Swim Training: Rethink Rotation in Backstroke and Freestyle

  31 SwimSwam | December 14th, 2016 | International, Opinion, Training, Training Intel

Courtesy of Gary Hall Sr., 10-time World Record Holder, 3-time Olympian, 1976 Olympic Games US Flagbearer and The Race Club co-founder.

Propulsive Forces & Frontal Drag Forces

Sir Isaac Newton’s three laws of motion are as applicable today to a swimmer as they were centuries ago when he formulated them. However, for me it is easier to conceptualize the application of the three laws by separately considering the forces that move us through the water (propulsive forces), the forces that slow us down (frontal drag forces) and the law of inertia, which tells us it is most efficient to maintain a constant speed by keeping the forces of propulsion and drag equal.

Axial Rotation

The propulsion of a swimmer is derived primarily from two sources, the hands and the feet. However, there is another motion involved in the freestyle and backstroke of a fast swimmer, other than kicking and pulling, that is vitally important to generate more propulsion; the axial rotation of the body from side to side.

Freestyle & Backstroke

Although coaches and swimmers commonly believe that one of the reasons fast freestlyers and backstrokers rotate their bodies along the axis of their motion is to reduce drag, I don’t agree. If that were true, we would see a substantially faster kicking speed on our sides than we do on our stomachs or backs, and that is simply not the case.

Another common theory for why we rotate our bodies in freestyle and backstroke is so we can reach out further on each stroke. While that may be true at the finish of a race (particularly freestyle), I don’t believe the extension of the arms on the recovery of a rotating swimmer is any further than on a non-rotating swimmer.

Mechanical & Biomechanical

There are two reasons for rotating the body during freestyle and backstroke. One is mechanical and the other is biomechanical. The biomechanical reason is that by rotating our body to initiate the underwater pull, we put ourselves into a more favorable position to use our back muscles, particularly the large latissimus dorsi muscle. That will make our pull stronger.

The mechanical reason is that by counter-rotating our bodies during the underwater pull we can create a significant force to pull against. In other words, we are no longer pulling against just water molecules that are relatively motionless. We now have the water, plus whatever force we can generate with the counter-rotation of our body. The amount of that force that we get to pull against is related to our mass (weight) and to the angular velocity of our body’s rotation (how fast we rotate).

The rotation of the body doesn’t just happen. A swimmer has to make it happen and that requires a lot of core strength and work. When the rotation is fast and timed well, it is worth the effort, creating a substantial force that enable the swimmer to cover more distance with each stroke.

No one said swimming fast was easy. Here are some of our favorite drills:


Gary Hall, Sr., Technical Director and Head Coach of The Race Club (courtesy of TRC)

Gary Hall, Sr., Technical Director and Head Coach of The Race Club (courtesy of TRC)

Yours in Swimming,
Gary Hall Sr.





[email protected] <http:[email protected]

Www.theraceclub.com <http://Www.theraceclub.com


The Race Club, logoThe Race Club, logoBecause Life is Worth Swimming, our mission is to promote swimming through sport, lifelong enjoyment, and good health benefits. Our objective is for each member of and each participant in The Race Club to improve his or her swimming performances, health, and self-esteem through our educational programs, services and creativity. We strive to help each member of The Race Club overcome challenges and reach his or her individual life goals.

The Race Club provides facilities, coaching, training, technical instruction, video, fitness and health programs for swimmers of all ages and abilities. Race Club swim camps are designed and tailored to satisfy each swimmer’s needs, whether one is trying to reach the Olympic Games or simply improve one’s fitness. Our programs are suitable for beginner swimmers, pleasure swimmers, fitness swimmers, USA swimming or YMCA swimmers, or triathletes; anyone who wants to improve swimming skills. All of our Race Club members share an enjoyment of being in the water and use swimming to stimulate a more active mind and body.


  1. Buster says:

    I’ve never agreed with the view that you get more reach at the finish by rotating. Yes, it’s a good way to get kids to reach out for the finish but in actual fact the position of your body is purely down to the perspective of the viewer. I’ve seen so many coaches on poolside reaching up and then showing “how much further they can reach when they turn side ways”. Well, like I say it all depends on where you’re looking at them from.

  2. Dafecat says:

    When you rotate, you get more reach which results in more glide and more power through the stroke.

