Episode 425: The Hunt for the Best Super Shoe with Dustin Joubert

Dustin Joubert is a running researcher, PhD in Exercise Physiology and professor at St. Edwards University. He has a popular IG and website that deep dives into super shoe technology. He also runs a lab in Austin, Texas where he tests both running and shoe efficiency.

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Timestamps:

00:00:00 Going Unsponsored: Shoe Choice Freedom

00:06:23 Evolution of Running Shoe Technology

00:12:44 Understanding Foam Technology in Running Shoes

00:19:13 Testing Shoe Performance: Methodology and Insights

00:25:35 The Impact of Super Shoes on Running Economy

00:31:59 The Effectiveness of Shoe Testing

00:37:53 Evaluating Running Shoes with Expert Insights

00:44:13 Evolution of Super Shoes in Competitive Running

00:50:45 Understanding Shoe Performance in Marathons

00:56:51 Impact of Terrain on Running Efficiency

01:03:39 Shoe Efficiency Trends in Men and Women

01:12:03 The Rise of Wearable Tech in Running

01:16:17 Evolution of Control Shoes in Running Research

01:22:27 Analyzing Economy Benefits and Running Performance

01:28:48 Evaluating Sports Tech Gadgets

01:35:09 Understanding Running Economy and Super Shoes

Episode Transcript:

