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.
Don't let the name scare you away from this tried-and-true triceps builder. Proper focus on technique and use of appropriate weights will keep you from bonking yourself on the head when doing skull crushers. Using the stability ball as your "bench" when doing this exercise adds additional difficulty because it forces you to focus on balance and core form, which means a better overall workout and stronger triceps in the long run.
With dumbbells in each hand, lie back on a stability ball so that your body weight is evenly distributed across your upper back. Your back should be touching the ball between the top of your lower back and the bottom of your neck; your head should also be resting on the ball. Extend your feet out until your knees are bent at close to a 90-degree angle and are firmly planted on the floor, hip-width apart. Your hips and thighs should be parallel to the floor—squeeze your glutes fully thoughout the movement to hold your body's position on the stability ball.
Finally, extend your arms above your head and the dumbbells in your hands so that your palms are facing each other (see Photo 1).
- From the starting position, bend your elbows and bring the dumbbells down on either side of your head. To get the most work out of your triceps, try to keep your arms at a 45-degree angle throughout. You should feel your triceps engaged throughout (see Photo 2).
- When you have reached the bottom of the range of motion, reverse the movement by straightening your arms and bringing the dumbbells back to starting position (see Photo 3).