  3. Michael Burrows says:

    Reach vs Pull
    Hi Gary, love your articles.
    I teach kids swimming and am attempting to establish ‘my teaching philosophy’ on these sometimes conflicting areas. Your thoughts or information most appreciated.
    ‘which tells us it is most efficient to maintain a constant speed by keeping the forces of propulsion and drag equal’


    Reading, looking, trying………ha will never everything…..BUT would like to attain a standard of excellence for my swimmers.


  4. Pau Hana says:

    “Although coaches and swimmers commonly believe that one of the reasons fast freestlyers and backstrokers rotate their bodies along the axis of their motion is to reduce drag, I don’t agree”

    I’ve never heard any coach claim that rotation is intended to reduce drag. Is this a common belief? When I started coaching I was taught that it was to increase propulsion. The headline seems to allege that this is a radical theory, when in fact it’s fairly common knowledge in my experience.

    • gary Hall says:

      In my experience, coaches often tell swimmers to do the right thing…but for the wrong reason. Body rotation is a good example. I have heard many coaches and swimmers state that body rotation should be done to reduce frontal drag…but not to augment propulsion. It sounds like you had a good teacher.

      • Pau Hana says:

        Had a lot of people express this but Bill Boomer was the coach who clearly stated it in a way that carried the most impact and clearly laid out the scientific principals. 🙂

        • gary Hall says:

          The coupling motions we are referring to are extremely common. We use them every day…swinging the arms while walking, rotating the body during a golf swing, moving the legs during the long jump. I just don’t think many people have recognized just how powerful these coupling motions are and how they can augment propulsion and speed. Bill Boomer apparently gets it.

  5. Susan jones says:

    Really enjoying the race club swim drills. As a lead coach at a club for younger to older swimmers I can adapt the drills and being a massive yoga fan too. Glad you agree it goes hand in hand with swimming. Wonderfully presented and great descriptions throughout.

  6. love2swim says:

    Is anyone familiar with the freestyle technique taught in the IKKOS program? I ask this because our team is using IKKOS for stroke technique. It seems the more IKKOS lessons, those swimmers are now swimming a straight arm freestlye, with arms swinging to the sides over the water. To me, it does not look as effective as a traditional stroke.

    I’m curious what is on the video in the IKKOS goggles as I haven’t seen it myself and my swimmer cannot articluate it. Is this program teaching effective stroke technique? Thoughts?


    • gary Hall says:

      There are two important coupling motions in freestyle that increase propulsion. One is body rotation and the other is the arm recovery. The amount of kinetic energy in those two motions is proportional to the square of the angular velocity (speed of the rotation or stroke rate) and the square of the radius. With the arm recovery we can change both angular velocity and radius…yet with the greater mass of the body compared to the arm, its rotational speed is the most important coupling motion.
      With a low swinging straight arm, the kinetic energy of the arm may be high, but body rotational speed is sacrificed. Ideally, one wants both body rotation and high energy arm recovery. That is why sprinters will lengthen their arms and recover more over the top than to the sides. Hope this helps.

      • Swimfan says:

        Very interesting Gary! Can you define “coupling motion”?
        Also, you really have the technical aspects down…just curious how you know all of the technical details – besides your experience of course! 🙂 – what did you major in college or study thereafter, is this Physics or ?? A friend of mine’s father was a professor of sports kiniesology (sp?) with specialty in swimming (he was also an Olympic swimmer long ago) – is this the field? So interesting!

  7. Germanengineer says:

    The mechanical reason Mr. Hall explains and seems to cause some confusion, can be maybe most easily visualized or explained by making a comparison to a bullet. All firearms are nowadays design in a way, that a bullet leaves the barrel spinning.

    This spinning motion does not increase the speed of the bullet, however by creating a centrifugal force it increases the energy of the bullet making it more stable and thus flying further.

    Same applies to the rotating body of a swimmer. The rotation creates a centrifugal force which increases the energy of the moving body. This does NOT however translate automatically into faster swim speed nor does it increase the power of the pull.

    What it does do however, is create the possibility for a stronger stroke. The body provides a force which can be pulled against. Thus the timing of the rotation is critical and has to match the timing of the stroke.

