1 00:00:07,480 --> 00:00:10,280 Hello everybody, and welcome to the Doctors Running podcast, 2 00:00:10,280 --> 00:00:12,680 where we, a group of doctors of physical therapy, discuss the 3 00:00:12,680 --> 00:00:15,240 art and science of running and the stuff that we put on our 4 00:00:15,240 --> 00:00:17,520 feet. Today is a really exciting day 5 00:00:17,520 --> 00:00:19,480 for us. On the podcast, we have a guest 6 00:00:19,480 --> 00:00:22,040 that we've been looking forward to talking to for a long time, 7 00:00:22,040 --> 00:00:25,240 and it's probably someone that everyone who's listening to this 8 00:00:25,240 --> 00:00:28,040 podcast has heard of or they've heard of. 9 00:00:28,040 --> 00:00:32,000 The study that has, I would say in some ways has quote made him 10 00:00:32,000 --> 00:00:33,920 famous in the running shoe world. 11 00:00:34,120 --> 00:00:37,600 It is Doctor Walter Hookhamer. We are so glad that he's here. 12 00:00:37,800 --> 00:00:41,200 Doctor Hookhamer is a researcher focusing on bio mechanics and 13 00:00:41,200 --> 00:00:43,840 energetics of human locomotion or running. 14 00:00:44,280 --> 00:00:47,760 He currently leads the UMass integrated motion lab. 15 00:00:48,040 --> 00:00:50,360 And again, if you've been in the running shoe space and are 16 00:00:50,360 --> 00:00:53,000 listening to this podcast, you've likely heard of one of 17 00:00:53,000 --> 00:00:56,240 the most famous studies of his colloquially known as the quote 18 00:00:56,240 --> 00:01:00,440 4% study, which looked at that original Nike Vapor Fly shoe and 19 00:01:00,440 --> 00:01:02,560 produce the results that gave that shoe its name. 20 00:01:02,880 --> 00:01:06,280 Beyond his researcher, he's also a runner and ultra runner 21 00:01:06,760 --> 00:01:09,440 himself and is the founder of the Trail Ultra Mountain 22 00:01:09,440 --> 00:01:11,960 Alliance. So we are so pleased and honored 23 00:01:11,960 --> 00:01:14,880 to have you join this podcast. We cannot wait to hear what you 24 00:01:14,880 --> 00:01:17,520 have to say about kind of some of the newer research that 25 00:01:17,520 --> 00:01:20,080 you've that you've been producing and the things that 26 00:01:20,080 --> 00:01:22,640 you've been thinking about. So thank you so much for 27 00:01:22,640 --> 00:01:23,960 joining. US No, you're welcome. 28 00:01:23,960 --> 00:01:27,000 It's a pleasure to to finally meet you too and heard about 29 00:01:27,000 --> 00:01:30,480 your podcast from people I've worked with and it's a excited 30 00:01:30,560 --> 00:01:34,480 to talk about some of our latest research always anyways, so 31 00:01:35,040 --> 00:01:37,960 let's get into it. Well, before we get started, I 32 00:01:37,960 --> 00:01:41,080 should also say it, Matt Doctor, Matt Klein is also with us, who 33 00:01:41,080 --> 00:01:44,440 recently passed his PhD dissertation defense. 34 00:01:44,440 --> 00:01:48,520 So congratulations, Matt. That's a huge step in your 35 00:01:48,640 --> 00:01:50,640 academic journey and your teaching and all that. 36 00:01:50,640 --> 00:01:53,360 So I'm sure you're sleeping a little bit better now than you 37 00:01:53,360 --> 00:01:55,320 were a couple days ago. Just a little bit. 38 00:01:55,320 --> 00:01:57,880 You can still see the the backs of my eyes, but that that's 39 00:01:58,120 --> 00:02:00,680 yeah, that's normal. Fantastic. 40 00:02:01,280 --> 00:02:04,560 All right, but just to kind of get to know you a little bit 41 00:02:04,560 --> 00:02:08,080 more, Doctor Hookhammer or do you prefer Walter? 42 00:02:08,080 --> 00:02:10,120 How do you want to be referred to on the podcast? 43 00:02:10,120 --> 00:02:13,840 Walter is fine with me, yes. OK, Walter, So what is something 44 00:02:13,840 --> 00:02:17,920 about you that you don't think anyone else really knows about 45 00:02:17,920 --> 00:02:19,760 you that's listening to this podcast right now? 46 00:02:20,000 --> 00:02:23,520 Yeah, I, I, I think obviously I'm a running scientist and I'm 47 00:02:23,520 --> 00:02:27,040 a runner, so I, I went something outside a running atmosphere. 48 00:02:27,040 --> 00:02:30,400 So I think one of the the fun stories I always have is that 49 00:02:30,520 --> 00:02:35,280 when we moved to Massachusetts from Boulder, Co, we we 50 00:02:35,600 --> 00:02:39,280 basically drove across the country with four chickens in 51 00:02:39,280 --> 00:02:43,560 the back of our car. We have pet chickens and we love 52 00:02:43,560 --> 00:02:46,960 them and we were not going to leave them in Colorado and we 53 00:02:46,960 --> 00:02:51,560 were not going to ship them. So we went to trip and we put 54 00:02:51,560 --> 00:02:54,760 them in the back of the car, which was quite the adventure, 55 00:02:55,360 --> 00:02:59,960 but they all made it. Cooper, a cage or just kind? 56 00:02:59,960 --> 00:03:08,040 Of we had, I think 2:00 to 3:00, big duck crates as cages, which 57 00:03:08,040 --> 00:03:12,080 we sort of opened up to each other so that they sort of had 58 00:03:12,160 --> 00:03:15,520 that space to move around, but still with the back of the car. 59 00:03:15,520 --> 00:03:18,160 So not a lot of space. Yeah. 60 00:03:18,240 --> 00:03:21,520 So they weren't necessarily free floating in the in the back of 61 00:03:21,520 --> 00:03:23,680 the car that they could jump to the front seat and and make it 62 00:03:23,680 --> 00:03:26,640 dangerous. So we we did take care of that. 63 00:03:28,640 --> 00:03:30,400 What a journey. That's awesome. 64 00:03:30,560 --> 00:03:32,400 Definitely. I don't think anyone if, if 65 00:03:32,400 --> 00:03:34,840 someone does know that about you, who's listening to this? 66 00:03:34,840 --> 00:03:36,760 Who hasn't like been in your inner circle? 67 00:03:36,760 --> 00:03:38,960 That's a little creepy if anything else. 68 00:03:38,960 --> 00:03:42,000 So great. Well, we are going to transition 69 00:03:42,000 --> 00:03:45,240 to our subjective for the day. And I felt like it was only 70 00:03:45,240 --> 00:03:47,800 fitting to ask everyone the question of what is your 71 00:03:47,800 --> 00:03:50,960 favorite super shoe? Knowing that Walter is somebody 72 00:03:50,960 --> 00:03:53,240 who's been doing a lot of research in the energetics of 73 00:03:53,240 --> 00:03:56,480 footwear. And so I'll pose it to you as 74 00:03:56,480 --> 00:03:59,440 well. Walter, what is your favorite 75 00:03:59,480 --> 00:04:02,560 super shoe that you've either ran in ever or right now? 76 00:04:02,680 --> 00:04:05,120 So I think, well, it's it's the same. 77 00:04:05,120 --> 00:04:09,680 So right now and ever I recently ran the Boston Marathon wasn't 78 00:04:09,680 --> 00:04:13,240 the greatest marathon I ran though in the in the the Puma 79 00:04:13,240 --> 00:04:19,240 deviate Elite 3, which I think is out by now, recently past few 80 00:04:19,240 --> 00:04:22,920 days weeks. But at the time of Boston, 81 00:04:22,920 --> 00:04:25,000 right, it was only released sort of it was released for the 82 00:04:25,000 --> 00:04:29,280 trials for the women qualifying and and some more people ran in 83 00:04:29,280 --> 00:04:32,240 Boston. But yeah, I've been running in 84 00:04:32,240 --> 00:04:37,040 that shoe for the Boston build and Boston and I like a lot. 85 00:04:37,560 --> 00:04:39,000 Fantastic. That's great. 86 00:04:39,600 --> 00:04:42,440 Well, before we get into the topics for today where we're 87 00:04:42,440 --> 00:04:44,560 going to talk about something called the fallacy of single 88 00:04:44,560 --> 00:04:47,600 trials, as well as just diving into some of the previous 89 00:04:47,600 --> 00:04:51,080 literature and now new literature that Walter has been 90 00:04:51,080 --> 00:04:53,680 producing on advanced footwear technology or super shoes. 91 00:04:53,960 --> 00:04:56,800 We do want to remind you all that if you were here last week, 92 00:04:56,800 --> 00:04:59,320 you heard a longer expose on this, but this episode is 93 00:04:59,320 --> 00:05:04,480 sponsored by Scratch Labs and they have been generous in 94 00:05:04,480 --> 00:05:06,880 working with us to get you all as much as possible. 95 00:05:07,080 --> 00:05:09,840 And so they offered us like kickbacks on stuff and we said 96 00:05:10,000 --> 00:05:13,480 no, can we just do things to get people who are listening more 97 00:05:13,880 --> 00:05:16,400 access to things? And so they said, sure, let's 98 00:05:16,400 --> 00:05:18,760 give people 25% off of their first order. 99 00:05:18,760 --> 00:05:21,440 So if you are listening to this and you want to order something 100 00:05:21,440 --> 00:05:25,200 from scratch, you can use the code Dor 24 and that will get 101 00:05:25,200 --> 00:05:28,840 you 25% off your first order with Scratch Labs. 102 00:05:28,840 --> 00:05:33,240 So let's move forward though. Speaking of Scratch Labs, I do 103 00:05:33,240 --> 00:05:36,040 want to ask you, knowing that you run marathons, ultra 104 00:05:36,040 --> 00:05:40,280 running, you've all extensive running history, what sort of 105 00:05:41,840 --> 00:05:44,800 strategies do you use for your nutrition and hydration? 106 00:05:45,040 --> 00:05:47,320 Do you use products or normal kind of food? 107 00:05:47,320 --> 00:05:48,840 Like what? What way do you like to go about 108 00:05:48,840 --> 00:05:51,360 it? Yeah, no, I'm, I'm really sort 109 00:05:51,360 --> 00:05:56,600 of the, the sugar addict here. And so when I run, I started as 110 00:05:56,600 --> 00:05:58,880 marathon runner, right. Well, I didn't start as marathon 111 00:05:58,880 --> 00:06:02,840 running, but when I started doing long distances, started 112 00:06:02,840 --> 00:06:05,920 running the marathon. So you have your, your gels and 113 00:06:05,920 --> 00:06:09,280 goose and, and, and sort of your sports drinks initially 114 00:06:09,280 --> 00:06:12,200 Gatorade, but at some point realize that your own powder 115 00:06:12,200 --> 00:06:16,880 sort of work better. So for ultras, I use modern gels 116 00:06:16,880 --> 00:06:21,880 or science and sports gels and then yeah, just a lot of sugary 117 00:06:21,880 --> 00:06:23,880 water. So that's Tailwind right now for 118 00:06:23,880 --> 00:06:27,320 me. Scratch Lab works as well, but 119 00:06:28,360 --> 00:06:30,600 it's, it's kind of sad like sometimes you run these ultras 120 00:06:30,600 --> 00:06:32,960 and they have these fancy 8 stations with all these snacks 121 00:06:32,960 --> 00:06:35,000 and sometimes they're even vegan too. 122 00:06:35,000 --> 00:06:36,520 And I'm a little excited about it. 123 00:06:36,880 --> 00:06:41,120 And then I just blow by and stick to my sports drinks and 124 00:06:41,120 --> 00:06:44,160 gels. And then after I finish I might 125 00:06:44,160 --> 00:06:47,640 just get going with the vegan cookies or, or or something 126 00:06:47,640 --> 00:06:50,520 else. But when I run particularly sort 127 00:06:50,520 --> 00:06:56,600 of up to 50K ultra trail stuff, yeah, that's what I can get away 128 00:06:56,600 --> 00:06:59,000 with. When I'm running more towards 7 129 00:06:59,000 --> 00:07:01,920 hours, then at some point you you're just gonna stop at the 130 00:07:01,920 --> 00:07:04,600 date station and take your Oreos or something. 131 00:07:05,480 --> 00:07:08,320 But. Whatever sounds digestible. 132 00:07:08,440 --> 00:07:10,040 Exactly. Or swallowable. 133 00:07:10,040 --> 00:07:13,400 Yeah. But but mainly before that up to 134 00:07:13,400 --> 00:07:16,240 that distance sort of scientifically just go with the 135 00:07:16,240 --> 00:07:19,920 sugar water in, in, in whatever shape or form you can suggest 136 00:07:19,920 --> 00:07:22,240 it. And and and goes to quickest 137 00:07:22,240 --> 00:07:23,560 into the system, right? Yeah. 138 00:07:24,360 --> 00:07:27,520 Fantastic. Yeah, We, when we set up this 139 00:07:27,520 --> 00:07:30,080 whole thing with Scratch, I think they understood from our 140 00:07:30,080 --> 00:07:32,440 perspective that we don't think that there's one solution for 141 00:07:32,440 --> 00:07:35,280 everybody. A lot of people's stomachs or 142 00:07:35,280 --> 00:07:37,360 whatever are going to agree with some things more than others. 143 00:07:37,360 --> 00:07:40,800 So it was fun to hear what you had to say and what you like to 144 00:07:40,800 --> 00:07:43,360 use. And we have the same thing, by 145 00:07:43,360 --> 00:07:45,160 the way, on footwear and and some of that stuff. 146 00:07:45,160 --> 00:07:47,480 And so we'll talk and we'll talk about the fallacy of single 147 00:07:47,480 --> 00:07:49,080 trials. But it's the same thing with 148 00:07:49,320 --> 00:07:52,600 human beings that there isn't really one best option for 149 00:07:52,600 --> 00:07:54,080 everyone. Everybody responds really 150 00:07:54,080 --> 00:07:56,840 differently and think some of your research has shown that, 151 00:07:56,840 --> 00:07:58,800 which is really cool. All right, so here we go. 152 00:07:58,800 --> 00:08:01,560 Let's get into the meat and potatoes of this episode. 153 00:08:01,760 --> 00:08:04,760 Let's talk 1st about this idea of the fallacy of single trials, 154 00:08:04,760 --> 00:08:07,200 which was actually the name of an article that was published in 155 00:08:07,200 --> 00:08:10,240 the Journal of Sports Medicine in January of this year, January 156 00:08:10,240 --> 00:08:12,840 2024. So first, can you just tell us 157 00:08:12,840 --> 00:08:15,440 what inspired the writing of this article for you? 158 00:08:15,840 --> 00:08:19,560 Yeah, so, so there were a couple of different things happening at 159 00:08:19,560 --> 00:08:23,720 the same time, but I think there was one big inspiration to this 160 00:08:23,720 --> 00:08:27,880 article per SE was that and and you've probably talked about 161 00:08:27,880 --> 00:08:32,480 this article, but there's been studies more recently. 