scholarly journals Influences of Change in Muscle Thickness on the Muscle Fiber Contraction Dynamics of Biceps Femoris Long Head During High-Speed Running

2021 ◽  
Vol 45 (3) ◽  
pp. 179-187
Author(s):  
Terumitsu MIYAZAKI ◽  
Norihisa FUJII
Author(s):  
Kevin Cronin ◽  
Eamonn Delahunt ◽  
Shane Foley ◽  
Giuseppe De Vito ◽  
Conor McCarthy ◽  
...  

AbstractHamstring strains are the most prevalent injury sustained by field-sport athletes. Insufficiencies in the architectural characteristics of the hamstring muscles can heighten an athlete’s risk of incurring a hamstring strain. To evaluate the influence of hamstring muscle architectural characteristics (i. e., fascicle length, pennation angle, muscle thickness) on injury risk, it is necessary to precisely evaluate these characteristics. Considering this, our aim was to develop and evaluate the precision of a novel semi-automated tracing software to measure the architectural characteristics of the biceps femoris long head (the most commonly injured hamstring muscle) in B-mode ultrasound images. We acquired static sonograms of the biceps femoris long head from ten healthy male field-sport athletes. The architectural characteristics (fascicle length, pennation angle, and muscle thickness) of participants’ biceps femoris long head were evaluated 10 times using the tracing software, with the specific purpose of determining its measurement precision. The tracing software precisely measured the architectural characteristics of the participants’ biceps femoris long head: fascicle length (% CV: 0.64–1.12), pennation angle (% CV: 2.58–10.70), muscle thickness (% CV: 0.48–2.04) Our semi-automated skeletal muscle tracing algorithm precisely measures fascicle length, pennation angles, and muscle thickness of the biceps femoris long head in static B-mode ultrasound images.


2018 ◽  
Vol 2 (2) ◽  
pp. 58-63 ◽  
Author(s):  
Fearghal P. Behan ◽  
Robin Vermeulen ◽  
Tessa Smith ◽  
Javier Arnaiz ◽  
Rodney Whiteley ◽  
...  

2021 ◽  
pp. 1-6
Author(s):  
Toshiaki Soga ◽  
Taspol Keerasomboon ◽  
Kei Akiyama ◽  
Norikazu Hirose

Context: This study aimed to examine the differences in electromyographic (EMG) activity of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles, break-point angle (BPA), and the angle at peak BFlh EMG activity between bilateral and unilateral Nordic hamstring exercise (NHE) on a sloped platform. Design: This study was designed as a case-control study. Methods: Fourteen men participated in the study. The participants initially performed maximum voluntary isometric contraction (MVIC) on the prone leg curl to normalize the peak hamstring EMG amplitude as the %MVIC. Then, participants were randomized to perform the following 3 variations of NHE: bilateral (N40) or unilateral (N40U) NHE with a platform angle of 40°, and unilateral NHE with a platform angle of 50° (N50U). The EMG activities of the BFlh and ST and the knee flexion angle during the NHE variations were recorded to calculate the EMG activity of the BFlh and ST in terms of the %MVIC, the angle at peak BFlh EMG, and BPA. Results: The BFlh %MVIC was significantly higher in N40U (P < .05) and N50U (P < .05) than in N40. A significant difference in BFlh %MVIC and ST %MVIC was observed between N40U (P < .05) and N50U (P < .05). The mean values of BPA and the angle at peak BFlh EMG were <30° for all NHE variations. Conclusions: In the late swing phase of high-speed running, BFlh showed higher EMG activity; thus, unilateral NHE may be a specific hamstring exercise for hamstring injury prevention.


2021 ◽  
pp. 1-6
Author(s):  
Raki Kawama ◽  
Masamichi Okudaira ◽  
Hirohiko Maemura ◽  
Satoru Tanigawa

Context: Strength deficits of the hamstrings following sports injuries decrease athletic performance and increase the risk of injury recurrence. Previous studies have shown a high correlation between the muscular strength during hip-extension and knee-flexion and total muscle size of the hamstrings. However, it remains unclear which region of the individual hamstring muscles is closely associated with muscular strength. Objective: To investigate the relationship between the size of each region of the individual hamstring muscles and muscular strength during hip extension and knee flexion. Design: Within-subject repeated measures. Setting: University laboratory. Participants: Twenty healthy young male volunteers who regularly engaged in sports activities. Outcome Measures: Anatomical cross-sectional areas were acquired from the proximal, middle, and distal regions of the biceps femoris long head, biceps femoris short head, semitendinosus, and semimembranosus. Hip-extension and knee-flexion strength were measured during maximal voluntary isometric and concentric contractions (angular velocities of 60°/s and 180°/s). Results: The anatomical cross-sectional area of the distal regions in biceps femoris long head (r = .525–.642) and semitendinosus (r = .567) were significantly correlated with hip-extension strength under all conditions and only at an angular velocity of 180°/s, respectively. Meanwhile, anatomical cross-sectional areas of the distal regions in biceps femoris short head (r = .587–.684) and semimembranosus (r = .569–.576) were closely associated with knee-flexion strength under all conditions. Conclusion: These results suggest that muscle size in the distal regions of biceps femoris long head and semitendinosus greatly contributes to the production of hip-extension strength, whereas that of biceps femoris short head and semimembranosus significantly contributes to the generation of knee-flexion strength. These findings could be useful for designing training and rehabilitation programs to efficiently improve strength deficits following sports injuries such as strain injury and anterior cruciate ligament tears.


