144. Minimalist Shoes, Running Mechanics & Barefoot Training | Irene Davis, PhD, PT

Welcome to Medicine Redefined, a podcast focusing on helping you reclaim ownership of your health. I'm Dr. Darsha, and I'm Dr. Altamasharaja, where your hosts, hair to challenge conventional practices and uncover the stories behind pioneers shaping the future of medicine. Our conversations not only focus on the individual level to dissect common practices for health optimization, but also zoom out to enhance systemic change. Join us as we look to break the status quo, move the needle forward, and put the help back in healthcare. Our guest today is Dr. Irene Davis. Dr. Davis is a professor in the School of Physical Therapy and Rehabilitation Science at the University of South Florida. Prior to this, she was the founding director of the Spalding National Running Center in the Department of Physical Medicine Rehabilitation at Harvard Medical School. Dr. Davis received her Bachelor of Science in Exercise Science from the University of Massachusetts and Physical Therapy from the University of Florida. She earned her Master's in Biomechanics from the University of Virginia and her PhD from Penn State University. She is a professor emeritus in Physical Therapy at the University of Delaware, where she served on the faculty for over 20 years. Her research is focused on the relationship between lower extremity structure, mechanics, and injury. Her research also extends to the development of interventions to ultra-faulty mechanics through gate retraining. Dr. Davis has been studying the use of wearable sensors in both the evaluation and treatment of injured runners. Her interest also include the effect of minimalist footwear, mechanics, and injury, and that is what the majority of our conversation today is centered around. Barefoot training has been quite the craze over the past decade and appears to be promising in the right context. I personally was a huge fan, but veered away for a while because of the injuries I was seeing in practice from people improperly incorporating barefoot training into their exercise program. Well, lucky for you, Dr. Davis provides valuable insight on how and why to do that without getting a fast-track ticket to one of our clinics. Other things that you'll also learn by the end of this conversation include Dr. Davis's journey into PT and how she developed a passion into minimalist footwear and training. We talk about foot anatomy and the importance of spending time, training, and addressing the foot core, which is probably not something we spend enough time addressing, and maybe just as important as a lumbopelve core, especially if you're a runner or athlete of any sort. We discuss different footstrike patterns and force distribution. We also cover various foot types and shoe types such as motion control, stability, etc. And then we discuss the role of minimalist footwear training and how it applies to life outside the athletic endeavors while discussing some clinical relevance for my health care professionals as well. If all this sounds a little bit intimidating to you, don't worry because Dr. Davis does an exceptional job breaking down the concepts into simple terms with some visual aids to make them more digestible. In Morgan News, she has agreed to come back for a part two, so you have that to look forward as well. Now with that further delay, please enjoy this highly educational discussion with Dr. Irene Davis. Hey everyone, real quick, we are closer rolling out a newsletter containing high yield notes for our guests and tips and tricks from us. We want to put the health back in health care and want to help you do the same by giving you the necessary information to live your best lives and provide value to those around you. Go ahead to medicineredefine.com where you can input your email and stay up to date. All right, thanks. Time for the episode. All right, Dr. Irene Davis, thanks so much for coming on to our podcast. I'm super happy we're making this happen. Thanks. It's great to be here, looking forward to it. Yeah, absolutely. So what we're going to be talking about, barefoot, minimalist training, shoes, footwear, foot anatomy, kinetic chain, just a bunch that we're really going to delve into here, I have been really passionate about this and actually just recently presented my Grand Rounds during my last year of residency here at Penn State. So right now, I feel like a kid waking up on Halloween day, getting ready to go out and get all that candy and I know I'm going to learn so much from you here. But I think it's important for the audience to understand how you ended up as learning and making this your specialty, your physical therapist by training and I know our footprints have probably crossed that at some point you were at Penn State. I think you're also in Hufflestown, which is where our rehab hospital it is. So tell us a little bit about your journey. What got you interested in physical therapy and specifically barefoot minimalist shoes? It's an interesting story and you know, it's funny, your career is this dynamic entity. They start out in a direction you never know where you're going to end up and it's often circuitous and mine was. But when I started off really at the University of Massachusetts, it's an exercise science. But before that, I really wanted to be an FBI agent. I always love to put this in part of my story because you know, I used to have these dreams about getting caught and escaping and catching, you know, the magic lipstick and agent 99 and all of that. And I wanted to be an FBI agent. And I wrote Jay Guhu for a letter and I actually have that letter that he signed in my safe. He basically said that, you know, at the age I was 15 at the time I wanted to do a summer internship and he said, women aren't allowed in the FBI. You could be an administrative assistant. And that just like dashed my hopes and I didn't know what I wanted to do. And I literally didn't go to college right away, took a year off. I want a motorcycle, I drove around that he's coast and rode with a motorcycle gang and had kind of an interesting sort of gap year before