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Expand your running knowledge, identify running misconceptions and become a faster, healthier, SMARTER runner. Let Brodie Sharpe become your new running guide as he teaches you powerful injury insights from his many years as a physiotherapist while also interviewing the best running gurus in the world. This is ideal for injured runners & runners looking for injury prevention and elevated performance. So, take full advantage by starting at season 1 where Brodie teaches you THE TOP PRINCIPLES TO OVERCOME ANY RUNNING INJURY and letβs begin your run smarter journey.
On today's episode, Understanding and Enhancing Running Economy with Mark Konick. Welcome to the only podcast delivering and deciphering the latest running research to help you run smarter. My name is Brody. I'm an online physiotherapist treating runners all over the world, but I'm also an advert runner who just like you have been through vicious injury cycles. And when searching for answers, struggled to decipher between common run... myths and real evidence-based guidance. But this podcast is changing that. So join me as a run smarter scholar and raise your running IQ so we can break through the injury cycles and achieve running feats you never thought possible. Welcome back Run Smarter Scholars. We have Mark on the podcast today who has just released a paper titled Individualization of Footwear for Optimizing Running Economy, a Theoretical Framework. We dive into the paper, the reasons behind it and the insights that can help you learn about running economy, learning what it is, how to become more efficient in particular with different footwear and that type of thing. I'm excited to have another researcher on the podcast today. I know you're gonna enjoy it. Let's take it away. Mark, thank you very much for joining me on the podcast. Yeah, thanks Brodie. Thanks for the invitation. It's good to be here. I'd like to learn more about you to start with. So can you start off with like, what is your profession and what led you to writing this paper that we're gonna talk about? Yeah, my background originally was in computer science. That was my first degree and I worked in IT for a few years and then had to change the direction, went back to study and finished up doing a PhD in sports biomechanics. and physiology. And that led me down the path of being a postdoc. So I've been a postdoc and lecturer as well over the last few years, predominantly around the areas of sports performance. So it's really understanding all sorts of factors that underlie human performance. And this has been in elite sport and also recreational sport and in para sport as well. covers across a broad range, but the underlying work is around understanding human performance. Cool. And the paper that we're going to discuss today is Individualization of Footwear for Optimizing Running Economy. So was there any major ideas around how that paper came about, that particular idea? Yeah, I mean, the paper itself has been in development for, I mean, since its origin, since about 2020, 2019, 2020. So originally I contributed to a group that was just created by World Athletics who are governor and administer track and field internationally. And what they wanted to do was at that time when the super shoes were, you know, two or three years they've been around, they were looking to develop some regulations around how they could regulate the shoes in international competition. So this was like, this was the end of 2019 into 2020, just before the COVID pandemic. So at that time there was some scientific evidence around the fact that these new shoes were improving running economy. And the key properties that were there were that, you know, there was lighter mid-soils. sorry, yeah, lighter mass, thicker mid soles. And then there was this carbon fiber plate that had been around for a few years, but was now appearing in all of these high performance shoes. But there wasn't really too much evidence around how these properties come together and how they cause the improvements in running economy. So that's been a sort of a focus for the last few years of a number of different researchers in this area. But at that time, The Tokyo games are still going ahead in 2020. So World Athletics, they had to make a decision. And the decision that they adopted was to regulate the thickness of the midsole. That was the key one at that time. They also limited the carbon fiber plate to a single plate. That was another one of the regulations that they brought in. And this was based on A prevalent idea at the time was that if you limit the thickness of the midsole, then you limit the amount of technology that you can get into the shoe. It was an idea formally put forward by Jeff Burns and Nicholas Tam in a paper. I think it was published in 2020. So that was the path that they took at that time. And, but I left feeling that. that whilst it was the best that could be done at that point, I felt that there was more that could be done. I think there's plenty of opportunity to develop technologies in a way that would overcome those rules essentially in the longterm. So initially it was around developing a model that