The action of throwing requires an athlete throwing overhand to “cock” the shoulder back. When this motion is repeated, soft tissues can get squeezed between the bones of the shoulder, causing the underside of the rotator cuff tendon to rub. When this happens, the athlete may begin to feel stiffness in the shoulder, even after a good warm up. The shoulder pain is usually vague at first but is pinpointed to the back part of the shoulder as the problem gets worse. Pain is most noticeable as the arm is cocked back to throw and when the arm starts to come forward.
The same pain can be reproduced when an examiner puts the shoulder into the cocked position. Other tests, such as MRI scan, may also be required to see if the rotator cuff is rubbing. If the problem is detected early, the athlete is treated by resting the shoulder for one month and then starting a strengthening program for the rotator cuff and the muscles around the shoulder blade. Shoulder surgery may be needed if the athlete has had the problem for a while, shows a positive MRI, and has not gotten better with rest and exercise.