    Anyone who is confused by the the terms centrifugal force or energy of a body, I would recommend to just play around with a spinning top for a while and observe how it behaves and what happens if you try to nudge it at different speeds.

    • DR. EVIL says:

      A great discussion!

      To GermanEngineer – Your explanation is a great one, with “rifling” of a gun barrel and the development of an oblong bullet definitely makes it fly further and generally straight. Using the spinning top analogy is also a good one except I don’t feel that a swimmer is rotating fast enough to create the angular momentum effect of a spinning bullet or a top.
      Consider that the actual propulsive forces generated by the pulling arm are really not that great.

      There have been very many studies old and new that have shown peak pulling forces in freestyle at 80 to 100 newton’s or about 18 – 22 lbs. of force. Not very high. In that case, it would really take significant increases in propulsive force to have a dramatic effect in velocity which are not possible in a non-fixed medium to pull against.

      Consider that it has been shown that swimmers at the surface experience 3 different types of drag. Friction, Pressure, and Wave drag. Everyone logically thinks that friction drag is the major player, but as the body of swimmer at the surface goes faster, in fact, wave drag is the largest contributor by a wide margin to the overall coefficient of drag. But not what most would believe.

      Thinking about the effects of drag, I really don’t believe there is really any momentum created by a rotating body or the weight of the arm recovering over the top because the instant any propulsive force is decrease during the stroke cycle, a swimmer doing freestyle immediately decelerates because the drag (wave) caused by water at the surface is so great. So it’s not really a function of increasing the propulsion (low) that makes swimmers fast, but larger gains are made in the elimination of drag. That is why a deep stroke can create a lot of force, but because of the drag, does not increase velocity.

      I would be really interested in your thoughts….

      • Germanengineer says:

        As Mr. Hall mentioned in his article, the rotation has no or only minimal effect on the drag the body faces. And of course it is always more beneficial trying to decrease drag, as that contributes to the overall efficiency.

        You are right about a deep pull creating more drag than a shallow pull, however the body rotation does not automatically create a deeper pull. It is very well possible to swim with strong rotation and connect it to a high-elbow catch and shallow stroke.

        As to your doubt about the amount of angular momentum created by the rotating body compared to a bullet or a spinning top, you have to take into account that the rotating body of a swimmer has some serious mass compared to the tiny bullet or top.

        The physics behind the forces created by the rotation is a really hard one to fully understand. Maybe it is easier to forget about the potential it offers for increasing the force of the stroke and observe another aspect: stabilizing forces created by the rotation: these are actually the same forces, the only difference being, that stability is easier to observe than force.

        Again the comparison to the bullet applies. A bullet which doesn’t spin will tumble out of control with the smallest amounts of wind. A spinning bullet might alter its path slightly but flies relatively straight, no matter what kind of storm you shoot it in.

        If you want to observe the same effect in swimming, do the following: take some of your swimmers, let them grab the biggest paddles available and let them put a pullboy between their ankles (not the thigh). Let them swim freestyle from a standstill floating position. Once with a body as flat as possible, and once with decent amount of rotation. Observe in which case the body stays more stable.

        Of course there are swimmers with lacking core strength or swimmers who have no experience rotating the body, so results may vary. But all in all the rotating body should be more stable than the flat one.

        A stable body in itself does not increase the power of the stroke. But it gives the possibility to apply more power to said body.

    • big calves says:


    • DLswim says:

      The issue with rifling has to do with conservation of angular momentum. If you add rotation about the long axis of the bullet, with the corresponding angular momentum pointing along the axis (parallel or antiparallel, depending on the sign of the rotation), then small perturbations due to air currents, etc., will have a minimal effect on the direction that the bullet goes, thus increasing accuracy. However, I don’t think in swimming this is relevant because the speeds through the water are so small and the viscosity of the water so large in comparison to the bullet. I also question the idea that rotation can create additional propulsion, unless this causes the water to have a momentum component along the direction of motion, in which case the change in momentum caused by pulling with the arms would cause a larger change in momentum (and thus force) in the forward direction. However, I don’t see how rotating side to side would add momentum to the water molecules in the forward direction; I can believe that it would cause lateral momentum, but this would not increase propulsion in the forward direction.

