Applying High Speed Motion Analysis and Video Enhancements to the Individual Swimmer by Dr. Jan Prins (2011)


Published


Introduction: I have the pleasure to introduce to you Dr. Jan Prins. He is a very accomplished coach; he got out of coaching for awhile; very accomplished researcher and educator in the sport. So Jan I’m very excited about this. Thank you for being here.

Dr. Prins: Thank you Steve. Thank you very much. I also want to thank John and the board for the invitation. It is a real pleasure coming back. Last time I was here it was 80-something and I was talking about lactate. Then I started an aqua-therapy clinic after I quit coaching and then came back 7 or 8 years ago. As this is coming up, I should tell you what you are going to see took about 5 years of setting up because high-speed cameras, up until about 3-4 years ago, were about $30,000 a pop. And they were not made to be housed in the water. So that took care of that. The other thing is there are all sorts of little angles we had to get. We had a team of about 6 different organizations helping us to do everything; the housings, the lenses, and helping us bolt all the stuff together. So as you look at this, we can get this up, we have things that you will look at in a half hour that took us 5 years to set up.

I’m nothing if not delighted to be here. If we can get started, what I did, I did not realize that John and Bob had also scheduled me for 4:00. I’m going to do a combined, a little bit of a combined as Steve said, now, and then continue at 4:00. There will be a few repeat slides and then I’ll include some of the things I left off. That’s the plan. And since, let’s see here…
Alright, so, we are going to try something else here. We’re all holding our breath here. It has to be on the hard drive because it is just too heavy. It’s plugged in. The display is what we need to show, right?

Ok, so we’re back in business here. Let’s go ahead and get that up. I want the lights down because I want to show you a lot of pictures and video clips. It would be washed out. It will be a lot easier to see here.

I’m going to, first of all, I had grand plans to have you read this quote right here before I started. But I put it up there because I think what really makes us work and gets us excited is no one is afraid to come up with outlandish ideas. I’m a champion at that. We need to keep throwing ideas out. Every year people keep coming up with ideas that are absolutely wonderful. I am going to tackle a few of them. Let me show you what I am going to do right now. And since we started a little late we might not be able to…

Here is what I want to cover right now. If we run out of time here, I will continue at 4:00. But I want to talk about how we do this and then I want to talk about the middle bullet which talks about torque, anchoring, and interference drag. And those are kind of fun things to talk about.

And then video enhancements is a word we came up with and I’ll show you what I do to be able to actually put these trails and segments on active live video. So here is the 4pm presentation. I’m going to get a little on my soap box and talk about body roll and the role of the scapula, because I think that is worth talking about.

Alright, the first couple of slides are going to give you a little intro on what we do. As you know, biomechanics is a fairly new topic. Came around about 20 years ago. I have been teaching biomechanics or kinesiology for about 35 years. And we taught kinesiology until about 10 years ago and then it became biomechanics and I’ll explain why as we go along. But, uh, there is a difference.

A lot of us are getting a little bit “taken” by some of the camera manufacturers. They are advertising cameras that say 60 frames a second. Now FPS, they don’t say frames per second. What they are really talking about is fields because one video frame is 2 fields. So what they have done to charge $500 more is to make the shutter go and close a little faster. So you are actually seeing the same video frames which is actually 30 frames per second. When you take a video, you take at 30 frames a second. When you want to buy something that is really high-speed, you have to talk about frame rate. That’s what you pay big bucks for. Not this shutter-speed business. So if you spend $1500, you’re going to get 30frames a second and maybe split it up. I don’t want to get too technical for you. But I don’t want people to think they are getting high-speed. So high-speed as I said requires cameras that have high frame rates.

We shoot at 100 frames per second. Any more than 100 frames per second is extremely slow. There are some times that we might need to go a little bit higher, but 100 frames per second, you will see what that looks like.

I thought it would be fun for the first video clip for you to see what 100 frames per second looks like. So, I’m going to play this, and you will see. I’m going to scrub it as the swimmer comes along, so you don’t have to wait forever. Let me scrub this a little bit, but you will see what 100 frames per second looks like. It’s very clear because with normal video you can see at the end it gets a little blurry, but at 100 frames per second, it stays very clear so we can proceed with our analysis. And I’ll talk about all those lights and all that stuff in a couple of minutes, but you can see. That is what 100 frames per second looks like folks.