gap was really popular. And then I went to the University of Massachusetts and I was really interested in sort of exercise and human body. And so actually I science, he makes sense. But I then really started to have this desire to do something in health. I had a cousin who had a spinal cord injury, C5 level. And you know, I saw him working with a physical therapist and that's really what got me interested. So I did my degree down at the University of Florida. It was an accelerated program at the time. So I did another bachelor in 15 months. So I bachelor in exercise science and I did a bachelor's in physical therapy. And then I started practicing as a physical therapist. But I knew, I think, you know, when people, when you know someone's going to go on to a PhD, they're people who are always questioning and trying to figure things out. And I really loved doing that. It's kind of why I wanted to be an FBI agent. It's kind of how it ties in. So I really thought I need to, I want to go back to school. So I did work for three years in a rehab setting and working with people with spinal cord injuries. And I actually loved it. I loved that work. But I knew I wanted to go on. So I did my masters in biomechanics at UVA. And then I went to Penn State University where it was really the pioneer in the area of running mechanics, Dr. Peter Kavanaugh at Penn State. And so I went there and he was a biomechanist but didn't have the clinical background. I wanted to sort of marry the clinical with the science. And I love that space that I've been in my whole career is I, I've one foot in the science and one foot in the clinical and you know, it helps me because things are, I can make things relevant. I can make the research relevant. And that was really important to me. So I started out, after I did my PhD, I, my first job was at the University of Delaware. And interestingly enough, I was actually the person because someone I had worked with at one of the PhD students was into foot orthotics and all of that and got me interested in it. And so I actually started, you know, kind of teaching foot orthotics and motion control and cushion shoes. And I was actually the go to person in the faculty department at the University of Delaware and the PT faculty to like make the orthotics teach it in the classroom. So I come from that, which is very, it's like 180 degrees, right? So how do you get from that to where I am now? And it's really through evolution of thought. And you know, the message I try to tell people, you try to impart to young people is that you need to keep your mind open, that you evolve in your relationships. You evolve as a person and you evolve in your science. And you have to sometimes be able to let go of your dogma and I had some clinical dogma. I was hanging on to with, you know, the fact that I thought orthotics were really the end I'll be all for all problems to maybe opening my mind up. And the way it happened, it wasn't all of a sudden. It happened when I started out looking at different foot strike patterns, your foot strikeers versus for foot strikeers because my advisor, Peter Kavanaugh, had noticed, just noticed who really was, didn't make a big deal of it, that people who land on the ball of their feet tend to have no impact peak. And those are sort of the, you know, the outliers, they're not the norm. I now think it is really what the norm should be, but, and he just teach kind of notices. So I decided to take that a little farther when I, one of my first studies was to look at differences between a foot strike or some for foot strike. So we found it indeed, even when you look at a big large group of them, that's what you see a very big difference in their mechanics and especially during the impact phase, right? Now at the same time, the very first barefoot running paper came out at about that same time I was studying that. And they showed that barefoot runners, Agnes and the author was duet. And he showed that barefoot runners actually land on the ball of their foot. So then I started thinking, okay, barefoot runners, run on the ball of their foot, we started out barefoot, for foot striking, doesn't have an impact, these impacts have been shown by other researchers like Raiden and others that impacts can cause damage to bone. And so I started to put it together and I thought, hmm, you know, maybe, maybe for foot striking is really more natural than rear foot striking. I started to go down that path. And during that period, Chris McDougal, who was living in Pennsylvania in the Hummelstown, sort of neck of the woods, Lancaster, I think is where he was living, he was a journalist, a freelance journalist for The New York Times. And it came down to do a story about strike patterns and, you know, just barefoot versus shoes and all of that. And that really kind of started a very, a relationship we still have today. And basically, he incorporated some of the things that we had done when he came down to the clinic for his article and the book board to run. And so I was talking to him about, yeah, I was running, but I was, you know, I actually hadn't run. I ran in college when I was at UMass. I hadn't run because I started getting injured, don't even remember what was. I just know that it hurt when I ran, it didn't hurt when I didn't run. So I thought, okay, running's not for me, right? So I didn't run for a long time. And I said, you know, I want to try this. So, you know, what should I do? Should I, you know, should I get those funny toe shoes? I mean, how should I do this? And he said, honey, you got to start out barefoot. He said, and I said, but I really don't want to get calluses because my feet, you know, I'm girl and I paint my toenails and he goes, the world is your pumice stone, you know, it'll, you won't get big calluses and you need to feel the ground at least to learn how to do this correctly. So he came and did some barefoot running clinics at the University of Delaware with this. And that's kind of where I started to, to kind of run both barefoot and with minimal shoes. And it started my, you know, the really another phase of my research trying to understand what