162 00:08:32,480 --> 00:08:35,080 So sort of there's different things going on, right? 163 00:08:35,080 --> 00:08:39,159 So everybody is sort of trying to find out who is a responder, 164 00:08:39,159 --> 00:08:43,559 what explains a responder. And then also there is this talk 165 00:08:43,559 --> 00:08:48,720 about super responders, hyper responders, under responders, 166 00:08:48,720 --> 00:08:52,880 non responders. And, and a lot of that sort of 167 00:08:55,080 --> 00:08:58,600 information is, is, is, is interesting. 168 00:08:58,920 --> 00:09:02,760 But there were some studies that were getting a lot of attention 169 00:09:03,760 --> 00:09:08,960 showing or indicating that some of these East African runners 170 00:09:08,960 --> 00:09:14,120 had benefits up to 11% in one shoe or 11% the other shoe. 171 00:09:14,680 --> 00:09:19,880 And upon close inspection of of that article and other articles, 172 00:09:20,480 --> 00:09:23,440 we realized that a lot of people are are making these responder 173 00:09:23,440 --> 00:09:29,280 claims based on just a single running economy measurement in 174 00:09:29,280 --> 00:09:34,600 that shoe, which sort of traditionally has been done when 175 00:09:34,600 --> 00:09:38,480 you look at the group level. But when you you start to look 176 00:09:38,480 --> 00:09:45,840 at it at an individual level, it's often probably not good 177 00:09:45,840 --> 00:09:51,600 enough data to make bold claims. So that sort of set the stage 178 00:09:51,600 --> 00:09:54,800 for us. And then we have always been 179 00:09:54,800 --> 00:09:59,120 doing at least two trials in the same shoe within the same block 180 00:09:59,120 --> 00:10:00,840 of measurements within the same visit. 181 00:10:01,760 --> 00:10:04,760 And then for the Nike study, the 4% study you talked about, we, 182 00:10:04,760 --> 00:10:08,200 we did that twice in each shoe within the same test. 183 00:10:08,200 --> 00:10:10,120 And then we did three days at different speeds, right. 184 00:10:10,120 --> 00:10:14,240 So we, we tested these people at least six times in each of these 185 00:10:14,240 --> 00:10:16,040 shoes. And then we took the average of 186 00:10:16,040 --> 00:10:20,800 the whole group and that came out to be that number versus now 187 00:10:20,800 --> 00:10:24,040 you see that some studies just put somebody in one shoe once 188 00:10:24,080 --> 00:10:26,760 and then again in another shoe, they take that number and say 189 00:10:26,760 --> 00:10:30,600 for you personally based on our test, this is your number. 190 00:10:31,160 --> 00:10:34,480 And that's where we're like, well, just step back here a 191 00:10:34,480 --> 00:10:36,880 little. Just think about what are we 192 00:10:36,880 --> 00:10:38,960 measuring? How are we measuring it? 193 00:10:40,160 --> 00:10:43,000 What are the measurement errors that the machine makes? 194 00:10:43,000 --> 00:10:46,040 What's the physiological variability of people running on 195 00:10:46,040 --> 00:10:49,800 a treadmill? These are all things that are 196 00:10:49,800 --> 00:10:53,280 important. And as a field moving forward, 197 00:10:53,280 --> 00:10:57,080 we, we should pay attention to what we do in those studies and 198 00:10:57,080 --> 00:11:01,080 be a little more careful by putting up a number based on 199 00:11:01,080 --> 00:11:03,880 just a one time in one shoe, one time in another shoe. 200 00:11:04,800 --> 00:11:07,680 Other studies have been doing one time in one shoe on a day 201 00:11:07,680 --> 00:11:10,520 one and then a week later in another shoe that has other 202 00:11:10,520 --> 00:11:13,080 issues with the measurement equipment that we're using. 203 00:11:13,080 --> 00:11:17,720 It's not necessarily perfectly comparable from one day to the 204 00:11:17,720 --> 00:11:21,560 other because of environmental conditions or just calibration 205 00:11:21,560 --> 00:11:24,120 of the system. So all of those sort of things 206 00:11:25,160 --> 00:11:29,720 inspire this for us to sort of say like, hey, let's all step 207 00:11:29,720 --> 00:11:32,240 back and think about how we do this and make sure we do this 208 00:11:32,240 --> 00:11:35,720 carefully. And if we do not have time to do 209 00:11:35,720 --> 00:11:39,080 it carefully, just don't make too bold of a claim. 210 00:11:40,720 --> 00:11:43,440 And then funny enough, when we started doing that, we found out 211 00:11:43,440 --> 00:11:45,720 that people have been saying this for over 40 years. 212 00:11:45,720 --> 00:11:48,280 When they started doing the first shoe studies, they already 213 00:11:48,280 --> 00:11:52,160 knew that. But as you, you probably know 214 00:11:52,160 --> 00:11:55,720 too, like sometimes it's hard to get to those old papers. 215 00:11:55,720 --> 00:11:58,840 People don't always have the time to read all the classics. 216 00:11:59,400 --> 00:12:01,360 So this sort of started to, to disappear. 217 00:12:01,360 --> 00:12:05,720 So we were just said, OK, let's remind everybody about what we 218 00:12:05,720 --> 00:12:08,920 know already for 40 years, that if you're going to look at an 219 00:12:08,920 --> 00:12:12,960 individual response of 1 runner, you have to have to do a couple 220 00:12:12,960 --> 00:12:18,400 of repeats in the same shoes before you decide or or or 221 00:12:18,400 --> 00:12:20,360 calculate what what their number is. 222 00:12:20,960 --> 00:12:23,800 And I have some follow up questions on that, but before I 223 00:12:23,800 --> 00:12:27,520 even ask those, if we state take another step backwards and just 224 00:12:27,520 --> 00:12:31,120 for people who may not be steeped in reading literature 225 00:12:31,120 --> 00:12:35,160 and some of the language used here, how would you define what 226 00:12:35,160 --> 00:12:38,360 fallacy of single trials really means for again, somebody who's 227 00:12:38,360 --> 00:12:40,160 not like in the research world? Yeah. 228 00:12:40,160 --> 00:12:44,040 So, so basically it's, it's a single trial would be if you 229 00:12:44,040 --> 00:12:49,560 just take one measurement. And so a single trial, running 230 00:12:49,560 --> 00:12:52,520 economy trial in our case when we talk about running footwear, 231 00:12:52,520 --> 00:12:55,400 running economy when we talk about other scenarios, but 232 00:12:55,680 --> 00:12:59,080 that's often what we do. Maybe in your case too, if you 233 00:12:59,080 --> 00:13:02,160 look at running bio mechanics and injury risk factors sort of 234 00:13:02,160 --> 00:13:06,360 the same thing. If you just take one snapshot, 235 00:13:06,440 --> 00:13:13,400 one single trial, you might not get to the actual answer. 236 00:13:13,400 --> 00:13:18,640 It's sort of the measure, measure twice got one's approach 237 00:13:18,640 --> 00:13:19,960 right. That's the saying. 238 00:13:19,960 --> 00:13:23,960 And and that saying is there just you want to measure twice. 239 00:13:23,960 --> 00:13:27,560 And and that's basically the whole story of this article is, 240 00:13:27,560 --> 00:13:33,240 is basically the same like we want to take a couple of 241 00:13:33,240 --> 00:13:36,760 measurements in our case running economy, which is oxygen uptake, 242 00:13:36,760 --> 00:13:40,600 which is combined on the air that you breathe out. 243 00:13:40,600 --> 00:13:44,680 So we measure air flow. So the airflow sensor is 244 00:13:44,680 --> 00:13:46,640 actually pretty hard to measure airflow. 245 00:13:46,640 --> 00:13:51,760 So there is some measurement, estimation, calibration stuff 246 00:13:51,760 --> 00:13:54,480 going on there. And then from the air that you 247 00:13:54,480 --> 00:13:57,840 breathe out, we measure the oxygen concentration and the 248 00:13:57,880 --> 00:14:00,520 CO2, carbon dioxide concentrates, right. 249 00:14:00,840 --> 00:14:04,480 And those again are are also measures that have some 250 00:14:04,480 --> 00:14:06,080 measurement error. It's not as simple as just a 251 00:14:06,080 --> 00:14:10,480 tape measure that you put to something and and get the exact 252 00:14:10,480 --> 00:14:13,200 number and it doesn't change if you do it again with the same 253 00:14:13,200 --> 00:14:16,680 tape measure. It's about telling these oxygen 254 00:14:16,680 --> 00:14:21,800 sensors, this is our tank air and this should be 4% and this 255 00:14:21,800 --> 00:14:28,520 is room air and it should be 0% or 0.04% of CO2. 256 00:14:28,520 --> 00:14:30,040 And then we calibrated against it. 257 00:14:30,040 --> 00:14:34,960 So all of that it's, it's a little more complicated to 258 00:14:34,960 --> 00:14:38,920 calibrate all these systems. And since all of those sensors 259 00:14:38,960 --> 00:14:42,120 and their information go into this running economy measure, 260 00:14:43,720 --> 00:14:47,360 we, we're, we're not really able to get a precise measurement 261 00:14:47,360 --> 00:14:50,880 every time we do it. So that's what what we're 262 00:14:50,880 --> 00:14:53,560 warning people for with evaluating the studies. 263 00:14:55,120 --> 00:14:56,600 And, and sometimes it's fine, right. 264 00:14:56,600 --> 00:15:00,520 If you, if you do a study with 40 people and they all do one 265 00:15:00,520 --> 00:15:03,120 trial in one shoe and all do one in the other. 266 00:15:03,120 --> 00:15:07,480 And you say on average, this whole group saw a 2% difference, 267 00:15:08,640 --> 00:15:11,400 then I'm I'm fine with that number. 268 00:15:12,280 --> 00:15:15,520 But if we didn't going to say, well, well this person had 7% 269 00:15:15,520 --> 00:15:20,120 and this person had 93%, then I'm like, well, if you want to 270 00:15:20,120 --> 00:15:22,280 make that claim, you have to test that person a couple of 271 00:15:22,280 --> 00:15:25,320 times to make sure that that was actually 7 and that the other 272 00:15:25,320 --> 00:15:30,160 one was actually 93. And it wasn't because of sensor 273 00:15:30,160 --> 00:15:32,800 drift or physiological drift or things like that. 274 00:15:33,400 --> 00:15:35,840 Yeah. And so how confident do you feel 275 00:15:35,840 --> 00:15:38,240 when you're performing these studies that if you get, so it 276 00:15:38,240 --> 00:15:40,640 sounds like you do 2 trials within a single session. 277 00:15:41,000 --> 00:15:44,840 How confident do you feel after getting those two or if they're 278 00:15:45,160 --> 00:15:47,800 very disparate for me, not more from one another, do you do a 279 00:15:47,800 --> 00:15:50,840 third or how do you handle that kind of information? 280 00:15:51,640 --> 00:15:53,040 Yeah, that's an excellent question. 281 00:15:53,040 --> 00:15:55,520 And kind of the, the reviewers of the article were kind of 282 00:15:55,600 --> 00:15:58,160 pushing us to, to make that claim other than just saying 283 00:15:58,160 --> 00:16:00,480 like, hey, we should be doing more than one. 284 00:16:00,920 --> 00:16:04,000 They wanted us to say like, but how many do we do then and 285 00:16:04,000 --> 00:16:05,960 there? It really comes down to sort of 286 00:16:06,520 --> 00:16:09,800 your, your answer too. And or your suggestion is like, 287 00:16:11,440 --> 00:16:15,040 I, I still would feel a little uncomfortable just doing 2. 288 00:16:15,040 --> 00:16:17,840 If I want to look at correlations between the 289 00:16:17,840 --> 00:16:20,320 responses and, and other measures. 290 00:16:21,120 --> 00:16:24,240 Again, if we do it at the group level, I think 2:00 is fine. 291 00:16:25,720 --> 00:16:30,440 But yeah, and, and, and sometimes we do tests where I 292 00:16:30,440 --> 00:16:34,280 think I'm probably one of the participants where my numbers 293 00:16:34,280 --> 00:16:38,800 are pretty much like let's say for the 4% study, it's always 4% 294 00:16:39,040 --> 00:16:43,200 and it varies between 4 point O1 and or 4.1 and 3.9. 295 00:16:43,800 --> 00:16:47,680 But we have other people in the lab where when we measured them, 296 00:16:47,680 --> 00:16:51,800 it it it that same example would range from 2:00 to 6:00 and it's 297 00:16:51,800 --> 00:16:53,600 the same person. They just do it twice. 298 00:16:54,880 --> 00:17:00,360 So I, I think if doing 2 trials taken to Everett is is OK. 299 00:17:00,360 --> 00:17:04,920 But if you really want to make bolder claims, you might want to 300 00:17:05,040 --> 00:17:07,920 do a third trial like you said, or repeat it on another day. 301 00:17:09,160 --> 00:17:11,720 And it sounds especially when you're making decisions on the 302 00:17:11,720 --> 00:17:14,560 level of the individual, that becomes even more important. 303 00:17:14,640 --> 00:17:18,119 I know for us as PTS, we work one-on-one with people. 304 00:17:18,319 --> 00:17:20,680 That's our job. And then so both of us are 305 00:17:20,680 --> 00:17:22,760 professors in physical therapy programs. 306 00:17:23,000 --> 00:17:25,359 And so when I'm working with students and we're in our clinic 307 00:17:25,359 --> 00:17:28,600 on campus and we're doing handheld dynamometry strength 308 00:17:28,600 --> 00:17:30,720 measurements, we, we start with two. 309 00:17:30,920 --> 00:17:33,880 And if there's a greater gap then and this is just for 310 00:17:34,040 --> 00:17:36,360 clinical efficiency, but if there's a greater gap than like 311 00:17:36,360 --> 00:17:39,560 10%, hey, let's do another one and see what where it's starting 312 00:17:39,560 --> 00:17:42,760 to come closer to. And it sounds somewhat similar 313 00:17:42,760 --> 00:17:45,640 from a reasoning standpoint of how you go about those 314 00:17:45,640 --> 00:17:48,280 decisions, especially at the level of the individual. 