Exercise Advice: Lie face up with exercise ball under your lower back. Hold a medicine ball and place your arms straight up over chest. Hold your body in a straight line from hips to knees, knees at a 90 degree angle. Tightening your glutes and abs, slowly twist your body to one side, sweeping arms parallel to the floor, then back up, repeating on the other side. Keep your hips straight (don’t turn them when you turn your body) and abs pulled in.