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Reduced biceps femoris myoelectrical activity influences eccentric knee flexor weakness after repeat sprint running
Author(s) -
Timmins R. G.,
Opar D. A.,
Williams M. D.,
Schache A. G.,
Dear N. M.,
Shield A. J.
Publication year - 2014
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.12171
Subject(s) - sprint , biceps , eccentric , medicine , flexor muscles , physical medicine and rehabilitation , eccentric exercise , knee flexion , physical therapy , anatomy , muscle damage , physics , quantum mechanics
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 ( MH s) 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.