Want a better-looking belly? Look to The Hundred, a classic Pilates move (and part of this 7-move bikini-body workout) that really works. Demonstrated by our very own fitness expert Kristin McGee, this tried-and-true move is a sure-fire way to manage an unruly midsection. It hits the abs super hard, leaving your tummy firmer and flatter, in record time. And believe us, you are going to feel it’s effects now…and later.

Here’s how to do it: Lie on your back and lift your legs 45 degrees off of the floor. Squeeze your abs, lift your head and shoulders off the ground and pump your arms 100 times.

Trainer Tip: Not feeling challenged enough? No worries. Try lowering your legs closer to the ground. If the original move is too tough, though, simply move your legs into a tabletop position.

Try this move: The Hundred