Rotator Cuff Anatomy

What is the Rotator Cuff?

The rotator cuff is a group of 4 muscles, the Subscapularis, the Supraspinatus, the Infraspinatus and the Teres Major. This group of muscle work together to keep the humeral head centred in the Glenoid cavity of the scapula. The Subscapularis draws the Humerus forward in the Glenoid cavity as well as providing internal rotation, the Infraspinatus and Teres Major reverse this process by drawing the Humerus back in the Glenoid cavity and provide external rotation. The Supraspinatus helps to draw the Humerus upward in the Glenoid cavity and provides the first degrees of motion in abduction.   

Dysfunction of the Rotator Cuff

Failure of one or multiple muscles in their intended function of keeping the humeral head centred in the Glenoid cavity can cause significant problems for the competitive swimmer. If the humeral head can migrate forwards, then over time this can develop overuse injuries such as Subacromial Impingement caused by secondary mechanisms along with the instability of the Glenohumeral ligaments at the front of the shoulder. This is common in swimmers with poor or no land training in their programmes and poorly designed swimming training.

If the humeral head is not centred in the Glenoid cavity this can cause more overuse injuries such as an Internal Impingement in which the Rotator Cuff tendons can become encroached between the humeral head and Glenoid rim, among a plethora of other injuries.

Resistance bands are essential for healthy shoulders.

Training the Rotator Cuff

Typical exercises for the rotator cuff do help to increase the force production and work capacity of the rotator cuff muscles and tendons, however, these exercises miss the point of the true function of the rotator cuff because everyone gets caught up on the ‘rotator’ part of the name. Remember, the true function of the rotator cuff is to keep the humeral head centred in the Glenoid cavity, not to just simply rotate the arm, this is more of a secondary function.

These exercises include generic rotation exercises on the arm, usually with the upper arms pinned to the sides. Clearly, the shoulder can move in a huge range of motion, so training the neuromuscular system in one fixed position is of limited value to a swimmer who requires the rotator cuff to function optimally during swimming. Training should be aimed at challenging the ability of the rotator cuff to keep the humeral head centred during dynamic movements that address a full range of motion. Here coaches must be creative to solve this problem and produce a thorough and optimal training programme for their swimming athletes.