Thoracic Rotation

START: Get down on all fours. Brace your core—imagine that you are about to get punched in the gut.

MOVEMENT: Place your right hand behind your head with your elbow pointing out to the side. Rotate your right shoulder toward your left arm until your elbows touch. Follow your elbow with your eyes as you reverse the movement until your right elbow points toward the ceiling. Open up your chest. Your left arm should stay straight and strong. That's 1 repetition. After you have completed the prescribed number of reps, switch arms and repeat.