are the differences, right? And what are the differences in injuries? And, you know, I guess I'm at the point now in my career where I want to know, how do we get this more universal? Like, it's a big, you know, it's a big deal because we've got some very powerful shoe companies who have very deep pockets who want to adapt and to the, you know, add, add, add, add, add to the body. So the body has to do less, less and less in a sense, right? The minute you start adding cushioning, the body doesn't have to cushion you add support, the body doesn't have to support. And so that's kind of where I am now is I'm really trying to brainstorm how we get this message more universal. And I'll stop there because I've been talking a lot and I'm sure you have some questions. So no, I mean, that's an awesome story. And I mean, you've had a lengthy journey when where you weaved in and out. And I really appreciate kind of what you talked about dogma. And I think for those listening, I think most people won't know what orthotics are, but essentially it's an assistive device. And I think a lot of people recognize it as foot inserts, right? So whether it's for quote unquote, low arches versus high arches, we'll get into all of that stuff. I, you know, we were going to ask you why you think beer for running is making kind of a comeback, but you already alluded to that. I suppose this is might be a good place to maybe just talk about the just overarching high level anatomy of the foot, right? I mean, particularly maybe we could start about talking about different types of arches because that's really for most people entry point when they go to a running store and they'll maybe walk on some, you know, treadmill type, which is looking at pressure patterns, quote unquote, and maybe if they're lucky, they'll do like a true gate assessment or wash them run or, you know, I'm not really sure what the experience is of those people selling that, whether they're a salesman versus kinesiologist, but they might say, okay, motion control versus those things that you kind of talked about. So maybe if you could start there and tell people like what the difference between low arches, high arches is and why that matters, like why are people recommending you need a more motion control shoe versus a different type of shoe? And why do we care about that? So I'm going to answer your question by saying it doesn't matter. I don't think it matters. I think we do all have a wide, if you look at a population of a population, you're going to see a variety of archites across that population, just like you're going to have a see a variety of body types and heights and weights and, you know, even anthropometric ratios of the femurs to tibia, we're all different. That doesn't mean that someone needs a different kind of shoe. And there was a study that was done by Joe Napeck out of the military. And this is one that was really, for me, a very landmark study because I used to prescribe this way. And what they did is they took individuals and they looked at their archite. And those who had high arches that considered stiff feet, right, were put into Christian shoes, those who had low arches that were sort of pronated, they put them into motion control shoes, right. And then those that were neutral, I think they put them into neutral shoes. And then the other, another, another group, they all got the neutral shoe. Everyone got the neutral shoe. And they followed them for injuries. And what they found, now, if those shoes matched to the foot type, we're going to, the reason they do that is to try to protect the foot, right, because of its its inefficiencies or whatever. You'd expect that the people who have footwear matched to their foot type would have less injuries, but that's not what happened. There was absolutely no effect. And they did this on a number of different groups like the, I think an army group might have been the Air Force group. So across different branches of the military, then they put them all together into a huge meta analysis, and they found the same thing. So I don't think it matters. I'll say that. I think that we, our bodies have not changed much in the two million years that we've been, we've been running. Let's just talk about running, right, because a lot of this relates to running. And then we can talk about minimal footwear in other populations maybe later. We've been running for two million years, right. We've only been using motion control cushion shoes since the 70s. So 50 years, 55 years, that's it. But we've been running for two million years. So up until that point, we were in either barefoot for the majority of that time, or in very minimal shoes, plim souls is what they call them. They're rubber souls and canvas tops and, you know, very much like a minimal shoe until the 70s until 1970 or right around that time. So we have, we are able, we have everything in our feet to be able to tolerate the loads of walking and running. And so let's just talk about the foot. So the foot is an amazing structure. It has 26 bones, 33 articulations, and those joints have six degrees of freedom. So three angular motions, if you decompose them into the carnal planes and three linear motion translations. That's a lot of motion there, right. And there are 10 muscles in four layers just underneath the arch itself. So people don't appreciate that. Those muscles are there for a reason. And the reason that they're there is really primarily for stability. They do act like spring suspense and research that shows that as well. But they help to, as the foot lands and the arch deforms down, which is helps with shock attenuation, they actually help to slow that that deformation downward and slow the velocity. So slow the magnitude and the velocity of that motion, right, which helps to protect the foot and helps to protect the planar fascia, for example, right. So those muscles are really there. They're very important for walking and running. And we can we've done it for for almost two million years without any kind of support and cushioning. So we've lulled ourselves into thinking we need it. And I would like to just talk