2019 ◽  
Vol 37 (21) ◽  
pp. 2452-2458
Author(s):  
Fearghal P. Behan ◽  
Rachael Moody ◽  
Tejal Sarika Patel ◽  
Edward Lattimore ◽  
Thomas M. Maden-Wilkinson ◽  
...  

Neurology ◽  
2020 ◽  
Vol 94 (9) ◽  
pp. e897-e909 ◽  
Author(s):  
Alison M. Barnard ◽  
Rebecca J. Willcocks ◽  
William T. Triplett ◽  
Sean C. Forbes ◽  
Michael J. Daniels ◽  
...  

ObjectiveTo investigate the potential of lower extremity magnetic resonance (MR) biomarkers to serve as endpoints in clinical trials of therapeutics for Duchenne muscular dystrophy (DMD) by characterizing the longitudinal progression of MR biomarkers over 48 months and assessing their relationship to changes in ambulatory clinical function.MethodsOne hundred sixty participants with DMD were enrolled in this longitudinal, natural history study and underwent MR data acquisition of the lower extremity muscles to determine muscle fat fraction (FF) and MRI T2 biomarkers of disease progression. In addition, 4 tests of ambulatory function were performed. Participants returned for follow-up data collection at 12, 24, 36, and 48 months.ResultsLongitudinal analysis of the MR biomarkers revealed that vastus lateralis FF, vastus lateralis MRI T2, and biceps femoris long head MRI T2 biomarkers were the fastest progressing biomarkers over time in this primarily ambulatory cohort. Biomarker values tended to demonstrate a nonlinear, sigmoidal trajectory over time. The lower extremity biomarkers predicted functional performance 12 and 24 months later, and the magnitude of change in an MR biomarker over time was related to the magnitude of change in function. Vastus lateralis FF, soleus FF, vastus lateralis MRI T2, and biceps femoris long head MRI T2 were the strongest predictors of future loss of function, including loss of ambulation.ConclusionsThis study supports the strong relationship between lower extremity MR biomarkers and measures of clinical function, as well as the ability of MR biomarkers, particularly those from proximal muscles, to predict future ambulatory function and important clinical milestones.ClinicalTrials.gov identifierNCT01484678.


2020 ◽  
Vol 15 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Mathieu Lacome ◽  
Simon Avrillon ◽  
Yannick Cholley ◽  
Ben M. Simpson ◽  
Gael Guilhem ◽  
...  

Aim: To compare the effect of low versus high volume of eccentric-biased hamstring training programs on knee-flexor strength and fascicle length changes in elite soccer players. Methods: A total of 19 elite youth soccer players took part in this study and were randomly assigned into 2 subgroups. For 6 weeks in-season, the groups performed either a low-volume (1 set per exercise; 10 repetitions in total) or a high-volume (4 sets; 40 repetitions) eccentric training of their knee flexors. After 6-weeks midtraining (MID), players performed the alternate training regimen. Each training set consisted of 4 repetitions of the Nordic hamstring exercise and 6 repetitions of the bilateral stiff-leg deadlift. Eccentric knee-flexor strength (NordBord) as well as biceps femoris long head and semimembranosus fascicle length (scanned with ultrasound scanner) were assessed during pretraining (PRE), MID, and posttraining (POST) tests. Results: Knee-flexor eccentric strength very likely increased from PRE to MID (low volume: +11.3% [7.8%] and high volume: 11.4% [5.3%]), with a possibly-to-likely increase in biceps femoris long head (+4.5% [5.0%] and 4.8% [2.5%]) and semimembranosus (+4.3% [4.7%] and 6.3% [6.3%]) fascicle length in both groups. There was no substantial changes between MID and POST. Overall, there was no clear between-group difference in the changes from PRE to MID and MID to POST for neither knee-flexor eccentric strength, biceps femoris long head, nor semimembranosus fascicle length. Conclusions: Low-volume knee-flexor eccentric training is as effective as a greater training dose to substantially improve knee-flexor strength and fascicle length in-season in young elite soccer players. Low volume is, however, likely more appropriate to be used in an elite team facing congested schedules.


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