Flutter Kicks Guide: Muscles Worked, How-To, Variations and More

Flutter Kicks Guide

In this guide on how to do flutter kicks, you’ll learn about the awesome benefits of this simple, yet very effective exercise. The flutter or butterfly kick, as some call it, involves lying on your back and moving your legs in a similar motion that you do while swimming. In fact, swimmers actually do this exercise to improve their conditioning or endurance.

But it’s a bodyweight-only gem that’s also great for really emphasizing the lower abdominals in addition to engaging the entire core when done correctly. 

Not to mention, it’s a challenging but low impact movement that can burn a lot of calories which is ideal if you’re trying to shed some pounds.

So, today we’re going to convince you why it could be a worthwhile addition to your exercise regime. 

Muscles Worked

Lets’ first make clear the muscles that are working to help execute the flutter kick exercise.

Flutter Kicks

Core muscles  

The core muscles include the rectus abdominals (six-pack), the obliques (muscles on the outsides of the six-pack), deep core muscles, and even the erector spinae.

  • The sick-pack muscles (rectus abdominis) are responsible for trunk flexion or the forward bending of the trunk.
  • The obliques help with trunk rotation and lateral flexion.
  • The deep core muscles or transverse abdominis muscles compress the contents of the abdomen. 
  • The erector spinae muscles are responsible for trunk extension which allows us to stand up straight or bend backward.

Hip flexors

The hip flexors should only be minimally involved in this exercise otherwise, you’re doing it wrong and won’t feel it in your core where you should be feeling it.

The hip flexors are made up of the rectus femoris, iliopsoas, sartorius, and tensor fasciae latae muscles. 

These muscles flex the hip or allow us to raise our upper leg in front of us. Walking, climbing stairs, or bending down to squat all require activation of the hip flexors. 

Glutes, hamstrings, and quads

While you won’t be building much leg muscles with the flutter kick, they’re still engaged to an extent.

  • The quadriceps or quads for short, function to extend the knee or move your leg from bent to straight. It’s also the strongest leg muscle.
  • The hamstrings are responsible for knee flexion and hip extension. 
  • The glutes or butt muscles extend and abduct (move outward), as well as internally and externally rotate the hips. It also supports the knee when in full extension. 

How To Do Flutter Kicks For Core and Conditioning

You might be thinking that there’s nothing much to this exercise. But you’d be surprised that it involves a lot more strategy than just lying on your back and moving your legs up and down next to each other. However, it’s not that simple and you need to know how to do it right otherwise it’s useless and dangerous.

Here’s a step-by-step on how to do the most basic version of this bodyweight exercise. You might need an exercise mat if you don’t want to lie on a hard surface. 

  1. Lie on your back and place your arms down by your sides. 
  2. With both legs together and straight, raise them up to where your feet are almost facing the ceiling. 
  3. Then, lower your legs down and stop before your lower back behind to arch.
  4. Keep your toes pointed to flex the quads. 
  5. Tighten your core and perform the exercise by moving your legs up and down using a range of motion that’s comfortable for you. Your back should always remain flat on the floor. 

Alternatively, some people might place their hands or fists under their butt or lower back to prevent the arching. This can work too as long as you feel it in the abs and not in the hip flexors and lower back. Just make sure your back is completely straight. You can use a mirror to make sure your form is correct if you have one. 

Also, you can lift your head to engage the upper abdominals but again, don’t compromise your technique. 

Crucial form tips

The way that many people perform flutter kicks is a recipe for lower back pain.

As explained in the video above, they’ll lie on their back, hold their legs up a few inches from the ground and begin to flutter away. However, from the example shown, this creates a big arch in the lower back. 

As a result, the hip flexors are the dominant mover as opposed to the core muscles which is not a good thing. The psoas muscle, which is one of the hip flexors, pulls on the spine, therefore, causing some real discomfort. Not to mention, your hip flexors will become tight which can lead to back and posture problems. 

So by keeping the back flat, the core muscles are fully engaged and ready to maintain this position against any movement of the legs that don’t cause the lower back to arch.


Because this is a great core and conditioning exercise, you can do multiple sets. As far as reps go, the flutter kick is commonly performed in a four-count fashion. 

So, for example, you’ll do 1, 2, 3… 1 rep… 1, 2, 3… 2 reps… 1, 2, 3… 3 reps, and so on. Four total leg movements equal one repetition and you’ll never stop moving your legs through the exercise. 

Although counting reps is fine, it’s also a good idea to just perform the exercise to failure. This will ensure you’re really challenging the muscles to create an adaptation due to the stress being placed on the core muscles. Start by lifting one left and try to end the set with the opposite leg if possible. 

You can also set a timer and do intervals. For example, you’ll do 30-second flutter kicks followed by 10-15 seconds of rest and repeat. 

Here’s a video example of the four-count flutter kick…

8 Benefits of Doing Flutter Kicks

There are some surprisingly good benefits to this simple exercise.

Stronger core

A decently strong core is great for several reasons. It protects your lower back from straining whether lifting weights, doing basic activities, or just walking for long hours at a time.

Stronger Core

Not to mention, your core is like a bridge that connects your lower and upper body. And in order to cross that bridge from either direction, well, you need that bridge to be able to support the demands that are placed upon it.

The act of crossing the bridge could be thought of as how the kinetic chain works. According to an article published by the American Council On Exercise (ACE), the kinetic chain can be described as interrelated groups of body segments, connecting joints, and muscles working together to perform movements and the portion of the spine to which they connect.

