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

Purpose: Passive muscle tension is increased after 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. The authors measured hamstring passive tension throughout a 90-min simulated soccer match (SAFT⁹⁰), including the warm-up period and every 15 min throughout the 90-min simulation. Methods: Passive hamstring tension of 15 amateur male soccer players was measured using the instrumented straight-leg-raise test. Absolute torque (Nm) and slope (Nm/°) of the recorded torque-angular position curve were used for data analysis, in addition to total leg range of motion (ROM). Players performed a 15-min prematch warm-up, then performed the SAFT⁹⁰ including a 15-min halftime rest period. Results: Reductions in passive stiffness of 20-50° of passive hip flexion of 22.1-29.2% (P <.05) were observed after the warm-up period. During the SAFT⁹⁰, passive tension increased in the latter 20% of the range of motion of 10.1-10.9% (P <.05) concomitant to a 4.5% increase in total hamstring ROM (P =.0009). Conclusions: The findings of this study imply that hamstring passive tension is reduced after 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 ROM and passive tension increases are best explained by improved stretch tolerance.