315 00:17:48,280 --> 00:17:51,800 Exactly. And and for our work in a 316 00:17:51,800 --> 00:17:54,760 scientific study it, it often has to be sort of predefined and 317 00:17:54,760 --> 00:17:57,640 more controlled like that. But if we do have somebody come 318 00:17:57,640 --> 00:18:01,320 in who is considering a contract with the new company and they 319 00:18:01,320 --> 00:18:05,240 want to see like how do these shoes compared to others? 320 00:18:05,520 --> 00:18:11,000 If we would get two times like 3.9 and 4.1, we are like, OK, 321 00:18:11,000 --> 00:18:15,400 this is probably going to be 4%. If we get two and seven or let's 322 00:18:15,400 --> 00:18:18,120 say that would still be better. But let's say we get a -, 2 and 323 00:18:18,120 --> 00:18:22,560 a + 2, we would do that third trial to make sure to or to get 324 00:18:22,560 --> 00:18:25,880 a better idea because we never were going to be sure which one 325 00:18:25,880 --> 00:18:30,080 is more likely to be better. So kind of like you do that too 326 00:18:30,080 --> 00:18:32,520 when, when you see that the two individual measures vary too 327 00:18:32,520 --> 00:18:35,520 much. Now again, if we do a full blown 328 00:18:35,880 --> 00:18:39,000 scientific study into some of these questions, we probably set 329 00:18:39,000 --> 00:18:44,480 it up ahead of time and decide we will test everybody 2 * 4 * 2 330 00:18:44,480 --> 00:18:46,280 times on different days, things like that. 331 00:18:46,360 --> 00:18:50,360 Yeah, that makes sense. And when you see somebody who 332 00:18:50,360 --> 00:18:53,680 has the kind of 2% on one trial and then the next one in that 333 00:18:53,680 --> 00:18:57,600 same day at 7:00, what in your mind usually accounts for those 334 00:18:57,600 --> 00:19:00,120 differences in in somebody's testing? 335 00:19:00,640 --> 00:19:02,080 Yeah. So there's a couple of different 336 00:19:02,080 --> 00:19:07,000 things that go into this. So if it's within a single day, 337 00:19:07,000 --> 00:19:10,400 within a single visit, it might be an order of fact, right? 338 00:19:10,400 --> 00:19:17,160 So if your first trial is in shoe A and then then you run in 339 00:19:17,160 --> 00:19:20,840 shoe B and then you run in shoe B and then in A. 340 00:19:21,480 --> 00:19:23,120 And then we look at the individual values. 341 00:19:23,120 --> 00:19:27,640 It might sometimes be that the first value in A might have been 342 00:19:27,640 --> 00:19:29,840 too low if they didn't properly warm up. 343 00:19:31,520 --> 00:19:35,120 Or if this whole thing involves now four different shoes and 344 00:19:35,120 --> 00:19:40,960 we're talking about a BCDDCBA by the time that they're back in A, 345 00:19:42,160 --> 00:19:44,360 there might be some physiological drift over this 346 00:19:44,800 --> 00:19:49,360 one hour 20 period, but also some sensor drift, right. 347 00:19:49,360 --> 00:19:53,200 So I told you we, we have the sensor that measures airflow and 348 00:19:53,200 --> 00:19:56,280 oxygen concentration. We calibrate these at the start 349 00:19:56,280 --> 00:20:01,440 of the experiment, but by the time the experiment, over 1 1/2 350 00:20:01,440 --> 00:20:06,280 hours later, the settings that we calibrated might not fully 351 00:20:06,280 --> 00:20:09,080 apply anymore. Either because there is a 352 00:20:09,080 --> 00:20:12,280 voltage drift in the sensor or even in the room. 353 00:20:12,280 --> 00:20:16,920 There's some physiological changes with total oxygen in the 354 00:20:16,920 --> 00:20:19,160 room or CO2 build up or things like that. 355 00:20:19,160 --> 00:20:23,320 Which again, we in our lab always try to control for those 356 00:20:23,320 --> 00:20:28,160 things as best as we can. But that doesn't always 357 00:20:28,160 --> 00:20:31,120 necessarily happen. I can't look into what other 358 00:20:31,120 --> 00:20:32,960 people doing in their lab all the time. 359 00:20:34,680 --> 00:20:40,200 And then obviously we just assume that those things are all 360 00:20:40,200 --> 00:20:44,400 taken care of. But when we see extremely high 361 00:20:44,400 --> 00:20:48,360 numbers, I usually know something was up and it might 362 00:20:48,360 --> 00:20:53,360 even be coming down to the fact that the air, the air hose was 363 00:20:53,720 --> 00:20:57,920 leaking or things like that, which obviously is a problem 364 00:20:57,920 --> 00:21:00,200 then, right? So if that happens, we say like, 365 00:21:00,200 --> 00:21:04,200 OK, we have to throw this away and, and do it all over. 366 00:21:05,720 --> 00:21:09,080 I had that experience when I first did my very first study on 367 00:21:09,400 --> 00:21:13,960 running economy and in Colorado in 2009 for a master's thesis. 368 00:21:15,240 --> 00:21:18,440 The professor had been on a sabbatical and we just got back 369 00:21:18,440 --> 00:21:21,120 in the lab. And over that year, sort of the 370 00:21:21,120 --> 00:21:26,360 the plastic hoses had degraded. And turned out I had been using 371 00:21:27,360 --> 00:21:30,240 hoses with holes in them for a couple of the tests. 372 00:21:30,520 --> 00:21:34,240 And we had to do all of that again when we found that out. 373 00:21:34,240 --> 00:21:36,280 But oh. That's frustrating. 374 00:21:38,000 --> 00:21:40,800 Wow. And can you explain what 375 00:21:40,800 --> 00:21:44,760 physiological drift means? Is that within somebody's own 376 00:21:44,760 --> 00:21:48,040 Physiology or is that the the environmental factors you're 377 00:21:48,040 --> 00:21:52,120 talking about? So the the physiological drift 378 00:21:52,120 --> 00:21:55,280 is sort of the umbrella term for what happens within the body. 379 00:21:55,280 --> 00:22:02,160 So one thing which could happen which most studies nowadays 380 00:22:02,160 --> 00:22:05,160 account for, but if you would just purely measure oxygen 381 00:22:05,160 --> 00:22:07,520 uptake, right, we're talking about VO2 now. 382 00:22:07,520 --> 00:22:10,160 We're not talking about metabolic power or metabolic 383 00:22:10,160 --> 00:22:14,240 rate, which sort of takes you to account CO2 production as well. 384 00:22:14,440 --> 00:22:21,040 But we're actually doing that because some of the times during 385 00:22:21,040 --> 00:22:25,240 this test, right? So before we go test, we, we ask 386 00:22:25,240 --> 00:22:28,360 people do not eat or drink anything for at least two hours. 387 00:22:28,360 --> 00:22:31,440 Some people prefer to test early in the morning after an 388 00:22:31,440 --> 00:22:35,880 overnight fast. So those, those people are 389 00:22:36,400 --> 00:22:39,280 probably in a steady state physiologically. 390 00:22:40,360 --> 00:22:44,480 But if it's just a 2 hour fasting and they had a lunch 391 00:22:44,800 --> 00:22:49,720 earlier, then they come in at 4:00 PM or something. 392 00:22:49,720 --> 00:22:53,600 And then over that hour there they're sort of sort of starting 393 00:22:53,600 --> 00:22:56,800 to get hungry. And sort of the, the, the 394 00:22:56,800 --> 00:23:01,320 physiological digestive system sort of starts to scale down on 395 00:23:01,640 --> 00:23:05,040 sugary or glucose utilization and more fatty acids. 396 00:23:05,240 --> 00:23:08,960 So we sort of see a drift in substrate utilization from 397 00:23:10,000 --> 00:23:12,360 glucose, glycogen to fatty acids. 398 00:23:13,120 --> 00:23:18,360 And if you use that oxygen to burn the fatty acids, you're 399 00:23:18,360 --> 00:23:21,720 actually getting more or you're getting less energy. 400 00:23:21,720 --> 00:23:24,560 You're getting more energy out of a gram of fatty acids, but 401 00:23:24,560 --> 00:23:27,520 you're getting less energy per unit of oxygen. 402 00:23:29,000 --> 00:23:31,400 So if you just look at the oxygen numbers, those might be 403 00:23:31,400 --> 00:23:35,840 changing over that period, but taking into account also the CO2 404 00:23:35,840 --> 00:23:38,280 production, we can now tell like, oh, this person is 405 00:23:38,280 --> 00:23:41,320 actually still using the same amount of energy. 406 00:23:41,320 --> 00:23:45,040 They're just using the oxygen now to burn more carbs or less 407 00:23:45,040 --> 00:23:46,520 carbs. And that's why the numbers go in 408 00:23:46,520 --> 00:23:51,280 different directions. But then so that's one example 409 00:23:51,280 --> 00:23:54,480 which most labs will have taken into account. 410 00:23:54,480 --> 00:23:57,800 Nowadays, they report metabolic rate taking those things into 411 00:23:57,800 --> 00:24:00,600 account. But it's also like, yeah, the 412 00:24:00,760 --> 00:24:04,400 body warming up, things like that. 413 00:24:04,400 --> 00:24:07,400 If you really have again the four shoes and you do twice of 414 00:24:07,400 --> 00:24:10,400 them, maybe there's some fatigue and some runners who aren't that 415 00:24:10,600 --> 00:24:14,880 well prepared to some of these shifts that are just happening 416 00:24:14,880 --> 00:24:18,200 and on the other side of sort of the warm up effect as well. 417 00:24:19,520 --> 00:24:25,200 So we don't necessarily know. We just know that it's not 418 00:24:25,200 --> 00:24:27,400 uncommon for some of these things to happen. 419 00:24:27,680 --> 00:24:30,400 And we know that because if you have somebody run eight times in 420 00:24:30,400 --> 00:24:33,800 the exact same shoe on the exact same treadmill at the exact same 421 00:24:33,800 --> 00:24:38,080 speed within the same session, we do see these changes 422 00:24:38,080 --> 00:24:40,200 happening. And it that's at that point, 423 00:24:40,600 --> 00:24:44,840 it's most likely, well, again, that could also be analyzer 424 00:24:44,840 --> 00:24:47,920 drift or room environmental drift. 425 00:24:47,920 --> 00:24:51,520 But that's why it's sort of capturing all of those things at 426 00:24:51,520 --> 00:24:54,720 once and and saying we should take this into account and 427 00:24:55,120 --> 00:24:57,600 measure a couple of times before we decide. 428 00:24:58,200 --> 00:25:00,640 So what I'm what I'm hearing alter this is great because it 429 00:25:00,640 --> 00:25:04,120 kind of confirms the intensely long effort it took for me to 430 00:25:04,120 --> 00:25:05,880 learn bio mechanics to do my study. 431 00:25:05,880 --> 00:25:08,040 It's just when you're a researcher and anybody that's 432 00:25:08,040 --> 00:25:10,440 reading research, you need to realize that there is going to 433 00:25:10,440 --> 00:25:13,040 be some level of error. And that's not a bad thing. 434 00:25:13,040 --> 00:25:15,000 It's just there's going to be variation. 435 00:25:15,000 --> 00:25:17,640 There's things that you also learn over time, which is why 436 00:25:17,680 --> 00:25:20,240 for me, I did a method study first, went, oh, I did all these 437 00:25:20,240 --> 00:25:22,880 things wrong, let's fix this. And you just have to realize 438 00:25:22,880 --> 00:25:25,720 that in the challenges, when you have a single study, there's 439 00:25:25,720 --> 00:25:28,600 going to be more of that versus when you have lots of different 440 00:25:28,600 --> 00:25:30,880 authors, lots of studies. It's kind of like the law of 441 00:25:30,880 --> 00:25:33,400 averages, where some, there's always going to be some level of 442 00:25:33,400 --> 00:25:35,800 error and some level of variance within the individual in the 443 00:25:35,800 --> 00:25:38,360 group. But the more evidence we have, 444 00:25:38,360 --> 00:25:41,280 we can be more confident. Whereas if you very careful, we 445 00:25:41,280 --> 00:25:46,720 do one trial, one studies is be cautious interpreting these 446 00:25:46,720 --> 00:25:49,240 things that I'm now I'm getting this as a newly minted PhD and 447 00:25:49,240 --> 00:25:52,120 understanding those who are far more experienced, where people 448 00:25:52,120 --> 00:25:55,840 are so careful to make any claims because like we all know, 449 00:25:55,840 --> 00:25:57,760 right? And that's just, that's just how 450 00:25:57,760 --> 00:25:59,920 research works. There's a lot this goes into US. 451 00:25:59,920 --> 00:26:03,120 People have to realize it takes a long time for a very intense 452 00:26:03,120 --> 00:26:05,400 reason because you have to work so hard just to get these 453 00:26:05,400 --> 00:26:07,560 results. But air and variation are 454 00:26:07,560 --> 00:26:09,880 totally normal. So be cautious with those single 455 00:26:10,000 --> 00:26:11,440 studies. Exactly. 456 00:26:11,440 --> 00:26:14,880 And I, I really like your example that that Nathan brought 457 00:26:14,880 --> 00:26:16,720 up about the handheld dynamometer, right. 458 00:26:16,720 --> 00:26:20,720 I think that that's another thing that intuitively you can 459 00:26:20,720 --> 00:26:22,880 see like if you do this once and you do it again, you're going to 460 00:26:22,880 --> 00:26:26,640 get a different number. And there's some bio mechanics 461 00:26:27,040 --> 00:26:29,560 things that we measure with the camera setup and a market 462 00:26:29,560 --> 00:26:32,720 placement on the body and the joint angles and that that can 463 00:26:32,720 --> 00:26:35,680 be really good and and reproducible. 