Loosen up and strengthen your core with this one-of-a-kind device

Origin: Gyrotonic was invented by Juliu Horvath, an eccentric Hungarian ballet dancer. Classes began as far back as the eighties, but in the past five years the number of trainers has quadrupled, and there are more than 1,200 studios worldwide.
Who's Doing It: Björk, Madonna
The Workout: "The idea is to work in spirals," says Lisa Marie Goodwin, a Marina del Ray–based instructor. Her words might lead one to believe that Gyrotonic, influenced by yoga, gymnastics, and swimming, could be a tad out there. And that's before you see the, uh, apparatus. Gyrotonic practitioners strap into a spring-tensioned wood-and-steel machine, which allows them to do more than 1,000 different exercises and stretches while lying prone, sitting, standing, or hanging. Integrated with weights and specific breathing patterns, these routines are done with abdominal muscles engaged and wrist, shoulder, hip, and ankle joints supported. Goodwin calls this "stability in motion." In layman's terms, that means you will likely stretch more deeply then ever before but without risk of injury. And you really will move in spirals—the machine's wheels and pulleys encourage circular movement.
They Say: You'll enjoy increased range of motion, improved balance, and better coordination. The evidence? Gyrotonic machines are used in an increasing number of physical-therapy facilities.
I Say: My leg, arm, abdominal, and back muscles were stretched in ways I'd never felt—or thought possible. My abs burned, my tight hips opened, and my lower back relaxed. Afterwards, I was loose and calm, but I couldn't help imagining a dominatrix putting this contraption to good use.
Where to Find It: gyrotonic.com; private classes, $75; group classes, $25