In our lab, this is what we do. We do all the filming and then we go in and use all the software. The software is also not very friendly to the pocket book. The software costs $16,000. And it took me 16,000 hours to learn how to do it. Because the learning curve was brutal. But now that we got it down, you will see. You should be excited to see what we have here.

Here are the views, and these are very familiar. Incidently, I want to start this by telling you, I don’t think I’m going to tell you anything new. This is stuff you already know. What I would like to do is give you a few things that will makes things a little more clear. Maybe use a little bit of biomechanics so you are a little more effective in your explanations. But here is the front view, and you can see, we have cameras above and below. And this is what it looks like from underneath. The above water camera synchronized was really a waste. And I say that now, I might change my mind later, but when you film above water and you are trying to get the synchronized underwater, guess what, you’re off sync because the stroke in the water and the stroke in the air are off. And so you don’t get exactly what you are looking for. So I dumped the above water and put two of the four cameras underwater.

This is our latest Rube Goldberg. Actually we needed this because all the cameras we used before were anchored to the side and we had the swimmers swimming towards us; which you see here. But what we want to look at, is how swimmers push off the wall. And so we have to have something in the deep. And so as you can see, this is all custom made. So now we’ll get the swimmer pushing off. We’ll get the swimmer’s lateral view so we can look at all the hip velocities and stuff which I will talk about a little bit later. We needed to get this so we could get the push offs which is very exciting.

Those little change on the sides are guide wires. For those of you who are sailors and the like, we need to stabilize the whole mounting because it is seven feet high. So we have these guide wires that hold the camera down and hold its shape. It’s amazing how little swimming and waves hitting the camera can cause shimmy. And we had to go back into the lab and do a little bit more. Then of course, from the side. This is the view from the side, and you can see that we have multiple side views, because we need to be able to get the hip velocities as you go along with just one stroke.

Two weeks ago we took delivery of this. This is our latest toy. Actually it is the fourth camera that we are going to be shooting up from the bottom of the pool. And now we’ll have one camera head on, two from the side, and one shooting up from underneath. I will show you what those video clips look like. But, uh, everything there you can see. It took us a whole year just to get this organized.

In biomechanics, the camera does not budge and that is because of the calibration. The software has to interpret real units to pixels and if the camera moves, that cannot happen. So we do not pull or push. Once the camera is set and I want to make that very clear. I’m going to show you that we need the stability.

The mountings are bolted to the pool deck. This is one of our teams. We had to get these guys to come and actually run mounting, bolts, and anchors along the pool deck to hold the cameras. And here is a picture of what that bolting looks like. So the cameras are put in a held firmly to the side and we cannot move it. Once we are done with the filming, of course, we go into the lab and use the software.
Now, you may be interested and you maybe already know this but land based stuff uses different systems. Nikon, who also markets the software that we use, has this system where they use infrared light that are fired up from the ring that’s around the lens that you see and bounces back from those illuminated dots and then right back into the lens. That’s how they do it on land.

As you can tell in the water, there is no way you can play around with light going back and forth. The signal is going to go all over the place. So we had to try to come up with a different way to do this. But I thought you would like this before I talk about the water. If you think biomechanics hasn’t proceeded. It has gone to the horses. And I wanted to say donkeys, but my wife said they aren’t donkeys , so don’t speak and act like one.

So in the water, we had to come up with a way to simulate those really brightly illuminated lights. So I had to get together with another person and design these LEDs. He said these LEDs were really going to give us the bang for our buck. So we now have a custom designed battery pack. With these LEDs. And we tape it and the word has gone out with the USA swimming team that if all costs are being recruited. They are all my guinea pigs anyway. We put duct tape to them and when they get out of the water, I walk away because I don’t want to hear it. I say, “You are getting a free waxing!”

So here’s what we do, and then, we of course get in there and then I will do a quick – Contrary of what we do here, and I will scrub this because the digitizing is really critical. When we digitize, we hope that when we use digitizing. It will be automatic for the most cases. Can you see when she presses the button, it advances quite a bit. Now it has to catch again so you will see her pulling through and then all of a sudden the whole thing advances through to the whip. See that? Now, what that is really doing is making life very easy for us, because one of those passes is 800 frames. And we have five data points times 800. That’s 4000 and we have 12 runs for each subject. We are talking about 45,000 data points. We would be there all year if we had to go frame by frame. So the automatic digitizing feature is absolutely critical.

What we are doing here is looking at these. This is what we are interested in; displacements, joint angles, velocities, accelerations. And then, the real power of all these things – we jump through these hoops so we have a way to generate a report.