would estimate the mechanical effect of footwear. And then I had to provide a broader context. for where that model fitted into the whole sort of biomechanical system. So that's essentially what this paper is. It's describing that framework. Looking forward to diving more into that framework as well. But setting a little bit of context for those everyday runners who aren't familiar with what running economy actually is, could you best describe it? Yeah, so running economy is, it's the gold standard measure of oxygen cost or energy cost that a runner uses to move their center of mass at a constant submaximal velocity. Um, so submaximal here, what we mean by submaximal is, um, that the, the runner is, is moving at a speed, which is lower than their, lower than, um, their lactate threshold, if that's a familiar concept to you. To my understanding, it's like, there's a certain intensity where if you switch. just to a higher intensity, then your body starts to accumulate lactic acid more than it can remove and you sort of have this exponential kind of build up in a way of lactic acid, would that be fair to say? Yeah, yeah, that's fair to say. Yes. So if you're, if, if a runner is up, running at an intensity that's under that threshold, um, then we can quite accurately measure the amount of energy that the runner uses and, uh, and so. When a runner runs at a constant. If you imagine just ring at a constant speed on a treadmill, uh, we can then accurately assess how much oxygen and how much energy it takes for a runner to, uh, to run at that, at that speed. Okay. So in terms of running economy, we're, if we're wanting to enhance our running economy, we're looking at either finding a way to utilize more oxygen or like. You can, you can run faster while using the same amount of oxygen. Is that right? Yeah, that's one way of looking at looking at it. So a higher speed for the same amount of oxygen or for a given speed using less oxygen, gotcha. Yeah. And of course, if, if a runner's using less oxygen to run at a given speed, um, then they have more energy effectively to, to be able to main that speed for a longer period of time. Yeah. That also makes sense. We could also like, yeah, applying this to say a marathon, if you have your marathon pace and. You think you can hold this pace at for the duration of the race. If you have an improved running economy, you could probably last that. At that speed for longer within the race, or you could essentially run have a slightly faster race pace and still accumulate that same amount of effort or utilizing that same amount of oxygen or essentially approving upon that time. Yeah. Yeah, exactly. Obviously that'd pick up a lot of runners ears if we're talking about improving marathon times and those sorts of things. Um, your paper mentioned something about the direct effects and the mediated effects of running economy. Can you talk what, uh, divide the two and, um, describe what those are? Yeah. So it will help if, if the diagram is in front of people, uh, as I'm, uh, this describing it, but, um, what we're dealing with here is I suppose that. It's an attempt at getting at a causal model of running economy. So it's understanding the main variables in terms of footwear, at least, the factors that are influencing running economy. So, um, the, the first, the first thing that happens is that the runner has to have some sort of intention, as opposed to, to want to change or improve their running economy, uh, they can do that through various means, one of them's through training, um, but another one is through as we've come to find out through changes in footwear. So the primary cause, I guess, in this respect is that there's a change in footwear. And that's placed in the diagram at the bottom left, if anybody's got it in front of them. And then from that change in footwear, you've essentially got two causal pathways. One is a direct mechanical effect of the footwear on the spring mass characteristics of the whole system of the leg, of the body leg and shoe system. So the spring mass system is probably worth just elaborating on a little bit. It's one of the most, I guess, important concepts in running in the sense that the human body running can be modeled as if it were a... The leg was a spring and the body was a mass on top of that spring. And when the foot lands on the ground, the body causes the compression of the spring, which stores energy in the leg, in the leg spring. And then through the second half of the stance phase, that spring recoils and releases that energy back to the system again. So you can model this spring mass system quite accurately. And the force time curve. force on the ground that you see across the stance phase. The curve is as if it was behaving, the body and leg was behaving like a spring. So the idea being that if you can improve the efficiency or the economy of that spring, you can reduce the energy that you're having to generate in the muscle. So there's two effects on this spring mass system. One is the mechanical effect of the footwear. So it's a sort of a direct, we're calling it a direct mechanical effect on the spring mass characteristics. And then the other one is the mediated effect, which