For Pat Aronstein, it was love at first leap.
From the moment the Johns Hopkins nurse stepped into her first class 15 years ago, she was hooked. The camaraderie, the cardiovascular benefits and the music kept her going to class several times a week -- week after week.
But as the years went by and the rigorous jumping and hopping took their toll on her body, Ms. Aronstein's affection for aerobic dance waned. In the past few years, the 35-year-old has been moving away from high-impact aerobics to kinder-and-gentler activities.
"I was starting to get a lot of knee and foot pain from aerobic dance," explained Ms. Aronstein, who now takes part in low-impact "step" aerobics classes (in which participants step up and down on height-adjustable benches to music) at the Downtown Athletic Club. "Step seems to be a lot easier on my joints, and it's not boring at all."
Ms. Aronstein is far from alone. As baby boomers reach middle age, they're seeking new forms of exercise that will cause less wear and tear on aging joints and muscles -- as well as hold their attention.
"There's been a real maturing and mellowing of the fitness boom," said Dr. Kenneth Cooper, fitness guru and director of the Aerobics Center in Dallas. He points to growth in low-impact sports -- exercise walking, step aerobics, swimming or biking -- as well as newer, trendier activities such as roller blading.
Author of "The New Aerobics," Dr. Cooper, in part, attributes changes in attitudes toward workouts to recent studies indicating that people can improve their health by exercising for just 30 minutes three times a week -- rather than knocking themselves out with longer, more frequent workouts. And, he says, the activity doesn't have to be intense to be beneficial: A brisk walk will do.
Across the board, fitness aficionados are taking these lessons to heart. Running, once one of the hottest fitness activities, has lost some of its appeal. The number of runners dropped to 23.8 million in 1990 from 26.3 million in 1985, according to a study conducted by the National Sporting Goods Association (NSGA) in Mount Prospect, Ill.
On the other hand, with 71.4 million participants, exercise walking now holds the lead as the most popular fitness activity in the United States.
"I think peoples' legs and knees were getting worn out," explained Larry Weindruch, an NSGA spokesman. "You have lots of people in their 40s and 50s who don't want to run anymore. Also, you have other people who are just starting to exercise late in life, and they're starting with walking, instead of running."
Carol Stewart is a devoted walker. After attempting unsuccessfully to stick to a jogging routine, Ms. Stewart, a middle school teacher who lives in Columbia, started striding for exercise five years ago. She now walks for 45 minutes at least three times a week.
"Walking is easier on the body; it's not as strenuous as running," said Ms Stewart, 36. "I can do deep breathing while I walk, which I enjoy, and I couldn't when I was running."
The new emphasis on injury-free exercise may also be responsible for the surge in popularity of bicycle riding, said Fred Warwick, assistant manager of Mueller Bike Shop on Loch Raven Boulevard.
The number of people biking regularly in the United States increased to 55.2 million in 1990 -- a jump of 9 percent from 1985.
"The bike is taking the impact from the ground, so you're not beating yourself up while you're riding. You can also go farther distances than when you're jogging for the same amount of time and energy," he said.
But even within health clubs, alternative ways of staying fit are being explored by baby boomers.
Several clubs now offer "personal trainer" services to members who hate facing the weight-lifting machines on their own.
"People tend to feel that if they have an appointment, they have to work out," explained Jim Kasoff, executive director of the Physical Performance Institute in Owings Mills. "It makes them feel guilty if they miss it. Besides, it's getting pampered, and that's kind of a lure."
Paulette Hill knows what he means.
After trying unsuccessfully to lose weight through exercise for many months, Ms. Hill, a hairstylist who lives in Bolton Hill, began working out last January with a fitness specialist at the Physical Performance Institute. Her twice-weekly sessions with Dudley Redding, combined with diet and other exercise, have resulted in a 12 to 15 pound weight loss.
Although she concedes that at a typical cost of about $50 an hour, a personal trainer is a luxury, she says it's money well spent. "I'd gotten to a point where I couldn't do the work on my own. Normally I'd go out to dinner or go shopping and spend that money anyway."
But there are other changes afoot in fitness classes and health clubs, says Diane Szulimowski, fitness director at Bare Hills Athletic Club. More men are appearing in aerobics classes -- and more women are appearing in weight rooms.
In part, Ms. Szulimowski says, that's because the low-impact "step" aerobics classes "get away from the 'dancey' moves that men seem to feel uncomfortable with."
The past few years have seen more women lifting weights -- traditionally a male activity. "There's a lot of crossover," said Bill Camp, a fitness specialist at the Downtown Athletic Club.
This gender crossover in workouts may stem from a philosophy of cross-training, or incorporating a number of different activities into your exercise routine, that's now being advocated by fitness experts. "A variety of activities really allows you to get the maximum benefit from exercise," said Ms. Weller.
In a coming book, "The Strength Connection," Dr. Cooper recommends joggers, walkers and cyclists add at least 20 minutes of strength training two times a week to their exercise routines.
Moreover, as more women train with weights, others may "realize that they're not going to get huge muscles doing resistance work," said Ms. Szulimowski. "They see that women who do it have strong, well-defined muscles, but they don't look like Hulk Hogan."
However they choose to get their exercise, it seems people will continue to make fitness a part of their lives. "The baby boomers set the trends, and we're all getting older now and a little more nervous that we're closer to disease," said Ms. Weller. "So we'll do what we can to prevent it."
Sneaking up on exercise
Even if you've chosen activities that are both low-impact and fun -- such as biking or walking -- it still can be hard to stick with an exercise program. Who hasn't sworn to work out three times a week for the rest of his life -- and then stopped after a couple of months?
It's human nature to fail to meet even well-intentioned goals. But there are ways to improve your chances of staying healthy and fit.
* Exercise with a partner. You'll feel worse breaking a work-out date if your friend is supposed to be there, too. Besides, getting fit is more fun with company.
* Add activity. Take evening walks instead of sitting in front of the TV set. Climb stairs instead of taking the elevator. "Anything that makes you move is going to benefit you," said Diane Szulimowski, fitness director at Bare Hills Athletic Club.
* Vary your exercise routine. Play tennis one day, swim the next, bicycle around your neighborhood the third. Your body will appreciate the changes and you'll be less bored than if you worked out on the same weight machines every day.