For just $79.95 and five minutes a day, you, too, can get abs of steel! Or so the infomercials go. A recent study, though, has shown that fancy hardware is not the best way to firm up your flabby gut. Using EMG equipment, Dr. Peter Francis of the biomechanics lab at San Diego State University measured muscle activity generated during various abdominal exercises, from basic crunches to sit-ups that utilize oft-hawked contraptions.
Francis discovered that the two most efficient ab exercises are your basic bicycle sit-up and the hanging knee raise. Both not only hit the rectus abdominis (the six-pack muscles) but also engage the abdominal obliques. "They're both mechanically difficult and demanding exercises," says Dr. Francis. "What kicks in the obliques is either rotation or the need to stabilize the pelvis." The big loser in the study: the Ab Rocker (as seen on TV!). "It's particularly ineffective," he says.