How does the firmness of a yoga ball effect your workout?

I figure it only makes sense that having more or less air in your yoga ball has to make a difference to your workout. Which way is gonna to make th most difference when using it as a seat at my desk?|||Why don%26#039;t you just try inflating it to different levels and try it at a different amount each day? Then you can decide for yourself what feels like it makes you use your muscles more.





:)|||The more you inflate it the more difficult it is to balance on. So if you are just starting out you should probably leave it a bit under inflated.