about because a lot of people don't know this. How did this happen, right? How did this happen in 1970 that we went from these very minimal shoes to shoes that are maximal. And even some of these 4% shoes and all of that, which is another whole category now. And so what happened at that time is that it was during the running boom, right. All of a sudden, the general population wanted to run. And we could go into that. But let's just accept that this running boom started. Prior to that, it was primarily running clubs, collegiate teams, high school teams. And they were pretty trained. They were trained up. And they were running in basically, you know, racing flats. I mean, they didn't have anything to do. Probably could roll those up just like you roll up a minimal shoe into a ball. And so when that happened, they started out running in the same shoes that everyone else was running in and they got injured. And it's kind of like a no duh, right? Because they didn't have the controller, the cushioning ability to land on one foot with two and a half times your body weight. And so they ended up developing issues that were related to cushioning or too much impact, which is why we added cushioning, too much pronation, which is why we added all of the anti-pronation devices. And because they've been walking around in about two inch heels, most people did. Now we're into a flat and it puts a load on the Achilles. So what they did is they added a lift. So that's where the heel to toe drop came in, right. And so rather than adapt the runner to the sport, they adapted the shoe to the runner. And that was the big mistake. And they continued to do that. We got more and more cushioning. So now we got the hookah with this bunch of a midsole. And we have more and more support. You got the Brooks beast, right? So, you know, we ended up actually because it ended up really digging us into a hole, I think. And I got that information from someone who was working with Nike when they first started. And he told me that what they did is they actually had when they started to see the injuries, they called in three really well-known sports podiatrist because they were the ones dealing with these runners. And they're the ones that made these recommendations. And it's not that I think they were, I think this is what they really thought. I think they thought that this is the problem, and this is the way to solve it. And they actually paid them as consultants to come and tell them, so Nike started to adapt the shoes to the runner. So this is really caused us a problem. It's just like we want these really comfortable chairs, like chairs, like bark allowzers, right? I mean, they're very comfortable and they let us raise our feet up and they're, you know, super comfortable. Are they good for our backs? Maybe not. So, you know, really what we should be doing is we should be squatting more. That's what we did as, you know, as hunter-gatherers and not sitting. And, you know, we, so we're not going to be able to go back to the prehistoric days, right? We're not going to go back to caves. We're not going to go back to hunting and gathering, but we have to do things that allow us to get as close to the way that we adapted to move so that that mismatch theory of evolution is minimized. And again, to review that mismatch theory, it says that our body, our environment is changing faster than our bodies can adapt. And so our bodies are mismatched for the environment and they are. So instead of, you know, taking the car everywhere, we need to, we need to interject more walking or we go to the gym. We don't have to go to the gym as hunter-gatherers. We, our day made, gave us the exercise we needed. But now we have to add that in. And I think minimal shoes is the same thing. It's the same principle. We need to get away from things that are taking the place, the muscles and the beautiful structures of the foot that we have and allow our bodies to function the way they were meant to. Yeah, I love that explanation. And the way you think about that, I know elsewhere, you mentioned the importance of active standing. Now you're talking about active sitting. And it's funny because in this world where we're trying to increase comfort, increase conveniences, you know, we're here advocating. And not the first time, of course, that's we're all about. That's where we think we all get well together, right? It's exercise science nerds. I want to come back and talk about loading patterns, particularly. I think, you know, I like that you said, maybe it doesn't matter. And I'm an academics, as we were talking about offline. And I think sometimes we, and you also want to find yourself as a clinical biomechanist, which I love, by the way. And so when you're taking all these biomechanist classes, right? And I'm talking to my trainees about how austere arthritis predisposes the medial knee joint in this and that. And we're evaluating all these postures. And then how do we, how do we, you know, align that thought process with kind of what we're talking about here? But I think maybe let's stay on the striking patterns because you talked about the whole running boom and why this even became an issue and why this became a conversation the first place. So would you care to just high level give the, the definition that you talked about, rear foot, forefoot, midfoot striking. And maybe, you know, some specific sports where forefoot is going to be obviously more advantageous. And really, that's like sprinting things, things of that nature. And then how those patterns distribute force and load on the respective tissues. Great question. So let me define what the different strike patterns are. So a rear foot strike pattern is one in which the heel hits the ground first. And a forefoot strike pattern is one in which the ball of the foot hits the ground first. And a midfoot strike pattern is one in which they hit the ground together. So that's the way that we classify those three strike patterns. I believe that we were designed. And there's lots of, I could really cite a lot of different reasons, rational, scientific, rationales for why we were designed to