Crunches - How To

Crunches (How To, Muscles Worked, Benefits)

Crunches are one of the most popular core exercises for everyone from athletes to total beginners who are brand new to working out.


Because, crunches are easy to learn and easy to do, but are still very effective at working the abdominals and building a strong core.

In this article, I’m going to show you how to do crunches, what muscles they work and a few variations and substitutions that you can do in place of crunches.

How To Do Crunches

Equipment Needed

  • None

How To

Crunches with Feet on Floor
  • Lay flat on your back with your knees bent to 90 degrees, feet off the ground
  • Place your hands behind to head and keep your chin off your chest throughout the entire movement
  • Lift your shoulder blades off of the ground approximately 3 to 5 inches
  • Slowly return to the starting position and immediately repeat the exercise until all reps are completed

Coaching Points

Do not pull on the back of the head. The hands behind your head should only be there to support the head, not pull on it. Keeping your chin up and away from your chest will help in preventing this.

Focus on the squeeze of the contraction at the top of the rep. It’s easy to mindlessly rep through crunches without getting much benefit out of them. Focus on each rep.

By not crossing your feet while they are in the air, you force the groin to remain active and work during the reps which can be a small added benefit.

How Many Reps?

I typically program Crunches as part of a core circuit that will include 2 or 3 other core exercises. 1 to 2 sets of 15 to 25 reps.

Benefits of Crunches

Crunches are a core exercise that can be used to strengthen the abdominal muscles.

Crunches require zero equipment, making them an extremely versatile exercise that can be done pretty much anywhere at any time.

Finally, Crunches are extremely beginner-friendly. They are easy to learn and easy to perform, yet can still be a very effective movement for developing core strength.

Muscles Worked

Muscles Worked - Rectus Abdominis
decade3d – anatomy online /

Crunches primarily work the Rectus Abdominis.

The Tensor Fasciae Latae (TFL) and Quadriceps Femoris are also working due to the legs being held in the air. Placing your feet flat on the floor instead of up in the air would turn these off.

By twisting alternatively from side to side (which we’ll discuss further in the crunch variations), you can place a much higher emphasis on the Obliques.

Crunch Variations

What to change your workout up just a bit. Here are a couple of Crunch variations:

Oblique Crunches

By adding a little bit of a twist to the crunch, you can target your obliques with Oblique Crunches. You can simply twist toward the top of the crunch, taking (one at a time) each elbow towards it’s opposite knee.

Or, to make things simpler, place one foot flat on the floor and rest the opposite foot on that knee. Now you can crunch up, taking the opposite elbow toward the knee that is now up in the air.

Weighted Crunches

If crunches start to become too easy, you can ramp up the difficulty by holding onto weight.

You can hold a dumbbell or a plate just over the chest and head area to add some extra resistance to your crunches.

Crunch Alternatives

If you can’t do crunches, for whatever reason, or you’re just wanting a different ab exercise option – here are a couple of Crunch alternatives:

Seated Crunches

Seated Crunches on Bench

For seated crunches, sit down on the edge of a bench with knees and feet close together.

Crunch by lifting your knees up towards your chest. Use your hands on the bench for support if necessary.

Sky Crunches

Sky Crunches are very similar to a crunch, but the position of the legs is different.

Keep the legs straight and laying straight down on the ground. Now, simply crunch straight up to the sky (hence the name!). Remember to keep your chin lifted up off your chest throughout the movement.

Exercises to Superset with Crunches

Looking to add some supersets to your program? Here are a couple of my favorite exercises to pair with Crunches:

Russian Twists

Russian Twist with Medicine Ball

Why: Russian Twists target the obliques, providing a comprehensive workout that complements the focus of crunches on the central abdominal muscles.

Mountain Climbers

Mountain Climbers with Right Knee Up

Why: Mountain Climbers engage both your core and lower body, enhancing overall stability and strength, which makes for a dynamic pairing with Crunches.

Need more superset options? Check out my 10 favorite exercises to superset with Crunches.

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Final Thoughts

Crunches are a great core exercise and I like to incorporate them both into the warm-up at lower volumes and at the end of workouts in higher volumes and usually combined with at least one or two other core exercises.

They’re one of those unique exercises that are both very beginner-friendly, yet still highly effective and used by elite-level athletes as well.

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