Slow passive stretch and release characteristics of the calf muscles of older women with limited dorsiflexion range of motion.

Abstract

Examine the slow passive stretch and release characteristics of the calf muscles of older women with limited dorsiflexion range of motion. A cross-sectional comparative design. The passive stretch and release characteristics of the calf muscles of older women with limited dorsiflexion range of motion have not been studied. Fifteen older women (mean 79 years) with active dorsiflexion < or =10 degrees and 15 younger women (mean 24 years) without limited dorsiflexion were tested. The right ankle was stretched from plantarflexion to maximal dorsiflexion and released into plantarflexion at 5 degrees /s with minimal surface EMG activity in the soleus, gastrocnemius, and tibialis anterior muscles. Length, passive-elastic stiffness and stored passive-elastic energy were examined. The older women had less maximal passive dorsiflexion, a greater initial stretch angle, and less angular change than the younger women (P < 0.05). The maximal passive resistive force (Newtons) of the stretch phase, and the stored passive-elastic energy ( degrees N) during both stretch and release phases were also less (P < 0.001). The older women had greater passive-elastic stiffness at 0 degrees and 5 degrees of dorsiflexion (P < 0.001). The older women had decreased calf muscle length, extensibility, maximal passive resistive force, stored passive-elastic energy, but greater angle-specific-stiffness at 0 and 5 degrees of passive dorsiflexion. Older women with limited dorsiflexion range of motion have decreased calf muscle length, passive resistive forces and stored passive-elastic energy that may impact static and dynamic standing balance activities. Greater passive-elastic stiffness within their ambulatory dorsiflexion range of motion may partially compensate for the deficits.