Pilates: Roll Back and Up

Sit with your legs extended straight out in front of you, feet flexed. Hold the ball in front of you at shoulder level, arms straight. Keep your chest up and back straight. Contract your core and glutes, then slowly roll back until your back is flat on the floor and the ball is directly overhead. From that position, bring your chin to your chest and slowly roll back up to the starting position. That's one rep.