Stronger abs without a single crunch? Sign us up.

By Kimberly Dawn Neumann

Meet the sit-up’s smarter sibling. Less than 10 minutes of planking a few times a week flattens abdominals more effectively than a thousand crunches can, says Geralyn Coopersmith, the global director of performance and fitness training for Nike. It’s also a test of muscle control. Once you’re in a plank, you shouldn’t shift an inch. The plank is the key to both a whittled middle and a pain-free back. That’s because “strong abs keep your spine supported,” says Coopersmith. “Think of it as midsection multitasking.”plank graphic 

Photograph by Henry Leutwyler