Health and fitness: strong ... and lean.

Big, bulky muscles are a dancer's nightmare. You work hard in technique class to lengthen your line, and the last tiring you want are exercises that counteract all your efforts. As some dancers are discovering, new twists on familiar training methods let you build strength but still maintain a long, lean look.

Working with kettlebells has become popular at companies like New York City Ballet and Miami City Ballet. First favored by Russian power lifters, the weighted balls with U-shaped handles have been around for decades. Dancers who work out with kettlebells perform spiraling, three-dimensional movement. "A kettlebell's center of mass is outside of your palm," says Michelle Khai-Cronin, a conditioning specialist who has a BS in exercise science and is Kettlebell Concepts' education director. Exercises with regular weights keep movement to a controlled minimum, but kettlebells encourage it, using momentum to move through space. "In dance we're always playing with momentum," says Khai-Cronin. "With kettlebells you're utilizing your whole body in free movement resistance training." This helps build coordination and timing without increasing muscle mass.

Hydraulic resistance has become more popular too. Exercises that involve stability balls, resistance bands, or medicine balls mimic the feel of working in water, and tend not to build bulk. "Do a grand battement in a pool and memorize how it feels," says Deanna McBrearty, a former New York City Ballet dancer and certified personal trainer. "After that, in the studio your leg will feel a lot lighter." This approach to strength training allows dancers to explore and make up movement, which many prefer. "I gravitate towards exercises that use my own body's resistance, like push-ups, releves, leg raises, and mat work," says McBrearty.

Some dancers still believe in the weight-training-leads-to-bulk myth despite the urgings of company physical therapists who try to dispel it. "I've seen a 90-pound dancer lift 60 pounds on knee extension equipment to build quadriceps strength after an injury and not 'bulk up,'" points out Shaw Bronner, director of physical therapy for Alvin Ailey American Dance Theater.

"Women don't produce the level of testosterone necessary to develop very bulky muscles," says Johanna Leigh Heflin, an education consultant with New York's Harkness Center for Dance Injuries. "The strength training you do as a dancer is not the type you would do if you are a bodybuilder," she continues. "For a dancer, supplemental training three times a week is appropriate for strength gains and then once a week after that to maintain it."

The advantages to weight training extend to injury prevention as well as recovery. "Dancers should engage in resistance and supplemental training to correct muscular imbalances," says Heflin. She notes that the lower back is a common injury site. "A training technique like Pilates goes beyond the superficial muscles and works the deep core muscles, the transverses abdominis," she says. "It's actually strengthening the lower back."

Weight training can also build dancers' performance energy--both aerobically and anaerobically. Working with low resistance and high repetitions remains a classic formula that doesn't increase mass. "Powerlifters aren't looking for endurance," points out Bronner. "They need one powerful burst to lift a heavy dumbbell and then put it down. Think of yourself as a marathon runner versus a sprinter. A marathoner is lean while a sprinter has enormous thighs." Whether resistance is considered low or high depends on which muscle you're targeting. Doing a bicep curl with a 20-pound weight could be considered a heavy load, but the same weight probably won't be a challenge for your quadriceps. When in doubt, always seek out a trainer's advice.

Keep in mind that compared to fat, muscle is very dense. Increase your muscle mass and your metabolism gets an automatic boost. Muscle weighs more than fat so it's possible to build muscle mass and gain weight but appear smaller visually because you've decreased your overall fat percentage.

PTs and trainers who work with dancers urge them to stay focused on what they want to achieve, not on the mirror. According to Heflin, it's easy to avoid bulking up. "Adding supplemental strength training will make you feel better because your body will be developed properly. And, muscle tone looks good onstage!"

Khara Hanlon is an assistant editor at Dance Magazine.