From Details: "Why the ass is the new abs"

This is a movement I can believe in:)

Glutes—once the province of spandex-clad women clenching in the aerobics studio or lunging along to their VHS copies of Buns of Steel—are switching sides. Whether it's a flabby ass in need of firming or a flat one that could use some inflation, the backside is the newest trend in men's fitness.

"Beautiful Booty is a class that was designed for women, but now we're seeing more and more men sign up," says Stephanie Vitorino of an Equinox in Woodland Hills, California, the creator of the VBody DVD series. "The look that men were previously gravitating toward—what I call the light-bulb look, with big arms and a huge chest that tapers down to skinny legs—is no longer attractive," Vitorino says. "Men want to be more balanced."

Like defined abs and bulked-up calves, flattering glutes can be elusive. "Genetics are genetics—if you're predisposed to having a flat ass, it's going to be more difficult to meet your goal, but it's not impossible," Kirsch says. "Guys, for the most part, can be prone to building muscle, and they can really get their asses jacked."

"The bottom line," says Vitorino, "is that men are beginning to realize their bottom line is important."

--Details magazine