Okay. I would have never thought that this would have much effect but these 2 styles of doing crunches seem to vary alot. Anybody know why? what muscles do each one strengthen? And why the heck when the knees are crooked does the muscle underneath that connects from hip to under of knee seem to be getting a workout also?

See attached photo. Thanks.

Well the top one is obviously harder. Look at that guy he's sweating bullets.

:roflmao:

The one with legs bent will be easier on your back. I think this is why the legs bent method has been pounded into me since grade 5.