scholarly journals Effects of knee flexor submaximal isometric contraction until exhaustion on semitendinosus and biceps femoris long head shear modulus in healthy individuals

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bruno Mendes ◽  
Telmo Firmino ◽  
Raúl Oliveira ◽  
Tiago Neto ◽  
Carlos Cruz-Montecinos ◽  
...  
Keyword(s):  
Isometric Contraction ◽  
Shear Wave Elastography ◽  
Biceps Femoris ◽  
Time To Exhaustion ◽  
Healthy Individuals ◽  
Maximal Voluntary Isometric Contraction ◽  
Knee Flexor ◽  
Task Time ◽  
Long Head ◽  
Biceps Femoris Long Head

Abstract This study examined whether a knee flexor isometric contraction at 20% of maximal voluntary isometric contraction until exhaustion would alter the biceps femoris long head (BFlh) and semitendinosus (ST) active stiffness, assessed using ultrasound-based shear wave elastography. Twelve healthy individuals participated in 2 sessions separated by 7 days. Time to exhaustion was similar in both sessions (day 1: 443.8 ± 192.5 s; day 2: 474.6 ± 131.7 s; p = 0.323). At the start of the fatigue task, the ST showed greater active stiffness than the BFlh (p < 0.001), with no differences between days (p = 0.08). The ST active stiffness then decreased from 40% of the task time to exhaustion (− 2.2 to − 13.3%, p = 0.027) until the end of the task (− 16.1 to − 22.9%, p = 0.012), while no significant changes were noted in the BFlh (p = 0.771). Immediately after the fatigue task, a decrease in active stiffness was observed in the ST (− 11.8 to − 17.8%, p < 0.001), but not in the BFlh (p = 0.551). Results were consistent between the 2 testing sessions (p = 0.07–0.959). The present results indicate that fatigue alters the hamstring active stiffness pattern.

scholarly journals Biceps Femoris Activation during Hamstring Strength Exercises: A Systematic Review

2021 ◽  
Vol 18 (16) ◽  
pp. 8733
Author(s):  
Luis Llurda-Almuzara ◽  
Noé Labata-Lezaun ◽  
Carlos López-de-Celis ◽  
Ramón Aiguadé-Aiguadé ◽  
Sergi Romaní-Sánchez ◽  
...  
Keyword(s):  
Systematic Review ◽  
Isometric Contraction ◽  
Biceps Femoris ◽  
Cochrane Library ◽  
Exclusion Criteria ◽  
Maximal Voluntary Isometric Contraction ◽  
Cross Sectional ◽  
Strength Exercises ◽  
Long Head ◽  
Biceps Femoris Long Head

Background: The aim of the study was to systematically evaluate the biceps femoris long head activation across cross-sectional hamstring strength exercise studies. Methods: A systematic review design was followed. The search strategy conducted in PubMed, Cochrane Library, and Web of Sciences databases found a total of 3643 studies. Once inclusion and exclusion criteria were applied, 29 studies were finally included in this systematic review. A total of 507 participants and 114 different exercises were analyzed. Exercises were evaluated individually and grouped into several categories: Nordics, isokinetic exercises, lunges, squats, deadlifts, good mornings, hip thrusts, bridges, leg curls, swings, hip and back extensions, and others. Results: Results showed the isokinetic and Nordic exercises as the categories with highest biceps femoris activation (>60% of Maximal Voluntary Isometric Contraction). Nordic hamstring exercise ankle dorsiflexion was the exercise that achieved the highest biceps femoris long head activation (128.1% of its Maximal Voluntary Isometric Contraction). Conclusions: The results from this systematic review suggest that isokinetic and Nordic exercises seem to be the best option to activate biceps femoris long head. Future studies evaluating the implementation of these exercises in prevention programs are needed.