464 00:26:36,320 --> 00:26:42,000 But running economy is is is not one of those measures that is 465 00:26:42,000 --> 00:26:48,640 super reproducible. So when you consider I, I almost 466 00:26:48,640 --> 00:26:50,360 have different categories in my head. 467 00:26:50,360 --> 00:26:53,960 But you know, when you, when you consider studies that utilize 468 00:26:53,960 --> 00:26:58,120 single trials or even if you are someone going to a lab to get 469 00:26:58,120 --> 00:27:01,640 your VO2 Max tested or you're running economy tested and 470 00:27:01,640 --> 00:27:05,080 you're trying different shoes. What are the risks of using 471 00:27:05,080 --> 00:27:09,480 single trials to either make decisions or whether that's for 472 00:27:09,480 --> 00:27:12,320 purchasing a shoe or what you wear for a race or I guess with 473 00:27:12,360 --> 00:27:15,200 athletes that you're working with, changing companies that 474 00:27:15,200 --> 00:27:17,360 you're going to maybe sponsorship with. 475 00:27:17,600 --> 00:27:19,760 What are some of the risks associated with only using 476 00:27:19,760 --> 00:27:23,600 single trials? Well, I, I think your, your 477 00:27:23,600 --> 00:27:25,680 question basically answers the question, right. 478 00:27:25,680 --> 00:27:33,520 So let's say we, we just do one test and we, we compare brand A 479 00:27:33,760 --> 00:27:39,120 against brand B and person comes into the lab, it's well 480 00:27:39,120 --> 00:27:42,840 calibrated and, and they're actually, let's say they want to 481 00:27:42,840 --> 00:27:47,080 buy a shoe in the store and they just, I don't know. 482 00:27:47,640 --> 00:27:50,600 I, I do not suggest people do this, but they order eight 483 00:27:50,600 --> 00:27:53,760 different models online. They bring them to the lab. 484 00:27:54,360 --> 00:27:58,520 They, they then do one trial in each of these eight. 485 00:27:58,960 --> 00:28:02,280 And then they go with the number that's the best and they return 486 00:28:02,280 --> 00:28:03,720 the other. So do not do that. 487 00:28:03,720 --> 00:28:11,200 That's not. But if you do that and you just 488 00:28:11,200 --> 00:28:17,280 pick the one trial with the best number because you only measured 489 00:28:17,280 --> 00:28:22,760 this once, there is a chance that you did not take the shoe 490 00:28:22,760 --> 00:28:24,920 that was best for you and you returned that one. 491 00:28:25,960 --> 00:28:30,200 So it could just be a purchasing decision, which is kind of low 492 00:28:30,200 --> 00:28:34,640 stakes. But yeah, once you're more and 493 00:28:34,640 --> 00:28:38,280 more elite overrunner, it's more important to have the best shoe 494 00:28:38,280 --> 00:28:40,120 for you. And you can get a better 495 00:28:40,120 --> 00:28:43,000 contract if you have a better performance in a better shoe. 496 00:28:43,480 --> 00:28:48,400 Or what we talked about, what we see more recently is that people 497 00:28:48,400 --> 00:28:51,280 have a sponsorship with one brand and they're considering 498 00:28:51,280 --> 00:28:54,040 switching brands. And then they just want to make 499 00:28:54,040 --> 00:28:59,880 sure that the the new company makes shoes that are at least as 500 00:28:59,880 --> 00:29:03,000 good or ideally even better than the shoes with the company that 501 00:29:03,000 --> 00:29:04,240 they're currently running for, right? 502 00:29:04,240 --> 00:29:07,520 So those are high stake decisions. 503 00:29:07,520 --> 00:29:11,880 So you probably don't want to go to a lab and run in each of 504 00:29:11,880 --> 00:29:16,120 these shoes once. And let's say you run, that's 505 00:29:16,120 --> 00:29:20,000 another thing to consider. If you run in that, let's say at 506 00:29:20,000 --> 00:29:24,680 a 14 kilometre per hour or seven minute mile pace, but you're 507 00:29:24,680 --> 00:29:27,960 actually sort of this sub elite person who's running their races 508 00:29:27,960 --> 00:29:31,840 at 18 kilometers per hour or 520 mile pace. 509 00:29:33,320 --> 00:29:37,120 You probably want to test it as close enough to your marathon 510 00:29:37,120 --> 00:29:40,880 race pace. But if you if you do that, you 511 00:29:40,880 --> 00:29:42,440 want to do that a couple of times. 512 00:29:44,120 --> 00:29:47,440 And I know several examples of people who have done exactly 513 00:29:47,440 --> 00:29:49,200 that, but they replicated our study. 514 00:29:49,480 --> 00:29:54,240 So they did it flies in each shoe at a speed close enough to 515 00:29:54,240 --> 00:29:58,920 their race pace of interest. And then the numbers were 516 00:29:59,560 --> 00:30:02,400 closely enough between the different trials to to make a 517 00:30:02,400 --> 00:30:07,160 clean decision. Or, or in the case that it 518 00:30:07,160 --> 00:30:10,920 wouldn't be the case, they could then just say like, OK, either 519 00:30:11,160 --> 00:30:14,880 it doesn't matter which of these brands or I need to test this 520 00:30:14,880 --> 00:30:16,280 again if I really want to be sure. 521 00:30:18,160 --> 00:30:21,400 But yeah, so those are very specific examples for people who 522 00:30:21,400 --> 00:30:24,520 have access to these labs. And there's more and more of 523 00:30:24,520 --> 00:30:26,760 these labs, but they don't always have the best equipment, 524 00:30:26,760 --> 00:30:30,080 which means that there's more likelihood of errors being made 525 00:30:30,080 --> 00:30:34,880 in that assessment too. And then for us as scientists, 526 00:30:35,640 --> 00:30:40,040 if we want to explain why Nathan is a super responder with his 7% 527 00:30:40,040 --> 00:30:43,320 and Matt is a mediocre responder with his 1%. 528 00:30:43,880 --> 00:30:46,920 And we're going to do a correlation between their size 529 00:30:46,920 --> 00:30:51,920 of their calves muscles and their body weight and their foot 530 00:30:51,920 --> 00:30:56,520 strength and their casual running speeds or their race 531 00:30:56,520 --> 00:31:00,160 speeds. Now we're we're going to try to 532 00:31:00,160 --> 00:31:04,960 explain the difference between one and 7% and there's a 533 00:31:04,960 --> 00:31:09,120 hundreds of candidate variables that go into this. 534 00:31:10,080 --> 00:31:13,960 And then we might say like, oh, this is all about calf muscle 535 00:31:13,960 --> 00:31:16,720 strength. And now if you really want to 536 00:31:16,720 --> 00:31:19,200 know whether you should be running in shoe A or B, you 537 00:31:19,200 --> 00:31:22,120 should do this calf muscle test. Because if you're strong enough, 538 00:31:22,120 --> 00:31:25,080 you should run in B. And if not like math, then you 539 00:31:25,080 --> 00:31:28,040 should be running in in A. I'm not inferring that math has 540 00:31:28,040 --> 00:31:30,800 weaker calf muscles. This is just the example. 541 00:31:32,360 --> 00:31:37,720 But yeah, so that's where why we really wrote this article for 542 00:31:37,720 --> 00:31:40,920 the field to realize this, because people are doing are 543 00:31:40,920 --> 00:31:44,600 trying to do these analysis. And I don't want people start 544 00:31:44,600 --> 00:31:49,920 chasing in the wrong direction based on and we we can only do 545 00:31:49,920 --> 00:31:53,120 these analysis if we test hundreds of people. 546 00:31:53,120 --> 00:31:57,080 And you can't have hundreds of people doing 40 shoes twice, 547 00:31:57,080 --> 00:31:59,440 right? So there has to be some give or 548 00:31:59,440 --> 00:32:03,080 take somewhere. But but we want to say make sure 549 00:32:03,080 --> 00:32:06,000 that that give or take is is probably not in how often you 550 00:32:06,000 --> 00:32:09,280 run in the same condition. You probably want to repeat 551 00:32:09,280 --> 00:32:11,360 that. Yeah, that's fantastic. 552 00:32:11,880 --> 00:32:14,760 And in this, in this whole sphere, knowing that there are 553 00:32:14,760 --> 00:32:18,640 studies that have been gone through with single trials and 554 00:32:18,840 --> 00:32:22,040 even just other studies in general, are there any specific 555 00:32:22,040 --> 00:32:25,920 studies or concepts that you'd like to be replicated that 556 00:32:25,920 --> 00:32:27,600 you've read or that you've done yourself? 557 00:32:28,560 --> 00:32:34,600 Yeah. So we have, we are currently and 558 00:32:34,600 --> 00:32:37,480 we have done in the past looking at sort of uphill running and 559 00:32:37,480 --> 00:32:40,160 sort of the the carbon fiber plate story there. 560 00:32:40,160 --> 00:32:43,240 And when you add different grades and you say you have 561 00:32:43,240 --> 00:32:48,840 level uphill and downhill then and you do it at 1 speed, but 562 00:32:48,840 --> 00:32:51,720 then you already have three grades and two shoes. 563 00:32:51,720 --> 00:32:54,600 That's already 6 trials. And you probably don't want to 564 00:32:54,600 --> 00:32:57,280 be doing more than six or eight trials in a visit because of 565 00:32:57,280 --> 00:33:00,720 the, the analyzer drift, which we talked about sensor drift. 566 00:33:02,200 --> 00:33:05,040 So then so we did that study. I think it was fine because 567 00:33:05,040 --> 00:33:06,560 again, it was a group level thing. 568 00:33:07,640 --> 00:33:11,080 But now we're going with our steep shrapnel sort of 569 00:33:11,080 --> 00:33:13,360 revisiting this question and saying like, well, it's really 570 00:33:13,360 --> 00:33:14,720 steep. At some point this plate's going 571 00:33:14,720 --> 00:33:19,160 to be getting in the way. But then we did more grades and 572 00:33:19,160 --> 00:33:22,480 we did it once. And now we do see like among the 573 00:33:22,480 --> 00:33:24,400 group level, it's not super clear. 574 00:33:25,240 --> 00:33:28,640 So now we're actually sort of restarting the study and say 575 00:33:28,640 --> 00:33:31,360 like, OK, let's just do level and super steep, forget about 576 00:33:31,360 --> 00:33:34,920 the intermediate grades, but do repetitions on the level and do 577 00:33:34,920 --> 00:33:40,280 repetitions on the steep grade. So, so that's sort of one 578 00:33:40,280 --> 00:33:44,600 example where we, we realized that we would have more 579 00:33:44,600 --> 00:33:48,360 statistical power by by averaging multiple trials, I 580 00:33:48,360 --> 00:33:51,320 think in the fields. Well, I already mentioned the, 581 00:33:51,400 --> 00:33:57,520 the 11% observations and I'm not super fan of that one. 582 00:33:57,520 --> 00:34:02,800 And, and interesting for me recently and I read that the, 583 00:34:03,080 --> 00:34:05,360 the authors of that study also acknowledged that not all of 584 00:34:05,360 --> 00:34:07,160 these runners had a lot of experience running on the 585 00:34:07,160 --> 00:34:09,199 treadmill and they only did one trial. 586 00:34:09,199 --> 00:34:12,159 So they sort of were aware of that limitation. 587 00:34:12,800 --> 00:34:17,080 But now for me, it's sort of like, well, what's it saying 588 00:34:17,080 --> 00:34:20,400 that is the genius out of the bottle is at it or? 589 00:34:20,400 --> 00:34:24,080 Yeah, so it's already out there. Yeah, so so. 590 00:34:24,239 --> 00:34:25,840 You can't, you can't take that all back. 591 00:34:25,920 --> 00:34:29,480 Like people have thought about it and digested that information 592 00:34:29,480 --> 00:34:33,400 and. Yeah, so, so so that one and 593 00:34:33,400 --> 00:34:35,880 then there's just been other ones again like they tested 100 594 00:34:35,880 --> 00:34:37,480 people. They they sort of split them up 595 00:34:37,480 --> 00:34:40,080 in responders and non responders and saw that speed was a big 596 00:34:40,080 --> 00:34:43,239 effect. And I think when you talk about 597 00:34:43,239 --> 00:34:47,520 that, just the fact that you have 100 people, for me, it's, 598 00:34:47,520 --> 00:34:50,280 it's, it's, it's OK. So I don't necessarily think 599 00:34:50,280 --> 00:34:52,480 that's going to be easy to replicate that. 600 00:34:54,199 --> 00:34:58,640 So I think it's just more moving forward, people need to keep 601 00:34:58,640 --> 00:35:02,720 that in mind and, and know that if there's studies that make 602 00:35:02,720 --> 00:35:07,560 these claims or inferences, just verify if, if, where does it 603 00:35:07,560 --> 00:35:09,920 come from? And this is just first 604 00:35:09,920 --> 00:35:13,600 indication and we should follow up with more rigorous research 605 00:35:13,600 --> 00:35:19,960 to test this specific hypothesis versus something that already 606 00:35:20,080 --> 00:35:26,720 has been carefully, elaborately executed and then we can be a 607 00:35:26,720 --> 00:35:29,600 little more confident in actual finding of study like that. 608 00:35:30,520 --> 00:35:32,280 It's harder. It's harder to teach the public 609 00:35:32,280 --> 00:35:35,760 this, but for my PT students, for example, that's why you 610 00:35:35,760 --> 00:35:39,560 always have to be very cautious when you see a single study, 611 00:35:39,560 --> 00:35:43,280 especially one that stands out and is so different than others. 612 00:35:43,560 --> 00:35:46,480 You always have to ask how they do this. 613 00:35:46,480 --> 00:35:48,760 So for the students I work with, one of the first thing you tell 614 00:35:48,760 --> 00:35:51,520 them learning to read research, don't just read the abstract is 615 00:35:51,520 --> 00:35:54,160 go read the methods first. It's hard for the public to do 616 00:35:54,160 --> 00:35:56,560 this. We try to, we try to clarify 617 00:35:56,560 --> 00:35:58,760 that and be cautious. But if you see immediately in 618 00:35:58,760 --> 00:36:01,160 the methods like there's going to be this or this or like, what 619 00:36:01,160 --> 00:36:03,240 are you doing? Often times it'll just stop 620 00:36:03,240 --> 00:36:04,920 reading because I'm like, I, I can't really take any 621 00:36:04,920 --> 00:36:08,240 conclusions from this because how you do things will certainly 622 00:36:08,240 --> 00:36:10,440 affect your results. But it's, again, I know I keep 623 00:36:10,440 --> 00:36:12,480 saying this, it's hard for the public to know how to digest 624 00:36:12,480 --> 00:36:13,960 that. So that's where your your study 625 00:36:13,960 --> 00:36:15,160 and talk about this is so helpful. 