Dustin, thanks for coming on the show. Yeah, man, I'm excited to talk with you. Yeah, I'm looking forward to diving into this topic. It's an exciting year for me because I chose to go unsponsored for the first year in 11 years. So I have my pick of the lot, as they say when it comes to shoe choice. And I think that that might be almost a necessity to some degree nowadays, with the options we have out there and how people respond to some of the different products that are available. Yeah, I mean, it's an exciting time for that to have that option, right? Like to be locked in and not be able to try everything. Yeah, yeah. And I kind of can relate in the sense not as a, not as an elite athlete who has shoe sponsorships, but as a researcher. I've stayed independent of the shoe companies, and that's been a really fun thing to be able to do, because I can ask the questions I want or the questions that, like normal runners and consumers might want, as opposed to questions that maybe are driven by the shoe companies themselves. Yeah. Do the brands reach out to you, though, just knowing kind of what you do. So like, I, I have some relationships with like, you know, like, The like, the product line, like the performance line guys at different brands, but not not in like a hey, let's do this research study together. Sure. So it's like there is any conflict of interest. The shoe companies traditionally have always been interested in working more with things like biomechanics. So they got all the motion capture stuff and the horse measuring treadmills. And my background is as an exercise physiologist. So like with the new super shoes, the big thing is measuring running economy or, you know, oxygen costs. So I've got the metabolic cart like top level metabolic rate in my lab and stuff to do that, but less so much like the motion capture and all that. So, traditionally, I feel like most of the labs that are funded by shoe companies are kind of biomechanics tech folks. And so that's one reason. And then the other reason I, like I said, is like kind of being able to look at the questions I want to look at, you're not going to be able to do a brand of brand comparison with this study that's sponsored by a shoe company, right? Right, right. Yeah. Yeah. I'd be curious to see like over the or over the years or in the coming years, if it's just something where they, they almost value the third party unbiased look because I mean these, these brands all have their claims, right, of like, oh yeah, 95% or 93% or whatever it happens to be. Right? But everyone probably looks at that through the same lens they do marketing if it's coming from. Yeah, exactly. I think that's the point. It's like if you look at the original Vaporfly 4% study it is like that was groundbreaking and you probably wanted a third party lab to put that out there, right? Yeah. And not just like having your own company claim for it, but then it's like, is it worth it to do that every time you have a release of a shoe? Or can you rely on the marketing that comes from, like, you know, influencers and stuff, right. Yeah. Like even, I think I was thinking about this, The so like the three years ago now like the original supergroup study I did was like comparing multiple brands. And those are all like first iterations now. So it's dated, right? Yeah. But like that paper is probably like most, most downloaded red paper like I'll ever publish in my life. Like the preprint of that paper has been downloaded like 50,000 times. But if you compare that to a big social media influencer, right, they'll get that on like a single reel, right? Yeah. And so it's like, yeah. When you think of what the brands would want to invest in a published research study or like influencers who can share right away more mass marketing content, like there's it makes me think of when Adidas launched the $500, what they call the single use shoe. Yeah. And it was funny because it was like, yeah, like a bunch of them there was like only like I think maybe 500 of them were made originally. Anyway, I don't know what they did with it eventually, but it was fun to watch and see who got their hands on a pair of those. Oh yeah. And it was very strategic. You know, they want and I think with something like that, it's almost like you make a shoe like that, I guess, like you could sell it, but you could also just take bits and pieces of that. What made that shoe and put it in the rest of your models that you're going to sell more generally to the public and say, hey, this is the midsole from that shoe or the outsole from that shoe. And yeah, kind of use the marketing to drive different aspects of it. Yeah, and you got to figure in any of those, like top tier racing shoes. That's still like such a small percentage of those companies, like, revenues probably. So it's more like having that out there and elite athletes wearing that and the brand image that comes with that. Yeah. Yeah. Yeah I tried I didn't get the initial release but then there was like a random release like maybe almost a year after that. I got my hands on those for a bit. So I did test those in the lab. Yeah I own a few people. I didn't keep them. Yeah. Yeah. I want to get into kind of the variance. but then I also I it's one of those things too now where like, if you look at a pro athlete and you like, you'll see a record get broke or something like that, or like the most recent example of Connor Manns breaks the American record and the half marathon and you're like, oh, well, she was wearing well. It's probably a prototype that they got through the World Athletics like verification process and is maybe not quite ready for the public yet. Is that what you see generally or. I mean I think there's a lot of records now that have been said, and at least shoes that are now available for the market. Right. The world Athletics rule is like I'd have to look at the exact language of it. But like if it is a prototype, it has to be something that's going to be released within a certain number of months. And I think it's a little wishy washy on exactly what that looks like. But, Or like they'll have a small release so they don't break that rule. but I'd say my take is that most of the technology that's breaking records is at least stuff that, if not already on the market, will soon be on the market. I don't know if they have such a long time. So yeah, there's like such a breakthrough prototype thing that no one else exposed. Like early on when we had, you had like everyone running in 4%. Right. Yeah. and and people like, you know, spray painting their shoes and things like that, like, I don't think we're there anymore. Yeah. I guess before we get into the weeds, we should probably just let everyone know who you are, what you're up to, what kind of got you into this side of the world with shoe testing and things like that. So what was your, like, original launch into, the shoe testing type of stuff? Yeah, yeah. So my story, you know, lifelong runner, mediocre collegiate runner that was injured all the time. always interested, interested in sports science and, like, how to be faster, right. so that kind of led me to, like, PhD and exercise physiology. I was always interested in endurance performance. And, Yeah, 3 or 4 years ago I got into like, more running economy. So, like, measuring oxygen consumption, energy expenditure in the lab while people are running at a fixed speed to, like, determine, how much energy it takes to run at that speed. And that kind of became our research focus the last few years. But, kind of, stimulated by the release of super shoes. So this is, you know, what, 2016 you got Rio Olympics when like, paper flies come and see. And so until that stuff's really available in the market 2 or 3 years later, like is when I started testing stuff like that in my lab, and I was interested in, you know, at the, at the time, it was like all the podiums at World Marathon Majors were, you know, Vaporfly 4% shoes and, I had, I had picked up a pair of what were the Hoka Carbon X, I think like the first iteration. And I was like, okay, carbon plated shoes. And like I could feel the stiffness in it, right? And like, I trained for a marathon in those and that didn't have a great marathon. Probably more on me than the shoe. But, then I was like, I was about to buy a second pair and the alpha fly was out at this point. the original original flight. And, I was like, well, before I buy a second pair of these, I go, like, test them in the lab. Right. So I tested my original Hoka carbon Plate shoe against just like a regular old flat in the lab. And like, my running economy was the exact same, and the regular old flat and that. And I was like, okay, am I a non responder? Right. This term has been thrown around. or is it the shoe. And so I then I picked up the fly and I was like 4% better fit right out of the box. And I was like okay this is something different. Right? Like originally that just played in the shoe. I could feel the stiffness, but then like, yeah, that original flight like this is something different. And so yeah, so that kind of sparked the interest in doing a brand comparison. Yeah. and so that's man what is that that's. To lose track of years. I was like 21 wins though. Yeah. That study I think we got out 2021. Yeah. Yeah, that's one of my biggest kind of like I wish we could go back and see again. Stories with that launch of Hocus first one, they did that whole thing like, what was it, was it carbon X I think was a project. It was a 100 K race. So they had like a bunch of their ultra runners out there. And Jim Walmsley was going for the world record for 100 K, which at the time I think was like 609 or something like that. And he ended up falling like 11 seconds or 9 seconds shy of it. And everyone's like, okay, well, this is a super shoe. What would he have run in a normal shoe? And then once we get all the research, how it turns out, he was basically probably running in the control shoe and he's like, I wonder what he would have done on a vaporfly. Maybe he goes, yeah, closer to low six six hours maybe. Yeah, I definitely think I mean, that's you and I haven't tested the most recent iteration. They didn't think that that shoot still had old Eva foam. It was like a flat plate. not much of a rocker on it. Whereas I think the newer iterations of Hoka Super Shoes have got people foam in there, I think on the new ones. Yeah. Yeah. So I'd expect those to test better if we, if we redid that kind of study again. But yeah, definitely. I think athletes who were in that shoe at that time are probably definitely at a disadvantage. Yeah. And that's and that is that's not just from my personal data. That was like the first study we did. We had 6 or 7 different super shoes in the lineup, and that was one of the ones that was kind of a dud, that it was equivalent to the control shoe, like across the whole group. Not just not just the individual person. Yeah. And you wonder how much of that is just, you know, Nike kind of comes out a little bit under the radar at first. Like, I don't know how available the information of what they were working on to other brands seemed like none, essentially. So they launched that shoe. And then it's sort of, okay, we got to catch up here. But when you look at just shoe design and how that ends up playing out, you're usually looking at 12, 18 months before you can take a shoe to market after the kind of the first prototype. And when you're talking about something that high, kind of that super shoe foam, you know, that a new invention, essentially, it's just like a crazy catch up time frame. So I just wonder sometimes when brands were coming out with their first models, they were just trying to get something to market as quickly as they could to have something, and then hoping to build off of it over the years and try to catch up to Nike, essentially. Yeah, yeah, I bet that's probably fair. I mean, without talking to the product line guys with individual companies, I'm sure some of the bigger companies probably had their own R&D going on that was working on similar things. But I think if you just look at how the market responded to that, like everything was about carbon play, right? Carbon play, carbon play, like everyone just stuck in a carbon plate in the shoe. And that's what we realize is like the carbon plate alone is not doing most of it right. Like the foam was a bigger part of that story. and that's what I think has started to catch up across brands now probably. Yeah. Yeah. That's the other interesting thing too, because at first it was like pebble foam, right? Like that was the foam that was more likely to produce the better energy return. Am I right that like, now you're starting to see non-edible foams that are starting to catch up, at least in some circumstances? Yeah, that's the foam tech. And talking about the foam tech is tricky to me because saying something's eva something something's peba like that's the big distinction. But like how you take that like chemical soup and turn it into foam. Like, there's a lot of variation in the properties of Pebble. Like even within Nike shoes, like zoom that's in the invincible is slightly different from the zoom that's in their racing shoes. And so that's all Pebble though, right? Like, yeah. And you can make it like PE but that's like a hard plastic looking plate. Or you can make it this foamy cushy thing. So it's like I think there's a lot of chemical engineering and like the foaming of the midsole that you probably need to talk to shoe people, shoe manufacturer people, right to really get to the bottom of that. But I think, yeah, I think that probably does lend