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The functional significance of hamstrings composition: is it really a “fast” muscle group?
Author(s) -
Evangelidis Pavlos E.,
Massey Garry J.,
Ferguson Richard A.,
Wheeler Patrick C.,
Pain Matthew T.G.,
Folland Jonathan P.
Publication year - 2017
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12786
Subject(s) - isometric exercise , biceps , explosive strength , myosin , eccentric , anatomy , strain (injury) , concentric , contraction (grammar) , medicine , muscle contraction , chemistry , physical medicine and rehabilitation , mathematics , physics , biochemistry , geometry , quantum mechanics
Hamstrings muscle fiber composition may be predominantly fast‐twitch and could explain the high incidence of hamstrings strain injuries. However, hamstrings muscle composition in vivo , and its influence on knee flexor muscle function, remains unknown. We investigated biceps femoris long head ( BF lh) myosin heavy chain ( MHC ) composition from biopsy samples, and the association of hamstrings composition and hamstrings muscle volume (using MRI ) with knee flexor maximal and explosive strength. Thirty‐one young men performed maximal (concentric, eccentric, isometric) and explosive (isometric) contractions. BF lh exhibited a balanced MHC distribution [mean ± SD (min‐max); 47.1 ± 9.1% (32.6–71.0%) MHC ‐I, 35.5 ± 8.5% (21.5–60.0%) MHC ‐ IIA , 17.4 ± 9.1% (0.0–30.9%) MHC ‐ IIX ]. Muscle volume was correlated with knee flexor maximal strength at all velocities and contraction modes ( r = 0.62–0.76, P < 0.01), but only associated with late phase explosive strength (time to 90 Nm; r = −0.53, P < 0.05). In contrast, BF lh muscle composition was not related to any maximal or explosive strength measure. BF lh MHC composition was not found to be “fast”, and therefore composition does not appear to explain the high incidence of hamstrings strain injury. Hamstrings muscle volume explained 38–58% of the inter‐individual differences in knee flexor maximum strength at a range of velocities and contraction modes, while BF lh muscle composition was not associated with maximal or explosive strength.