Grab a pair of dumbbells of your choosing and hold them at your sides, though you can perform this move as a bodyweight exercise like Arias does here. Place the toes of your right foot on a bench, box, stair, or chair.
Make sure your left foot is out far enough so that when you lower your hips, your knee stays over your ankle.
Bend your left knee, squeeze your right glute, and lower your pelvis toward the ground. Your back knee should be hovering over the ground.
Press your left heel into the ground to straighten your left knee, so that you come back to standing. This completes one rep.
Continue for 30 seconds, then do an additional 30 seconds on the other side.