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.

Standard plank

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1. Plant hands directly under shoulders (slightly wider than shoulder width) like you’re about to do a pushup.

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.

Forearm plank

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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.

Knee plank

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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.

Side plank

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This variation engages your obliques (the side muscles of your core) better than a standard plank.

Lie on your side with one leg stacked on top of the another, then prop your body up on your hand or elbow while keeping feet stacked.

You can make the plank more difficult by raising the opposing arm or leg — or both — in the air. You can make it easier by crossing the upper leg in front of your body for additional support.

Single-leg plank

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By removing one point of contact with the ground, this variation increases the demand on your core.

Position your body in a standard plank, then lift one leg toward the ceiling as far as you comfortably can without compromising your back. Keep hips parallel to the floor, then alternate legs.

Medicine-ball plank

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Up the intensity by planting your hands on a medicine ball rather than on the (much firmer, steadier) floor.

Stabilizing your body on an unstable ball adds a balancing component to the move, increasing the demand on your core. Follow the same steps for a standard plank, but instead place your hands or forearms on the ball, directly under the shoulders.

Collapsing your lower back

Instead of compromising your lower back by dipping your butt, engage your core by imagining your belly button pulling in toward your spine. This will help keep your torso flat and, in turn, your spine safe.

If you want to get super technical, have a friend gently place a broomstick or yardstick on your back. The top of the stick should make contact with your head, and the bottom of the stick should rest between your buttocks.

The stick should also make contact right between your shoulder blades for proper alignment.

Reaching your butt to the sky

Planks aren’t supposed to look like Downward Dog.

To really get your core working the way it should in the plank position, keep your back flat enough so your abs feel engaged from top (right below your sternum) to bottom (directly below your belt). Just don’t dip your tush too far toward the floor.

Letting your head drop

While the focus may be on keeping your hips, butt, and back in the proper position, form isn’t just about your core and lower body in this move.

It’s important to think of your head and neck as an extension of your back. Keep your eyes on the floor, letting them rest about a foot in front of your hands, which will help keep your neck in a neutral position.

Forgetting to breathe

It’s human nature to hold your breath when you’re in a strenuous position. But denying yourself oxygen can bring on dizziness and nausea, which are unpleasant at best and dangerous at worst.

Focusing too much on the stopwatch

Quality trumps the quantity of seconds ticking away. When your form begins to suffer, it’s time to call it quits. If your back starts to bow or your shoulders start to sink, take a break.

Thanks to our friends at Lululemon for outfitting our model in the Speed Tight II and Studio Racerback.