extra heavy duty ball. You don't want it to fall while you have heavy weights in your hands. Last but not least, these balls are also great as an extra chair. In fact, try one at your desk, and get a bit of a workout just by sitting on it while you work. They will also help improve your posture by forcing you to not slouch.
Choosing the Right Size
When it comes to exercise balls, size matters. Your height and weight along with what you plan to use the ball for will determine which size is best. See the rough guide to sizing on the right, but remember that there are other things that might cause you to go larger or smaller. The main thing to keep in mind is that if you sit on the ball and can't touch your feet to the floor, then it's too big. Ideally, your legs should be at a 90 degree angle while sitting on it.
* The heavier you are, the larger a ball you will need.
* Regardless of height, long legs need a taller ball and short legs need a shorter ball.
* If you plan to do exercise primarily on your back, a shorter ball is a good bet.
* Always opt for the larger ball size if you fall on a cusp of one of the height categories. If the ball seems to big, you can deflate it a little. However, a ball that is too small, will always be small no matter how much you inflate it.
* If you want a very firm ball, try and go smaller if you can.
More basic suggestions about sizes...
* 65cm Good size for exercising especially if you are not tall (5' or less).
* 75cm Good size for most exercises. Some like this size for sitting at a desk.
* 85cm Very big. Some like this size for sitting at a desk.
Specific Brands and Styles
* '''Gaiam''' Nice and thick, with a nonskid surface which is useful for exercising.
* '''Arte Multi model comes in a fun multicolor swirl.