Preventing Shoulder Injuries - Workplace Health

Have you ever wondered how baseball pitchers can have such different throwing motions and create so many variations of a pitch? It's the shoulder, an amazing joint that can make the arm throw overhand or underhand at almost 100 miles per hour, and seconds later make full circles frontward or backward. But the feats performed by this most mobile joint in the body stress the shoulder in ways that make it prone to injury.

The shoulder joint is often thought of as a golf ball sitting on a tee: The large, rounded end of the humerus (upper-arm bone) moves within the scooped out glenoid head (or socket of the scapula bone in the back) next to the end of the clavicle (collarbone). But unlike a golf ball that is launched from a tee, the head of the arm must remain in a confined space and still move freely. A complex of multiple tendons attached to muscles, with support from ligaments, makes this happen without us having to give it a conscious thought.

Shoulder injuries can be caused by various activities that involve excessive overhead motion, such as swimming, tennis and baseball, but they also occur when people perform less strenuous household chores and hobbies, such as washing windows and gardening.

Pain is the most common symptom of shoulder injury. Variable degrees of stiffness and a locking sensation may occur with or without pain. Sometimes a shoulder injury can lead to numbness or tingling down the arm.

If you have injured your shoulder, pain is a useful indicator to guide how much to use it. Unless your doctor or physical therapist gives you other instructions, limit activities and arm motions that are aggravating the pain. Here are some specific suggestions to help minimize the pain:

Eliminate heavy lifting and raising arms above shoulders.
Lift items close to the body.
Lift only light weights, below shoulder level.
If swimming, do the sidestroke or breast stroke.
Throw balls underhand or sidearm.
If playing tennis, do not serve overhand.
Practice good posture with computer work, assembly work, or other activities that involve your arms.
Limit the amount of time that you restrict arm movement with a sling, as you may develop frozen shoulder (stiff shoulder joint).

Keeping physically fit with a balanced program of aerobics, stretching and strengthening all your body parts helps to prevent shoulder injuries. If you think you have injured your shoulder, consult a physician or physical therapist before starting an exercise program. Here are some specific tips for the shoulders:

Apply heat to shoulder muscles before exercise. Heat prepares muscles and tendons for exercise. For example, take a warm shower for 10 to 15 minutes before exercise.

Keep your arm below shoulder height while doing stretches for the shoulder.

Gradually increase movements — big circles, across-body movements, trunk twists, shoulder blade rolls and forward and backward squeezes — during shoulder warm-up.

Pendulum stretching exercises relieve pressure on the rotator cuff. While sitting or standing, keep arm vertical and close to the body. Allow arm to swing back and forth in a small diameter (about 1 inch). As symptoms improve, the diameter of swing may be increased. Initially perform the exercise with just the weight of your arm. As shoulder pain improves, progressively add more weight — 5 to 10 pounds (a filled gallon container weighs 8 pounds). Perform exercise for five minutes once or twice a day.

Muscle-strengthening exercises: If you have sustained a shoulder injury, begin shoulder-muscle toning exercises about one to two weeks after doing pendulum stretching exercises. Use elastic exercise bands for a variety of arm exercises. For example, attach band to a doorknob. Then hold your elbow close to your side at a 90 degree angle, grasp the band and pull toward your waist. Hold for five seconds. Do 15 to 20 repetitions each day.

Paulette Chandler, M.D., M.P.H., is a clinical instructor of medicine at Harvard Medical School and an attending physician at Brigham and Women's Hospital.