Infraspinatus Isolation During External Rotation Exercise at Varying Degrees of Abduction.

CONTEXT: External rotation (ER) strengthening exercises are a common component of shoulder injury prevention and rehabilitation programs. They are primarily intended to target the infraspinatus muscle, based on its role in glenohumeral stabilization and inferior humeral glide. ER also recruits the posterior deltoid, which can be undesirable due to its role in subacromial space narrowing. OBJECTIVE: To determine the angle of humeral abduction …