      I remember a while back that a professor at MIT in mechanical engineering did some fluid dynamics simulations of how an arm pulls through the water, and came to the conclusion that pulling sideways was less effective than pulling straight backwards. I think what is needed is to do a full three-dimensional FD simulation to determine these questions, rather than talking about this in qualitative ways that sometimes don’t make physical sense.

  8. Mike Lyman says:

    I would like to tackle a couple of things that I’ve read here and hopefully break this down into something slightly easier to understand.

    First off, I think Gary Hall Sr. is right about rotation giving us more force (sort of), but first, let’s analyze how we actually go forward in the water in a very simple way.

    In order to go forward, we must push water backwards. It sounds simple, but has complicated components. Start from the bottom up with the kick. We push against the water with the front of our legs at an angle, which has then two components, a downward component and a backwards component (for more on that google vectors). The downward push lifts our legs (the reason why, when done correctly, this kick helps lift the legs and put our bodies into a more horizontal position making us more streamlined). The backwards component pushes water behind us thus moving us forward: mass propelled behind equals motion forward.

    Arms are next. The same principle applies; we must push water behind us in order to move forward. A coach when I was younger always liked to say that we were “anchoring our hands” and then just moving past the anchor to swim. While this is an ideal situation, the reality is that our arms don’t stay in exactly one spot as we move forward since water, although dense, is still fluid and will move slightly behind our pull even in the most perfect of strokes. For a moment, let’s got back to high school physics:

    F=ma (force = mass x acceleration)
    The force we are applying is directly proportional to the mass we push behind us (the water behind our arms) and the acceleration of that mass (the increase of speed from the moment we put our hand in the water [0] to the highest speed our arm obtains during our pull).

    THIS is where Gary’s extra force from rotation comes into play.
    Imagine that you are on your side and stationary with no rotation. You then pull your arm down to your side as fast as you can. You have accelerated your arm with an angular momentum caused by the rotation of your arm about your shoulder. The force behind your arm might be represented like this:

    F = [mass of water] x [acceleration of that water (due to your shoulder)].

    Now, let’s say this time you pull with the same acceleration in your shoulder, but you are now rotating your body as well. Your rotating arm is now on a rotating body, which increases the linear speed of your hand through the water. For simplicity’s sake, it’s like throwing a ball 70 mph while standing still compared to throwing it from a car that is moving 10 mph in the same direction. To you on the car, it would seem the ball is moving at 70 mph, but to the bystander on the side of the road who isn’t moving, it would seem that the ball is moving at 80 mph. Our ball has undergone a greater acceleration. Our new force might be represented by this equation:

    F = [mass of water] x [acceleration due to arm + acceleration due to rotation]

    My physics is a bit rusty, but I am certain that the linear speed of your hand through the water with rotation CAN be faster than without rotation.

    Now, I know what your are thinking here. If more rotating creates more acceleration, then wouldn’t it be better to rotate as much as we can? Why not all the way to vertical? Why are we seeing swimmers go faster with a flatter stroke now than what they used to do in the 90’s (when I was an age group swimmer)?

    The answer here is that we are limited to the power of our bodies. The deeper the pull, the more torque we are faced with and thus the more resistance behind our hands. We need more force to generate the same acceleration of the water even though we are pushing more mass (water). There is a limit to how fast we can move our arms and also rotate our bodies. There is obviously a point of diminishing returns, a happy medium where the rotation of our bodies provides some extra hand speed, but doesn’t put our hand so deep or rotate our body so much as to negatively impact the total force that we need to propel water behind us. We also have to take into account the amount of coordination it would take to rotate that much and also whether or not we could effectively kick in those positions. All of these factors are hard to measure exactly in a practical environment.

    Now to address “Because the deeper pull also creates so much more frontal drag force.”
    I have already explained why a super deep pull may not be beneficial as far as moving faster through the water. While this “drag force” idea goes along with the theme that over rotation may not the be the key to swimming faster, I don’t believe that drag force due to hands plays any part in that. The reason is this:

    In the very best possible scenario, we put our arm in the water, anchor it, then move past it as our arm remains in one fixed location in space. Our arm encounters an initial opposing force as we enter the water, but not as we start to pull. In this scenario, our arm faces NO forward drag because we are simply moving past the water that we are pulling, not running into it. In order for our arm to create negative drag against our movement, our bodies would need to be moving faster through the water than our arms (and thus the water would push against them). While this has been proven to be the case with dolphin kick, where individuals have broken world record swim paces by just kicking underwater, it is not the case with free kick especially at the surface of the water, where a kick would be less efficient. Furthermore, as I mentioned earlier, our arm does NOT perfectly anchor and stay stationary in the water but rather it moves backwards towards our feet slightly. Because of this, drag is not an issue.

