I don't know if they work. And you don't have a bad back by chance do you? My aunt had one but she has metal rods in her back for scholeosis (sp?) so she didn't use it long because she didn't want to hurt her back bad. Mama has one, she uses it sometimes (maybe regularly, i'm not home too often

). I have used it...didn't seem like it did too much besides being a little painful on my sides

I am also good at it though and you apparently lose more weight if you're bad because you have to work harder to keep it up (makes sense).
So, my advice...get one if you want because it is an easy way to shed a lb or two at least and if it doesn't work for more than that, you're not out THAT much money :shrug: I think it should definitely help tone abs either way though because you have to tighten your stomach muscles