Poststretch Isometric Contractions of the Hamstrings: Just a Brief Stretch to Achieve Supramaximal Isometric Force

2021 ◽  
pp. 1-7
Author(s):  
Neil Chapman ◽  
John William Whitting ◽  
Suzanne Broadbent ◽  
Zachary Crowley-McHattan ◽  
Rudi Meir
Keyword(s):  
Isometric Contraction ◽  
Knee Flexion ◽  
Isometric Force ◽  
Biceps Femoris ◽  
Isometric Contractions ◽  
Maximal Voluntary Isometric Contraction ◽  
Hamstring Strain ◽  
Long Head ◽  
Biceps Femoris Long Head ◽  
Knee Flexors

Hamstring strain injuries are common in sport. Supramaximal eccentric or high-intensity isometric contractions are favored in hamstring strain injury prevention. The effect of combining these contraction modes in such prevention programs as a poststretch isometric contraction is unknown. Poststretch isometric contractions incorporate an active stretch and result in greater final isometric force than isometric contractions at comparable joint angles. This study compared torque and muscle activation levels between maximal voluntary isometric contraction and maximal poststretch isometric contractions of the knee flexors. Participants (n = 9) completed baseline maximal voluntary isometric contraction at 150° knee flexion and maximal poststretch isometric contractions at 120° knee flexion actively stretching at 60°/s to 150° knee flexion for final isometric contraction. Torque of the knee flexors and surface electromyography root mean square (sEMGRMS) of biceps femoris long head were simultaneously recorded and compared between baseline and poststretch isometric at 150° knee flexion. Torque was 14% greater in the poststretch isometric condition compared with baseline maximal voluntary isometric contraction (42.45 [20.75] N·m, 14% [22.18%], P < .001) without increase in sEMGRMS of biceps femoris long head (−.03 mV, ±.06, P = .130, d = .93). Poststretch isometric contractions resulted in supramaximal levels of poststretch isometric torque without increased activation of biceps femoris long head.

Hamstring Eccentric Strengthening Program: Does Training Volume Matter?

2020 ◽  
Vol 15 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Mathieu Lacome ◽  
Simon Avrillon ◽  
Yannick Cholley ◽  
Ben M. Simpson ◽  
Gael Guilhem ◽  
...  
Keyword(s):  
Biceps Femoris ◽  
High Volume ◽  
Soccer Players ◽  
Eccentric Training ◽  
Fascicle Length ◽  
Knee Flexor ◽  
Low Volume ◽  
Long Head ◽  
Biceps Femoris Long Head ◽  
Flexor Strength

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.

Is Biceps Femoris Aponeurosis Size an Independent Risk Factor for Strain Injury?

2020 ◽  
Vol 41 (08) ◽  
pp. 552-557 ◽  
Author(s):  
Sandro R. Freitas ◽  
Filipe Abrantes ◽  
Francisco Santos ◽  
Vasco Mascarenhas ◽  
Raúl Oliveira ◽  
...  
Keyword(s):  
Risk Factor ◽  
Independent Risk Factor ◽  
Biceps Femoris ◽  
Isometric Strength ◽  
Resonance Imaging ◽  
Injured Limb ◽  
Previous Injury ◽  
Knee Flexor ◽  
Long Head ◽  
Biceps Femoris Long Head

AbstractThis study examined whether professional footballers with previous biceps femoris long head (BFLH) injury in the last 3-years present a smaller proximal aponeurosis (Apo-BFLH) size compared to footballers with no previous injury. We examined the Apo-BFLH and BFLH size using magnetic resonance imaging and tested the knee flexor maximal isometric strength in 80 thighs of 40 footballers. Apo-BFLH size parameters were processed using a semi-automated procedure. Outcomes were compared between thighs with (n=9) vs. without (n=71) previous BFLH injury. No differences were observed between injured and non-injured thighs for the Apo-BFLH and BFLH size parameters (p>0.05) except for Apo-BFLH volume, which was higher in the non-injured thighs of athletes with previous injury (3692.1±2638.4 mm3, p<0.006) compared to the left (2274.1±798.7 mm3) thighs of athletes without previous injury. A higher knee flexor isometric strength was observed in the injured limb of athletes with previous BFLH injury (196.5±31.9 Nm, p<0.003) compared to the left (156.2±31.4 Nm) and right (160.0±31.4 Nm) thighs of non-injured athletes. The present results suggest that BFLH proximal aponeurosis size should not be considered as an independent risk factor for strain injury.