So for example, when you perform a deadlift, the movement starts from the feet, and then the core must engage even more to maintain rigidity and a neutral spine for the upper body to be able to finish into full extension. 

Better looking abs 

Who wouldn’t want to have a nice-looking set of abs? It adds to the overall visual appeal of a fit body and you’ll definitely like what you see in the mirror. Flutter kicks can help improve the muscularity of your midsection and may even be beneficial for emphasizing your lower abs. 

Crossfit Abs

Improves conditioning

Flutter kicks are a good conditioning exercise that’ll raise your heart rate, therefore, improving your cardiovascular endurance and making you a better athlete or physically fit individual. There’s nothing wrong with wanting to get stronger and build muscle. But if you can be active without gassing out after a minute of activity, then you might want to rethink your current lifestyle.

Burns more calories

If you can build and strengthen your abs while burning calories and preserving your joints in the process, then why not?

Flutter kicks require no gym membership and you can vary the tempo based on your goals. If you want to just work on the abs, a slower pace is ideal. But if you want to still engage the core and burn off those brownies that you just ate (but maybe shouldn’t have), then speed it up and increase the motion of your kicks. 

It probably can’t effectively replace your total-body cardio or HIIT workouts if you want some serious fat-burning action. But it can actually be an effective addition to your training and/or an exercise you do when you have some extra time.

Increases flexibility

Maybe you’re not as stiff as the Tin Man from the Wizard of Oz, but your level of flexibility might not be too far off. Flutter kicks are a great exercise to get you acquainted with developing or improving flexibility. Many are only focused on the weight training and cardio aspect of fitness.

But simple exercise like these that only require your body weight can go a long way in helping you to become more limber. And you might also find that possibly struggling to keep your legs straight and raised off the ground is the motivation you need to start stretching.

As a result, you’ll be less prone to injuries and Better able to complete certain tasks that you struggled with before.

Great warm-up on leg day

Before you do heavy squats, leg presses, or anything else, it’s always a good idea to warm up with a movement that’ll activate the muscles involved. Flutter kicks are great for warming up the core, hip flexors, glutes, hamstrings, and quads, before moving on to you’re main lifts. This will help you to better engage these muscles during the actual movements. 

Awesome finisher

After you’ve trained the main muscles of your workout, you can end with some flutter kicks to burn some additional calories and/or get some core activation in there. It’s good for completely burning out at the end of a session of which it always feels good to go home knowing you pushed yourself to the limit. 

Perfect addition to circuit training session

Circuit training is essentially choosing multiple exercises and moving from one to the other without little to no rest in between. The purpose is to create variety, get a lot done in a small time frame, build endurance, and also build/condition your muscles.

You can include flutter kicks in these workouts as a low-impact, option that has the benefits we previously discussed. 

Flutter Kicks Variations

You already learned how to do flutter kicks. So now, you can introduce some variations that can actually increase the effectiveness of the exercise.

Bent-leg flutter kicks 

Can’t do the straight-leg or basic flutter kick, bend your knees a little to decrease the difficulty of the exercise. This variation could also further reduce the strain on your lower back especially if you have a weaker core. This is a great option for beginners and as a progression into the straight-leg version. 

Arms raised flutter kicks

This is the more advanced variation to the basic flutter kick but it’s not as difficult as some of the other variations we’ve provided. With your arms raised in the air and head lifted off the ground, you require even more engagement of the core muscles which provides a bigger challenge overall. Just make sure to follow the same form tips, keeping your lower back flat on the ground and legs higher up. 

L-sit flutter kicks 

If you’re really advanced and have some decent strength, you can do the L-sit flutter kick. Now, there are a few different variations that you can do. You can either do the basic variation without the use of any tools or, you can use kettlebells, parallettes, or anything similar that’ll allow you to further elevate your body off the floor.

The higher you can lift your body off the floor, the better your range of motion. 

To do it:

  1. Sit on your butt with legs extended on the floor and place your hands down by your sides (palms down) with your arms extended.
  2. Push into the ground with your palms to lift your legs into the air a few inches off the floor while hinging forward at your hips forward to maintain balance. Keep your core tight. 
  3. Move your legs up and down past each other.

V-sit flutter kicks

These are also a bit more challenging as your upper body is lifted off the ground. But the benefit here is that you’re strengthening all of the trunk muscles even more than the basic variation. 

You’ll basically sit up and form a ‘V’ with your upper and lower body. The exercise is still performed the same but you want to make sure to keep your back straight. The height of the legs isn’t as important here as the lower back isn’t is not as vulnerable position. 

If you can’t do this exercise safely and effectively, then skip it and do the other variations until you develop enough strength to move on to more challenging variations. 

On the other hand, if you feel like you need an even bigger challenge, hold a medicine ball in front of your chest in this position. 

Banded flutter kicks

Want to really fire up your glutes, hamstrings, quads, and core muscles, try out the banded flutter kick. It’s essentially the same movement but with bands wrapped around your ankles. You’ll definitely be challenged a little more while likely hitting failure a little sooner.

Wrapping Up

Now that you’ve learned how to do flutter kicks, it’s time to try them out. Or maybe you already do them but want to better your form or get some ideas for effective variations. Flutter kicks are an effective all-around bodyweight exercise that only requires you and the floor so there are no excuses here. 

Do them how you want but just make sure to give some good effort because that’s when you see the best results!


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