itself towards that. It's not just a single like Molecule or a single single like formula. That's like going to work in the best film, right? But, it's probably more complicated. Yeah. For sure. Yeah. It seemed like historically you could fairly reliably be with any of the major brands and probably find a shoe that as long as it worked with you reasonably well, it wasn't going to be like outcompeted by a large margin from one brand to the next. But now, like, that's not necessarily the case. And it's not always necessarily the case at the individual level either, where you get someone who just responds really well to a specific shoe, then someone's like, well, like, I guess maybe the way to look at this is like, say, Kipchoge goes and, you know, runs his sub two hour, project thing and everyone's like, well, that's the shoe I need to wear. But everyone who sees that they probably are right, that getting in a super shoe is going to improve their performance to some degree. But it may not be that exact shoe. It may be one of the other brands' models that they respond better to. Yeah, yeah. That's a tough topic. This idea of like individual responsiveness and like high responders, low responders. You know, I think some folks said when we did that first study, like comparing seven different brands, models like, oh, it's all going to be individual, right? Like everyone's having a huge response and like it wasn't the case in that like at that time, right? There were some shoes that were like top tier, mid tier, low tier. And that was a pretty consistent response. across people. That's why we're able to make conclusions of, or like differences. I think as other brands have caught up using some of the same materials like you talk about. Those differences probably have diminished, but there's not really like good published data on examining like, differences in magnitude of responsiveness across individuals. Like, I've got a lot of case study data and I've got, like, we do testing at my lab, like, we need to get you in the lab with all the shoes that you're testing. Yeah. And like, we can we can we can test you in 4 or 5 shoes in a single day, like, and and look at those numbers for you. and there was one study that came out that was like plus or -11% benefit. And like these different shoes, it was an Adidas backed study. And, they showed even within their Adidas super shoe prototypes like elite Kenyans. There were some shoes in that lineup that some of the guys were getting like 11% running economy benefit and others were 11% decrement. Oh, wow. Which is like a 22% swing, which is just insane. Like that's equipment noise. It's not. Yeah, that's not the level of individual responsiveness we're seeing. Like, so no one's getting a 10% benefit in a super shoe compared to a traditional shoe or another super shoe. For example, like in those magnitudes, like if I test myself in the alpha fly, which is like the best shoe I ever tested, usually like 4 or 5% compared to like my standard control shoe to a croc. Like your gardening clog. Right? That's like 8% difference for me. So, like to have a 20% swing is like, that's equipment noise. So some stuff got overblown with like, hyper responders in super shoes, like, okay. We've gone back. We've got. We've got a reliability study that's about to get published that looks at how consistent your metabolic card is. Like, it's making these readings, like how we're making these interpretations, like how consistent it is. And I feel confident, like in our lab with our equipment, like any difference is greater than 1%, like on a given day, between two shoes for you. Like, we can make conclusions on that. but we wouldn't analyze, like, our old group data, for them at our original study, if you just look like the amount of noise, in that, like repeatability, there's probably, like, most of the shoes we look at, you can't really say like, oh, that's a high responder. That's a low responder. Like if we did the study again that person might be like here today and here the next time. And like all that to say there's like I don't I don't feel like we have good data out there to say, like who is a high responder and a low responder? Okay, I feel good if I take you into the lab individually, like we can make conclusions on a given day in that shoe lineup to give you good recommendations. I can tell you what's probably a wash. but to, to be like some people are getting a 5% benefit in this shoe and others a two. And I think it's harder to make those comparisons so far. Okay. That's interesting. Yeah, my assumption was that it was much larger than that. But it sounds like that's a lot of I don't. I don't think the differences are nearly as big as people. People made like I mean, like when Chepe Nogueira ran sub 210 and people were like, oh, it's because you switched shoes and you're giving a 5% benefit now, like, I don't I don't think she went from, you know, when she was in the vaporfly and then went to the Alpha three or something. Yeah, I don't think so. Yeah. There was another phase change of 5 or 6% on top of that. Yeah. Some of us got to be her just getting faster. Yeah. Yeah. I mean people can discuss all the potentials for that. Yeah. Yeah. Well and that's the big kind of worry about it it seems. Is that there like whatever variability there is, if it's if there were like hyper responders and non-responders and things like that, then you have this situation where you add another variable to sport essentially that's going to select, especially when you get to the top tier where, you know, a percentage could be the difference between being first or fifth at a big race. And now all of a sudden the shoe could actually cover that sort of a difference. Yeah, yeah. I mean, I'm definitely a proponent for individualized footwear testing. Like, I think it's an easy enough thing to measure in the lab. So basically, like for people who are familiar to assess your running economy, its maximal it has to be below threshold. So like usually we go marathon pace a little slower, and five minutes on five minutes off alternating between shoes so we can get to a steady state option consumption in that five minute window. We usually like to test every shoe and duplicate it. So like if you came into the lab with four shoes, we'd do eight reps by five minutes on, five minutes off and measure your oxygen consumption at, let's say, around marathon pace. Okay. and then we could compare the oxygen consumption or energy expenditure like between those different shoes. We average across the two trials. and so. The testing itself is not. It's not that complicated. Single day sub maximal. It's not like you have to come to the lab, get your finger pricked a bunch for like, lactate testing or, like do it all out. Max effort. and it's a single day in the lab, so, like, I mean, we do it in my lab for 60 to 80 bucks. and so it's. Yeah, if you're, if you're a competitive athlete, elite athlete, like, it's an easy thing that's on the table. Now, the harder thing is, like, to have the shoes in the lineup to come in. So, like, sometimes people, sometimes people like, buy a couple shoes, come test them in the lab, wipe them off and return the one that wasn't in the test. Good for him, right? Like, okay. I mean, so yeah, I think that if you're like, you know, a highly competitive athlete, that's maybe low hanging fruit. Not that hard of a thing to do. You just need a university lab with a good metabolic cart. then had to be a university lab, but most likely the place you find it. Now, there's different metabolic carts out there that are noisier than others. So when I say like I feel confident with, like, if I test you in the lab and we have more than 1% difference between two pairs of shoes, like I'd be confident in the conclusions I give you. That's not going to be the case on every metabolic cart. Some, like you, might need a bigger than 2% difference to be confident about that. Okay. Interesting. so that's why we had that like repeatability study to kind of establish what your equipment noise is. this? What level of consideration is there to fatigue coming in or throughout? Because like one thing I always think about is like whatever you test most efficiently in the lab, assuming you're relatively fresh. Is there a reason to doubt that that is sustainable over the course of a marathon, or is there? I guess maybe what I, what I would be interested in would be. Is there any reason for someone to go into your lab test fresh, and then go in again and test fatigue to kind of see if there's a difference between, say, the beginning of the marathon and the end of the marathon. Yeah. Yeah. So I think there's some speculation, and I've even seen a little bit like preliminary data that might suggest late in the marathon, tired legs, that the benefit is slightly greater. Like a super, super, say a control shoe. Would there be some interaction or crossover to where like this was your best shoe fresh and all of a sudden it's a totally different shoe. Yeah. Like when you're tired I would think more so like a better judge of that would be like hey, if we test you fresh, this is your best shoe, but you don't feel like after you go run two hours in that shoe that, like, you can do that, right? Like that. You can't take that shoe, that distance. And that's probably more of a sign, right? Like, but assuming you can run that distance in the shoe, you test fresh in most economical conditions. then. I doubt we're going to see a big swing like what's the best shoe later. But in terms of like, is the benefit greater on tired legs? I think there's a little bit of anecdotal evidence for, And we were talking about Jeff Burns. He's done a little trial stuff like that on himself, but nothing came too conclusive. But I've seen a little bit of preliminary like conference abstract type data that, that, that is, indicated maybe like the you're running economy gets worse the longer you run. Right. If we measure your run economy fresh versus tired, your energy consumption is going to go up as you get more tired. and so that drift up might be a little bit reduced. Okay. With the super shoes. Yeah. but I don't. I don't see that as needing to, like, maybe have to test you on tired legs as opposed to fresh legs because I just, I don't get the sense that the shoe that's best is going to totally flop. Totally flip. Right? Yeah. Yeah. I wonder because, like, I'm not doing marathons either. I'm doing a hundred mile races. So my other thought is always just like where let's say I got like three shoes that all tested within a percent of each other. From there. Is it just like, okay, well, this one feels way more comfortable on my foot. Am I probably going to want to lean towards that one, just given that I'll be on them for 11-12 hours? Yeah, I think that's fair. Then like I say if everything's a wash in the lab, then I'd say, you know, go for what you like. Pick what you like more or whichever one's got cooler colors or. Yeah. Right. and even when we test in the lab, I think we, you know, you're talking about ultra stuff, but, like, folks still have kind of this notion that, like, oh, if I'm gonna run A5K or a mile, I need, like, a more minimal shoe, right? And like, I want this high stack out, fly type shoe for a marathon, but not for A5K, maybe, like I got to do something lighter, right? Yeah. in my mind, like, you should race in your most economical shoe that you were comfortable in for that distance. So if you come into the lab and like, this big honking shoe is your most economical. my mind doesn't say. Just run that in the marathon. I say run that in all your distances. Yeah. Now, if you come into the lab in your most economical shoes, like some really lightweight, tiny, flimsy thing, right? And you're like, okay, I can run a mile on that, but I don't feel comfortable running a marathon on that. Then I say, well, pick something different, right? Yeah. But it's like, yeah, if you test most economically on a big shoe, then ride that thing. Yeah. That's the that's another interesting thing that I think about from time to time, because when before Super Shoes came out, when I first got into ultrarunning, my thought was, well, from a performance standpoint, you know, racing flats are going to be quicker than a nice cushioned shoe, assuming you can tolerate it. So I spent years building up my foot strength to where I did some 100 miles in like a 3.9oz shoe. Yeah. And when I ran my fastest hundred miler, it wasn't that small of a shoe, but it was basically a racing flat. Yeah. So. And I didn't have any love. I mean, I split the race and I was running my fastest miles at the end, so it's hard for me to argue that, like, you know what? If I like, like that, that was a limiter at the time, given that I wasn't running in super shoe foam. So I wonder if, like, there would be. I wonder, like with what you said. Like if you can tolerate the former shoe, do you still lean towards something or would you give a smaller benefit from a super shoe then? so you're asking like if you were already accustomed to, like, this minimalist shoe? Yeah. Would you be a lower responder essentially to this? Yeah, I think that goes back to like that responder non responder thing. Like yeah it's still an unknown like you know in our initial super shoe comparison study. I tried to look at some of those like who got the biggest response and Lee's response and like the folks who are most economical to begin with had a smaller response to the super shoes. But that's also just statistics. Because if you were, if you were more economical already than like, a shoe that gives you some benefit, like you're