Everything You Knew About Good Abs May Be Wrong

It used to be that the only time someone told you to suck in your gut was when the family had lined up for a photo at the Grand Canyon.

Today, the advice to draw your navel to your spine is ubiquitous and has little to do with vanity. Drawing in (as the move is called) is supposed to engage a deep abdominal muscle called the transverse abdominus. (The technique involves inwardly pulling in, distinguishing it from the more general advice to contract the abdominals.)

Fire the transverse abdominus, the thinking goes, and the torso temporarily acts like a muscular corset, protecting the lower back. Practice firing that muscle enough, and over time not only will you get a strong midsection, but the transverse abdominus will eventually fire on its own.

Physical therapists instruct back-pain patients to draw in during sessions and as all-purpose advice before lifting groceries. Personal trainers instruct clients to perform the move during mat exercises and on stability balls; some even say you should be drawn in while running or cycling. And Pilates relies on some form of drawing in, although it also addresses a whole range of muscles related to core strength.

But new questions are being raised about whether drawing in is an appropriate technique for all kinds of exercisers. Critics, including personal trainers and specialists in the spine and biomechanics, are now saying that drawing in may not make sense while, say, lifting weights or performing a crunch or running a race. In fact, some say, drawing in may even be counterproductive.

"If you hollow in, you bring the muscles closer to the spine, and you reduce the stability of the spine," said Stuart McGill, a professor of spine biomechanics in the department of kinesiology at the University of Waterloo in Ontario. Try rising from a chair with a hollowed out stomach; not only are you "weak," he said, but "it's very difficult." ...

Some trainers who once thought that drawing in was the key to protecting their lower back and building a strong midsection are now having second thoughts. Vern Gambetta, the author of "Athletic Development: The Art & Science of Functional Sports Conditioning," now thinks the move is difficult to teach and too unnatural for athletes to maintain while being at their competitive best.

"In most sporting activities, things happen too fast to consciously think about contracting a specific muscle," Mr. Gambetta said.

He and others have also seen that no matter how many times people hollow out their stomachs, firing the transverse abdominus rarely becomes second nature.

"I don't know of a study that shows that drawing in becomes a subconscious reflex," said Shirley Sahrmann, a professor of physical therapy at the Washington University School of Medicine in St. Louis.

•	Everything You Knew About Good Abs May Be Wrong The New York Times, Thursday, Feb. 22, 2007 Byline: Paul Scott