You use your shoulder joint on every stroke, so keep it healthy by learning some new habits.

There’s no denying a shoulder problem when you reach up to serve. Just ask Maria Sharapova, who missed nine months recovering from an injury to that joint. It required surgery and forced her to shorten her service motion.

The powerful overhand thrust and rapid deceleration of a serve can overload the shoulder, which, unlike other joints, has only a few ligaments and a thin capsule to keep it stabilized, according to Todd S. Ellenbecker, clinical director at Physiotherapy Associates Scottsdale Sports Clinic, in Scottsdale, Ariz., and chairman of the USTA Sport Science Committee. The shoulder’s main support comes from the four rotator cuff muscles. The problem is, since the shoulder joint has more range of movement than any other in the body, the tendons that connect these muscles can be overloaded and injured from tennis strokes. In fact, a typical player’s dominant shoulder tends to be weaker than the nondominant shoulder. “This is likely from the stress during the follow-through of the service motion,” Ellenbecker says.

Injuries to the rotator cuff can be anything from irritations to tears, causing pain and a reluctance to put much on your shots. Fortunately, tennis players can avoid searing pain by getting into a few simple habits.

Habit 1: Be cautious

“One of the main causes of shoulder injuries in tennis is overuse, which is too much play either over a long period or even a short period,” says Dr. W. Ben Kibler, medical director of the Shoulder Center of Kentucky in Lexington and a member of the USTA Sport Science Committee. Stop playing when you feel even a twinge in your shoulder. If stopping is unrealistic, don’t compound the problem by playing through any recurring pain the next time you hit the court. Rest is good; an off day is not a defeat.

Habit 2: Get evaluated

It may sound impressive that the shoulder has the largest range of motion of any joint in the body, but it’s also the least stable and most sensitive, Ellenbecker says. To put spin and pace on the ball when you’re serving, your shoulder might rotate 120 degrees or more. According to research published by Kibler and his colleagues, a pro torques up to an incredible 180 degrees to get those triple-digit readings on the radar gun. What you want to avoid is pulling and twisting your shoulder too far back on the serve. A teaching pro can help by evaluating your technique; if an instructor sees a problem, he or she can help you correct the motion.

Habit 3: Take care

Keep your shoulders pain-free and ready for the court by caring for them properly. Warm up before you play, stretch regularly and do some strength training to build up the muscles around the joint. To warm up, do dynamic stretches like arm circles and full-body moves that involve the torso and arms.

Research from the Medical College of Georgia in Augusta shows that regular strength training with lightweight dumbbells and elastic resistance bands can increase both shoulder strength and serving speed. Ellenbecker recommends “prehabilitation” exercises with no more than 1.5- to 2-pound weights.

To increase flexibility and prevent pain in the muscles of the rotator cuff, Ellenbecker suggests doing the posterior shoulder capsule stretch after you play. Make it a habit to stretch your shoulders at least three times per week, or better yet, every day.

Originally published in the November/December 2009 issue of TENNIS.