As exercises go, the plank is an oldie-but-goodie…—and (deceptively) simple.

The plank is a great way to strengthen everything from your glutes to your core to your upper body, and also helps to stabilize your lower back——but only if you do it with correct form.

Here’s how to do a proper plank and mistakes plankers often make, along with several plank variations.

Keeping It Basic: How to Do a Standard Plank

You could argue that a “standard” plank is done with only one'’s palms on the ground. But we'’ll go with a forearm plank, which is easier on the wrists, as our standard version.

1. Using a yoga or exercise mat, get onto your hands and knees. Then position your forearms on the ground, elbows directly under shoulders. You can either place your palms on the ground or keep your hands in fists
2. Stretch your legs out behind you. Then get up onto your toes, keeping your body in a straight line from head to toes. Keep your hips level and look at the space between your hands.
3. Engage your core by pulling your navel up and keeping your shoulder blades back and together, towards your midline. Keep your weight evenly distributed from bottom to top and side to side. Don’t forget to breathe.
4. Lower your body back to the ground once you can no longer hold proper form. Eventually, you’ll want to be able to hold the plank position for a full minute.

Plank Mistakes to Watch For

As with any exercise, poor plank form will not only reduce effectiveness but also increase the risk of injury. Here is what to avoid:

• Moving your hips up or down. Keep them in line between your knees and shoulders.
• Arching your back. Concentrate on pushing your shoulder blades towards one another, which will automatically keep your spine aligned properly.
• Letting your head drop or rise. Keep your neck in a neutral position.

Plank Variations

Here are ways to make a plank either easier or more challenging.

To Make Planks Easier

• Keep your knees on the mat.
• Do a reverse plank by sitting down; then lean back, place your hands and forearms on the ground by your sides, and lift your hips.
• Do planks against a wall so your legs can absorb more of your weight.

To Make Planks More Challenging

• Do a high plank by placing your palms on the ground and holding your arms straight.
• Do a high plank on a medicine or BOSU ball.
• Raise an arm, a leg or one of both.
• Do a side plank: Lie on your side, legs together and extended, then pop up onto a hand or elbow; excellent for working your obliques (side muscles).