How to Do a Reverse Crunch

Proper Form, Variations, and Common Mistakes

Verywell / Ben Goldstein

Targets: Abdominals

Level: Intermediate

The reverse crunch is an intermediate level variation of the popular abdominal crunch exercise. Your upper body remains on the mat as you contract your abs to draw your legs towards your chest. It exercises the full length of the rectus abdominis muscle (the six-pack muscle), getting to the deep lower abs. This bodyweight exercise is easy to add to any abdominal or core workout or use as part of a total body workout.


You might prefer the reverse crunch if you have difficulty with neck discomfort in the traditional crunch or situp. This exercise will activate your major abdominal muscles, including the external obliques on the sides of the abdomen. It is good for developing an appealing stomach musculature as well as strong and functional abs. A strong core is a basis for improving your sports performance and maintaining balance, stability, and good posture in daily life. Strengthening the abdominal muscles will prepare you not only for vigorous sporting activity but also for those active tasks around the home, like gardening, where bending and twisting and reaching are paramount. It is good to include a variety of ab exercises in your routine so your core muscles are challenged in slightly different ways.

Step-by-Step Instructions

Lay face up on the mat with your arms at your sides. They can be closer to your body or extended comfortably to use for balance.

  1. Bend your legs at the knee and brace your abs to slowly raise your legs so the knees are directly over your hips and your lower legs are parallel to the floor (bent 90 degrees). This is the starting position. Brace the abdominal muscles and hold a neutral spine position with a slight natural curve in the lower back (lumbar) region yet with the back firmly against the floor.
  2. Exhale as you contract the abs to curl your hips and knees toward your chest, with only your hips coming off the mat as you curl. Your knees should remain at the same angle throughout this upward phase. Your head should be kept straight and the neck and shoulders should remain relaxed and on the mat. Hold when you cannot curl without your back coming off the mat.
  3. Inhale and slowly return to the starting position with your hips back on the mat and your knees over your hips, still bent 90 degrees.
  4. Try 10 repetitions for three sets starting out and increase it as you get stronger.

Common Mistakes

Avoid these errors so you get the most out of this exercise while avoiding strain and possible injury.

Using Momentum

It is tempting to do the reverse crunch fast and use momentum to curl you up rather than the contraction of your abs. Avoid this by doing it slowly and with control. If you are unable to draw your legs towards your chest without using momentum, you need further ab strengthening with other ab exercises.

Rolling Too Far

Only your tailbone and hips should be raised from the mat in the upward phase. Stop when you lose contact with more of your back. If you are doing the reverse crunch slowly you are less likely to go too far than when you are using momentum and doing it in a quicker motion.

Unrolling Too Far

On the downward return, be sure that you don't roll too far and the knees end up in front of the hips. If you are going slowly you should be able to stop, but if you lack the strength to go slow you might find yourself letting your body drop instead. This is a sign that you need more ab strengthening before being able to do the reverse crunch with good form.

Modifications and Variations

There are many ways to do crunches. Beginners can change to a format they can do with good form as they develop strength. As you progress, you can add difficulty.

Need a Modification?

If you find you don't have the ab strength to roll up without momentum or control the return to the starting position, try a shorter range of motion. In the upward phase, go only as far as you can with control. At first, this may be just a tiny motion that doesn't bring your tailbone up off the floor.

You can also build the strength you need by doing toe taps. From the starting position, lower one leg with pointed toe until it taps the ground. Return that leg to the starting position and then repeat with the other leg. Keep your lower back, hips, and tailbone on the mat throughout this exercise. Aim for 15 to 20 toe taps per side.

Up for a Challenge?

A combined crunch or full crunch integrates both shoulder and leg/hip movement in one exercise. It can be done from the starting position of your legs in the air bent at 90 degrees or with your knees bent and feet flat on the ground. This is a very powerful advanced exercise working the rectus abdominis and the external obliques, the muscles at the sides of the abdominal area. When you can do three sets of 15 combined crunches you know your abs (and hip flexors) are in good shape.

Safety and Precautions

If you have any back or neck injuries or conditions, talk to your doctor or physical therapist about whether this exercise is appropriate for you. You can expect to feel stress and even burning in your abdominal muscles during this exercise, but not any sharp pain. If you experience any pain in your stomach, back, or neck, slowly come back to a comfortable position and end the exercise. This exercise should be avoided in pregnancy.

Try It Out

Incorporate this move and similar ones into one of these popular workouts:

5 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.
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  3. Granacher U, Schellbach J, Klein K, Prieske O, Baeyens JP, Muehlbauer T. Effects of core strength training using stable versus unstable surfaces on physical fitness in adolescents: a randomized controlled trialBMC Sports Sci Med Rehabil. 2014;6(1):40. doi:10.1186/2052-1847-6-40

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By Paul Rogers
Paul Rogers is a personal trainer with experience in a wide range of sports, including track, triathlon, marathon, hockey, tennis, and baseball.