum (LD), psoas major (PM), gluteus medius (GM), semimembranosus (SM), adductor (AD), biceps femoris (BF), semitendinosus (ST), rectus femoris (RF), triceps brachii (TB), infraspinatus (IS), and supraspinatus (SS) from one side of 31 Charolais x MARC III steer carcasses were vacuum-packaged, stored at 2 degrees C until 14 d postmortem, and then frozen at -30 degrees C. The 2.54-cm-thick steaks were obtained from two or three locations within muscles in order to assess biochemical traits and Warner-Bratzler shear force, and from near the center for sensory trait evaluation. The PM was most tender and was followed by IS in both shear force and tenderness rating (P < 0.05). The other muscles were not ranked the same by shear force and tenderness rating. The BF had the lowest (P < 0.05) tenderness rating. The PM, GM, and LD had lower (P < 0.05) collagen concentration (2.7 to 4.5 mg/g muscle) than muscles from the chuck and round (5.9 to 9.0 mg/g), except for the AD (4.9 mg/g). Desmin proteolysis was highest (P < 0.05) for BF and LD (60.7 and 60.1% degraded), and was lowest (P < 0.05) for PM (20.2%). The PM, TB, IS, RF, and ST had relatively long sarcomere lengths (> 2.1 microm), whereas the GM had the shortest (P < 0.05) sarcomere length (1.7 microm). Cooking loss was lowest (P < 0.05) for BF (18.7%) and was followed by LD and IS (20.7%); it was highest (P < 0.05) for ST (27.4%). Across all muscles, tenderness rating was highly correlated (r > 0.60) with shear force, connective tissue rating, sarcomere length, and collagen content. Within a muscle, correlations among all traits were generally highest in LD and lowest in AD. Within muscle, location effects were detected (P < 0.05) for shear force (PM, ST, BF, SM, and RF), sarcomere length (PM, ST, BF, LD, SS, IS, SM, and

  18. Effects of prolonged patellar tendon vibration on force steadiness in quadriceps femoris during force-matching task.

    PubMed

    Saito, Akira; Ando, Ryosuke; Akima, Hiroshi

    2016-01-01

    The quadriceps femoris (QF) muscle group plays an essential role in human movement, such as standing, walking and running. The ability to maintain a steady force during physical activity of the human lower limb is important for mobility, postural control and balance. Although prolonged mechanical vibration of the muscle-tendon unit can moderate the efficacy of synaptic input from Ia afferent onto the α-motor neuron pathway, the effect of prolonged tendon vibration on fluctuations of knee extensor force has received little attention. The purpose of the present study was to examine the effects of prolonged patellar tendon vibration on the force steadiness of the QF muscle. Nine healthy men performed a submaximal force-matching task involving isometric knee extension before and after patellar tendon vibration or quiet seated rest (n = 7, control condition) for 30 min. The target force was 2.5, 10 and 30 % of maximal voluntary contraction (MVC). Surface electromyography (EMG) of the four QF synergists was recorded and normalized to EMG amplitude during the MVC. The knee extension force and the EMG amplitude of vastus medialis during the MVC were significantly reduced after the vibration, but did not significantly decrease in the control condition. Fluctuations of force and normalized EMG of individual QF muscles at each submaximal force level did not significantly change after the vibration. We conclude that prolonged patellar tendon vibration does not influence the force steadiness of the QF muscle during an isometric force-matching task.

  19. Profunda Femoris Pseudoaneurysm following Total Hip Arthroplasty Revision

    PubMed Central

    Harper, Katharine; Iorio, Justin; Balasubramanian, Easwaran

    2015-01-01

    Vascular injuries following total hip arthroplasty (THA) are very rare, with pseudoaneurysm being a small subset. We report a case of profunda femoris artery (PFA) pseudoaneurysm in a 61-year-old male following a posterior approach revision left THA. Presentation involved continued blood transfusion requirements several weeks postoperatively. Diagnosis of the pseduoaneurysm was made by contrast CT of the lower extremity, with confirmation via IR angiography. Successful embolization was achieved with selective coiling and Gelfoam. Presenting complaints of such complications are often vague and therefore lead to delayed diagnosis. Causes of such complications are not completely understood, particularly with PFA injuries in THA. Possible mechanisms are discussed in this paper. Vascular complications following THA can be difficult to diagnose. High suspicion in the setting of continued postoperative pain or bleeding may allow prompt diagnosis and avoidance of serious limb-threatening complications. PMID:26347839

  20. Biochemical measurements of beef are a good predictor of untrained consumer sensory scores across muscles.

    PubMed

    Bonny, S P F; Gardner, G E; Pethick, D W; Legrand, I; Polkinghorne, R J; Hocquette, J F

    2015-01-01

    The ability of the biochemical measurements, haem iron, intramuscular fat (IMF%), moisture content, and total, soluble and insoluble collagen contents, to predict untrained consumer sensory scores both across different muscles and within the same muscle from different carcasses were investigated. Sensory scores from 540 untrained French consumers (tenderness, flavour liking, juiciness and overall liking) were obtained for six muscles; outside (m. biceps femoris), topside (m. semimembranosus), striploin (m. longissimus thoracis), rump (m. gluteus medius), oyster blade (m. infraspinatus) and tenderloin (m. psoas major) from each of 18 French and 18 Australian cattle. The four sensory scores were weighted and combined into a single score termed MQ4, which was also analysed. All sensory scores were highly correlated with each other and with MQ4. This in part reflects the fact that MQ4 is derived from the consumer scores for tenderness, juiciness, flavour and overall liking and also reflects an interrelationship between the sensory scores themselves and in turn validates the use of the MQ4 term to reflect the scope of the consumer eating experience. When evaluated across the six different muscles, all biochemical measurements, except soluble collagen, had a significant effect on all of the sensory scores and MQ4. The average magnitude of impact of IMF%, haem iron, moisture content, total and insoluble collagen contents across the four different sensory scores are 34.9, 5.1, 7.2, 36.3 and 41.3, respectively. When evaluated within the same muscle, only IMF% and moisture content had a significant effect on overall liking (5.9 and 6.2, respectively) and flavour liking (6.1 and 6.4, respectively). These results indicate that in a commercial eating quality prediction model including muscle type, only IMF% or moisture content has the capacity to add any precision. However, all tested biochemical measurements, particularly IMF% and insoluble collagen contents, are strong

  1. Leg and trunk muscle coordination and postural sway during increasingly difficult standing balance tasks in young and older adults.

    PubMed

    Donath, Lars; Kurz, Eduard; Roth, Ralf; Zahner, Lukas; Faude, Oliver

    2016-09-01

    Ageing impairs body balance and increases older adults' fall risk. Balance training can improve intrinsic fall risk factors. However, age comparisons of muscle activity responses during balance tasks are lacking. This study investigated relative muscle activity, muscle coordination and postural sway during various recommended static balance training tasks. Muscle activity (%MVC), amplitude ratios (AR) and co-activity (CAI) were determined during standing tasks for 30s (1: double limb stance on a foam surface, eyes open; 2: double limb stance on firm ground, eyes closed; 3: double limb stance, feet in step position on a foam surface, eyes open; 4: double limb stance, feet in step position on firm ground, eyes closed; 5: single limb stance on firm ground, eyes open) in 20 healthy young adults (24±2 y) and 20 older adults (73±6 y). Surface electromyography (SEMG) was applied (SENIAM guidelines) to ankle (tibialis anterior, soleus, medial gastrocnemius, peroneus longus) and thigh (vastus lateralis, vastus medialis, biceps femoris, semitendinosus) muscles (non-dominant leg). Electrodes over trunk (multifidus and internal oblique) muscles were applied bilaterally. Two- to six-fold higher levels of relative muscle activity were found in older adults for ankle (0.0002muscles. Co-activation was elevated in young adults for the trunk (0.001muscle coordination patterns during all stance conditions at the ankle (0.06<ηp(2)<0.28) and the trunk (0.14<ηp(2)<0.23). Older adults had higher electrophysiological costs for all stance conditions. Muscle coordination showed inverse activity patterns at the ankle and trunk. Optimal balance and strength training programs should take into account age-specific alterations in muscle activity. PMID:27451322

  2. Hamstring muscle strain treated by mobilizing the sacroiliac joint.

    PubMed

    Cibulka, M T; Rose, S J; Delitto, A; Sinacore, D R

    1986-08-01

    The purpose of this study was to compare the effectiveness of two types of treatment of hamstring muscle strains. Twenty patients with hamstring muscle strains were assigned randomly to an Experimental Group (n = 10) or a Control Group (n = 10). Peak torque production of the quadriceps femoris and hamstring muscles and hamstring muscle length were measured before and after treatment. The hamstring muscles of the Experimental and Control groups were treated with moist heat followed by passive stretching. The Experimental Group also received manipulation of the sacroiliac joint. The change in hamstring muscle peak torque was significantly greater for the Experimental Group than for the Control Group (p less than .005). No significant differences existed between the two groups in either quadriceps femoris muscle peak torque or hamstring muscle length. The results of this study suggest a relationship between sacroiliac joint dysfunction and hamstring muscle strain.

  3. Muscle Contraction Velocity: A Suitable Approach to Analyze the Functional Adaptations in Elite Soccer Players

    PubMed Central

    Loturco, Irineu; Pereira, Lucas A.; Kobal, Ronaldo; Kitamura, Katia; Ramírez-Campillo, Rodrigo; Zanetti, Vinicius; Abad, Cesar C. Cal; Nakamura, Fabio Y.

    2016-01-01

    Tensiomyography (TMG) has been used as a simple and non-invasive tool to assess the mechanical properties of skeletal muscles. The TMG-derived velocity of contraction (Vc), which can be calculated from the ratio between maximal radial displacement and the sum of contraction time and delay time, has been proposed for evaluating athletes. However, its sensitivity to training effects and possible relation with changes in soccer players’ neuromuscular performance have not yet been addressed. To test this possibility, twenty-two male Brazilian elite soccer players were assessed using TMG-derived Vc, unloaded squat jump, countermovement jump and drop jump at 45 cm, loaded jump squat and linear (20 m) and change of direction (COD) sprint tests, prior to and after an 8-week period, between two consecutive official tournaments, during which the concurrency between endurance and strength-power training commonly impairs neuromuscular capacities. Magnitude-based inference was used to detect meaningful training effects. From pre- to post-tests, it was observed likely to almost certainly improvements in all modes of jumping tests. In addition, we could verify decrements in the 20-m and COD sprint performances, which were rated as very likely and almost certainly, respectively. Finally, both rectus femoris and biceps femoris muscles presented a likely reduction in Vc. Therefore, chronic decreases in sprinting speed are possibly accompanied by a reduced TMG-derived Vc. From a practical standpoint, the TMG-derived Vc can be used to monitor negative specific-soccer training effects related to potential impairments in maximum speed. Key points Tensiomyography (TMG) can be considered a useful technology for coaches and sport scientists seeking for non-invasive and practical tools to assess the muscle function of elite athletes; Velocity of contraction (Vc) is a single index able to integrate several of the reliable mechanical outcomes provided by TMG, which was shown to be sensitive

  4. 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

  5. Selection of reference genes for gene expression studies related to intramuscular fat deposition in Capra hircus skeletal muscle.

    PubMed

    Zhu, Wuzheng; Lin, Yaqiu; Liao, Honghai; Wang, Yong

    2015-01-01

    The identification of suitable reference genes is critical for obtaining reliable results from gene expression studies using quantitative real-time PCR (qPCR) because the expression of reference genes may vary considerably under different experimental conditions. In most cases, however, commonly used reference genes are employed in data normalization without proper validation, which may lead to incorrect data interpretation. Here, we aim to select a set of optimal reference genes for the accurate normalization of gene expression associated with intramuscular fat (IMF) deposition during development. In the present study, eight reference genes (PPIB, HMBS, RPLP0, B2M, YWHAZ, 18S, GAPDH and ACTB) were evaluated by three different algorithms (geNorm, NormFinder and BestKeeper) in two types of muscle tissues (longissimus dorsi muscle and biceps femoris muscle) across different developmental stages. All three algorithms gave similar results. PPIB and HMBS were identified as the most stable reference genes, while the commonly used reference genes 18S and GAPDH were the most variably expressed, with expression varying dramatically across different developmental stages. Furthermore, to reveal the crucial role of appropriate reference genes in obtaining a reliable result, analysis of PPARG expression was performed by normalization to the most and the least stable reference genes. The relative expression levels of PPARG normalized to the most stable reference genes greatly differed from those normalized to the least stable one. Therefore, evaluation of reference genes must be performed for a given experimental condition before the reference genes are used. PPIB and HMBS are the optimal reference genes for analysis of gene expression associated with IMF deposition in skeletal muscle during development.

  6. BICEP2, the curvature perturbation and supersymmetry

    SciTech Connect

    Lyth, David H.

    2014-11-01

    The tensor fraction r ≅ 0.16 found by BICEP2 corresponds to a Hubble parameter H ≅ 1.0 × 10{sup 14} GeV during inflation. This has two implications for the (single-field) slow-roll inflation hypothesis. First, the inflaton perturbation must account for much more than 10% of the curvature perturbation ζ, which barring fine-tuning means that it accounts for practically all of it. It follows that a curvaton-like mechanism for generating ζ requires an alternative to slow roll such as k-inflation. Second, accepting slow-roll inflation, the excursion of the inflaton field is at least of order Planck scale. As a result, the flatness of the inflaton presumably requires a shift symmetry. I point out that if such is the case, the resulting potential is likely to have at least approximately the quadratic form suggested in 1983 by Linde, which is known to be compatible with the observed r as well as the observed spectral index n{sub s}. The shift symmetry does not require supersymmetry. Also, the big H may rule out a GUT by restoring the symmetry and producing fatal cosmic strings. The absence of a GUT would correspond to the absence of superpartners for the Standard Model particles, which indeed have yet to be found at the LHC.

  7. The Effect of Monochromatic Infrared Photo Energy on the Irritability of Myofascial Trigger Spot of Rabbit Skeletal Muscle

    PubMed Central

    Kuan, Ta-Shen; Lin, Yu-Ching; Lien, Wei-Chih; Hsieh, Pei-Chun; Chung, Yu-Ting; Lin, Sheng-Hsiang; Chou, Li-Wei

    2015-01-01

    Objective. To determine whether the vasodilatation effect of monochromatic infrared photo energy (MIRE) had the potential for the treatment of myofascial trigger spot (MTrS) in rabbits. Design. A randomized-controlled animal study. Subjects. Twelve adult New Zealand rabbits. Methods. For each rabbit, a MTrS (equivalent to a myofascial trigger point in humans) in one side of the biceps femoris muscle was randomly selected for MIRE treatment (experimental side), while another MTrS in the other side (control side) received a sham treatment. The intervention consisted of a daily 40 minutes treatment, three times per week for 2 weeks. The prevalence of endplate noise (EPN) loci in the MTrS was assessed before, immediately after, and one week after the completion of the 2-week treatment. Results. MIRE could suppress the prevalence of EPN in the MTrS. The degree of reduction in EPN prevalence in the MTrS between the experimental side and the control side was significantly different immediately after MIRE treatment, but not significantly different one week after MIRE treatment. Conclusion. Our study suggests that MIRE may be a useful therapeutic option for the management of the myofascial trigger point in humans. PMID:26442122

  8. Selective contribution of each hamstring muscle to anterior cruciate ligament protection and tibiofemoral joint stability in leg-extension exercise: a simulation study.

    PubMed

    Biscarini, Andrea; Botti, Fabio Massimo; Pettorossi, Vito Enrico

    2013-09-01

    A biomechanical model was developed to simulate the selective effect of the co-contraction force provided by each hamstring muscle on the shear and compressive tibiofemoral joint reaction forces, during open kinetic-chain knee-extension exercises. This model accounts for instantaneous values of knee flexion angle [Formula: see text], angular velocity and acceleration, and for changes in magnitude, orientation, and application point of external resistance. The tibiofemoral shear force (TFSF) largely determines the tensile force on anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). Biceps femoris is the most effective hamstring muscle in decreasing the ACL-loading TFSF developed by quadriceps contractions for [Formula: see text]. In this range, the semimembranosus generates the dominant tibiofemoral compressive force, which enhances joint stability, opposes anterior/posterior tibial translations, and protects cruciate ligaments. The semitendinosus force provides the greatest decreasing gradient of ACL-loading TFSF for [Formula: see text], and the greatest increasing gradient of tibiofemoral compressive force for [Formula: see text]. However, semitendinosus efficacy is strongly limited by its small physiological section. Hamstring muscles behave as a unique muscle in enhancing the PCL-loading TFSF produced by quadriceps contractions for [Formula: see text]. The levels of hamstrings co-activation that suppress the ACL-loading TFSF considerably shift when the knee angular acceleration is changed while maintaining the same level of knee extensor torque by a concurrent adjustment in the magnitude of external resistance. The knowledge of the specific role and the optimal activation level of each hamstring muscle in ACL protection and tibiofemoral stability are fundamental for planning safe and effective rehabilitative knee-extension exercises.

  9. Selective contribution of each hamstring muscle to anterior cruciate ligament protection and tibiofemoral joint stability in leg-extension exercise: a simulation study.

    PubMed

    Biscarini, Andrea; Botti, Fabio Massimo; Pettorossi, Vito Enrico

    2013-09-01

    A biomechanical model was developed to simulate the selective effect of the co-contraction force provided by each hamstring muscle on the shear and compressive tibiofemoral joint reaction forces, during open kinetic-chain knee-extension exercises. This model accounts for instantaneous values of knee flexion angle [Formula: see text], angular velocity and acceleration, and for changes in magnitude, orientation, and application point of external resistance. The tibiofemoral shear force (TFSF) largely determines the tensile force on anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). Biceps femoris is the most effective hamstring muscle in decreasing the ACL-loading TFSF developed by quadriceps contractions for [Formula: see text]. In this range, the semimembranosus generates the dominant tibiofemoral compressive force, which enhances joint stability, opposes anterior/posterior tibial translations, and protects cruciate ligaments. The semitendinosus force provides the greatest decreasing gradient of ACL-loading TFSF for [Formula: see text], and the greatest increasing gradient of tibiofemoral compressive force for [Formula: see text]. However, semitendinosus efficacy is strongly limited by its small physiological section. Hamstring muscles behave as a unique muscle in enhancing the PCL-loading TFSF produced by quadriceps contractions for [Formula: see text]. The levels of hamstrings co-activation that suppress the ACL-loading TFSF considerably shift when the knee angular acceleration is changed while maintaining the same level of knee extensor torque by a concurrent adjustment in the magnitude of external resistance. The knowledge of the specific role and the optimal activation level of each hamstring muscle in ACL protection and tibiofemoral stability are fundamental for planning safe and effective rehabilitative knee-extension exercises. PMID:23670482

  10. The comparison of wavelet- and Fourier-based electromyographic indices of back muscle fatigue during dynamic contractions: validity and reliability results.

    PubMed

    da Silva, R A; Larivière, C; Arsenault, A B; Nadeau, S; Plamondon, A

    2008-01-01

    The purpose of this study was to compare the electromyographic (EMG) fatigue indices computed from short-time Fourier transform (STFT) and wavelet transform (WAV), by analyzing their criterion validity and test-retest reliability. The effect of averaging spectral estimates within and between repeated contractions (cycles) on EMG fatigue indices was also demonstrated. Thirty-one healthy subjects performed trunk flexion-extension cycles until exhaustion on a Biodex dynamometer. The load was determined theoretically as twice the L5-S1 moment produced by the trunk mass. To assess reliability, 10 subjects performed the same experimental protocol after a two-week interval. EMG signals were recorded bilaterally with 12 pairs of electrodes placed on the back muscles (at L4, L3, L1 and T10 levels), as well as on the gluteus maximus and biceps femoris. The endurance time and perceived muscle fatigue (Borg CR-10 scale) were used as fatigue criteria. EMG signals were processed using STFT and WAV to extract global (e.g, median frequency and instantaneous median frequency, respectively) or local (e.g., intensity contained in 8 frequency bands) information from the power spectrum. The slope values of these variables over time, obtained from regression analyses, were retained as EMG fatigue indices. EMG fatigue indices (STFT vs. WAV) were not significantly different within each muscle, had a variable association (Pearson's r range.: 0.06 to 0.68) with our fatigue criteria, and showed comparable reliability (Intra-class correlation range: 0.00 to 0.88), although they varied between muscles. The effect of averaging, within and between cycles, contributed to the strong association between EMG fatigue indices computed from STFT and WAV. As for EMG spectral indices of muscle fatigue, the conclusion is that both transforms carry essentially the same information.

  11. Clinico-embryological perspective of a rare accessory brachial muscle with possible musculocutaneous nerve compression.

