Understanding Swim Stresses Swimming repeatedly stresses the complex shoulder joint. The shoulder's range of motion in multiple directions requires a degree of instability and little bony support. For stability, the shoulder relies on the capsule, the rotator cuff muscles, and the larger surrounding muscles such as the pectoralis major, the deltoids, the serratus anterior, and long head of the biceps. The scapula, though mobile, is the base of the glenohumeral joint and must be controlled for proper shoulder function. As these tissues become inflamed, the narrow space becomes even tighter, worsening the impingement.
Swimming brings the shoulder through at least one impingement position with each stroke.
Rotator cuff fatigue, scapular dysfunction, and shoulder laxity can contribute to impingement syndrome. The rotator cuff holds the humeral head in position and depressed against the forces of other muscles, preventing its anterior and superior translation. Weight training has classically focused on the anterior chest wall and internal rotators, while the external rotators and supportive muscles may be underdeveloped and unable to stabilize the shoulder. Greipp13 found that impingement pain increases in swimmers who increase the intensity and duration of weight training and in those who have less flexibility in the shoulder musculature. Children naturally avoid activities that cause soreness and discomfort, but they are pushed beyond discomfort in competitive athletics when they have the motivation to succeed and pressure to please coaches and parents.