is how does the footwear affect ankle and foot biomechanics, which in turn then affects the spring mass characteristics as well. Gotcha. So the ankle and the foot might be moving differently if you are having different footwear. And for those who don't have the diagram in front of them, if you can imagine like a triangle shape where you've got like a characteristic to each corner assigned to each corner, and like you say, the bottom left says changes in footwear properties. And then you've got two different directions of the triangle that can move in, you can move up to the top corner of the triangle that says ankle and foot biomechanics. So the shoe itself or the changes in the footwear itself can change what the ankle does and what the foot does. And then if we look to the bottom right corner of the triangle, we're looking at spring mass, spring mass characteristics. And so the footwear itself, when we change the footwear, it can directly change that spring mass characteristics by making you a more efficient spring directly, or it could indirectly change it by you. Moving your foot and ankle differently, which then correlates moving down the, um, the slope of the triangle, moving back into spring mass and having an altered running economy that way. Fair to say. Yep. Couldn't put it better myself. The other thing is then that there's a line that joined that goes from the spring mass characteristics to running economy. And the idea is there is that if you, I run a, if you can reduce the amount of energy, um, used by this, the spring mass system, then those energy savings are proportional to changes in running economy itself. Yep. Okay. Um, how is this footwear, if we're looking at the direct effects, like directly making you, uh, turning you into a more efficient spring where we are absorbing and recoiling this energy that we're providing when we hit the ground. If we want to become more efficient than that, how is the footwear doing that directly? Yeah. So in the paper, we define a given more technical definition of what a direct effect is. To try and sort of break it down, it's the effect that a change in the mechanical properties of the footwear, what effect that has on the spring mass characteristics of the system in absence of any changes in the ankle and the foot by mechanics. So if you could somehow hold, you've got one footwork, you're wearing one pair of shoes and you have a certain response in your ankle and foot, if you change the footwear and you could hold the ankle and foot mechanics the same, then the system would be forced to adapt in a different way. And that would be technically what the direct effect is. So... If the properties of a new midsole are different to the previous pair, for example, the midsole will inherently behave differently compared to that previous footwear under the same loading conditions. So for example, it may be associated with more energy stored in the midsole, more energy released from the midsole. And what this does is it contributes to this is This point is slightly, is probably more generic over the whole model, not just, it's not just located around the direct effect, but these, all of these effects are essentially interdependent. So what that means is that the energy return, for example, is not derived solely from the properties of the midsole. It has to, you know, One of the earlier studies on the Nike Vaporfly, for example, it showed the change in the stored energy. Sorry, the amount of energy that's actually stored and released is relatively small. You know, it's just a few joules per step. And so there's been a few people who have sort of suggested that this is not sufficient amount of energy to account for the changes that we see in running economy. So what the framework proposes is that it's not, it's not that the footwear alone can do that. It has to be this interdependent effect between the footwear and the biomechanics as well, the ankle and foot biomechanics and the characteristics, the spring mass characteristics of the leg. So if you change the footwear, the runner can't help but move slightly differently. And therefore you might move those differences in movements in combination with the enhanced technologies of the shoe would combine to improve the spring. Efficiency. Yeah. It's an integrated response. Yeah. Yeah, that's right. But it's still proportional to those differences in the properties. So the properties alone don't account for it, but they're, the differences are there. We, we, uh, studies are showing the differences in. you know, the energy stored, the energy returned, the mass, for example, the thickness, all of these variables are quite clear that reported in a number of studies that they do differ between these more advanced shoes in the last seven or eight years and the, and the old traditional type of shoe. Um, but the idea in this paper is that, yeah, it's this kind of integrated response. You mentioned the key differences, the key like components of this advanced technology being lighter mass, you mentioned the thicker sole, the midsole and also this inbuilt carbon plate. If you were to try and answer like, what do you think the carbon plate is doing? We'll go through