Now I’m going to show you a still picture of this report just so I can tell you what is going on and then I’m going to show you some moving stuff. But the software is very, very good. What it does is it allows us to combine a video image or a number of video images that you see with a graph or number of graphs. We can graph what we are looking for and the software is going to match it. So what I’m going to do is show you now some video clips of the reports.

But before I do that, I want to tell you something that we all know. This all revolves around one thing: how to increase hip velocity. That’s it! Everything we do boils down to one thing. You have to get the hip velocity higher if you want to be swimming faster. So, all this mumbo-jumbo in the second bullet; all this scientific translation, all that mumbo-jumbo just means you have to use your arms and legs in a cyclic way to get those hips moving.

So, here is what we are focusing on right now. We started with the freestyle. We have probably been collecting data now for about a year. And this is the first study we did. I tried to keep it as simple as possible. We looked at the bent vs. straight arm, dropped elbow, and the “you know what” S-pull. So, I am going to show you the results of that.

I presented this preliminary stuff in Norway last year at the Biomechanics Conference. So let’s look first at bent vs. straight arm. Here’s the first finding we had. And again, I told you, I’m not telling you anything that you don’t already know. I have to tell you, when I saw this and I was talking to Dick Hannual about 6 months ago, I said, “Dick, guess what? Most of these swimmers are about 110-130!” and he said, “I knew that all along.”

So, I started to realize, and I am going to make a case for this, and we see this, and the day before yesterday just before I left, one of my grad students was going through a bunch of these subjects. We have 24 subjects. He said, “I didn’t see any elbow bends any less than 110 degrees.” And so, in spite of people being told to bend at 90 degrees, there is something intuitive with good swimmers that they are not going to do that. And I am going to tell you why. Because I think it is very important that we understand why.

And I don’t want to belabor this by showing you a bunch of pictures, but this is an obtuse angle. The corresponding result we got is you can see that the hip velocity that occurred in the middle of the stroke. Now, if you had asked me up until last year where the fastest part of the hip is moving, what part of the stroke is fastest? I would have told you at the end of the stroke. I would have thought that the last little bit caused the surge. Well, I’m going to show you a video clip and we’ll see what you think.

Ok, here’s the video clip. I’ll play it first and then I’m going to go back and I’m going to do it again. So here is the clip of the swimmer. You can see the water moving. My wife told me that the people are going to fall asleep if I do not hand scrub. So let me go forward a little bit and then I’m going to stop it, and tell you what we are looking at.

The top is hip velocity. Like I told you, that is the bottom line. We are plotting hip velocity here folks. And this is hand velocity that we just plotted the speed of the hand. And there is a vertical bar and this s going to appear. This is real power, this is why we pay $16,000. That’s going to coincide precisely with the position of the video. So let’s play this and I think you are going to see something very interesting.
Here it goes, again we are videoing at a very high speed and here is that vertical bar. Now, this is the peak. If you see what I see, it is the middle third of the stroke that generates the highest hip velocity. Now why? Well I stayed up and talked to a lot of people. But that is where the highest speed of the body is. And I will tell you why. It was really fun for me to prepare this lecture because I’ll tell you why. The other things also, and let me preface this, the reason you just see one curve is because the calibration is only based on what we see on the swimmer at that time. You don’t see swimmers starting at zero speed, but the software interprets where the calibration is. So, don’t worry about that.

Also, notice down here that the hand velocity and then Bob and I have a little bit… I agree with Bob, this is not something that we can explain that easily, even though we would like to. But I told Bob, the hand velocity preceded the hip velocity. I’ll go back. Can you see how the hand velocity came a little bit before? So I got all excited to go tell Bob – that may or may not be – which I agree. I think you have to move your hand to generate the movement before your body moves over. Now we will see with swimmers if that is more and more happening, but for this time, it looks like that is what’s happening. And I am open to any and all suggestions.

But let me make a case. Now that I have shown this and we can play it right here, we’ll talk about why. And to talk about why let’s take a little bit of a detour and talk about the 90 degree elbow pull. I think we have been living with the 90 degrees for the past forty years. So it is worth talking about.

Remember, when we talk about 90 degrees, kinesthetically, neuro-muscularly, the brain interprets the easiest way to move. When you are working with a fixed resistance, it’s close to about 90 degrees. And that is to do with the later talk which I will talk about. That is because this is a fixed resistance. Now, why is that? Why does the brain interpret that? Because, we are dealing with an external torque. Alright, again, I don’t want to put you to sleep. But that is because we need to decrease the external torque.

