Grasp a secure object
behind you to steady yourself while supporting
your
upper back on a stability ball.
Leg raises, knee
raises and reverse crunches can be done
this way.
Having to balance on a stability ball
forces the abs
to work very hard to stabilize the body
during all
movements.
A dumbell, as used in the photos, bands
or
a cable pulley attachment can be used
to add
resistance.