Passive compliance and length of the hamstring muscles of healthy men anc women.

This study examined the passive compliance and length of the hamstring muscles of 15 healthy men and 15 healthy women (ages 21-37) with passive straight-leg-raising between 65° and 80°. Subjects were positioned on their left sides with the pelvis stabilized and the right thigh fixed at 90° on a horizontal platform. After three practice trials of maximal passive knee extension, subjects received three trials for data collection. Muscle activity was monitored with surface EMG and passive resistance to knee extension was measured with a dynamometer as the limb was photographed at six force-dependent positions. The passive compliance was computed as the ratio of the change in the knee angle (ΔAngle) to the change in passive torque (ΔTorque), (ΔAngle/ΔTorque). Hamstring muscle lengths were measured simultaneously. An ANovA revealed a difference (P = 0·001) between the passive compliance ratios of the men (1·4 ± 0·-03) and women (2·2 ± 0·08) but not between their initial knee angles or their maximal knee angles. Independent t-tests showed a difference (P < 0·001) between the maximal passive torque of the men (41·4 ± 5·7 Nm) and women (27·4 ± 7·7 Nm). The torques were not different when standardized to body mass. Although ANOVAS showed that the absolute hamstring muscle lengths differed between genders, they were not different when standardized as a percentage of the femur length.