It may not challenge your legs, but it does work your arms, shoulders, chest, back and core. "It's designed for people who want to tone their upper body without jumping from weight machine to weight machine," says Washington.

While I don't see Kranking becoming as huge as the group cycling craze, it's certainly a beneficial way to cross-train. If you're looking to shape those arms, I recommend integrating the class into your cardio routine.

Where you can try it: Reebok Sports Club/NY in New York City, The Sports Club/LA in Boston, Club One Fitness in Northern California and Frog's Fitness in Southern California. Coming soon to additional gyms, including Crunch in Miami and New York City. For more information, go to krankcycle.com.