The Effect of Prolonged Static and Cyclic Stretching on Ankle Joint Stiffness, Torque Relaxation, and Gait in People With Stroke

Abstract

Continuous passive motion (cyclic stretching applied to the subject's limb) has been used for the rehabilitation of some orthopedic impairments; however, few researchers have considered its application in the management of neurological disorders such as stroke. The purpose of this study was to examine the short-term effects of prolonged static and cyclic calf stretching on passive ankle joint stiffness, torque relaxation, and gait in people with ischemic stroke. Ten community-dwelling people (mean age=64.6 years, SD=8.76, range=53-76) who were diagnosed with a cerebrovascular accident volunteered to be subjects. Participants engaged in one 30-minute static stretch and one 30-minute cyclic stretch of the calf muscle, using an isokinetic dynamometer that also collected torque and angle measurements. Before and after treatments, 10-m walking times were collected. Ankle joint stiffness was calculated from the slope of the torque and angle curves before and immediately after treatments, and torque relaxation was calculated as the percentage of decrease in peak passive torque over the 30-minute stretch durations. Ankle joint stiffness decreased by 35% and 30% after the static and cyclic stretches, respectively. Stiffness values and 10-m walk times were not different between conditions. The amount of torque relaxation was 53% greater for static stretching than for cyclic stretching. These preliminary data from a very small sample of people with stroke indicate that ankle joint stiffness decreases after both prolonged static and cyclic stretches; however, neither technique appears to be better at reducing stiffness in people with stroke. Torque relaxation is greater after static stretching than after cyclic stretching, and walking speed does not appear to be influenced by the stretching treatments used in our study.