You can do the standard crunch with many different modifications. Find out how to do frog crunches and what their benefits are.
Frog crunches are a crunch exercise variation where you start with your heels against each other and knees pressed down to the side.
After that, you not only raise (“crunch”) your shoulders but also your hips and legs.
In turn, frog crunches work the lower part of your abs slightly more on top of the regular abs workout. This variation can also help you stretch your inner thigh muscles to some extent.
So frog crunches are mostly useful for growing and strengthening your ab muscles.
The extra stretching is welcome but not that effective compared to stretching sessions you could do outside of your core workouts.
How to do a frog crunch
It is typically recommended to use something like a yoga mat while doing frog crunches. This will make the movement more comfortable on your back.
That aside, take the following steps to do a frog crunch:
- Lie down on your back and put the heels of your feet against each other. Additionally, move your feet as close to your body and knees as close to the ground as comfortable. Hold your arms against your chest.
- Raise your shoulders as far as comfortable in a controlled motion while keeping your lower back against the ground. At the same time, tilt your hips back and raise them from the ground as much as comfortable.
- Slowly lower your shoulders, hips, and legs until you are back in starting position. If your set is not done yet, you can keep your lower back pressed against the ground for now.

The main thing to pay attention to in frog crunches is not swinging your head back and forth too much. For this reason, you typically don’t want to put your hands against your head.
Additionally, you want to make sure your movements come from your ab muscles. Don’t swing your arms and legs around too much.
It is possible that bodyweight frog crunches become too easy to see the results you want over time.
One way to make them slightly harder is to stretch your arms above your head.
Even better is doing frog crunches with some type of weight in your hands or legs.
Frog crunches muscles worked
Frog crunches mainly work your ab muscles. Compared to regular crunches they will engage the lower part of your ab muscles slightly more.
To actually grow and strengthen your ab muscles with frog crunches you still need to approach your core training the right way.
For a fitness goal like growing your abs, that would mean doing around 6 to 25 (or even up to 50) frog crunches with weights where these numbers are challenging to complete.
This means you will have to use more pounds and kilograms as you get stronger to stay within these ranges.
Frog crunches benefits
Frog crunches are a bit different from the regular version in that they involve more stretching and more focus on your lower abs.
Besides these things, the positive effects of frog crunches will be very similar to the regular benefits of crunches.
In simpler words, some of the positive things you can expect from frog crunches are:
- Muscle growth and strength progress: Doing frog crunches in a good exercise routine can grow and strengthen your abs.
- Flexibility and mobility: Doing frog crunches could help improve the range of motion of certain body parts. In simpler words, this exercise can improve your flexibility and mobility.
- May reduce or prevent back pain: You want to be careful with frog crunches if you have any back pain. However, frog crunches could also reduce the extent of or prevent this issue (1, 2).
- No equipment or location required: You don’t have to invest in any equipment or move anywhere to be able to do frog crunches. This benefit can save you money and time.
There are other ways to get these benefits too but they could make frog crunches a worthwhile addition to your exercise routine anyway.
Potential risks
You want to keep in mind that some people will find frog crunches uncomfortable in areas like their back, hips, inner thigh muscles, and neck.
If these are issue areas for you, you likely want to approach frog crunches carefully. You don’t have to push your knees completely against the ground to be able to get positive effects from this exercise.
People who do still find the spine bending involved uncomfortable can consider isometric (static) ab exercises instead.
Frog crunch alternatives
Doing frog crunches can improve your life in a few ways but they are not the only exercise that can do this. A few examples of frog crunch alternatives are:
- Regular crunches
- Inner thigh muscle stretches
- Reverse crunches
- Hollow body holds
- Knee raises on the captain’s chair
- Lying leg raises
Details like your training goals, preferences, and fitness equipment you have available will influence what frog crunch alternatives are good for you.
Is the frog crunch a good exercise?
Frog crunches can be a good exercise for working your upper and lower ab muscles at the same time.
You should likely not expect too much from the inner thigh muscle stretching but this could be somewhat beneficial for flexibility and mobility.
Something to note is that people with strong abs may need to do frog crunches with crunch equipment to see a lot of muscle growth and strength progress.
That being said, you can also do other crunch variations that work both your upper and lower abs and do your inner thigh stretches separately.
How much you like doing frog crunches influences your choice to some extent too. Enjoying your workouts could make it easier to stay consistent with your plan.
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FAQ
What are frog crunches good for?
Frog crunches are mostly good for working your lower and upper abs. You also get a small amount of inner thigh muscle stretching.
What is a frog crunch?
A frog crunch is a variation where you keep the heels of your feet against each other, keep your knees low, and raise both your hips and shoulders.