How To Do Crunches For the Best Ab Workout

With the holidays right around the corner, a lot of us are wondering how to stay on top of our fitness routines throughout the festivities. Crunches are one of the most popular — and portable — core exercises. That makes them easy to do whether you're traveling or watching T.V., so they’re featured in almost every kind of full-body workout from HIIT-style bootcamp to Pilates.

However, they’re also one of the exercises that I see performed incorrectly most often. Mastering the correct form not only will help you get the most out of your crunches, but it will prevent you from straining your neck and causing pain and injury.

Is a crunch or a sit up better workout?

Sometimes I’m asked if a crunch or a sit up is a better workout. The truth is that many people perform sit ups incorrectly. Heaving forward and overusing the low back or shoulders is a common mistake people make because they’re trying to sit up. It’s very challenging to use the abs and core correctly to do a proper sit up.

Therefore, I recommend that people start with a crunch. Perform a crunch without any neck pain first. Build your core strength. Then, you can move on to a sit up or a modified sit up. I’d rather you do an exercise correctly than do a more advanced exercise incorrectly.

Ultimately, a sit up does work more of the core than a crunch, but the likelihood of performing a sit up correctly compared to a crunch is lower!

What does a crunch do for the body?

Strengthening your core with crunches can improve overall core muscle function, and this can help improve sport performance and promote balance and stabilization in other exercises you perform. They also help improve posture and reduce belly fat.

The reason crunches are considered a go-to exercise is because they cause growth in muscle size, also known as hypertrophy, of the rectus abdominis muscle. So, if you’re looking to tone your ab muscles, crunches are the perfect move to master.

It’s worth mentioning that the core is made up of four muscle groups, and crunches target just one of those groups. It’s important to use crunches as part of a well-rounded core routine that works your abdominal muscles from every angle.

How many crunches should I do a day?

You may see gimmicky challenges out there like, "Do 100 Crunches A Day to Crush Your Abs!' Try to resist those fads. As a personal trainer, I recommend adding crunches into the ab routine you've already started and then increasing your core work incrementally. Doing 3 rounds of 10 crunches for a total of 30 is usually enough to make a difference.

I recommend creating your own workout routine — unless you’re already following one — and including 3 different ab exercises. For example, an ab routine may look like crunches, bicycle crunches, and lower lifts. You would do 10 crunches, 10 bicycle crunches, and then 10 lower lifts. Repeat that two more times for a total of 3 rounds and 30 exercises of each!

The common mistake people make when doing crunches

A lot of people — myself included before I studied physiology, personal training and Pilates — tend to pull their necks forward with their hands while crunching. This happens when you rely on your arms instead of your core to pull your body up and forward. This added pressure on your neck strains the muscles and causes pain.

Pulling your neck with your hands also leads to decreased core engagement. Crunches are a core-strengthening exercise, so not engaging your abdominals is a huge mistake. To correct this mistake when you perform a crunch:

  • Pull your navel in toward your spine and squeeze your abs, making sure your low back maintains contact with the ground.

  • Rest your fingertips gently behind your head, and be sure to keep your elbows wide pointed out toward the sides of the room (versus pulling forward toward your knees).

How to protect your back and neck

When you’re doing a crunch, you want to make sure that your head and neck are properly supported.

Here's how to keep your neck and back safe during crunches:

  • Place your hands behind your head and open your elbows out to the sides.

  • Lift your head and neck up off of the ground while supporting your head with your hands.

  • Allow your head to rest heavy in your hands. This maintains proper spinal alignment.

  • Relax your shoulders even though you are using your arms to hold your hands underneath your head.

  • Try not hunch your shoulders.

  • Pretend that you’re holding an egg between your chin and your chest, and you don’t want to crack it. Make sure your chin isn’t tilting down too far towards your chest or pointing up to high towards the ceiling. Hold that egg! This helps you to maintain proper alignment and also ensures your neck is not over engaged during the crunch.

How to do a modified crunch

If you’re unsure how to perform a crunch without straining your neck, try the modified version to work your core as you gain the confidence to tackle the full move.

  • Lie down with your back on the floor.

  • Bend your knees and place your feet flat on the mat.

  • Place your hands behind your head with your elbows wide.

  • From this position, lift your chest up only halfway.

  • Make sure to keep your knees bent and your shoulder blades off the ground as you tighten your abdominals.

  • Lower back to the ground. Repeat 10 times.

How to perform a crunch correctly


Performing a crunch effectively takes some practice. If you’re feeling confident, follow these step-by-step instructions to complete the crunch with perfect form:

  1. Lie down on your back with your knees bent, feet as wide as your hips and feet flat on the floor.

  2. Tighten your abs, pulling your belly button in toward your spine and making sure to engage your core throughout the exercise.

  3. With your hands placed gently behind your head and elbows wide, use your abs to bring your shoulder blades off the floor. Exhale as you lift your body.

  4. Slowly release the position, inhaling as your rest your head on the mat.

  5. Return to the starting position and repeat.

4 ways to do crunches

If you’re still feeling it in your neck, these exercises will help you build the strength needed to tackle a full crunch.

standing bicycle crunch
standing bicycle crunch

Standing bicycle crunches

This is the perfect move for beginners who want to practice engaging their core. Stand up straight with your hands behind your head. Lift your right knee up to your chest as you bring your left elbow down to meet the right knee. Then bring the left knee up and crunch the right elbow down to meet it. Continue alternating sides. Don’t forget to squeeze your abs!

Modified bicycle crunch
Modified bicycle crunch

Modified bicycle crunch

Sit on your butt with your legs bent and heels resting on the ground. Position yourself as if you had just pulled yourself up into the top of a sit-up. Place your hands behind your head with your elbows wide. Twist your torso to the right and bring your right knee to meet your left elbow, then twist your torso to the left and bring your left knee to your right elbow.

Boat pose
Boat pose


Sit down with your knees bent and feet flat on the ground. Lean back slightly, engaging the core and keeping the back straight. Hold your arms out straight in front of you as you lift your feet off the floor. Make sure to keep your legs together as you point your toes toward the ceiling and form a "V" with your body. Hold for 10 seconds. For a modification, keep the knees bent and open as wide as your hips, with shins parallel to the floor.

Modified forearm plank hold
Modified forearm plank hold

Modified forearm plank hold

Lie down on your stomach. Place your forearms flat on the mat and bend your knees so that they’re touching the mat. Engage your core and lift your body off the mat, balancing on your knees and forearms. You can stay here, or from this position, raise your knees off the mat so that you are one straight line from your head to your feet. Hold for 10 seconds, then return your knees to the mat. Repeat 10 times.

More ways to keep your core strong:

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