Athletes need to challenge their cores in crazy ways to stay in fighting shape. To find out just how insane these pros are, we sought out the single most difficult ab move on the planet. And (eureka!) we found it: the Hanging Windshield Wiper, courtesy of Bo Sandoval, an Olympic strength and conditioning coordinator.

How it's done Hang from a pull-up bar with your arms shoulder-width apart, palms facing away from you. Keeping your arms straight, raise your body so your hips, back, and shoulders are as parallel to the floor as possible. Raise your legs straight up so you're in pike position (A).

If that's not difficult enough, rotate your legs down to the right (B), bring them back to centre, and then lower them to the left (C). Yow.

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"We have a couple of female wrestlers and women's volleyball players who can do it," Sandoval says.

Full disclosure: As for the ripped gal in our photo? Not even she could handle it! We used Photoshop magic to erase the dude holding her up.

Disclaimer: WH is not responsible for hernias. Bonne chance!