Doing an exercise like crunches just a few times is often not enough for significant results. Find out whether 20 repetitions a day is enough.
To grow and strengthen your ab muscles you need to pressure them with enough weight and repetitions.
If you are barely able to do the 20 bodyweight crunches a day in 2 sets of 10 repetitions to 4 sets of 5 repetitions, you will likely be able to see at least some ab muscle growth.
That being said, as you get stronger over time you will likely have to start using extra weight and/or do more crunches per workout to keep seeing muscle growth results.
Besides that, starting with something easy and short like 20 crunches a day can be helpful to get into the habit of working out.
At the same time, you really want to consider more intense workouts if you are somewhat serious about your health.
Is 20 crunches a day enough to build abs?
To grow and strengthen muscles like your abs you need to put them under enough pressure and do enough repetitions.
Exactly what counts as enough depends on your current strength level and body. That being said, there are some general guidelines to figure out what 20 crunches a day can do for you.
If you are barely able to do something between 2 sets of 10 crunches and 4 sets of 5 crunches, doing 20 repetitions a day could just be enough to grow your ab muscles.
For people who are new to ab resistance training, bodyweight crunches could be enough to stay within these ranges.
However, as you get stronger over time, you will likely need to do crunches with weights to keep the 20 repetitions a day challenging enough for muscle growth.
Even if you do this, you may need to consider doing more crunches per workout to keep seeing progress in this area.
Lastly, to work other core muscles like your obliques, you can switch your workouts up with different types of crunches too.
How many calories do you burn with 20 crunches?
Growing and strengthening ab muscles is the main purpose of crunches. That being said, because you are likely moving more intensely than usual, you will also use up more energy.
Exactly how many calories you burn with crunches will depend on your body weight, hormone levels, body composition, exact intensity, etc.
That being said, there are ways to make rough predictions. These are not perfect but do give you an idea about what you can expect from doing 20 crunches.
The average person will do around 30 crunches per minute. With this information, you can estimate that people with different body weights will burn the following amounts of calories with 20 crunches:
- 125 pounds (56 kg) body weight: 2 calories
- 155 pounds (70 kg) body weight: 2 calories
- 185 pounds (83 kg) body weight: 3 calories
- 215 pounds (97 kg) body weight: 3 calories
These are rounded numbers but they do make the point clear. Spending 2/3 of a minute on doing 20 crunches will barely burn any extra calories.
And even if you would do 300 crunches a day or more, this would still not be a great exercise for burning calories compared to many of the other options available.
It can help you build an exercise habit
Even to grow and strengthen your ab muscles, 20 crunches a day is a relatively short and light workout. That being said, this can be the good thing about this routine depending on who considers implementing it.
When you first get interested in exercising more, hour-long workouts with types of weights you have never seen before can feel too overwhelming.
If you start with these, you could end up not doing any exercise at all.
However, by starting with something simple and light like 20 crunches a day, it becomes easier to build an exercise habit.
As you get more used to this, you can start increasing the intensity and duration of your workouts to get the health benefits to a larger extent.
Ways to see more results
Sooner or later you will likely get to a point where you are physically and mentally strong enough to do more than 20 bodyweight crunches a day. In that case, there are a few ways to go depending on what your fitness goals are.
As mentioned before, you can start with doing crunches with extra weights against your chest to see more ab muscle growth and strength progress.
Another way to do this is to increase the number of repetitions you do. How many crunches you need to build muscle will depend on your body and strength level.
However, doing more repetitions per week will typically increase your ab muscle growth results as long as you are not overtraining and giving your body enough nutrients.
If you are interested in burning more calories with your workouts, you likely don’t want to do (a lot of) crunches. For this goal, compound lifts with big muscles and cardiovascular exercises tend to be more effective.
People who are interested in losing weight also want to remember that other lifestyle habits like diet play a big role in this process. You can exercise a lot and gain weight with suboptimal habits in these other areas.