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.
Push-ups with one hand on a medicine ball work your chest and shoulder muscles especially hard on the lowered side. The effort required to keep you from tilting is a full-body project, engaging your core, legs, chest, shoulders, and back.
Chest, Shoulders (rotators)
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. Roll a medicine ball underneath one hand, such that the hand on that side rests on the ball rather than on the floor. In all other ways, however, your plank should be normal—do not tip side to side or droop through your center (see Photo 1).
- From the starting position, do a push-up with one hand on the ball and the other on the floor. Lower until you can feel tension in both sides of your chest. Do not tilt your shoulders—even though your hands are not level, the rest of your body should be, and your chest should descend parallel to the floor, not at an angle. You must engage your core to keep from drooping through your center. At the bottom of your push-up, the arm over the ball will be sharply bent, with the elbow to the side (see Photos 2 and 3).
- From the bottom of your push-up, press back up to the starting position, trying to keep the push even through both sides of your chest and shoulders—do not rely too heavily on the hand on the floor. Hold for one full second at the top of your push-up, so that your rotators have to work to stabilize you over the ball (see Photo 4).
- Repeat for a full set of push-ups on one side before switching the ball to the other hand and repeating another set on the second side.