Here’s a quick shoulder exercise routine that you can do when you take the courts. All you’ll need is a resistance band and something to loop it through, like the net or a chain link fence. I like to do 3 sets of 15 reps of each exercise with each arm.
Internal Rotation: Start with your elbow just above your wrist, tight in against the body. Start with your forearm perpendicular to your torso and rotate your shoulder inward, bringing your hand across your body. Be sure to keep the elbow in close to your body and don’t use your whole arm to do the exercise. Try to isolate the small muscles in the shoulder for optimal benefit.
External Rotation: Same starting position with the elbow as the internal rotation, tight in against the body right above waist-height. Start with your forearm rotated inward up against your torso, and rotate the shoulder outwards until you get perpendicular to your torso (full range of motion). Be sure once again to keep the elbow in close and isolate the small muscles of the rotator cuff.
External Rotation at 90 degrees: Start with your upper arm parallel to the ground at shoulder height and your forearm rotated outwards at a 90 degree angle. It should look like you are throwing a punch. Using your elbow as a hinge, rotate your arm so that your fist points upwards at the sky. Try not to move your elbow and use only your shoulder muscles (not your whole arm) to complete the exercise.
These basic shoulder exercises will help build strength in the rotator cuff muscles, better stabilizing the shoulder joint and reducing the risk of injury. They are also great to do before play as a warm up.