This exercise provided courtesy of Mike Clausen, founder and co-owner of DIAKADI Body training gym, voted best personal training gym in San Francisco by CitySearch in 2006.
This variation of the single leg tap abs exercise uses the BOSU ball to add additional levels of stomach-crunching difficulty. You'll need constant abdominal contraction to avoiding wobbling on the ball, even as the ball itself increases the angles of the exercise, demanding a larger range of motion.
Lie on your back on a BOSU ball with the ball between your shoulder blades and hips. Extend your right arm above your head, with your palm facing the ceiling. Extend your left arm to the side and rest your hand on the floor palm-down for balance. Your left leg should be extended with your heel lightly on the floor; bend your right knee and put your right foot flat on the floor, shifted slightly toward the midline of your body as this is your balancing foot (see Photo 1).
- From the starting position, squeeze through your obliques as you bring your right arm up toward the ceiling, while simultaneously lifting your left leg straight up to vertical as well. Both arm and leg should remain straight throughout. Try to touch your left foot with your right hand at the top of your lift (see Photos 2 and 3).
- Keep the contraction through your abs as you reverse direction and lower your arm and leg back to the starting position (see Photos 4 and 5). Repeat for a full set on one side before switching sides, now bringing your left arm up to meet your extended right leg.
For a more difficult variation on this exercise, hold a dumbbell in the hand that you will be bringing overhead. Your palm should face the ceiling as you start, and your wrist remain straight as you lift. Perform the exercise as described above (see Photos 6).
About Mike Clausen: Clausen is the founder and co-owner of DIAKADI Body training gym, voted best personal training gym in San Francisco by CitySearch in 2006. He has been actively involved in sports and weightlifting since high school, and continues to use that knowledge when training his clients. Clausen is both A.C.E. and N.A.S.M. certified and has been training clients professionally for six years. He enjoys making his clients stronger, both physically and mentally, giving them the tools to create an efficient body and to do things they thought were not possible.