Whether you’re a gym buff or not, you’re probably familiar with the plank—that essential core exercise that every trainer and athlete swears by. But if you're like me, you don't “waste” much time doing them. And that's a mistake. Because while it may look simple, the plank is brutally effective. Just 90 seconds of planking will remind you, this isn't so easy.

But it sounds almost too good to be true, right? Strengthen your core, build endurance and sculpt your abs while barely moving a muscle. But the plank does just that. It's the ultimate kick-gut move. In fact, researchers at the Biomechanics Lab at San Diego State University recently found the plank works your core and abdominals more effectively than traditional crunches and, better still, won't wreck your back, either.

A plank also engages your shoulders, upper back and butt along with several muscles in your arms and legs. Put another way, just about every muscle group in your body gets toned and tightened. It's also the perfect exercise to do at home because it takes next to no room, requires no equipment and can literally be done in one minute.

According to Tom Holland, exercise physiologist and author of the upcoming Micro-Workout Plan, the average American spends 56 hours per week sitting—maybe more now—which slowly weakens the core. By adding a daily plank to your routine (I'm doing mine as soon as I get out of bed), you'll start noticing your posture improve and your stomach flatten. In fact, the results are so noticeable, I'm going to add an evening plank to my day. After all, we've all got a minute to spare, don't we?

The key is mastering the correct form of this classic bodyweight exercise and then sticking with it. Set an alarm reminder on your phone until you get into the habit of a daily plank. In a few weeks, you'll see noticeable visible improvements in your muscle tone, core strength and waistline.