naturally like dividing it by it's like like it's, it's already baked into the percentage benefit, like, whereas if you were a really bad economy, then like, yeah, the super shoe is going to have a larger difference. So it might just be a statistical fluke and not necessarily like a responder thing. So, sure. I mean, I could see an argument though, like, if someone's already really economical, how economical can you become? Right. Like putting it, putting a new shoe on your foot, like, but I just don't know that we, like, have data to say that. Yeah. Confidently. I think it's been interesting in terms of like, when you look at the marathon in athletes who have scaled up to the marathon really rapidly, like from the track. Like, I mean, I think SFA was an 800 meter runner in the past. Yeah. I think, when you look at, what, Olympic champ female Netherlands was her name is. Oh, Hassan. Hassan. Yeah. Like going to a sauna is done like, like you wouldn't traditionally think like middle distance runners. Like the running economy being the most important, like performance determinant for them. Right. They could probably get by with a less great running economy. It's not like in the performance models the most important thing. Yeah. It's like running a marathon. You think running an economy is one of the most important things. So you , I sort of wonder, like this train of thought of like, oh, is it allowing people who, with a poor economy like, scale up to those longer distances better? Like, I, I like that kind of theory, but it's a hard thing to test out. Probably. Yeah. so, so to I guess to your question of like, you know, would you because you were already training in that more minimalist shoe, maybe had better economy get less benefit? I, we don't know. I guess unless we test you. Yeah. We'll have to find out. Yeah, yeah, yeah. It was funny because I was thinking to myself, I was like, I spent all those years trying to create an advantage by being able to tolerate a shoe like that for a 100 mile race because, like, no one else was really doing. I mean, I shouldn't say that there were others. There were other ultra runners doing minimalist stuff. Yeah, but there weren't other alternatives. Doing kind of the flat, controllable stuff the way I was. So in my mind, you know, I was chasing records, so I wasn't racing people necessarily. It was more like, okay, so-and-so ran 1128. I want to try to break that or I ran, you know, 1140 I want to try to get under that. And it was just like seeing, where can I kind of pull an advantage through, through that adaptation? But, when I think there's probably still a place for that adaptation and that like, as an aspect of training, right. Like you don't have to be all minimal or all maximal, right? Like the idea of, like, yeah, you probably shouldn't be running your shoes every day. You probably shouldn't be barefoot for life, right? Yeah. But like, there's probably still benefits to be had from like, jogging some minimal or walking around barefoot or doing some strides barefoot. Right. Like, I think we tend to make things like these opposite ends of the continuum as opposed to like this is a tool, right? This is a stimulus. Like, so yeah, I think probably like being in minimal footwear, walking around barefoot. There's probably some foot strength, like calf Achilles stiffness kind of stuff that might benefit from that. Is it fully additive to like the benefit of the shoe? I don't, you know, maybe not. But, I could see a place for all of those things. Right, right. That was going to be I've got this kind of conflicting two theories in my head that are maybe unanswerable, but I'll run them by you anyway. And one was just like. If you build up a ton of foot strength by running in a shoe like that, like a minimalist shoe or a firm shoe, and then you get into it like a super shoe. In my mind, I think, okay, you got strong lower legs. And now on top of it, you're putting this tool on there that's going to preserve that area better. But if I would say then just switch over to just training only in super shoes from there. Do I wonder if someone would have a better response to super, super early on and then over years, would that maybe diminish if they're not taking care of maintaining that foot strength they developed? My conflicting theory of that is. But they also may get more efficient in the super shoe by wearing it more often, and then therefore get better by having it and not have that diminishing return potential. Yeah, yeah. Yeah. So like what happens to your foot training. So that's not so much my research line, but like this is just from what I am from. Well from what I'm familiar with like the folks who do more of that. Like I think yes, we could make your calves and your feet weaker if we put you in a maximal shoe all the time when you used to be minimal, like, that would probably happen. and so that's why I think still, having some of that minimal stimulus is just good for all around, you know, injury prevention. you know. the question of do you need to train in the Shu to be, like, more economical in that Shu? I'm not so confident you need to do that. I've got a colleague who tried to tackle that in a master's thesis, which is a big, big take on to do a training study. Most of these studies are acute, like you come to the lab once in a single day, and, so he had people in a Super Shu in a control Shu test in the lab. Go out half the group. have the people trained in the Super Shu. Half the people trained in the control Shu. They came back. And so he was trying to track, like. Yeah. If you trained in the Super Shu, was that better or worse? and for the most part, it was. It was hard to make any, like, real conclusions from that work. but those who are doing training studies, like, are hard to do. You get people that drop out, people who don't come back to take your shoes. I get to keep all my shoes and lab tests because you only come in and test them once. But if you're doing a study like that, you have to send people off with shoes. That's like, right, tough studies to do. but yeah, no, I don't. I've done so much case study testing that I always go back to the fact that, like Nike, I'll fly for the first time out of the box 4%. And I've never gotten, like, much bigger than that. Or like, I, pretty much every day I've ever tested those. It's 3 to 5%. and so. I think there might be a little bit of a learning curve, like when you look at the biomechanics data, like people's biomechanics kind of settle out within the first three minutes or so of wearing a shoe. So like our little five minute trials that we do, even if you're wearing that shoe the first time, like you kind of settle into your mechanics pretty quickly. so I don't I don't know so much. Someone needs to go running it for months to, like, really get the benefit they're going to get out of it. I think your mechanics are just pretty quick. Yeah, yeah, you might just want to, like, use it in some of the training sessions that are specific to whatever you're doing. I like going back to principles like, we don't have to all become dumb because we have like, new shoes, right? Like back in the day, we would lace up our flats for, like, hard workouts. Like key sessions. Right. and then maybe there's some days we just did some tempos on in our trainers, right? Or did some heel reps and our trainers. It was just kind of like more low key, right? Yeah. And so like that same kind of mindset of like, hey, specificity is a good principle to follow. Like if this is a really key race pace kind of session, I want to mimic what I'm going to do in a race like, yeah, put the shoe on that. You're going to race in. Right. so it's like, yeah, I think for key workouts that make sense. even like, you know, in a marathon, training plan, like for your, your long runs with stuff in them. Right. Like when you're throwing in some marathon stuff. Like it makes sense to me. Maybe not on every single long run, but, on the ones where you're doing harder work in them. yeah, I think that's good, because you also want to know that you can wear that shoe for that long, right? Right. Yeah. Yep. Yeah. No. And that's how I usually go about it, because I'll get to the end of my training plan, and I follow kind of a I think all the training inputs are important when you're running 100 miles. So I'll be doing short intervals, long intervals and stuff like that, targeting VO2 max threshold stuff. But then when I get to the end of the plan, when I'm getting like, you know, eight weeks out from the race itself, I'll start skewing a lot of the training load to like longer runs at kind of race intensity. So by then, I'm starting to really get pretty particular about what product I'm using during those sessions, because I want to be really comfortable and know that that's the product that's going to, you know, get me to the finish line ultimately, too. And I think at that point, you know, you're probably going to be just fine in that shoe, if it made it through all those long runs. Yeah. Yeah I think that's a good philosophy. Have you, have you tried out the Mizuno Wave Rebellion Pro three? I've tried them on, but I haven't tested them, you know, so like but so my story from earlier, like I was, I was at Stephen f Austin State University out in Nacogdoches. Yeah. Up until I've been here in Austin at Saint Edward's University for two and a half years now. So when we first did that comparison study, it was SFA and that was so popular at the time. Like I was getting shoes almost weekly to like test, test return, test return kind of thing. And like had built up pretty big like social media following from that. Yeah. But like since moving to Austin, like I'm starting a lab from scratch here, which is up and running now like we got. I've got a good lab here now. can be as productive as ever. We've got a great, great, running community here to, like, bring in participants and do testing and, like the case studies, testing that that was done kind of fell off. So like a lot of stuff in the last year or two, like, I just haven't been liking buying stuff and testing as much. I have tried those on, though. They look pretty. I saw you were testing those out. Yeah. Yeah, yeah, they were probably the quickest brand to respond when I reached out and was like, hey, I'm going to be doing some shoe testing. Is there anything I should be aware of? And they're like, we should you should try these. Okay. So you are getting some brands to give you product now. Yeah. Yeah. Now. So what's your what's your take on. If you go to like objective right. So there's a lot of shoe review stuff right. Yeah. It's like just subjective. it's you can all boil down like, oh, it's just his opinion. Someone else might like it, right? Like, what's your take on if you get a bunch of stuff like this in the lab, go do objective testing and share it. Yeah, I think they're gonna care about that. They haven't. At least the brands I've been able to get contact with. They haven't seemed to care. They seem optimistic about just like, oh, yeah, we'll check it out, see what you have. I think, I mean, I haven't done any thorough reviews yet, so I could piss some people off, I guess, and they're like, we're not giving you shoes anymore. But, I mean, I think there's workarounds for that too, I think. I mean, you could partner with, like a running store or something like that. And, I mean, you could just buy the shoes as well if you wanted to go that route. Yeah. but yeah, I mean, I think it's like it's the way I look at it is like, if I'm getting if all the brands are going to send me their kind of like flagship offering and they're all kind of doing it, it's like, it's not like I'm getting better representation from one than the other. They're all giving me a pair of shoes to test out and create content with. And then it's like, I'm going to find the one that works best for me. But that may not be kind of like we were talking before. That might not necessarily be, the best for the next person. So I think as long as I'm kind of making sure that that's pretty clear, then I don't know that there's a huge problem with it. But yeah, someone will have a problem with it, I'm sure. Yeah, I know, I've I've kind of sat in a weird space when it comes to like the shoe testing. I never wanted to be like a shoe reviewer or YouTuber type of person. Right? Like my main. Position on this is academic, right? Like, I publish papers related to running performance, but like, I've had fun doing case study testing like on myself and sharing some of that on socials and stuff. Right. and, but at the same time, like, never really wanted that to grow into, like, that's my main avenue, right? My main thing. So like, I've kind of sat in this weird place of, like, not reaching out to like, because because there's a for for for, like what you're doing now. Right? There's like the marketing brand people. Right. Yeah. That is like kind of with the shoe review or influencer kind of folks. Right. And then like if you want to do the research though, then it's more of like the product line, development folks. And so I was kind of sitting in like a weird spot in the, in the both. Yeah. Yeah. Yeah. It's interesting. I mean, I think I have a review partner to do, you know, Brady Homer, by any chance? I know of Brady. Okay. Probably been on some long runs. Brady was on. Yeah. with the Purple Dragon crew, but, I, I'm Brady and I ever talked. I read Brady's content on Twitter. Sure. Yeah, yeah. So he's gonna review shoes for me, too. So my hope is that, like, we'll probably be different. Well, I mean, he's training for different stuff too, but I bet we'll