The shoulder complex is by far one of the most fascinating structures in the body because it has an amazing range of motion, but this all comes at the expense of stability. Many of us have probably experienced some degree of shoulder pain during exercise, and wrote it off as simply being exercise-related. However, that same shoulder may have started to become achy, lasting hours even after the exercise, or the range of motion of the arm became limited. It’s usually at this point where patients present clinically, wondering “which muscle they can stretch out or strengthen” to avoid this discomfort. The answer, once again is not simple, due to the complexity of the shoulder complex. This article will look at the basic structure of the shoulder complex and how the athlete may be able to prevent shoulder injuries, including training considerations.