The external rotation muscles of the shoulder make activities like washing your hair and throwing a ball possible. Training them will provide stability to the shoulder joint and help your posture. A variety of exercises strengthen these important muscles is important the external shoulder rotation is one of your options.
Stand beside a cable pulley at elbow height. Grasp the handle with the arm further from the pulley. Hold elbow tight against your side with the forearm in front of your belly. Pull the cable away from the body by externally rotating the shoulder. Return to the starting position and repeat.
*Tip: You can use a towel under the arm to help with stabilization, though this is not necessary.
Allowing elbow to pull away from the side or completing only part of the full range of movement.
Infraspinatus, Teres Minor, Posterior Deltoid.
Replace the cable pulley with a resistance band anchored at elbow height.