have different preferences. So my hope is that something like that will show me where he'll be thinking about some things that he likes or doesn't like, and maybe I'll have a different experience. So we have some of that kind of variance there too. So it's not just like me saying what I like or or I mean, honestly, the way I kind of do it is like I don't think like most running shoes have a purpose. It's about figuring out what that purpose is and then, like, who it's likely to work better for. And when people listen to that stuff. Like, if I were listening to someone going over products, I would want to. I would want to just kind of have a similar experience as if I went to a specialty shop and they were like, oh yeah, what's your foot like? Okay, well, we 'd probably be better off in one of these four shoes out of the hundreds that they have there. So then they're helping you narrow that down to like 3 or 4 pairs. Then you try them on and see what works. So my hope is, like these people who are buying online or who are just shopping in general, they can say like, okay, well, I have no clue what I want. Now I've got it narrowed down to a few pairs, and then it's sort of on me to kind of put them on and see which one feels best. Yeah. That's where I would like it to go anyway, so we'll see how well the job I do at that. But yeah. And I've always thought too like the shoe review too, if you find somebody who. Kind of like, oh, they really like this shoe. This shoe really worked well for me. And they like this one too. So I bet that, like, if you kind of can find that in people, like, so if you get a little bit of diversity in opinion, so people kind of have that to pull from. That's one of the goals. Like all the case studies, testing I was doing originally was just pretty much on me. One of my goals when I came to Austin, got my lab set up, was to have like a small batch of people who, like, consistently came in like, so we did that a bit. When we got there we got the $500 Adidas shoe. You had me and two other folks that we tested. Now, we didn't all have the same full lineup because like, they were, some different other shoes. They wanted to test like that they would consider racing in. But we all had at least that Adidas shoe like in the lineup, you know. and so like it's kind of some small batch case study, testing like that to add to your kind of subjective experience, like to have those objective numbers. And then you can say, okay, well, this shoe is the worst for everybody. Or yeah, this one was better for him, not him. And they kind of get at some of those comparisons we were talking about earlier. Yeah. so I totally invite you and Brad against the lab whenever. Yeah. We want to come in and stuff, so we'd appreciate it. Yeah, yeah, that'd be fun. Content. Yeah, I mean that it is an interesting world with the different products out there, but the different foams and stuff. But yeah, the Mizuno Wave Rebellion was an interesting one because it seemed like they were trying to, like, skirt the rules with that shoe a little bit, where I think if I remember the specs right, that bulb of foam is the best way I can describe it is like 61mm, which is like, well, past regulation because regulation is like 40mm. Yeah. But since the measurement point, I mean, this is something that I find odd, like World Athletics decided a specific point on the shoe that you measure for that 40 millimeter cross point. And it's like, I guess it's far enough back where they could just lop off the back of that. Yeah, yeah, yeah. That's interesting. Yeah, I noticed that too. yeah. You know, it seems kind of like some of the regulations are arbitrary. I feel like when the regulations first came out, it was like, oh, this perfectly allows the original alpha fly to, like, be within the regulations and, like, everyone innovate around those guidelines. So, yeah, some of it seems a bit arbitrary when you think about it. But, you know, the idea of like, is more foam better? There's, there's a paper or two out, like at that, like there's some folks in, in my field who are like, we don't need regulations at all. And some would say, oh, we need regulations. We should limit the like. And that was one of Jeff's arguments. Like the original, the opinion piece he wrote on this topic was, like a limit to the area for future innovation. Like so regardless of whether or not like more foam is absolutely better. It's just like, who knows what's going to be invented next? Or come up with next, like limit the area. Everyone's like working from somewhere. Yeah. So I could see an argument for that. And then, the folks who are like, oh, don't limit innovation at all. Like stack height is self-limiting. Like if you make an eight millimeter shoe like it's not it's going to be too wobbly. So yeah. So there is a paper I've seen, I don't know if it's published yet or just for the preprint of it, but it was from the Holcombe Group, whose original paper is like 4% guy that has more foam. Potentially more economical. Like beyond the 40. But if you, if you like, consider the extra mass that comes with that, it might be a wash. And so that was in that study. It was like having extra mass. If it's not, the shoes aren't mass matched, which in the real world she's not going to be mass matched if you got extra 20 mm of foam on the sole of it. Right. then it was kind of a wash. And then and then on top of that, you like, sacrifice some, like lateral stability and stuff. So, I can see both arguments honestly. Like, so do you really need to skirt the guidelines by making 60 at one point. Like, is that even useful? Like, I'm sure you know, I think some of those recent papers I saw would suggest no, it doesn't matter. But yeah, I think some of those have the intention of removing that regulation too. Like that's there's like some footwear manufacturers like, which is to remove those regulations just not have any. But I tested the Prime X, the Adidas is like everyone getting around the legal shoes, right. Like, yeah, that one is like by all rules, not within the limits. Right. It's like over 40mm at the point of measurement. and I didn't. I didn't test better in that than, like in the Pro two or bigger than, like the fly. So it's like, yeah. but that's, you know, it's still kind of apples and oranges comparison if you're comparing different models of shoes. Right. You really need like. That exact same shoe in 40 versus 60. Like, is there a difference? Right? And only like the prototypes can really do that. Sure. Yeah. They're they're getting into creativity at its finest. At that point. Wasn't the shoe that Kipchoge wore for the Sub2 project? technically illegal shoe. But they hadn't put the regulations in place yet. It was, like 52mm and two plates or something like that. There's so much stories about it now. I don't know what's real and what's not. Yeah, I think that I think that's that that's the the main one. as far as I know, we ran in like, what is what we know of the Alpha fly original Alpha fly. But I, I saw anecdotal stories and postulates and like, old sketches and stuff of like. Yeah. so, so, yeah, I guess we'll never know unless we cut that shoe open. But, I've kind of accepted in my head that it was like, what? We know. Okay. But, yeah, it's interesting. The two plate thing. I don't know if any one's got published research on it. Isn't the newest the prime X two? Does it have two plates? Adidas. New illegal. One has has two plates. I don't think the one that I have does. I think it's just the higher stack. Yeah. I don't know for sure if that one's. I just know that they. You're not legally not allowed to have more than one plate at this point when the whole conversation about. Yeah, yeah, it's it's like 40 millimeter stack, one plate in a single plane is kind of the main thing, right? But for most of us, I mean, if you're competing like professionally under world athletics rules, elite athlete, that matters. But for most of us, it doesn't. You just want to go get that Boston ball somewhere. Someone going to basketball or even someone running and going run 225 at Boston. Like they're not in the, you know, pro field doing that. They can go wherever and shoe they want. You know. So yeah. Yeah. So you get that I guess too. So yeah. Yeah it's interesting when you think of just the different designs you could come up with and how you would work within the rules. I kind of like the idea of having some parameters and saying, okay, everyone builds within this. especially since apparently these brands have enough money to still build shoes outside of those rules if they want to play around with that sort of stuff. But yeah, it would be interesting to see because it's like you said, there's a diminishing return somewhere with any of that. So do you limit actually figuring that out by limiting the types of products? Obviously if they had no regulation, someone would be making a 60 millimeter shoe, and then someone like you would be out there testing it and seeing if it was better or worse or the same. Yeah. Yeah, I, I find myself more and more now on the like less regulation in the end if they just because it seems like it's like. It's already like that. Cat's out of the bag. Cat's out of the bag. Yeah, cats out of the bag. Exactly. to where I think, like, people ask me, like, what's going to be the next big thing, right? And I'm like, I'm not on the R&D side. Like, I can't tell you what's the next big thing. But I do feel like the big step change, the big phase change has already happened. Like I'm sure they'll keep getting slightly marginally better. But like, I think the big change has already happened. So we're I don't see us getting another 4% right. Like if you just start running some of the math on that to like what that would mean for performance. Like it's like it's kind of the same idea when we say like 11% benefit. I'm like, look at what that does for your performance time. Like those are just crazy numbers. So yeah, I think some of it's got to be self-limiting. It's got like a motor in the shoe you know. Yeah. Yeah. The other thing I want to ask you about was just the pacing stuff. because it seems like with a lot of these products, the faster you're going the better the product is going to perform relative to the control. because I was thinking about that, I was like, well, there's, you know, there's obviously these guys running the four minute pace in the marathon. And then, you know, for me, like, if I go 100 miles on a pair of super shoes, maybe in the mid 60s if things go really, really well. So, is there a consideration for me there versus someone training like one of these elite marathoners training for a low two hour race finish? I think less for you and more for all the other people running ultramarathons that aren't running right, because when they start getting into the ten minute. So like this, this is the second study that we published. It was like I said, kind of like my interests are always kind of driven by my own running questions, but also like the consumer driven questions. Right. So like, is there a difference across brands and models like we did that paper. Right. And then the follow up to that, was the benefit of these super similar for a three hour marathon or a four hour marathon because most of the research that had been done. In the first few years of like the super, super research was all at like seven minute pace and faster, a lot of it six minute pacing faster. So like people running marathons 330 plus, like, you know, how much benefit was the shoe? So that's what we did. That study was looking at just the vaporfly. That's kind of the most commonly studied shoe. We looked at that at eight minute mile pace and like 930 pace, I think corresponding to like three and a half to like 415 marathoners. and whereas like in some of the previous studies like in our lab, we show like around 3% in the vaporfly, like depending on what study you look at like maybe they call it the 4%. Right. But like it's across the research literature, maybe 2.7 to 4%. but when we did that, those much slower paces, like it was more like 1%, 1.5%. so I think there is, at least for, you know, that shoe and I think it probably carries over to some others, like compared to standard control shoes like maybe reduced benefit at slower speeds. Now, could a company like make a shoe that would be better at the slower speeds versus the faster? I think they probably could. Right. Most probably were trying to innovate for the fastest. Yeah. I think some brands would tell you now, like they probably try to think about the slower and the, the bigger end of their market. Right. So I think what's funny though is that Jeff, Jeff, Jeff was co-author on that paper with me and, and one of the reviewers like we had listed, you know, potential implications for that study. Right. Like at the slower pace is a reduced benefit. And we left off a part about ultra running or trail running. And one of the reviewers called us out and said, I'm surprised, based on the authors, that Jo didn't mention this. Like knowing I don't I don't run ultras or trail, but you know, referencing Jeff and my comment back to the reviewer was like, Jeff was too fast to make those considerations, and I'm too smart to run those distances. so, I think, you know, if you're running ultras at 6:30 p.m., you're probably in the ballpark of all the things that we've tested already. Sure. But yeah, I think the, the, my main takeaway from that study is like, you know, if you're running a four hour marathon, You shouldn't have as big of, like, this blanket assumption that you're going to get a 4% benefit from this shoe. it's