If you are dealing with shoulder pain than strengthening the rotator cuff, aka the dynamic stabilizers, is a must! Typically, you will find exercises working these muscles with the arm at the side. This is a great place to start but the rotator cuff needs to be trained in a range of motion where pain typically occurs. Prone Shoulder ER @ 90 Degs is effective because it focuses infraspinatus recruitment with relatively low deltoid and trap activation. This is important because infra needs to be f