The rotator cuff is a group of four muscles that surround and protect your shoulder joint. They’re particularly delicate and susceptible to injury. If you can’t raise your arm, you may have a rotator-cuff tear. The rotator cuff can tear if your arm is violently pulled or twisted or if you fall with your arm outstretched.
The most likely cause of rotator-cuff injuries is damage from repetitive movements such as throwing, catching, swimming, and lifting weights that are too heavy. Which movements cause pain depends on which rotator-cuff muscle you damage and how badly you injure it. Rotator-cuff tears are often the reason for the early retirement of baseball players and weekend softball players alike.
Rotator-cuff injuries usually are treated with ice and compression, plus strength-training exercises using very light weights. Ease up on hard-core weight-training exercises, particularly heavy bench pressing, both on a flat and an incline bench, and ask a trainer to check your form. Also, reeducate yourself on throwing, catching, or swim stroke technique — make sure to involve your entire body rather than just your arm and shoulder.
In some cases, the rotator cuff is too far gone to strengthen through exercise, and the damaged muscle needs surgical repair or, at the very least, physical therapy.