This challenging version of the original Pilates exercise One Leg Circle targets the core and increases strength and flexibility of the hamstrings. Be sure to modify your range of motion as necessary to maintain control given the instability the ball adds! Please visit http://www.PilatesOnFifth.com (for more info), http://www.UltimatePilatesWorkouts.com (for more videos) and http://www.Shop.PilatesOnFifth.com (for store).