Seated Circles on the Stability Ball targets the deep stabilizers of the lumbar spine and activates the core. Range of motion can be modified to make it easier or a bit more challenging according to your clientsâ needs. Please visit http://www.PilatesOnFifth.com (for more info), http://www.UltimatePilatesWorkouts.com (for more videos), http://www.Shop.PilatesOnFifth.com (for store) and Click HERE for class schedule.