all of them. But like, the carbon plate specifically, how is that making someone move differently? Or how is that? enhancing someone's running economy if it is at all. What do you think the mechanics are at play there? Yeah, so this is, the thing I should say about this article is that it doesn't provide answers. It's a way to generate further research in how we can view running economy and running and footwear in a different way. just to give a background around that and why we wrote this paper in the way that we did is that the original paper into the Vaporfly of course estimated a difference of around 4%. And so the idea, you know, the general idea is that it's the footwear that causes this 4%. But of course around that 4% what we know is that there's quite a lot of variability for across individuals. So that led to this idea that It's not the footwear, perhaps, that's causing that variability. It's the individualized biomechanics that's causing the variability. So there's been a fair bit of research over the last four or five years by a couple of different groups looking at what variables, which of the properties of the shoe, which of the technologies might be responsible for that individualized effect or the... Well... Yeah, this individualized effect. Why is it that certain people are getting a 6% improvement and others very little percent improvement for a given shoot? One of the possible mechanisms is the carbon fiber plate. That's one of the technologies that is likely contributing to it. And the estimate varies between perhaps half a percent up to just above 1%. between different studies and perhaps different standard of runner, different types of runner. But what the plate appears to be doing, or at least what some studies are showing, is that it acts to provide a more rigid foot segment. In doing so, it reduces the amount of energy that's being lost in the foot and the ankle. Running barefoot, for example, the foot obviously bends and flexes and extends. And in doing so with the tendons and the muscles stretching and contracting, a certain amount of energy there is lost to heat. And the idea behind the plate, the carbon fiber plate, is that it reduces the amount of energy that's lost in the foot and the ankle. So How it does this is not quite clear. That's, that's the other part of, um, the other part of that puzzle is it reduces or it changes the, the joint work in the, in the foot and the ankle. But what's not clear is, is how much of that is, uh, due to energy savings with, uh, tendon behavior or reduced muscle work. Um, so there's, there's quite a few things there to work out. One of the key things, though, is whether, for Rosalyn, this paper was trying to work out, is the plate itself part of that direct effect, or is it part of the indirect effect? And the paper sort of leaves that open, really. That said, I'm favoring more of the indirect effect. And one of the reasons for this is, first of all, its mechanism of action looks like it's more along that ankle foot-bound mechanics. pathway as opposed to behaving like a spring, for example. If it was behaving like a spring, it perhaps might be more along that direct pathway. The other reason why I think it's perhaps more on that mediated effect pathway is that the effect of the plate varies quite a lot with individual characteristics. So some of the earlier work on this There is body mass, for example, perhaps affects the extent to which the, uh, the carbon fiber plate works. So one stiffness, for example, won't work for every individual based on their body mass. Does complicate things. Um, I have had Simon Barthold, who is a researcher podiatrist on the podcast at the past, and he's worked with some big shoe companies and was talking about the carbon fiber plates. And how he described it was a lot of people see like a rigid plate and they think, Oh, it's probably going to just like spring me forward if it's more rigid. Whereas his definition or explanation of it was it kind of acts more like a lever. Like if you contact with your heel and you have a very rigid, long lever, that being the shoe and you plant that down, it's a little bit more efficient in terms of like moving you forward. Which I found to be helpful because it's, if you are a heel striker, which most runners are, that you would take advantage of that lever effect. Maybe if your foot, if you have more of a pronounced, or if your toes are a little bit higher up when you hit the ground compared to others, maybe that creates more of a lever effect. I'm not too sure, but I know for me, like most of my running, I contact with like a mid foot strike. And I could just imagine I've never been in carbon fiber shoes before, but if I was to run with a carbon fiber shoe and then try to elicit that lever effect, it wouldn't really have much of an effect on me because I'm not really contacting with my heel or having my toes in the air when I contact the ground. So then it's kind of like a null effect, which sort of leads to your point of these shoes affect people differently. If that theory is correct, I'm not sure if it is, but if we are having this foot... this shoe creating a lever effect, then it'll just depend on your foot