Front Crawl / Freestyle Swimming Technique: The Flutter Kick

The flutter kick is a simple and efficient kick used in the front crawl /freestyle stroke, but also in backstroke. Basically, both legs are kept parallel, fairly straight, and quickly flutter up and down with toes pointed.

Underwater shot focused on the flutter kick of a front crawl swimmer

This article explains the technique of the flutter kick as it is used in the front crawl stroke.

We also discuss the following topics:

  • Kicking rhythms.
  • The amount of propulsion generated by the legs.
  • The stabilizing role of the kick.
  • Common mistakes.
  • A few additional tips to improve your technique.

Swimming Technique

Let us now go into more detail about the technique of the flutter kick. Here’s a short video by Mark Durnford demonstrating the flutter kick:

Front Crawl Legs – 6 beat kick

The legs are always kept parallel and move in opposite directions: As one leg moves downwards, the other moves upwards and vice versa.

Downbeat

In the first half of the downbeat, the downward movement is initiated by a slight flexion of the leg at the hip.

Shortly thereafter, the knee also bends a little. The foot goes into plantar flexion (where the toes are pointed), both by muscle contraction and by the pressure of the water against the foot as it moves downwards.

During this phase, the upper side of the foot is downwards and a little backwards. For this reason, while the foot is moving downwards, some water is pushed back. This is how the propulsion is created in the flutter kick.

In the second half of the downbeat, the hip is locked in place while the knee stretches. The toes are still pointed. This phase isn’t propulsive but prepares the leg for its upward movement.

Upbeat

The upward movement of the leg begins while the knee is still stretching. As the thigh moves upwards, the pressure of the water against the lower leg causes the leg to straighten.

The pressure of the water on the ball of the foot and the toes brings the foot in a neutral intermediate position. This phase of the flutter kick is not propulsive either.

Kicking Rhythms

The two most common front crawl kicking rhythms are the two-beat kick and the six-beat kick. There are also less common four-beat kick variations, but they will not be discussed here.

Two-Beat Kick

In the two-beat kick you kick once per stroke cycle with each leg. The downbeat of the right leg occurs during the propulsive phase of the right arm stroke (during the insweep and upsweep phases, to be more precise).

Freestyle two-beat kick

A front crawl swimmer using a two-beat flutter kick

The two-beat rhythm is used by lots of middle and long distance swimmers because it uses less energy than the six-beat kick.

Six-Beat Kick

In the six-beat kick, each leg kicks three times per stroke cycle, that is, a total of six kicks for both legs.

For example, if we concentrate only on the movements of the right arm and leg, the timing of these kicks is as follows:

1) The first downbeat of the leg occurs while the arm extends forward under water.

2) The second downbeat of the leg takes place during the upsweep of the arm.

3) The third downbeat of the leg occurs during the recovery of the arm.

The same timing can be observed between the left arm and leg.

Ian Thorpe Underwater

Ian Thorpe using a six-beat kick during his 400m freestyle world record swim at the 2002 Commonwealth Games.

The six-stroke is almost always used by short-distance swimmers, but can also be observed at times with medium-distance swimmers and long-distance swimmers, but then with a somewhat subdued kick.

Contribution of the Flutter Kick to Propulsion

The main role of the legs in the front crawl is to generate propulsion. Indeed, it is common knowledge that world-class swimmers have a powerful kick (often made possible by large feet).

From this we can conclude that a strong flutter kick is an important prerequisite for fast swimming. But how much do the legs contribute to the overall propulsion?

Well, it’s less than generally thought. Studies have shown that in elite swimmers, the legs only contribute about 10% of the propulsion. The lion’s share of the propulsion is generated by the arms, at least in front crawl.

Stabilization of Body by the Kick

The secondary role of the flutter kick is to stabilize the body.

This is because the movements of the arms and legs compensate each other so that the body does not roll sideways.

In fact, the beginning of the propulsive phase of the arm stroke on one side always coincides with a downward movement of the leg on the same side, which prevents the body from rolling.

Common Mistakes

There are some common mistakes in the flutter kick that affect its efficiency and should therefore be avoided:

Using a Large Kick

A large kick requires more power and also increases drag and therefore should be avoided.

