Place your ball on your left side, and start bending your left leg in front of you. Make sure to keep your right leg behind you. Thus, place your left hand on the ball with your elbow slightly bent. Then, extend your right arm out to your side at shoulder level. Make sure to keep your abs firm and roll the ball out to the left as far as you can while reaching your right arm over your head. Hold the position for about three seconds, then roll the ball back toward your body and return to the starting position. Make about 20 reps and then switch sides and repeat.