"You are how you move," says Tracy Anderson, crossing her sinewy legs. "You don't want to be strong and clumsy, like a bison; you want to be strong and agile, like a jaguar." If you haven't heard of the 38-year-old, five-foot-tall trainer, it's likely because she's built her rep sculpting the bodies of A-list ladies—including Madonna, Jennifer Lopez, and Gwyneth Paltrow (who even became a business partner)—not lads, but that's changing. She has quietly added male clients like Robert Downey Jr. and Matthew McConaughey to her roster and is now targeting the rest of mankind.

This month, she'll launch a treadmill-like contraption with a built-in obstacle course called the Men's High-Intensity Machine at two of her four gyms (in California and New York), and she'll follow up in early 2014 with a manly fitness DVD. "My clients' husbands have seen their wives transform," she says. "They want to try the workouts too." Her new business proposition capitalizes on the oft-ignored fact that men want to work out like the fairer sex.

To a retrograde gym rat, Anderson's made-for-guys routines look girly—you won't lift a free weight over 10 pounds and many of the motions appear negligible. However, the high reps will leave you hurting. In a typical session, you might throw punches with light dumbbells before lifting that same weight in a floor-to-ceiling row, as if yank-starting a lawn mower. (Her masculine workouts pay special attention to the pecs, biceps, triceps, and delts.) Next, you're doing push-ups with oblique crunches. Six or so floor exercises, and it's on to cardio, grabbing overhead elastic bands and incorporating them into jumps and squats. Every move engages a multitude of muscles, especially around the core. The result: none of the "compartmentalized" bulk seen on dudes waddling from weight room to smoothie bar.

What's the logic behind the Tracy Anderson Method (TAM)? "The body has more than 600 muscles," she says. "Most fitness regimens only tap into 200. I get to 400." TAM is designed to confuse muscles, making them—and your heart and lungs—work harder. Moves are contrived to tire out the big groups so that lesser-known "accessory muscles" (i.e., the ones deep in your doughy middle or beneath fleshy arms) activate. In other words, wear down the starting lineup so your benchwarmers can show the crowd what they're capable of.

"It shreds you," says Kevin Daniels, 27, a TAM trainer and former professional dancer. "Anyone can hit the primary muscles. But tightening the secondary ones to maintain definition long-term while building cardio endurance—that's what men need."

Not all fitness pros, however, are convinced that Anderson's technique is the right way to exercise. "It's not as supported by science as other workouts," says Grace DeSimone, editor of American College of Sports Medicine's Resources for the Group Exercise Instructor and a certified trainer. She's also worried that the program focuses more on muscle endurance than on strength: "Higher-weight, lower-rep sessions are needed to address bone density and metabolic concerns." But, she adds, "it's going to wake guys up." To become the jaguar, you may first have to feel like a bison.

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Anderson's 3 Secrets to Healthy Eating

• Eat a diet rich in lean proteins, including mostly those that contain all nine essential amino acids. Grilled meat, fish, and poultry are your best bets.

• Before a workout, consume both carbohydrates and protein. The former provides the energy needed to make it through a high-intensity session; the latter helps maintain muscles.

• Drink up. If you have a hard time downing a lot of water, anything liquid, like a shake—especially one made with fruits and vegetables—will hydrate you.

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Made for a Woman, Strong Enough for a Man:
The Evolution of Crossover Workouts

1970s: Ballet
The founding of the all-male troupe Les Ballets Trockadero de Monte Carlo and the prevalence of athletes doing pliés reduce the stigma of men in tights.

1989: Step Aerobics
Gin Miller invents the Reebok Step, taking traditional aerobics classes out of their bored-housewife milieu.

Late 1990s: Yoga
The rise of athletic styles, like Ashtanga and Bikram, helps it shed its hippie-dippie stereotype.

Early 2000s: Pilates
More than 70 years after boxer and gymnast Joseph Pilates created his eponymous method, average Joes realize it builds core strength and sculpts definition.

2004: DVDs
Fitness videos—the progeny of Jane Fonda—grow a pair with the release of Tony Horton's P90X.

2009: Spinning
Guys reclaim their place in the saddle, re-embracing this once-unisex workout that was co-opted by women through the rise of studios like SoulCycle and Flywheel.

2010: Barre Classes
Pure Barre, Bar Method, and Mind Body Barre (among others) begin offering sessions tailored to guys (with names like Pure Man and Man Up).