When I heard the record for a woman holding an abdominal plank was measured in hours and not minutes (a whopping 4 hours 19 minutes and 55 seconds), I honestly couldn't believe it. I get the full-body ...

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.