To reduce drag to a minimum, the kick should remain in the shadow of the body moving forward. Ideally, the kick should break through the surface of the water only slightly, and should not move below the line of the body.

The best way to describe the flutter kick is to make fast, compact up and down movements which are initiated by the hip.

Using a Bicycle Kick

If you bend your knees too much while flutter kicking, it will look at little as if you were riding a bike.

The problem with this is that the back of your lower leg moves forwards and not upwards. The water is then pushed forward and slows it you down.

Instead, the kick should be initiated by slightly bending the hip during downbeat. The knee will then follow accordingly and bend only slightly.

Using Too Much Power During the Upbeat

In the front crawl stroke, the upbeat phase of the kick isn’t propulsive. Therefore, you should only use just enough energy during the upbeat to move your leg upwards, but not more.

Bending Your Knees and Pointing Your Toes during the Upbeat

These two mistakes are closely related to the previous one.

If you put too much force into the kick during the upbeat, you’ll also be prone to bend your knees and point your toes, which wastes energy and increases drag.

If you relax your legs during the upbeat, they water pressure will straighten them without you having to drive the movement.

Additional Tips

1) If you have stiff ankles, as is often the case with runners, it can be difficult for you to point your feet back. Your feet will probably be pointing down and maybe even a little forward.

If this is the case, your kick may not provide much propulsion or no propulsion at all. To correct this, you can use swimming fins and stretch your ankles regularly to improve their flexibility.

2) If you want to learn the flutter kick on its own, as a prerequisite for learning the front crawl, the following article proposes a set of drills to learn the flutter kick in a prone position (i.e. floating face down).

3) If you want to improve the efficiency of your flutter kick, vertical kicking can be a welcome alternative to the often performed kicking sets with a kickboard.

Related Pages

You may also be interested in the following articles that cover the front crawl’s swimming technique:

40 thoughts on “Front Crawl / Freestyle Swimming Technique: The Flutter Kick”

  1. Avatar

    In the six-beat kick, when is the third and last kick of both legs occurring?

    Thanks for all the wonderful explanations and work that you are doing with your website.

    Very, very helpful!

  2. Avatar

    I’m learning to swim.

    I mostly do the 2 beat flutter kick.

    Whenever I try the 6 beat flutter kick I get confused and can’t synchronize hand and leg motions.

    Completing 3 leg cycles while doing 1 hand cycle is proving to be a bit hard for me…

    Are there any drills to solve these problems?

    1. Christophe

      Hi Naveen,

      I wouldn’t be too concerned about the six-beat kick, just be patient. Once the other aspects of your stroke are firm in place and working well together, the six-beat kick will come to you naturally.

      Just think kicking harder and faster when you want to swim fast, and there will be an “aha” moment where your body will do the right thing and the six-beat kick will occur naturally.

  3. Avatar
    Mboniseni Simelane

    I struggle with floating and every time I try to float I sink.

    It is worth noting that I am only 3 days into swimming (I did never swim before).

    How can I float without sinking?

    1. Avatar

      Hi,

      I am not a swimming expert or anything but, I read that the positioning of your body, especially at the waist area, is what makes you sink or float.

      And also swimming while facing the wall in front of you.

      You should face down or slightly forward if you can’t face down…

      Hope this helps

  4. Avatar

    On the 1959 Panamerican Games held in Chicago, George Breen used the two kicks in the 1500 freestyle event.

    It was an interesting way to swim those 1500 hundred meters!!!

    After that it was common to see swimmers on that distance, 1500, using that two-beat kick.

  5. Avatar

    Hi, I am currently learning swimming on my own and I encountered few issues I hope you can help me.

    1. I can now float on my back and front. Right now, I can do front crawl but only with arm movements. I have hard time doing side breathing. It seems I cannot rotate my body to the side or I just have bad timing. I know I have to exhale underwater and to breathe every 3 strokes but I just can’t do it. It’s frustrating I have to stop just to breathe. Do you have any suggestions to correct this?

    2. Also I am curious how can other people swim with their heads up? I tried doing the same lifting my shoulder and head up but nothing happens I’m still underwater. I also can’t lift my head up to breathe while doing front float. How do they do that?