land on the ball of our foot. And so I think in terms of running, walking is meant to be a heel strike pattern, right? When you walk, if you look at the modeling of walking, it's modeled as an inverted pendulum, which is basically our center mask goes up and then down as you walk over your step over your foot. Whereas running is modeled as a mass spring where the center mask actually goes down and then up as you load the foot, your knee flexes, your hip flexes, and you could the center mask goes down. There are two very different activities. And I don't think that running is just fast walking. When you land on the ball of your foot, you're taking advantage of the beautiful long Achilles that we have. You don't need as long, you don't take as much advantage of that long Achilles when you land on the heel. I mean, there's lots of reasons. If you look at the stiffness of the heel pad versus the forefoot pad, the forefoot pad has greater stiffness and is able to attenuate better the loads of landing on the ball of the foot. If you look at, there was a study done by Dan Lieberman out of Harvard and he looked at a group of runners from the area of Kenya where a lot of the elite runners come from. And so basically what he did was he had these runners and he classified them as those who are always their footwear patterns, always shod, sometimes shod, sometimes barefoot, sometimes barefoot, always barefoot. And then they videotape them running across a field. And what they found is that runners who are always shod land on their heels, runners who are always barefoot land on the ball of their foot. And the more time they spend being more, with less shoes, the more tendency they have to be a forefoot striker. So I really think that forefoot striking is our natural running pattern. It shortens your stride. People talk about increasing cadence. It automatically increases cadence, brings your foot underneath you more. So there's lots of benefits. It also reduces the load to the knee. So when you talk about the way that the lower extremity gets loaded, when you land on your heel, there's a greater load at the knee, less load at the ankle or the calf. When you land on the ball of your foot, it shifts the load to the calf, but reduces the load at the knee. And when you think about the injuries that runners get, the majority of the most common injury in runners is knee injuries. So I just again think that this is really was our natural strike pattern. Now that same study that Lieberman and colleagues did, they also looked at the variability of foot strike in individuals who are barefoot or individuals who actually run in shoes. And what they found is that when you're barefoot, you have greater variability of your foot strike pattern. So if you're on soft surfaces, you might land on your heel. And then when you're on hard surfaces, you've got a softness so you land on the ball of your foot. So they vary their foot strike depending on the surface. If the heart of the surface, the more tendency of a forefoot striker, whereas rear foot strikers, I'm sorry, those who are shot and basically use a rear foot strike pattern no matter what the surface is. And that's really important because the injuries that we talk about with runners are overload injuries, overuse overload injuries, meaning that you're getting the same kind of load every single time. But if you're barefoot or even in minimal shoes, you have some sensory input, you tend to change sort of the distribution of that load more. There's more variability of loading. And so it doesn't, you don't have as much of an overload issue when you, you know, land, just a little bit different every single time. It's wide trail running, even if you're in shoes, trail running has associated with less injuries than road running. And it's not because the road is hard, it's because the road is the same every single time. Whereas trail running, you know, you're running over branches and you're changing your foot strike and you're, you know, you're changing the way that the leg gets loaded with every single foot strike. So that's kind of a little bit about the loading and foot strike patterns and how they result in different kinds of loading to the lower extremity. Yeah, I can also endorse, you know, I've been doing the minimalist footwear running now for about a year and a half. And I remember the first time I did it running outside on the concrete, I mean, there was no way I was going to land on my heel, you know, and experience that type of pain. And so you're essentially forced, you know, to get on your tiptoes, shorten your stride, increase that cadence, and almost have this different running pattern, this different gate pattern, right, which I'm definitely interested in asking you about. But some of the other things, you know, I've realized is I'm a lot more in the present moment. And I believe most of our cancer receptors in our in our foot are also near our toes rather than the heels. So you're actually getting better appropriate reception, better control as you are running. One of the things I was curious about though is that are people who are in shot who, you know, might have a seven millimeter eight millimeter drop in their shoe? Is it okay for them to use a four foot strike? Because with all this talk about minimalist footwear and having a four foot striking pattern, I'm hearing people who, you know, are not wearing minimalist shoes, try to attempt that. And I'm wondering if that's advantageous still or is that's going to lead to actually more issues? Yeah, it's a really good question because I think a lot of people don't think about this. So in my in my journey, I'm at the University of Florida now, the University South Florida, but I was at Harvard University and that up there I had developed a running clinic that was associated with the lab. So it was basically the lab helped to answer questions. The clinic could generate the questions so they really went hand in hand. And we saw a thousand runners in that clinic. And so we had many people that came to us that had transitioned themselves to four foot strike because they're red borne to run. They've