626 00:36:15,640 --> 00:36:18,240 Yeah. I think that we, we we talked in 627 00:36:18,240 --> 00:36:21,920 the study we cite, I think it's Carl Sagan who says like 628 00:36:22,520 --> 00:36:26,120 extraordinary claims require extraordinary evidence. 629 00:36:26,440 --> 00:36:31,040 And that sort of was something that I thought of right away 630 00:36:31,040 --> 00:36:36,280 when we saw the 11%. And if you and I'm not saying 631 00:36:36,280 --> 00:36:39,160 that it's not true, but at this point I have a hard time 632 00:36:39,160 --> 00:36:41,160 believing it. If they would test it again, 633 00:36:41,160 --> 00:36:45,800 same runner and they see it day after day, then then OK, OK, 634 00:36:45,840 --> 00:36:49,520 this is extraordinary and they have the extraordinary evidence 635 00:36:49,520 --> 00:36:53,440 to go with it. So, and, and that's also 636 00:36:53,440 --> 00:36:57,520 something we, when we did the original 4% study, were sort of 637 00:36:57,520 --> 00:36:59,600 aware of, right? We were like, OK, these shoes 638 00:36:59,600 --> 00:37:03,320 are actually for the first time in a very long time better than 639 00:37:03,680 --> 00:37:06,480 other shoes. And it seems that footwear can 640 00:37:06,480 --> 00:37:10,440 actually make a difference. So we were always focused on 641 00:37:10,440 --> 00:37:13,400 like, we need to do this as careful as we can. 642 00:37:13,400 --> 00:37:17,480 We need to make sure that once this is done, not nobody's going 643 00:37:17,480 --> 00:37:20,960 to say like, well, yeah, you, you just measured once. 644 00:37:23,240 --> 00:37:27,840 So we, we, we were aware that it was going to be high impact 645 00:37:27,840 --> 00:37:30,960 study. So we made sure we executed it 646 00:37:31,840 --> 00:37:36,920 very properly. And but again, I mean the 11% 647 00:37:36,920 --> 00:37:41,480 obviously wasn't set up to be a study into that, right. 648 00:37:41,480 --> 00:37:45,560 They just had the opportunity to test some elite runners that are 649 00:37:45,560 --> 00:37:48,120 way better than I have had that I had in my lab. 650 00:37:49,320 --> 00:37:52,560 And if you have that opportunity, you want to measure 651 00:37:52,560 --> 00:37:54,520 them right? And you probably want to tell 652 00:37:54,520 --> 00:37:58,280 others about what you saw. So I can see that it was from a 653 00:37:58,280 --> 00:38:02,040 different angle. But it's sort of hard to to to 654 00:38:02,040 --> 00:38:04,280 get the message clear. And, and like you said, to have 655 00:38:04,280 --> 00:38:06,720 for the general public to see like, OK, this is where it came 656 00:38:06,720 --> 00:38:10,280 from and this is what it might mean, but it it's at a different 657 00:38:10,280 --> 00:38:10,760 level. Yeah. 658 00:38:11,120 --> 00:38:13,920 Well, that's actually a great segue into kind of our next main 659 00:38:13,920 --> 00:38:17,040 topic, which is we've been dancing around it, but just that 660 00:38:17,040 --> 00:38:20,280 topic of super shoes or advanced footwear technology. 661 00:38:20,640 --> 00:38:22,520 And 1st, we just want to hear from you. 662 00:38:22,520 --> 00:38:27,480 How do you yourself define what a super shoe is or what advanced 663 00:38:27,480 --> 00:38:30,880 footwear technology is? It's interesting to to have a 664 00:38:30,880 --> 00:38:34,640 clear definition and there is has been some discussion about 665 00:38:34,760 --> 00:38:37,920 footwear researchers who then came up with the term advanced 666 00:38:37,920 --> 00:38:40,840 footwear technology, which I personally don't necessarily 667 00:38:40,840 --> 00:38:42,840 always like either just for the grammar. 668 00:38:42,840 --> 00:38:44,720 It's hard to deal with sometimes when you're right. 669 00:38:45,440 --> 00:38:52,960 But I think we it's it's basically anything since the 670 00:38:52,960 --> 00:38:58,520 Nike V5 four percent right. So it's I mean, there's the 671 00:38:58,520 --> 00:39:01,200 different components. So I think the most prominent 672 00:39:01,200 --> 00:39:06,400 ones for that's you were the softer, more resilient mid cell 673 00:39:06,400 --> 00:39:09,240 foam. Then there is this carbon fiber 674 00:39:09,240 --> 00:39:12,040 plate, which I think in the official scientific definition 675 00:39:12,040 --> 00:39:19,120 of AFT is, is a rigid moderator because obviously Adidas had 676 00:39:19,640 --> 00:39:22,400 their rods initially and I think their plates are still sort of 677 00:39:22,400 --> 00:39:25,920 more rod like. So you want to capture that. 678 00:39:26,520 --> 00:39:28,440 And then for foam, it was PBA foam. 679 00:39:28,440 --> 00:39:31,480 But now there's other ways to make fancy super foams. 680 00:39:32,720 --> 00:39:37,200 So it, it, it's generally just considered as a very soft and 681 00:39:37,200 --> 00:39:39,040 resilient, highly resilient foam. 682 00:39:39,920 --> 00:39:43,760 And then there is something with the rocker geometry too and the 683 00:39:43,760 --> 00:39:47,040 stack hide. But again, this is more like 684 00:39:47,160 --> 00:39:49,800 technological definitions of of what it is. 685 00:39:50,360 --> 00:39:59,200 I think for me it's it's usually a good amount of very bouncy 686 00:39:59,200 --> 00:40:01,360 foam. That's the most important 687 00:40:01,360 --> 00:40:03,480 ingredient scientifically. It's sometimes hard even because 688 00:40:03,480 --> 00:40:07,520 we do studies on on on super shoes, but then we leave out the 689 00:40:07,520 --> 00:40:09,760 plate and it's like, is it then no longer a super shoe? 690 00:40:09,760 --> 00:40:12,360 But well, we're trying to control it and we kind of want 691 00:40:12,360 --> 00:40:16,520 to talk about it in this context versus some of the original 692 00:40:16,520 --> 00:40:20,200 studies back in the early 2000s, they were also using plates, but 693 00:40:20,200 --> 00:40:23,480 that was all within an Eva foam or as an insole. 694 00:40:24,600 --> 00:40:29,040 So, so yeah, it's kind of. Varies, but I think most people 695 00:40:29,040 --> 00:40:33,240 know what a super shoe is when they see one or when they wear 696 00:40:33,240 --> 00:40:37,600 one. But I think for me the most 697 00:40:37,600 --> 00:40:39,880 important part is, is probably the bouncy foam. 698 00:40:39,880 --> 00:40:42,920 And it's not necessarily the chemical structure of that, but 699 00:40:42,920 --> 00:40:46,120 just the bounciness of it that that is very important. 700 00:40:46,360 --> 00:40:49,920 Yeah, Matt, you recently had an experience with with with that, 701 00:40:49,920 --> 00:40:51,400 right? I have to bring it up like every 702 00:40:51,400 --> 00:40:54,920 time because. Yeah, we're Walter. 703 00:40:54,920 --> 00:40:58,760 You did a great job of, you know, pulling away from where my 704 00:40:58,760 --> 00:41:03,320 error was, where I was like, oh, it can only be a Piba PBX based 705 00:41:03,320 --> 00:41:04,880 foam. And then Mizuno was like, 706 00:41:04,880 --> 00:41:07,280 actually that super bouncy foam that you're talking about that 707 00:41:07,280 --> 00:41:09,320 you love so much is is Eva based. 708 00:41:09,320 --> 00:41:14,240 And I was like, all right, so we let's pull back and talk about 709 00:41:14,240 --> 00:41:17,800 having a very like very compliant and resilient foam 710 00:41:17,800 --> 00:41:21,240 instead of defining the chemical structure because I am not a 711 00:41:21,240 --> 00:41:23,280 chemical engineer and that is outside of my scope. 712 00:41:23,280 --> 00:41:26,960 So let's just go with bouncy and and leave it at that. 713 00:41:27,840 --> 00:41:31,240 So I mean, I, I feel like we could ask you a million 714 00:41:31,240 --> 00:41:33,920 questions about like your, your take on lots of different 715 00:41:33,920 --> 00:41:36,720 things, but we're going to try to keep it somewhat concise here 716 00:41:36,720 --> 00:41:39,840 tonight, knowing that, especially that it's late over 717 00:41:39,840 --> 00:41:43,400 by you and you've started to talk about different components 718 00:41:43,400 --> 00:41:46,280 that make up kind of a shoe that's economical. 719 00:41:46,560 --> 00:41:49,800 And you started talking about the interaction between foams 720 00:41:49,800 --> 00:41:53,440 and plates in geometry. And you recently published a 721 00:41:53,440 --> 00:41:57,080 study that kind of explored that those relationships further. 722 00:41:57,080 --> 00:41:59,880 So in your, from your perspective and from that recent 723 00:41:59,880 --> 00:42:02,200 study, and you can tell us about that study, I guess a little bit 724 00:42:02,200 --> 00:42:05,800 more, what is the role of a plate or the foam or the 725 00:42:05,800 --> 00:42:08,200 geometry? Like how do those interact with 726 00:42:08,200 --> 00:42:10,200 each other? What's I'm going to say? 727 00:42:10,200 --> 00:42:13,000 What's the most important? Knowing that, that's a harder 728 00:42:13,000 --> 00:42:14,680 question. Yeah, I think that that was 729 00:42:15,000 --> 00:42:20,320 particularly in in 2017 eighteen 19 probably sort of the multi 730 00:42:20,360 --> 00:42:24,320 $1,000,000 question where Nike had dropped this shoe and 731 00:42:24,320 --> 00:42:27,280 everybody was like, OK, how can we make a similar shoe. 732 00:42:28,360 --> 00:42:32,080 And obviously the the big new component was the carbon fiber 733 00:42:32,080 --> 00:42:34,840 plate that got a lot of tension that that was sort of like 734 00:42:35,160 --> 00:42:38,640 coming from bikes coming people were making analogies to to 735 00:42:38,640 --> 00:42:40,800 running prestigious and things like that. 736 00:42:42,000 --> 00:42:45,240 So that always has sort of been sort of the, in some people's 737 00:42:45,240 --> 00:42:50,800 views, the bad, the bad guy and in other people's views, that 738 00:42:50,800 --> 00:42:53,000 would be sort of the, the magic sauce, right? 739 00:42:53,000 --> 00:42:56,480 But, and we from the start always had this interest in 740 00:42:56,480 --> 00:42:59,440 like, OK, what is the plate now doing and, and what's the foam 741 00:42:59,440 --> 00:43:03,960 doing? And sort of right from the 742 00:43:03,960 --> 00:43:09,080 start, we did several different tests and we have done a bunch 743 00:43:09,080 --> 00:43:12,000 of them by now. So the first thing we did with 744 00:43:12,000 --> 00:43:14,880 the original study, we had them vertically compressed and we saw 745 00:43:14,880 --> 00:43:18,720 that that foam is indeed very compliant and soft. 746 00:43:18,840 --> 00:43:22,960 It deforms a lot under load, but it's also very resilient, very 747 00:43:22,960 --> 00:43:24,800 bouncy. It returns a lot of that 748 00:43:24,800 --> 00:43:30,040 vertical force. So we can we quantified how much 749 00:43:30,040 --> 00:43:32,720 that would be under the normal body weight of somebody running 750 00:43:32,720 --> 00:43:37,600 at at a decent pace. And then in then we looked at 751 00:43:37,600 --> 00:43:39,880 the bio mechanics of sort of what happens with the shoe 752 00:43:39,880 --> 00:43:44,080 during toe off and sort of quantified how much flexion is 753 00:43:44,080 --> 00:43:47,080 there in toe off in the plate. And is the plate also 754 00:43:47,240 --> 00:43:51,680 functioning as a spring stirring that energy during just before 755 00:43:51,680 --> 00:43:54,320 toe off and then releasing it right at toe off right. 756 00:43:55,400 --> 00:43:58,440 And sort of using biomechanical approaches, we, we could 757 00:43:58,440 --> 00:44:00,360 quantify how much is the shoe flexing. 758 00:44:00,360 --> 00:44:04,240 We knew how stiff the shoe was in bending. 759 00:44:05,040 --> 00:44:07,280 So putting those numbers together, we sort of got an 760 00:44:07,280 --> 00:44:11,840 estimate of how much energy the, the, the shoe sole was storing 761 00:44:11,840 --> 00:44:15,600 and returning and bending. And at that point we, we sort 762 00:44:15,600 --> 00:44:18,560 of, I mean, we never looked inside the shoe, right? 763 00:44:18,560 --> 00:44:21,040 So this is all from the outside and putting things together. 764 00:44:21,360 --> 00:44:25,280 But that suggested that the vertical foam compression was 765 00:44:25,480 --> 00:44:29,400 returning 50 times as much energy than the bending and and 766 00:44:29,400 --> 00:44:33,600 straightening of the plate, which was already sort of 767 00:44:33,720 --> 00:44:36,640 suggesting that there's a lot more going on with the foam than 768 00:44:36,640 --> 00:44:38,320 what than with the plate at that time. 769 00:44:39,160 --> 00:44:44,920 Then when I started my lap here, Laura, I think who we've talked 770 00:44:44,920 --> 00:44:46,480 to before, did the cool study where? 771 00:44:46,480 --> 00:44:49,160 We've had her. On here we we cut the Faber Fly 772 00:44:49,160 --> 00:44:51,000 shoes. So we got through the plate 773 00:44:51,080 --> 00:44:53,400 taking out the bending stiffness off the plate. 774 00:44:53,680 --> 00:44:57,240 Everything else of the shoes was intact and we measured running 775 00:44:57,240 --> 00:45:00,280 economy and we basically saw no difference between an intact 776 00:45:00,560 --> 00:45:04,400 with the plate and the cut shoe where the bending stiffness was 777 00:45:05,080 --> 00:45:08,640 taken out. Again, suggesting that just the 778 00:45:08,640 --> 00:45:13,120 phone by itself seems to be a main player here. 779 00:45:13,720 --> 00:45:16,720 But we still weren't satisfied. So at the same time we were 780 00:45:16,720 --> 00:45:21,760 talking to people at Saucony and we were like, well, ideally we 781 00:45:21,760 --> 00:45:26,400 would have the Super shoe, the exact same shoe, but we get one 782 00:45:26,400 --> 00:45:32,280 version made out of PBA foam, PBA based foam, one out of sort 783 00:45:32,280 --> 00:45:34,880 of conventional traditional Eva foam. 784 00:45:35,320 --> 00:45:39,520 And then we have both of these shoes will have one without a 785 00:45:39,520 --> 00:45:42,680 plate and one with a plate. So now we have sort of our two 786 00:45:42,680 --> 00:45:47,200 by two version where in both foams we had with and without 787 00:45:47,200 --> 00:45:49,400 plate. Or if you look across the other 788 00:45:49,880 --> 00:45:53,840 way, we had we had with plate in different foams and we had 789 00:45:53,840 --> 00:45:55,600 without plate in different foams. 