strike, whether you can take more or less advantage of it. Would that make sense to you? Yeah, definitely. Yeah. I mean, that, that idea around it, you know, being a, the plate, uh, creating a more rigid segment there at the foot, you know, it's consistent with that idea of a lever, so, um, yeah, uh, and then there is the, um, Ben O'Nigg's research group, uh, I know that's one of them. The main theories I think from that group as well is that it acts as a leader. This call it the T Dottor effect in a number of the papers. So yeah. Um, yeah, I'd agree that that's fairly consistent. Yeah. And then that it's going to vary, uh, between individuals and not just body mass, but you're right. Um, the, the foot strike pattern, um, you know, Foot length, like length height, all of these things could affect is likely to affect them. it's, it's how it works. The other thing being with like that thick sole, I know like as foam technologies become more and more advanced, there's there seems to be more of a energy return to the runner. And when you hit the ground and the shoe absorbs the load that you put through it. know, a certain fraction of that actually bounces back up to you and actually returns energy to you. But with these changes in phones and that kind of technology, I guess that energy that's lost is becoming more and more minimal, that's then translating into something's, you know, spring, more springy underneath your foot or returning more energy, they then going to help your running performance and economy. Which then I'm thinking of the individuals, that's when probably how hard you're hitting the ground or your cadence and those sorts of things would all be individual parameters that might lead to that variability you're talking about. Would that make sense? Yeah, exactly. Yeah, definitely. And the cadence is one of the things that affects the spring mass system as well. So it all sort of comes together. Right. Is there a way that someone can look at how they're running, look at their own mechanics and then see what sort of framework or what type of shoe or what type of technology might take, they can take more advantage of. Is there a way to do that at this stage? I'm not aware of any formal system of working out how certain type of shoe may be suited to a certain type of individual. I mean, there are some general heuristics around a race shoe being, you know, in the current context, a race shoe really has to have these advanced technologies to be competitive for a runner to be, to be competitive. Uh, for the recreational runner, um, though it's really comes back to the, to the, probably to the comfort of the shoe, you know, the comfort and, uh, how fun it feels to, to running the shoe. Um, there's. Certainly the framework currently, the framework is there now as a starting point in a way for to try to understand that individualized effect, to try to separate it out. So I'm not sure the research at the moment, whether we can really be that confident about saying a certain runner with a certain body mass, a certain height or a certain cadence could be suited to a certain shoe. I am aware of ASICS. I think ASICS is certainly one company that I've attempted to develop different shoes for different types of runner. So they've got their metaspeed range, the sky and the edge. I think it is the metaspeed sky and the metaspeed edge. One of those is suited more to a, or the idea is that the marketing is that it's directed more towards somebody who's got a longer step length and and the other one more towards somebody who's got a higher step frequency. So I'm, but I'm, I don't know if there's any research published on that. Um, so I guess a lot of that is internal research, um, on their behalf. Um, so I'm, I'm not too sure, but yeah, more, more generally, um, I'm not aware of any, unless you are, and we can talk about it. Not, not that I'm aware of, no. Um, and a lot of my advice is exactly what you said, sort of like, uh, falls back to comfort, uh, the unfortunate thing with that advice is you have to try out a bunch of shoes first and then. see what you gravitate towards and what you don't and, oh, what's more comfortable, it's less comfortable and taking advantage of that. But like, my point was when it comes to the lever effect or the cushioning and that sort of stuff is, like, we don't know unless you try it. And all of this is kind of theoretical in a way, like when I'm talking about the lever and, you know, pushing you forward, if you have more of a heel strike, like there's no, I don't think Theoretically, it makes sense. That's when probably the individual runners need to give it a go and see what effects it has for them. Yeah, that's right. I mean, it's just a trial and error, I guess. But over time, I suppose one gets, with practice, get used to understanding how a foot feels on, how a shoe feels on the foot. And you get better at being able to determine. what type of shoe is suited to you, I think. Do you have any advice for runners who want to try to become more economical, more efficient with their running? How can they measure their own running economy? Like if they have certain two different types of shoes, they want to know if one's more economical