Exercise Advice: Lie on your back on a mat on the floor and place your heels on the front upper edge of a large exercise ball. By doing this, your back will actually be lifted off of the floor and only your upper back and the back of your shoulders will be on the floor. In a slow and controlled fashion, bring your heels toward your body so as to roll the exercise ball underneath your legs. Move your heels and the exercise ball about 6 – 12 inches and then return your legs to the fully extended start position. Repeat until you have performed the desired amount of repetitions.