heard maybe it's better, but they ended up with injuries. And I don't have a study. There's not been a study it done. I've been trying. I have not been able to get I had one. I submitted one to NIH. NIH just doesn't. It's tough. That's a tough group. It's tough to sell them on minimalist shoes. But it was comparing sort of, you know, four foot striking and regular shoes versus four foot striking and minimal shoes versus, you know, all like all different Kent combinations and how that affects both mechanics and injury. That was that was what I really wanted to do. I'm not yet been able to get that funded. But if you're going to run with a four foot strike pattern, it matters what for where you use a lot of people have tried to go from go to a four foot strike pattern in the same shoes. They don't want to go through the it takes some time to adapt to minimal shoes because it's kind of like an exercise that puts greater demand on the foot muscles and and the kill is and so a lot of people don't want to go to the minimal shoes and they don't want to lose the cushionings. They think I'll just change my foot strike pattern. But the problem with it is that because you have this heel-to-toe drop, it puts your foot into a planar flex position and then you want to planar flex the whole and your foot is flat on the ground but your planar flexed in the shoe and then you have to get your heel off the ground so you're in greater planar flexion which puts a greater load on the Achilles. And so what happens is you still have to get the foot planar grade and you've got to go through greater range of motion and dorsi flexion in the same amount of time and so it you end up with greater dorsi flexion velocities which puts greater load on the Achilles tendon so puts it at risk for Achilles tendonize. If you look at it from the front view, you land with more inversion because you have this flare. The shoes have flares on them and so you land on the flare which puts you further out and everybody lands in the outside of their foot but the flare actually causes you to land in more inversion so then you've got again you have to go through greater range of motion in the same amount of time to get your foot flat by mid-support so you have greater eversion velocity and it's supposed to your tip that helps to prevent that it helps to control that so puts a load on the on the posterior tip. You also can get a load on the perineals because if you land in a lot of inversion not the perineals are acting eccentricly to hold you up right to prevent you from rolling over into inversion so it puts these increased loads. You also have a greater when you land in a pair of regular shoes as a forefoot striker. You have greater anterior posterior impacts and you have a greater maybe lateral impacts and in fact the overall impacts are highest if you forefoot strike in a pair of regular shoes they're higher than rear foot striking in a pair of cushioned shoes regular shoes so it's just not a good thing to do and I always say if you want a rear foot strike that's fine I'm not going to try to change your mind where a pair of shoes that have some cushioning because you're going to land on your heel and you need it right try to get shoes that don't have a lot of flare because the flare causes increased moment arms or levers and they cause increased moment arms and cause increased loads on the foot so try to find a shoe that actually has very little flare and little heel-to-toe drop and some cushioning if you want to run with a forefoot strike pattern I suggest you run I would prefer you running in a pair minimal shoes you have maximal sensation but at least run in pairs shoes that have again very little cushioning very little flare very little if none no heel-to-toe drop yeah Dr. Davis you know you're mentioning a lot of these terms I wonder if the audience is able to keep up a little bit right I mean I know Al-Tomashan I kind of studied this but you mind just quickly basically going over the criteria of a barefoot shoe and maybe what you know motion control means what cushioning actually means I even have my shoe here too have as a model in case anyone wants to go to YouTube and and watch with the airsoft in terms of what defines a minimal shoe so a minimal shoe is one that has no midsole so there's just an outer sole on this shoe to provide traction and you know protection from the ground it has no heel counter so no stiffness in the heel counter right there's no arch support inside there they they're wide in the across the ball of the foot and you can roll them up in a ball that is a minimal shoe and I'm sure you can do it with your shoe yeah absolutely your shoe up it makes for a great travel shoe right and there was there been a couple of studies that have shown like that shoes that have just a little bit of cushioning people still land on their heel because as long as you have some cushioning there you feel like you can land on your heel but you might end up with greater impacts because you don't have enough cushioning so I there's what I'm going to call them partial minimal shoes they don't have as much cushioning or as much arch support they kind of in between and a lot of people want to do that sort of in between but I don't think it really is beneficial to go that way I think you either have cushioning under the heel see protect yourself or you don't and you utilize your your own muscles so that's that's a minimal shoe in terms of do you want me to go through like aversion and dorsiflexion and yeah go for it okay so when I was talking about how you land planter flexion is the angle of the foot when the toes are down and the heel is up right and so when you land as a forefoot striker you land on the bifur and then your ankle goes into flexion that's called dorsiflexion in versiony version you're landing on the outside of your foot and the foot rolls in it's it's often called pronation that's another term for it so some people may be more familiar with the term pronation or the rolling in of the foot and those things are exaggerated when you forefoot strike in a pair of regular shoes yeah I I love that you had