Basic Crunch
Key Points
Initiate the crunch by moving your rib cage, NOT by moving your head. Your head comes along simply because it is connected to your rib cage.
Drop the front of your ribs down so that your mid-back presses strongly into the floor.
Tone your lower abs and pull your lower belly up toward your heart. DO NOT pooch your belly up toward the sky or down into your pelvis.
DO NOT pull your belly button aggressively to your spine.
DO NOT squeeze your butt aggressively as you crunch up.