    PubMed

    Mehta, V; Yadav, Y; Arora, Jyoti; Kumar, H; Suri, R K; Rath, G

    2009-03-01

    Both brachialis and biceps brachii are primary flexors of the arm and elbow from the biomechanical perspective. Numerous reports exist in anatomical literature regarding accessory heads of biceps brachii, although such accessory bellies in relation to brachialis muscle are less frequently elucidated. We report a unilateral case of a rare accessory muscle interposed between the biceps brachii and brachialis, having the musculocutaneous nerve (MCN) entrapped between the two. Furthermore, the muscle divided into two slips, upper slip was attached to biceps brachii and the other gained insertion to the brachial fascia. Innervation to this accessory muscle was derived from MCN. The embryological basis for such supernumerary muscle is discussed. Additionally, the case is considered under surgical and clinical perspective, highlighting the importance of familiarity with such variations. Anatomical variations of the brachial musculature may cause diagnostic perplexities while interpreting MRI or CT scans.

  12. Long head of the biceps pathology as a cause of anterior shoulder pain after shoulder arthroplasty.

    PubMed

    Tuckman, David V; Dines, David M

    2006-01-01

    The use of shoulder arthroplasty has been increasing over the last decade, with nearly 20,000 shoulder arthroplasties being performed each year. Although many patients have excellent results, there exists a subset of patients in whom anterior catching shoulder pain develops after arthroplasty. The purpose of this study was to examine this group of patients and explore treatment options and outcomes for this condition. We undertook a review of 8 shoulders in 7 patients who were treated for anterior shoulder pain radiating into the biceps muscle after shoulder arthroplasty. Three patients had a hemiarthroplasty for fracture, and five had a total shoulder arthroplasty. All patients had anterior shoulder pain with physical examination findings consistent with biceps tendon pathology. Definitive diagnosis and treatment consisted of either arthroscopy, in 7 of 8 shoulders, or an open procedure, in 1 of 8 shoulders. The range of motion improved in all shoulders. The hemiarthroplasty group showed an increase in flexion of 36 degrees (range, 68 degrees -104 degrees ), external rotation of 23 degrees (range, 11 degrees -34 degrees ), and internal rotation to L4. The total shoulder group demonstrated an increase in flexion of 50 degrees (range, 66 degrees -166 degrees ), external rotation of 27 degrees (range, 22 degrees -39 degrees ), and internal rotation to L3. The Hospital for Special Surgery score improved in all shoulders, with all patients being satisfied with their final outcome. Pain scores improved from a mean of 6.9 (range, 4-9) preoperatively to 1.4 (range, 0.5-2) postoperatively on a scale of 1 to 10, with 10 indicating the most pain. The role of the biceps tendon in the pathology of anterior shoulder pain after shoulder arthroplasty appears to be consistent with fibrosis and inflammation. Initial results, achieved with arthroscopic debridement or tenodesis, were encouraging.

  13. Effects of barbell deadlift training on submaximal motor unit firing rates for the vastus lateralis and rectus femoris.

    PubMed

    Stock, Matt S; Thompson, Brennan J

    2014-01-01

    Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC) assessment. Twenty-four previously untrained men (mean age  = 24 years) were randomly assigned to training (n = 15) or control (n = 9) groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC) and y-intercepts (pps) of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70), but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units. PMID:25531294

  14. Effects of Barbell Deadlift Training on Submaximal Motor Unit Firing Rates for the Vastus Lateralis and Rectus Femoris

    PubMed Central

    Stock, Matt S.; Thompson, Brennan J.

    2014-01-01

    Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC) assessment. Twenty-four previously untrained men (mean age  = 24 years) were randomly assigned to training (n = 15) or control (n = 9) groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC) and y-intercepts (pps) of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70), but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units. PMID:25531294

  15. Effect of pH(24h), curing salts and muscle types on the oxidative stability, free amino acids profile and vitamin B2, B3 and B6 content of dry-cured ham.

    PubMed

    Gratacós-Cubarsí, M; Sárraga, C; Castellari, M; Valero, A; García Regueiro, J A; Arnau, J

    2013-12-01

    The effects of a curing salt composition (with and without nitrifying salts), and the pH at 24h postmortem (pH24>6.0, 5.5Biceps femoris (BF) muscles of pork legs for compositional and nutritional attributes at the end of dry-cured ham ageing. The muscles free amino acid profile (FAA) was not influenced by nitrifying salts. The pH24 was the factor which had the greatest consequences on the dry-cured ham characteristics analysed. The increase in nicotinamide and decrease in pyridoxine by curing salts and the decrease in both vitamins by pH24, had no major effect on the nutritional value of the dry-cured ham because the remaining amounts were within the intervals found in the nutritional data base for dry-cured ham. The results obtained suggested a cooperative action of vitamins B3 and B6 and the antioxidant enzyme system against oxidation. Thiobarbituric acid reactive substances (TBARS) were reduced by the addition of curing salts but were low in all cases, suggesting high antioxidant stability in dry-cured ham which was corroborated by the low volatile aldehyde contents.

  16. Behaviour of the electrical impedance myography in isometric contraction of biceps brachii at different elbow joint angles

    NASA Astrophysics Data System (ADS)

    Coutinho, A. B. B.; Jotta, B.; Pino, A. V.; Souza, M. N.

    2012-12-01

    Electrical impedance myography (EIM) can be understood as an experimental technique applied to evaluate bioelectrical impedance associated to the muscular activity. With the development of technique, some studies are trying to associate the EIM parameters with the morphological and physiological changes that occur in the muscle during contraction. In this context this work sought to associate EIM parameters observed during isometric contractions of the biceps brachii muscle at different elbow joint angles with the correspondent muscular force. Differently from previous works that did not observe significant correlation between those data, our findings point to high correlations between the some EIM resistive parameters and the muscle force. Despite the need of further investigation, our results indicated that EIM technique can be used to estimate muscle force in a noninvasive way.

  17. bicep2/KECK ARRAY. IV. OPTICAL CHARACTERIZATION AND PERFORMANCE OF THE bicep2 AND KECK ARRAY EXPERIMENTS

    SciTech Connect

    Ade, P. A. R.; Aikin, R. W.; Bock, J. J.; Brevik, J. A.; Filippini, J. P.; Golwala, S. R.; Hildebrandt, S. R.; Hui, H.; Barkats, D.; Benton, S. J.; Bischoff, C. A.; Bradford, K. J.; Buder, I.; Bullock, E.; Dowell, C. D.; Duband, L.; Fliescher, S.; Halpern, M.; Hasselfield, M.; Hilton, G. C.; Collaboration: bicep2 and Keck Array Collaborations; and others

    2015-06-20

    bicep2 and the Keck Array are polarization-sensitive microwave telescopes that observe the cosmic microwave background (CMB) from the South Pole at degree angular scales in search of a signature of inflation imprinted as B-mode polarization in the CMB. bicep2 was deployed in late 2009, observed for three years until the end of 2012 at 150 GHz with 512 antenna-coupled transition edge sensor bolometers, and has reported a detection of B-mode polarization on degree angular scales. The Keck Array was first deployed in late 2010 and will observe through 2016 with five receivers at several frequencies (95, 150, and 220 GHz). bicep2 and the Keck Array share a common optical design and employ the field-proven bicep1 strategy of using small-aperture, cold, on-axis refractive optics, providing excellent control of systematics while maintaining a large field of view. This design allows for full characterization of far-field optical performance using microwave sources on the ground. Here we describe the optical design of both instruments and report a full characterization of the optical performance and beams of bicep2 and the Keck Array at 150 GHz.

  18. Effect of muscle and intensity of finishing diet on meat quality of foals slaughtered at 15 months.

    PubMed

    Franco, Daniel; Lorenzo, José M

    2014-01-01

    The effect of muscle and intensity of finishing diet on meat quality of foals slaughtered at 15 months was study. For this work, a total of twenty one foals and six muscles: longissimus dorsi (LD), semimembranosus (SM), semitendinosus (ST), biceps femoris (BF), triceps brachii (TB) and Psoas major & minor (PM) from two different intensities of finishing diet (1.5 vs. 3 kg/day) were analysed. Meat quality (chemical composition, colour characteristics, and textural traits), fatty and amino acid profile and mineral composition were studied. In general the factor muscle had more effect on all traits measured in this study than finishing effect, especially in the fatty acids and mineral composition. SM muscle showed the highest percentage of protein in both finishing groups (22.34 and 21.74% for 3 and 1.5 kg of commercial feeding, respectively). The intramuscular fat content in the analysed muscles ranged between 0.15% (LD in 1.5 group) and 1.83% (PM in 3.0 group). The highest values of iron heme that were obtained in TB muscle (2.46 mg/100 g meat) are a considerable source of bioavailable iron content. The three most abundant fatty acids in both groups and for all muscles studied were oleic acid, palmitoleic acid and linoleic acid. From a healthy point of view, muscles from foals finishing with a minor amount of commercial fodder were the best. The best nutritional value was reached for PM and ST with 14.73% of total omega 3 and the highest polyunsaturated/saturated ratio (1.10), respectively. Concerning amino acid profile, values of essential/non-essential ratio were significantly higher (P<0.001) in muscles of 1.5 diet group foals (0.856) than the other group (0.833). Finally, potassium (243 mg/100 g) and phosphorous (202 mg/100 g) were the two main minerals, followed by sodium (54 mg/100 g) and magnesium (26 mg/100 g).

  19. Muscle characteristics and meat quality traits are affected by divergent selection on residual feed intake in pigs.

    PubMed

    Lefaucheur, L; Lebret, B; Ecolan, P; Louveau, I; Damon, M; Prunier, A; Billon, Y; Sellier, P; Gilbert, H

    2011-04-01

    Residual feed intake (RFI) is defined as the difference between the observed feed intake and that expected based on requirements for maintenance and production. A divergent selection was conducted during 4 generations in Large White male pigs to produce low and high RFI lines. The present study aims at determining the influence of this selection on biochemical and histological traits of skeletal muscle, and relating these changes to correlated effects on growth, carcass composition, and meat quality traits. At 8 d preslaughter, biopsies from the LM were taken in the fed state on 14 females from each RFI line fed ad libitum. Animals were slaughtered at 107.8 ± 8.0 kg of BW without any previous fasting. Samples of LM, semimembranosus (SM), biceps femoris (BFM), and rhomboideus muscles were taken at both 30 min and 24 h postmortem. Myofiber typing was only assessed in LM. Low RFI pigs ("efficient") had leaner carcasses with greater muscle content (P < 0.001), less backfat thickness (P < 0.001), and less intramuscular fat content in all 4 muscles (P < 0.01 to P = 0.04). Their greater muscle content was associated with hypertrophy of all fast-twitch fibers. Glycogen content in all glycolytic muscles (i.e., LM, SM and BFM), was greater in low than high RFI pigs. The greater accumulation of glycogen in LM of low RFI pigs was specifically located in the fast-twitch glycolytic IIBW fibers, which correspond to fibers containing IIb, IIb + IIx, or IIx myosin heavy chains. The difference in muscle glycogen content between RFI line pigs was more significant in the living animals (P = 0.0003) than at 30 min postmortem (P = 0.08). This was associated with a decreased ultimate pH (P = 0.001), and greater lightness of color (P = 0.002) and drip loss (P = 0.04) in LM of low than high RFI line pigs, suggesting that selection for reduced RFI may impair some meat quality traits, such as water-holding capacity. Pigs from the low RFI line exhibited a greater (P = 0.02) percentage of

  20. BICEP2. II. Experiment and three-year data set

    SciTech Connect

    Ade, P. A. R.; Aikin, R. W.; Bock, J. J.; Brevik, J. A.; Filippini, J. P.; Golwala, S. R.; Hildebrandt, S. R.; Amiri, M.; Davis, G.; Halpern, M.; Hasselfield, M.; Barkats, D.; Benton, S. J.; Bischoff, C. A.; Buder, I.; Bullock, E.; Day, P. K.; Dowell, C. D.; Duband, L.; Fliescher, S.; Collaboration: Bicep2 Collaboration; and others

    2014-09-01

    We report on the design and performance of the BICEP2 instrument and on its three-year data set. BICEP2 was designed to measure the polarization of the cosmic microwave background (CMB) on angular scales of 1°-5°(ℓ = 40-200), near the expected peak of the B-mode polarization signature of primordial gravitational waves from cosmic inflation. Measuring B-modes requires dramatic improvements in sensitivity combined with exquisite control of systematics. The BICEP2 telescope observed from the South Pole with a 26 cm aperture and cold, on-axis, refractive optics. BICEP2 also adopted a new detector design in which beam-defining slot antenna arrays couple to transition-edge sensor (TES) bolometers, all fabricated on a common substrate. The antenna-coupled TES detectors supported scalable fabrication and multiplexed readout that allowed BICEP2 to achieve a high detector count of 500 bolometers at 150 GHz, giving unprecedented sensitivity to B-modes at degree angular scales. After optimization of detector and readout parameters, BICEP2 achieved an instrument noise-equivalent temperature of 15.8 μK√s. The full data set reached Stokes Q and U map depths of 87.2 nK in square-degree pixels (5.'2 μK) over an effective area of 384 deg{sup 2} within a 1000 deg{sup 2} field. These are the deepest CMB polarization maps at degree angular scales to date. The power spectrum analysis presented in a companion paper has resulted in a significant detection of B-mode polarization at degree scales.

  1. Effects of feed deprivation on the AMPK signaling pathway in skeletal muscle of broiler chickens.

    PubMed

    Hu, Xiyi; Liu, Lei; Song, Zhigang; Sheikhahmadi, Ardashir; Wang, Yufeng; Buyse, Johan

    2016-01-01

    The 5'-adenosine monophosphate-activated protein kinase (AMPK) plays a key role in rapid metabolic adaptations to maintain energy homeostasis in poultry. It remains unclear if AMPK is involved in muscular energy metabolism in broiler chickens. Hence, in the present study, seven-day-old male broilers were equally divided into three groups: fed ad libitum (control); feed-deprived for 24h (S24); feed-deprived for 24h and then refed for 24h (S24R24). Compared to the control group, the plasma levels of glucose, insulin, T3 and triglycerides in the S24 group were significantly lower (P<0.05), whereas the uric acid levels were significantly higher (P<0.01). Except for glucose, refeeding for 24h reversed the fasting-induced alterations in plasma metabolite. Fasting decreased the liver kinase B1 (LKB1), AMPK alpha 2 subunit (AMPKα2), and fatty acid synthase (FAS) mRNA levels (P<0.05) in M. pectoralis major (PM). Feed deprivation did not affect the phosphorylated AKT, mammalian target of rapamycin (mTOR) and ribosomal protein S6 kinase (p70S6K) in PM (P>0.05), but upregulated carnitine palmitoyltransferase 1 (CPT1) gene expression and increased phosphorylated LKB1 (0.05muscle returned to control group levels after 24h refeeding. In M. biceps femoris (BF), the AMPKα2 and FAS mRNA levels were decreased by fasting compared to control (P<0.05), whereas CPT1 mRNA and phosphorylated LKB1 and AMPK protein levels were increased. Refeeding for 24h reversed the changes in AMPKα2 and CPT1 gene expression and phosphorylated AMPKα2 subunit. Fasting did not affect the AKT, mTOR and p70S6K in both PM and BF muscles (P>0.05). However, refeeding after 24h of fasting increased the phosphorylated mTOR level in BF muscle which was in parallel with increased plasma insulin concentration. It was likely that increased phospho-mTOR level in the BF muscle was

  2. Hamstring Fatigue and Muscle Activation Changes During Six Sets of Nordic Hamstring Exercise in Amateur Soccer Players.

    PubMed

    Marshall, Paul W M; Lovell, Ric; Knox, Michael F; Brennan, Scott L; Siegler, Jason C

    2015-11-01

    The Nordic hamstring exercise (NHE) is a bodyweight movement commonly prescribed to increase eccentric hamstring strength and reduce the incidence of strain injury in sport. This study examined hamstring fatigue and muscle activation responses throughout 6 sets of 5 repetitions of the NHE. Ten amateur-level soccer players performed a single session of 6 sets of 5 repetitions of NHE. Maximal eccentric and concentric torque output (in newton meters) was measured after every set. Hamstrings electromyograms (EMG) were measured during all maximal contractions and exercise repetitions. Hamstring maximal eccentric torque was reduced throughout the range of motion after only a single set of NHE between 7.9 and 17.1% (p ≤ 0.05), with further reductions in subsequent sets. Similarly, maximal concentric torque reductions between 7.8 and 17.2% were observed throughout the range of motion after 1 set of NHE (p ≤ 0.05). During the descent phase of the NHE repetitions, hamstring muscle activity progressively increased as the number of sets performed increased. These increases were observed in the first half of the range of motion. During the ascent phase, biceps femoris muscle activity but not medial hamstrings was reduced from the start of exercise during latter sets of repetitions. These data provide unique insight into the extent of fatigue induced from a bodyweight only exercise after a single set of 5 repetitions. Strength and conditioning coaches need to be aware of the speed and extent of fatigue induced from NHE, particularly in practical settings in which this exercise is now prescribed before sport-specific training sessions (i.e., the FIFA-11 before soccer training). PMID:25886019

  3. Dietary protein intake affects expression of genes for lipid metabolism in porcine skeletal muscle in a genotype-dependent manner.

    PubMed

    Liu, Yingying; Li, Fengna; He, Lingyun; Tan, Bie; Deng, Jinping; Kong, Xiangfeng; Li, Yinghui; Geng, Meimei; Yin, Yulong; Wu, Guoyao

    2015-04-14

    Skeletal muscle is a major site for the oxidation of fatty acids (FA) in mammals, including humans. Using a swine model, we tested the hypothesis that dietary protein intake regulates the expression of key genes for lipid metabolism in skeletal muscle. A total of ninety-six barrows (forty-eight pure-bred Bama mini-pigs (fatty genotype) and forty-eight Landrace pigs (lean genotype)) were fed from 5 weeks of age to market weight. Pigs of fatty or lean genotype were randomly assigned to one of two dietary treatments (low- or adequate-protein diet), with twenty-four individually fed pigs per treatment. Our data showed that dietary protein levels affected the expression of genes involved in the anabolism and catabolism of lipids in the longissimus dorsi and biceps femoris muscles in a genotype-dependent manner. Specifically, Bama mini-pigs had more intramuscular fat, SFA and MUFA, as well as elevated mRNA expression levels of lipogenic genes, compared with Landrace pigs. In contrast, Bama mini-pigs had lower mRNA expression levels of lipolytic genes than Landrace pigs fed an adequate-protein diet in the growing phase. These data are consistent with higher white-fat deposition in Bama mini-pigs than in Landrace pigs. In conclusion, adequate provision of dietary protein (amino acids) plays an important role in regulating the expression of key lipogenic genes, and the growth of white adipose tissue, in a genotype- and tissue-specific manner. These findings have important implications for developing novel dietary strategies in pig production.

  4. The Combined Effects of Body Weight Support and Gait Speed on Gait Related Muscle Activity: A Comparison between Walking in the Lokomat Exoskeleton and Regular Treadmill Walking

    PubMed Central

    Van Kammen, Klaske; Boonstra, Annemarijke; Reinders-Messelink, Heleen; den Otter, Rob

    2014-01-01

    Background For the development of specialized training protocols for robot assisted gait training, it is important to understand how the use of exoskeletons alters locomotor task demands, and how the nature and magnitude of these changes depend on training parameters. Therefore, the present study assessed the combined effects of gait speed and body weight support (BWS) on muscle activity, and compared these between treadmill walking and walking in the Lokomat exoskeleton. Methods Ten healthy participants walked on a treadmill and in the Lokomat, with varying levels of BWS (0% and 50% of the participants’ body weight) and gait speed (0.8, 1.8, and 2.8 km/h), while temporal step characteristics and muscle activity from Erector Spinae, Gluteus Medius, Vastus Lateralis, Biceps Femoris, Gastrocnemius Medialis, and Tibialis Anterior muscles were recorded. Results The temporal structure of the stepping pattern was altered when participants walked in the Lokomat or when BWS was provided (i.e. the relative duration of the double support phase was reduced, and the single support phase prolonged), but these differences normalized as gait speed increased. Alternations in muscle activity were characterized by complex interactions between walking conditions and training parameters: Differences between treadmill walking and walking in the exoskeleton were most prominent at low gait speeds, and speed effects were attenuated when BWS was provided. Conclusion Walking in the Lokomat exoskeleton without movement guidance alters the temporal step regulation and the neuromuscular control of walking, although the nature and magnitude of these effects depend on complex interactions with gait speed and BWS. If normative neuromuscular control of gait is targeted during training, it is recommended that very low speeds and high levels of BWS should be avoided when possible. PMID:25226302

  5. Development of estimation system of knee extension strength using image features in ultrasound images of rectus femoris

    NASA Astrophysics Data System (ADS)

    Murakami, Hiroki; Watanabe, Tsuneo; Fukuoka, Daisuke; Terabayashi, Nobuo; Hara, Takeshi; Muramatsu, Chisako; Fujita, Hiroshi

    2016-04-01

    The word "Locomotive syndrome" has been proposed to describe the state of requiring care by musculoskeletal disorders and its high-risk condition. Reduction of the knee extension strength is cited as one of the risk factors, and the accurate measurement of the strength is needed for the evaluation. The measurement of knee extension strength using a dynamometer is one of the most direct and quantitative methods. This study aims to develop a system for measuring the knee extension strength using the ultrasound images of the rectus femoris muscles obtained with non-invasive ultrasonic diagnostic equipment. First, we extract the muscle area from the ultrasound images and determine the image features, such as the thickness of the muscle. We combine these features and physical features, such as the patient's height, and build a regression model of the knee extension strength from training data. We have developed a system for estimating the knee extension strength by applying the regression model to the features obtained from test data. Using the test data of 168 cases, correlation coefficient value between the measured values and estimated values was 0.82. This result suggests that this system can estimate knee extension strength with high accuracy.

