Ball Side Lifts Show Video Show All Exercises     Lie face down with ball under your hips. Bend your left knee and lift up towards your chest. Finish by extending and driving your left leg behind you. Return to the starting position and repeat. Here are a few suggested alternative exercises: Ab Crunch Ab Crunch - Machine Ab Crunch Obliques Ball Crunch Traditional Double Crunch Dumbbell Side Bends Kneeling Cable Crunch Kneeling Oblique Twist Lateral Bend with Barbell