Full levels of blissed-out zen isn’t the only thing you’re bound to experience after a hard AF yoga flow. You’ll also wake up your obliques, glutes, and hamstrings for a full-scale yoga burn that leaves you with that flexed-so-good feeling as soon as you step off the mat. Plus, you’ll fire up your abs for a stronger core — and there are plenty of reasons to do that, none of which include the usual “I want to look good in a bikini” response. (Though there’s nothing wrong with that, so long as you know how badass you look regardless.)

Moves like planks and warrior poses are major core strengtheners commonly found throughout yoga practices, and they boost your balance, breathing abilities, and strength. Plus, they help you strongly get through everyday movements, like walking up and down stairs or lifting boxes and suitcases overhead.  (Related: Vinyasa Yoga for a Stronger Core).

All of that provides more than enough reasons to try this yoga class, led by Grokker’s Julie Montagu. You can also check out Grokker’s site for Julie’s complete 21-day program to learn how feeding your body with nutrient-dense food — and strengthening it through stretching, breathing, lifting, and opening—can change your life.

How to do it: Get into plank position with a Swiss ball beneath your hips and feet hovering above the ground. With legs extended and held apart in a V-shape, engage your butt and hamstrings as you raise your legs straight up. With control, lower your legs back to starting position (no touching the ground!) to complete one rep.