Everything About Crunches vs Sit Ups for Fitness

Crunches vs Sit Ups. You do not need to do 1,000 crunches to have a six pack. You also do not need to do endless sit ups to have a strong core. Having a six pack is all about having a low body fat percentage. If you want a more solid core, you need to work your abdominal muscles. Our conversation begins on figuring out if you should do crunches or site ups. What is better for fitness, Crunches or Sit Ups?

What is the difference between crunches and sit ups?

crunches vs sit ups

(Don’t be this guy – he is doing it wrong.)

To know what is better in the battle of crunches vs sit ups, you need to know the difference between the two. The single most important thing to know is that crunches and sit ups are different. Entirely different. A sit up is a multi muscle exercise. A crunch is only an upper abdominal muscle exercise.

When you do a crunch, you are pulling your head up as you contract your upper abdominals. A sit up involves bringing your chest to your knees. Neither exercise is great at burning fat, but they both can build muscle.

What is a Sit Up?

Sit Ups focus on working your chest, neck, lower back, hip flexors and abdominal. That is the strength of a sit up; it works a large variety of muscle groups. Since any exercise is designed to build muscle, you can’t get a flat stomach with just exercise. Targeting and strengthening multiple muscle groups will build more muscle and lead to burning more calories in the long run.

The biggest down fall of a sit up is the risk of injury. It can cause extreme lower back and neck pain. If you are in poor shape, you should avoid any abdominal exercise. The fact is, this type of exercise is extremely prone to injury. If you insist on doing a sit up, you need to know how to do one.

How to do a Sit Up:

  1. Put a mat on the ground (A hard surface can contribute to injury).
  2. Get on your back, and lay flat.
  3. Bend your knees and have your feet flat on the ground (This will stabilize your lower body to prevent injury).
  4. Your feet should be between 10 – 12 inches from heel to the buttock.
  5. Your feet should be shoulder width apart.
  6. While laying down, cross your arms and hold onto the opposite shoulder (Right arm holds left shoulder, left arm hold right shoulder).
  7. Curl by pulling on your shoulders, lift your chest to touch your knees.
  8. Exhale as you curl to your knees.
  9. Once your chest touches your knees, slowly lower yourself flat.
  10. Exhale as you lower yourself.

What you must avoid is holding your head when doing a sit up. This causes unnecessary neck tension which can cause injury. Start in groups of ten reps and work your way up.

What is a Crunch?

crunches vs sit ups

I can tell you what a crunch is not, a fruity cereal. A crunch is an isolation exercise which targets your abdominals. This includes your lower back muscles and obliques. No other exercise comes close to the ability of a crunch to build your upper abdominal muscles. Sadly, that is also the biggest down side of a crunch; it does nothing for your other muscle groups.

How to do a Crunch

  1. Follow sit up instructions up to step six.
  2. Tuck your chin to your chest.
  3. Constrict your abdominals.
  4. Lift your head from the ground.
  5. Inhale and rise until your shoulders are off the ground.
  6. Exhale as you lower back to the ground.


The risk of injury is greater for crunches than sit ups, but crunches do a fantastic job of strengthening your core. This includes improving your balance and improving your posture. The biggest difference between sit ups and crunches is that crunches only work your abdominal muscles and have a higher risk of neck injury, while sit ups work for more muscle groups and have a slightly lower risk of injury.

 Battle Royal: Crunches vs Sit ups

Each exercise has a place in your routine. For a stronger core, you would focus on crunches. This is optimal for active people or athletes who are lean and could use core stability for performance. Sit ups will improve posture and other muscle groups such as your lower back.

Lower back pain and problems is a common issue for people as they age. If you do not need a stronger core, stick with sit ups. Crunches have a higher risk of neck injury and in large part are being slowly faded away from common fitness routines.

Should You do Crunches vs Sit ups?

I say no. Unless you need the improved performance from a stronger core, the risk of injury is too great when it comes to sit ups. You are likely to get hurt when doing sit ups or crunches. Add in the fact that crunches and sit ups do not directly help burn fat; you simply do not need to do them.

To burn fat or build muscle, you are better off trying a body recomposition protocol. The only way to have visible abs is to lose body fat. Crunches vs Sit ups? Your crunches will not give you abs, no matter how many you do.

Find all the resources used in this article and the scientific basis of all our article at The Science Behind Fitness.


  1. Tayla August 26, 2017
    • Eric August 26, 2017
    • Mathiah McKinney September 2, 2017

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