  6. Clinical anatomy and mechanical tensile properties of the rectus femoris tendon

    PubMed Central

    Zhu, Xing-Fei; Zhang, Xin-Chao

    2015-01-01

    Purpose: We aimed to provide anatomical data and mechanical tensile properties for the rectus femoris tendon to determine if it is a feasible substitute for the anterior cruciate ligament during knee joint reconstruction. Methods: The length and width of the quadriceps femoris tendon were measured from ten adult cadavers (20 knees; age =48±2 years). The anatomic features of the patellar insertion on the quadriceps femoris tendon were also documented. The rectus femoris tendon and anterior cruciate ligament were harvested from an additional five fresh specimens (10 knees; age =41±3 years). To minimize dehydration, each specimen was wrapped in saline-moistened paper towels and stored at -10°C. We imposed tensile stresses on a total of twenty samples in a sample-driven machine at 10 mm/min until the specimens failed. Results: The inserted and discrete widths of the rectus femoris tendon were 3.20±0.33 and 1.28±0.25 cm, respectively. The length of the tendon tissue was 6.96±0.80 cm and the length of mixing zone was 3.81±0.53 cm. The average thickness of the upper pole of the patella was 2.22±0.14 cm. In mechanical tensile properties, the unit modulus and unit maximum load of the rectus femoris tendon were both 63% of the anterior cruciate ligament. Conclusions: Based on its anatomical and mechanical tensile properties, the rectus femoris tendon is a feasible donor site to reconstitute the anterior cruciate ligament. PMID:26885205

  7. Proximal coracobrachialis tendon rupture, subscapularis tendon rupture, and medial dislocation of the long head of the biceps tendon in an adult after traumatic anterior shoulder dislocation

    PubMed Central

    Saltzman, Bryan M.; Harris, Joshua D.; Forsythe, Brian

    2015-01-01

    Rupture of the coracobrachialis is a rare entity, in isolation or in combination with other muscular or tendinous structures. When described, it is often a result of direct trauma to the anatomic area resulting in rupture of the muscle belly. The authors present a case of a 57-year-old female who suffered a proximal coracobrachialis tendon rupture from its origin at the coracoid process, with concomitant subscapularis tear and medial dislocation of the long head of biceps tendon after first time traumatic anterior shoulder dislocation. Two weeks after injury, magnetic resonance imaging suggested the diagnosis, which was confirmed during combined arthroscopic and open technique. Soft-tissue tenodesis of coracobrachialis to the intact short head of the biceps, tenodesis of the long head of biceps to the intertubercular groove, and double-row anatomic repair of the subscapularis were performed. The patient did well postoperatively, and ultimately at 6 months follow-up, she was without pain, and obtained 160° of active forward elevation, 45° of external rotation, internal rotation to T8, 5/5 subscapularis and biceps strength. Scoring scales had improved from the following preoperative to final follow-up: American Shoulder and Elbow Surgeons, 53.33-98.33; constant, 10-100; visual analogue scale-pain, 4-0. DASH score was 5. PMID:25937715

  8. Tomographic elastography of contracting skeletal muscles from their natural vibrations

    NASA Astrophysics Data System (ADS)

    Sabra, Karim G.; Archer, Akibi

    2009-11-01

    Conventional elastography techniques require an external mechanical or radiation excitation to measure noninvasively the viscoelastic properties of skeletal muscles and thus monitor human motor functions. We developed instead a passive elastography technique using only an array of skin-mounted accelerometers to record the low-frequency vibrations of the biceps brachii muscle naturally generated during voluntary contractions and to determine their two-dimensional directionality. Cross-correlating these recordings provided travel-times measurements of these muscle vibrations between multiple sensor pairs. Travel-time tomographic inversions yielded spatial variations of their propagation velocity during isometric elbow flexions which indicated a nonuniform longitudinal stiffening of the biceps.

  9. Signaling Pathways Related to Protein Synthesis and Amino Acid Concentration in Pig Skeletal Muscles Depend on the Dietary Protein Level, Genotype and Developmental Stages.

    PubMed

    Liu, Yingying; Li, Fengna; Kong, Xiangfeng; Tan, Bie; Li, Yinghui; Duan, Yehui; Blachier, François; Hu, Chien-An A; Yin, Yulong

    2015-01-01

    Muscle growth is regulated by the homeostatic balance of the biosynthesis and degradation of muscle proteins. To elucidate the molecular interactions among diet, pig genotype, and physiological stage, we examined the effect of dietary protein concentration, pig genotype, and physiological stages on amino acid (AA) pools, protein deposition, and related signaling pathways in different types of skeletal muscles. The study used 48 Landrace pigs and 48 pure-bred Bama mini-pigs assigned to each of 2 dietary treatments: lower/GB (Chinese conventional diet)- or higher/NRC (National Research Council)-protein diet. Diets were fed from 5 weeks of age to respective market weights of each genotype. Samples of biceps femoris muscle (BFM, type I) and longissimus dorsi muscle (LDM, type II) were collected at nursery, growing, and finishing phases according to the physiological stage of each genotype, to determine the AA concentrations, mRNA levels for growth-related genes in muscles, and protein abundances of mechanistic target of rapamycin (mTOR) signaling pathway. Our data showed that the concentrations of most AAs in LDM and BFM of pigs increased (P<0.05) gradually with increasing age. Bama mini-pigs had generally higher (P<0.05) muscle concentrations of flavor-related AA, including Met, Phe, Tyr, Pro, and Ser, compared with Landrace pigs. The mRNA levels for myogenic determining factor, myogenin, myocyte-specific enhancer binding factor 2 A, and myostatin of Bama mini-pigs were higher (P<0.05) than those of Landrace pigs, while total and phosphorylated protein levels for protein kinase B, mTOR, and p70 ribosomal protein S6 kinases (p70S6K), and ratios of p-mTOR/mTOR, p-AKT/AKT, and p-p70S6K/p70S6K were lower (P<0.05). There was a significant pig genotype-dependent effect of dietary protein on the levels for mTOR and p70S6K. When compared with the higher protein-NRC diet, the lower protein-GB diet increased (P<0.05) the levels for mTOR and p70S6K in Bama mini-pigs, but

  10. The Gluteus Medius Vs. Thigh Muscles Strength Ratio and Their Relation to Electromyography Amplitude During a Farmer’s Walk Exercise

    PubMed Central

    Stastny, Petr; Lehnert, Michal; Zaatar, Amr; Svoboda, Zdenek; Xaverova, Zuzana; Pietraszewski, Przemysław

    2015-01-01

    The strength ratio between hamstrings and quadriceps (H/Q) is associated with knee injuries as well as hip abductor muscle (HAB) weakness. Sixteen resistance trained men (age, 32.5 ± 4.2 years) performed 5 s maximal isometric contractions at 75° of knee flexion/extension and 15° of hip abduction on a dynamometer. After this isometric test they performed a Farmer’s walk exercise to find out if the muscle strength ratio predicted the electromyography amplitude expressed as a percentage of maximum voluntary isometric contraction (%MVIC). The carried load represented a moderate intensity of 75% of the exercise six repetitions maximum (6RM). Electromyography data from the vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF) and gluteus medius (Gmed) on each leg were collected during the procedure. The groups selected were participants with H/Q ≥ 0.5, HQ < 0.5, HAB/H ≥ 1, HAB/H < 1, HAB/Q ≥ 0.5 and HAB/Q < 0.5. One way ANOVA showed that Gmed activity was significantly greater in the group with HAB/H < 1 (42 ± 14 %MVIC) as compared to HAB/H ≥ 1 (26 ± 10 %MVIC) and HAB/Q < 0.5 (47 ± 19 %MVIC) compared to HAB/Q ≥ 0.5 (26 ± 12 %MVIC). The individuals with HAB/H < 1 were found to have greater activation of their Gmed during the Farmer’s walk exercise. Individuals with HAB/Q < 0.5 had greater activation of the Gmed. Gmed strength ratios predict the muscle involvement when a moderate amount of the external load is used. The Farmer’s walk is recommended as an exercise which can strengthen the gluteus medius, especially for individuals with a HAB/H ratio < 1 and HAB/Q < 0.5. PMID:25964819

  11. Effects of implanting ram and wether lambs with zeranol at birth and weaning on palatability and muscle collagen characteristics.

    PubMed

    Nold, R A; Unruh, J A; Hunt, M C; Spaeth, C W

    1992-09-01

    Thirty-five zeranol-implanted (I) and nonimplanted (NI) ram and wether lambs representing four treatments (implanted rams [IR], nonimplanted rams [NIR], implanted wethers [IW], and nonimplanted wethers [NIW]) were evaluated for meat palatability and muscle collagen characteristics. Rib (longissimus muscle, LM) chops from I lambs were juicier (P less than .05) than rib chops from NI lambs. Chops from IR lambs had more (P less than .05) detectable connective tissue and lower myofibrillar and overall tenderness scores than chops from NIR, IW, or NIW lambs. Warner-Bratzler shear (WBS) values tended to be higher (P = .06) for LM chops from rams than for those from wethers, but WBS values for Biceps femoris (BF) chops were similar (P greater than .05) for rams and wethers. Implanting did not affect (P greater than .05) WBS values. Rams had more (P less than .05) LM heat-labile (soluble, SC), nonheat-labile (insoluble, IC), and total collagen (TC) and a higher (P less than .05) percentage of SC (SC/TC) than did wethers. Soluble collagen, TC, and percentage of SC for the BF were higher (P less than .05) and IC tended (P = .09) to be higher in chops from rams than in those from wethers. Implanting did not affect (P greater than .05) collagen amount or solubility. Serum nonprotein hydroxyproline (NPHP) was higher (P less than .05) in rams than in wethers throughout the feeding period and tended (P = .05) to be higher at slaughter. Implanting did not affect (P greater than .05) serum NPHP.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. The functional effect of a distal rectus femoris tenotomy in adults with cerebral palsy.

    PubMed

    Drefus, Lisa C; Buckland, Melanie A; Backus, Sherry I; Root, Leon

    2014-01-01

    The purpose of this study was to determine the effect of a distal rectus femoris tenotomy on function and gait in adults with cerebral palsy who had diminished knee flexion during swing. A stiff knee gait pattern is commonly seen in individuals with cerebral palsy and frequently leads to tripping and falling. Five subjects, 25-51 years, (34.6±10.3 years) participated in the study; each individual had the surgery after the age of 18. Four of the five subjects underwent bilateral distal rectus femoris tenotomies for a total of nine limbs being studied. Four of the five subjects had a single procedure of a distal rectus femoris tenotomy and one subject also had bilateral adductor tenotomies. All individuals underwent a pre-operative and post-operative, (3.28±1.6 years) three-dimensional gait analysis. Pre-operative gait revealed diminished peak knee flexion and out of phase rectus femoris activity with a quiet vastus lateralis during swing in all subjects. Significant findings after a distal rectus femoris tenotomy included: improved peak swing knee flexion, improved peak stance hip extension, and increased total knee excursion without loss in knee extension strength. During swing, knee flexion angle improved on average 11° which correlated with subjective report of less shoe wear, tripping, and falling due to improved clearance. In conclusion, a distal rectus femoris tenotomy should be considered a surgical option for adults with cerebral palsy and a stiff knee gait pattern to improve mobility, function, and quality of life. PMID:24742707

  13. The functional effect of a distal rectus femoris tenotomy in adults with cerebral palsy.

    PubMed

    Drefus, Lisa C; Buckland, Melanie A; Backus, Sherry I; Root, Leon

    2014-01-01

    The purpose of this study was to determine the effect of a distal rectus femoris tenotomy on function and gait in adults with cerebral palsy who had diminished knee flexion during swing. A stiff knee gait pattern is commonly seen in individuals with cerebral palsy and frequently leads to tripping and falling. Five subjects, 25-51 years, (34.6±10.3 years) participated in the study; each individual had the surgery after the age of 18. Four of the five subjects underwent bilateral distal rectus femoris tenotomies for a total of nine limbs being studied. Four of the five subjects had a single procedure of a distal rectus femoris tenotomy and one subject also had bilateral adductor tenotomies. All individuals underwent a pre-operative and post-operative, (3.28±1.6 years) three-dimensional gait analysis. Pre-operative gait revealed diminished peak knee flexion and out of phase rectus femoris activity with a quiet vastus lateralis during swing in all subjects. Significant findings after a distal rectus femoris tenotomy included: improved peak swing knee flexion, improved peak stance hip extension, and increased total knee excursion without loss in knee extension strength. During swing, knee flexion angle improved on average 11° which correlated with subjective report of less shoe wear, tripping, and falling due to improved clearance. In conclusion, a distal rectus femoris tenotomy should be considered a surgical option for adults with cerebral palsy and a stiff knee gait pattern to improve mobility, function, and quality of life.

  14. On the effect of thermal agents in the response of the brachial biceps at different contraction levels.

    PubMed

    Garcia, Larissa Martins; Soares, Alcimar Barbosa; Simieli, Camila; Boratino, Alessandra Vairo Peres; Guirro, Rinaldo Roberto de Jesus

    2014-12-01

    The objective of this study was to assess electromyographic features of the brachial biceps muscle after the application of cryotherapy and short-wave diathermy. Sixty healthy volunteers participated in the study and were equally divided into three groups: cryotherapy - application of ice packs for 30 min; short-wave diathermy for 20 min; and control. The thermal agents were applied to the anterior and posterior regions of the non-dominant arm. The electromyographic (EMG) signal from the brachial biceps was recorded before and after the application of thermal agents during flexion of the elbow joint at 25%, 50%, 75% of a maximum voluntary isometric contraction defined at least two days before the actual experiments (MVICbl). The volunteers also were asked to execute a free MVIC before and after the application of the thermal agents (MVIC free). A linear regression model with mixed effects (random and fixed) was used. Intra-group analysis showed a reduction in root mean square (RMS) at MVIC free, with no change in the median frequency of the EMG signal at any contraction level for the short-wave diathermy group. An increase on RMS values and a decrease on median frequencies were found after the application of cryotherapy for all contraction levels. The results imply that cryotherapy plays an important role on changing neuromuscular responses at various levels of muscle contraction. Therapists should be aware of that and carefully consider its use prior to activities in which neuromuscular precision is required. PMID:25148950

  15. Effect of high-load and high-volume resistance exercise on the tensiomyographic twitch response of biceps brachii.

    PubMed

    García-Manso, Juan Manuel; Rodríguez-Matoso, Darío; Sarmiento, Samuel; de Saa, Yves; Vaamonde, Diana; Rodríguez-Ruiz, David; Da Silva-Grigoletto, Marzo Edir

    2012-08-01

    The purpose of the present study was to assess the ability of TMG in detecting mechanical fatigue induced by two different resistance exercises on biceps brachii: high-volume (HV), and high-load (HL). Sixteen healthy subjects (age 25.1±2.6years; body mass 79.9±8.9kg; height 179±7.4cm) performed arm-curl in two different protocols (HV: 8×15×10kg, HL: 5×3×30kg). Tensiomyography was used to assess muscle response to both exercise protocols. The contractile capacity of biceps brachii significantly varied by means of the effects of potentiation and fatigue mechanisms that take place at different exercise phases. The most significant changes correspond to values of maximum radial displacement of muscle belly (D(m)), sustained contraction time (T(s)), relaxation time (T(r)), and contraction velocity (V(c)). The behavior of these parameters is, in general, similar in both exercise protocols, but they show subtle differences among them. During the first set, in both protocols, values for V(c) increase, along with a decrease in T(r), T(s), and D(m) values. Fatigue onset was evident from changes in such parameters, with HL being the first in showing these mechanisms. Tensiomyography has been shown to be highly sensitive in detecting fatigue-induced changes.

  16. Evidence for bouncing evolution before inflation after BICEP2.

    PubMed

    Xia, Jun-Qing; Cai, Yi-Fu; Li, Hong; Zhang, Xinmin

    2014-06-27

    The BICEP2 Collaboration reports a detection of primordial cosmic microwave background (CMB) B mode with a tensor-to-scalar ratio r = 0.20(-0.05)(+0.07) (68% C.L.). However, this result disagrees with the recent Planck limit r < 0.11 (95% C.L.) on constraining inflation models. In this Letter we consider an inflationary cosmology with a preceding nonsingular bounce, which gives rise to observable signatures on primordial perturbations. One interesting phenomenon is that both the primordial scalar and tensor modes can have a step feature on their power spectra, which nicely cancels the tensor excess power on the CMB temperature power spectrum. By performing a global analysis, we obtain the 68% C.L. constraints on the parameters of the model from the Planck+WP and BICEP2 data together: the jump scale log(10)(k(B)/Mpc(-1)) = -2.4 ± 0.2 and the spectrum amplitude ratio of bounce to inflation r(B) ≡ P(m)/A(s) = 0.71 ± 0.09. Our result reveals that the bounce inflation scenario can simultaneously explain the Planck and BICEP2 observations better than the standard cold dark matter model with a cosmological constant, and can be verified by future CMB polarization measurements.

  17. Inflation after false vacuum decay: new evidence from BICEP2

    SciTech Connect

    Bousso, Raphael; Harlow, Daniel; Senatore, Leonardo E-mail: dharlow@princeton.edu

    2014-12-01

    Last year we argued that if slow-roll inflation followed the decay of a false vacuum in a large landscape, the steepening of the scalar potential between the inflationary plateau and the barrier generically leads to a potentially observable suppression of the scalar power spectrum at large distances. Here we revisit this analysis in light of the recent BICEP2 results. Assuming that both the BICEP2 B-mode signal and the Planck analysis of temperature fluctuations hold up, we find that the data now discriminate more sharply between our scenario and ΛCDM. Nonzero tensor modes exclude standard ΛCDM with notable but not yet conclusive confidence: at ∼3.8σ if r = 0.2, or at ∼ 3.5σ if r = 0.15. Of the two steepening models of our previous work, one is now ruled out by existing bounds on spatial curvature. The other entirely reconciles the tension between BICEP2 and Planck. Upcoming EE polarization measurements have the potential to rule out unmodified ΛCDM decisively. Next generation Large Scale Structure surveys can further increase the significance. More precise measurements of BB at low ℓ will help distinguish our scenario from other explanations. If steepening is confirmed, the prospects for detecting open curvature increase but need not be large.

  18. Age independent and position-dependent alterations in motor unit activity of the biceps brachii.

    PubMed

    Harwood, B; Edwards, D L; Jakobi, J M

    2010-09-01

    In the biceps brachii, age-related differences in synaptic excitability and muscle architecture may affect motor unit (MU) activity differently depending on the position of the forearm. It was hypothesised that as a result of these age-related differences, greater changes in MU activity would accompany a change in forearm position in old when compared with young men. Six young (22 +/- 3 years) and six old (84 +/- 3 years) men maintained isometric elbow flexion at 10% of maximal voluntary contraction (MVC) during changes in forearm position. Forty-nine MUs in the short (SBB) and long (LBB) heads of the biceps brachii were followed. Motor unit recruitment and de-recruitment thresholds, motor unit discharge rates (MUDRs), and MU discharge variability were measured. Although an age-related decrease in MU recruitment thresholds, and increase in MU discharge variability was evident, changes in forearm position influenced MUDRs similarly in young and old men (P = 0.27). Motor unit recruitment thresholds of the SBB were highest in the pronated position (8.2 +/- 2.9 %MVC), whereas in the LBB they were highest in the supinated position (8.6 +/- 2.0 %MVC). Motor unit discharge rates of the LBB did not change with forearm position. In the SBB, MUDRs were highest when the forearm was supinated, and also greater when compared with the LBB in this position. No position-dependent changes were observed for MU discharge variability in the LBB, but the SBB exhibited greatest MU discharge variability in the pronated position. The results suggest that MU activity is modulated following a change in forearm position, but the response is similar in young and old adults.