than the other, are there certain tests they can do or something, practically speaking, without going into a lab to know which one is right for them? Um, it can be challenging given, given out of a lab context, because it's, it's challenging to control for all the different variables, you know, if you're running on the road, you've just the changes in temperature, for example, will, will change, um, your economy. So, um, one, one thing, I guess the closest you can get is using a heart rate monitor. Um, that would be, that would be one way to go. Um, and using, if you can. find a relatively flat course somewhere that's, you know, it can probably 10 or 12 minute loops, something like that. And you'd have to do maybe repeated measures of, in each shoe with, on this same course and try to get the same time of day, the same conditions with regards to your nutrition and hydration. Just try to keep everything as controlled as possible and then run three or four times in each shoe under as similar conditions as you can get. And seeing if there's any systematic difference in the heart rates for each shoe. That will be because heart rate is at submaximal intensities, as we said earlier, you'd have to go at submaximal speed. So again, you're trying to keep a consistent speed for each. each trial as well. Um, but which, you know, which can measure using, you know, your GPS watches and that type of thing. Um, yeah. So heart rate correlates pretty well to, uh, to oxygen costs when running at those submaximal speeds. So, yeah, you could use a heart rate monitor. Good to know. I'm thinking of like, if we're talking about terrain and conditions and that sort of stuff, I'm thinking about like an athletics track. Kind of. running around an athletics track, same time of the day, hopefully same temperature and weather conditions. But, okay. So I've got my watch and I'm going to run for, I don't know, 30 minutes. And I try to keep a consistent speed. So I've got my watch set to, um, like real time pace and I'm trying to keep the same pace for that 30 minutes. And then I'll do that on another day, ideal conditions, different shoes, do the same thing and. see if my heart rate is lower for one shoe compared to the other. Theoretically, if we do this repeatedly time and time again, and consistently, my heart rate is lower, running that 30 minutes at that pace around that track, that shoe would be more economical because I'm using less oxygen because my heart rate's lower. Am I on the same page there? Yeah. Yeah, that's right. If you've got access to a track, even, even better. Um, you know, you, yeah, that's, that's for sure. Um, You know, the, the distance that you go or the duration, um, I'm not sure it has to be 30 minutes. If that's just a regular run, if that's just a regular easy run, then, then that's fine. Um, but, uh, but anything that's longer than a period of time where you can, you can get just a leveling off of your, of your heart rate. Um, so yeah, that would, would be sufficient, but yeah, 30 minute run would be fine. I thought, yeah, I guess in saying that it could be five minutes and then you can swap your shoes. out every time. Like if you had, if you had shoe A and shoe B, one week I start with shoe A and then I do five minutes and I go to shoe B, do five minutes and swap, I don't know, six times. And then next time, same time of the week, I start with shoe B and then I stopped to shoe A. And then I keep going around the track, keep gathering data, and then look at my heart rate data after the fact and seeing if there's any consistency in terms of lower heart rate, then I'm on the right track. Yeah, absolutely. Yeah. Five or six minutes should be enough time running at a constant speed. If you're able to maintain that constant speed and not vary too much, um, that should be fine and then repeating it. Like you said, and then reversing it, um, is good too. If someone's training for a marathon or wants to train for a marathon and they want to do it the fastest way and the fastest time possible, if they're shopping for a shoe, What would be your recommendation based on what you know? If they're racing a marathon as fast as possible, the advice, current advice based on the performance of shoes will be to, to go for one of these, um, for a shoe that has some of these advanced so-called advanced technologies. Um, that said, there are, there is quite a bit of variation actually within, within those shoes, a study published a couple of years ago, they tested, uh, think it was seven different shoes across the different manufacturers. Uh, they found quite a lot of variability there. So all of these shoes are not built equally. There, there is still quite a bit of variation even within that category of shoe now. So, uh, so again, it probably comes back to that individualized effects, how, how good a shoe feels, the comfort. My suspicion is down the track that comfort idea actually relates anyway to in some way to economy, you know, that there is a connection there. Um, so, so we cut using comfort still as that guy guiding, uh, principle, I think, because if you're running in a shoe for hours at a time on a marathon, it's gotta be a shoe that's comfortable. Um, and, uh, and