Time course of changes in the range of motion and muscle-tendon unit stiffness of the hamstrings after two different intensities of static stretching.

Abstract

ObjectivesThe purpose of this study was to examine the time course of changes in the range of motion and muscle-tendon unit stiffness of the hamstrings after two different intensities of static stretching.MethodsFourteen healthy men (20.9 ± 0.7 years, 169.1 ± 7.5cm, 61.6 ± 6.5kg) received static stretching for 60 seconds at two different intensities based on the point of discomfort (100%POD and 120%POD) of each participant, in random order. To evaluate the time course of changes in the flexibility of the hamstrings, the knee extension range of motion (ROM), passive torque at end ROM, and muscle-tendon unit stiffness were measured pre-stretching, post-stretching, and at both 10 and 20 minutes after static stretching.ResultsFor both intensities, ROM and passive torque at pre-stretching were significantly smaller than those at post-stretching (p ConclusionThe results showed that ROM and passive torque increased in both intensities, and the effects continued for at least 20 minutes after stretching regardless of stretching intensity. However, the muscle-tendon unit stiffness of the hamstrings decreased only after static stretching at the intensity of 120%POD, and the effects continued for at least 20 minutes after stretching.