    Keep in mind that all of the above are merely musings of a former mechanical engineer turned swim coach. If any of you physics majors out there have a more accurate account of what might be happening here (Michael at Rice Aquatics, time to chime in!) I would love to read them.

    Otherwise I think that the take home note here is that Gary Hall Sr. is right about the rotation causing more force for us to pull with, even if it only benefits us up to a certain point.

    • ML says:

      I think you’re overlooking that different parts of the arm move at different speeds. Your hand may remain stationary in the water, but the higher parts of your arm will be dragging (the higher the part the more the drag).

  9. Clive Rushton says:

    Interesting, isn’t it? It’s 2014 and we really don’t have much idea how swimmers ‘actually’ swim. There are lots of theories (and Gary’s make great reading and have a lot of substance), but no one actually ‘knows’. Sacrilege, eh?

  10. While it is hard to visualize how one creates a force or anchor to pull against using one’s own body, it is true. The rotational motion by itself plays no direct role in propulsion. In fact, the counter-rotation of the body is just one of several energy systems going on while we move down the pool. Another is the recovery of the arm over the water and in shoulder-driven freestyle, the energy of that system also creates a force we can pull against with the opposite hand (not so in hip-driven freestyle, as the arm is already in the water before the other starts the propulsive phase). A third force is generated by the kick and it is not a coincidence that the strongest of the three down kicks that occur during a cycle of a six-beat kicker occurs at the end of the back quadrant propulsive pulling phase, after the counter rotation of the body is completed. I will write more on this later.
    Elite swimmers rotate a lot, but the amount of rotation must be compromised by high stroke rate. The timing is key to make these forces connect.

  11. Canukian says:

    Don’t really want a deeper pull in backstroke. You want that arm in high at the top and the rotation lets you tuck that elbow into the sweet spot so you can get the hand at the right angle (fingers pointing to the lane rope) ASAP. That is what makes for a longer pull. The top-side speed of the rotation gets that pull started fast and the hip snap rotation releases the water at the end of the pull and the cycle continues.

    If you think about the propulsion phase as what happens when you take your flat palm through a pile of snow (sue me, I live in the great white north!) and that pile builds up the longer you keep your hand in the same position, in a straight line, you can sort of translate it to a backstroke pull. Sort of. But it gives a decent picture/

  12. Catherine says:

    Barb, it makes sense to me that rotating to the side would decrease drag but I don’t think that’s what this article is saying.

    Here’s my interpretation:
    One sentence says “The amount of that force that we get to pull against is related to our mass (weight) and to the angular velocity of our body’s rotation (how fast we rotate).” That sentence is talking about a torque, which would be side to side at best and give no propulsion. The previous sentence says “We now have the water, plus whatever force we can generate with the counter-rotation of our body. ” If you believe that, I have a perpetual motion machine I’d like to sell you.

    Sven, thanks for pointing out that the elites don’t rotate much these days. Back in the 90s everyone was talking about the importance of rotation, but that seems to have just been a swim trend that died off.

  13. SprintDude9000 says:

    >Another common theory for why we rotate our bodies in freestyle and backstroke is so we can reach out further on each stroke. While that may be true at the finish of a race (particularly freestyle), I don’t believe the extension of the arms on the recovery of a rotating swimmer is any further than on a non-rotating swimmer.

    Surely rotating allows you to pull deeper (mid-stroke) and therefor increase torque?

    • Body rotation does tend to facilitate a deeper pull, which does create more propulsive force and torque at the shoulder. Unfortunately, that is not a good thing. Because the deeper pull also creates so much more frontal drag force, a less powerful high elbow pull results in a faster body speed. Using a lot of body rotation with the high elbow pull is tricky, requiring a lot of shoulder extension to do correctly, particularly at the initiation of the pull. The high elbow pulling motion is neither intuitive nor obvious to swimmers. I call the deep pull the ‘power trap’.

