It's a silly question but since i don't have an exercise ball and scared i can't get one that will stay inflated without spending a ton of money i'm just not buying one. So for the xtrain cbs and bi and tris what can i sub with?
I have a cheap one that won't stay inflated. I would love some recommendations please. The Xtrain series has some, i wonder if those stay inflated or if someone always pumps them up before use,thanx:)