So, why wouldn’t we pull with a straighter arm then? Why do we need to pull more with a straighter arm then? This is the short answer. Because the water is not a fixed resistance, folks. I don’t know about you, but it takes a long time for things to sink into me. But I, all of a sudden, it struck me. And I have a friend, a colleague, who is an engineer, and we were chatting away and all of a sudden we realized, water is not a fixed resistance! So, let’s make a case for this here.

This is the more detailed explanation, so bear with me please again. We use propulsive drag forces to swim through the water. That is the majority of the forces. I think there is enough literature out there that has banged that into us enough. Lift forces are clearly secondary. Drag forces, under specific conditions, are, in this case, used for propulsion. So, we have to go back to a formula.

So, hang with me. This is the formula that we use for drag forces. And the one I highlighted and made bigger in red is really what we are focusing on. By moving arms we are directly concerned with the velocity of the hand. So, let’s read this together: for a body segment moving around on an axis of rotation like in the shoulder. As the hand is rotated in a path that is further and further away from the axis, the linear velocity is increased. So, as I’m pulling, the middle third of the stroke when my hand is pulling away from the axis of rotation, it is traveling at a higher velocity, so voila! That’s because water is not a fixed resistance.

If you look at above water examples of this, these are two very good examples of why we increase the radius of rotation when we want to increase the maximum velocity. You can think of anything. This is just two examples. Hitting a golf ball, serving in tennis; whatever it is, if you want to increase the velocity, you increase the radius. Further advantage of pulling with a straight arm – and that is straightER arm, not straight arm – I wanted to make that clear. Straighter arm, the greater the distance traveled in the trajectory, the greater the distance per stroke.

Now, there are advantages of a bent arm, of course. I’ll be talking more about this 90 degree angle or acute. Hands are going to travel in a smaller trajectory; a shorter angular distance. But, with a more linear trajectory, once the water is set in motion, it will offer less resistance. So I thought I would be a little creative and find the most outlandish looking paddle-wheel picture. But that is the example that we use to show a successful engagement of the water in short increments – small increments. Once that plane of the paddle grabs the water, it gets the heck out of the way and makes room for the next plane.
And that is in contrast to something like this which is successful on land, but disastrous in water. Doc, I remember his talking to me about this guy that got a bunch of investors to build this paddle-steamer at the turn of the century. It had the continuous track. And everyone went down to the grand opening and the darn thing didn’t move. And we all know why. Once it engages the water, it kept pushing the same water. But this is not the formula.

So, how about swimming with a fully extended elbow? And this is where we have to take a little bit of a look at what torque is all about. And if you know, again, this is something you all know, but torque is force times force arm.

More importantly is the trade-off. And I said, we instinctively bend our arms when we are moving a fixed resistance to about 90 degrees because we want to reduce the external torque because it has to be matched by the internal torque. Now, I thought it might be fun for me to show two examples before we get to the shoulder before we get to what all this torque business is about. In my very beginning biomechanics class, I got this picture. It is a very old picture. But it very much illustrates the business of trading off external and internal torque. Can you see all the external torque on the one side? The person lifting? You multiple force times force arm, you get and additive effect over here. And guess what? It has to be neutralized over on this side. We have a very small force arm and if it has to take care of all these torques to get a huge amount of force that is necessary on our lower back muscles. It is a very easy way to understand torque.

The other one I also thought would be fun to talk about is the way the head works – and this is a fairly new textbook. When we have our head in a neutral position, we only feel about 25 newtons. Which is about 8 pounds of force. But you start tilting you chin forward, you stare at a computer that is not properly placed, we put force on our necks which goes up to 100 newtons. Which is about 25 pounds and that is quite a bit of weight.

So again, we are talking about how external torque, the weight of our head – which is about 10 to 12 pounds can makes us work awfully hard. So, here we go to the shoulder, which is really what we are interested in. And you can see how the external torque has to be matched by the internal torque. This is why we bend our elbows to 90 degrees when we are dealing with a fixed resistance.

So, I hope, I know this is as clear as mud, but I hope I made some illusion to what we are looking at. So, I think as a summary of this torque business, long workouts performed with fully extended arms impose repetitive internal loads on the shoulders.