  14. coachkopie says:

    Some thoughts:

    * We swim these strokes side to side but we do not get to or ever swim on our side. the actual rotation is modest although it is helpful and vital.

    * The top side arm recovers in a curvalinear fashion and acts as a throw weight

    * The bottom side hip rotates longtitudinally enough to “get out of the way” of the recovering arm to allow for a quick, rhythmic exit coupled with a quick, rhtyhmic entry of the forward entering that drives INTO the water.

    Power and sustainable stroke rate come from rhythm and flow. Have a safe day.

  15. Barb Samuel says:

    Thank You for this fantastic article that confirms for me the efforts I have been making to improve and develop my rotation. I am saving this, to watch the accompanying videos and look forward to much improvement in my movement and speed through the water.

  16. sprintdude9000 says:

    “The mechanical reason is that by counter-rotating our bodies during the underwater pull we can create a significant force to pull against. In other words, we are no longer pulling against just water molecules that are relatively motionless. We now have the water, plus whatever force we can generate with the counter-rotation of our body. The amount of that force that we get to pull against is related to our mass (weight) and to the angular velocity of our body’s rotation (how fast we rotate).”

    I don’t understand what this means, can someone please explain?

    • Sven says:

      I’ll give you my interpretation, but I can’t promise it’s 100% right. Hell, I could be totally wrong.

      Basically, as your left arm is pulling back and your left shoulder is digging down and back, your right arm is swinging up and your right shoulder is coming up and forward. That opposition gives the right side of your body some forward momentum, taking some of the weight of your body off of the water held by your left arm. If all of your weight is being applied only to the water, your hand will slip back through the water more instead of anchoring and pushing the body forward from that anchor. By giving the body more forward momentum at the same time as it applies force backward, we get more out of that pull since the hand will catch and anchor better.

      Also, think about the third law. If we have good opposition, timing, and connection between the shoulders then the upward and forward motion of the right arm, while not inherently propulsive, would add force to the backward motion of the left arm (equal in magnitude, opposite in direction).

      I would say that timing is the key to effectively using rotation. While some coaches tend to take a more-is-better approach to rotation, we see much flatter strokes in the elites. With younger, less skilled swimmers, increasing rotation would make sense. Increase the duration/magnitude of rotation and the timing becomes easier to manage. As timing improves, decrease rotation to increase turnover and power, until you have backstrokers rotating just 30 degrees as we see now. They rotate just enough to benefit them, and then go back for another stroke.

      Sorry for the reply, I hope I didn’t go too far beyond the scope of your question.

      • SprintDude9000 says:

        Hi Sven – I understand what you are saying but don’t think it’s what Gary Sr. is talking about. Thanks anyway though!

        It’s the following two sentances in particular that are causing me confusion:

        “we are no longer pulling against just water molecules that are relatively motionless. We now have the water plus whatever force we can generate with the counter-rotation of our body.”

        • Barb Samuel says:

          What I got from it is that we will be in a body position to create momentum by the use of how the water will flow, and body position. Like an aerodynamically designed car uses air flow to improve performance and speed.

    • Nate says:

      I’m a physics teacher and swim coach and this is my best interpretation so far:
      Where Hall is most expressive about what he is talking about and at the same time most enigmatic is the sentence: “The amount of that FORCE THAT WE GET TO PULL AGAINST is related to our mass (weight) and to the angular velocity of our body’s rotation (how fast we rotate).” This suggests that he is talking about our body’s rotational momentum, which comes from those two factors. The only way I can figure that rotational momentum and the force of the hand pulling through the water can interact is through the torque done by the pull which actually lifts the upper body up out of the water (if you don’t believe me, try laying on your side in bed and doing a freestyle pull). The result of the interaction between the torque and your rotational momentum is that the body fish tails a little toward the pulling arm, an effect we coaches see all the time in our younger swimmers with weak cores. So, if Coach Hall is saying what I think he is saying it is that when swimmers develop the core strength to resist that fish tail effect, the force that would have pushed their hips to the side can instead somehow be harnessed in moving forward. How? I’m still very unsure and too tired to tackle that question tonight.

Leave a Reply

Name will be published. Email address will not. By commenting you agree to our Terms of Use & Privacy Policy.