The Flutter Kick: Swimming Technique and Common Mistakes

This article describes the technique of the flutter kick in the front crawl stroke. It also covers common mistakes, kicking rhythms and some tips to improve your technique.

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

To get started, let’s have a look at a video that shows the freestyle kick in action during the men’s 1500 final at the 2004 Olympics:

Video Thumbnail

As you can see in the swimming video above, the flutter kick is a simple and efficient kick used while swimming freestyle. Basically, both legs are kept parallel and quickly flutter up and down with toes pointed.

Flutter Kick Roles

1) The first role of the flutter kick is to provide propulsion. It is a fact that world-class swimmers have a powerful kick. So it is clear that the kick has its importance in fast swimming.

However, it might be less than you think. In fact, studies have shown that the amount of propulsion provided by the kick in elite swimmers is only about 10%. The rest of the propulsion is provided by the arm stroke.

2) The second role of the flutter kick is to stabilize the body. In fact, the start of the propulsive phase of the arm stroke always coincides with a downward motion of the leg on the same side.

Swimming Technique

Let’s now cover the flutter kick technique in more detail.

The legs are kept parallel at all times and execute opposite movements: while one leg kicks downward the other one moves upward, and vice versa.

1) During the first half of the downbeat, the downward movement is initiated by slightly flexing the leg at the hip.

Shortly after, the knee also bends a little bit. The foot goes in plantar flexion (toes pointed), both by muscle contraction and by the pressure of the water against the foot as it moves downward.

During that phase, the top of the foot is oriented downward and a little bit backward. Because of this, while the foot moves down some water is in fact pushed back. That’s how propulsion is generated in the flutter kick.

2) During the second half of the downbeat, the hip is locked in place while the knee is extended. The toes are still pointed.

This phase isn’t propulsive but prepares the leg for its upward movement.

3) The upbeat movement of the leg starts while the knee is still extending. In fact, while the leg moves upward, the pressure of the water against the lower leg will straighten it.

The pressure of the water against the bottom of the foot will also move it in an intermediary neutral position. This phase of the flutter kick isn’t propulsive either.

Kicking Rhythms

There are two popular kicking rhythms in the freestyle stroke, the two-beat kick and the six-beat kick.

Two-Beat Kick

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

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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.

Let’s consider the movements of the right arm and the right leg:

1) The first downbeat of the leg occurs during the forward extension of the arm.

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

3) The third downbeat of the leg occurs during the recovery of the arm. The left leg moves in opposition to the right leg.

Video Thumbnail

The six-beat kick is nearly always used by short-distance swimmers but is also popular with middle distance swimmers and long distance swimmers but with a somewhat subdued kick.

Common Mistakes

There are a few common mistakes in the flutter kick that decrease its efficiency and hence should be avoided:

1) Large kick: to keep drag to a minimum, the kick should stay within the hole opened in the water by the head and trunk while moving forward.

Ideally, the kick should neither break the water surface nor move below the line of the body.

2) Bicycle kick: during the downbeat, the kick is initiated by slightly flexing the hip, and then the knee follows suit, also only bending a little bit.

If you do bend the knee too much, the back of your lower leg will, in fact, move forward rather than upward. Water will then be pushed forward and slow you down.

3) Putting too much force in the kick during the upbeat: in the freestyle stroke, the upbeat phase of the kick isn’t propulsive. So ideally you should relax your leg during the upbeat to save energy.

4) Bending your knee 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 have the tendency to bend your knee and point your toes, which wastes energy and increases drag.

Ideally, you should relax your leg so that the water pressure will extend it during the upbeat.

Additional Tips

1) If you have stiff ankles, it might be that your foot is pointed downward or even downward and forward during the first phase of the downbeat.

If that’s the case, your kick might provide no propulsion at all or even tend to move you backward rather than forward. This often occurs in people that have a running background.

Using swimming fins and regularly stretching can improve the flexibility of your ankles.

2) We have swimming exercises to learn how to flutter kick and balance in a prone position.

3) An excellent exercise to improve your kick is vertical kicking.

39 thoughts on “The Flutter Kick: Swimming Technique and Common Mistakes”

  1. tiberiusemail

    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. Naveen Paudel

    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. 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. 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. 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. 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. 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 freestyle 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. Hi Soph,

      1. I’d suggest you practice the sequence of drills in the “Learn the Freestyle Stroke” 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 in front float 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. 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. 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 refering to the case where you are swimming front crawl and want to look forward (for example in triathlon races).

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

  6. 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. 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 freestyle section:

      https://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. 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. 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. 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. 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. 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?

  11. 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 freestyle. 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 with 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. 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.

  13. Hi Christophe,

    Thanks for the great article.

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

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

    Dan

    1. 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 freestyle, 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. 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. 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. 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 rally 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 Freestyle Stroke” section of this site: https://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 on the long run if you go through those exercises.

      Good luck!

  16. 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. 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. 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. 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. 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. 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. 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. 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

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