790 00:45:56,120 --> 00:46:00,840 And we always sort of thought that there was some sort of 791 00:46:00,840 --> 00:46:04,480 magic in, in, in this interaction between a plate and 792 00:46:04,480 --> 00:46:09,000 the foam that adding a plate to the foam would make the foam 793 00:46:09,000 --> 00:46:12,960 even work better or putting the foam around the plate would make 794 00:46:12,960 --> 00:46:15,120 the plate work better in, in some way. 795 00:46:15,120 --> 00:46:19,440 So for that study, we, we were, we have thought we're going to 796 00:46:19,440 --> 00:46:24,160 see just adding a plate is going to have a small effect. 797 00:46:24,760 --> 00:46:28,520 Just upgrading the foam is going to have a decent effect. 798 00:46:28,880 --> 00:46:31,920 But if you upgrade the foam and you add a plate, you're going to 799 00:46:31,920 --> 00:46:35,080 have even a better running economy. 800 00:46:36,160 --> 00:46:39,440 That's what we anticipated. Turned out that wasn't 801 00:46:39,440 --> 00:46:41,800 necessarily true. It was actually kind of opposite 802 00:46:41,800 --> 00:46:45,920 that either. Adding the plate was about a 1% 803 00:46:45,920 --> 00:46:49,080 improvement in running economy. Upgrading the foam was about a 804 00:46:49,080 --> 00:46:55,400 1%, but if we put them together they didn't add up to to more 805 00:46:55,400 --> 00:46:58,680 than 2%. It was even slightly less. 806 00:46:58,680 --> 00:47:06,120 So I think the adding the plate going one way was about 1.3, 807 00:47:06,480 --> 00:47:09,120 then adding the foam on top of that was .6. 808 00:47:09,840 --> 00:47:13,520 If you go the other way around, increasing the foam was about 809 00:47:13,520 --> 00:47:17,120 1.3, then adding the plate was only .6. 810 00:47:17,120 --> 00:47:21,560 So basically the individual effects were 1.3, but the 811 00:47:21,560 --> 00:47:24,120 summation of the effects was 1.9. 812 00:47:25,080 --> 00:47:28,840 And obviously it's hard to visualize in the podcast, but 813 00:47:28,840 --> 00:47:32,760 you can read the article when it's out or at least look at the 814 00:47:33,160 --> 00:47:36,920 the preprint right now. But basically, that was really 815 00:47:36,920 --> 00:47:40,120 interesting to us. And then going back to then show 816 00:47:40,120 --> 00:47:42,920 what is more important because both the foam and the plate sort 817 00:47:42,920 --> 00:47:45,920 of seem to have a similar benefit in this. 818 00:47:45,960 --> 00:47:49,400 This was the end of him Pro at that time. 819 00:47:51,640 --> 00:47:55,240 But then the one thing to consider though, as I am a big 820 00:47:55,240 --> 00:48:00,680 fan of the foam hypothesis was that adding a plate adds a 821 00:48:00,680 --> 00:48:04,720 little bit of weight. So you can only get that and, 822 00:48:05,040 --> 00:48:08,720 and going from an Eva foam to the to the P web-based foam 823 00:48:08,720 --> 00:48:13,440 actually reduces the weight. So if you take that into account 824 00:48:13,440 --> 00:48:16,240 because we balance the weight out in to control for that. 825 00:48:16,240 --> 00:48:18,840 But if we wouldn't have done that, you would have seen that 826 00:48:18,840 --> 00:48:21,440 the foam was slightly more beneficial than the plate. 827 00:48:23,880 --> 00:48:28,640 So again, putting all of those sort of things together sort of 828 00:48:28,640 --> 00:48:32,960 fits well with our hypothesis that the foam is is the main 829 00:48:32,960 --> 00:48:35,720 player. But obviously you can't ignore 830 00:48:35,720 --> 00:48:40,200 the fact that all of these shoes on the market have, well, what, 831 00:48:40,200 --> 00:48:45,560 what did I call it earlier, a rigid moderator or something, 832 00:48:45,560 --> 00:48:48,520 right? Either a plate or some rods or 833 00:48:48,520 --> 00:48:52,200 something in there. So it has to be there for a 834 00:48:52,200 --> 00:48:55,600 reason, right? So, and again, we, we also saw 835 00:48:55,600 --> 00:48:58,760 with this recent study that just the plate by itself could be up 836 00:48:58,760 --> 00:49:01,800 to 1%. So it's definitely doing 837 00:49:01,800 --> 00:49:07,800 something and and it seems to be slightly different between 838 00:49:07,800 --> 00:49:09,680 different models and brands and stuff. 839 00:49:10,440 --> 00:49:16,360 But overall it's to me, it seems that the foam is the major 840 00:49:16,640 --> 00:49:20,480 player. Then comes the plate and then 841 00:49:20,720 --> 00:49:23,320 sort of we start talking about geometry and there's sort of two 842 00:49:23,320 --> 00:49:26,960 things to the geometry. One is the overall stack height, 843 00:49:27,120 --> 00:49:30,280 thicker midsoles, and the other one is sort of the rocker 844 00:49:30,400 --> 00:49:33,280 towards the toe spring for a quicker roll off, right? 845 00:49:35,000 --> 00:49:40,040 So far there's been some people looking into and we have one 846 00:49:40,040 --> 00:49:45,960 study done on this too, looking at stack height per SE. 847 00:49:46,080 --> 00:49:50,360 So there was some idea that, well, if you just make the shoes 848 00:49:50,360 --> 00:49:54,840 so thicker, you're basically getting longer legs for free so 849 00:49:54,840 --> 00:49:58,040 you can run faster. Well, that's or for two. 850 00:49:58,040 --> 00:49:59,960 $150.00. Well, yeah, yes. 851 00:50:00,920 --> 00:50:03,960 Not for free at all. Yes, for. 300 in this case. 852 00:50:04,000 --> 00:50:09,080 Yeah, so, so, but even physically that's not how it 853 00:50:09,080 --> 00:50:11,680 works, right. So if we make people's legs 854 00:50:11,680 --> 00:50:18,280 longer and they could take a longer steps, you still have to 855 00:50:18,280 --> 00:50:22,680 sort of move your center of mass over your foot during stem. 856 00:50:22,680 --> 00:50:26,160 So basically the idea would be if you have a very long leg, 857 00:50:26,160 --> 00:50:29,800 then your glute muscles are going to go over hours because 858 00:50:29,960 --> 00:50:32,160 they need to work to get you over that. 859 00:50:33,680 --> 00:50:35,000 And that's kind of what we saw too. 860 00:50:35,000 --> 00:50:38,320 So we, we had sort of two versions of this study in our 861 00:50:38,320 --> 00:50:42,080 lab where one we purposely took a very firm phone so that it was 862 00:50:42,080 --> 00:50:45,560 really all about stack height. And we saw that running economy 863 00:50:45,560 --> 00:50:47,400 got worse with increasing stack height. 864 00:50:48,240 --> 00:50:50,480 And then we did it also in a fancy foam. 865 00:50:50,600 --> 00:50:53,920 And then we actually saw that it did get slightly better. 866 00:50:53,920 --> 00:50:58,440 So if you do have a bouncy foam, it might be a good thing, but 867 00:50:58,440 --> 00:51:01,320 then it's related to the pounds and not to the fact that you 868 00:51:01,320 --> 00:51:05,240 have longer legs. And then the other cool thing 869 00:51:05,240 --> 00:51:07,800 about that one is those differences were so small. 870 00:51:08,160 --> 00:51:11,760 And again, we did all this by controlling the shoe mass. 871 00:51:12,200 --> 00:51:16,960 And technically if you add more midsole foam, it's going to 872 00:51:16,960 --> 00:51:20,680 increase the weight. So that was going to counteract 873 00:51:20,680 --> 00:51:22,920 it again. And then that's why when you see 874 00:51:22,920 --> 00:51:27,600 those huge thickness Primax soles, they have these cut outs 875 00:51:27,640 --> 00:51:31,440 everywhere and trying to save mass everywhere to sort of 876 00:51:31,440 --> 00:51:34,000 counteract that. And that's, that might be an 877 00:51:34,000 --> 00:51:36,920 instability issue further down the road, which is probably more 878 00:51:36,920 --> 00:51:43,600 on your side than mine, but so that we did that study. 879 00:51:43,600 --> 00:51:47,240 And then Zac Barons, who's currently postdoc in my lab, did 880 00:51:47,680 --> 00:51:51,960 sort of similar study for his PhD work in Calgary working with 881 00:51:51,960 --> 00:51:56,840 ADI and, and basically found the same thing like extra stack 882 00:51:56,840 --> 00:51:59,880 height is not helpful. They didn't necessarily see that 883 00:51:59,880 --> 00:52:02,520 it was worse, but it was definitely not helpful. 884 00:52:03,320 --> 00:52:07,960 So just making those soles thicker by itself is not 885 00:52:07,960 --> 00:52:10,680 helpful. However, there's two benefits of 886 00:52:10,680 --> 00:52:13,200 having a well, three benefits of having a thicker shell. 887 00:52:13,360 --> 00:52:16,120 One is the extra balance, which I just mentioned. 888 00:52:16,480 --> 00:52:21,320 But talking about geometry purely, if you have a plate in 889 00:52:21,320 --> 00:52:24,520 there, it can be more curved because you have more room for 890 00:52:24,520 --> 00:52:27,160 it. And then the other thing is if 891 00:52:27,160 --> 00:52:31,040 you start higher, you can have this more aggressive rocker 892 00:52:31,040 --> 00:52:34,200 profile which might help you there. 893 00:52:34,600 --> 00:52:38,400 And some people are starting to publish on this. 894 00:52:38,400 --> 00:52:40,840 We have some work on this well as well. 895 00:52:41,560 --> 00:52:44,680 And it seems that we're now getting to the fact where there 896 00:52:44,960 --> 00:52:47,960 there probably is some advantage, but it's so small 897 00:52:47,960 --> 00:52:51,560 that within our measurements and we just talked half of the 898 00:52:51,600 --> 00:52:56,360 episode about the issues with that, we can't necessarily 899 00:52:56,360 --> 00:53:00,080 quantify it precisely. So we're, and that's basically 900 00:53:00,080 --> 00:53:02,720 in my view, like when something is less than a percent 901 00:53:02,720 --> 00:53:07,400 difference, you have to have either a lot of runners and a 902 00:53:07,400 --> 00:53:11,360 lot of patients to find it or for most studies we say like, 903 00:53:11,360 --> 00:53:15,160 well, we can't rule it out, but it's not an obvious difference. 904 00:53:15,160 --> 00:53:17,680 So this is where, where the sort of the rocker is sitting now 905 00:53:17,680 --> 00:53:23,000 with, with the toe spring and the roll off where there's there 906 00:53:23,000 --> 00:53:26,440 seems to be something going on by mechanically it makes sense. 907 00:53:26,960 --> 00:53:30,360 But if you look at running economy, that difference is not 908 00:53:30,360 --> 00:53:36,080 large enough to stand out statistically to be to be there. 909 00:53:36,400 --> 00:53:38,160 Which again, doesn't mean that it's not there. 910 00:53:38,240 --> 00:53:41,880 It's just too small to to stand out at the level where we 911 00:53:41,880 --> 00:53:45,480 measure it. I have about 3000 questions that 912 00:53:45,480 --> 00:53:48,840 I want to hear your thoughts on. I have two kind of parallel ones 913 00:53:48,840 --> 00:53:52,360 off of this regarding what you just talked about with varying 914 00:53:52,360 --> 00:53:55,880 stack heights as well as interactions of plates and 915 00:53:55,880 --> 00:53:58,400 different kinds of foams where it's not the sum of its parts, 916 00:53:58,400 --> 00:53:59,680 it's less than the sum of its parts. 917 00:53:59,680 --> 00:54:02,440 It and just to clarify, when I read that, well, when I read 918 00:54:02,440 --> 00:54:05,960 that study the, the one that's in preprint, it also is kind of 919 00:54:05,960 --> 00:54:09,560 like kind of mind spinning a little bit of just, hey, let's 920 00:54:09,800 --> 00:54:12,760 make sure that we're thinking about this cautiously and 921 00:54:12,880 --> 00:54:16,960 whatever. But you know, it sounds like 922 00:54:17,200 --> 00:54:22,760 adding the plate to the Piva or the the the soft bouncy foam did 923 00:54:22,760 --> 00:54:26,200 improve running economy to just the foam itself. 924 00:54:26,360 --> 00:54:28,880 It just wasn't as much as you expected it to be. 925 00:54:30,240 --> 00:54:32,280 It was it was less than the sum of its parts. 926 00:54:32,640 --> 00:54:39,080 But when it comes to the EBA and adding a plate, it also showed a 927 00:54:39,080 --> 00:54:41,560 greater improvement in the running economy with like the 928 00:54:41,560 --> 00:54:44,920 plate did more in the less fancy foam than it did in the fancy 929 00:54:44,920 --> 00:54:47,680 foam. And that's interesting because 930 00:54:47,680 --> 00:54:53,520 there's also some work from Victor Rodrigo, who was also in 931 00:54:53,520 --> 00:54:56,240 my lab twice for a couple of months. 932 00:54:56,640 --> 00:55:01,520 And I feel like he has another study where it was kind of 933 00:55:01,520 --> 00:55:04,560 opposite where the plate in the Eva didn't necessarily work. 934 00:55:04,560 --> 00:55:08,640 So to that that makes it very interesting. 935 00:55:09,360 --> 00:55:11,720 Yeah, OK. Well, that's that's interesting 936 00:55:11,720 --> 00:55:13,680 too and leads me into these questions. 