A. The use of balls and wobble boards has become very popular in the last few years. Training in an “unstable environment” is supposed to improve your balance and strengthen the “core” muscles.
There are some exercises which are made more effective when you do them on a ball. Studies show that abdominal crunches on a swiss ball, for example, work your abs harder than the same movement done on the floor.
But there are some exercises which are not suitable for doing on a ball. We’ve seen people doing movements like the dumbbell chest press and shoulder press on a ball. The problem is that you’ll need to use a far lighter weight than normal, as you have to work so hard to keep your balance.
Remember that your muscles grow bigger and stronger when you force them to do more work, either by lifting a heavier weight, or by doing more repetitions with the same weight.
The end result of doing these exercises on a ball is that your muscles miss out on the growth stimulation they need. Remember that you only have a limited amount of time and energy to spend in the gym. Don’t waste half of it trying to do squats on a wobble board.
Reference
Vera-Garcier, F.J., Grenier, S.G., & McGill, S.M. (2000). Abdominal muscle response during curl-ups on both stable and labile surfaces. Physical Therapy, 80, 564-569
