The Pros and Cons of Crunches & Other Ways to Tone Your Core

Published September 21st, 2021 by Chris Riley
Fact Checked by
Jacqueline Hensler
Updated Date: Jun 30th, 2022

How to do a Crunch | Muscles | Pros and Cons | Differences with Sit Ups | Other Exercises

Crunches are one of the most common exercises you'll see people doing at the gym, but how do crunches work?

What muscles do crunches work?

What are the pros and cons of crunches?

And what is the difference between a sit-up and a crunch?

As it turns out, there's more than meets the eye to crunches. Read on for an in-depth look at these popular ab workouts and others to tone your core. 

How do you do a crunch?

Crunches are an easy way to get started working out your ab muscles if you've never done this type of exercise before, and crunches can be done almost anywhere.

At the gym on a mat or machine with weight added.  At home with no equipment needed or even in an office cubicle.

You might find crunches to be more effective when you do them isometric style, which means holding your legs still, as opposed to any regular type of crunch.

Crunches are done by lying flat on your back with knees bent over hips (or straight legs if that's too much strain), hands behind head or crossed across chest, then lifting upper body towards knees so your shoulder blades come off the ground.

Hold briefly, then slowly return to starting position. To do crunches with weights, hold a weight under your chin or behind your head throughout the set.

What muscles do crunches exercise?

Crunches work out your rectus abdominis, or six-pack muscles. Many people do crunches to get that sexy V-shaped torso and washboard abs you see in magazines.

Because crunches work the rectus abdominis, or the muscles on the front of your stomach known as your abdominal muscles or abs, they're the most popular exercise for strengthening that muscle group and getting rid of love handles.

However, crunches don't necessarily burn many calories or tone your entire core, so it's not as effective at toning your abs as high-intensity interval training exercises such as running sprints, cycling uphill, etc., which also strengthen multiple muscles in the lower body while elevating heart rate more than crunches can alone. 

Perhaps another reason why crunches have become so popular is that they're easy to learn how to do without any equipment needed, no heavy weights necessary here.

Also, crunches don't require a lot of time compared with other ab workouts like sit-ups or leg lifts which may take several minutes per set (or longer if using weights).

The convenience can't be beaten as you can do crunches just about anywhere.

What are crunches not good for? What are the cons of crunches?

There's no doubt that crunches work out your abdominal muscles which is great to have a firm midsection but there's more than one way to tone your core besides crunches.

Some people who don't get results from doing basic crunches may need additional weight training in order to build muscle and burn fat. We will highlight various other crunches to help with your workouts below.

Crunches might be easy to learn how to do without any equipment needed, but they're still an advanced exercise and many people start off by learning other ab workouts first like planks, before moving on to crunches.

In addition, crunches don't help with lower back pain which is another reason why it's important to work your full core and not just the top portion of your stomach.

Although crunches work your abs, your abs are the only focus and this is the biggest con. If you wanted to work your obliques, which are on the sides of your stomach, then you would need other exercises.

It is not a comprehensive core workout but it can be great for toning your abs. 

As with any exercise, there are risks of injury. Should you feel pain or injure yourself, please see your healthcare provider.

What is the difference between crunches and sit-ups?

Although both crunches and situps are popular ab workouts that do work out your abs, there is a distinct difference between crunches vs sit-ups: how you perform them.

We detailed how to do a crunch above but let's recount how to do a sit-up.

Sit-ups usually begin in the same position, your legs bent, feet flat on the ground with hands behind your head or crossed across your chest (or straight arms if that’s too much strain).

Lift your upper body from the floor toward your knees so your whole torso comes off the ground with only your feet and butt touching it until you are seated on the ground with your folded legs in front you.

Then slowly lower your torso back down to the ground. 

Sit-ups have been considered an advanced ab exercise because starting at a sitting position requires more core strength than crunches which hold briefly in the same crunched position.

However, crunches can be more challenging than sit-ups because your back is on the ground and you are lifting only from your abs – not using any of lower body muscles as with sit-ups which use your legs to help lift your upper body off the floor.

Sit-ups also pose a higher risk of injury due to the increased motion and the pulling of your hands on your neck

What other exercises can I do to strengthen my core?

Crunches can tone your abdominal area but our ab workouts should involve more than just cranking out standard crunch after crunch, our bodies need variation.

Here is a list of exercises you may want to consider instead of crunches (although two are a variation on the standard crunch): planks, bicycles, or twist crunches.


Plank exercises strengthen your entire body and are a great workout for your back and core.

It's good if you want to work up to crunches or sit-ups because it requires basically the same muscles as those exercises but targets them more intensely than crunches since you're holding yourself still rather than moving.

Planks help prevent lower back pain and improve posture by strengthening the abdominal area and spine stabilizing muscles, like your core.

You can try different variations of this exercise: side planks, leg lifts, or even one-arm planks.

How do you do a proper plank? It's easy, just follow our simple instructions below:

  • Balance on elbows with forearms flat on floor and hands directly below shoulders.
  • Tighten abs while pulling navel toward spine. Keep your neck relaxed so your head is in line with your spine.
  • Hold your body in a straight line from head to heel.
  • Hold this position from 10 to 30 seconds or as long as you can hold it and repeat.

Bicycle crunches

Bicycle crunches are a great way to ramp up your crunch regimen while also working out more muscles than your abs.

They start out in the same position as a crunch but add a twist. You can do bicycle crunches by following these simple instructions:

  • Lie flat on your back with your legs folded up at the waist but your lower legs perpendicular to the floor and not touching it with your feet.
  • Place your hands behind your head. 
  • Bring your shoulder blades off the floor as if doing a crunch.
  • While lifting your shoulder blades off the floor bring your right elbow over to touch your left knee.
  • Bring your shoulder blades back down to the floor and repeat the crunch motion. 
  • Alternate between bringing your right elbow to your left knee and your left elbow to your right knee.
  • Repeat as long as desired. 

This type of crunch helps work more than your abs and your legs look like you are pedaling a bicycle; hence, the name. 

Reverse crunches

Another variation on the standard crunch is the twist crunch and just like bicycle crunches, it works out more muscles than a standard crunch.

To do a reverse crunch follow these instructions:

  • Lie flat on the floor with your legs bent and feet flat on the ground. 
  • Lift your feet off the ground and raise them until they are parallel with the floor.
  • Bring your thighs and legs back into your chest as far as you can until your lower back is off the ground. Only your legs, hips, butt, and lower back should be off the mat while your mid and upper back stay on the floor. 
  • Slowly bring your legs back down to your starting position. 
  • Repeat. 

This exercise helps to strengthen other core muscles like your transverse abdominis and obliques. 


Crunches are one of the simplest and most convenient exercises one can do. It is a very focused exercise on your abs that can help with toning and are not as stressful on the body as sit-ups.

When crunches and sit-ups become too easy, it's time to try something new like planks or bicycle crunches that will help you work out more of your core muscles than just cranking through a few reps of your standard crunch.

By following the instructions for these simple exercises you can help keep your abs toned while strengthening the rest of your core. So start your crunches regimen today.

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