Angle-Specific Changes in Eccentric Hamstring Torque and Hamstring to Quad Ratio Following Simulated Soccer

Abstract

Background Soccer-specific fatigue decreases eccentric peak torque and the functional peak hamstring to quadriceps torque ratio (fH ecc :Q con ), changes thought to increase the risk of hamstring strain (HS). Inadequate eccentric muscle strength specifically at long length may also be a risk factor for HS. The effect of simulated soccer on the hamstring eccentric torque-angle profile, or the hamstring:quad torque ratio at specific joint angles has not been reported. Objective To determine the effect of a simulated soccer on angle-specific eccentric hamstring torque and angle-specific. H ecc :Q con (AS.H ecc :Q con ) across the range of motion. Design Acute intervention. Setting Semi-professional soccer. Participants 9 male players. Risk factor assessment Isokinetic concentric and eccentric knee flexion and concentric knee extension was evaluated in the dominant limb at 120°·s −1 pre and post the Loughborough Intermittent Shuttle Test (LIST). Main outcome measurements Changes in eccentric hamstrings torque, concentric quadriceps torque and hamstring:quadriceps torque ratios at 9 joint angles (AS.H ecc :Q con ), angle of peak torque (APT), and fH ecc :Q con . Results The LIST resulted in significant decreases in eccentric hamstring torque at 60˚, 50˚and 10˚and a significant (21.8%) decrease in AS.H ecc :Q con at 10˚(P<.05). Eccentric hamstring APT increased significantly (P<.05) from 7.1˚to 18.8˚. Conclusions Simulated soccer produces angle-specific changes in hamstring eccentric torque and in AS.H ecc :Q con and a shift in the eccentric hamstring APT. Our findings suggest that a prevention programs should both increase fatigue resistance in the hamstrings and include exercises that specifically develop longlength eccentric hamstring strength. Further research is also needed to determine if the evaluation of angle-specific.H ecc : Q con improves the predictive power of injury risk screening over assessment of the peak torque fH ecc :Q con alone.