Core workouts can be surprisingly versatile. Find out how to do runner’s crunches, what their effects are, and what alternatives can be better.
Runner’s crunches are a crunch exercise variation where you move one shoulder and the knee of the opposite side towards each other while moving your arms similar to running.
Compared to regular crunches, runner’s crunches mainly work your obliques and to some extent your lower abs more.
In simpler words, runner’s crunches are mainly useful for growing and strengthening your ab and oblique muscles.
At the same time, it is worth mentioning that all of the arm and leg swinging in runner’s crunches is actually not necessary or useful.
Just doing sideways crunches can even be more effective since there is no way you use the swinging of these other body parts to raise your shoulders.
How to do a runner’s crunch
Similar to many floor core exercises, using a yoga mat or another soft surface in runner’s crunches is typically helpful in terms of comfort.
That being said, take the following steps to do a runner’s crunch:
- Lie down on your back with your feet flat on the ground in front of your butt. Keep your elbows at 90-degree angles.
- Slowly move up one knee and the shoulder of the opposite side until they reach the middle. These movements should come as much from your core muscles as possible. Let your lower leg follow gravity.
- Lower your shoulder and leg to the position in step 1 in a controlled motion.
- Repeat the same movement with the opposite arm and shoulder.

The main thing to keep in mind is that you don’t want to use the swinging of your body parts to raise your shoulders and hips.
You want your core muscles to make these movements happen. If these muscles are not fatiguing your technique is likely suboptimal for a core workout.
Doing runner’s crunches at a slow pace can help you with implementing a good technique.
That aside, if you consistently do runner’s crunches over time, you may notice that the bodyweight version becomes a bit easy.
In that case, doing the exercise with crunch exercise equipment options like for example a dumbbell can help you get more results faster.
Runner’s crunches muscles worked
If you do them right, runner’s crunches are mainly a core muscle (obliques and abs) isolation exercise.
Your hip flexor and shoulder muscles may have to work to a certain extent to raise your legs and arms.
Besides that, your biceps and triceps have to work to a tiny extent to keep your elbows at the same angles too.
That being said, while you do engage these secondary muscles to some extent, runner’s crunches still mainly work your obliques and abs.
To actually grow and strengthen these muscles with this exercise you do still need a good workout routine.
Runner’s crunch benefits
It is true that runner’s crunches implement arm and leg movements and more focus on your obliques. At the same time, their positive effects will still be similar to regular crunch benefits.
Some examples include:
- Stronger muscles: Doing runner’s crunches with enough weight, reps, and sets can help you grow and strengthen your obliques and abs.
- May reduce or prevent back pain: Strengthening your core muscles can reduce or prevent back pain (1, 2). You do want to be careful about doing more runner’s crunches if you currently have back pain.
- No equipment or location required: You only need your body to be able to do runner’s crunches. This requires less money and time investment in equipment or transport.
- Make your abs more visible: After your body fat is low enough, growing your ab muscles can make your six-pack more visible. This is typically considered to be visually attractive.
As briefly mentioned, runner’s crunches are not necessarily the best way to get these benefits. Other core exercises could be more effective.
Runner’s crunch alternatives
Doing runner’s crunches can offer great benefits but other exercises can do similar things. Sometimes in more effective ways.
Some runner’s crunch alternatives you can consider include:
- Oblique crunches
- X crunches
- High knees
- Bicycle crunches
- Sideways leg raises on the captain’s chair
Which one of these options is the best depends on things like your personal situation, training goals, the equipment you have available, etc.
Is the runner’s crunch a good exercise?
Runner’s crunches can be a good exercise to work your obliques and ab muscles. In turn, this can lead to benefits like preventing back pain and getting a more visible six-pack.
At the same time, it is worth mentioning that the extra arm and leg movements in runner’s crunches are not that useful. They could even interfere with your core training.
For this reason, you likely want to choose one of the runner’s crunch alternatives instead.
No matter what core exercise you choose, keep in mind that more experienced lifters may need to add resistance to these movements to see a lot of results.
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FAQ
What is runner’s crunch?
A runner’s crunch is a crunch variation where you lift your shoulder sideways, move one arm up, and move one knee up at the same time. This works your obliques more than the regular crunch.