Abstract
BackgroundThis study examined whether passive hamstring tissue stiffness and/or stretch tolerance explain the relationship between sex and hamstring extensibility.MethodsNinety healthy participants, 45 men and 45 women (mean ± SD; age 24.6 ± 5.9 years, height 1.72 ± 0.09 m, weight 74.6 ± 14.1 kg) volunteered for this study. The instrumented straight leg raise was used to determine hamstring extensibility and allow measurement of stiffness and stretch tolerance (visual analog pain score, VAS).ResultsHamstring extensibility was 9.9° greater in women compared to men (p = 0.003). VAS scores were 16 mm lower in women (p = 0.001). Maximal stiffness (maximal applied torque) was not different between men and women (p = 0.42). Passive stiffness (slope from 20-50° hip flexion) was 0.09 Nm.°-1 lower in women (p = 0.025). For women, linear and stepwise regression showed that no predictor variables were associated with hamstring extensibility (adjusted r2 = -0.03, p = 0.61). For men, 44% of the variance in hamstring extensibility was explained by VAS and maximal applied torque (adjusted r2 = 0.44, p < 0.001), with 41% of the model accounted for by the relationship between higher VAS scores and lower extensibility (standardized β coefficient = -0.64, p < 0.001).ConclusionsThe results of this study suggest that stretch tolerance and not passive stiffness explains hamstring extensibility, but this relationship is only manifest in men.
Highlights
This study examined whether passive hamstring tissue stiffness and/or stretch tolerance explain the relationship between sex and hamstring extensibility
Main findings The main findings of this study were 1) women had lower passive stiffness through a common range of motion, better stretch tolerance, and greater hamstring extensibility compared to men, and 2) stretch tolerance, but not passive stiffness, was a significant predictor of total hamstring extensibility for men only
One study reported that increased electromechanical delay (EMD) of the medial hamstrings during the instrumented passive straight leg raise (iSLR) test was associated with greater hamstring extensiblity in women, suggesting that the neuromuscular control of the hamstrings during stretch is altered in women [5]
Summary
This study examined whether passive hamstring tissue stiffness and/or stretch tolerance explain the relationship between sex and hamstring extensibility. Often measured during an instrumented passive straight leg raise (iSLR) test to allow observation of torque applied during stretch [11,14,15], some research that has concluded passive stiffness does not explain extensibility, either acutely or following training [8,10,11,16]. These studies typically define passive stiffness from the maximal torque measured at the end of the hamstrings range of motion [8,10,11,16]. The reliance on measurement of maximal torque rather than examining changes in torque during the range of motion has contributed to the conclusion that hamstring extensibility is probably best explained by stretch tolerance
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