937 00:55:14,000 --> 00:55:17,400 Like on the market right now, you're seeing a lot of people 938 00:55:17,400 --> 00:55:20,600 producing shoes that are being coined super trainers now. 939 00:55:20,840 --> 00:55:23,920 And so they might not be their lightest, most resilient foam, 940 00:55:23,920 --> 00:55:26,120 but it's usually very high stack height. 941 00:55:26,640 --> 00:55:29,120 They might have some sort of fancy foam, either the whole 942 00:55:29,120 --> 00:55:32,360 thing or part. What's your take on both these 943 00:55:32,360 --> 00:55:33,800 concept? They're just the concept of a 944 00:55:33,800 --> 00:55:39,400 super trainer as well as the idea of training in a plated 945 00:55:39,400 --> 00:55:41,720 shoe in general. Do you have perspectives on 946 00:55:41,720 --> 00:55:43,840 that? Yeah, excellent question. 947 00:55:43,840 --> 00:55:49,600 So I think just starting off with my personal approach to 948 00:55:49,600 --> 00:55:55,160 this is that right from the start, I've always been also a 949 00:55:55,160 --> 00:55:58,520 wear tester for many of these models with the different 950 00:55:58,520 --> 00:56:03,080 companies I work with. Which means that there have been 951 00:56:03,080 --> 00:56:07,440 periods where I was exclusively running in super shoes 952 00:56:07,600 --> 00:56:10,800 prototypes because they wanted to get as many miles on them as 953 00:56:10,800 --> 00:56:13,680 possible as soon as possible so that they could see where they 954 00:56:13,680 --> 00:56:15,880 were wearing out and what was happening and then they could 955 00:56:15,880 --> 00:56:20,520 update to the next model. So I personally have been 956 00:56:20,520 --> 00:56:25,120 running in super shows a lot and those were racing shoes that I 957 00:56:25,120 --> 00:56:30,440 would train in. I think that the the specific 958 00:56:30,440 --> 00:56:35,960 super trainers is interesting, which I'm not sure if that's 959 00:56:35,960 --> 00:56:41,480 just a marketing ploy to have people pay more or less, because 960 00:56:41,640 --> 00:56:46,040 if the alternative is to buy the Super racing shoe and train 961 00:56:46,040 --> 00:56:53,480 that, then it's actually less. And and that is super 962 00:56:53,480 --> 00:56:57,400 interesting by itself like and there's a lot of opinions on 963 00:56:57,400 --> 00:57:00,680 that. And again, personally, my 964 00:57:00,680 --> 00:57:05,160 experience has always been I just run in them all the time 965 00:57:05,160 --> 00:57:11,640 and it seems to work fine. But we're actually currently 966 00:57:12,880 --> 00:57:15,720 starting a study to look a little bit more into what's 967 00:57:15,720 --> 00:57:18,280 happening at levels of foot muscles in the different 968 00:57:18,640 --> 00:57:25,000 stiffness situations. But and then there's I think 969 00:57:25,000 --> 00:57:28,160 Justin Matisse has done his intervention studies for his 970 00:57:28,600 --> 00:57:32,360 master's work where people were assigned either a super shoe 971 00:57:32,360 --> 00:57:36,320 trainer or a flat trainer. But the flat might be a little 972 00:57:36,640 --> 00:57:39,960 too aggressive on the other side, where as an actual 973 00:57:39,960 --> 00:57:43,280 trainer, you want a kind of a trainer and not either a super 974 00:57:43,280 --> 00:57:47,480 shoe or a flat. But yeah, it's interesting and 975 00:57:47,480 --> 00:57:54,360 and it's sounds like I just again, this is the article in in 976 00:57:54,360 --> 00:57:58,840 MIT Technology Review that came out recently where journalists 977 00:57:58,840 --> 00:58:01,640 went to Kenya and talked to a lot of athletes there. 978 00:58:01,640 --> 00:58:07,600 And turns out that one of the coaches said that I think there 979 00:58:07,960 --> 00:58:11,680 is athletes are running about 60% of their miles in super 980 00:58:11,680 --> 00:58:18,400 shoes, which makes it even more of which makes it even more of a 981 00:58:18,520 --> 00:58:24,080 sort of economical equity question because the shoes are 982 00:58:24,080 --> 00:58:26,640 as expensive there. And some of the sponsors, 983 00:58:26,640 --> 00:58:31,640 athletes just either sell their shoes off second hand or 984 00:58:31,640 --> 00:58:33,880 something like that. But it it's getting more 985 00:58:33,880 --> 00:58:35,840 important, particularly the athletes hoping for this 986 00:58:35,840 --> 00:58:37,880 breakthrough. So that, that's a really 987 00:58:37,880 --> 00:58:41,280 interesting read actually. But again, that's also pointing 988 00:58:41,280 --> 00:58:45,920 out that those elites are doing it and and sort of journalists 989 00:58:45,920 --> 00:58:49,520 went there when Kipton was still alive. 990 00:58:49,520 --> 00:58:52,440 So he started to spin the story around that and then he passed 991 00:58:52,440 --> 00:58:54,320 away. But there's also a lot of talk 992 00:58:54,320 --> 00:58:58,200 that Kipton, as most people know, was running such high 993 00:58:58,200 --> 00:59:00,560 volumes. And some people are saying that 994 00:59:00,560 --> 00:59:03,880 that's because of the fact that he was running all of those in 995 00:59:03,880 --> 00:59:07,920 in bouncy shoes, which he probably might not have been 996 00:59:07,920 --> 00:59:10,640 able to do that if he was doing this all bear footed, right? 997 00:59:12,000 --> 00:59:16,440 But then there's a whole Born to run argument on the other side 998 00:59:17,120 --> 00:59:20,040 that says, like, oh, the East African runners are so good 999 00:59:20,040 --> 00:59:24,600 because they run on barefoot growing up and things like that. 1000 00:59:24,600 --> 00:59:30,280 So I don't necessarily know right now which is better and if 1001 00:59:30,280 --> 00:59:31,760 there is something that's better for everyone. 1002 00:59:31,760 --> 00:59:34,800 It comes back to Matt's earlier comment about it's going to vary 1003 00:59:34,800 --> 00:59:40,040 from individual to individual and, and then for trainers, it 1004 00:59:40,040 --> 00:59:41,880 really comes down to what you want to get out of it. 1005 00:59:41,880 --> 00:59:46,440 Like I ran a 50K trail race yesterday and today I went on a, 1006 00:59:46,760 --> 00:59:51,240 on a recovery run in my most bouncy Max tech height shoe that 1007 00:59:51,240 --> 00:59:56,520 I have and it felt great. But if I was going to do a tempo 1008 00:59:56,520 --> 00:59:59,080 workout that she would have been way too slow, right? 1009 00:59:59,080 --> 01:00:02,680 So it's really depends on what you want to get out of this shoe 1010 01:00:02,680 --> 01:00:06,480 and how much money you have to buy racing flat racing super 1011 01:00:06,480 --> 01:00:09,200 shoes all the time. And how fast you want to wear 1012 01:00:09,200 --> 01:00:12,920 those out. So, but there's something to 1013 01:00:12,920 --> 01:00:15,720 specificity. I want to do say that like I 1014 01:00:15,720 --> 01:00:19,760 feel like, well, there's two things I want to say. 1015 01:00:19,760 --> 01:00:23,160 One is I don't necessarily believe the argument that if you 1016 01:00:23,160 --> 01:00:26,840 run in in stiff shoes or super shoes, that your foot muscles 1017 01:00:26,840 --> 01:00:29,280 are going to get a lot weaker. I mean, you're not sitting on 1018 01:00:29,280 --> 01:00:31,400 the couch, you're still out there running. 1019 01:00:32,880 --> 01:00:35,640 And but there's definitely the the specificity of usage. 1020 01:00:35,680 --> 01:00:38,200 And you would say, oh, you might use these muscles slightly less 1021 01:00:38,200 --> 01:00:40,680 than you would have if you would have worn other shoes. 1022 01:00:40,680 --> 01:00:43,640 So maybe relatively. And then can we scientifically 1023 01:00:43,640 --> 01:00:48,160 even measure that? But yeah, but then again, also 1024 01:00:48,160 --> 01:00:50,520 the specificity comes back to if you're going to be racing in 1025 01:00:50,520 --> 01:00:53,960 these shoes, you, you definitely want to have been training in 1026 01:00:53,960 --> 01:00:58,320 them to some extent that it's not a new thing for you on race 1027 01:00:58,320 --> 01:01:01,080 day. So this is a hypothesis and I 1028 01:01:01,080 --> 01:01:04,480 have no basis for this, but this has been a thought that I've 1029 01:01:04,480 --> 01:01:05,720 had. I've seen this because yes, 1030 01:01:05,720 --> 01:01:10,680 these shoes improve economy. Is it possible that it they, 1031 01:01:10,680 --> 01:01:13,840 they essentially allow, as you mentioned, it may, might allow 1032 01:01:13,840 --> 01:01:17,000 you to train at harder levels. So if you trained, let's say 1033 01:01:17,000 --> 01:01:19,400 your normal run, let's you're just someone running 100 1034 01:01:19,400 --> 01:01:21,240 kilometers a week. For example, if you run 100 1035 01:01:21,240 --> 01:01:26,160 kilometers a week in a traditional racing shoe, a flat 1036 01:01:26,160 --> 01:01:29,480 or a trainer, titles are very different compared to a super 1037 01:01:29,480 --> 01:01:31,920 shoe, right? That that's not going to give 1038 01:01:31,920 --> 01:01:33,280 you that maybe much of a difference. 1039 01:01:33,280 --> 01:01:37,680 However, what the Super shoes allow you to do is do 160 1040 01:01:37,680 --> 01:01:41,400 kilometers, for example. You can do that, but that's what 1041 01:01:41,400 --> 01:01:44,320 it takes now to get that same stimulus based on Justin's study 1042 01:01:44,320 --> 01:01:48,680 is that yes, you might not have as much stimulus from the 1043 01:01:48,680 --> 01:01:51,560 workouts, but what the Super shoes allow you to do is they do 1044 01:01:51,560 --> 01:01:54,800 allow you to do more. So you might be able to go the 1045 01:01:54,800 --> 01:01:57,120 distance rather, I'm not going to say speed, but allow you to 1046 01:01:57,120 --> 01:01:59,760 get more training in, but you actually have to put that 1047 01:01:59,760 --> 01:02:01,800 greater amount of training in to get the effect. 1048 01:02:02,400 --> 01:02:03,960 Is that fair or do you think that's a complete 1049 01:02:03,960 --> 01:02:07,080 misunderstanding? I, I, I do think that it's a 1050 01:02:07,080 --> 01:02:10,200 very good point. And I think that's sort of my my 1051 01:02:10,200 --> 01:02:12,880 counter argument to sort of the weak, the weak foot muscles too 1052 01:02:12,880 --> 01:02:17,160 is like, yeah, I don't get I could have run 20 miles in my 1053 01:02:17,160 --> 01:02:20,640 traditional shoe, but now I ran 24 in my super shoe. 1054 01:02:20,920 --> 01:02:22,760 Am I getting weaker foot muscles now? 1055 01:02:22,760 --> 01:02:28,200 I don't think so. But then again, whether what you 1056 01:02:28,200 --> 01:02:32,760 need to get the stimulus. And that's also the thing that 1057 01:02:33,040 --> 01:02:35,720 with recovery, recovery modalities that comes up all the 1058 01:02:35,720 --> 01:02:38,120 time too, right? You, you don't want to have the 1059 01:02:38,120 --> 01:02:41,640 best recovery modality that blunts away all the the training 1060 01:02:41,640 --> 01:02:43,800 stimulus because then why did you even train? 1061 01:02:45,160 --> 01:02:49,320 And for shoes, we're sort of seeing a a similar thing and 1062 01:02:50,560 --> 01:02:55,760 whether you really need that extra volume to get the benefits 1063 01:02:55,760 --> 01:02:59,040 or whether it's more something that allows you to put in the 1064 01:02:59,040 --> 01:03:02,120 harder workout and that gives you the benefits. 1065 01:03:02,120 --> 01:03:04,880 I think that's sort of kind of vary again, between people. 1066 01:03:05,200 --> 01:03:10,000 And that was sort of the the, yeah, the story about the 1067 01:03:10,000 --> 01:03:13,120 coaches from from Kenya too, that the athletes are doing this 1068 01:03:13,320 --> 01:03:15,960 so they can run more, they recover quicker. 1069 01:03:17,040 --> 01:03:20,360 There's still very little scientific data on that, but I 1070 01:03:20,360 --> 01:03:22,800 think that's also something that's really hard to measure. 1071 01:03:22,800 --> 01:03:29,480 And I think the consensus is from a it makes a lot of sense. 1072 01:03:29,480 --> 01:03:33,520 And two anecdotes from everybody just seem to confirm this. 1073 01:03:34,840 --> 01:03:39,040 But you know it, it's intriguing to see whether it does change 1074 01:03:39,040 --> 01:03:43,000 the stimulus in a little bit and that you're not getting as much 1075 01:03:43,000 --> 01:03:45,360 out of it if you just keep doing the exact same thing. 1076 01:03:46,160 --> 01:03:48,120 But it also allows you to do more. 1077 01:03:48,120 --> 01:03:51,880 So the problem for ultra runs like me is that then you're just 1078 01:03:51,880 --> 01:03:54,800 always running. You can't do anything else. 1079 01:03:57,440 --> 01:04:00,880 Can you tell the the people who listen to this podcast are 1080 01:04:00,880 --> 01:04:03,720 probably asking what did he run his 50K in? 1081 01:04:04,320 --> 01:04:07,120 Can you answer that question or are you were you running in 1082 01:04:07,120 --> 01:04:10,720 something that can't be talked? About no, no, this was a local 1083 01:04:11,520 --> 01:04:15,600 50K trail race. I, I am happy to share my time 1084 01:04:15,600 --> 01:04:18,160 that I ran yesterday, but I also want to share then what I did a 1085 01:04:18,160 --> 01:04:21,720 couple of weeks ago. So yes, yesterday I ran it. 1086 01:04:22,240 --> 01:04:26,760 It was it was a little over 50 Ki was probably 32 1/2 miles 1087 01:04:27,680 --> 01:04:30,840 with about 5000 feet. And I ran it in five hours and 1088 01:04:30,840 --> 01:04:35,080 10 minutes. It was good enough to win it. 1089 01:04:35,920 --> 01:04:40,680 But June has June has been a pretty heavy racing month for 1090 01:04:40,680 --> 01:04:44,120 me. And throughout the month I've 1091 01:04:44,120 --> 01:04:46,960 been getting slower and slower, but I also have been running 1092 01:04:46,960 --> 01:04:50,760 harder and harder courses. It's that's the thing with the 1093 01:04:50,840 --> 01:04:53,360 ultra trail style. It's hard to compare A to B, 1094 01:04:53,360 --> 01:04:56,040 but. And what shoes were you wearing? 