like you absolutely have to be in this shoe, right? Like, if you don't like it. Yeah. then don't just assume like you're getting that benefit. And there were more people that the interesting thing and like a lot of the super research is like a good shoe pretty much by and large compared to a control shoe, a traditional shoe. And these studies that faster paces, like everyone gets some benefit like, so when we say like a non responder or someone has a negative response, like getting a running worse economically in that shoe, like very few of any of that across like several super studies at faster speeds and the slower studies that we've done, a larger percentage of like the opposite responders. Right. Like not only a smaller like mean benefit group mean benefit, but like some people who are doing worse in that shoe. Right. So that's I think that's kind of my takeaway is like if you're on a truly slower pace, it's all relative. Right? But for those kinds of places, don't just have a blanket assumption that she's going to be beneficial. Like comfort. Comfort matters. I think the most comfortable shoe is not always your most economical shoe, but I'm willing to bet that an uncomfortable shoe is not economical. Yeah. So it's like just because like on average in these past studies, a shoe out of 3 or 4% benefits where you're running at much slower paces and you don't really feel like it's that comfortable. Like that's not assuming anything about that shoe for you, right? Yeah. So yeah, I think, Across the range of speeds that we kind of looked at in that ballpark. That's kind of my take. That's kind of what I was thinking about with the Wave Rebellion, because I was like, what if I'm like just ripping in that shoe when I'm out training and it's like head and shoulders above everything else? I test, just theoretically. But that shoe, the way it's constructed, is likely not going to feel great for 12 hours or 11 hours. Maybe not. Maybe I'm wrong about that. I've worn it a couple times so I know how it feels in a workout, but I don't know. I haven't taken on a long run yet to see if it kind of loses its desirability as you get longer in it. But yeah, I think that goes back to what we talked about earlier, like in terms of specificity and like taking the shoe, the distance you need to take it or like you got to run a hundred miles to figure it out, or at least at least like, I mean, you're not doing that in training grounds, right? But like how you would have made it, made assessments about other shoes in the past like. Yeah. Yeah. I think I probably get enough cumulative fatigue with some back to back long runs. If I wore that shoe for the entirety of it, I could probably figure out if it was something that I was going to hate. Well I could also change out of it too. Like, that's not the end of the world. If you, you know, maybe I go through 100 K and then switch into something different. Yeah. What's the, what's the alter where it starts trail and then it goes to the roads. oh. JFK. JFK. Yeah, yeah, yeah, I saw, Oh. It was a former triathlete, dude. Is it him, Eli? Oh, yeah. Yeah, he's an ultra now. And his shoe changed on that. Because that's what he was wearing. Trail shoes. And then switched to, like, a road shoe. Yeah. And everyone was like, so impressed by him. I did a triathlon, in my grad school days, and everyone's so impressed by his shoe change. I was like, oh, man, that's standard practice. Like there. Yeah, he had no problem with that. He didn't even have to warm up. Probably with it. All the trainers had to take out their chairs, unfolded, sit down, and take five minutes to get the shoes. Yeah, that is an interesting course though, because you probably don't want a super shoe over the Appalachian Trail. Some guys have done that. I think Jeff did. I think he said he made that mistake. He said he thought he could maybe get through it, save himself a minute to check. But yeah, I think he decided it was a mistake, though. Yeah. Yeah. I mean, being on that course a few times, I wouldn't want to wear that over the Appalachian Trail. I'm not the best. I'm sure there's guys and gals who could probably do it and maybe not lose, but I just I think if you got, like a good set of laces wear and just a crew that had it all set up and ready for you, if you're in and out of that shoe in 30s, you're going to be better off getting something that's going to be a little more specific. Yeah. If you got speed laces on there, not even that. Yeah. So we're so on this topic. We're doing a trail study. I was just going to ask you that. Yeah. We should get you out there for it. Yeah. let's just see if we have your size in our lineup. I got a wide range of sizes, so. So, you know, in terms of, like, questions asked, we did the slower speed pace. We did a spike study, to see, like, what the benefit of this tech and spikes was. And then you started seeing this tech and trail shoes now, right? Yeah. So it's like, well, how beneficial is on the trails you're running at slower paces, different terrain. So we're comparing right now, just like a control trail shoe to the, to Nike's Ultra Fly. Okay, you might have opinions on better Super Trail shoes, but we just needed a starting point, right? Like just it's got foam. It's got Max in there. Yeah. So, not so much to identify. Like the best trail shoe, just to, like, quantify the magnitude of the benefit in a trail shoe. so we're doing Saint Ed's actually managing, like, wildlife preserve here in Austin, while basin. And so there's trails out there, and we got a grant out there to, like, purchase the shoes and do the trail study. So we got, we got like a portable metabolic analyzer. Yeah. And so we're having people run like, self-selected, like 50 K race pace on the trails for multiple reps, like alternating shoes. And then we bring them back in the lab on like the hard, stiff treadmill and test them at the same paces. and are looking at like percent benefit from the shoes. So we've got like eight people done. We're probably shooting for like 16 on that study. So anyone in the Austin area who likes running trails? Yeah, I'll come out there, check us out, knock some miles out in there. Yeah. So the interesting thing on that one is like, you know, we're kind of trying to keep external validity of, like how that shoe's actually used, right? It's like, we could go test you in the lab on a CIF treadmill and the ultra fly at a six minute mile pace. But if people aren't going run their races at that, right, like, so we're that's kind of like self-selected trail race pace, kind of how we did that. So if we go off of what we saw in previous studies at slower speeds or reduced benefit, I would expect maybe a smaller magnitude to benefit from the speed alone, whether that's because of less forces going into the foam or less forces to flex the plate. Like we don't necessarily know that entirely, but, but then you also got the portion of the trail just softer terrain, more undulating turns, that sort of thing. So yeah, we'll see if we see a difference between, like, the stiff treadmill and that, even though the speed is matched. Do they? Has anyone done any testing on treadmills on an incline to see what the efficiency is like when you're up on, like, a pretty steep pitch? Yeah. Yeah, that's a good question. There. There is. There's one published paper, I think actually just a new one I just saw. but, I think it's whiting or whiting. they did. They looked at the vaporfly uphill, downhill, and flat and slightly reduced benefit uphill. So like if 4% on the flat maybe like to a high 2% on the uphill and then the downhill is a lot noisier just because like downhill running technique across people varies a lot. and so, so yeah, but the main takeaway was still certainly a benefit. And they were kind of mimicking the hills of Boston I think. Okay. It's a little baby. It's all relative I guess. yeah. So, slightly reduced benefit. Yeah. And actually, if I can find it, I can look it up after, and send it to you if I can find it. I, I want to say I just saw a recent paper that did some treadmill stuff. It might have been steeper because it might have been more trail focused. So I'll see what. I'll see what that one showed. Yeah. but yeah, I don't. I don't know if it's, if it's, you know, pace related if it's, how you flex that plate, the foam, like, really, there's not a good biomechanical explanation of, like, how the shoes work. And generally, everyone knows the foam is more compliant and resilient. And so there's more energy returned from the foam. But like the amount of energy that if you quantify that it doesn't explain the whole body energy savings, like it's only a small fraction of that. Yeah. so biomechanics haven't really come to some unifying theory on exactly how the shoes work on you as a human. Like, if we did, we could like, predict better, like what shoe was gonna be best for what mechanics and stuff. And like, we don't, we're not that far along. There's one paper that showed, we know, we know it reduces work at the MTP joint. Like the big toe. and the ankle may be too, And I saw another paper recently that said that EMG muscle activity of the plantar flexors or calves is reduced. So I like less work on the cast. So I think that's mostly where it's occurring. but yeah, there's not like a big unifying theory on exactly how the mechanics are helping. Are those forces getting sent anywhere else to any degree, like if someone, starts wearing for the first time, is there any data that would suggest, like, oh yeah, give yourself a little bit of time for your quads to adjust to the variance that you're going to get in that shoe versus a normal shoe or anything like that. Yeah I don't. So you hear about this and the savings like the lower leg savings. But I always wonder about that. Like if there's some sort of, like, forced redistribution that someone. Right. Well, yeah, because this is getting more into the mechanism. But typically you think like if you change mechanics, if you like, reduce forces at the ankle, you might increase the force at the knee or something. Right. I don't know that overall like ground reaction forces are different. between the conditions. so I don't I don't know if you have a big redistribution. Most likely if there's a reduction in work, at least it's probably at the, the ankle big toe reduces calf activity and stuff. But yeah, it might be free lunch. Yeah. Yeah. At least for me personally when I'm writing it is not less research that is more just personal. I feel like when I'm running in I'm like, I think I try to think more of, like going to my ankle, like getting the free work from the. Yeah, the lower leg as opposed to like driving my hip so hard or something. Yeah. getting that like extra spring from the lower leg. Yeah, I definitely noticed that. I mean, I guess I've been in some of the premium foams now for about a month. And what I noticed in the Puma Nitro Elite, I think three Pro three and then the Mizuno Neo Zen. So that's their non plated one. They've got their premium. I think it's their premium foam in that one. My gait cycle felt super smooth. Just like it felt okay. Like things are just like there's no fighting going on here. You're just kind of real fluid through it. Yeah, that was pretty noticeable to me with those two brands, I mean, or models. I've got a lot of other shoes to try yet to see if that replicates across most of that technology or if it is just those two models that happen to be fitting my gait cycle really well. Yeah, yeah. I think when you think of, like the ride of the shoe. Yeah. Like people talk about the kind of sensation felt. Right. Like I think some of that probably has to do with the rocker, different rocker shapes and like, and that's again, that's like less of my research hat and more just like the feel of things. Right? Sure. I do think there's probably, like, when I test people in the lab, I'm like. There's shoes that, like, more people just get along with and other shoes that are a little wonky that less people get along with. Like like, I think the original Alpha fly is a shoe that on average tested highest and like group means. But that one is the one shoe that I think I'm a little more confident saying there's higher and lower responders like all of the other shoes that we tested in that original lineup. I feel less confident saying like, oh, there's higher and lower responders in the vaporfly or like in the meta speed sky or, because, just like there was probably more within the normal range of variability you'd expect like, but that original AB fly a lot of people like, loved it or didn't like it that much and like favorite of like a lot of people get along with I think that Asics meta speed Sky or that whole line up, like just the right of that, probably a little more universal. So I feel like I do see some things like that that pan out a little bit in the data, but also like anecdotal. Yeah. The other thing I found interesting, this might be a Jeff question, but I'll ask you anyway, is just I had Rory Linklater on the podcast last year, and he was telling me that he runs for Puma and he said they had their whole team come out. I think Boston is their headquarters, and they just tested them in like, their, faster and then their, deviate. And something kind of was there was a trend at first at least, where like some of like the men were starting to get, were getting better efficiency gains from the faster and the women were from the deviate, and they thought it was because the weight difference between the men and the women were that like that way that faster was constructed. If you could put a force into it, it really