How To Do Frog Crunches Properly

There are few core exercises that are quite as challenging as frog crunches.

This classic ab movement mimics the motion frogs make when swimming in water, hence the name ‘frog crunches.’

It activates your abdominal muscles, glutes and hip flexors all at once.

How to do it:

  • Lie on a mat facing up with the soles of your feet pressed together and your knees bent.
  • Without interlocking your fingers, place your hands on the back of your head.
  • Put your spine and pelvis in a neutral position so that your ribs are down and your pelvis slightly tucked.
  • Tighten your core and tuck your chin too. This is the starting position.
  • Begin moving upward by squeezing your core as you lift your legs and curl your shoulders off the ground.
  • Pause for a few seconds at the top position.
  • Slowly, extend your legs outward and lower your upper body to the starting position while still keeping your core tight.
  • Do 2-3 sets of 10-15 reps each.


This movement targets your entire abdominal wall, including your rectus abdominis (aka the six-pack muscles), the obliques at your sides and the transverse abdominis which is located deep in your midsection.

As you lift and extend your legs, it also recruits some of your lower body muscle groups including the hip flexors and inner thighs.



Frog crunches put your core to work, by making it stabilize your body as you move your chest towards your knees.

This way, you get to work your core muscles extra hard without losing the tension in there as you perform the movement.


You can easily modify frog crunches to make them easier or more challenging, depending on your preference.

For instance, you can keep your feet a few inches off the ground as you curl up your shoulders to increase the tension in your core and make the exercise more challenging.

Similarly, you can keep your legs stationary and your knees at 90 degrees so you don’t have to strain moving them with each rep.

This might reduce the tension in your core, but it will certainly make the exercise easier for you.


When performed correctly, frog crunches involve multiple muscles in your upper and lower body.

Unlike in the traditional crunch where your lower body remains still on the ground, this particular variation requires that you move your whole body to put your core under as much tension as possible.

This way, you get to work more muscles than just your core, for which this exercise is primarily intended.


The key to having good balance and posture is to build a strong core that will stabilize your spine and lower back.

Because it targets your core, the frog crunch can be used as a part of a posture strengthening routine.


Since you are rotating your hips externally with your feet pressed together, you will also be activating your adductors automatically.

Your inner thighs get to benefit a lot from the external hip rotation as you move your knees towards to your chest.



This is a traditional crunch variation that involves using a weight to increase resistance in your midsection as you crunch up.

How to do it:

  • Start by lying on a mat/floor, with your knees bent and pointing to the ceiling.
  • Hold a weight (e.g. a medicine ball or a dumbbell) at the center of your chest. Don’t let it rest on your chest though.
  • Curl up by peeling your shoulders off the floor without letting your chin touch the chest. The weight might move toward your midsection, but you should make sure you are holding it above you throughout so you can focus the weight on your core.
  • Lower your body down with control and repeat these steps as many times as you desire.


This is another crunch variation that will put just as much tension in your core as the frog crunch.


  • Lie on a mat/floor with your knees and hips bent at 90 degrees.
  • Bring both hands behind your head.
  • Keeping your legs stationary, exhale and curl your upper body up without letting your chin drop towards your chest.
  • Inhale and lower back down.
  • Do as many reps as you desire.



This is a core exercise; so if you fail to tighten your core then you will not gain anything from it.

Instead of using your neck, focus on initiating the exercise from your core and upper back.

An easy way to make sure your core is under tension is by lifting from your upper back as you bring your shoulder blades off the floor, then checking if you can see your belly button at the top position.


Try to maintain a neutral back by pressing your lower back into the ground so it doesn’t arch as you lift the shoulders off the ground.

If you notice your lower back lifting off the floor, try reducing the range of motion so that your legs are closer to your body.

This will help prevent pain or injury on your back.

As you core strength improves, however, you will find it easier to extend your legs with more control to get the benefits of this exercise without hurting or straining your back.


Every core exercise requires that you breathe throughout the exercise so that you fully activate the core muscles for a more effective workout.

Frog crunches are no exception; make sure you exhale as you crunch your body up and inhale and extend your legs.


You’ve probably come across-maybe even performed – so many different variations of the traditional crunch that you probably think this one will not be any different.

However, you really should give it a chance.

Not only will it work both your upper and lower abs for an extensive core workout, but it will also concentrate the tension in your core as you place your hands behind your head while performing it.

Also, it is easy to modify, so you can choose to make it easier or more difficult depending on your fitness level.

Try it out the next time you are working your core for a more comprehensive core workout.

All the best!