This exercise is perfomed on a special apparatus designed for this movement.

 

Face forward as pictured, and hoist yourself up between the two parallel bars. Support yourself in this position with your legs straight. Bend your knees and pull you thighs upward so that they are parallel to the floor. This is the starting position.

 

Next, crunch your thighs toward you midsection as far as possible. Use the strength of your abdominals as you perform the exercise, not your lower back muscles. Then lower to the starting position, controlling the downward movement with your abdominal muscles.

 

Repeat the exercise for the recommended number of sets and repetitons.