Physique 57, which mixes ballet, Pilates, and isometrics, has fans in Hollywood starlets like Zooey Deschanel, Lisa Rinna, and Parker Posey. But perhaps its biggest celeb fan is Kelly Ripa: "[Physique 57] transformed my body in ways I never thought possible. I'm a short person, but I'm becoming longer and leaner. The class works your glutes, your abs, and your obliques. It's all about building muscle, then stretching it out."
If you can't make it out to LA or NYC for classes, the wildly popular workout now offers at-home fitness DVDs!