Health clubs were once devoted to heart-thumping cardio workouts and sweat-making weight lifting. But that's so yesterday. If you want to keep current for 2003, says the American Council on Exercise (ACE), focus on "active relaxation."

The San Diego-based industry group insists the term, which it did not coin, is less of an oxymoron than it seems. Active relaxation includes such practices as tai chi, Pilates, yoga, stretching and various movement classes where the focus is more on the relaxing motion and rhythm of the exercise than on exertion level, says Cedric Bryant, ACE's chief exercise physiologist. The new category is not to be confused, says ACE, with passive relaxation -- the realm of massages, whirlpools, and steam baths. Both produce relaxation, but active relaxation requires some movement to get there.

"In the past, the emphasis was on tough, aggressive workouts and going for the burn," says Bryant, "That's fallen out of favor," as has pushing to improve aerobic capacity or see how strong you can get. Instead, he says, people are seeking gentler forms of exercise as "a distraction to break up the day and manage stress in their lives."

Results of a new study of 1,200 health clubs by the International Health, Racquet & Sportsclub Association (IHRSA), a health club trade group based in Boston, demonstrate the clubs' ability to react to the changing preference: 86 percent of clubs offer yoga, up from 38 percent in 1996. Twenty percent offer tai chi -- an ancient Chinese exercise whose movements originate from the martial arts -- an activity that was tracked for the first time this year. "Pilates has gone from a blip to 40 percent of clubs now offering it," says Bill Howland, IHRSA's director of research.

Active relaxation isn't limited to the yoga mats: Elliptical trainers are its aerobic equivalent, says Bryant, providing you keep the speed setting below 4 and focus instead on the equipment's rhythmic nature. "Elliptical trainers offer a continuous gliding motion, and people often perceive the equipment as not as challenging as the StairMaster," says Bryant. According to IHRSA, there were 4.5 million elliptical trainers in U.S. health clubs in 2001, up from 1.1 million in 1997.

These and other health club changes, says ACE, reflect an aging, more joint-sensitive demographic. Americans over age 55 are the fastest-growing age group among gym members, up more than 266 percent since 1987 -- more than twice the rate for U.S. health club members as a whole, according to IHRSA.

Does the trend spell a necessary decline in Americans' fitness levels? Not according to Bryant. People can get in "terrific shape" through active relaxation, says Bryant, provided they exercise slightly longer to make up for the decrease in intensity. And the trend, he says, has another advantage: "When you find something that's pleasurable and not overly stressful, you're more likely to stick with it long term," he says.

-- Therese Droste