How Many Crunches Should I Do A Day? 4 Influential Factors

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Crunches are one of the most popular go-to ab exercises, especially among beginners. 

Most people have some familiarity with performing the basic crunch. Even if it has been years since you set foot in a gym or have tried working out at home, doing crunches often feels like a doable and approachable starting place before attempting more complicated exercises or mastering more challenging movements.

But you may ask yourself: how many crunches should I do a day? How many crunches a day to see results?

Keep reading to find out if crunches are a good exercise for you and how many crunches a day will help you reach your fitness goals.

In this article, we will cover: 

  • Are Crunches Good for You?
  • How Many Crunches Should I Do A Day?

Let’s jump in!

A person doing a crunch.

Are Crunches Good for You?

Although crunches are indeed beginner-friendly and can help strengthen your abdominal muscles, doing crunches is not the most effective way to strengthen your abdominal muscles or improve functional core strength. 

Additionally, for certain populations, performing crunches is contraindicated because of the flexion it imposes on the spine.

For example, if you suffer from osteoporosis or low bone density in your spine, or you have degenerative joint disease in your spine, spinal stenosis, or herniated discs, doing crunches can increase your risk of further damage, such as causing vertebral compression fractures or exacerbating narrowing between your vertebrae.

Women who are pregnant, or men or women who are dealing with diastasis recti, should also avoid doing crunches because of the increased intra-abdominal pressure and positioning inflicted by the crunch movement pattern.

Alternative core exercises that do not require final flexion are recommended in all of these cases. Examples include forearm planks, high planks, side planks, bird dogs, dying bugs, and potentially more dynamic exercises such as medicine ball chops.

People doing planks in a gym class.

How Many Crunches Should I Do A Day?

One of the most common questions that personal trainers are asked by their clients is, “How many crunches a day should I do to see results?”

Unfortunately, there is no simple or single answer to this question.

For one, crunches are not going to be the most effective ab strengthening exercise you can do, so even if you do hundreds of crunches per day, you may not achieve the aesthetic and strength gains you are looking for, or at least not as efficiently and effectively as you could if you chose other core exercises or performed a more well-rounded core strengthening routine.

With that important consideration aside, the answer to how many crunches should I do a day to see results will really hinge upon numerous factors such as the “results” you are looking for, your overall workout routine (what other exercises you are performing, if any), the types of crunches you are doing, and your diet.

Different answers to each of these variables will affect how many crunches you should do per day.

Let’s look at each of these factors individually.

A class of people doing crunches on Bosu balls.

#1: The Results You Are Looking For

When asking, “how many crunches should I do a day to see results?“ it’s important to establish what “results“ you are looking for.

What is your goal when doing crunches? Do you want to lose weight? Do you want to increase the strength of your abdominal muscles? Do you want to see definition in your abs or achieve a “six-pack “?

Ultimately, just doing crunches will not be a very effective way to achieve any of these three goals, but each will influence how many crunches you will need to do per day, regardless.

If your goal is weight loss, you will need to do tons of crunches because this exercise burns very few calories.

You will be much better off performing a well-rounded fitness routine with aerobic exercise and total-body strength training workouts 4 to 6 days per week, striving to generate a caloric deficit by also restricting your caloric intake through your diet and burning more calories with your exercise and physical activity.

A person doing a crunch.

If your goal is to increase strength in your ab muscles, aiming to do three sets of 12 to 20 crunches per day is a good starting place, depending on your fitness level and any other ab exercises that you are throwing into your core workout routine.

As you get stronger, you can add resistance to your crunches by either crunching against the resistance of an exercise band or cable machine or doing a weighted crunch with a dumbbell, medicine ball, or another weighted implement.

If the crunches results you are looking for are centered around seeing defined abs, the number of crunches you should do per day will depend on your current body composition and how far you have to go to achieve the physique you are desiring.

In most cases, seeing visible muscle definition or tone is more a matter of losing excess subcutaneous body fat than it is building significant muscle, which brings us back to the first goal of aiming to lose weight by doing crunches.

A person doing a bicycle crunch.

#2: Your Diet

The popular saying, “Abs are made in the kitchen,“ speaks to the fact that your diet plays a significant role in your weight loss success and the definition and tone you will see in your abs.

Many people want to know how many crunches to do per day to lose belly fat, and the truth is that you cannot spot-produce body fat. 

No number of crunches will selectively melt away excess fat on your belly any more so than burning the same number of calories doing a total body exercise or an exercise that targets another major muscle group.

If you are aiming to lose belly fat by doing crunches, the best thing you can do is follow a calorie-controlled diet and perform a well-rounded fitness routine, aiming to generate a caloric deficit of 500 to 1000 calories per day in order to lose 1 to 2 pounds per week.

A person doing a crunch.

#3: The Type of Crunches You Do

Everyone is familiar with the saying, “Variety is the spice of life.” When it comes to your fitness routine, this often overused saying still rings true.

Your body thrives on a varied workout routine that includes lots of different types of exercise to target all of your major muscle groups in various ways.

Rather than doing basic crunches every day with your feet flat on the floor, knees bent and contracting your abs to raise your shoulder blades off the ground before returning to the starting position, perform different types of crunches on the same day or different days during the week to work different abdominal muscles.

For example, you can do bicycle crunches to target your obliques which are the muscles on the sides of your torso.

You can do reverse crunches with your back flat on the ground, and your knees and hips bent to 90° with your feet up in the air and then lower them slowly to target your lower abs.

There are also stability ball crunches, weighted crunches, and decline crunches. In fact, there are quite a number of types of crunches. Crunches should only be a small piece of your core routine if included at all.

The guiding principle should be that the more variety you can add to your core routine, the more effective your crunches will be.

With each type of crunch exercise, aiming to do three sets of 12 to 15 reps is a good general guideline for most beginners and intermediate athletes.

A person doing a crunch.

#4: Your Overall Workout Routine

The best fitness routines are well-rounded and balanced, meaning that they include lots of different types of exercise that work all of the major muscle groups in your body. You should include both cardio and strength training exercises and vary the types of exercises you do.

Crunches should not be the only strength training exercise that you are performing. If you are already doing a bunch of other core exercises in your workout routine, such as planks, Pallof presses, V-ups, etc., you can and should get away with doing fewer crunches a day than someone who is relying almost solely on crunches to strengthen the abs.

Overall, it can be seen that the number of crunches you should do per day depends on numerous factors, but a good general recommendation is to perform three sets of 12 to 15 reps. 

However, try to perform a variety of crunches and, most importantly, consider alternative core exercises that will be more functional, safe, and effective than crunches.

Check out our 20 Plank Variations to spice up your core workout!

A person doing a crunch.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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