  19. Differential Changes with Age in Multiscale Entropy of Electromyography Signals from Leg Muscles during Treadmill Walking

    PubMed Central

    Kang, Hyun Gu; Dingwell, Jonathan B.

    2016-01-01

    Age-related gait changes may be due to the loss of complexity in the neuromuscular system. This theory is disputed due to inconsistent results from single-scale analyses. Also, behavioral adaptations may confound these changes. We examined whether EMG dynamics during gait is less complex in older adults over a range of timescales using the multiscale entropy method, and whether slower walking attenuates this effect. Surface EMG was measured from the left vastus lateralis (VL), biceps femoris (BF), gastrocnemius (GA), and tibialis anterior (TA) in 17 young and 18 older adults as they walked on a treadmill for 5 minutes at 0.8x-1.2x of preferred speed. Sample entropy (SE) and the complexity index (CI) of the EMG signals were calculated after successive coarse-graining to extract dynamics at timescales of 27 to 270 Hz, with m = 2 and r = 0.15 SD. SE and CI were lower across the timescales in older adults in VL and BF, but higher in GA (all p<0.001); these results held for VL and GA even after accounting for longer EMG burst durations in older adults. CI was higher during slower walking speed in VL and BF (p<0.001). Results were mostly similar for m = 3 and r = 0.01–0.35. Smaller r was more sensitive to age-related differences. The decrease in complexity with aging in the timescales studied was limited to proximal muscles, particularly VL. The increase in GA may be driven by other factors. Walking slower may reflect a behavioral adaptation that allows the nervous system to function with greater complexity. PMID:27570974

  20. Toxic heavy metals in the muscle of roe deer (Capreolus capreolus)--food toxicological significance.

    PubMed

    Lehel, József; Laczay, Péter; Gyurcsó, Adrienn; Jánoska, Ferenc; Majoros, Szilvia; Lányi, Katalin; Marosán, Miklós

    2016-03-01

    The study was performed on 20 (10 males, 10 females) roe deer (Capreolus capreolus) to investigate the concentration of cadmium, lead, mercury, and arsenic in the muscle tissue. They reside in forest and meadow, about 50 km distance from industrial activities and traffic. Samples were taken from the musculus biceps femoris of each deer without external contamination after shooting during the regular hunting season on a hunting area close to Eger in Hungary. The determination of heavy metal contents was carried out by inductively coupled plasma optical emission spectrometry (ICP-OES). The statistical analysis was performed by statistical package for the social sciences (SPSS) version 11.0. The measured residue concentration of cadmium was below the limit of detection in the roe deer meat indicating no health risk for the consumers. The average lead concentration (0.48 ± 0.21 mg/kg wet weight) exceeded the regulated maximum limit, but its calculated weekly intake was below the provisional tolerable weekly intake (PTWI). The residue level of mercury is not regulated and the average mercury content of roe deer meat (0.87 ± 0.40 mg/kg wet weight) was about half of PTWI, but the consumption of meat with the highest detected concentrations results in higher PTWI than recommended. The measured concentration of arsenic (0.27 ± 0.20 mg/kg wet weight) in the roe deer meat may not pose any health risk for the human consumers according to the PTWI set by the World Health Organization.

  1. Differential Changes with Age in Multiscale Entropy of Electromyography Signals from Leg Muscles during Treadmill Walking.

    PubMed

    Kang, Hyun Gu; Dingwell, Jonathan B

    2016-01-01

    Age-related gait changes may be due to the loss of complexity in the neuromuscular system. This theory is disputed due to inconsistent results from single-scale analyses. Also, behavioral adaptations may confound these changes. We examined whether EMG dynamics during gait is less complex in older adults over a range of timescales using the multiscale entropy method, and whether slower walking attenuates this effect. Surface EMG was measured from the left vastus lateralis (VL), biceps femoris (BF), gastrocnemius (GA), and tibialis anterior (TA) in 17 young and 18 older adults as they walked on a treadmill for 5 minutes at 0.8x-1.2x of preferred speed. Sample entropy (SE) and the complexity index (CI) of the EMG signals were calculated after successive coarse-graining to extract dynamics at timescales of 27 to 270 Hz, with m = 2 and r = 0.15 SD. SE and CI were lower across the timescales in older adults in VL and BF, but higher in GA (all p<0.001); these results held for VL and GA even after accounting for longer EMG burst durations in older adults. CI was higher during slower walking speed in VL and BF (p<0.001). Results were mostly similar for m = 3 and r = 0.01-0.35. Smaller r was more sensitive to age-related differences. The decrease in complexity with aging in the timescales studied was limited to proximal muscles, particularly VL. The increase in GA may be driven by other factors. Walking slower may reflect a behavioral adaptation that allows the nervous system to function with greater complexity. PMID:27570974

  2. A Predictive Mathematical Model of Muscle Forces for Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Lee, Samuel C. K.; Ding, Jun; Prosser, Laura A.; Wexler, Anthony S.; Binder-Macleod, Stuart A.

    2009-01-01

    Aim: The purpose of this study was to determine if our previously developed muscle model could be used to predict forces of the quadriceps femoris and triceps surae muscles of children with spastic diplegic cerebral palsy (CP). Method: Twenty-two children with CP (12 males, 10 females; mean age 10y, SD 2y, range 7-13y; Gross Motor Function…

  3. BICEP2/SPUD: Searching for Inflation with Degree Scale Polarimetry from the South Pole

    NASA Technical Reports Server (NTRS)

    Nguyen, Hien Trong; Kovac, John; Adec, Peter; Aikin, Randol; Benton, Steve; Bock, Jamie; Brevik, Justus; Carlstrom, John; Dowell, Darren; Duband, Lionel; Golwala, Sunil; Halpern, Mark; Hasselfield, Matthew; Irwin, Kent; Jones, William; Kaufman, Jonathan; Keating, Brian; Kuo, Chao-Lin; Lange, Andrew; Matsumura, Tomotake; Netterfield, Barth; Pryke, Clem; Ruhl, John; Sheehy, Chris; Sudiwala, Rashmi

    2008-01-01

    BICEP2/SPUD is the new powerful upgrade of the existing BICEP1 experiment, a bolometric receiver to study the polarization of the cosmic microwave background radiation, which has been in operation at the South Pole since January 2006. BICEP2 will provide an improvement up to 10 times mapping speed at 150 GHz compared to BICEP1, using the same BICEP telescope mount. SPUD, a series of compact, mechanically-cooled receivers deployed on the DASI mount at the Pole, will provide similar mapping speed in to BICEP2 in three bands, 100, 150, and 220 GHz. The new system will use large TES focal plane arrays to provide unprecedented sensitivity and excellent control of foreground contamination.

  4. Creatine Loading, Resistance Exercise Performance, and Muscle Mechanics.

    ERIC Educational Resources Information Center

    Stevenson, Scott W.; Dudley, Gary A.

    2001-01-01

    Examined whether creatine (CR) monohydrate loading would alter resistance exercise performance, isometric strength, or in vivo contractile properties of the quadriceps femoris muscle compared with placebo loading in resistance-trained athletes. Overall, CR loading did not provide an ergogenic benefit for the unilateral dynamic knee extension…

  5. Operator performance and localized muscle fatigue in a simulated space vehicle control task

    NASA Technical Reports Server (NTRS)

    Lewis, J. L., Jr.

    1979-01-01

    Fourier transforms in a special purpose computer were utilized to obtain power spectral density functions from electromyograms of the biceps brachii, triceps brachii, brachioradialis, flexor carpi ulnaris, brachialis, and pronator teres in eight subjects performing isometric tracking tasks in two directions utilizing a prototype spacecraft rotational hand controller. Analysis of these spectra in general purpose computers aided in defining muscles involved in performing the task, and yielded a derived measure potentially useful in predicting task termination. The triceps was the only muscle to show significant differences in all possible tests for simple effects in both tasks and, overall, was the most consistently involved of the six muscles. The total power monitored for triceps, biceps, and brachialis dropped to minimal levels across all subjects earlier than for other muscles. However, smaller variances existed for the biceps, brachioradialis, brachialis, and flexor carpi ulnaris muscles and could provide longer predictive times due to smaller standard deviations for a greater population range.

  6. Structural changes in arm muscles after microgravity.

    PubMed

    Mayet-Sornay, M H; Hoppeler, H; Shenkman, B S; Desplanches, D

    2000-01-01

    Disuse muscle atrophy is a well-known consequence of spaceflight. However, most of the available muscle data concern lower limb muscles of rats and primates exposed to microgravity aboard Russian Cosmos biosatellites and American Space Shuttles. The purpose of our study was, therefore, to provide information concerning the effects of a 14-day spaceflight on two upper limb muscles of rhesus monkeys (Macaca mulatta). Our objective was to compare structural adaptations after 14 days of microgravity in a slow-twitch extensor muscle, i.e., the triceps, with a fast-twitch flexor muscle, i.e., the biceps. We hypothesize that muscle responses will be muscle specific, i.e., slow will differ from fast muscles, flexors will differ from extensors, and arms will differ from legs.

  7. Motor unit activity in biceps brachii of left-handed humans during sustained contractions with two load types.

    PubMed

    Gould, Jeffrey R; Cleland, Brice T; Mani, Diba; Amiridis, Ioannis G; Enoka, Roger M

    2016-09-01

    The purpose of the study was to compare the discharge characteristics of single motor units during sustained isometric contractions that required either force or position control in left-handed individuals. The target force for the two sustained contractions (24.9 ± 10.5% maximal force) was identical for each biceps brachii motor unit (n = 32) and set at 4.7 ± 2.0% of maximal voluntary contraction (MVC) force above its recruitment threshold (range: 0.5-41.2% MVC force). The contractions were not sustained to task failure, but the duration (range: 60-330 s) was identical for each motor unit and the decline in MVC force immediately after the sustained contractions was similar for the two tasks (force: 11.1% ± 13.7%; position: 11.6% ± 9.9%). Despite a greater increase in the rating of perceived exertion during the position task (task × time interaction, P < 0.006), the amplitude of the surface-recorded electromyogram for the agonist and antagonist muscles increased similarly during the two tasks. Nonetheless, mean discharge rate of the biceps brachii motor units declined more during the position task (task × time interaction, P < 0.01) and the variability in discharge times (coefficient of variation for interspike interval) increased only during the position task (task × time interaction, P < 0.008). When combined with the results of an identical study on right-handers (Mottram CJ, Jakobi JM, Semmler JG, Enoka RM. J Neurophysiol 93: 1381-1392, 2005), the findings indicate that handedness does not influence the adjustments in biceps brachii motor unit activity during sustained submaximal contractions requiring either force or position control.

  8. The response of various muscle types to a restriction -re-alimentation feeding strategy in growing pigs.

    PubMed

    Lebret, B; Heyer, A; Gondret, F; Louveau, I

    2007-07-01

    Muscle lipid concentration is known to influence pork eating quality. This study aimed at evaluating the effect of a restriction-re-alimentation feeding strategy on intramuscular fat deposition in pigs. A total of 70 Duroc × (Large White × Landrace) pigs (castrated males and females) were used. Ten pigs were first slaughtered at 30 kg live weight (LW) to determine initial body and muscle composition. From 30 to 80 kg LW (growing period), pigs were either fed ad libitum (AL) or restricted to 70% of the ad libitum intake of AL pigs (RA). From 80 to 110 kg LW (finishing period), both AL and RA pigs were fed ad libitum. In each group, pigs were slaughtered at 80 kg (n = 10) and at 110 kg (n = 20) LW. During the growing period, the growth rate of RA pigs was reduced by 30% (P < 0.001) compared with AL pigs. During the finishing period, RA pigs had a 7% (P = 0.09) higher growth rate than AL pigs due to compensatory feed intake (+14%). Plasma insulin-like growth factor-1 concentration was lower in RA pigs at 80 kg LW, but markedly increased after re-alimentation up to the level observed in AL pigs (P < 0.001). At 80 kg, the leaner carcasses of RA pigs resulted from a more pronounced reduction in fat than in lean tissue deposition rates. Re-alimentation of RA pigs increased fat tissue deposition (+160% for females, P < 0.01) but not lean deposition in the carcass, leading to limited differences in carcass composition between RA and AL pigs at 110 kg LW. Regarding tissue deposition rates, the response to feeding strategy differs between muscles. In the m. biceps femoris (BF), restriction affected lipid (-50%, P < 0.001) and protein (-25%, P < 0.001) deposition, whereas re-alimentation increased lipid (+62%, P < 0.05) but not protein deposition rates. At market weight, the extent of the difference in BF lipid concentration between RA and AL pigs was strongly reduced, but still significant. By contrast, in the m. longissimus, restriction decreased protein but not lipid

  9. Acute changes in muscle activation and leg extension performance after different running exercises in elite long distance runners.

    PubMed

    Vuorimaa, Timo; Virlander, Rami; Kurkilahti, Pasi; Vasankari, Tommi; Häkkinen, Keijo

    2006-02-01

    This study investigated acute changes in muscle activation and muscular power performance after three different running exercises in elite long-distance runners. Twenty-two nationally and internationally ranked long-distance runners performed first an incremental treadmill running test until exhaustion (MR) and then 40 min continuous (TR) and intermittent (2 min run/2 min rest) (IR) running exercises at an intensity of 80 and 100% of the velocity associated with VO(2max), respectively. Muscle activation and muscular power performance tests (counter-movement jumps, CMJ, and a set of ten maximal half squats from the static starting position with an extra load of 35% of the subjects, one repetition maximum) were performed before and immediately after the runs. The average mechanical power (P) of the half squats was calculated and the root mean square electromyogram (EMGrms) from the vastus lateralis, vastus medialis, gastrocnemius and biceps femoris muscles was recorded simultaneously during the half squat performances. The results showed an acute exercise-induced increase in P (ANOVA time effect, P = 0.000) together with a reduction in EMGrms of the knee extensor muscles (ANOVA time effect, P = 0.000). However, mechanical P expressed as a relative change within the set decreased after MR. In TR the improvement in P correlated positively with the maximal running performance of the runners (P < 0.05), while in IR it correlated negatively (P < 0.05). Jumping performance was significantly enhanced after each run (P < 0.001, for all) and the improvement correlated negatively with the maximal sprinting speed and maximal jumping height of the runners (P < 0.01, for all). It is concluded that in elite long distance runners an intensive prolonged running exercise reduces the surface EMG of the knee extensor muscles, and may lead to a different coordination strategy in leg extension exercises performed into the vertical direction. After continuous type of running the power

  10. Nonsingular bouncing cosmologies in light of BICEP2

    SciTech Connect

    Cai, Yi-Fu; Quintin, Jerome; Saridakis, Emmanuel N.; Wilson-Ewing, Edward E-mail: jquintin@physics.mcgill.ca E-mail: wilson-ewing@phys.lsu.edu

    2014-07-01

    We confront various nonsingular bouncing cosmologies with the recently released BICEP2 data and investigate the observational constraints on their parameter space. In particular, within the context of the effective field approach, we analyze the constraints on the matter bounce curvaton scenario with a light scalar field, and the new matter bounce cosmology model in which the universe successively experiences a period of matter contraction and an ekpyrotic phase. Additionally, we consider three nonsingular bouncing cosmologies obtained in the framework of modified gravity theories, namely the Hořava-Lifshitz bounce model, the f(T) bounce model, and loop quantum cosmology.

  11. Influence of hip external rotation on hip adductor and rectus femoris myoelectric activity during a dynamic parallel squat.

    PubMed

    Pereira, Glauber Ribeiro; Leporace, Gustavo; Chagas, Daniel das Virgens; Furtado, Luis F L; Praxedes, Jomilto; Batista, Luiz A

    2010-10-01

    This study sought to compare the myoelectric activity of the hip adductors (HAs) and rectus femoris (RF) when the hip was in a neutral position or externally rotated by 30° or 50° (H0, H30, and H50, respectively) during a parallel squat. Ten healthy subjects performed 10 repetitions of squats in each of the 3 hip positions and the myoelectric activities of the HAs and RF were recorded. The signal was then divided into categories representing concentric (C) and eccentric (E) contractions in the following ranges of motion: 0-30° (C1 and E1), 30-60° (C2 and E2), and 60-90° (C3 and E3) of knee flexion. From those signals, an root mean square (RMS) value for each range of motion in each hip position was obtained. All values were normalized to those obtained during maximum voluntary isometric contraction. We found that HAs showed a significant increase in myoelectric activity during C3 and E3 in the H30 and H50 positions, as compared with H0. Meanwhile, RF activity did not significantly differ between hip positions. Both muscles showed higher activation during 60-90° (C3 and E3) of knee flexion, as compared with 0-30° (C1 and E1) and 30-60° (C2 and E2). The results suggest that if the aim is to increase HA activity despite the low percentage of muscle activation, squats should be performed with 30° of external rotation and at least 90° of knee flexion. PMID:20651607

  12. Tendinopathy of the long head of the biceps tendon: histopathologic analysis of the extra-articular biceps tendon and tenosynovium

    PubMed Central

    Streit, Jonathan J; Shishani, Yousef; Rodgers, Mark; Gobezie, Reuben

    2015-01-01

    Background Bicipital tendinitis is a common cause of anterior shoulder pain, but there is no evidence that acute inflammation of the extra-articular long head of the biceps (LHB) tendon is the root cause of this condition. We evaluated the histologic findings of the extra-articular portion of the LHB tendon and synovial sheath in order to compare those findings to known histologic changes seen in other tendinopathies. Methods Twenty-six consecutive patients (mean age 45.4±13.7 years) underwent an open subpectoral biceps tenodesis for anterior shoulder pain localized to the bicipital groove. Excised tendons were sent for histologic analysis. Specimens were graded using a semiquantitative scoring system to evaluate tenocyte morphology, the presence of ground substance, collagen bundle characteristics, and vascular changes. Results Chronic inflammation was noted in only two of 26 specimens, and no specimen demonstrated acute inflammation. Tenocyte enlargement and proliferation, characterized by increased roundness and size of the cell and nucleus with proteoglycan matrix expansion and myxoid degenerative changes, was found in all 26 specimens. Abundant ground substance, collagen bundle changes, and increased vascularization were visualized in all samples. Conclusion Anterior shoulder pain attributed to the biceps tendon does not appear to be due to an inflammatory process in most cases. The histologic findings of the extra-articular portion of the LHB tendon and synovial sheath are similar to the pathologic findings in de Quervain tenosynovitis at the wrist, and may be due to a chronic degenerative process similar to this and other tendinopathies of the body. PMID:25792859

  13. Reliability of manual versus automated techniques for assessing passive stiffness of the posterior muscles of the hip and thigh.

    PubMed

    Palmer, Ty B; Jenkins, Nathaniel D M; Cramer, Joel T

    2013-01-01

    The purpose of this study was to compare the reliability of passive stiffness, passive torque, range of motion (ROM), and electromyography (EMG) of the biceps femoris during passive thigh flexion motions intended to assess the ROM of the posterior muscles of the hip and thigh during manual versus automated assessment techniques. Eleven healthy men (mean ± s age = 22 ± 4 years; mass = 85 ± 12 kg; and height = 178 ± 4 cm) and nine healthy women (age = 19 ± 1 years; mass = 66 ± 15 kg; and height = 164 ± 5 cm) completed four randomly ordered passive straight-legged ROM assessments. Two ROM assessments were performed using a manual technique, which consisted of the primary investigator applying slow passive resistance against a load cell attached to the heel while the foot was moved toward the head. Two automated ROM assessments were also performed using a Biodex System 3 isokinetic dynamometer programmed in passive mode to move the foot toward the head at 0.087 rad · s(-1). The intraclass correlation coefficients (ICCs) for passive stiffness measured with the manual technique ranged from 0.81-0.86, while for the automated technique they were 0.72-0.92. Standard error of measurement (SEM) values for passive stiffness expressed as a percentage of the mean ranged from 15.5-21.7% for the manual and 17.8-23.7% for the automated technique. Both techniques (manual and automated) were comparably reliable across the three trials, which suggested that the manual technique could be applied outside the laboratory.

