Acute effects of combined static stretching and electrical stimulation on joint range of motion and passive stiffness

Abstract

This study aimed to determine the acute effects of combined static stretching (SS) and electrical stimulation (ES) on joint range of motion (ROM) and passive muscle and tendon properties. Sixteen healthy men participated in two randomly ordered experimental trials, which comprised a combination of SS and ES (SS + ES), and SS alone. In the SS + ES trial, participants performed 5 minutes of calf stretching while receiving ES of the gastrocnemius medialis, whereas in the SS trial the participants performed calf stretching only. Maximal dorsiflexion angle, passive torque, and displacement of the muscle-tendon junction were measured before and after intervention. The stiffness of the muscle and muscle-tendon unit was calculated. Compared with the pre-intervention values, there were significant increases in ankle ROM and passive torque at maximal dorsiflexion angle after both interventions. In addition, the passive torque at the submaximal dorsiflexion angle and stiffness of the muscle-tendon unit were significantly decreased after both interventions. However, none of the assessed parameters significantly differed between the SS + ES and SS trials. These results show that 5 minutes of SS increases ankle ROM and changes the passive properties of the muscles. However, there is no additional effect of adding ES to SS.