he's, he's therefore less likely to cause injury, um, down, down the track. I'm familiar with that paper. I think it was like the Nike Vaporfly, which was top of the tier with an economy of around about 4%. Unfortunately, it's like the most expensive shoe. I don't know if much has changed since the release of that paper, but probably goes to say, like you say, every shoe is different, maybe with the different foam technologies rather than the plate itself. I'm not sure how different the plates are between the shoes. actually not too sure, but I do know that from talking with Simon, it seems like these companies that keep their foam technology is pretty secret, like within the company itself. And I think they tested a couple of Nike shoes in that particular study and they both, you know, performed quite well. So they're probably keeping that quite secret and putting them in obviously in those two different shoes. I think the Alpha fly and the Vapor fly were the two that were in that paper. Um, so yeah, I, like I said, I'm not sure. I think that was a couple of years ago when that paper was published. I'm not sure how much has changed since then, but people are getting faster in those shoes, it's pretty undeniable. But like you say, there's variability and so testing is required for the individual itself based on their own individual characteristics. Yeah, and just throw another one in there. I think it's not just these technologies themselves, the plate and the foam. It's also the geometry of the shoe, so that the heel to toe height difference, the shape of the footwear. As you mentioned there, the shape of the carbon fiber plate, which varies, it does vary quite a lot between manufacturers and between shoes. The width of the shoe is another. Another factor that comes into the comfort category, I think, as well. The upper as well, how well fitting the upper is. So I suspect that, to come back to the paper, that a lot of these types of variables to do it around the geometry are, again, along that mediated effect and how they affect the function of the foot and the ankle, as opposed to those things affecting directly the springiness, if you like, of the footwear. Yeah. So, so, and that's, I guess, one of the reasons why the comfort feeds into that, into also that mediator effect. Is it, I know this is outside the scope of the paper, but, um, do we have any risks when assigning a new shoe and running racing in a new shoe, if someone goes out and buys one of these super shoes, um, is there any like words of wisdom or how we can transition into them safely? Um, I'm probably move, this is your area, isn't it? Yeah. A little bit. Yeah. My, yeah, I've been, I've been a runner for a long time recreationally as well. So I understand. Um, these changes in shoes, I've tried lots of different shoes and, and yeah, that my own experience is that even shifting between manufacturers can, can cause, you know, some changes in your biomechanics that if not caught early enough, can lead down the, down the path to, um, to various little niggles that perhaps needs some rest and recovery before you can carry on. So, uh, I think any major changes in. in footwear type from say a traditional shoe to a more modern performance shoe or changes from let's say minimalist or too minimalist footwear, I think all would require a certain amount of moderating of the volumes and speeds and gradual increases until you can get back up to those, to the volumes you're perhaps doing in the other shoes. Um, I don't know about your, what were your, you know, I remember the, the barefoot or minimalist, um, trend of, of running that's been around for, I guess, for, for quite a while now. Um, but whether a certain amount of injuries early on was associated with trying to increase the volumes too quickly. Um, I don't know what your thoughts on that one. Yeah. Usually when it comes to footwear. and changing footwear, I like to tend to think about like how different is it from the shoe you've already adapted to and how different it is. And you can use like, you know, there's a minimalist index or something along that effect, but how different it is compared to what you're used to, we need to, the more different we need to be more conservative with our transition. And least often like a lot of people just By the exact same shoes, just a newer version of what they've been running in. It's like, well, there's not a lot of difference. We don't have to be as careful, but sure. You can, um, work it in 50 or working for a few days or just to your shorter runs and then transition within a week, but there's been a few studies about, um, just recreational runners transitioning into barefoot shoes. And these are the guidelines to follow. This is the transition period. No one followed the transition period. And like. 85% of the people in the study got injured. And that was like stress fractures of the foot and, you know, most injuries below the knee and it's like, okay, but that's going from a people running in traditional running shoe to like, minimalist, like barefoot shoes, as minimalist as you can get to without running in bare feet. And so there's a huge, huge difference. And so a lot of time needs