Starting position hanging from a chin-up bar.
Beginner: Crunch your knees
until your thighs are parralel to the floor.
Intermediate: Crunch your knees until you touch your knees to your
Advanced: Crunch your lower body up until you touch your ankles
to the chin-up bar.
Note: Fatigue of the hands
and shoulders can be minimized by utilizing "Ab Slings" as shown in