Just wanted to add my two cents of info regarding ab wheels.

I love the ab wheel and actually made one myself out of hardware store parts
years ago (for
more than what one costs now at Big5). BUT...

I tore a muscle in my lower abs (VERY PAINFUL) by using the ab wheel when I had
let myself
get out of shape. So, I think it's great as an advanced ab workout once you've
already got
some decent ab strength, but you must be very careful to build up even to the
knee roll out
position (much less the standing one).

I didn't notice the tear when it first happened and after a couple of sleepless
nights of
wondering what this mysterious pain was, I ended up being referred to the
emergency room
for the intense lower quadrant pain because it's one of the prime symptoms of
apendicitis!

Just something to be aware of, that I wouldn't have known if it didn't happen to
me.

Best,
Andrew