There’s another problem with this also. Not a problem, but there is another factor here. It’s called a moment of inertia, folks. So, there is a little more to this than meets the eye. The way our masses are distributed is very important and that is called the moment of inertia. And, again, it is a fancy word, but the concept is pretty neat. And this is a great picture. It tells us how our design took care on inertia far before we realized it.

What this shows is why we are designed in a fashion where our larger masses are closer to the middle of our body and we taper off because of moment of inertia. If the masses are reversed, like the right-hand picture, we would have to work a heck of a lot harder to move our external extremities. So, moment of inertia is a very important concept; especially when you are telling kids to straighten their arms, lift their arms up, and recover with straight arms, etc.

Bob and I were talking about this, and he thought this was fun, and I agree. This is a reverse application of moment of inertia. And if you’re wondering why the heck we are looking at this here, let me explain. Tight-rope walkers use these bars and they even have people hanging on it and riding on bikes and doing all this stuff. And people are going, “oh man, this guy has to balance himself holding this big long heavy thing, isn’t that great?” Well, what is happening is, that bar, because of the moment of inertia being extended, is making him more stable. Making his center more rigid.

So, you can reverse this argument. If you have something that is extending far away from your axis of rotation, you’re working much harder at the other end. That is the point I want to make. This is a fun example of the reverse. Therefore, to move a mass of the arm that is distributed further from the shoulder places more demand on the muscles responsible for the movement.

I will leave it at that, and I would be happy to talk to you at any time about moment of inertia.

I told you the other things we worked on were the dropped elbow and the s-pull. And I am going to show you a little bit of the reports we generated when we had the high speed from here. This is the classic. I won’t show you this, because I don’t want you to lose any sleep or throw up, but we asked the subjects to purposely drop the elbow. So, I’m going to show you, and you can see what is coming. I mean, there is not a person in here that doesn’t know what is going to happen. I’m going to play this and watch this. I’m going to play it in its entirety and not slow it down.

And look at this right here. This is hip velocity, folks. Right here. You can tell what is going to happen. When he drops his elbow, guess what happens to the hip velocity? It plummets. And so, something we always knew. I will show you a still picture so we can talk about it. When you drop your elbow, you’re going to go slower. But what we also found out is how much different you hand speed is. Look at the speeds between the hand, when the guy was dropping his elbow, which is about almost one meter per second faster. So, we all know this. You drop your elbow and your hand moves very fast. And we can talk about relative hand speeds, but you can see the difference from the numbers that we got. It is pretty frightening, but you can see how much of a fade-off there is with the dropped elbow with the hip velocity.

In interest of time, let’s go on to the infamous s-pull. Now, I wrote about this because Dick and Nort were finishing up with the new version of The Coach’s Bible and they very kindly asked me to write the chapter on the science. And I put this in there and I want to repeat what I said here. The problem has always been misinterpretation. Because when you look at something on a flat piece of paper in two dimensions, that is very different than what is actually going on in three dimensions. Here is a clip that I got from the Beijing footage of Park from underneath. And you have all seen this. And this is him in the 400 finals. And what we did was use video enhancements. That was the path of his hand.

I’ll play it one more time, and you tell me if he is actually making an s-pull or whether this is what we are talking about in difference in interpretation. You see that? Let me show you a still picture, so we can talk about it. That is not what he is doing! I hope you agree. That is what it looks like in two dimensions! This actually takes place in three dimensions. And that is where the mistake has always been. And so, no more s-pulls. We know it doesn’t work. I’m going to show you a report here from the high speed study and this will really be enlightening I think.

Watch this girl. She’s going to swim towards us and I will set you up. She is going to come and start. She’s going to cross over a little bit and then she is going to pull out. Speeds are going to drop and she’s going to come to the middle. Speed is going to pick back up and then it is going to drop again.

Let me show you what we’re doing here. And again, the beginning and end, we’re going to be looking at something here. Here she comes and watch her hand sculling out and purposely doing this s-pull. Here she is, let me go back- She’s crossing over a little in front, we won’t hold that against her, and as she starts to go out wide, watch her hips drop. You see that? Her hip velocity has already been compromised.

Then, it picks back up because as we expected she is doing something differently here. And so you can see how her hip velocity has come back up. And then, she has to recover from that, so she has- We’ll go back. So, right about here, she’s coming underneath and so her hip velocity is going to come back up. And then look what happens when she tries to go back out and get her hand out of the water. See how her hip velocity slows down again because her hand is sweeping over from underneath her belly button and trying to come up.