worked much better. But if you were a little lighter and were putting less force into it, the plate may have actually somewhat gotten in the way of the actual progress. So they wanted that non plated because it deviated originally. I mean maybe I can't remember if there's a non plated deviate, but at the time it was a non plated shoe. So okay you saw like I think you know at the trials you saw I think Fiona O'Keefe was wearing the deviate. And I think even Molly Seidel was wearing that one for a while too. And, but it seemed to be kind of like that was the distribution like the heavier male runners. And that's a whole other element, like not just the amount of foam, but like the stiffness of the plate can vary quite a bit like, say, its carbon plated shoe. But the amount of longitudinal bending stiffness can vary quite a bit, like how thick that plate is or stiff that plate is. and that's kind of my take on like my further inquiry on like the slower paced stuff, reduced benefit kind of fits into that window. We had men and women in that study, and most of them were pretty lightweight also, and ran at a pretty high cadence, which would normally translate to like less forces as opposed to like big loping. Yeah, slow cadence. And so. I didn't have a force measuring treadmill in that study when we did that. but that was one thought would be like potentially reduced forces. I was just in the vaporfly, but I've got data that I need to actually finish analyzing. So one of my colleagues over here at UT Austin, Owen Beck, he's a biomechanist. His lab, he's got, you know, motion capture, force measuring treadmill. We brought in a heavy group of runners who were, like, £180 plus guys, your hybrid athlete. Yeah. and then, and then a lighter group, like, was under £140, and we tested them at slow and fast speeds and are trying to, like, parse out if, if it's a speed effect or a force effect of, like the reduced benefits I saw previously. and actually, I just got we that study has been on pause for a while, and, I just got the ground reaction force data from them for that. So I need to incorporate that into our metabolic data economy data. We have to see if anything jumps out. but that I mean, it's interesting you say that about the Puma lab because that's kind of like the same train of thought. Yeah. so we were kind of going down. Yeah, it's interesting stuff. It just adds another layer of complexity. It's like the shoes, the huge or maybe not huge, but big enough variable that you got to think of it the same way, like you maybe we're thinking about fueling in the past or currently too, I guess. But finding the right shoe is a good, good investment. Yeah, yeah, yeah. It's not. You gotta have the right place to do it. But like, if you're in a location, like to do it, it's not. I mean, any athlete who's ever paid for a month of coaching or paid for a physiological or just buy a pair of shoes. Yeah. The prices these things are at. Yeah. Yeah. Then it's not it's not that crazy to think, oh, I'm going to seek out a lab. The tougher thing I have is an actual phone that can email me if they want. I've got, like, a protocol, that if they were like, you know, not local and wanted to, like, go to a lab somewhere, like. Sure. because a lot of university physiology labs would know how to, to do, like, aerobic testing with a metabolic cart but might not like, do running economy testing protocols or protocols. So I've got a stock document I can share with you if you want it. that's like here, this is how you conduct a testing or even even so much as like this is what to ask if you're reaching out to the lab now, the prices might vary, right? Like if you're looking at that's the thing I was curious about too, is because like these labs now, I mean, essentially they're they're mostly probably just doing your typical metabolic cart testing where someone wants to get their like, you know, their energy ratios of fats and carbohydrates, their crossover points and stuff like that, and dial in their training zones and whatnot. Now it's like there's a whole nother service they could offer. Right, right. With shoes. Yeah. Yeah, definitely. Anybody who's got a good metabolic heart who can do VO2 max testing or or, you know, the Substrate utilization concepts you're talking about. They could do this. Yeah. For sure. it is the tech with like, like stride pods or anything useful for teasing out any of them. That's a good question. I've talked to them. I've actually talked to those guys recently. and I'm really interested. Like that's like a million dollar question. If you could, like, create an app. Right. Someone goes around in these different shoes like you're testing. You don't have a metabolic cart, but like, you've got your stride pads on and, like, you take those inputs and then it says, oh, this is more economical. And I know they're hopeful that like, you know, and I think they've got some ideas and leads on it. But I've seen enough. I have enough data. I mean, like on a shoe, like the alpha fly. I've got like probably 50 subjects across multiple studies. And like when I have our, like, data science guy dig into that. Like, we can't even make any real conclusive things. Like the person who runs this way is going to get this matic to benefit. Right. Yeah. Like and that's a lot of data compared to what most people would have on any particular shoe. And so I'm not. I'm not confident like a few isolated people would be like, oh look your, your power was higher here versus here. Like let's make this conclusion like, I, I think I'm hopeful we could maybe come to some conclusion like that at some point, but, so yeah, actually, they, they, they've been really cool. I've, I've, got a couple of, like, the new duo pods that have been playing around with and our next, our next project in the lab with shoe stuff. I'm going to add that I've used them before, but they have a few new features like the latest thing. So, but I think the issue with trying to correlate mechanics to economic benefit is you need bigger data sets, like when we just want to take, Like economic comparisons between this shoe and this shoe. The effect sizes are pretty large, and so you don't need a ton of subjects in these studies, like 8 to 12 subjects in these studies with these large effect sizes, so you can make confident statistical conclusions. But those studies are designed to do that. Like to make comparisons between shoe shoes and repeated measures like the same people testing both shoes. you can get away with a small group for that. But like when you start correlating stuff to those benefits, like you just need more data. You can't have these like small sample size data. The studies have to be designed for that. So like as we aggregate more and more like, especially if you have the same control shoe and like a comparison shoe like I think. But whatever relationships we might find like in the Alpha Phi for that might not be the same relationship you find for the Waverider, you know, like whatever other shoe. So I think it's tricky. The few trends I see, like in the shoes that, the good shoes in the lab, people tend to like mechanically things that change. People tend to have a little bit longer stride length. So it's at a fixed speed, a slower cadence, actually. Right. and with that like longer stride length, like a little more vertical oscillation. Yeah. I see that, but, I don't think we're at the point where we can just say like, okay, you went out and ran in three shoes, and the shoes with the most vertical oscillation were the better shoe, because that's like, I could get to misleading at some point, right? but yeah. So I think I'm hopeful, but I think it's gonna be a while. Yeah, yeah. It'll be interesting to see where all that goes. Well, just tech in general is gonna accelerate over the years, and who knows what we'll have available in five years that we're not even thinking about now, but. Right. Well, and surely we'll have stuff we can measure, but like, just because we can measure it. Yeah. Should we do anything with it? Right. Like, yeah. I had Steve Magnusson and asked him about that. And he was like, yeah. Every time we try to measure something, it just ends up becoming the end all, be all, and it just sends us backwards. Yeah. Just because we can measure something doesn't mean it means something. Right? And it's like, that is like the age of wearable tech. That's like a big, big thing, I think. Yeah. Yeah. Yeah. The weight one I thought was interesting too, because I think we do see a lot of variants there across populations in terms of. Like what? Like who's wearing these shoes because like when they first came out with these shoes, I wonder if Nike, maybe they've said something about their initial thoughts of what they were going to do with that product. But it seemed like for maybe a day, there was a question of like, is the running world as a whole gonna gravitate to these? Or are they just going to be like that? Like this is sacrilegious. Get rid of it. And it was like immediately everyone was in them. Oh they're everywhere. Yeah, I like, like the accounts that like, share funny people. Places, places people wearing. Yeah. Just wearing them around. Yeah. Like doing squats. Yeah. You know, chick fil A line or something, you know. Yeah, yeah. They've hit the casual market too. Yeah. So. Well mall walkers. Well it's like, I don't know, like some people do, like, when people ask like, how much should you be wearing these shoes? Like, you know what, like, most of us are not elite athletes. And if you enjoy running in the shoes, then you're running the shoe. Like, man, it's fun to run faster. It's fun to, like, fill that spring and cushion and, like, so, yeah. why not? You know, it's like a new toy. Especially when the new. I mean, like, the foam. I think you will. I mean, you're already seeing the foam in way more training shoes, like. Because. Yeah. Which makes me cringe because it's like, now I gotta buy $200 training shoes, right? Because I'm like, man, I just love the. Yeah. Like, I just enjoy the shoe more, you know? yes, I, I think you'll start seeing that foam in more and more places. Probably. Yeah. Yeah. I think you're, you're seeing a lot of brands that have their, their foam figured out are starting to distribute it into more and more models. Yeah. And that was you kind of mentioned that before. But I was like because now you're actually seeing like brands say like, okay, here is where this for the five K, this for the tank, this for that. And that's mostly bogus I guess. Well I mean, I think the shoe company is probably always going to want you to think you need for shoes. Yeah, yeah. Because you don't have to buy just one then. But Yeah. You got three performance shoes then. That's all one category. Really? Yeah. From my perspective, from when it comes to like a racing shoe. Like I said, like your most economical shoe, if you can wear it for the longest distance and that's the same shoe like. Yeah. Like for me, I'm. That is my most economical shoe. I'm gonna run in the marathon. I'm gonna run it a mile, like, So, so yeah, I'm not convinced. And I've tested like that, like a streak fly or something like that. And it's not, it's not better for me. So, not in the lab. I feel so, Yeah. I mean, when people ask me about getting shoes, I usually tell them, like, you'll probably. I mean, if you can make the initial purchase, you'll probably save money if you buy something like a three shoe rotation, but you probably don't want A5K race or a half marathon race or a marathon racer. You probably want one racer. Then, like we were talking about before, a lower profile firm shoe that you can use in the gym and you can use to kind of strengthen your feet and things like that. And then maybe just like a workhorse that you're going to be able to get close to six. Yeah. Yeah. I'm not necessarily against having multiple shoes for that. In fact the one study that when it comes to running shoes and like injury risk that amounts to anything because like really running shoe market is not solved. Injuries right in any which direction. Right. Not minimalist or maximalist. And the one study that, like people will cite or reference is a study that looked at. Injury risk was less in runners who rotated more shoes. Yeah. and for whatever reason, that is, if just the shoes are rebounding in between or probably more than anything, I think even more of like you're varying, you're exposing how these tissues are being loaded repeatedly. Right. Like is the same reason like getting on the trails every now and then. just just varying how those tissues were being repeatedly loaded. So yeah, having a couple different trainers or a racer mixed in there like that makes more sense. Yeah. To me then, like, I have a really hard time thinking that someone has an ideal shoe for a half marathon. That's different from a marathon. Right. Yeah. People talking about that, they're like, oh, that's not this is not good enough for me for a half, though. Like, wow, wow. What it's like what what what how many seconds per mile difference you're talking about here. Like. And all of a sudden it's when we flip the script, I just don't think we're that sensitive. Yeah. One thing I did want to ask you about, like, you know, because we throw around all these numbers about efficiency and those are coming off of something. So initially like there was like a control shoe that it seemed like all this research was being based off of. How does that change over the years? Because, like, I mean, the way I think about it is like in a perfect world, we'd use a control shoe from like. A time prior to super shoe

