The plank has become an easy, post-workout prescription – usually performed by guys who are more concerned with setting the Guinness World Record for time, regardless of how sloppy their form gets. Which is sad, because who properly executed, the plank is the end-all for full-body stability and better posture. Also, it’ll help you chisel out a great set of abs. Here, we outline how to perform the perfect plank, then offer four variations to take it up a notch. Think you can handle it?