HOW: Laying on your back, bring your elbow up and straight out from your shoulder on the ground. Hold the dumbbell straight up creating a 90 degree bend at the elbow. Slowly rotate the shoulder back and forth keeping that 90 degree bend in the elbow.
FEEL: You should feel the rotator cuff muscles in the shoulder work the most.
COMPENSATION: Don’t let the elbow straighten away from your body and don’t bring it too close to your body. Try to maintain PURE rotation around the shoulder!