. So we can always see the continual growth. But I would imagine as shoe tech improves, the control shoe becomes something that's a little better than the old shoe was. Old shoes you're making. Yeah. I mean, this is definitely one of the challenges of academic research and like having some consistency across these comparisons is there's really never been a standard control shoe. And some of the first couple studies they use the streak, the Nike streak that was like the marathon champ at the time. Right. but at some point those shoes are not available anymore. I've got a couple really old ones in the lab that a buddy gave me. It was like 500 mile ones just for the sake of having them. but yeah, like, at some point you can't even get that shoe anymore. So like, in my lab, you know, three years back when we started this, I started using the Asics HyperSpeed, which was the Ryan Hall special. That's the half marathon record that Connor just finally broke. Right. That was Ryan Hall's shoe. They like to restart the iterations of it. But that was the hyperspeed. and I've got this like funny quote from like an old let's run article from like however many years ago of like Ryan Hall praising that shoe, saying it's the best shoe ever. Like it's just I love it. and it's like so incredible. Like what he did in that shoe, right? Yeah. so that's I've held on to that shoe as my control shoe. So, like, I have a standard control shoe in my lab that I refer to, but that's not the case across every lab. and never, never will be. Really. Just because you can't, you can't. There's not the one shoe. This is this is, Roger Caron, great researcher about making a set of t boulder. He's retired now, but he was. His lab is where that 4% study was when he first did it. he suggested to me a while back, you should start using the, Nike. What did he tell Cortez? I think, okay. As, like your standard control, because it's never changed. Yeah, yeah. And so it's like, it's like the marathon shoe of the 60s, 70s or whatever. It's never changed. And it's like. But that shoe even is like, it'll be, like, hard to get at times. Like it'll be like, limited release and like it gets bought up for casual wear and like, so, so yeah, I don't, I don't know, there's a perfect solution. I like kind of like internally what we've done is like, at least in my lab I've got a standard, and then I like whenever I bring people in for like case study testing. I mean, at the end of the day, you really just want to know, like, what racing shoe is best for you. So you could just test racing shoes in the lineup. I like having a control shoe in the lineup because it gives me more confidence in our conclusions. When I can say, okay, all of these shoes are within 1% of each other, but you were 4% better than the control shoe. Like if everything was within 1% of each other, I'm like, okay, how's our day to day? Like, yeah, you know, is are you just a non responder. Yeah. so I like having something that's worse that like we're confident is going to be worse. Sure. But it's not necessarily required. But then for me the other reason I do it is like I've tested, probably you can look back at old, old like Instagram stuff in my lab rundown account, like there's a slide I've got where I tested like a couple dozen shoes over like a year period. And I always had the same control shoe on the fly in the lineup. So it's kind of like a transitive property comparison, like, like, you can, like, rank it relative to what those two shoes were on any given day and kind of normalize it to that. Yeah. which is, which I think actually probably worked pretty good. and so it's been nice having a standard controller for that, but yeah. Yeah. It's not across the research lit. That's not the case. My first thought was like, Nike should just bite the bullet and just have a big stash of control shoes that can be distributed to anyone who wants to get in on the research. Then I was thinking about that. I was like, I wonder how much of a difference would it matter? Like if somebody, let's say we go back in time and people weren't all wearing the same racing flat, they were going with whatever brand they found most preferable. Would it matter if someone was like, let's say like the Nike Cortez was that control shoe, but then not the person who's testing would have never picked that shoe when it was, they would have picked a different shoe. So does the control shoe need to match the person? I guess that is what I'm asking. I mean, so like if I have people come in for a case study test, usually they'll bring in something like a flat, which hardly exists anymore. Yeah. But or like a lightweight trainer, like, like a tempo shoe that maybe, like, maybe has a phone but not the plate or something like that. It really I just think of it as like an internal mechanism to be like, okay, here's something we're confident might be worse to, like give us some sort of comparison. But I mean, at the end of the day, the real thing is like, how do race shoes compare to each other? Yeah. so I don't I don't know that it's that critical. Oh, sure. it's just like a nice kind of point of comparison. But yeah, I think when I have people come in like that, I usually use something that they're familiar with, not some global standard that they might not have ever considered. Right. But yeah, but even then, I guess it's not like they're raising the marathon in it, so they don't need it to be tolerable to the degree they would if they were doing a race. Yeah. I mean, the other benefit of bringing something in that's in your own lineup is like if. You're doing some hard stuff, but you're not like putting on your ratio. This is like a shoe. You might mix in there and do instead. Like, if you know that, oh, you're 4% better in this race shoe versus that shoe. Like, you kind of like to give yourself some slack when you're doing tempo intervals or something like that, okay, I expect maybe a little bit slower in this, right? Like not the same pace as or. Yeah. like make some workout adjustments, maybe based on something that you actually have in your lineup. Yeah, yeah. Well, you know what? When I come in and test with you, I'm going to bring. I actually have the shoe. I ran 1119 and that is the American record for 100 miles. I mean it's got 104 miles on it, but it's in good enough shape. Oh, yeah. That's not too much I'm gonna test. That's just the one I'm gonna use. I want to test that one and see the percentage difference between that one and some of the other shoes, and then start running math and see how fast I would have been. Yeah. So that's so that's the math is actually so, so I thought we were going this direction earlier. So as you say, we're measuring this in a lab. You get oh yeah. Let's say you get a 4% economic benefit. Does that translate to like a 4% velocity or time improvement. And it's not quite like a one for one relationship because as you run faster and faster, like, energy cost kind of scales up a little bit. Non-linearly, an increase in wind resistance is part of that. so some folks have done the modeling for that. And I think the general rule of thumb is like about two thirds of the benefit. So of the economy benefit in the lab, you get about two thirds of that in velocity or time improvement. So if you're the easy math would be say like a 3% economy benefit would translate to a 2% performance time. Okay. so yeah, but we could definitely do that math. Like people in the old Ryan Hall should have done the math on his shoe. Yeah, okay. Let's say he was in, like a speed ski or alpha fly, like. Yeah. What's he running at? Half 59? Whatever. Down to like I'm pretty confident. 5830. Yeah man. So but without having the percent value like. Yeah. Yeah. Yeah. That is, it's interesting that the different surfaces too are like how big of a difference it is when you're testing on the treadmill versus on the roads. Because most people are going to be running like a road marathon or something like that. Yeah, yeah. So the one thing that people kind of emphasize in lab testing is to have a stiff treadmill. okay. So if you're on a treadmill that, like, flexes a lot, then like that's creating its own element of cushioning and compliance that like, maybe he's like shadowing with the shoes doing. Yeah. So some folks have made arguments like, well, there are some studies even showing they are independent of shoes. That economy is better on those softer treadmills that help kind of cushion your landing a bit. there's a point where that would not be the case to, like, imagine running on sand or something, right? Yeah. You could get compliant. But, and then how they just kind of bounce back. Weird. Some of them are like the gym treadmills. It's like a springboard. Yeah. so, so, so you don't want that on your lab treadmill? like, we were my original study. We did. We had a really firm treadmill deck, but the belt was one of those cushioned rubber ways. So even like, the biomechanics purists would be like, oh, that's too compliant with that Woodway deck. but, yeah, my treadmill in the lab, I just shim the deck, I shim the frame so the frame can't flex. Okay. And then like, there's little bumpers that the deck railings sit on, and then they replaced them with rubber to like aluminum so that they don't bounce as much or cushion as much. But that's what I'm doing a lot. I think if you, if you, if you prevented the frame from flexing, that's a bigger thing. But so most people would say if you got a stiff treadmill it probably translates to the roads. We actually that's that the first study I did here in Austin actually was a couple summers ago. This is why academic research never answers all of our questions really rapidly. Right. Because it takes the better part of a year to study. And then that paper might be in review for six months. And like, finally it's published. Right. So like that's in the final stages of review right now. But we compared the running economy benefit of a super shoe in the lab on a stiff treadmill to the roads. And so we did like motor pacing with a scooter okay. Like cruise control. Cruise control setting on a scooter. Yeah. On the roads. with a portable metabolic device and pretty much the same benefit, same run economy benefit. Okay. Versus tricycle. So I think if you have a stiff treadmill, results probably translate pretty well to the roads. Is that portable tech getting pretty good now that you can. It's getting better and the price point is getting better. But at the same time, like we're talking about with the boom of wearable tech, there's also devices that are coming out that I'm probably super skeptical of. Like so we the kind of gold standard in research has been cosmic K4. It's probably a 3045. Don't quote me on the price, but tens of thousands of dollars. This device. Oh, okay. the little backpack, one that you might see some people doing and those things that the price point and that's like, pretty much exclusive to research labs running R&D kind of stuff. Right. But the V2 master that you probably see is like a little blue mask with the white piece on it. Yeah. that you've probably seen more people in like, social, fitness testing stuff using. Yeah. That thing's like six grand. It's a way better price point compared to the 40 grand ones. It just has a VO2 sensor. Doesn't have a CO2 sensor, so it's not. You can't technically get caloric expenditure. Truly, you get oxygen consumption. You can make some assumptions, but. But it's pretty good. the reliability testing I've done on it, like, it's not as good as, like, my big lab grade cart. but it's not it's not bad. Like, we were able to basically prove the concept was like we were able to the same three, 4% benefit we saw in my study back, like on our lab grade metabolic cart with the alpha fly we saw with this portable device both on the treadmill and the road. So we were able to discern the same group mean differences. Sure. Which gives me enough confidence, at least at the group level, to, like, say, this device works pretty good. I have more confidence giving advice to elite athletes if we're using our lab grade card. Right. Or or if I'm using that, that cart, that little mobile device that's more noisy. Like I want to do more repetitions or more trials to make sure we cut down on some of that noise. especially when giving someone like you recommendations. But like with our lab grade one, it's a little easier to do that. So. Yeah. So, yeah, works pretty good. the one issue with that, that portable one we've had is, At faster paces. it'll, like, deflate some of the readings because, like, the air flow into it, like in the reverse direction. Like if you were to go cycle in it, like it would, like, deflate. The reading's bad. Yeah. But, like, when we've been using it on the trails, like the, the values make sense for, like, the paces compared to the treadmill. But when people were running really fast on the roads with it, like it deflated those values. So but it's still there's still percent differences. We're we're similar. So okay. So yeah I think that's what you. Yeah that's and that's the same device. If you see like the the Norwegian group with triathletes, the Olav. Oh. Who who was names escaping me right now, the Leech elite, Blumenfeld and, Gustav Eden. Yeah. Their coach who's on everything? huh, they're they're, like, partnered with that company for that. Okay. Yeah, they're using it. So I think I think it takes a little bit more like, kind of like adapting to what the numbers are giving you and like, but I think, I do think there are some devices like that that are like making a little more feasible. but at the same time I've seen there's some other one out right now that's like the thing doesn't even like cover your whole mouth, okay. Like just like sits right here. Yeah. Like, how is that going to get any kind of reading and, and that's like a $600 device. People have messaged me on Instagram about it. They're like, hey, do you think this thing would work? I'm like, I don't know. Yeah, I wonder if they have any sort of have they? You'd think they would. Maybe they don't want to, but like they would test it alongside some of the setup that you have. Yeah there is and there is some, some studies like that actually there's just a recent paper that was giving more credence to that V2 master, especially against like the, the other mobile, the high high end mobile cart that's out there. so there are some papers like that, but, I think it takes it's kind of like one of those things we're talking about, though, like if you're using any kind of tech, just blindly accepting the numbers it gives you versus like running some of your own reliability statistics on it and then like using that to make interpretations on like kind of magnitudes of differences between interventions. You can't just kind of blindly go at it like it takes a little bit more skill. I think that's where being a good sports scientist, right, is not just like handing you exactly back with the software said, like, blindly. Right? Right. Yeah. Some interpretation that still needs to be done, right? yeah. Cool. Yeah. Are we missing anything? What are we missing? You talked about your 100 mile shoes earlier. So another. Another thing that always comes up is like, how long do these shoes last? Oh, yeah. Yeah, yeah. and I, I've heard I've heard both ends of the spectrum. Like, people will be like. Oh, no. So you saw the marketing originally behind like, the $500 shoe, which they kind of backtracked, I think. Yeah. Yeah. And so, I don't know, maybe it's not just that. Right. I think for example, the zoom foam, at least from what I've tested, is like running the economy at a fresh pair of flies. Now they've also got like the pod element right there, the pod element. So maybe it's not just the foam, the longevity of the foam, but that air pressure pod maybe lasts forever. Yeah, if it's not popped or whatever, but, I had a pair that I tested fresh, a pair that had 250 miles in, like, almost no difference. Oh, okay. For 4.5%. Oh, wow. Benefit compared to my standard control shoe. So with 250 miles on them, I got that pair up to like 5 or 600 miles, and I never retested them, which I should have, because I'm still pretty sure it was likely to beat most of the market for me personally at least. The upper is more worn down than anything other than the whole duct tape. The upper before the. I feel like the shoe totally feels flat, but, so at the price points people would do if they knew it was going to give them the same. Yeah. So I think that the good foams will probably last. Now there's different ways they foam out the foam too that might affect that longevity. But I think for standard stuff like that I think it's pretty good actually. Not bad. and I think Jeff Jeff's got some of the materials testing, like foam deformation, like loading data that would show that for small pairs of his that do pretty good still in terms of compliance, resilience. Now is that because like when I think about a shoe with 250 miles on it, I think of that spaced out over weeks or months of training. What about a hundred miles straight without any break? Does that change that relationship? Well, I think there is some stuff I'd have to go dig for papers, but there is some stuff I think on, like how long it takes for film to rebound and some, like actual imaging studies, like imaging of the foam compression, like how long it takes to return. Right. so whether or not that would show up in lab testing in the economy. Right. Like, like you could look at the materials testing of that, for more of an engineering imaging standpoint. But whether or not that would show up in like the economy, we could we could test you could go, go, go beat the hell out of a pair of shoes for a few hours, and then you almost need, like, someone to like, if we want to keep you as a, like, not a variable in that equation, you need somebody else to go, like, hammer the shoes or get one of those, like, robot machines. Yeah. There you go. Yeah, yeah, there's a guy out in California who does a bunch of the helix in the company. They do a bunch of the testing for the shoe companies, and he's got like a machine that does that. Yeah, just pound it down. Yeah. Because I was always thinking about that. I was wondering, like, you know, maybe I switch a pair at 100 K just. Just to get a fresh pair on. But yeah, sounds like it's either. It sounds like from a longevity standpoint, that wouldn't be necessary to be more of a question of just within that time frame. Yeah, yeah. I think to my point, I was talking more about just accumulated wear on the shoe. Like the shoe has not been hit with a hundred miles right before I test it. but yeah, we could, It's a good question. It's a good application to your stuff. We need to get, like, five people at the same shoe size and just have me around 20 miles, and then I'll get on the treadmill and test it and see. Yeah. Yeah, that'd be interesting. But yeah, that. Yeah, it's. I mean, I guess I could always hedge the bat and change anyway and. Yeah. Yeah, definitely. If you get a quick change in, you can always feel it out to just see what it feels like. Yeah, yeah yeah. That's true. You could have I mean I'll have a second set there anyway just because you better have it and not need it. Yeah. Type of a thing. But yeah I mean with, with some of these controlled hundred milers, I mean I'm usually stopping. I think my fastest I stopped I think maybe 2 to 3 minutes total. It was just bathroom breaks. And then my fastest time prior to that I think was like 60 maybe 90s total. Yeah. So there's not a lot of downtime in there, but I wonder if there'd be a way to just pair it up where it's like, or I'm going to use the bathroom, bring me my shoes. I'm going to try to do two things at once. Yeah. Have you put those quick laces? Those stretch. Yeah. That's probably the move. It's. Yeah. It's seconds. Just quick. Do it. Yeah, yeah. You got me thinking I always like, have the wheels turning. I was like ten studies in my head. Then I can only do one of them. Yeah. Like, but. Or like a case study. You got wheels turning in my head, like, whether or not we could design something to do that. Because of that, a similar note to that, like the question of like, do the shoes benefit you more later in a race like those? It's hard to pull off those studies because you go like, have to have someone come in, run fresh, go run for two hours, test them again. Like it's just way harder to do that than, yeah, bring you in the lab for just an hour and a half. Yeah, I did think of something I was going to ask you there. I saw online someone had something like this. I think it was just like a web page, like a Google Sheets thing where they had like just a bunch of inputs where you could put in like, this is my marathon PR in just a standard pair of running shoes. If I put on super shoes and it was like a translation chart. Yeah, yeah. Do you think that's a pretty way off or. Well, it depends on it. You probably have to see the back end of the equation. Yeah. So there's, there's, there's one I would give you to use it, which is the when I was talking about like the rule of thumb of like 3% economy benefit around 2%. Okay. Velocity improvement that's modeled off of this, this, This paper published by Charlotte Kip, who's a really fast runner, competitive runner herself. with that paper, they have an Excel file that has a calculator. I wonder if that's where I got it, if it was like a complicated looking Excel file and, Yeah, I'll be there. I'll send it to you and see what you think. Yeah, maybe. So if that's if it's that paper, then. Yeah, that's probably the best modeling that's out there. if it's from that, that one from that paper. but you have to know your economy input first, which would come from the lab, and then you put in your paces and. Yeah, that's it. Scales that economy to time benefit based on paces and body surface area and all this okay. But yeah, I like that one. I think it's reasonable. Yeah. Cool. Dustin, where can people find you? so if you want some old, outdated Instagram content lab rat rundown. It's still good stuff. Yeah. Whatever. You know, that's the thing about Instagram, right? Is like the algorithm only benefits stuff that happened in the last 24 hours. Yeah, but like I have never posted a bunch of stuff to that Instagram, so it's not that hard to go back and scroll through and see all of these studies I'm talking about. In all the case study testing I've talked about, like, so yeah, it lives there as kind of like a log for that. It's just like the algorithm is not going to show you my account anymore because I don't do much with it. but, until we go and share it in our stories. Yeah. And then, so then my lab, my lab, I, it's endurance performance lab, which that's its long name, but you can spell that out. You'll find me for my lab on Instagram now. And so that's my lab at Saint Ed's. And one of the things I'm trying to do is expand, like, community based testing services. Right? Like, it gives my students practicum training. It generates a small amount of money to help fund research studies in our lab. And like it's the lowest cost exercise testing people are ever going to do. And it's with physiologists. Yeah. You know, running researchers. So, I think it's a good gig. Good deal. So deal so they can find me. Endurance Performance Lab if they're in the Austin area or come through Austin and want to test right on. the lab websites linked on there. yeah. Cool. And they can know that they're funding some future. Super. Yeah. You know, it's like doing fun projects to like, if you want to pay your salary, which I don't have to do because I'm at a teaching institution like my main job is teaching, right? Like, so, so to do fun research projects, you just need a few thousand dollars here and there. So it's like, yeah, if I can generate some money, we're going to do a cool Martin Bicarb thing this summer. Oh, cool. I've been kicking around kids and running economy things lately. so. Yeah. and then. Yeah, future school purchases stuff. So. Definitely. Right on. Well, Dustin, it's been great to chat. We'll have to have you back in the future when some new. Yeah. You guys in the lab get some video and go over your results there. I'll be curious because I think Braden has pretty different gait cycles. So I think we'll get maybe some differences between the two of us, but cool. That'd be great. Let's see. So awesome. Well, thanks so much for some time. Hey, man. Thanks.