How to Do an Abdominal Crunch

Proper Form, Variations, and Common Mistakes

Verywell / Ben Goldstein

Targets: Abdominals

Level: Beginner

Crunches have been the mainstay of ab workouts for decades. They target the rectus abdominis, the six-pack muscle that runs along the front of the torso. Building this muscle is one part of developing your core muscles for stability and performance. Crunches can be part of a core strength workout or a total body workout.


The rectus abdominis muscle flexes to bring your shoulders towards your hips. As one of the major core muscles, it provides stability for the body. A strong back and abs are the foundation of all your daily movements as well as performance in sports.

Step-by-Step Instructions

  1. Lie down on the floor on your back and bend your knees, placing your hands behind your head or across your chest. Some people find that crossing the arms over the chest helps them avoid pulling on the neck. However, if you find your neck is strained, you can keep one hand cradling the head. If you are putting your hands behind your head, your fingers should gently cradle your head. The idea is to support your neck without taking away from the work of your abs.
  2. Pull your belly button towards your spine in preparation for the movement. 
  3. Slowly contract your abdominals, bringing your shoulder blades about 1 or 2 inches off the floor.
  4. Exhale as you come up and keep your neck straight, chin up. Imagine you're holding a tennis ball under your chin. That's about the angle you want to keep the chin the entire time.
  5. Hold at the top of the movement for a few seconds, breathing continuously.
  6. Slowly lower back down, but don't relax all the way.
  7. Repeat for 15 to 20 repetitions with perfect form for each rep.

Common Mistakes

Doing crunches correctly is harder than it looks. Avoid these errors so they can be as effective as possible.

Pulling on the Neck

This not only strains the neck, but it takes away from working your abs. You want to originate the movement in your abs, not from your head. To keep your neck in proper alignment and not moving, place your fist under your chin.

Crunching Too High

The crunch is a subtle movement, lifting the shoulder blades just a few inches off the floor. Jerking the shoulders up adds momentum and reduces the effectiveness of the exercise. It takes time to build strength in the abs, so it's best to take your time and do the move slowly rather than using momentum to get the body up.

Relaxing Down to the Floor

It's easy to let your shoulders fall to the floor but a more effective approach is to keep the tension on the abs throughout the entire movement. You never want to completely relax the shoulders onto the floor.

Back Arch

In the past, it was recommended to keep your back flat against the floor throughout the entire movement. Now it is believed it is better to keep a neutral spine. That simply means your spine is in the strongest position to support you.

A quick way to find it is to rock the pelvis back and then forward and then allow your pelvis to relax somewhere between those two extremes. If your back arches too much, that may mean your abs need time to build strength. Try propping your feet on a step or platform to give your back some support.

Modifications and Variations

The crunch can be used by all levels of exercisers. Additionally, there are many options available to customize this exercise to fit your individual needs.

Need a Modification?

While crunches are fine, there are plenty of other effective ab exercises. Some of the best exercises for your core are done using your entire body, not just your abs. Options include:

  • Reverse woodchops with the band
  • Side bends with a medicine ball
  • Overhead squats
  • Med ball rotations with static lunges
  • Standing side crunch

It's great to incorporate exercises into your routine that work the abs naturally. For example, compound exercises like squats with an overhead press or pushups with a side plank almost always put quite a bit of emphasis on the core. In addition, the more muscles you work during an exercise, the more functional that exercise is and the more calories you burn.

Up for a Challenge?

To add variation, bring your knees in at the same time you lift your upper body off the floor (full body crunch). To make it more difficult, balance on an exercise ball, or hold a weight at your chest. Here are some more common crunch variations:

  • Bicycle crunch exercise: This ab exercise generally ranks at the top of the list of best ab exercises if done properly.
  • Vertical leg crunch: This version can be a challenge for the lower back if done improperly; make sure you do it right by having a trainer check your form.
  • Long arm crunch: This exercise is another version of a favorite exercise that almost anyone can start doing.
  • Reverse crunch: Get some extra challenge by kicking up the feet with the torso holding steady.
  • Crossover crunch: This exercise is especially good for the obliques.

Safety and Precautions

If you have any back or neck problems, talk to your doctor or physical therapist about whether crunches are appropriate for you. If not done with proper form, they can compress the spine and stress the neck. Avoid crunches after the first trimester of pregnancy, as soon as the belly expands.

Try It Out

Incorporate this move into one of these popular workouts:

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2 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Maquirriain J, Ghisi JP, Kokalj AM. Rectus abdominis muscle strains in tennis players. Br J Sports Med. 2007;41(11):842-8. doi:10.1136/bjsm.2007.036129

  2. Evenson KR, Barakat R, Brown WJ, et al. Guidelines for physical activity during pregnancy: Comparisons from around the world. Am J Lifestyle Med. 2014;8(2):102-121. doi:10.1177/1559827613498204