Johnny G., the inventor of Spinning, is at it again, rolling out a new upper-body workout called Kranking, which uses hand-powered pedals to boost your heart rate and strengthen your chest, back, and arms.

“It works through high-repetition rotations and adjustable resistance – the same way a stationary bike firms your butt and legs,” says G. (a.k.a. Jonathan Goldberg). Experts suggest alternating sessions with a regular Spinning bike for the best results.

“Kranking burns fat and works muscles differently than most other machines, so it’s the ultimate cure for flabby arms,” says Los Angeles personal trainer Gunnar Peterson, who has been testing the machine.

“But your arms are a smaller muscle group, so pedaling with them won’t burn as many calories.” The machines are currently available in only a handful of gyms, such as Equinox Fitness Clubs in Pasadena, California, and the Sports Club/LA in Boston.

Bottom Line on Kranking Workout: One tester says that arms felt like noodles after one 30-minute class at New York City’s Reebok Sports Club/NY. [source: Allure]