INFLUENCE OF MUSCLE FATIGUE ON SHOULDER PROPRIOCEPTION

Abstract

Background: Proprioception plays an important role in shoulder JOint function and stabilization, while muscle fatigue may alter proprioceptive ability. Purposes: To investigate the influence of muscle fatigue and sex difference on shoulder proprioception. Study Design: A pre test post test design. Materials and Methods: Thirty normal subjects from both sexes were involved, age ranged between 18-25 years. The subjects were divided randomly into two equal groups, fifteen subjects in each group, group A included male subjects while group B included female subjects. Subjects in both groups received fatigue exercises on Biodex isokinetic dynamometer until peak torque of external rotator muscles dropped to 50% of the initial torque. The proprioceptive accuracy was measured pre fatigue and immediately post fatigue exercise. Results: It was found that the proprioceptive accuracy of shoulder joint was decreased significantly after fatigue exercise in both groups where (p=O.Ol) and (p=0.008) for group A and B respectively. There was no significant difference in the shoulder joint proprioceptive accuracy between both groups pre and post fatigue exercise where (p= -0.49) and (p=0.62) consequently. Conclusion: shoulder joint proprioception is diminished in the presence of shoulder muscle fatigue, suggesting clinical rehabilitation protocols should emphasize increasing muscular endurance.