Every five years or so a new fitness craze sweeps through the culture. Television news anchors blather on about the latest, greatest exercise programs. Newspapers and magazines publish features in their Sunday sections, filled with pictures of glistening, glowing, glamorous celebrities hard at work on

Which type of exercise is right for me? Is lifting weights going to give me the best result? Maybe I should concentrate on running - that will really help to strengthen my heart. What about yoga - everyone says yoga is good for flexibility. All of us, at one point or another, have had these conversations

Back in the day, there were no personal trainers. If you needed to learn how to exercise, you got a subscription to one of a few well-known "muscle magazines" and read several issues from cover to cover. Then you joined a "Y" and began to discreetly observe what was going in the weight room, trying to