External shoulder rotation exercises are done to work the rotator cuff. The rotator cuff consists of four muscles. They include the supraspinatus, infraspinatus, subscapularis, and teres minor. Each muscle works to rotate the arm externally (laterally) and internally (medially). The following are instructions for the cable external rotation shoulder exercise:
First, adjust the cable pulley to the height of your elbow. Grab the cable handle and stand perpendicular to the direction of the cable pulley. Bend your elbow so that your forearm crosses your stomach. Next, pull the cable handle away from your body as far as you can without moving your elbow. Your arm should move in a semicircular motion, with the elbow acting as a pivot point. Be sure to keep your upper body still at all times. If you find that you are shifting your elbow or upper body, lower the weight used.
Adjust pulley to elbow height. Grasp handle, position arm across stomach.
Keep elbow still. Move handle away from body in semicircular fashion.
Return to starting point. Repeat the exercise on both arms.