I use it mainly for crunches and as a replacement for an incline bench. (I sit on something long and flat and lean back on it for incline bench press and lean forward on it for YTWLs.) I also use it to raise my feet when doing horizontal pullups -- the only piece of furniture I have that's sturdy enough to hold my weight to get under is a bunk bed, so I hang on to the top bunk and put the stability ball on the bottom with my feet on it.