The unkindest cut you could give a runner, back when the sport was still new, was to call him (most runners then were male) a "jogger." Jogging was viewed as less serious, less macho and well, slower, than running. The men in shorts who launched America's running boom during the late sixties and early seventies typically ran with fierce determination, striving for faster times and longer distances.

Today the sport is more popular than ever, but runners have changed dramatically. The elitist, "faster-is-better" mentality has been replaced by a kinder, gentler approach with less emphasis on competition and more focus on health. More participants are over 40, a growing number are female and increasing numbers are entering races, joining clubs and getting coaching to help them reach a wide range of goals -- from starting a running program to finishing a marathon.

"Running is becoming a fitness sport rather than a competitive sport," says Amby Burfoot, executive editor of Runner's World magazine, whose circulation has continued to rise since it began in 1966 and jumped 10 percent in the past two years to 505,000. "It used to be that everyone wanted to qualify for the Boston Marathon. Now more people are running for health and fitness, to control their weight and to reduce their stress."

The now-mainstream sport is maturing at the same time as many of its leading proponents. Even Burfoot, who won the 1968 Boston Marathon, admits that at 52 he sometimes…walks!