Leg Tucks on the Floor Show Video Show All Exercises     Lie on your back with your hands at your temples. Lift your upper body as if doing a sit-up. Simultaneously, bring your knees up as far as possible towards your chest. Try to touch elbows to knees. Lower your back to the starting position. For best results, perform this exercise in one slow and controlled motion. Here are a few suggested alternative exercises: Ab Crunch Ab Crunch Obliques Ball Crunch Traditional Double Crunch Dumbbell Side Bends Lateral Bend with Barbell