Stronger abs without a single crunch? Yes, please. Here's how to do a plank the right—and why they're so good for you.

The plank is the most accessible exercise that gives the best outcome for building core strength. It's one of the simplest yet most challenging movements, as it engages many different muscular groups ...

YOU PROBABLY THINK you know how to do a plank. The ab training staple is relatively simple, after all—boiled down to the basics, all you need to do is get down on the ground and hold in place.