Effects of Stretching the Upper Limb on Throwing speed and Isokinetic Shoulder Torques

Abstract

0937 Exercise is commonly preceded by warm-up and stretching routines. Although stretching has been documented to increase range of motion, recent studies have shown little effect of stretching on injury rates and adverse effects on high-force muscular performance. Strength deficits following stretching have also been found on slow isokinetic movements but not on higher velocities. PURPOSE: To determine the effects of static stretching of upper limb muscles on overarm throwing speed and isokinetic torque of shoulder internal rotators at two velocities (3.14 and 5.24 rad×s−1). METHODS: Forty subjects were randomly assigned into control and stretching groups. The experimental protocol consisted of 2 test sessions scheduled a week apart. Subjects in the experimental group performed static stretching (St) exercises to their dominant limb in one of their sessions and no stretching in the subsequent session. The order of the sessions, St or no-stretch (NSt), for the experimental subjects was randomized. Subjects in the control group did not stretch in either of their two sessions. Following warm-up and St or NSt, subjects were tested for throwing speed and concentric isokinetic torque of the shoulder internal rotation musculature at two velocities. Throwing speed was measured with a radar gun and shoulder internal rotation torques were measured with an isokinetic dynamometer. Speed and torque comparisons were made using two-way ANOVAs with repeated measures. RESULTS: Significant interactions were found for throwing speed (F = 18.96, p = .000) and isokinetic torque at 3.14 rad×s−1 (F = 5.01, p = .031), but not for isokinetic torque at 5.24 rad×s−1 (F = 4.07, p = .051). CONCLUSION: The results of this study indicated that static stretching produced a significant decrement in high-speed throwing performance and shoulder concentric torque at 3.14 rad×s−1. This result is in agreement with numerous studies that have shown stretching prior to engaging in a dynamic activity results in significant decreases in maximal muscular performance. These findings suggest that stretching prior to physical activities that contain multi-segment highspeed muscle actions, like throwing, may have a detrimental effect on performance.