    3. As for breaststroke, do I lift my upper back or just head to breathe? After I breathe, I sink so low in the water. Do you have any tips?

    4. I also tried doing sculling and eggbeater kick but failed. I tried doing sculling while doing back float but nothing happens as for eggbeater kick I just go backwards. Do you have any idea why?

    Please help me, I really appreciate your help. Thank you!

    1. Christophe

      Hi Soph,

      1. I’d suggest you practice the series of drills from the “Learning the Front Crawl” section of this website. You’ll learn horizontal balance, body rotation and breathing on your side in those drills.

      2. Do you mean lifting your head forward while swimming front crawl, to see above the water surface?

      If that’s the case, you need to push both down and backward at the beginning of the underwater arm stroke. But it requires good coordination and technique.

      Also, when I do this, I only lift my head up so as that my eyes are above the water surface. My mouth stays below the water surface. I still breathe on the side.

      If you lift your head forward to breathe, your lower body will sink, so you need to inhale quickly, and then quickly release your upper body in the water so that your lower body floats up again.

      3. To breathe in breaststroke, you should keep your head in line with your torso. Your head, shoulders, and upper chest should rise above the water surface as a unit as you breathe, and then drop back into the water.

      4. I’m sorry, I have to admit that I never learned to do the eggbeater kick. I wanted to learn it a few years ago but had to stop because of knee problems.

      1. Avatar

        1. Okay, thanks for your suggestion I’ll take a look at it.

        2. Yes, actually not just front crawl. I also saw others doing it with head up breaststroke and also when doing front float they push water down to breathe.

        I can’t do any of that. I just can’t lift my head. Well, I can but just less than a second is that really like that? There’s not enough time for me to breathe. I take a deep breath then exhale while entering the water until going up for air. Is this wrong?

        “I only lift my head up so as that my eyes are above the water surface. My mouth stays below the water surface. I still breathe on the side.”

        I thought doing this makes breathing easier, but it seems it’s just the same as normal freestyle, right?

        3. Is it possible to breathe in 1 sec? It seems the major problem for me is breathing. I have no idea how to fix this. I hope you can explain more in detail on how much you breathe in and out maybe using percentage or something you prefer.

        Thank you!

        1. Christophe

          Hi Soph,

          2. Breathing in breaststroke (and front float) is more a matter of bending your knees so that your legs drop and your body pivots around the hips. Then you head, shoulder, and chest will move up and you can breathe.

          In front crawl, you normally breathe on the side. I thought you were referring to the case where you are swimming front crawl and want to look forward (for example in triathlon races).

          3. I think in front crawl, it takes me less than one second to inhale. In breaststroke, it could take two seconds. The important thing to know is that you must exhale underwater. Then it’s possible to quickly inhale above water.

  6. Avatar
    Charlotte de Clerck

    Hello,

    I’ve been learning for a month now, but I still can’t do the kicking properly as I tend to kick as fast as I can without even caring about the beat…

    I’ve been trying to do the 2-beat kick but I keep on sinking instead of moving forward, and I can’t do the breathing properly without a perfect kick…

    Do you have any tips for this problem?

    1. Christophe

      I guess you are lacking horizontal balance. You then need to kick hard to avoid sinking, which quickly uses up your oxygen and makes it impossible to breathe properly as you get out of breath quickly.

      Please practice the sequence of drills in the front crawl section:

      http://www.enjoy-swimming.com/learn-how-to-swim.html

      This will let you practice balance, rotation, breathing on the side, coordination of the arms, kicking etc.

      Take your time, don’t rush the process.

  7. Avatar

    It seems that whole leg movement/flutter kick contributes (at the best) only “a little bit” to propulsion (during the first half of downkick). Am I correct?

  8. Avatar

    Why do professional swimmers not adopt the “frog kick”?

    It can contribute significantly to propulsion (> 50%?), that can possibly overcome some negative effect on “streamline”.

    I have tried it myself. It is faster than using a flutter kick.

    I don’t know why it is not popular.

