The socket of the shoulder is a relatively unstable joint. A piece of cartilage called the labrum forms a cup for the end of the arm bone — called the humerus — to move and helps with stability. When the muscles that surround the shoulder joint produced unbalanced tension, the labrum can become damaged. Stretching and strengthening the musculature of the shoulder can protect the labrum and promote optimal shoulder function. Before exercising or stretching your shoulders, warm up with five to 10 minutes of aerobic activity like walking or jogging.
Shoulder Joint Anatomy
Your shoulder is surrounded by muscles, tendons and bursae designed to give it its diverse range of motion. The rotator cuff muscles enable you to do large motions like throwing a baseball, serving a tennis ball, or swimming. When the internal rotators are tighter or looser than the external rotators, you place stress on the structures of your shoulder, including your glenoid labrum. The labrum is like a washer that secures the "ball" of your humerus, or arm bone, into the shoulder glenoid, or socket. To balance muscle tension and protect your labrum, stretch your internal and external rotators.
Gently taking your shoulder joint through its normal range of motion will loosen tight muscles. Lean forward from your hips and place one hand on a counter or table for support. Keeping your chest lifted and your back flat, let your other arm hang freely at your side. To enhance the effect, grasp a light dumbbell or kettle bell. Gently swing your arm forward and back for five to ten repetitions. Repeat the exercise moving your arm side-to-side, and then make circles, inward and then outward. Repeat the entire sequence with the other arm.
External Rotaor Static Stretch
To stretch the external rotators, stand erect with a lifted chest, shoulders pulled back and down. Lift your right arm to the side until it is parallel to the floor. Without rotating your trunk, draw your arm across your chest, placing the palm of your right hand just above your elbow. Apply gentle pressure until you feel a stretch at the back of your shoulder. Hold for 30 to 60 seconds, then repeat to the other side.
Internal Rotator Static Stretch
To stretch the internal rotators, stand erect, chest lifted. Lift both arms to the side until they are parallel to the floor. Turn your palms to the ceiling and squeeze your shoulder blades together as you draw your arms backward until you feel a stretch at the front of your shoulders. Return to your cruciform position and turn your palms downward until they face backward. Draw your arms back until you feel a stretch. Hold for 30 to 60 seconds.