Study Summary

43 adults with chronic unilateral rotator cuff-related shoulder pain were randomized to exercise into pain or exercise without pain, with 41 participants were analyzed. The primary clinical outcome of the original trial was the Shoulder and Pain Disability Index (SPADI); this secondary analysis study evaluated ultrasonographic outcomes including acromiohumeral distance, coracohumeral distance, supraspinatus thickness, long head of the biceps thickness, subscapularis thickness, acromiohumeral distance at 60°, coracohumeral distance at 60°, and occupation ratio. Outcomes were assessed at baseline, 9 weeks, 12 weeks, and 6 months. Overall, the results of the study revealed no significant group interaction for any ultrasonographic outcome. Although the painful exercise group demonstrated larger acromiohumeral distance and supraspinatus thickness across time, these differences were minimal and not clinically significant. Changes in SPADI and ultrasonographic parameters were not correlated. These findings suggest that painful vs. pain-free exercise does not meaningfully alter subacromial or tendon morphology in chronic rotator cuff-related shoulder pain.