  14. Partial rupture of the quadriceps muscle in a child

    PubMed Central

    2010-01-01

    Background The quadriceps femoris muscle ruptures usually occur in the middle-aged population. We present a 4-year-old patient with partial rupture of the quadriceps femoris muscle. To our knowledge, this is the youngest patient reported with a quadriceps femoris muscle rupture. Case Presentation A 4-year-old girl admitted to our clinic with left knee pain and limitation in knee movements. Her father reported that she felt pain while jumping on sofa. There was no direct trauma to thigh or knee. We located a palpable soft tissue swelling at distal anterolateral side of thigh. The history revealed that 10 days ago the patient was treated for upper tract respiratory infection with intramuscular Clindamycin for 7 days. When we consulted the patient with her previous doctor and nurse, we learnt that multiple daily injections might be injected to same side of left thigh. MRI showed a partial tear of vastus lateralis muscle matching with the injection sites. The patient treated with long leg half-casting for three weeks. Clinical examination and knee flexion had good results with conservative treatment. Conclusions Multiple intramuscular injections may contribute to damage muscles and make prone to tears with muscle contractions. Doctors and nurses must be cautious to inject from different parts of both thighs. PMID:20849662

  15. Firing rate analysis using decompostion-enhanced spike triggered averaging in the quadriceps femoris.

    PubMed

    Conwit, R A; Tracy, B; Cowl, A; McHugh, M; Stashuk, D; Brown, W F; Metter, E J

    1998-10-01

    Electromyographic signals detected from the quadriceps femoris during various constant force contractions were decomposed to identify individual motor unit discharges and mean firing rates (FRs). Subject and group mean FRs were calculated for each force level. Mean FR values and FR variability increased with force. Individual, subject, and group mean FRs showed slight increases until 30% of maximum voluntary contraction and larger increases thereafter. Findings are discussed in relation to motor unit recruitment, frequency modulation, and fatigue. PMID:9736067

  16. Interaction of Gender and Body Composition on Rectus Femoris Morphology as Measured With Musculoskeletal Ultrasound Imaging

    PubMed Central

    Martinez, Corina; Davis, Ashley; Myers, Heather; Butler, Robert J.

    2014-01-01

    Background: Quadriceps function is an important measure in patients recovering postoperatively. Traditionally, strength measures that require high levels of resistance are contraindicated during the early postoperative phase. Thus it may be helpful to evaluate the utilization of other tools, such as ultrasound imaging, that allow for assessment during a position of low resistance. Hypothesis: The rectus femoris cross-sectional area (CSA) is affected by sex and body composition in healthy subjects. Study Design: Cross-sectional study. Level of Evidence: Level 4. Methods: Thirty-two healthy subjects (16 women, 16 men), selected from a previously larger study, were chosen for analysis. All subjects underwent a maximal volitional isometric contraction protocol from 0° to 90° of knee motion controlled by an isokinetic dynamometer. In the contracted and resting positions, the rectus femoris CSA was measured at each angle using ultrasound imaging. The contractile index (contracted − resting CSA) was calculated at each position. Subjects were separated into 1 of 4 groups based on sex and fat percentage (low or high). These data were analyzed using mixed-factor analysis of variance (group × angle) for each variable, with a critical α level of 0.05. Results: A significant interaction was noted for the CSA of the rectus femoris at rest (P < 0.03) and during contraction (P < 0.02). For both variables, all groups performed similarly, with the exception of women with high body fat percentage. No statistically significant interaction existed for the contractile index; however, a main effect for angle (P < 0.01) was observed. Conclusion: Rectus femoris CSA appears to depend on sex as well as the body composition of individuals. Clinical Relevance: Traditional subjective assessment measures of quadriceps strength and function have low reliability and functional validity. With the improved feasibility of ultrasound imaging in the clinical setting, quadriceps size may be more

  17. Peak muscle activation, joint kinematics, and kinetics during elliptical and stepping movement pattern on a Precor Adaptive Motion Trainer.

    PubMed

    Rogatzki, Matthew J; Kernozek, Thomas W; Willson, John D; Greany, John F; Hong, Di-An; Porcari, John R

    2012-06-01

    Kinematic, kinetic, and electromyography data were collected from the biceps femoris, rectus femoris (RF), gluteus maximus, and erector spinae (ES) during a step and elliptical exercise at a standardized workload with no hand use. Findings depicted 95% greater ankle plantar flexion (p = .01), 29% more knee extension (p = .003), 101% higher peak knee flexor moments (p < .001) 54% greater hip extensor moments (p < .001), 268% greater anterior joint reaction force (p = .009), 37% more RF activation (p < .001), and 200 % more ES activation (p <. 001) for the elliptical motion. Sixteen percent more hip flexion (p < .001), 42% higher knee extensor moments (p < .001), and 54% greater hip flexor moments (p = .041) occurred during the step motion. Biomechanical differences between motions should be considered when planning an exercise regimen. PMID:22808700

  18. Subpectoral biceps tenodesis for bicipital tendonitis with SLAP tear.

    PubMed

    Gupta, Anil K; Chalmers, Peter N; Klosterman, Emma L; Harris, Joshua D; Bach, Bernard R; Verma, Nikhil N; Cole, Brian J; Romeo, Anthony A

    2015-01-01

    The purpose of this study was to evaluate the outcomes of patients undergoing subpectoral biceps tenodesis for bicipital tendonitis with a superior labral anterior-posterior (SLAP) tear. Patients undergoing primary subpectoral biceps tenodesis for arthroscopically confirmed SLAP tears with signs or findings of bicipital tendonitis were included. An independent observer collected data prospectively as part of a data repository, which was then analyzed retrospectively. Primary outcome measures were the American Shoulder and Elbow Surgeons (ASES) score and pain relief via visual analog scale (VAS). Secondary outcome measures included the Simple Shoulder Test (SST), Constant, Single Assessment Numeric Evaluation (SANE), and Short Form 12 (SF-12) scores. Twenty-eight patients with a mean±SD age of 43.7±13.4 years and a mean±SD follow-up of 2.0±1.0 years met inclusion criteria. Workers' compensation was involved with 43% of cases, and 46% of the included patients were manual laborers. Eight (32%) patients were athletes, and 88% of the athletes were overhead athletes. Intraoperatively, 15 (54%) patients had type I SLAP tears, 10 (36%) had type II SLAP tears, 1 (3%) had a type III SLAP tear, and 2 (7%) had type IV SLAP tears. Significant improvements were seen in the following outcome measures pre- vs postoperatively: ASES score (58±23 vs 89±18; P=.001), SST score (6.3±3.6 vs 10.6±3.3; P=.001), SANE score (54±24 vs 88±25; P=.003), VAS score (3.8±2.0 vs 1.1±1.8; P=.001), SF-12 overall score (35±6 vs 42±6; P=.001), and SF-12 physical component score (39±6 vs 50±10; P=.001). Overall satisfaction was excellent in 80% of patients. Subpectoral biceps tenodesis demonstrates excellent clinical outcomes in select patients with SLAP tears. [Orthopedics. 2015; 38(1):e48-e53.].

  19. Initial Performance of Bicep3: A Degree Angular Scale 95 GHz Band Polarimeter

    NASA Astrophysics Data System (ADS)

    Wu, W. L. K.; Ade, P. A. R.; Ahmed, Z.; Alexander, K. D.; Amiri, M.; Barkats, D.; Benton, S. J.; Bischoff, C. A.; Bock, J. J.; Bowens-Rubin, R.; Buder, I.; Bullock, E.; Buza, V.; Connors, J. A.; Filippini, J. P.; Fliescher, S.; Grayson, J. A.; Halpern, M.; Harrison, S. A.; Hilton, G. C.; Hristov, V. V.; Hui, H.; Irwin, K. D.; Kang, J.; Karkare, K. S.; Karpel, E.; Kefeli, S.; Kernasovskiy, S. A.; Kovac, J. M.; Kuo, C. L.; Megerian, K. G.; Netterfield, C. B.; Nguyen, H. T.; O'Brient, R.; Ogburn, R. W.; Pryke, C.; Reintsema, C. D.; Richter, S.; Sorensen, C.; Staniszewski, Z. K.; Steinbach, B.; Sudiwala, R. V.; Teply, G. P.; Thompson, K. L.; Tolan, J. E.; Tucker, C. E.; Turner, A. D.; Vieregg, A. G.; Weber, A. C.; Wiebe, D. V.; Willmert, J.; Yoon, K. W.

    2016-08-01

    Bicep3 is a 550-mm aperture telescope with cold, on-axis, refractive optics designed to observe at the 95-GHz band from the South Pole. It is the newest member of the Bicep/ Keck family of inflationary probes specifically designed to measure the polarization of the cosmic microwave background (CMB) at degree angular scales. Bicep3 is designed to house 1280 dual-polarization pixels, which, when fully populated, totals to ˜ 9× the number of pixels in a single Keck 95-GHz receiver, thus further advancing the Bicep/ Keck program's 95 GHz mapping speed. Bicep3 was deployed during the austral summer of 2014-2015 with nine detector tiles, to be increased to its full capacity of 20 in the second season. After instrument characterization, measurements were taken, and CMB observation commenced in April 2015. Together with multi-frequency observation data from Planck, Bicep2, and the Keck Array, Bicep3 is projected to set upper limits on the tensor-to-scalar ratio to r lesssim 0.03 at 95 % C.L.

  20. BICEP3: a 95GHz refracting telescope for degree-scale CMB polarization

    NASA Astrophysics Data System (ADS)

    Ahmed, Z.; Amiri, M.; Benton, S. J.; Bock, J. J.; Bowens-Rubin, R.; Buder, I.; Bullock, E.; Connors, J.; Filippini, J. P.; Grayson, J. A.; Halpern, M.; Hilton, G. C.; Hristov, V. V.; Hui, H.; Irwin, K. D.; Kang, J.; Karkare, K. S.; Karpel, E.; Kovac, J. M.; Kuo, C. L.; Netterfield, C. B.; Nguyen, H. T.; O'Brient, R.; Ogburn, R. W.; Pryke, C.; Reintsema, C. D.; Richter, S.; Thompson, K. L.; Turner, A. D.; Vieregg, A. G.; Wu, W. L. K.; Yoon, K. W.

    2014-08-01

    Bicep3 is a 550 mm-aperture refracting telescope for polarimetry of radiation in the cosmic microwave background at 95 GHz. It adopts the methodology of Bicep1, Bicep2 and the Keck Array experiments | it possesses sufficient resolution to search for signatures of the inflation-induced cosmic gravitational-wave background while utilizing a compact design for ease of construction and to facilitate the characterization and mitigation of systematics. However, Bicep3 represents a significant breakthrough in per-receiver sensitivity, with a focal plane area 5x larger than a Bicep2/Keck Array receiver and faster optics (f=1:6 vs. f=2:4). Large-aperture infrared-reflective metal-mesh filters and infrared-absorptive cold alumina filters and lenses were developed and implemented for its optics. The camera consists of 1280 dual-polarization pixels; each is a pair of orthogonal antenna arrays coupled to transition-edge sensor bolometers and read out by multiplexed SQUIDs. Upon deployment at the South Pole during the 2014-15 season, Bicep3 will have survey speed comparable to Keck Array 150 GHz (2013), and will signifcantly enhance spectral separation of primordial B-mode power from that of possible galactic dust contamination in the Bicep2 observation patch

  1. Radiative inflation and dark energy RIDEs again after BICEP2

    SciTech Connect

    Bari, Pasquale Di; King, Stephen F.; Merle, Alexander; Luhn, Christoph; Schmidt-May, Angnis E-mail: S.F.King@soton.ac.uk E-mail: A.Merle@soton.ac.uk

    2014-08-01

    Following the ground-breaking measurement of the tensor-to-scalar ratio r=0.20{sup +0.07}{sub -0.05} by the BICEP2 collaboration, we perform a statistical analysis of a model that combines Radiative Inflation with Dark Energy (RIDE) based on the M{sup 2}|Φ|{sup 2}ln(|Φ|{sup 2}/Λ{sup 2}) potential and compare its predictions to those based on the traditional chaotic inflation M{sup 2}|Φ|{sup 2} potential. We find a best-fit value in the RIDE model of r=0.18 as compared to r=0.17 in the chaotic model, with the spectral index being n{sub S}=0.96 in both models.

  2. Quantifying the BICEP2-Planck tension over gravitational waves.

    PubMed

    Smith, Kendrick M; Dvorkin, Cora; Boyle, Latham; Turok, Neil; Halpern, Mark; Hinshaw, Gary; Gold, Ben

    2014-07-18

    The recent BICEP2 measurement of B-mode polarization in the cosmic microwave background (r = 0.2(-0.05)(+0.07)), a possible indication of primordial gravity waves, appears to be in tension with the upper limit from WMAP (r < 0.13 at 95% C.L.) and Planck (r < 0.11 at 95% C.L.). We carefully quantify the level of tension and show that it is very significant (around 0.1% unlikely) when the observed deficit of large-scale temperature power is taken into account. We show that measurements of TE and EE power spectra in the near future will discriminate between the hypotheses that this tension is either a statistical fluke or a sign of new physics. We also discuss extensions of the standard cosmological model that relieve the tension and some novel ways to constrain them. PMID:25083631

  3. Quantifying the BICEP2-Planck tension over gravitational waves.

    PubMed

    Smith, Kendrick M; Dvorkin, Cora; Boyle, Latham; Turok, Neil; Halpern, Mark; Hinshaw, Gary; Gold, Ben

    2014-07-18

    The recent BICEP2 measurement of B-mode polarization in the cosmic microwave background (r = 0.2(-0.05)(+0.07)), a possible indication of primordial gravity waves, appears to be in tension with the upper limit from WMAP (r < 0.13 at 95% C.L.) and Planck (r < 0.11 at 95% C.L.). We carefully quantify the level of tension and show that it is very significant (around 0.1% unlikely) when the observed deficit of large-scale temperature power is taken into account. We show that measurements of TE and EE power spectra in the near future will discriminate between the hypotheses that this tension is either a statistical fluke or a sign of new physics. We also discuss extensions of the standard cosmological model that relieve the tension and some novel ways to constrain them.

  4. Joint analysis of BICEP2/keck array and Planck Data.

    PubMed

    Ade, P A R; Aghanim, N; Ahmed, Z; Aikin, R W; Alexander, K D; Arnaud, M; Aumont, J; Baccigalupi, C; Banday, A J; Barkats, D; Barreiro, R B; Bartlett, J G; Bartolo, N; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A; Benton, S J; Bernard, J-P; Bersanelli, M; Bielewicz, P; Bischoff, C A; Bock, J J; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Brevik, J A; Bucher, M; Buder, I; Bullock, E; Burigana, C; Butler, R C; Buza, V; Calabrese, E; Cardoso, J-F; Catalano, A; Challinor, A; Chary, R-R; Chiang, H C; Christensen, P R; Colombo, L P L; Combet, C; Connors, J; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J-M; Désert, F-X; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dowell, C D; Duband, L; Ducout, A; Dunkley, J; Dupac, X; Dvorkin, C; Efstathiou, G; Elsner, F; Enßlin, T A; Eriksen, H K; Falgarone, E; Filippini, J P; Finelli, F; Fliescher, S; Forni, O; Frailis, M; Fraisse, A A; Franceschi, E; Frejsel, A; Galeotta, S; Galli, S; Ganga, K; Ghosh, T; Giard, M; Gjerløw, E; Golwala, S R; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Gudmundsson, J E; Halpern, M; Hansen, F K; Hanson, D; Harrison, D L; Hasselfield, M; Helou, G; Henrot-Versillé, S; Herranz, D; Hildebrandt, S R; Hilton, G C; Hivon, E; Hobson, M; Holmes, W A; Hovest, W; Hristov, V V; Huffenberger, K M; Hui, H; Hurier, G; Irwin, K D; Jaffe, A H; Jaffe, T R; Jewell, J; Jones, W C; Juvela, M; Karakci, A; Karkare, K S; Kaufman, J P; Keating, B G; Kefeli, S; Keihänen, E; Kernasovskiy, S A; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Knox, L; Kovac, J M; Krachmalnicoff, N; Kunz, M; Kuo, C L; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J-M; Lasenby, A; Lattanzi, M; Lawrence, C R; Leitch, E M; Leonardi, R; Levrier, F; Lewis, A; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Lueker, M; Macías-Pérez, J F; Maffei, B; Maino, D; Mandolesi, N; Mangilli, A; Maris, M; Martin, P G; Martínez-González, E; Masi, S; Mason, P; Matarrese, S; Megerian, K G; Meinhold, P R; Melchiorri, A; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M-A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Moss, A; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nguyen, H T; Nørgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; O'Brient, R; Ogburn, R W; Orlando, A; Pagano, L; Pajot, F; Paladini, R; Paoletti, D; Partridge, B; Pasian, F; Patanchon, G; Pearson, T J; Perdereau, O; Perotto, L; Pettorino, V; Piacentini, F; Piat, M; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Pratt, G W; Prunet, S; Pryke, C; Puget, J-L; Rachen, J P; Reach, W T; Rebolo, R; Reinecke, M; Remazeilles, M; Renault, C; Renzi, A; Richter, S; Ristorcelli, I; Rocha, G; Rossetti, M; Roudier, G; Rowan-Robinson, M; Rubiño-Martín, J A; Rusholme, B; Sandri, M; Santos, D; Savelainen, M; Savini, G; Schwarz, R; Scott, D; Seiffert, M D; Sheehy, C D; Spencer, L D; Staniszewski, Z K; Stolyarov, V; Sudiwala, R; Sunyaev, R; Sutton, D; Suur-Uski, A-S; Sygnet, J-F; Tauber, J A; Teply, G P; Terenzi, L; Thompson, K L; Toffolatti, L; Tolan, J E; Tomasi, M; Tristram, M; Tucci, M; Turner, A D; Valenziano, L; Valiviita, J; Van Tent, B; Vibert, L; Vielva, P; Vieregg, A G; Villa, F; Wade, L A; Wandelt, B D; Watson, R; Weber, A C; Wehus, I K; White, M; White, S D M; Willmert, J; Wong, C L; Yoon, K W; Yvon, D; Zacchei, A; Zonca, A

    2015-03-13

    We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400  deg^{2} patch of sky centered on RA 0 h, Dec. -57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2  μK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B modes at high significance. We fit the single- and cross-frequency power spectra at frequencies ≥150  GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We find strong evidence for dust and no statistically significant evidence for tensor modes. We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally, we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r_{0.05}<0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance. PMID:25815919

  5. Joint analysis of BICEP2/keck array and Planck Data.

    PubMed

    Ade, P A R; Aghanim, N; Ahmed, Z; Aikin, R W; Alexander, K D; Arnaud, M; Aumont, J; Baccigalupi, C; Banday, A J; Barkats, D; Barreiro, R B; Bartlett, J G; Bartolo, N; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A; Benton, S J; Bernard, J-P; Bersanelli, M; Bielewicz, P; Bischoff, C A; Bock, J J; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Brevik, J A; Bucher, M; Buder, I; Bullock, E; Burigana, C; Butler, R C; Buza, V; Calabrese, E; Cardoso, J-F; Catalano, A; Challinor, A; Chary, R-R; Chiang, H C; Christensen, P R; Colombo, L P L; Combet, C; Connors, J; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J-M; Désert, F-X; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dowell, C D; Duband, L; Ducout, A; Dunkley, J; Dupac, X; Dvorkin, C; Efstathiou, G; Elsner, F; Enßlin, T A; Eriksen, H K; Falgarone, E; Filippini, J P; Finelli, F; Fliescher, S; Forni, O; Frailis, M; Fraisse, A A; Franceschi, E; Frejsel, A; Galeotta, S; Galli, S; Ganga, K; Ghosh, T; Giard, M; Gjerløw, E; Golwala, S R; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Gudmundsson, J E; Halpern, M; Hansen, F K; Hanson, D; Harrison, D L; Hasselfield, M; Helou, G; Henrot-Versillé, S; Herranz, D; Hildebrandt, S R; Hilton, G C; Hivon, E; Hobson, M; Holmes, W A; Hovest, W; Hristov, V V; Huffenberger, K M; Hui, H; Hurier, G; Irwin, K D; Jaffe, A H; Jaffe, T R; Jewell, J; Jones, W C; Juvela, M; Karakci, A; Karkare, K S; Kaufman, J P; Keating, B G; Kefeli, S; Keihänen, E; Kernasovskiy, S A; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Knox, L; Kovac, J M; Krachmalnicoff, N; Kunz, M; Kuo, C L; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J-M; Lasenby, A; Lattanzi, M; Lawrence, C R; Leitch, E M; Leonardi, R; Levrier, F; Lewis, A; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Lueker, M; Macías-Pérez, J F; Maffei, B; Maino, D; Mandolesi, N; Mangilli, A; Maris, M; Martin, P G; Martínez-González, E; Masi, S; Mason, P; Matarrese, S; Megerian, K G; Meinhold, P R; Melchiorri, A; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M-A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Moss, A; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nguyen, H T; Nørgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; O'Brient, R; Ogburn, R W; Orlando, A; Pagano, L; Pajot, F; Paladini, R; Paoletti, D; Partridge, B; Pasian, F; Patanchon, G; Pearson, T J; Perdereau, O; Perotto, L; Pettorino, V; Piacentini, F; Piat, M; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Pratt, G W; Prunet, S; Pryke, C; Puget, J-L; Rachen, J P; Reach, W T; Rebolo, R; Reinecke, M; Remazeilles, M; Renault, C; Renzi, A; Richter, S; Ristorcelli, I; Rocha, G; Rossetti, M; Roudier, G; Rowan-Robinson, M; Rubiño-Martín, J A; Rusholme, B; Sandri, M; Santos, D; Savelainen, M; Savini, G; Schwarz, R; Scott, D; Seiffert, M D; Sheehy, C D; Spencer, L D; Staniszewski, Z K; Stolyarov, V; Sudiwala, R; Sunyaev, R; Sutton, D; Suur-Uski, A-S; Sygnet, J-F; Tauber, J A; Teply, G P; Terenzi, L; Thompson, K L; Toffolatti, L; Tolan, J E; Tomasi, M; Tristram, M; Tucci, M; Turner, A D; Valenziano, L; Valiviita, J; Van Tent, B; Vibert, L; Vielva, P; Vieregg, A G; Villa, F; Wade, L A; Wandelt, B D; Watson, R; Weber, A C; Wehus, I K; White, M; White, S D M; Willmert, J; Wong, C L; Yoon, K W; Yvon, D; Zacchei, A; Zonca, A

    2015-03-13

    We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400  deg^{2} patch of sky centered on RA 0 h, Dec. -57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2  μK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B modes at high significance. We fit the single- and cross-frequency power spectra at frequencies ≥150  GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We find strong evidence for dust and no statistically significant evidence for tensor modes. We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally, we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r_{0.05}<0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance.

