Twist Crunches work well for me. 1. Lie on your back with your knees bent. 2. Carefully lift your head up and place your hands behind your head without locking your fingers together. 3. Twist to the right bringing your left elbow to your right knee. Extend your left leg out. 4. Now twist back to the left bringing your right elbow to your left knee. Extend your right leg out. 5. Repeat 25 times.