AS SEEN ON TV Ever wonder how many "field-tested, scientifically proven" ab devices actually work?  Researchers at Occidental College in Los Angeles did.  They measured the amount of stress six devices place on your abs and compared them with the traditional crunch.

The Ab-One - which uses a resistance band - was the only product to elicit a greater muscle stimulus than the crunch, because, the researchers say, it places additional stress on the muscle as you crunch.  You can produce the same result by doing a traditional crunch while holding a medicine ball or weight plate.