Influence of submaximal isometric contractions of the hamstrings on electromyography activity and force while functioning as hip extensors

2020 ◽  
pp. 1-8
Author(s):  
Dasom Oh ◽  
Wootaek Lim
Keyword(s):  
Prone Position ◽  
Supine Position ◽  
Isometric Contraction ◽  
Muscle Length ◽  
Biceps Femoris ◽  
Emg Activity ◽  
Isometric Contractions ◽  
Significant Difference ◽  
Extension Force ◽  
Long Head

BACKGROUND: Although the medial and lateral hamstrings are clearly distinct anatomically and have different functions in the transverse plane, they are often considered as one muscle during rehabilitation. OBJECTIVE: The purpose of the study was to compare the electromyographic (EMG) activity between the prone position and the supine position during maximal isometric contraction and to additionally confirm the effect of submaximal isometric contractions on EMG activity of medial and lateral hamstrings, and force. METHODS: In the prone position, EMG activities of the long head of biceps femoris (BFLH) and semitendinosus (ST) were measured during the maximal isometric contraction. In the supine position, hip extension force with EMG activity were measured during the maximal and the submaximal isometric contractions. RESULTS: EMG activity in the prone position was significantly decreased in the supine position. In the supine position, there was a significant difference between the BFLH and ST during the maximal isometric contraction, but not during the submaximal isometric contractions. CONCLUSIONS: The dependence on the hamstrings could be relatively lower during hip extensions. When the medial and lateral hamstrings are considered separately, the lateral hamstrings may show a more active response, with increased muscle length, in clinical practice.

scholarly journals Poor agreement between ultrasound and inbuilt diffusion tensor MRI measures of biceps femoris long head fascicle length

2018 ◽  
Vol 2 (2) ◽  
pp. 58-63 ◽  
Author(s):  
Fearghal P. Behan ◽  
Robin Vermeulen ◽  
Tessa Smith ◽  
Javier Arnaiz ◽  
Rodney Whiteley ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Biceps Femoris ◽  
Diffusion Tensor Mri ◽  
Poor Agreement ◽  
Fascicle Length ◽  
Long Head ◽  
Biceps Femoris Long Head

Muscle- and Region-Specific Associations Between Muscle Size and Muscular Strength During Hip Extension and Knee Flexion in the Hamstrings

2021 ◽  
pp. 1-6
Author(s):  
Raki Kawama ◽  
Masamichi Okudaira ◽  
Hirohiko Maemura ◽  
Satoru Tanigawa
Keyword(s):  
Knee Flexion ◽  
Muscular Strength ◽  
Sports Injuries ◽  
Biceps Femoris ◽  
Muscle Size ◽  
Cross Sectional ◽  
Long Head ◽  
Hip Extension ◽  
Flexion Strength ◽  
Biceps Femoris Long Head

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.

Biceps femoris long head muscle fascicle length does not differ between sexes

2019 ◽  
Vol 37 (21) ◽  
pp. 2452-2458
Author(s):  
Fearghal P. Behan ◽  
Rachael Moody ◽  
Tejal Sarika Patel ◽  
Edward Lattimore ◽  
Thomas M. Maden-Wilkinson ◽  
...  
Keyword(s):  
Biceps Femoris ◽  
Fascicle Length ◽  
Muscle Fascicle ◽  
Long Head ◽  
Biceps Femoris Long Head

scholarly journals MR biomarkers predict clinical function in Duchenne muscular dystrophy

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 ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Lower Extremity ◽  
Vastus Lateralis ◽  
Strong Relationship ◽  
Biceps Femoris ◽  
Loss Of Function ◽  
Long Head ◽  
Biceps Femoris Long Head ◽  
Over Time

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.

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