As a mother of two boys on a high school baseball team, I notice there are a lot of shoulder injuries. Most seem to occur with overhead throwing. What causes this to happen?

The overhead athlete faces some unique challenges. The core muscles around the shoulder are called the rotator cuff. The rotator cuff must be strong enough to move the arm forward at high speeds without letting the shoulder coming out of the socket.

Two muscles are especially important during the overhead throw. These are the infraspinatus and teres minor, two muscles that rotate the shoulder outwardly.

Problems can occur if the joint is naturally loose or even too tight. Athletic conditioning programs often include exercises to strengthen these muscles. The idea is to: (1) increase muscle strength, (2) prevent injury, and (3) enhance performance.

Teams with high rates of injury may not be focused on exercises for all three goals.