  6. Isocurvature perturbations and tensor mode in light of Planck and BICEP2

    SciTech Connect

    Kawasaki, Masahiro; Yokoyama, Shuichiro; Sekiguchi, Toyokazu; Takahashi, Tomo E-mail: toyokazu.sekiguchi@helsinki.fi E-mail: shu@icrr.u-tokyo.ac.jp

    2014-08-01

    We investigate the degeneracy of the isocurvature perturbations and the primordial gravitational waves, by using recent observations of the cosmic microwave background (CMB) reported by Planck and BICEP2 collaborations. We show that the tension in the bound on the tensor-to-scalar ratio r between Planck and BICEP2 can be resolved by introducing the anti-correlated isocurvature perturbations. Quantitatively, we find that with the anti-correlated isocurvature perturbations the constraints on r from Planck alone and BICEP2 results can be consistent at 68 % C.L.

  7. A newly discovered muscle: The tensor of the vastus intermedius.

    PubMed

    Grob, K; Ackland, T; Kuster, M S; Manestar, M; Filgueira, L

    2016-03-01

    The quadriceps femoris is traditionally described as a muscle group composed of the rectus femoris and the three vasti. However, clinical experience and investigations of anatomical specimens are not consistent with the textbook description. We have found a second tensor-like muscle between the vastus lateralis (VL) and the vastus intermedius (VI), hereafter named the tensor VI (TVI). The aim of this study was to clarify whether this intervening muscle was a variation of the VL or the VI, or a separate head of the extensor apparatus. Twenty-six cadaveric lower limbs were investigated. The architecture of the quadriceps femoris was examined with special attention to innervation and vascularization patterns. All muscle components were traced from origin to insertion and their affiliations were determined. A TVI was found in all dissections. It was supplied by independent muscular and vascular branches of the femoral nerve and lateral circumflex femoral artery. Further distally, the TVI combined with an aponeurosis merging separately into the quadriceps tendon and inserting on the medial aspect of the patella. Four morphological types of TVI were distinguished: Independent-type (11/26), VI-type (6/26), VL-type (5/26), and Common-type (4/26). This study demonstrated that the quadriceps femoris is architecturally different from previous descriptions: there is an additional muscle belly between the VI and VL, which cannot be clearly assigned to the former or the latter. Distal exposure shows that this muscle belly becomes its own aponeurosis, which continues distally as part of the quadriceps tendon.

  8. Effects of unilateral and bilateral lower-body heavy resistance exercise on muscle activity and testosterone responses.

    PubMed

    Jones, Margaret T; Ambegaonkar, Jatin P; Nindl, Bradley C; Smith, Jeffrey A; Headley, Samuel A

    2012-04-01

    Unilateral and bilateral lower-body heavy resistance exercises (HREs) are used for strength training. Little research has examined whether muscle activation and testosterone (TES) responses differ between these exercises. Our purpose was to compare the effects of unilateral and bilateral lower-body HRE on muscle activity using surface electromyography (sEMG) and TES concentrations. Ten resistance-trained, college-aged male athletes (football, track and field) completed 5 testing sessions in which bilateral (back squat [BS]) and unilateral (pitcher squat [PS]) exercises were performed using a counterbalanced design. Sessions 1 and 2 determined estimated maximum strength (10 repetition maximum [10RM]) in the BS and PS. During testing session 3, muscle activation (sEMG) was measured in the right vastus lateralis, biceps femoris, gluteus maximus, and erector spinae (ES) during both BS and PS (stance leg) exercises. In sessions 4 and 5, total TES concentrations (nanomoles per liter) were measured via blood draws at baseline (preexercise), 0, 5, 10, 15, and 30 minutes postexercise after 4 sets of 10 repetitions at the 10RM. Separate repeated-measures analyses of variance examined differences in sEMG and TES between BS and PS (p < 0.05). The sEMG amplitudes were similar (p = 0.80) for BS (0.22 ± 0.06 mV) and PS (0.20 ± 0.07 mV). The TES responses were also similar (p = 0.15) between BS (21.8 ± 6.9 nmol·L(-1)) and PS (26.2 ± 10.1 nmol·L(-1)). The similar lower limb and back sEMG and TES responses may indicate that the neuromuscular and hormonal demands were comparable for both the BS and PS exercises despite the absolute work being less in the PS. The PS exercise may be an effective method for including unilateral exercise into lower-body resistance training when designing training programs for ground-based activities.

  9. Does the rectus femoris nerve block improve knee recurvatum in adult stroke patients? A kinematic and electromyographic study.

    PubMed

    Gross, R; Delporte, L; Arsenault, L; Revol, P; Lefevre, M; Clevenot, D; Boisson, D; Mertens, P; Rossetti, Y; Luauté, J

    2014-02-01

    Knee recurvatum (KR) during gait is common in hemiplegic patients. Quadriceps spasticity has been postulated as a cause of KR in this population. The aim of this study was to assess the role of rectus femoris spasticity in KR by using selective motor nerve blocks of the rectus femoris nerve in hemiparetic stroke patients. The data from six adult, post-stroke hemiplegic patients who underwent a rectus femoris nerve block for a stiff-knee gait were retrospectively analyzed. An extensive clinical and functional evaluation was performed and gait was assessed by motion analysis (kinematic, kinetic and electromyographic parameters) before and during the block realized using 2% lidocaine injected under a neurostimulation and ultrasonographic targeting procedure. The main outcome measures were the peak knee extension in stance and peak knee extensor moment obtained during gait analysis. No serious adverse effect of the nerve block was observed. The block allowed a reduction of rectus femoris overactivity in all patients. Peak knee extension and extensor moment in stance did not improve in any patient, but peak knee flexion during the swing phase was significantly higher after block (mean: 31.2° post, 26.4 pre, p < 0.05). Our results provide arguments against the hypothesis that the spasticity of the rectus femoris contributes to KR. PMID:24286615

  10. Effects of a multichannel dynamic functional electrical stimulation system on hemiplegic gait and muscle forces.

    PubMed

    Qian, Jing-Guang; Rong, Ke; Qian, Zhenyun; Wen, Chen; Zhang, Songning

    2015-11-01

    [Purpose] The purpose of the study was to design and implement a multichannel dynamic functional electrical stimulation system and investigate acute effects of functional electrical stimulation of the tibialis anterior and rectus femoris on ankle and knee sagittal-plane kinematics and related muscle forces of hemiplegic gait. [Subjects and Methods] A multichannel dynamic electrical stimulation system was developed with 8-channel low frequency current generators. Eight male hemiplegic patients were trained for 4 weeks with electric stimulation of the tibia anterior and rectus femoris muscles during walking, which was coupled with active contraction. Kinematic data were collected, and muscle forces of the tibialis anterior and rectus femoris of the affected limbs were analyzed using a musculoskelatal modeling approach before and after training. A paired sample t-test was used to detect the differences between before and after training. [Results] The step length of the affected limb significantly increased after the stimulation was applied. The maximum dorsiflexion angle and maximum knee flexion angle of the affected limb were both increased significantly during stimulation. The maximum muscle forces of both the tibia anterior and rectus femoris increased significantly during stimulation compared with before functional electrical stimulation was applied. [Conclusion] This study established a functional electrical stimulation strategy based on hemiplegic gait analysis and musculoskeletal modeling. The multichannel functional electrical stimulation system successfully corrected foot drop and altered circumduction hemiplegic gait pattern.

  11. Mimetic F(R) inflation confronted with Planck and BICEP2/Keck Array data

    NASA Astrophysics Data System (ADS)

    Odintsov, S. D.; Oikonomou, V. K.

    2016-05-01

    In this paper we demonstrate that in the context of mimetic F(R) gravity with Lagrange multiplier, it is possible to realize cosmologies which are compatible with the recent BICEP2/Keck Array data. We provide some characteristic examples for which the predicted scalar to tensor ratio can be quite smaller in comparison to the upper limit imposed by the BICEP2/Keck Array observations.

  12. The Painful Long Head of the Biceps Brachii: Nonoperative Treatment Approaches.

    PubMed

    Wilk, Kevin E; Hooks, Todd R

    2016-01-01

    The long head of the biceps has garnered increased attention and interest due to the high prevalence of pain that can be a primary condition or occur secondary to shoulder dysfunction. The successful treatment of biceps tendinopathy is dependent on an accurate diagnosis and recognizing all causative factors. The treatment program will be individualized with a rehabilitation program designed to restore strength and flexibility and restore normal tendon mechanics.

  13. The association between hip muscle cross-sectional area, muscle strength, and bone mineral density.

    PubMed

    Ahedi, Harbeer; Aitken, Dawn; Scott, David; Blizzard, Leigh; Cicuttini, Flavia; Jones, Graeme

    2014-07-01

    Studies examining the association between muscle size, muscle strength, and bone mineral density (BMD) are limited. Thus, this study aimed to describe the association between hip muscles cross-sectional area (CSA), muscle strength, and BMD of the hip and spine. A total of 321 subjects from the Tasmanian Older Adult Cohort study with a right hip MRI scan conducted between 2004 and 2006 were included. Hip muscles were measured on MR images by OsiriX (Geneva) software measuring maximum muscle CSA (cm(2)) of gluteus maximus, obturator externus, gemelli, quadratus femoris, piriformis, pectineus, sartorius, and iliopsoas. Dual-energy X-ray absorptiometry measured total hip, femoral neck, and spine BMD, and lower limb muscle strength was assessed by dynamometer. Muscle CSA of the hip flexors (pectineus, sartorius, and iliopsoas) and the hip rotators, obturator externus, and quadratus femoris were associated with both total hip and femoral neck BMD (all p < 0.05). The associations between CSA of pectineus and sartorius and BMD were stronger in women (p = 0.01-0.001) compared to men (p = 0.12-0.54). Additionally, only gemelli CSA was associated with BMD of the spine (p = 0.002). Gluteus maximus and piriformis showed no relationship with BMD. CSA of most hip muscles (except gluteus maximus and gemelli) were positively associated with leg strength (p = 0.02 to <0.001). Lastly, leg strength was weakly associated with BMD (p = 0.11-0.007). Hip muscle CSA, and to a lesser extent muscle strength, were positively associated with hip BMD. These data suggest that both higher muscle mass and strength may contribute to the maintenance of bone mass and prevention of disease progression in older adults. PMID:24829114

  14. Voluntary activation failure is detectable in some myositis patients with persisting quadriceps femoris weakness: an observational study

    PubMed Central

    Molloy, Catherine B; Al-Omar, Ahmed O; Edge, Kathryn T; Cooper, Robert G

    2006-01-01

    This cross-sectional, observational study was undertaken to examine whether voluntary activation failure could contribute to the persisting weakness observed in some patients with treated idiopathic inflammatory myositis. In 20 patients with myositis of more than six months' duration (5 males, 15 females; mean [± 1 SD] age 53 [11] years) and 102 normal subjects (44 males, 58 females; mean age 32 [8] years), isometric maximum voluntary contractions (MVCs) of the dominant quadriceps femoris (QF) were quantified. Absolute MVC results of normal subjects and patients were then normalised with respect to lean body mass (force per units of lean body mass), giving a result in Newtons per kilogram. Based on mass-normalised force data of normal subjects, patients were arbitrarily stratified into "weak" and "not weak" subgroups. During further MVC attempts, the "twitch interpolation" technique was used to assess whether the QF voluntary activation of patients was complete. This technique relies on the fact that, because muscle activation is incomplete during submaximal voluntary contractions, electrical stimulation of the muscle can induce force increments superimposed on the submaximal voluntary force being generated. No between-gender differences were seen in the mass-normalised MVC results of healthy subjects, so the gender-combined results of 6.6 (1.5) N/kg were used for patient stratification. No between-gender difference was found for mass-normalised MVCs in patients: males 5.4 (3.2) and females 3.0 (1.7) N/kg (p > 0.05). Mass-normalised MVCs of male patients were as great as those of normal subjects (p > 0.05), but mass-normalised MVCs of female patients were significantly smaller than those of the normal subjects (p < 0.001). Only one of the six "not weak" patients exhibited interpolated twitches during electrical stimulation, but six of the 14 "weak" patients did, the biggest twitches being seen in the weakest patient. That interpolated twitches can be induced in

  15. Corticospinal excitability of the biceps brachii is higher during arm cycling than an intensity-matched tonic contraction.

    PubMed

    Forman, Davis; Raj, Amita; Button, Duane C; Power, Kevin E

    2014-09-01

    Human studies have not assessed corticospinal excitability of an upper-limb prime mover during arm cycling. The purpose of the present study was to determine whether supraspinal and/or spinal motoneuron excitability of the biceps brachii was different between arm cycling and an intensity-matched tonic contraction. We hypothesized that spinal motoneuron excitability would be higher during arm cycling than an intensity-matched tonic contraction. Supraspinal and spinal motoneuron excitability were assessed using transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid electrical stimulation (TMES) of the corticospinal tract, respectively. TMS-induced motor-evoked potentials (MEPs) and TMES-induced cervicomedullary-evoked potentials (CMEPs) were assessed at three separate positions (3, 6, and 12 o'clock relative to a clock face) during arm cycling and an intensity-matched tonic contraction. MEP amplitudes were 7.2 and 8.8% maximum amplitude of the compound muscle action potential (Mmax) larger during arm cycling compared with a tonic contraction at the 3 (P < 0.001) and 6 o'clock (P < 0.001) positions, respectively. There was no difference between tasks during elbow extension (12 o'clock). CMEP amplitudes were 5.2% Mmax larger during arm cycling compared with a tonic contraction at the 3 o'clock position (P < 0.001) with no differences seen at midflexion (6 o'clock) or extension (12 o'clock). The data indicate an increase in the excitability of corticospinal neurons, which ultimately project to biceps brachii during the elbow flexion portion of arm cycling, and increased spinal motoneuron excitability at the onset of elbow flexion during arm cycling. We conclude that supraspinal and spinal motoneuron excitability are phase- and task-dependent. PMID:24899677

  16. A cadaver knee simulator to evaluate the biomechanics of rectus femoris transfer.

    PubMed

    Anderson, Michael C; Brown, Nicholas A T; Bachus, Kent N; Macwilliams, Bruce A

    2009-07-01

    A cadaver knee simulator has been developed to model surgical transfer of the rectus femoris. The simulator allows knee specimens six degrees of freedom and is capable of modeling both the swing and stance phases of human gait. Experiments were conducted using a mechanical hinge analog of the knee to verify that time, flexion angle, and knee extension force measurements recorded when using the simulator were not influenced by its design or operation. A ballistic double pendulum model was used to model the swing phase of gait, and the contributions of hip and ankle torques and hamstrings cocontraction were included when modeling the stance phase of gait. When modeling swing, range of motion and time to peak knee flexion in swing for the hinge knee were similar to those of in vivo test subjects. Measurements of hinge knee extension force when modeling stance under various biomechanical conditions matched those predicted using an analytical model. Future studies using cadaver knee specimens will apply techniques described in this paper to further our understanding of changes in knee biomechanics caused by rectus femoris transfer surgery. PMID:19403312

  17. Axion cold dark matter in view of BICEP2 results.

    PubMed

    Gondolo, Paolo; Visinelli, Luca

    2014-07-01

    The properties of axions that constitute 100% of cold dark matter (CDM) depend on the tensor-to-scalar ratio r at the end of inflation. If r=0.20(-0.05)(+0.07) as reported by the BICEP2 Collaboration, then "half" of the CDM axion parameter space is ruled out. Namely, in the context of single-field slow-roll inflation, for axions to be 100% of the CDM, the Peccei-Quinn symmetry must be broken after the end of inflation, so that axion nonadiabatic primordial fluctuations are compatible with observational constraints. The cosmic axion density is then independent of the tensor-to-scalar ratio r, and the axion mass is expected to be in a narrow range that, however, depends on the cosmological model before primordial nucleosynthesis. In the standard Lambda CDM cosmology, the CDM axion mass range is ma=(71±2  μeV)(αdec+1)6/7, where αdec is the fractional contribution to the cosmic axion density from decays of axionic strings and walls.

  18. Interprofessional analysis of esthetical deformity from long head biceps tenotomy

    PubMed Central

    Almeida, Alexandre; Valin, Márcio Rangel; Lotti, Cleber; de Almeida, Nayvaldo Couto; Agostini, Ana Paula

    2015-01-01

    OBJECTIVE: To evaluate the perception of an esthetical deformity resultant from arthroscopic long head biceps (LHB) tenotomy according to the degree of experience of the assisting professional. METHODS: 120 patients submitted to shoulder surgery were photographed and photos were mounted in a PowerPoint presentation. Three shoulder specialist surgeons, three generalist orthopedic surgeons and three graduated residents analyzed the presentation. RESULTS: On all patients we observed most agreement among the shoulder specialists. When just the patients with LHB tenotomy were analyzed, the specialists agreed moderately, the generalists had small agreement and the residents, a poor one. Analyzing patients with BMI < 30, there was major agreement between the specialists, while the generalists and residents had poor agreement. Analyzing patients with BMI ≥ 30, the generalists had small kappa agreement, while the specialists and residents had no agreement. CONCLUSIONS: The perception of an esthetical deformity regarding a LHB tenotomy did not have significant agreement between different level of professionals, even though the specialists showed similar perception on tenotomy patients. The evaluation of obese patients lowered the agreement on the three groups of professionals. Level of Evidence III. Case Control Study. PMID:26207087

  19. Axion cold dark matter in view of BICEP2 results.

    PubMed

    Gondolo, Paolo; Visinelli, Luca

    2014-07-01

    The properties of axions that constitute 100% of cold dark matter (CDM) depend on the tensor-to-scalar ratio r at the end of inflation. If r=0.20(-0.05)(+0.07) as reported by the BICEP2 Collaboration, then "half" of the CDM axion parameter space is ruled out. Namely, in the context of single-field slow-roll inflation, for axions to be 100% of the CDM, the Peccei-Quinn symmetry must be broken after the end of inflation, so that axion nonadiabatic primordial fluctuations are compatible with observational constraints. The cosmic axion density is then independent of the tensor-to-scalar ratio r, and the axion mass is expected to be in a narrow range that, however, depends on the cosmological model before primordial nucleosynthesis. In the standard Lambda CDM cosmology, the CDM axion mass range is ma=(71±2  μeV)(αdec+1)6/7, where αdec is the fractional contribution to the cosmic axion density from decays of axionic strings and walls. PMID:25032919

  20. Biceps instability and Slap type II tear in overhead athletes.

    PubMed

    Osti, Leonardo; Soldati, Francesco; Cheli, Andrea; Pari, Carlotta; Massari, Leo; Maffulli, Nicola

    2012-10-01

    Type II lesions are common lesions encountered in overhead athletes with controversies arising in term of timing for treatment, surgical approach, rehabilitation and functional results. The aim of our study was to evaluate the outcomes of arthroscopic repair of type II SLAP tears in overhead athletes, focusing on the time elapsed from diagnosis and treatment, time needed to return to sport, rate of return to sport and to previous level of performance, providing an overview concerning evidence for the effectiveness of different surgical approaches to type II SLAP tears in overhead athletes. A internet search on peer reviewed Journal from 1990, first descriprion of this pathology, to 2012, have been conducted evaluating the outcomes for both isolated Slap II tear overhead athletes and those who presented associated lesions treated. The results have been analyzed according to the scale reported focusing on return to sport and level of activity. Apart from a single study, non prospective level I and II studies were detected. Return to play at the same level ranged form 22% to 94% with different range of technique utilized with the majority of the authors recommending the fixation of these lesions but biceps tenodesis can lead to higher satisfaction racte when directly compated to the anchor fixation. Associated pathologies such as partial or full tickness rotator cuff tear did not clearly affect the outcomes and complications rate. There is no consensus regarding timing and treatment for type II SLAP, especially in overhead athletes who need to regain a high level of performance.

