Lie faceup with knees bent and feet flat on floor. Bring heels close enough to butt that you can brush them with your longest fingertip. Grab dumbbells. Lift arms up and over, lowering them behind head while lifting hips into air. Once backs of hands touch floor, slowly reverse the move, lowering hips. Repeat 5 times. Hug knees to chest and rock side to side, massaging back.