Different visual stimuli affect muscle activation at the knee during sidestepping.Journal of Sports Sciences
Volume 37, 2019 - Issue 10, Pages 1123-1128
Marcus J.C. Leea,b, David G. Lloyda,c, Brendan S. Laya, Paul D. Bourkea Jacqueline A. Aldersona,d.
aSchool of Sport Science, Exercise & Health, The University of Western Australia, Crawley, Western Australia, Australia
Increasing knee stability via appropriate muscle activation could reduce anterior cruciate ligament (ACL) injury risk during unplanned sidestepping. High-level athletes may activate their knee muscles differently from low-level athletes when responding to quasi-game realistic versus non game-realistic stimuli. Eleven high-level and 10 low-level soccer players responded to a non game-realistic arrow-planned condition (AP), a quasi game-realistic one-defender scenario (1DS) and two-defender scenario (2DS), and an arrow-unplanned condition (AUNP), that imposed increasing time constraints to sidestep. Activation from eight knee muscles during sidestepping was measured during pre-contact and weight-acceptance. Knee flexor-extensor co-activation ratios were established. Muscle activation levels increased by approximately 27% solely in the 1DS in both sidestepping phases. In the 2DS, the shift from a flexor dominant co-activation strategy in pre-contact toward extensor dominance in weight-acceptance commenced earlier for the high-level players. Quasi game-realistic information allowed for anticipatory increases in knee muscle activation regardless of expertise levels but only when the time demands to respond were low (1DS). High-level players were better at interpreting complex game- realistic information (2DS) to activate their knee extensors earlier in preparation for single-leg landing during weight-acceptance.Keywords
Sidestep; cutting; EMG; ACL; injury; biomechanics