We’ll talk a little bit about interference drag. You see, she starts here, starts to go out wide, her hips drop and she comes in underneath and her hips come up again in velocity and then drops back down. So this I think, you can see, you can appreciate being able to look at this in high-speed can really make a difference.

So here is a summary of the points. More of an obtuse angle which we are now really realizing. And then the middle third of the stroke is where we have the highest velocity. And then I said the s-pull is passé.

Let’s go ahead and talk about anchoring. This is a good thing for us to chat about. Ideally, we want the hand to move minimally. This is an old picture that I found; which is a nice picture. It is utterly idealistic. You have the hand holding. If it is holding the lane line, I can buy it. Right, because the hand is coming out exactly where it entered. So, we all know that is absolutely impossible. Because, the reality is when you start pushing the water, it is going to move. The water is going to move whether you like it or not. You’re not doing a pull up on a pull up bar. The only reason your hand will come out at the same place or maybe a little further is if you are kicking or doing something else. Once you pull the water, the water is going to get out of the way. And so anchoring is a wonderful thing to teach the kids, but it is not what really happens.

So here we are, I’ll show you, this is what we are doing. This is part of the extended part. Once we are done with the s-pull and all that stuff, we are going to look at anchoring. And we have a way with the software to track where the hand goes in, where the hand comes out, and look at the difference on what happened. And over here, before I play the video, I will show you, we can put the numbers in and see where the pull began which is somewhere around .6 meters and came out at .3 meters. So it moved back. We asked her to do an s-pull which is worse. You really can’t get a lot out of that. So you have a problem with anchoring because there is less anchoring with an s-pull.

Here she comes right here. See how the hand is going to drop and she’ll go up. And then her speed is going to drop back down right there. So we’ll interpret this, but let’s not forget here that you have to combine anchoring with sufficient hand velocity if you want to get enough displacement. So, here’s a video clip. We have 2 video clips; one with fairly good anchoring and one with terrible anchoring. Watch, this is kind of fun to see; more visual.

So, he’ll pull and there’s his hip moving and then as he goes back, you can see what happened. His hand moved and went in, he went back a little bit, but he was able to pull his hip quite a bit. In contrast, I asked him to slip; just to grab and go for it. This is what it looks like and you can see the difference his hand went in and went out and you can see how much his hip actually moved back. Play that again. There we go. You see the difference of where his hand went in and came out and how far his hips actually traveled back. You see that? There was barely any displacement of the hips even though the hand traveled a huge amount of distance.

So, optimal propulsion: we want the hand’s velocity relative to the water to be fairly low. And you want to hold the water. And the velocity of the body relative to the water or side of the pool can be thought of as high, but we want it to be low in relation to the body.

Now, let me talk about this. Interference drag is one of the things that is going to be really topical. Thanks to Dave Salo and Rebecca Soni, I think everyone understands there is something going on with the way the hands do not need to come all the way in. And so, by definition, interference drag is the drag that is created when body parts move close to each other. There’s a whole bunch of examples and we can go on and on. Here are the typical examples that we are looking at; Freestyle coming at the end, backstroke finish, even entering with the hand going right by the head which is more subtle, but who knows. One we are really focused on right now is the breaststroke recovery. So it is not just the speed at which you can make the transition and go from in-sweep and push your hands up front but there is a definite change in the drag forces. That is called interference drag. So, I think, that is really exciting to see what happens. There are many examples.

We’re going to use this camera. This is one of the reasons I got this camera. And I’m going to show you a video clip which is kind of fun to see, but we are going to look at interference drag. Because now we can shoot straight up. So here, is a picture of a guy taking a butterfly stroke from the bottom and you will see, he is doing the old keyhole-pull. But that is what it is going to look like from the top.

And then we got to the next picture and I will show you breaststroke. And I’ll tell you what we plan on doing to look at this with the high-speed stuff. He’s bringing his elbows a little closer. The interference drag we are going to measure is again going to look at hip velocity and wingspan. We’re going to see just how far and how the changes in the hips are as they come closer and closer in. What I expect to see – and we are going to have him put a pull buoy on first – is that the closer they come the more abrupt change there will be. That is what I predict. Now I could be way off. And the less they come in, the less fall-off there will be of hip velocity.

So if we film at high-speed and we look at the amount – the transition of the hands when they come in closer and closer, we might see a change in hip velocity. Which would tell us what is going on. So we are going to do that with fly – we’re going to do that with all the strokes. But since we just took, uh, delivery of this underwater camera just now, this is something down the road. But it is definitely going to be fun to see.

