Swimming Anatomy

The shoulder protector group, also known as the rotator cuff, is made up of the supraspinatus, infraspinatus, teres minor, and subscapularis (figure 3.2). The supraspinatus lies along the top part of the shoulder blade and attaches to the head of the humerus. The primary role of the supraspinatus is to help initiate overhead movements of the arm. The infraspinatus and teres minor arise from the back part of the scapula and attach next to the supraspinatus on the head of the humerus. The infraspinatus and teres minor act to rotate the shoulder externally. The subscapularis muscle runs along the front part of the shoulder, and like the other rotator cuff muscles, it originates on the scapula and inserts onto the head of the humerus. As the name implies, the primary action of the rotator cuff muscle group is to perform rotational movements at the shoulder joint. Because of the smaller sizes of these muscles, their contribution to the propulsive forces generated while swimming are relatively small; they do, however, have an important role in aiding in the recovery phase of all the strokes. Another vitally important role is their “cuff” function, which stabilizes the shoulder joint. When considering the role of the rotator cuff in stabilizing the shoulder joint, remember that the shoulder is a ball-and-socket joint that resembles a golf ball sitting on a tee. The rotator cuff muscles act as dynamic stabilizers by creating opposing forces that keep the ball centered on the tee. In some instances an imbalance can arise amongst the rotator cuff muscles, which inhibits their stabilizing mechanism and in turn increases the risk of injury. The shoulder joint sacrifices stability in favor of mobility and therefore depends on the rotator cuff muscle group to act as stabilizers and protectors.

Figure 3.2 Shoulder blade and neck.

The next major muscle group is the positioner group, which is actually only one muscle that has three separate divisions—anterior, middle, and posterior. The deltoid is the shoulder cap muscle that drapes over the upper portion of the shoulder joint (figure 3.3). The deltoid is called the positioner group because it is the primary muscle involved in changing the position of the humerus and thus the entire arm. The anterior portion is responsible for flexing and internally rotating the shoulder joint. The posterior portion performs the opposite movements, extension and external rotation. The middle portion is responsible for lifting the arm to the side, which is the movement of abduction. The deltoid is most active during the recovery phase. Each portion plays an important role in moving the arm during the various stages of the recovery phase.

The final muscle group, the propellers, includes the latissimus dorsi and pectoralis major. This name is derived from the fact that these muscles are the primary force generators at the shoulder joint. Because of the large number of exercises that target these muscles, their contributions to the movement of a swimmer and associated exercises will be reviewed in the chapters covering the chest and back.

Figure 3.3 Deltoid.

Forward Dumbbell Deltoid Raise

Execution

1. Stand and hold a dumbbell in each hand with your arms hanging at your sides and your palms facing your thighs.

2. Holding a slight bend in your elbows, raise the right dumbbell forward until it is level with your shoulders.

3. As you raise the dumbbell, slowly rotate your hands so that your palm faces the floor at the end of the exercise.

4. As you begin lowering the right dumbbell, initiate the movement of the left dumbbell.

Muscles Involved

Primary:Anterior deltoid

Secondary:Middle deltoid, trapezius, pectoralis major (clavicular head)

Swimming Focus

The anterior deltoid, the primary muscle engaged throughout this exercise, is a key player in the recovery process of butterfly, breaststroke, and especially backstroke. During butterfly it is active during the second half of the recovery, and during breaststroke it contributes by guiding the movements of the arm and hand from underneath the swimmer’s chest to a fully extended and elongated position, maximizing the efficiency of the stroke. The entire recovery phase of backstroke, from water exit until reentry, also relies on recruitment of the anterior deltoid. As the speed of the stroke increases and the need for rapid recovery increases, so does the demand placed on the muscle.

You can use this exercise to build on the scapular setting motion previously described. To do this exercise, stand with a tall, upright posture and focus on pinching your shoulder blade backward and downward. While holding it in this set position, perform the exercise. Have a partner monitor your movements from behind to make sure that you do not start to shrug your shoulders.

VARIATION Forward Deltoid Raise With Tubing