Kneel on the floor grasping the cable from above. (see movie) Perform
an abdominal compression and curl downward flexing from the spine.
Do not go past 30-40 degrees flexion. Do not hold your breath.
The mechanics of this exercise are similar to a crunch, with the
amount of resistance being dictated by the cable machine as opposed
to gravity. The range of motion should be the same as if you were
on the floor. Avoid flexing the spine beyond 30-40 degrees, to prevent
shifting the muscular effort from the abdominals to the hip flexor
Using too much resistance. Only use resistance which can be controlled
with proper form and technique. Be sure to go slow and concentrate
on moving the weight with your abdominal muscles instead of your
arm or hip flexor muscles.