Rotator cuff injuries in the overhead athlete are frequently seen at all levels of competitive sports. The repetitive, high magnitude forces generated at the capsuloligamentous complex, as well as at the rotator cuff itself, can result in loss of glenohumeral stability and primary as well as secondary lesions in the rotator cuff itself. The biomechanics of overhead sporting activity (i.e., pitching, tennis) explains the tremendous load demands placed on the shoulder. These forces must be clearly understood by the sports medicine specialist before proper treatment protocols can be initiated. A fundamental understanding of the biomechanics can provide important information to maximize treatments, enhance overall performance, and accelerate a more effective and expeditious rehabilitation program. The rehabilitation of these complex injuries remains a challenge and requires a methodic, systematic approach that is goal directed and designed to fulfill specific and objective criteria before progressing to the next phase of rehabilitation. Finally, the rehabilitation must be individualized and sports specific.