I think this chair is very entincing. Those seats don't roll away like a plain ball does and look like they belong in an office environment as opposed to a gym. But when I checked with a PT I was told some reasons to stick with the ball. The arms aren't really useful. One can continue dong the Edgelow exercises while on a regular ball but not the chair. Doing these exercises occasionally while sitting can extend the time of sitting. Active sitting is strengthening. I just saw a new option. It is a ball made now with a bag of sand inside that makes it so the ball won't roll away. It is made of a very thick material with a matte finish. I was told the one I tried was purchased at Target and comes in several sizes. I haven't yet looked for it myself.