    1. Christophe

      Hi Chang,

      The frog kick creates tremendous propulsion during the active phase, but also a lot of drag during the recovery, which on average is less effective than the flutter kick.

  9. Avatar

    Hi.

    I want to thank you guys for your kind efforts in teaching us the techniques of swimming.

    I did not know how to flutter kick at all. It took me like ten sessions to get the idea of what had to do with my legs! But, I got it at last.

    And thanks to lots of practice, I can now flutter kick like a steamboat! In fact, I am now swimming the crawl.

    God bless you.

  10. Avatar

    When I swim, I kick too much, and I think because of that I get too tired.

    I make small little fast kicks. I want to kick slower.

    Someone told me to train my stroke with a pull boy in the legs.

    Is this correct?

    1. Christophe

      This most likely is a balance problem.

      You are using the kick to keep your legs up instead of using them for propulsion, and that’s why you get tired, as you suspected.

      Our front crawl drills take care of this and teach you how to use balance to keep your legs up.

      The head-lead front balance drill is especially useful to correct this problem.

  11. Avatar

    Hi,

    I am learning to swim.

    While doing Forward Crawling, I can do decent kicks. I can do very fast or normal also.

    But the problem comes with front crawl. I don’t know, but the moment I move my first hand, the legs will stop moving at all.

    I can still swim and complete the distance, but it becomes a struggle by the end.

    Also, when I breathe, the body goes down a bit, and if I am not able to do the kicking, then it doesn’t come up.

    I am getting very desperate about it…

    At times I try too hard, but they get so stiff then… Sometimes I launch myself just focusing on legs and ensure that no matter what, I will keep kicking and at that time, the kicks will start vibrating.

    So I am finding it very hard to get the hand and kick coordination.

    Also, every day when I go to the pool, I try motivating myself that that day it will happen, but, that’s not happening at all.

    I need your advice and some tips/drills which will help me with this.

    Thanks and Regards,

    Adnan

  12. Avatar

    Thank you very much for the highly informative website.

    I am a 54-year-old male.

    I am not fatty and have been learning swimming for the last 20 days.

    My problem is with kicking. My legs always go down after a few kicks.

    If I am getting slight support under my hips, I can kick efficiently.

    I am quietly confident that if I can correct this hip sinking issue, I can swim smooth.

    Please help.

    1. Christophe

      Hi Saleel,

      The following front crawl drill took care of this issue for me.

      Once you understand how sinking legs are linked to an incorrect upper body position, and you learn how to correct this problem, sinking legs should be a thing of the past.

  13. Avatar

    Hi Christophe,

    Thanks for the great article.

    I have a problem with kicking too much out of the water in both backstroke and front crawl.

    Would be very grateful for any tips/alterations I can make to improve this.

    Dan

    1. Christophe

      Hi Dan,

      I think that generally, doing regular kicking sets with short blade fins (and a swimmer’s snorkel) can help. Vertical kicking sets can also help.

      In front crawl, using a six-beat kick instead of using a two-beat kick also should help reduce the kick’s amplitude.

      Finally, if you have stiff ankles, doing some ankle stretching exercises on a regular basis (without overdoing it, please don’t injure yourself) should increase the efficiency of your kick and hence decrease the need for a wide ample kick.

      By the way, doing kicking sets with short blade fins also helps improve ankle flexibility.

      Hope this helps,

      Christophe

  14. Avatar
    Alexey Filippov

    Is this statement in “Swim Stroke Phases” section correct?

    Synchronization between arms and legs

    The timing between arm stroke and leg kick is also very precise.

    Whether you use a two beat kick or a six-beat kick, the downsweep of the propulsive arm and the downbeat of the leg on the same side always starts simultaneously.

  15. Avatar

    Hi.

    I am new to lap swimming.

    I am struggling to make progress because I have to stop after each length of the pool to catch my breath (I am in decent shape overall, so this is more of a swimming problem than a general fitness issue.)

    This makes it very difficult to improve my stroke, because I am so focused on trying to side-breathe that I can’t focus very much on my mechanics.

    And because my mechanics are not great, I have to expend a lot of extra energy, which makes breathing that much harder.