talked about that it's more than just the sacral plane right I think even as somebody who has been invested in this for over a decade and I think maybe the vibrams came out the first original vibrams with like the five finger ones right to 2009 down 10 somewhere around that career and I remember it was and so I you know before medical school I had a career as performance coaching working with athletes and so like I was one of the first people to get that and remember training and you know I'll talk a little bit later about how my the evolution of thought is kind of where we started out with that and how we bring it back and look at big picture but you know I would always just think about this in the sacral plane right pro like in terms of four foot versus rear foot mid first strike and you're talking about that flare which I've been fooled because when I look at I'm like oh great that's a wide toe box that's actually good for somebody I like I see a lot of patients with maybe Alex limitis or Alex rigidis which is really arthritis of the big big toe joint right mtp joint and for them I'll always recommend hey you actually want some cushioning and maybe some a wider base toe because you don't want that to be tight in there but that's maybe not the case right that flare is actually making it more difficult or your brain is lazy and so you don't want to bring that foot up and you're actually robbing yourself because you're not activating them push your tip like you're talking about so that I love that the other point I think with respect to people who have that excessive plan of flexion and not only is it making harder for you to go into that you know four foot strike but when they're wearing the shoe in just regular day life right going from point A to point B and they're not actually using it just for running purposes and that becomes your everyday issue now you've got resting plan of flexion all the time and eventually right we see a lot of people who have this Achilles centenopathy nowadays I've been getting a lot of consoles because people are freaking out about rupturing their Achilles because we have so many professional athletes doing it and they have these tight and stiff Achilles tendon that doesn't have any elasticity and so you get that 34 year old who's rupturing or injuring their after their triumplied basketball and so anyways if you don't you know preserve that elasticity and that stretch of that tendon you will have quote unquote a resting contracture not a true contracture but you know what I'm getting at so that's another reason that you know you might be adding insult to injury no pun intended there but I'd like to shift now darshan unless you have follows about this this running stuff it to talk about kind of the daily loading and maybe some of the other places where it's not necessarily running right so talking about the lifting athlete the cross training things of that nature is how might that change the kinematics right particularly as we look up the change for instance I'll get a lot of people and I think for me my primary thing is not not running it's it's going to be weightlifting right and so strength training so if I'm doing you know barbell back squats like how might they change the load and I think maybe we can look at it as you know when we think about the most common overuse as we get elderly population we have people living longer we think about knee osteoarthritis right and I think people will know right knee osteoarthritis we've talked about this before the middle part of the joint right so it's a tri compartmental joint and the middle part is going to wear out the fastest and when we're looking at it I alluded to this earlier I'll tell my trainees okay look at that foot right if it's pronated right you're gonna have that knee is gonna have more of a valgus collapse which means kind of like knock-neap-type situation right and therefore that's gonna wear out a little bit faster now when you mentioned earlier like I'm not really sure any of it matters I'm starting to think is like how much of it is this us spending time in bi-mechanics and finding reasons to be able to teach people so we can give them questions to answer on a test versus how much of it actually matters in that clinical context when we take a big step and look at the big picture so I know I give you a lot there to handle but I know you're up for it yeah so I'll take that question as how can how can minimal shoes be applied across a variety of different populations and again I'm gonna go back to my research and the way I treat clinically is based on this closer we are to the way we're adapted to move the less our risk for injury the closer we are to the way we're adapted to move the less the risk for injury and so you know I think this applies across the whole population I think the kids should be in minimal shoes let their feet develop and barefoot too barefoot too but you know it's nice to protect your feet at times I understand that and I'm not like you have to be barefoot but I think barefoot is awesome and people need to spend time barefoot we're barefoot all the time we never have shoes on in the house and I wear flip-flops all year round now because of the University of South Florida so it's great but you know kids need to we need to get kids they'll they'll adapt I think a more efficient running pattern I think that things will adapt naturally because they're they're they're allowing the all the natural input that they're supposed to have in terms of sensory input in terms of the mechanics et cetera in terms of adults even walking so we conducted a study this was in concert with Sarah Ridge in at BYU at the time and it was a study of they were these were collegial aged individuals and they we had three groups one group walking regular shoes one group did a foot strengthening program and the other group just walked in minimal shoes and we looked at the cross-sectional area of the muscles of the feet in all three both at baseline and at 12 weeks I think four eight and 12 I believe yeah and what we found is that people walking the regular shoes there was no change in it and