Crunches are a popular exercise that is often misunderstood. Find out how many crunches you should do a day for what goals.
The first thing to note is that crunches are a resistance training exercise for growing and strengthening your ab muscles.
To achieve this goal you preferably want to do 3 to 6 sets of 6 to 15 (weighted) crunches with resistance where you can barely complete these sets and reps.
Beginners will likely be able to build ab muscle with something like 3 sets of 10 crunches. As you get stronger, you need to increase the sets, reps, and/or resistance to keep seeing progress.
Keep in mind that even high-repetition ranges (around 50 reps) can still build muscle if you really push yourself to failure.
Another reason why people do crunches is that they believe this exercise will help them lose weight and more specifically belly fat.
However, to lose weight and body fat you should do 0 crunches a day and choose one of the many better exercise options for these goals.
Even with a good workout plan, lifestyle habits like nutrition play a big role in whether or not you lose belly fat and/or weight.
How many crunches you should do a day to build muscle
Crunches are mainly a resistance training exercise for your abdominal muscles. In simpler words, this exercise is mainly good for building and strengthening your ab muscles.
How you do crunches is not the only thing that influences your results in these areas. You also need to do enough repetitions, enough sets, use enough resistance, eat enough nutrients, and give your body enough rest.
Exactly what enough is for you depends on things like your current strength level, genes, and your workout plan. That being said, there are some general recommendations that can help you build muscle.
Most people think about lifting heavy weights when building muscle. Even so, to grow weaker muscles like your abs, bodyweight exercises can offer great results too.
While you likely have something that can serve as extra resistance, let’s say you only want to do crunches with just your body weight.
In that case, you want to do around 3 to 6 sets of 6 to 50 bodyweight crunches.
For beginners, a good crunch workout will likely look something like 3 sets of 10 crunches. Over time, you will likely need to increase your sets and reps to keep seeing progress.
Something to note is that if you do sets with 25+ repetitions, you really want to push yourself to muscle failure to see growth in your ab muscles (1).
If you are not improving in terms of how many repetitions you are able to do, you likely need to do more sets per workout, look at your nutrition and rest, and/or do weighted crunches.
To grow muscles you also have to pressure them with enough resistance. For weaker muscles like your abs, bodyweight exercises like crunches can stay effective for a long time.
However, even with that in mind, you could reach a point where you need to do crunches with weights to keep seeing progress.
These are simply crunches where you hold some type of weight, even just a household object like a heavy backpack, against your upper chest to make the movement harder for your abs.
To build muscle with weighted crunches, you want to do about 3 to 6 sets of 6 to 15 repetitions with a weight where you are barely able to complete these ranges.
You could also still grow your abs with the higher-repetition ranges from above but these tend to be less convenient and effective.
One of the upsides of weighted crunches is that you can do low-repetition sets and still build muscle and strength.
Is it OK to do crunches every day?
During resistance training exercises like crunches, you damage the muscles you work. This may sound bad but it starts a variety of internal processes that can repair the muscles and make them bigger and stronger.
However, your body still needs time to complete these processes. If you work the muscles again too soon, you could interrupt the growth and actually reduce your results.
That is why it is generally recommended to give muscles at least one rest day before challenging them again.
That being said, smaller muscles like the abs you work with crunches tend to recover more quickly than bigger muscles. Especially if you do weighted ones and don’t quite push to failure.
So for many people, it will be OK to do crunches every day.
At the same time, you can also already see great results when doing crunches 3 to 4 times a week. Implementing rest days can give you time to do other exercises and helps you stay further away from overtraining.
How many crunches you should do a day to lose belly fat
Next, many people also turn to ab and other core exercises because they think these are helpful for losing weight and more specifically belly fat.
However, just because you feel the muscles in a certain area “burning” does not necessarily mean you are using up energy (body fat) in this area.
To lose weight you have to make it so your body requires more energy (measured in calories) than is coming in from food. At this point, you start using up energy stores like body fat to get the differences.
That being said, even if you start losing body fat, that does not necessarily mean you are losing belly fat. Where your body uses fat from is generally not something you can influence significantly.
Additionally, crunches are not that great for burning calories either. As a first example, a 155-pound (70 kg) person will burn around 51 calories while doing bodyweight crunches for 15 minutes.
One pound (0.45 kg) of body fat is around 3500 calories and let’s say you do about 30 crunches per minute.
With these details, you can calculate that a 155-pound (70 kg) person would have to do about 30883 crunches to burn the number of calories in one pound of body fat.
Even then, whether these calories will actually come from body fat depends a lot on other lifestyle habits like your diet. It is generally not recommended to do crunches to lose belly fat.
The information above is useful but it may be a bit too theoretical for you. Luckily there is also a study with real-life results.
24 study participants were divided into two groups. One group did 6 weeks of an abdominal exercise training program (so not only crunches). The other group did nothing as a control.
The researchers measured that there were no significant effects of the ab exercises on details like body weight, body fat percentage, and abdominal circumference (2).
While there were likely some small differences, these were not big enough to reach statistical significance.
So again, the crunch and its variations are generally not good exercise choices to lose weight and more specifically belly fat. Even if you do them 7 times a week.
How many crunches burn 100 calories
Even though the information above still applies, you could also see the calorie-burning of crunches as a nice side effect of your ab workouts.
In that case, it can still be interesting to see what you can expect in this area.
Keep in mind that the amounts below are very rough estimations. In reality, the numbers can look different for you due to reasons like body composition, hormone levels, and crunch intensity.
That aside, let’s say the average person does about 30 crunches per minute. In that case, a 185-pound (83 kg) person would have to do about 735 crunches to burn 100 calories.
It should become clear that even something challenging like 100 crunches a day won’t do much in terms of calorie burning.
|Person Body Weight||Number Of Crunches To Burn 100 Calories|
|125 Pounds (56 kg)||1088 Crunches|
|155 Pounds (70 kg)||878 Crunches|
|185 Pounds (83 kg)||735 Crunches|
|215 Pounds (97 kg)||633 Crunches|
Better exercises for this goal
When it comes to burning calories in both the short and long term, there are plenty of exercises that are more useful than crunches.
To focus more on burning calories in the short term, you can do cardiovascular exercises like running, cycling, swimming, rowing, etc.
If you really want to get a lot of muscle mass and all of the extra energy usage that comes with this, compound resistance training exercises like squats, deadlifts, pull-ups, bench presses, and bent-over rows will be better.
That being said, even with a good workout routine you can gain body and more specifically belly fat with suboptimal habits in other lifestyle areas like nutrition.
How many crunches you should do to get visible abs
Everyone has ab muscles but it can be challenging to really get visible six pack abs. To achieve this fitness goal you have to take two main steps.
First of all, you need to lose enough of the belly fat covering your abs.
You can be a core training beginner or have the biggest ab muscles in the world but with fat above your abs, you won’t see them.
Crunches are not that useful in this first step in terms of burning calories but you could already implement them for their other benefits.
Once you get to a low body fat percentage, crunches can really help you get more visible abs. How many crunches you want to do at this point is the same as the muscle-building ranges above.
That means about 3 to 6 sets of 6 to 15 weighted crunches with resistance where you are barely able to complete these ranges.
Potentially another option is 3 to 6 sets of 6 to 50 bodyweight crunches where you really push yourself to failure.
Do you gain muscle from crunches?
With the right repetitions, pressure, nutrition, and rest, you can gain ab muscle from doing crunches.