    Would you recommend using a snorkel at first so I can focus on my stroke, then once I have improved and built some stamina, add side breathing as the “finishing touch?”

    In other words, do you think it is a good idea to isolate the breathing from the stroke itself at first?

    Any feedback would be appreciated.

    Thanks.

    1. Christophe

      Hi Brent,

      This is a common problem because you need to do a lot of things simultaneously while swimming front crawl.

      A snorkel can certainly help you to concentrate on your arm and leg movements without having to bother with breathing and so is a nice tool to have in your bag.

      However, to get really comfortable in the water, you need to be able to balance your body in a horizontal position and you also need to be able to roll from the side onto your stomach and back on the side effortlessly.

      Once you can float on the side and stay balanced, breathing really becomes a non-issue and everything else becomes a lot easier.

      The best way to learn this is to follow the drill progression in the “Learn the Front Crawl” section of this site: http://www.enjoy-swimming.com/learn-how-to-swim.html

      It will take a few weeks to go through these drills but you will save yourself a lot of hassle and struggle in the long run if you go through those exercises.

      Good luck!

  16. Avatar

    This is actually a great site for info and tips, Thanks.

    I was forced to start swimming 6 months ago when I had a spine op. Slowly warming up to it, haha.

    I feel like my form is decent, the lower body stays up, ankles are pretty flexible etc, but I noticed my leg propulsion is still pretty terrible when I look at other swimmers.

    I try a few one hundred meter kickboard drills and using fins but don’t seem to be getting faster.

    It literally takes me a whole minute for 25 meters with the kickboard. Any advice?

    My overall swim speed has improved but it seems to be all arm propulsion. Thanks

    1. Christophe

      Well, I have to tell you a secret, I suck at kickboard kicking too, ha ha. I rarely do kicking laps with a kickboard.

      When I want to work out my legs I prefer to put on a swim snorkel and extend my arms forward and then I can kick very hard and also get all the air that I need to do several laps.

      But I also prefer to work on my technique rather than to do kicking sets for my legs, so I don’t do them that often.

      I also have observed that girls often have an easier time doing kicking sets with a kickboard, they seems to have a different balance in the water than men.

  17. Avatar

    Hi,

    I’ve been on a swim team for about 4 years and I’ve always had trouble with the flutter kick.

    It always causes pain in my knees and no matter how fast I kick or how hard I try I don’t seem to be going anywhere when using kickboard.

    when I talk about my knees hurting people tell me to use my hips and not just bent my knees but they still hurt when I do that.

    I feel like there is something I could do to kick faster and with less pain but nothing works.

    Please help!

    1. Christophe

      Hi Nikki,

      I’d really recommend you see a physician or physical therapist, your knees shouldn’t hurt while flutter kicking! Don’t ruin your knees!

      In addition, some people are good kickers and some are weak kickers.

      Anyway, there are no kickboard kicking competitions, so being weak kicking a kickboard doesn’t necessarily mean you’ll be a weak swimmer.

      But please get your knees checked out.

  18. Avatar

    Hi Chris.

    Thank you for the effort in writing such articles. You are a lifesaver.

    I began my first lesson for the 1st time ever yesterday and the next is tomorrow… That is, I will be practicing 2 days per week for an hour.

    I am glad to know that I can float, kick but of course not for propulsion as yet… But reading your articles I will get there.

    I just want to know… How long will it take for me to be a good swimmer? Estimated time roughly?

    1. Christophe

      Hi Londwie, thanks for the kind words!

      It is great that you are starting swimming lessons!

      As for your question, it depends on what you call a good swimmer.

      If you are dedicated, you can make a lot of progress in a few months of time and become reasonably proficient in a few of the swim strokes.

      Good luck and have fun!

  19. Avatar

    I am a beginner and I really want to know how to keep my toes in a proper position while kicking…

    It is really getting very hard for me…

    Please help.

    1. Christophe

      Hi Siya,

      I’d suggest you use short swim fins for a while. They will teach you a proper foot and toe position while kicking.

      Good luck

  20. Avatar

    I have been trying to learn to swim for a while now and have had swimming lessons as well but whenever I try to do the front crawl I panic when breathing and have to stand up in the pool to take a breath.

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