High intensity moves are the best way to set fat on fire—anytime you spike your heart rate high, you’re boosting your metabolism to burn more calories.

Mountain climbers may be classic, but it’s really squat jacks that jack up your metabolism, says New York-based trainer Chris Ryan, C.S.C.S. “Both moves focus on your glutes, and whenever you engage your butt, odds are it will be a metabolically-challenging move since this is our biggest muscle,” he explains.

But mountain climbers can be a tougher exercise to maintain ace form—it can be hard holding plank position if your wrists are tight or you have limited mobility in your glutes. Squat jacks, on the other hand, help open up your hips and burn your booty, legs, and core more, says Ryan.

That means dropping low will not only rev your metabolism to burn fat, but it’ll also build a great booty.

Here's what you need to know to give both of these metabolism-boosting moves a try:

Mountain Climbers: Assume a pushup position with your arms straight and your body in a straight line from your head to your ankles, core and glutes engaged. Without changing the arch in your lower back, raise your right knee toward your chest. Pause, return to the starting position and repeat with your left leg. That’s one rep.

Squat Jacks: With your feet hip-width apart, lower your body until your knees are bent to almost 90 degrees. Explosively jump your legs outward, and then immediately jump to bring them back to starting position. That's one rep.