A Comparison of 2 Exercise Protocols in Athletes With Primary Subacromial Impingement Syndrome: A Randomized Clinical Trial

Context: To stabilize the humeral head within the glenoid fossa during arm elevation, the rotator cuff muscles may contribute through internal and external rotation. The main purpose of the current study was to compare the acromiohumeral distance between athletes with primary subacromial impingement syndrome who received progressive resistance exercises consisting of either shoulder internal or external rotation. Design: A randomized and controlled clinical study. Methods: Thirty athletes with primary subacromial impingement syndrome were enrolled and randomly divided into 2 experimental groups. The progressive resistance exercise protocol in experimental group I comprised shoulder internal rotation, while in experimental group II consisted of shoulder external rotation. The experimental groups worked out 3 days a week for 6 weeks. The experimental groups were compared with the control group consisting of 15 healthy athletes. The acromiohumeral distance was measured before and after the intervention using an ultrasound machine under the passive and active across no arm elevation and 45 degrees of arm elevation. Results: The acromiohumeral distance significantly increased in both experimental groups under the passive and active arm positions following the intervention (P < .001), with no significant differences detected between the experimental groups (P> .665). The paired comparisons of the acromiohumeral distance discrepancy indicated a significant difference between the control group and each experimental group under the active and passive arm positions (P < .001), while no significant difference was observed between the experimental groups (P > .999). Conclusions: The present study revealed, for the first time, that both progressive resistance exercise protocols involving either the shoulder internal or the external rotation increased the acromiohumeral distance in individuals with primary subacromial impingement syndrome and improved associated pain and disabilities.