  1. Upper-extremity thrombosis in a patient after biceps tenodesis.

    PubMed

    Offoha, Roosevelt U; Garzon-Muvdi, Juan; Streiff, Michael B; McFarland, Edward G

    2014-12-01

    Deep venous thrombosis (DVT) of the upper extremity is uncommon compared with DVT of the lower extremity. Exertional DVT has been described in some athletes, especially in the dominant arm of baseball players. It is important for health care professionals to recognize the signs and symptoms of upper-extremity DVT, which can occur after exertion or after surgery of the upper extremity. Superficial venous thrombosis is also very uncommon in the upper extremity. This article describes a case of superficial venous thrombosis that mimicked DVT in the surgical (right) arm of a recreational baseball player after suprapectoral biceps tenodesis for a painful superior labrum anterior-posterior lesion. Although the superficial venous system of the upper arm has frequent connections to the deeper basilar system, it is uncommon for superficial venous thrombosis to occur concurrently with DVT. It is important for clinicians to understand the distinction between superficial venous thrombosis and DVT in the upper extremity because the physical findings, treatment, and prognosis for these 2 entities differ in the following ways: (1) superficial venous thrombosis may be accompanied by a cord, but DVT is associated with more generalized swelling; (2) superficial venous thrombosis requires symptomatic treatment only, whereas DVT requires anticoagulation; and (3) superficial venous thrombosis typically resolves with few sequelae, whereas upper-extremity DVT increases the risk of future DVT.

  2. Reconstructing the local potential of inflation with BICEP2 data

    SciTech Connect

    Ma, Yin-Zhe; Wang, Yi E-mail: yw366@cam.ac.uk

    2014-09-01

    We locally reconstruct the inflationary potential by using the current constraints on r and n{sub s} from BICEP2 data. Assuming small and negligible α{sub s}, the inflationary potential is approximately linear in Δφ∼ M{sub pl} range but becomes non-linear in Δφ∼ 10 M{sub pl} range. However if we vary the value of α{sub s} within the range given by constraints from Planck measurement, the local reconstruction is only valid in the range of Δφ∼ 0.4 M{sub pl}, which challenges the inflationary background from the point of view of effective field theory. We show that, within the range of Δ φ ∼ 0.4 M{sub pl}, the inflation potential can be precisely reconstructed. With the current reconstruction, we show that V(φ) ∼ φ{sup 2} and φ{sup 3} are consistent, while φ model is ruled out by 95% confidence level of the reconstructed range of potential. This sets up a strong limit of large-field inflation models.

  3. Actions of Two Bi-Articular Muscles of the Lower Extremity: A Review

    PubMed Central

    Landin, Dennis; Thompson, Melissa; Reid, Meghan

    2016-01-01

    The extremities of the human body contain several bi-articular muscles. The actions produced by muscles at the joints they cross are greatly influenced by joint moment arms and muscle length. These factors are dynamic and subject to change as joint angles are altered. Therefore, to more completely understand the actions of such muscles, the angles of both joints must be manipulated. This report reviews investigations, which have explored the actions of two bi-articular muscles of the lower extremities (gastrocnemius and rectus femoris) as the joints they cross are moved into various combinations of angles. The findings have both clinical and physical performance ramifications. PMID:27298656

  4. Toward an understanding of foreground emission in the BICEP2 region

    SciTech Connect

    Flauger, Raphael; Hill, J. Colin; Spergel, David N. E-mail: jch@astro.princeton.edu

    2014-08-01

    BICEP2 has reported the detection of a degree-scale B-mode polarization pattern in the Cosmic Microwave Background (CMB) and has interpreted the measurement as evidence for primordial gravitational waves. Motivated by the profound importance of the discovery of gravitational waves from the early Universe, we examine to what extent a combination of Galactic foregrounds and lensed E-modes could be responsible for the signal. We reanalyze the BICEP2 results and show that the 100 ×150 GHz and 150 ×150 GHz data are consistent with a cosmology with r=0.2 and negligible foregrounds, but also with a cosmology with r=0 and a significant dust polarization signal. We give independent estimates of the dust polarization signal in the BICEP2 region using a number of different approaches: (1) data-driven models based on Planck 353 GHz intensity, polarization fractions inferred from the same Planck data used by the BICEP2 team but corrected for CMB and CIB contributions, and polarization angles from starlight polarization data or the Planck sky model; (2) the same set of pre-Planck models used by the BICEP2 team but taking into account the higher polarization fractions observed in the CMB- and CIB-corrected map; (3) a measurement of neutral hydrogen gas column density N{sub HI} in the BICEP2 region combined with an extrapolation of a relation between HI column density and dust polarization derived by Planck; and (4) a dust polarization map based on digitized Planck data, which we only use as a final cross-check. While these approaches are consistent with each other, the expected amplitude of the dust polarization power spectrum remains uncertain by about a factor of three. The lower end of the prediction leaves room for a primordial contribution, but at the higher end the dust in combination with the standard CMB lensing signal could account for the BICEP2 observations, without requiring the existence of primordial gravitational waves. By measuring the cross-correlations between

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

    PubMed

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

    1999-09-01

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

  6. The muscle activation patterns of lower limb during stair climbing at different backpack load.

    PubMed

    Yali, Han; Aiguo, Song; Haitao, Gao; Songqing, Zhu

    2015-01-01

    Stair climbing under backpack load condition is a challenging task. Understanding muscle activation patterns of lower limb during stair climbing with load furthers our understanding of the factors involved in joint pathology and the effects of treatment. At the same time, stair climbing under backpack load requires adjustments of muscle activations and increases joint moment compared to level walking, which with muscle activation patterns are altered as a result of using an assistive technology, such as a wearable exoskeleton leg for human walking power augmentation. Therefore, the aim of this study was to analyze lower limb muscles during stair climbing under different backpack load. Nine healthy volunteers ascended a four-step staircase at different backpack load (0 kg, 10 kg, 20 kg, 30 kg). Electromyographic (EMG) signals were recorded from four lower limb muscles (gastrocnemius, tibialis anterior, hamstring, rectus femoris). The results showed that muscle activation amplitudes of lower limb increase with increasing load during stair climbing, the maximum RMS of gastrocnemius are greater than tibialis anterior, hamstring and rectus femoris whether stair climbing or level walking under the same load condition. However, the maximum RMS of hamstring are smaller than gastrocnemius, tibialis anterior and rectus femoris. The study of muscle activation under different backpack load during stair climbing can be used to design biomechanism and explore intelligent control based on EMG for a wearable exoskeleton leg for human walking power augmentation. PMID:26899302

  7. Optimizing Muscle Parameters in Musculoskeletal Modeling Using Monte Carlo Simulations

    NASA Technical Reports Server (NTRS)

    Hanson, Andrea; Reed, Erik; Cavanagh, Peter

    2011-01-01

    Astronauts assigned to long-duration missions experience bone and muscle atrophy in the lower limbs. The use of musculoskeletal simulation software has become a useful tool for modeling joint and muscle forces during human activity in reduced gravity as access to direct experimentation is limited. Knowledge of muscle and joint loads can better inform the design of exercise protocols and exercise countermeasure equipment. In this study, the LifeModeler(TM) (San Clemente, CA) biomechanics simulation software was used to model a squat exercise. The initial model using default parameters yielded physiologically reasonable hip-joint forces. However, no activation was predicted in some large muscles such as rectus femoris, which have been shown to be active in 1-g performance of the activity. Parametric testing was conducted using Monte Carlo methods and combinatorial reduction to find a muscle parameter set that more closely matched physiologically observed activation patterns during the squat exercise. Peak hip joint force using the default parameters was 2.96 times body weight (BW) and increased to 3.21 BW in an optimized, feature-selected test case. The rectus femoris was predicted to peak at 60.1% activation following muscle recruitment optimization, compared to 19.2% activation with default parameters. These results indicate the critical role that muscle parameters play in joint force estimation and the need for exploration of the solution space to achieve physiologically realistic muscle activation.

  8. BICEP2/Keck Array. VII. Matrix Based E/B Separation Applied to Bicep2 and the Keck Array

    NASA Astrophysics Data System (ADS)

    BICEP2 Collaboration; Keck Array Collaboration; Ade, P. A. R.; Ahmed, Z.; Aikin, R. W.; Alexander, K. D.; Barkats, D.; Benton, S. J.; Bischoff, C. A.; Bock, J. J.; Bowens-Rubin, R.; Brevik, J. A.; Buder, I.; Bullock, E.; Buza, V.; Connors, J.; Crill, B. P.; Duband, L.; Dvorkin, C.; Filippini, J. P.; Fliescher, S.; Grayson, J.; Halpern, M.; Harrison, S.; Hildebrandt, S. R.; Hilton, G. C.; Hui, H.; Irwin, K. D.; Kang, J.; Karkare, K. S.; Karpel, E.; Kaufman, J. P.; Keating, B. G.; Kefeli, S.; Kernasovskiy, S. A.; Kovac, J. M.; Kuo, C. L.; Leitch, E. M.; Lueker, M.; Megerian, K. G.; Namikawa, T.; Netterfield, C. B.; Nguyen, H. T.; O'Brient, R.; Ogburn, R. W., IV; Orlando, A.; Pryke, C.; Richter, S.; Schwarz, R.; Sheehy, C. D.; Staniszewski, Z. K.; Steinbach, B.; Sudiwala, R. V.; Teply, G. P.; Thompson, K. L.; Tolan, J. E.; Tucker, C.; Turner, A. D.; Vieregg, A. G.; Weber, A. C.; Wiebe, D. V.; Willmert, J.; Wong, C. L.; Wu, W. L. K.; Yoon, K. W.

    2016-07-01

    A linear polarization field on the sphere can be uniquely decomposed into an E-mode and a B-mode component. These two components are analytically defined in terms of spin-2 spherical harmonics. Maps that contain filtered modes on a partial sky can also be decomposed into E-mode and B-mode components. However, the lack of full sky information prevents orthogonally separating these components using spherical harmonics. In this paper, we present a technique for decomposing an incomplete map into E and B-mode components using E and B eigenmodes of the pixel covariance in the observed map. This method is found to orthogonally define E and B in the presence of both partial sky coverage and spatial filtering. This method has been applied to the Bicep2 and the Keck Array maps and results in reducing E to B leakage from ΛCDM E-modes to a level corresponding to a tensor-to-scalar ratio of r\\lt 1× {10}-4.

  9. Muscle changes in ankylosing spondylitis.

    PubMed

    Hopkins, G O; McDougall, J; Mills, K R; Isenberg, D A; Ebringer, A

    1983-08-01

    Muscle biopsy of the quadriceps femoris was carried out in 20 patients with classical ankylosing spondylitis (AS). Histological and histochemical studies revealed changes in all biopsies to a varying degree. Central migration of nuclei was present in 80%, reduced fibre size with some atrophy in 40%, localized reaction to acid phosphatase in 75% and a peripheral condensation of reaction product to NADH-TR stain in 55% of biopsies. Furthermore 14 out of 16 patients, whose quadriceps strength was measured, were found to be below the predicted values, when compared to healthy controls of similar weight, and quantitative surface electromyography in 10 showed lower mean power frequency than in controls. A raised plasma creatine kinase was found in only two patients. It is concluded that muscle changes occur in AS and these may account for some of the clinical features of the disease.

  10. Subcutaneous injection of Mycobacterium ulcerans causes necrosis, chronic inflammatory response and fibrosis in skeletal muscle.

    PubMed

    Houngbédji, Mabèrou Germain; Boissinot, Maurice; Bergeron, G Michel; Frenette, Jérôme

    2008-10-01

    Mycobacterium ulcerans (M. ulcerans) causes Buruli ulcer, a very debilitating disease that affects the skin and other tissues. The disease occurs mainly in children in sub-Sahara Africa. While contracture, fibrosis and functional limitation of range of motion are frequent complications of Buruli ulcer, no fundamental or clinical studies have investigated the impact of M. ulcerans infections on skeletal muscle. In the present study, we subcutaneously infected mice in the proximity of the right biceps muscle to evaluate the histological, biochemical and functional impact of M. ulcerans on skeletal muscles. The concentration of mast cells decreased but the number of neutrophils and macrophages increased steadily in proximate-infected biceps muscles. Pro- and anti-inflammatory cytokines as well as fibrogenic growth factor mRNA also increased. Significantly more membrane damage and fibrosis occurred in proximate-infected biceps muscles than in control and sham muscles. Passive biomechanical testing also revealed that the presence of M. ulcerans increased muscle stiffness. These findings show for the first time that M. ulcerans can induce local and chronic inflammatory responses in skeletal muscles that are associated with muscle fiber damage and fibrosis.

  11. Event-related differences in the cross-sectional areas and torque generation capabilities of quadriceps femoris and hamstrings in male high school athletes.

    PubMed

    Hoshikawa, Yoshihiro; Muramatsu, Masataka; Iida, Tomomi; Uchiyama, Akiko; Nakajima, Yoshiharu; Kanehisa, Hiroaki

    2010-01-01

    This study investigated the event-related differences in the cross-sectional areas (CSAs) and torque generation capabilities of the quadriceps femoris (QF) and hamstrings (HAM) in male high school athletes. Subjects were soccer players (n=32), volleyball players (21), rowers (29), karate athletes (18), sumo wrestlers (15), sprinters (22), throwers (16), and nonathletes (20). The CSAs of QF and HAM at the mid-thigh were determined using magnetic resonance imaging. In addition, isokinetic torques during knee extension and flexion were determined at a pre-set velocity of 1.05 rad/s. The CSAs of the two muscle groups and torques developed in the two motions were significantly related to the two-third power of lean body mass (LBM(2/3)) and the product of CSA and femur length (CSA*fl), calculated as an index of muscle volume, respectively. CSA relative to LBM(2/3) for QF did not differ among the groups, but that for HAM was higher in sprinters, soccer players, throwers, and karate athletes than in sumo wrestlers, rowers, volleyball players, and nonathletes. Knee extension torque relative to the CSA*fl of QF was higher in karate athletes, soccer players, and rowers than in nonathletes, but the corresponding value for knee flexion did not differ among groups. Thus, the present study indicated that, at least in male high school athletes, the event-related differences in LBM and the muscularity of QF and HAM produced the corresponding differences in the CSAs of the reciprocal muscle groups and knee extension and flexion torques, respectively. However, specific profiles related to competitive and/or training styles exist in HAM CSA and knee extension torque, which cannot be explained by the magnitude of LBM and QF CSA, respectively. PMID:20453429

  12. Analysis of upper arm muscle activation using surface electromyography signals during drum playing

    PubMed Central

    Chong, Hyun Ju; Kwon, Chun-Ki; Kang, Hyun-Joo; Kim, Soo Ji

    2016-01-01

    This study measured surface electromyography of the biceps brachii and triceps brachii during repeated drum playing with and without a drumstick to better understand activation of the upper arm muscles and inform the use of instrument playing for motor rehabilitation. A total of 40 healthy college students participated in this study. All participants were asked to strike a drum with their hand and with a drumstick at three different levels of stroke: soft, medium, and strong. The stroke order was randomly assigned to participants. A sound level meter was used to record the intensity of the drum playing. Surface electromyography signals were recorded at every hit during drum playing both with and without the drumstick in each of the three stroke conditions. The results demonstrated that the highest muscle activation was observed in both biceps brachii and triceps brachii with strong drum playing with and without the drumstick. A two-way repeated measures analysis of variance showed that there was a significant main effect for stroke intensity in muscle activation and produced sound level. While higher activation of the triceps brachii was observed for drum playing without a drumstick, no significant differences were found between the biceps brachii and sound level. This study demonstrated via surface electromyography data that greater muscle activation of the biceps brachii and triceps brachii does not occur with the use of drumsticks in drum playing. With the drum sound controlled, drum playing by hand can be an effective therapeutic intervention for the upper arm muscles. PMID:27419114

  13. Analysis of upper arm muscle activation using surface electromyography signals during drum playing.

    PubMed

    Chong, Hyun Ju; Kwon, Chun-Ki; Kang, Hyun-Joo; Kim, Soo Ji

    2016-06-01

    This study measured surface electromyography of the biceps brachii and triceps brachii during repeated drum playing with and without a drumstick to better understand activation of the upper arm muscles and inform the use of instrument playing for motor rehabilitation. A total of 40 healthy college students participated in this study. All participants were asked to strike a drum with their hand and with a drumstick at three different levels of stroke: soft, medium, and strong. The stroke order was randomly assigned to participants. A sound level meter was used to record the intensity of the drum playing. Surface electromyography signals were recorded at every hit during drum playing both with and without the drumstick in each of the three stroke conditions. The results demonstrated that the highest muscle activation was observed in both biceps brachii and triceps brachii with strong drum playing with and without the drumstick. A two-way repeated measures analysis of variance showed that there was a significant main effect for stroke intensity in muscle activation and produced sound level. While higher activation of the triceps brachii was observed for drum playing without a drumstick, no significant differences were found between the biceps brachii and sound level. This study demonstrated via surface electromyography data that greater muscle activation of the biceps brachii and triceps brachii does not occur with the use of drumsticks in drum playing. With the drum sound controlled, drum playing by hand can be an effective therapeutic intervention for the upper arm muscles. PMID:27419114

  14. Analysis of upper arm muscle activation using surface electromyography signals during drum playing.

    PubMed

    Chong, Hyun Ju; Kwon, Chun-Ki; Kang, Hyun-Joo; Kim, Soo Ji

    2016-06-01

    This study measured surface electromyography of the biceps brachii and triceps brachii during repeated drum playing with and without a drumstick to better understand activation of the upper arm muscles and inform the use of instrument playing for motor rehabilitation. A total of 40 healthy college students participated in this study. All participants were asked to strike a drum with their hand and with a drumstick at three different levels of stroke: soft, medium, and strong. The stroke order was randomly assigned to participants. A sound level meter was used to record the intensity of the drum playing. Surface electromyography signals were recorded at every hit during drum playing both with and without the drumstick in each of the three stroke conditions. The results demonstrated that the highest muscle activation was observed in both biceps brachii and triceps brachii with strong drum playing with and without the drumstick. A two-way repeated measures analysis of variance showed that there was a significant main effect for stroke intensity in muscle activation and produced sound level. While higher activation of the triceps brachii was observed for drum playing without a drumstick, no significant differences were found between the biceps brachii and sound level. This study demonstrated via surface electromyography data that greater muscle activation of the biceps brachii and triceps brachii does not occur with the use of drumsticks in drum playing. With the drum sound controlled, drum playing by hand can be an effective therapeutic intervention for the upper arm muscles.

