This exercise provided courtesy of Billy Polson, founder and co-owner of DIAKADI Body training gym, voted best personal training gym in San Francisco by CitySearch in 2006.
Simply holding a plank, or push-up, position is a tough workout for your core. This variation doubles the difficulty by asking you to hold that position with one arm at your side. To stay parallel to the floor you'll have to stabilize through your shoulders and center in an isometric exercise that will push you as far as anything with a barbell ever could.
Take up a push-up, or plank, position on the floor: face down with your weight on your hands and toes, hands under your shoulders, and maintaining the natural 'S' curve in your spine. Stabilize your core and engage your butt muscles to ensure proper form. The closer your feet are together the more difficult the exercise; to make it easier, take your feet wide (see Photo 1).
- From the starting position, take your left hand off the floor and hold it lightly along your side while maintaining the plank position, with your shoulders and hips parallel to the floor. Continue to engage your core, keep your hips square, and do not tilt. Hold this position for 30 seconds (see Photo 2).
- After 30 seconds, bring your left hand back to the floor and switch sides, bringing your right arm up and holding it along your side as you maintain your plank position. Hold for 30 seconds on this side as well, and then return to the starting position (see Photos 3 and 4).