to be taken, you know, transitioning into that. So these super shoes are just like, completely foreign to a lot of people like they run in and they feel different, they feel like they're moving different, like the stack height is different and the bounce is different and the weight is different, like there's a whole bunch of different things with characteristics within that shuri and if it's completely foreign to what you're used to, I do think a transition period, a careful transition period is necessary but listen to your body, see if that transition is more or less, we could probably, if that transition is too quickly. We can usually pick up on it quite early if you're really listening to your body and then just adjust accordingly. But a lot of people don't want to do that. A lot of people want to, you know, spend $400 on a super shoe and then go out and run and run 20 Ks and run really fast. And then unfortunately that opens up the risk for injury. Um, so yes, I do think caution is advised. Yeah, definitely. And I think they can be, it can be quite misleading because of the stack height sometimes with these shoes, the more modern performance shoes, they do tend to be thicker in midsole and if someone isn't used to that, at first I guess with all that cushioning it might feel like you've got quite a bit of protection there but what comes with that sometimes is a little bit less stability and particularly at the back of the foot where the foam, where the thickest part of the foam is and with that lack of stability you might get some extra movement that you're not used to and And so, yeah, I'd agree. It's, it can be, um, can be deceiving, I think, with those shoes. Yeah. We're running a study at the moment, um, looking at differences between these shoes to try to put some evidence around this, this framework, uh, to see if some of the, the points, uh, some of these pathways stack up and, um, a number of people have commented to, uh, not used to maybe running in the super shoes previously. Um, have commented on, on some of that instability around the, the heel in particular. Gotcha. Yeah. Are there any other practical takeaways or insights within this paper that would benefit a recreational runner that we haven't yet discussed? Um, I don't, I don't think we, I think we've covered everything that I across the what's relevant to the paper. Um, I think it probably just comes back to that second half of the. of the discussion really around, it comes back to the enjoyment and, uh, and safety and, uh, and comfort. So what, whatever is comfortable, whatever makes running fun, um, and, and making changes be conservative. If you, if you are transitioning to us, to one of these, uh, more modern performance shoes. Um, and, uh, but then, then again, have fun. I think runners definitely need to be reminded of that a lot. So. I'm glad. Is it like future directions? Like, do you have any ideas of, I know you say you're just currently working on a new paper, kind of putting this theoretical framework into practice, but anything else on the horizon in terms of interests or research directions that you might take? Um, well, this is one focus at the moment. Um, there's a, we've got a couple of studies that are ongoing. So there's still data collection is still, it's still ongoing for those. So the paper will come eventually, but it will be, uh, could be a little while before he gets out of there. Um, I haven't looked too, too much far past, past this one yet. So we have to see what, what the results are from, from this study and, and go from there, but I would love to carry this on. I would love to continue along this, this line, but it depends of course on the. Things like funding as well. Definitely. Yes. I know it's a tough business, but, um, if you ever like when you, when you do end up releasing this paper and getting the findings, um, if there's something that's really interesting and relatable to recreational runners, I'd be happy to jump on discuss, um, I think taking something that's theoretical and putting into practice, then getting some good information, uh, is really useful to put out there. So. Um, I'll try and stay in the loop with that one, but like you say, I know it takes a long time to eventually work its way to getting published. Um, but I'd love you to come back and come on if there's any, anything that comes on and is released in the horizon. Yeah, great. Thanks, Brody. That's much appreciated. Um, I'll be sure to send something through, um, when we, when we, if and when we get something published from this. Excellent. Thanks for your hard work. Uh, thanks for coming onto the podcast and sharing all your insights. No problem, Brody, and thanks for having me on. If you are looking for more resources to run smarter, or you'd like to jump on a free 20 minute injury chat with me, then click on the resources link in the show notes. There you'll find a link to schedule a call, plus free resources like my very popular injury prevention five day course. You'll also find. Run Smarter book and ways you can access my ever-growing treasure trove of running research papers. Thanks once again for joining me and well done on prioritising your running wisdom.