Crunches

What exercise does: Crunches work the entire abdominal area.

Implementation: (A) Lie back on the floor, your legs across a bench in front of you. Place your hands behind your neck or keep them in front of you, whatever is most comfortable for you.
(B) Curl your shoulders and trunk upward toward your knees, rounding your back. Don't lift your whole back off the floor, just roll forward and crunch your rib cage toward your pelvis. At the top of the movement, deliberately give an extra "crunch" of the abdominal to achieve total contraction, then release and lower your shoulders back to the starting position.  You have to do each rep methodically and under control. You can change the angle of stress on your abdominal by raising your foot position. In stead of putting your legs across a bench, try lying on the floor and placing the soles of your feet against a wall at whatever height feels best.