If there’s one exercise we all love to hate and hate to love, it’s this one. A plank is a simple, effective bodyweight exercise that requires no equipment and can be performed just about anywhere (well, use your judgment). Holding your body (light as a feather) stiff as a board develops strength primarily in your core — the muscles that connect your upper body and lower body — as well as your shoulders, arms, and glutes.

Find out how to perfect your planking (no, not that kind) and fix some of the most common plank mistakes with this guide.

1. Plant hands directly under shoulders (slightly wider than shoulder width) like you’re about to do a push-up.
2. Ground toes into the floor and squeeze glutes to stabilize your body. Your legs should be working, too — be careful not to lock or hyperextend your knees.
3. Neutralize your neck and spine by looking at a spot on the floor about a foot beyond your hands. Your head should be in line with your back.
4. Hold the position for 20 seconds. As you get more comfortable with the move, hold your plank for as long as possible without compromising your form or breath.

This variation, one of the most common ways to perform a plank, is slightly easier than holding your body up with just your hands.

Place forearms on the floor with elbows aligned below shoulders and arms parallel to your body at about shoulder width. If flat palms bother your wrists, clasp your hands together.

Note: Any of the following plank variations can be performed with straight arms or in a forearm position.

This plank is noticeably easier to hold than the traditional straight-arm plank, which makes it great for beginners because it allows them to concentrate on form.

Resting your knees on the ground puts less stress on your lower back. Rest your knees on a rolled-up mat or towel if they feel uncomfortable on the floor.