Changes in passive tension of the hamstring muscles during a simulated soccer match

Passive muscle tension is increased following damaging eccentric exercise. Hamstring strain injury is associated with damaging eccentric muscle actions, but no research has examined changes in hamstring passive muscle tension throughout a simulated sport activity. We measured hamstring passive tension throughout a 90-minute simulated soccer match, including the warm-up period, and every 15-minutes throughout the 90-minute simulation.Passive hamstring tension of fifteen amateur male soccer players was measured using the instrumented straight leg raise test. Absolute torque (Nm) and slope (Nm.°-1) of the recorded torque-angular position curve were used for data analysis, in addition to total leg range of motion. Players performed a 15-minute pre-match warm-up, then performed the 90-minute soccer simulation (SAFT90) including a 15-minute half-time rest period.Reductions in passive stiffness from 20 to 50° of passive hip flexion between 22.1 to 29.2% (p<0.05) were observed after the warm-up period. During the SAFT90 passive tension increased in the latter 20% of the range of motion between 10.1 to 10.9% (p<0.05) concomitant to a 4.5% increase in total hamstring range of motion (p=0.0009).The findings of this study imply that hamstring passive tension is reduced following an active warm-up that includes dynamic stretching, but does not increase in a pattern suggestive of eccentric induced muscle damage during soccer-specific intermittent exercise. Hamstring range of motion and passive tension increases are best explained by improved stretch tolerance.