So how does this deal with the statistics? I think for one thing, since I am supposed to publish all this stuff, I told people, “Do you know if it met statistics?” If it doesn’t meet statistical marginal error and significance and all that stuff, it doesn’t mean beans for us here. Because 1/100 of a second may not be significant on paper, but it sure is significant for us. And so I am very clear on this. If it isn’t, then I publish and run the statistics and it shows that there is no real significant difference (if it is 1/100 of a second), it is significant as far as we are concerned.

This is what we call video enhancements. About two years ago I started playing with the software. And you see the effect here. We call them enhancements. We can put, what we call, trails and segments on video. So, I’m going to show you examples for each stroke of these video enhancements.

First I’m going to show you freestyle. We’re going to look at the EVF. We’re going to go. The forearm is nice to see, body alignment, elbow position, and symmetry. And here’s the first one. Now, last year on the way to the Pan Pacs, Rohan Taylor and a couple of the Australian coaches hung out at our pool and trained so that we got a chance to film from really good Australian swimmers. And you see, this is the first person. Very good freestyler. Let’s take Kelly Stubbins here and see what these enhancements look like. So, this is a trail. We call these trails. And as you see, we have color-coded the left and right hands. And You can really see a nice vertical forearm to start.

Next example, I’ll show you. And this is going to be a really good teaching tool for one of the kids in beginner swimming class; very easy way to tell them what’s going on.

Next one I’m going to show you is Kelly from the side with the trails. Remember, these are just trails. So, you will see, we coded the elbow and the hand. And you can see the trajectories. And I will talk a little more about high elbows and stuff in a second. So, that is the trails from the side in freestyle. We also, as I said, can do segments. And segments look like this. You identify the joint segments and connect the dots so we have this longitude and latitude axis between the joint segments. And you’ll see what I mean. See that? And this is all moving video. So you can see how they interact as they go along.

Next one will be Kelly here with the lateral segments. And we went one step further. I think you’ll be curious to see what we did here. We actually super-imposed the grid. So you can see, we can get a little bit more picky about what we are looking for; putting that grid on. I’m fortunate to surround myself with people who are better than me. But you can see a lot more with a grid.
Here is what I did to show we can use the trails to look at elbow position. So I have three examples. This is the first one. And you can see what the high elbow looks like when it’s coded for the elbow and the hand. And I did a still picture here just so we could make a point. And that is – and this is maybe a nice way to talk about high elbow with the kids – you say the elbow stays relatively stationary while the hand does something at the beginning of the stroke. And you can show them the picture like this and show the elbow hasn’t traveled that much while the hand goes down. The first 3rd is what you see when the elbow is stationary.

Here’s what I call a neutral elbow. Which is the elbow and the hand moving at the same time. So there’s a very paddle-type of style with it. That’s what I would call a neutral elbow; both hand and elbow traveling at the same time. Then the next one is what keeps us awake at night. I tell people, “A dropped elbow is the next thing to drowning.” No, I didn’t say that.

Let’s move on quickly. I have some backstroke examples. This is Sophie Edington, who won the 50 free at Pan Pacs last year. This is what she looks like when she swims toward the camera. You always start with some footage before you put the trails in. As you can see the path of the hands, what happens at the end, and you can actually see a slight difference – or a big difference in her case – of the two hands.

This is Sophie with segments. And you can certainly see that there are different things you can see with each looking at the trails and the segments. Here we super-imposed the grid. And you can tell as you go frame by frame – which I won’t do right now at the expense of time – but you can see the difference of where the hand should be when you pull.

The next picture here is Sophie from the side. And these are lateral segments. And you can tell again the amount of knee bend, the extent or amplitude at which her legs drop. You can tell pretty much how straight she is lying in the water. Right here she has a nice position of the hands. You see how straight she is lying – that’s nice alignment.

One more backstroke. This is one of the swimmers on the UH team. And you can see the depth to which he lets his hands sink at the entry. And again, showing someone something like this is quite powerful. Yes, he is very, very deep. And you can imagine putting the grid on and showing him the finish is almost even deeper than his entry.

Breaststroke. I’m going to show you breaststroke front pull and kick. Body alignment and this is a familiar name. Leisel Jones was there and so I’ll show you a couple of trails and segments with Leisel. And here she comes, we did the trails first. Putting the grid on and you can see how symmetric her arms are and pull is. Look at that. This is Leisel from the side on the segments. And I think you are going to be very, very interested in what you see here. And this is a world class breaststroker and I am going to stop it. Let me scrub this and I’ll show you what is really amazing here with her. You can see how straight she is. That is pretty good alignment. Beautiful.