1095 01:04:56,800 --> 01:05:04,080 Yesterday I ran the the 50K and the other races too last week, 1096 01:05:05,400 --> 01:05:15,200 which is a Puma deviant elite one with a trail outsole on it 1097 01:05:16,520 --> 01:05:20,680 custom made for me back then by somebody at fibrum. 1098 01:05:22,080 --> 01:05:26,320 But it's funny because I was recently talking to people at 1099 01:05:26,320 --> 01:05:28,600 Puma and they were like, wow, you still have that deviator 1100 01:05:28,600 --> 01:05:30,520 that only want to I kind of want to see it. 1101 01:05:30,520 --> 01:05:34,240 So I pulled it out and we found out that the plate is, is, is 1102 01:05:34,240 --> 01:05:38,840 long cracked and gone. And, and it's like, because you 1103 01:05:38,840 --> 01:05:42,600 can even see cracks in the in the in the fever outsole and 1104 01:05:42,600 --> 01:05:46,560 stuff. But it's, it's still my favorite 1105 01:05:47,120 --> 01:05:50,240 trail ultra shoe because it's, it's, it's it's it has all the 1106 01:05:50,240 --> 01:05:53,920 nice properties to it. And yeah, it's, it's, it's not, 1107 01:05:54,600 --> 01:05:57,640 I I still feel like the the deviant League One from Puma was 1108 01:05:57,640 --> 01:05:59,960 like the most democratic super shoe. 1109 01:05:59,960 --> 01:06:05,160 That was, it was very stable. It wasn't too aggressive, so 1110 01:06:05,160 --> 01:06:08,560 that's why I like it for for the longer stuff, but apparently 1111 01:06:09,000 --> 01:06:11,520 Puma is working on something like this that's coming out. 1112 01:06:12,320 --> 01:06:16,040 It's in the pipeline so I hope to switch to that sometime soon 1113 01:06:16,040 --> 01:06:18,520 rather than. It's funny, I well. 1114 01:06:18,840 --> 01:06:20,640 Before the shoot. Disintegrates off your foot, 1115 01:06:20,720 --> 01:06:24,400 yeah. Todd Falker was running the Ice 1116 01:06:24,400 --> 01:06:26,520 Age 50 and I was down there crewing a friend. 1117 01:06:26,520 --> 01:06:29,560 So I ran with him for maybe half mile just to say hi. 1118 01:06:29,800 --> 01:06:32,280 And he had a custom pair of those on his feet. 1119 01:06:32,280 --> 01:06:33,840 So, you know, I was like, that'd be awesome. 1120 01:06:33,840 --> 01:06:38,040 So all right, so I want to wrap things up, but I have one final 1121 01:06:38,040 --> 01:06:41,040 question for you. It's not necessarily a short 1122 01:06:41,200 --> 01:06:43,720 question, but you can answer it as briefly as you want to. 1123 01:06:44,160 --> 01:06:47,680 And it basically is about what you've alluded to about some 1124 01:06:47,680 --> 01:06:50,880 people being responders and some people not being responders. 1125 01:06:51,080 --> 01:06:54,280 I also want to pair into a lot of companies producing two types 1126 01:06:54,280 --> 01:06:57,080 of super shoes. So like Puma has the fast R and 1127 01:06:57,080 --> 01:07:00,120 they have the Deviate Nitro Elite A6 will have the meta 1128 01:07:00,120 --> 01:07:04,280 speed edge and sky. What are some of the things that 1129 01:07:04,280 --> 01:07:07,360 you think are most responsible for responders versus non 1130 01:07:07,360 --> 01:07:09,360 responders? And how much does the different 1131 01:07:09,440 --> 01:07:12,360 type of rocker geometry play into that? 1132 01:07:12,520 --> 01:07:16,160 Yeah, that's, that's sort of the, the big question at the 1133 01:07:16,160 --> 01:07:21,200 moment. I, I think so I think we can say 1134 01:07:21,200 --> 01:07:22,520 and we have seen that too, right. 1135 01:07:22,520 --> 01:07:25,480 So if you carefully measure running economy, you still will 1136 01:07:25,480 --> 01:07:27,960 see that some people have a bigger benefit than others. 1137 01:07:28,160 --> 01:07:30,920 So let's focus on the first half of the episode. 1138 01:07:30,920 --> 01:07:33,880 We we have that figured out. So we're actually looking at 1139 01:07:33,880 --> 01:07:36,400 real responses and a variation in those. 1140 01:07:36,880 --> 01:07:41,200 And then yeah, there is, there's got to be variability. 1141 01:07:41,200 --> 01:07:49,160 And I think that there is my big, big picture, there's like 1142 01:07:49,280 --> 01:07:51,200 20 variables that can go into this. 1143 01:07:51,200 --> 01:07:54,600 But obviously one of the biggest things is sort of the ground 1144 01:07:54,600 --> 01:07:58,920 reaction forces, which is sort of determined by your cadence, 1145 01:07:58,920 --> 01:08:02,800 your speed and your body weight and your contact time. 1146 01:08:02,800 --> 01:08:05,800 So that's already adding up all these things. 1147 01:08:05,800 --> 01:08:12,400 But what we do seem to see is like in some of our recent spike 1148 01:08:13,200 --> 01:08:19,520 research too, is that the right way to put it is like sort of 1149 01:08:19,520 --> 01:08:22,960 like we saw that, and I'm not saying this is a sex effect, it 1150 01:08:22,960 --> 01:08:26,960 might be a body weight effect. So we saw that tiny women or 1151 01:08:26,960 --> 01:08:30,080 women that were generally tiny as compared to the men group, 1152 01:08:30,840 --> 01:08:37,279 they for example, had they had similar improvements in a spike 1153 01:08:37,279 --> 01:08:42,399 with a fancy foam and a plate fancy foam alone and the spike 1154 01:08:42,399 --> 01:08:46,560 with the fancy foam and the plate versus the heavier men who 1155 01:08:46,560 --> 01:08:50,240 also ran faster and on efforts were heavier. 1156 01:08:51,640 --> 01:08:55,560 There you saw the difference like they had an an additional 1157 01:08:55,560 --> 01:08:58,240 benefit of the plate or or the other way around. 1158 01:08:58,240 --> 01:09:00,640 They had less of a benefit from just the foam. 1159 01:09:01,720 --> 01:09:05,120 And there we sort of see again, it makes sense. 1160 01:09:05,120 --> 01:09:08,920 If you're heavier, you run faster, you might put a little 1161 01:09:08,920 --> 01:09:13,680 more force into that shoe and you might not get it all out of 1162 01:09:13,680 --> 01:09:16,640 there, particularly with the spikes with the limited stack 1163 01:09:16,640 --> 01:09:20,319 height. So thinking along those lines 1164 01:09:21,560 --> 01:09:25,080 that that might explain some of these things, but then it's much 1165 01:09:25,120 --> 01:09:27,560 more complicated than just the foam because we just talked 1166 01:09:27,560 --> 01:09:30,960 about the plate. And then is it about the 1167 01:09:30,960 --> 01:09:33,600 geometry of the plate? Is it about the calf muscle 1168 01:09:33,600 --> 01:09:37,479 strength? Is it, I think that the ASIC 1169 01:09:37,479 --> 01:09:42,960 story is around the the, the cadence runners that and they 1170 01:09:42,960 --> 01:09:45,040 have some data on that to support that. 1171 01:09:46,560 --> 01:09:50,600 And then again from Puma 2, we have been exploring who are 1172 01:09:50,600 --> 01:09:54,120 responding better in the DVD Elite and in the fast are. 1173 01:09:54,480 --> 01:10:01,560 And again, it's not always obvious, but there is again 1174 01:10:01,560 --> 01:10:04,920 something like, yeah, Molly Seidel might run slightly 1175 01:10:04,920 --> 01:10:09,400 different than I do, but then she's running different than me 1176 01:10:09,400 --> 01:10:15,320 in very different many ways. And also she is probably a lot 1177 01:10:15,320 --> 01:10:18,160 less heavy than I am and, and things like that. 1178 01:10:18,160 --> 01:10:22,240 So, but she's running slightly faster than I am. 1179 01:10:22,240 --> 01:10:24,480 So maybe that counteracts. So again, so there's, there's a 1180 01:10:24,480 --> 01:10:27,880 lot of things that go into this. So scientifically, I don't have 1181 01:10:27,880 --> 01:10:31,600 an answer. I think just personally 1182 01:10:31,600 --> 01:10:35,080 speculating. I think that and again, it's 1183 01:10:35,080 --> 01:10:36,520 going to depend on a model too, right? 1184 01:10:36,520 --> 01:10:40,800 So some people might be perfect responder in the DVL elite and 1185 01:10:40,800 --> 01:10:44,400 not in the fast are what is it then there? 1186 01:10:45,600 --> 01:10:52,240 But I do feel like as a field, we hopefully can find this out 1187 01:10:52,240 --> 01:10:54,920 sometime soon. But it's tricky because we can't 1188 01:10:54,920 --> 01:10:58,440 just look at it across 20 people. 1189 01:10:58,440 --> 01:11:01,120 Because if you're going to compare 20 people, they're going 1190 01:11:01,120 --> 01:11:04,560 to have slightly different paces and body sizes and calf muscle 1191 01:11:04,560 --> 01:11:07,960 strengths and foot strengths. And maybe the toe is relatively 1192 01:11:07,960 --> 01:11:11,000 longer to the foot and maybe the plate is not bending right under 1193 01:11:11,000 --> 01:11:15,520 the MTP joint. So, so that's, it's not an easy 1194 01:11:15,520 --> 01:11:21,680 task, but I think with some clever experimental design we 1195 01:11:21,680 --> 01:11:23,480 might start to find some of these things out. 1196 01:11:23,480 --> 01:11:26,040 And there already have been some studies that show that speed is 1197 01:11:26,040 --> 01:11:27,680 important. And again, biomechanically that 1198 01:11:27,680 --> 01:11:33,240 makes a lot of sense. So hopefully in the future we 1199 01:11:33,240 --> 01:11:38,320 can go to the store and, and do some tests and assessments and 1200 01:11:38,320 --> 01:11:41,560 then say, OK, well, you need this much foam of this stiffness 1201 01:11:41,560 --> 01:11:44,480 with this plate with the curvature there with this plate 1202 01:11:44,480 --> 01:11:47,640 stiffness and that's going to be the shoe for you. 1203 01:11:47,640 --> 01:11:52,040 But I think our field still needs to do a lot of work to 1204 01:11:52,040 --> 01:11:55,400 actually make those inferences. But I think it's possible and 1205 01:11:55,520 --> 01:11:59,520 we'd be super excited if we all just get the shoe that's optimal 1206 01:11:59,520 --> 01:12:05,280 for ourselves and have that made and 3D printed and or delivered 1207 01:12:05,280 --> 01:12:10,000 by drone either way. Yeah, amazing. 1208 01:12:10,960 --> 01:12:13,440 Well, we are going to wrap things up here. 1209 01:12:13,760 --> 01:12:17,480 We have left a lot of questions on the table that maybe someday 1210 01:12:17,480 --> 01:12:19,880 we'll be able to ask you at an at a future time. 1211 01:12:19,880 --> 01:12:22,560 I know you're a busy person. You're always helping us 1212 01:12:22,560 --> 01:12:25,800 understand how we interact with these shoes more. 1213 01:12:25,800 --> 01:12:28,440 So thank you for all of your professional work that you're 1214 01:12:28,440 --> 01:12:30,120 doing. And I also love how you're 1215 01:12:30,400 --> 01:12:33,320 willing and able to differentiate what the science 1216 01:12:33,320 --> 01:12:36,520 tells us and what some of your intuitions are and just that 1217 01:12:36,520 --> 01:12:38,240 that was super fun for us to hear. 1218 01:12:38,240 --> 01:12:42,200 So if people are wanting to look more into your research or just 1219 01:12:42,200 --> 01:12:45,680 follow you a little bit more, are there best ways for people 1220 01:12:45,680 --> 01:12:51,000 to find you online? Yeah, so I did drop Axe when it 1221 01:12:51,000 --> 01:12:53,320 became Axe. So I think the best place to 1222 01:12:53,320 --> 01:12:59,240 find me now would just be to go to my website and there I should 1223 01:12:59,440 --> 01:13:04,640 probably update it maybe even before this airs to to be a 1224 01:13:04,640 --> 01:13:09,800 little more up to date. But the other way to to and. 1225 01:13:10,080 --> 01:13:11,840 That's just Walter hookcommer.com. 1226 01:13:11,840 --> 01:13:12,920 Exactly. Yes, yes. 1227 01:13:12,920 --> 01:13:15,200 And which is not straightforward because that's hard to spell, 1228 01:13:15,200 --> 01:13:20,080 but and I'm on Strava. We can put it in the show notes. 1229 01:13:20,520 --> 01:13:24,760 Oh Strava, I got to find you on. I put some some lab tests 1230 01:13:24,760 --> 01:13:28,920 insights in there. And then yeah, I think the 1231 01:13:28,920 --> 01:13:32,080 Google Scholar profile is usually good because nowadays 1232 01:13:32,160 --> 01:13:35,600 preprints are getting up there pretty soon, early on too. 1233 01:13:35,680 --> 01:13:40,800 And that's just a nice way for our scientists to quickly start 1234 01:13:40,800 --> 01:13:43,480 sharing findings, even though they're not fully gone through 1235 01:13:43,480 --> 01:13:47,560 Peer with you. But yeah, between my website at 1236 01:13:47,560 --> 01:13:51,600 botcomer.com and my Google Scholar, and if you want, even 1237 01:13:51,600 --> 01:13:55,040 on Strava, that's the best ways to find me. 1238 01:13:55,520 --> 01:13:57,560 Fantastic. Well, thank you again for your 1239 01:13:57,560 --> 01:13:59,480 time. We know it's a late Sunday night 1240 01:13:59,480 --> 01:14:01,960 and we just appreciate all of your insights and the things 1241 01:14:01,960 --> 01:14:04,600 that you shared with us. And if you are following us at 1242 01:14:04,600 --> 01:14:08,600 Docs of Running, as always, you can find what we're up to and 1243 01:14:08,600 --> 01:14:10,960 we'll have this podcast posted on our website, 1244 01:14:10,960 --> 01:14:13,840 docsofrunning.com. You can see us on social at that 1245 01:14:13,840 --> 01:14:15,960 handle as well. Have a good night everybody.