  15. Open Versus Arthroscopic Biceps Tenodesis: A Comparison of Functional Outcomes

    PubMed Central

    Duchman, Kyle R; DeMik, David E.; Uribe, Bastian; Wolf, Brian R; Bollier, Matthew

    2016-01-01

    Background The proximal aspect of the long head of the biceps brachii (LHB) is a frequent source of anterior shoulder pain. Multiple techniques for LHB tenodesis have been described. However, comparative outcomes are lacking. The present study aims to compare functional results, patient reported outcomes, complications, and clinical failures for patients undergoing open versus arthroscopic LHB tenodesis. Methods All patients who underwent open or arthroscopic LHB tenodesis from 2009-2012 at a single institution were identified. Patient demographics, comorbidities, and operative variables of interest, including concomitant procedures, were recorded. Minimum 1-year follow-up was required for inclusion. Outcomes, including patient reported outcomes, physical exam findings, and complications were compared between open and arthroscopic LHB tenodesis patients. Results Overall, 45 patients (25 open, 20 arthroscopic) were available for analysis. In total, there was a single clinical failure in a patient who underwent arthroscopic LHB tenodesis. No other complications or failures were noted. Active shoulder forward elevation was increased in the open tenodesis group as compared to the arthroscopic tenodesis group (177.8 ± 9.3° vs. 171.3 ± 11.7°; p = 0.049). Otherwise, there was no difference in range of motion or strength. For both groups, both the SF-36 and ASES scores improved significantly from preoperative values. Conclusion Both open and arthroscopic LHB tenodesis provide good to excellent outcomes with few complications. Given the recent increased utilization of LHB tenodesis, future studies should use randomization and prospective data collection in order to determine if discrete patient populations are better served by either open or arthroscopic LHB tenodesis techniques PMID:27528841

  16. Endoscopic Extra-articular Surgical Removal of Heterotopic Ossification of the Rectus Femoris Tendon in a Series of Athletes

    PubMed Central

    Comba, Fernando; Piuzzi, Nicolás S.; Oñativia, José Ignacio; Zanotti, Gerardo; Buttaro, Martín; Piccaluga, Francisco

    2016-01-01

    Background: Calcific deposits in tendon, muscles, and periarticular areas are very common. Heterotopic ossification of the rectus femoris (HORF) is a rare condition, and several theories exist regarding the etiopathogenesis, which appears to be multifactorial with traumatic, genetic, and local metabolic factors involved. Although HORF typically responds to nonoperative treatment, when this approach fails, endoscopic treatment is a minimally invasive technique to address the pathology. Purpose: To report the clinical and radiological outcomes of 9 athletes with HORF who underwent endoscopic resection. Study Design: Case series; Level of evidence, 4. Methods: Nine male athletes were treated with endoscopic extra-articular resection of HORF after failure of a 6-month course of nonoperative treatment. All patients were studied with radiographs, computed tomography, and magnetic resonance imaging. Outcomes were assessed clinically using the modified Harris Hip Score (mHHS), a visual analog scale for sport activity–related pain (VAS-SRP), patient satisfaction, and ability and time to return to the preoperative sport level. Radiographic assessment was performed to determine recurrence. Results: The mean age of the patients was 32 years (range, 23-47 years). Mean follow-up was 44 months (range, 14-73 months). All patients had improved mHHS scores from a mean preoperative of 65.6 (SD, 8.2) to 93.9 (SD, 3.6). Pain decreased from a mean 8.2 preoperatively (SD, 0.9) to 0.4 (SD, 0.7) at last follow-up. There were no complications, and all patients were able to return to their previous sports at the same level except for 1 recreational athlete. There was only 1 radiological recurrence at last follow-up in an asymptomatic patient. Conclusion: To our knowledge, this is the largest case series of athletes with HORF treated with endoscopic resection. We found this extra-articular endoscopic technique to be safe and effective, showing clinical outcome improvement and 90% chance of

  17. Endoscopic Extra-articular Surgical Removal of Heterotopic Ossification of the Rectus Femoris Tendon in a Series of Athletes

    PubMed Central

    Comba, Fernando; Piuzzi, Nicolás S.; Oñativia, José Ignacio; Zanotti, Gerardo; Buttaro, Martín; Piccaluga, Francisco

    2016-01-01

    Background: Calcific deposits in tendon, muscles, and periarticular areas are very common. Heterotopic ossification of the rectus femoris (HORF) is a rare condition, and several theories exist regarding the etiopathogenesis, which appears to be multifactorial with traumatic, genetic, and local metabolic factors involved. Although HORF typically responds to nonoperative treatment, when this approach fails, endoscopic treatment is a minimally invasive technique to address the pathology. Purpose: To report the clinical and radiological outcomes of 9 athletes with HORF who underwent endoscopic resection. Study Design: Case series; Level of evidence, 4. Methods: Nine male athletes were treated with endoscopic extra-articular resection of HORF after failure of a 6-month course of nonoperative treatment. All patients were studied with radiographs, computed tomography, and magnetic resonance imaging. Outcomes were assessed clinically using the modified Harris Hip Score (mHHS), a visual analog scale for sport activity–related pain (VAS-SRP), patient satisfaction, and ability and time to return to the preoperative sport level. Radiographic assessment was performed to determine recurrence. Results: The mean age of the patients was 32 years (range, 23-47 years). Mean follow-up was 44 months (range, 14-73 months). All patients had improved mHHS scores from a mean preoperative of 65.6 (SD, 8.2) to 93.9 (SD, 3.6). Pain decreased from a mean 8.2 preoperatively (SD, 0.9) to 0.4 (SD, 0.7) at last follow-up. There were no complications, and all patients were able to return to their previous sports at the same level except for 1 recreational athlete. There was only 1 radiological recurrence at last follow-up in an asymptomatic patient. Conclusion: To our knowledge, this is the largest case series of athletes with HORF treated with endoscopic resection. We found this extra-articular endoscopic technique to be safe and effective, showing clinical outcome improvement and 90% chance of

  18. Profunda femoris artery pseudoaneurysm following revision for femoral shaft fracture nonunion

    PubMed Central

    Valli, Federico; Teli, Marco GA; Innocenti, Marco; Vercelli, Ruggero; Prestamburgo, Domenico

    2013-01-01

    Femoral artery pseudoaneurysms (FAPs) have been described following internal fixation of intertrocantheric, subtrocantheric and intracapsular femoral neck fractures as well as core decompression of the femoral head. The diagnosis of FAP is usually delayed because of non-specific clinical features like pain, haematoma, swelling, occasional fever and unexplained anaemia. Because of the insidious onset and of the possible delayed presentation of pseudoaneurysms, orthopaedic and trauma surgeons should be aware of this complication. We report a case of Profunda Femoris arterial branch pseudoaneurysm, diagnosed in a 40-year-old male 4 wk after revision with Kuntscher intramedullary nail of a femoral shaft nonunion. The diagnosis was achieved by computed tomography angiography and the lesion was effectively managed by endovascular repair. The specific literature and suggestions for treatment are discussed in the paper. PMID:23878785

  19. EMG analysis of human postural responses during parabolic flight microgravity episodes

    NASA Technical Reports Server (NTRS)

    Layne, Charles S.; Spooner, Brian S.

    1990-01-01

    Anticipatory postural activity in the trunk and legs precedes rapid shoulder flexion in unit gravity. The hypothesis that anticipatory activity is a component of a single neural command for arm movement was tested by monitoring the surface electromyographic activity of the biceps femoris, paraspinals, and deltoid muscles of three subjects during the microgravity phase of parabolic flight. If part of a single command, anticipatory postural activity would be expected to remain intact despite the absence of the body's center of gravity in a reduced gravity environment. However, in at least 75 percent of the microgravity trials anticipatory biceps femoris activity was absent, indicating a separation of postural and agonist muscle activity. Such a finding suggests that anticipatory postural biceps femoris activity may be initiated independently of agonist (deltoid) activity.

  20. Effect of vitamin D status improvement with 25-hydroxycholecalciferol on skeletal muscle growth characteristics and satellite cell activity in broiler chickens.

    PubMed

    Hutton, K C; Vaughn, M A; Litta, G; Turner, B J; Starkey, J D

    2014-08-01

    Skeletal muscle satellite cells (SC) play a critical role in the hypertrophic growth of postnatal muscle. Increases in breast meat yield have been consistently observed in broiler chickens fed 25-hydroxycholecalciferol (25OHD3), but it is unclear whether this effect is mediated by SC. Thus, our objective was to determine the effect of vitamin D status improvement by replacing the majority of dietary vitamin D3 (D3) with 25OHD3 on SC activity and muscle growth characteristics in the pectoralis major (PM) and the biceps femoris (BF) muscles. Day-old, male Ross 708 broiler chickens (n = 150) were fed 1 of 2 corn and soybean meal-based diets for 49 d. The control diet (CTL) contained 5,000 IU D3 per kg of diet and the experimental diet (25OHD3) contained 2,240 IU D3 per kg of diet + 2,760 IU 25OHD3 per kg of diet. Ten birds per treatment were harvested every 7 d. Two hours before harvest, birds were injected intraperitoneally with 5'-bromo-2'deoxyuridine (BrdU) to label mitotically active cells. Blood was collected from each bird at harvest to measure circulating concentrations of 25OHD3, a marker of vitamin D status. The PM and BF muscles were weighed and processed for cryohistological determination of skeletal muscle fiber cross-sectional area, enumeration of Myf-5+ and Pax7+ SC, and mitotically active (BrdU+) SC using immunofluorescence microscopy. Circulating 25OHD3 concentrations were greater in 25OHD3-fed birds on d 7, 14, 21, 28, 35, 42, and 49 when compared with CTL (P < 0.001). Growth performance and feed efficiency did not differ among dietary treatments (P > 0.10). Improved vitamin D status as a result of feeding 25OHD3 increased the number of mitotically active (Pax7+;BrdU+) SC (P = 0.01) and tended to increase the density of Pax7+ SC (P = 0.07) in the PM muscles of broilers on d 21 and 35, respectively. Broiler chickens fed 25OHD3 also tended to have greater Myf-5+ SC density (P = 0.09) on d 14, greater total nuclear density (P = 0.05) on d 28, and a

  1. Does the Dumbbell-Carrying Position Change the Muscle Activity in Split Squats and Walking Lunges?

    PubMed Central

    Lehnert, Michal; Zaatar, Amr M.Z.; Svoboda, Zdenek; Xaverova, Zuzana

    2015-01-01

    Abstract Stastny, P, Lehnert, M, Zaatar, AMZ, Svoboda, Z, and Xaverova, Z. Does the dumbbell-carrying position change the muscle activity in split squats and walking lunges? J Strength Cond Res 29(11): 3177–3187, 2015—The forward walking lunge (WL) and split squat (SSq) are similar exercises that have differences in the eccentric phase, and both can be performed in the ipsilateral or contralateral carrying conditions. This study aimed to determine the effects of dumbbell-carrying position on the kinematics and electromyographic (EMG) amplitudes of the gluteus medius (Gmed), vastus medialis (VM), vastus lateralis (VL), and biceps femoris during WLs and SSqs. The resistance-trained (RT) and the non–resistance-trained (NT) groups (both n = 14) performed ipsilateral WLs, contralateral WLs, ipsilateral SSqs, and contralateral SSqs in a randomized order in a simulated training session. The EMG amplitude, expressed as a percentage of the maximal voluntary isometric contraction (%MVIC), and the kinematics, expressed as the range of motion (ROM) of the hip and knee, were measured during 5 repetition maximum for both legs. The repeated measure analyses of variance showed significant differences between the RT and NT groups. The NT group showed a smaller knee flexion ROM (p < 0.001, η2 = 0.36) during both types of WLs, whereas the RT group showed a higher eccentric Gmed amplitude (p < 0.001, η2 = 0.46) during all exercises and a higher eccentric VL amplitude (p < 0.001, η2 = 0.63) during contralateral WLs. Further differences were found between contralateral and ipsilateral WLs in both the RT (p < 0.001, η2 = 0.69) and NT groups (p < 0.001, η2 = 0.80), and contralateral WLs resulted in higher eccentric Gmed amplitudes. Contralateral WLs highly activated the Gmed (90% MVIC); therefore, this exercise can increase the Gmed maximal strength. The ipsilateral loading condition did not increase the Gmed or VM activity in the RT or NT group. PMID:25968228

  2. Your Muscles

    MedlinePlus

    ... Homework? Here's Help White House Lunch Recipes Your Muscles KidsHealth > For Kids > Your Muscles Print A A ... and skeletal (say: SKEL-uh-tul) muscle. Smooth Muscles Smooth muscles — sometimes also called involuntary muscles — are ...

  3. Effect of the upper limbs muscles activity on the mechanical energy gain in pole vaulting.

    PubMed

    Frère, Julien; Göpfert, Beat; Slawinski, Jean; Tourny-chollet, Claire

    2012-04-01

    The shoulder muscles are highly solicited in pole vaulting and may afford energy gain. The objective of this study was to determine the bilateral muscle activity of the upper-limbs to explain the actions performed by the vaulter to bend the pole and store elastic energy. Seven experienced athletes performed 5-10 vaults which were recorded using two video cameras (50Hz). The mechanical energy of the centre of gravity (CG) was computed, while surface electromyographic (EMG) profiles were recorded from 5 muscles bilateral: deltoideus, infraspinatus, biceps brachii, triceps, and latissimus dorsi muscles. The level of intensity from EMG profile was retained in four sub phases between take-off (TO1) and complete pole straightening (PS). The athletes had a mean mechanical energy gain of 22% throughout the pole vault, while the intensities of deltoideus, biceps brachii, and latissimus dorsi muscles were sub phases-dependent (p<0.05). Stabilizing the glenohumeral joint (increase of deltoideus and biceps brachii activity) and applying a pole bending torque (increase of latissimus dorsi activity) required specific muscle activation. The gain in mechanical energy of the vaulter could be linked to an increase in muscle activation, especially from latissimusdorsi muscles.

  4. A CMB B-mode Search with Three Years of BICEP Observations

    NASA Astrophysics Data System (ADS)

    Bischoff, Colin; BICEP Collaboration

    2013-01-01

    The search for B-mode, or curl-type, polarization in the Cosmic Microwave Background is the most promising technique to constrain or detect primordial gravitational waves predicted by the theory of inflation. The Bicep telescope, which observed from the South Pole for three years from 2006 through 2008, is the first experiment specifically designed to target this signal. We review the observational motivations for inflation, the advantages of B-mode observations as a technique for detecting the gravitational wave background, and the design features of Bicep that optimize it for this search. The final analysis of all three seasons of Bicep data is in progress, representing a 50% increase in integration time compared to the result from Chiang et al. (2010). A preview of the three year result includes E-mode and B-mode maps, as well as the projected constraint on r, the tensor-to-scalar ratio.

  5. Can self-ordering scalar fields explain the BICEP2 B-mode signal?

    SciTech Connect

    Durrer, Ruth; Figueroa, Daniel G.; Kunz, Martin E-mail: daniel.figueroa@unige.ch

    2014-08-01

    We show that self-ordering scalar fields (SOSF), i.e. non-topological cosmic defects arising after a global phase transition, cannot explain the B-mode signal recently announced by BICEP2. We compute the full C{sub ℓ}{sup B} angular power spectrum of B-modes due to vector and tensor perturbations of SOSF, modeled in the large N limit of a spontaneously broken global O(N) symmetry. We conclude that the low ℓ multipoles detected by BICEP2 cannot be due mainly to SOSF, since they have the wrong spectrum at low multipoles. As a byproduct we derive the first cosmological constraints on this model, showing that the BICEP2 B-mode polarization data admits at most a 2-3% contribution from SOSF in the temperature anisotropies, similar to (but somewhat tighter than) the recently studied case of cosmic strings.

  6. “ROCAMBOLE-LIKE” BICEPS TENODESIS: TECHNIQUE AND RESULTS

    PubMed Central

    Godinho, Glaydson Gomes; Mesquita, Fabrício Augusto Silva; França, Flávio de Oliveira; Freitas, José Márcio Alves

    2015-01-01

    Objective: To present a new technique for bicipital tenodesis and its results: accomplished partially via arthroscopy and grounded in concepts of the normal and pathological anatomy of the tendon of the biceps long head. It is based on the predisposition of this tendon towards becoming attached to the intertubercular sulcus after rupture or tenotomy (auto-tenodesis). Methods: Evaluations were conducted on 63 patients (63 shoulders), aged from 32 to 77 years (average 55), consisting of 32 females (51%) and 31 males (49%). Thirty-five of the patients (55.6%) were over 60 years of age and 28 patients (44.4%) were under 60 years of age. Eighteen were sports participants (28.6%). Fourteen had injuries associated with the subscapularis (22.2%). The average follow up was 43 months (ranging from 12 to 74 months). The right shoulder accounted for 48 cases (76.2%), of which one was a left-handed individual and 47 were right-handed. The left shoulder accounted for 15 (23%) of the patients, of whom two were left-handed and 13 were right-handed. There were no bilateral occurrences. The statistical analysis were done using SPSS version 18. Pearson's chi-square test and continuity corrections were used to investigate the statistical significance of associations between variables. Associations were taken to be statistically significant when p was less than 0.05. Results: Residual Popeye deformity was perceived by seven patients (11.1%); it was only observed by the examiner in 15 cases (23.8%); and neither the patient nor the examiner observed it in 41 cases (65%). There were no statistically valid influences from age, participation in contact or throwing sports, subscapularis tendon-associated injury or Popeye deformity. Fifty-eight patients (92.06%) were satisfied, two patients were dissatisfied (3.17%) and three patients were indifferent (4.76%). Conclusion: The technique presented high patient satisfaction rates (92.06%) and residual deformity was perceived by 11.1% of the

  7. Biceps Tenotomy Versus Tenodesis in Active Patients Younger Than 55 Years

    PubMed Central

    Friedman, Jamie L.; FitzPatrick, Jennifer L.; Rylander, Lucas S.; Bennett, Christine; Vidal, Armando F.; McCarty, Eric C.

    2015-01-01

    Background: Proximal biceps pathology is a significant factor in shoulder pain. Surgical treatment options include biceps tenotomy and subpectoral biceps tenodesis. Tenotomy is a simple procedure, but it may produce visible deformity, subjective cramping, or loss of supination strength. Tenodesis is a comparatively technical procedure involving a longer recovery, but it has been hypothesized to achieve better outcomes in younger active patients (<55 years). Hypothesis: This study investigated the outcomes of younger patients who underwent either a biceps tenotomy or tenodesis as part of treatment for shoulder pain. The hypothesis was that, apart from cosmetic deformity, there will be no difference in outcome between the 2 treatment options. Study Design: Cohort study; Level of evidence, 3. Methods: Isometric strength and endurance testing of operative and nonoperative shoulders for forearm supination (FS) and elbow flexion (EF) were tested utilizing an isometric dynamometer. Objective physical assessment was also performed. Subjective outcomes using the modified American Shoulder and Elbow Surgeons score (ASES); Disability of the Arm, Shoulder, and Hand (DASH); visual analog scale (VAS); and perceived biceps symptoms were collected. Results: A total of 42 patients (22 tenotomy, 20 tenodesis) with an average follow-up of 3.3 years were studied. The average age at follow-up was 49.9 years. Thirty-five percent (7/20) of tenotomy patients exhibited a “Popeye” deformity, compared with 18.2% (4/22) of tenodesis patients. Strength prior to fatiguing exercise was similar between tenodesis and tenotomy for FS (6.9 vs 7.3 lbs; P < .05), EF in neutral (35.4 vs 35.4 lbs), and EF in supination (33.8 vs 34.2 lbs). Strength was not significantly different between groups for isometric strength and endurance measures. Subjective functional outcome measured by the DASH, ASES, and VAS scores were similar between groups. Frequency of complaints of cramping was higher in the

  8. Agonist and Antagonist Muscle EMG Activity Pattern Changes with Skill Acquisition.

    ERIC Educational Resources Information Center

    Engelhorn, Richard

    1983-01-01

    Using electromyography (EMG), researchers studied changes in the control of biceps and triceps brachii muscles that occurred as women college students learned two elbow flexion tasks. Data on EMG activity, angular kinematics, training, and angular displacement were analyzed. (Author/PP)

  9. Signaling Pathways Related to Protein Synthesis and Amino Acid Concentration in Pig Skeletal Muscles Depend on the Dietary Protein Level, Genotype and Developmental Stages

    PubMed Central

    Liu, Yingying; Li, Fengna; Kong, Xiangfeng; Tan, Bie; Li, Yinghui; Duan, Yehui; Blachier, François; Hu, Chien-An A.; Yin, Yulong

    2015-01-01

    Muscle growth is regulated by the homeostatic balance of the biosynthesis and degradation of muscle proteins. To elucidate the molecular interactions among diet, pig genotype, and physiological stage, we examined the effect of dietary protein concentration, pig genotype, and physiological stages on amino acid (AA) pools, protein deposition, and related signaling pathways in different types of skeletal muscles. The study used 48 Landrace pigs and 48 pure-bred Bama mini-pigs assigned to each of 2 dietary treatments: lower/GB (Chinese conventional diet)- or higher/NRC (National Research Council)-protein diet. Diets were fed from 5 weeks of age to respective market weights of each genotype. Samples of biceps femoris muscle (BFM, type I) and longissimus dorsi muscle (LDM, type II) were collected at nursery, growing, and finishing phases according to the physiological stage of each genotype, to determine the AA concentrations, mRNA levels for growth-related genes in muscles, and protein abundances of mechanistic target of rapamycin (mTOR) signaling pathway. Our data showed that the concentrations of most AAs in LDM and BFM of pigs increased (P<0.05) gradually with increasing age. Bama mini-pigs had generally higher (P<0.05) muscle concentrations of flavor-related AA, including Met, Phe, Tyr, Pro, and Ser, compared with Landrace pigs. The mRNA levels for myogenic determining factor, myogenin, myocyte-specific enhancer binding factor 2 A, and myostatin of Bama mini-pigs were higher (P<0.05) than those of Landrace pigs, while total and phosph