The next one is her swim teammate which I think you will also be very interested in seeing. Here she comes again and you can see how straight she is. The segments really show a lot. Look at that. That is dead straight. Very nice.
Now, her teammate, Sarah Katsoulis, filmed at the same time. Also, as you know, she is a great breaststroker. We saw something very interesting. After we saw this, we grabbed them and put them right back in the pool. And you will see why. You see Sarah, and again, it’s not so subtle when you do the segments. But it shows alignment. Can you see that? She’s bending her elbows – breaking her elbows. See how her head is down. She is not really as straight as she can be. So, right there, you see the bend in her elbows – she’s not as straight. So he thought that needed immediate attention.

So, here, before I get to fly, I’ll show you this young lady. She is one of my graduate students who turns out to be the North American champion of what we call dynamic apnea. This is a little crazy. They try to swim as far as they can underwater. She’s perfectly neutrally buoyant because she has got this thing around her neck. And you’ll see. This is world class. Watch this. You want to see streamline, because they have to conserve. They are very interested in going far. That’s the bottom line. But watch her, and how streamline she actually is. She’s just going to go and go and go. And look at that. Beautiful streamline. I thought you would get a kick out of watching this. Her record is 114m underwater. I think the record is much farther than that, but this is what she’s working on.

Now here’s Leisel from the back; breaststroke kick. This is a great way to see if the symmetry is there. This is her kick with the trails. Watch now. She is right in front of the camera. Very nice symmetrical kick; world class swimmer.

We’ll also get a chance to look at timing in breaststroke. Here’s Leisel. You can see her heels as well as her hands. You can tell the difference. And really, the rate in which her hands come forward versus the rate her kick goes. And I think as we look at it further and examine it a little bit further, the better breaststrokers, you will see a little less of a lag as the hands are waiting here for the feet to come up. And that might be something that you could be thinking about.

The last couple of examples I want to give you before we hang it up. In butterfly, this is Tao Li, who won in the Asian Games. A good flyer. We filmed her here last year. Here’s she comes. We’ll put a grid on. And you can see again, nice symmetrical pull. And here’s this one which I had to get permission from Rowdy because I had to grab this frame from his video that he made years ago with John Moffet and Pablo Morales and made this very nice video. I’m sure some of you remember this. But I’m throwing this out to you because now we know the diamond pull. And I have to thank Steve. He is the guy that brought it to my attention. But here is Pablo in 1992, filmed beneath the water. You tell me if you see a keyhole pull which we were talking about before.
Here is Pablo. I’m sure he thought he was doing the keyhole pull. To repeat, Doc had a famous saying, “Swimmers swim fast in spite of their coaches.” In 1992 Pablo realized that his hands would do a lot better if he did what he was doing there, not following this classic textbook keyhole pull. So, I think it is food for thought.

And the last slide I’m going to show you is another of fly. And looking at the side with the trails; it’s nice because we can see the hips and the feet. And so you can tell the amplitudes of the feet and how steady the hips are. And here is the other guy, and he is not doing that. You can see a slight difference in what his hips and his feet are doing. So, again, a pretty effective way to teach visually with these trails and segments.

Alright, so. I am done with this portion of it. So, I’m going to have two shameless plugs. And I am cribbing for Michael Medved. He likes to push The Journal of Swimming Research. John asked me to take over as editor two years ago and it has taken a while to get it going. But in about a month you are going to see the first issue. And the first two issues are going to be strictly overviews. This is not active yet. I just wanted to show you what it is going to look like. Ernie is going to be in it. We are going to do part one about muscle. You can see the article, Training for Muscles. A guy named Ross Sanders is going to talk about symmetry. And Ted Becker has written stuff on the shoulder. It’s going to all be reviews for the first two issues. And you can see also, I was insistent that nothing gets published until everyone has a coaches version. So we have a number of people in the audience who have written to be on the coaches review board. We’re going to send it to them, and if it doesn’t pass with the coaches, it will not be in. And so, that is it.

And the second shameless plug here is for the website we’re going to put up. It is called Swimming Biomechanics. And I’m going to do all this video stuff. And in case you have the urge to drop me a note, this is my email address. If you are misguided enough to want to get a hold of me, please do.
And the last slide is a quote. And then, thank you very much! Thanks for coming!

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