Better? No. Different. Yes.
I would mix them up. The ball will work the stabilizers harder and will help improve balance and overall coordination.
However, it also limits the amount of weight you can use. There are probably a few people out there somewhere who can lift as much on a ball as they can on a bench, but I'm not one of them and I haven't personally met one of them yet.
So basically, it depends upon what you want to achieve from the exercise.
Also, once you start lifting higher, you must take extra precautions when lifting on a ball. If you are lifting heavy, invest in the highest quality, anti-burst ball that you can find. Also, even if you do have an anti-burst ball, check frequently for "scuffed" up areas where the there is a thinning of the ball, because if these areas wear through and anti-burst ball can still deflate rapidly and send you crashing down. Something that you definitely do not want to happen when you are using more than a minimal load.
While, this book seems to take one stance, there are other respected fitness professionals such as Mike Boyle, who will not let his athletes do more than body weight exercises on the ball because he feels the reward is not worth the risks.
I take the middle ground. Use both, but be extremely careful when using a load on the ball.
|