David Miller

Anders says the movement began with golfers who sought extra help from personal trainers at health clubs to strengthen the abdominal and lower back muscles that drive their swing. The strategy soon caught on with wanna-be bike racers, marathoners, and triathletes. "Mountain bikers need strong legs and joints," says CC Cunningham, 31, a certified athletic trainer in Chicago who works with a handful of clients seeking sports-specific training, "but they also need balance and core strength. And you don't develop those areas as fast as possible just by riding."

Aspiring competitive athletes comprise only a portion of Cunningham's business. She also caters to adventure travelers, a category bound to keep growing given the worldwide explosion of trekking, biking, climbing, and kayaking. "There's nothing more miserable than an adventure vacation you're not in shape for," she says. "I know of people who developed wrist tendonitis after mountain-bike trips, and then couldn't use a keyboard when they got back to work."

Cunningham and Anders suggest seeking a trainer certified through organizations like the American College of Sports Medicine (317-637-9200) or ACE (800-825-3636). Since backgrounds vary from enthusiastic personal trainers hooked on a particular sport to retired athletes (who don't necessarily excel at being private coaches), look for references from happy clients, a personality you can live with, and realistic programs that adapt to your current fitness level. Expect to pay anywhere from $30 to $100 an hour (Cunningham charges $75). Most trainers operate out of clubs, where they can advertise more efficiently, but they also conduct workouts on the trail or at clients' homes.

Is it worth it? Amateur triathlete Mike Mitchell, who's been working with Cunningham for the last six months, now swears by sports-specific training. "I've been a triathlete for four years and have done a couple of dozen races," he says. "I read all the magazines and books, and I did improve. But then I plateaued. Working with CC got me out of my rut." —TERRY MULGANNON