The most important thing you can do to prevent shoulder injuries is to warn up properly and strengthen the rotator cuff muscles.
Warm up with Stretches to Reduce and Prevent Shoulder Pain
Use these exercises to strengthen the
four rotator cuff muscles. Begin with two- or three-pound weights and do 3 sets of 10 reps twice a week.
Supraspinatus, the muscle that helps the deltoid raise the arm to the side and assists with outward arm rotation.
Exercise: Hold dumbbells by your sides in a sitting position then raise both your hands straight out to the sides. Lower slowly.
Infraspinatus and Teres Minor, two muscles that help pull the arms downward (as in a pull-up).
Exercise: Lie on your side on a bench with weight in hand, your elbow touching your hip and your arm bent at a right angle. Rotate your arm upward, pivoting your elbow as you lift the weight away from the bench. Slowly lower.
Subscapularis, a muscle on the front of the shoulder blade that assists with inward rotation of the arm.
Exercise: With your elbow at your side and your forearm at a 90-degree angle, turn sideways. Turn and repeat on the opposite side.