Most trainers and coaches prefer to have athletes perform functional exercises, rather than just push weights around. Functional exercise is generally an exercise that requires you to use your body as resistance, rather than the weight. Such exercises require more muscles to be activated (stabilizers and core muscles) during the movement. In this way a push up works more muscles than a bench press.
When you add is the requirement of balance, you also increase muscle fiber activation. During functional exercises, a machine doesn't control the movement patterns, so your muscles must control it.
Keep in mind that you should progress from the basic push up to the stability push up in order to perform it safely. Do not attempt stability push ups until you can do 20 basic push-ups.
The stability push up requires a stability ball (Compare prices on Stability Balls), and is much harder than it appears. In additional to being a great upper body and core training exercise, it's also great for shoulder stabilization.
Stability Ball Push Up Technique (See Picture).
- Lay with your chest on the stability ball
- Place your hands at the sides of your chest.
- Place your toes on the floor, legs straight.
- Push your body up until your arms are almost straight (do not lock your elbows).
- Hold and balance for two seconds.
- Slowly return to the starting position and repeat.