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 on the push-up is all about stability. Your chest and core have to struggle to balance your body weight on an unstable base: two balls, either of which might roll away. Fun!
Take up a plank, or push-up, position on the floor—arms extended with hands directly below your shoulders, and legs, hips, back, shoulders, and head all in a straight line. Take your feet wide for stability. Place each hand (carefully, and one at a time) on a medicine ball, such that your plank position is now on top of the balls rather than the floor. You must stabilize this position through your core, supporting yourself through your center without letting your hips drop toward the floor or pike toward the ceiling (see Photo 1).
- From the starting position, do a push-up, lowering your chest toward the floor as you balance over the balls. At the bottom of your push-up, your chest should be slightly below the level of your hands, so that this push-up will be deeper than an ordinary push-up. As you lower through your chest, stabilize through your core to prevent your body from drooping and to prevent your arms from pushing the balls away (see Photos 2 and 3).
- From the bottom of your push-up, press back up to the starting position, again being careful to use your abs and core to prevent the balls from spinning out to the sides (see Photo 4).
- Repeat for a full set of push-ups. If at any point in the set you want to add difficulty, you may bring your feet closer together, making it harder to stabilize.