you wouldn't expect it there was no impetus for change the people in the foot strengthening group their muscles got stronger they got bigger and a bigger muscle is a stronger muscle size relates to strength the people in the walk who just simply walked in minimal shoes their foot muscles also got stronger to the same degree except for one muscle and so what that tells you is just simply walking in minimal shoes make sure feet stronger and a strong foot is going to be a healthier foot it's going to be less risk for things like plentifashioitis because plentifash is more protected because you have that first line of defense just strength all the way through the foot right so let's take it now and now most to add to answer your question about the other other areas weight lifting is a great one because how important is it to be able to feel the ground when you've got that kind of weight on you I don't do that kind of heavy weight lifting my husband does and he does it in these kind of shoes not not pink ones but he does it in minimal shoes and he feels he can feel the ground he feels he has more proper better proprioception now you don't want to take somebody who's been you know lifting in like maybe supportive cushion shoes and put him in a pair of minimal shoes right away because they don't have this strength you have to adapt and this is honestly where minimal shoes got the bad rap 10 years ago whenever it came to 2009 2010 people fought it's just a shoe right you just put it on you do everything you're doing before and the problem is it's like going to the gym as your example lifting 100 pounds when you've never lifted before getting injured and having the community say oh weight lifting is bad for you don't do that no one would do that they'd say don't do it that way and I have spent the last decade trying to tell people don't do it that way so I think that you know it's in anything it's really important for us to have as much sensory input and to have things that provide that promote foot strength as much as possible now let's take it and the next to the next age group right there was you tell me you mentioned neo a one of my colleagues from Brazil Balsaco did an amazing study where she took women who were 50 plus who had documented neo a and and randomized them into walking in regular shoes versus moleca shoes if you look them up online they're they're basically 15 dollar minimal shoes they're like minimal shoes they're very inexpensive and a lot of people don't have a lot of money down there actually walking them but so she randomized them so she's putting up these people with documented neo a who are in pain medication and have knee pain in minimal shoes it's kind of crazy right and she followed them for six months and she monitored their their pain medication as well as their biomechanics and their function and they had significant improvements in their woe mac significant reduction in their pain medication and significant improvement in their knee mechanics because to your point shoes tend to put you into more supination or rolling over and that rolling over puts your knee into that various position which actually loads the medial compartment right when you get into minimal shoes are in barefoot your foot rolls in and it kind of distributes the more equally that load across the knee this is they did no exercises in this in this intervention it was simply minimal shoes so I think that's amazing right and then this is an injured population there have been studies now that are coming out looking at at people who are aging and finding that because you know I it makes me crazy when I see these people in these huge shoes right support big clunky supportive shoes they can't feel the ground they have them they have large moment arms large lever arms because they're they're really flared and they don't have it can affect their balance and they showed that in minimal shoes balance and stability is improved so it's across the board minimal shoes I think again and it's just simple this is not rocket science this is just let's let's do what we do to every other part of our body we don't support it sort of sort of I guess bras and tux straps but we we basically just we our clothing is really just to kind of protect us and to protect us from the sun and the wind and the rain and of course we're all fashionistas but but for some reason we've gotten to this idea that shoes have to support our feet and our feet can't do it themselves and we have to get away from that thought I've told my grand I've grandkids and I keep them in these kind of shoes and I tell my grandson because there was a study that came out that showed kids ran faster in the minimal shoes and I tell them that they're his fast shoes these are your fast shoes so we just you know we got we got to start putting a little sparkly lights in them so little kids will love them there needs to be some kind of campaign that gets us started because I believe that so much of the many of the provinces getting off just the foot that we are dealing with in middle to late life have to do with what we've done early on and if we could change that we could change all of this we're putting a bandaid on or the way and I treat people too I treat people in the OA who already have the no total needs and but if we could get it early on that to me is the holy grail yeah and that leads perfectly into what I'm about to ask you here so you know I love to bucket this topic into lifestyle medicine and you know with lifestyle medicine we know that early exposure plus lifetime exposure really make it different when it comes to health span longevity preventing injury when we start to build awareness around barefoot shoes you already mentioned trying to get it to our younger population and rightfully so I'm guessing that we're also telling it to people who come through the physical therapy clinics and to ultimation eye with pain but where do we find the biggest bang for our buck is it truly just looking at you know parent teaching parents what type of shoes they need for their kids and then the other question I'll ask is is there ever a point of no return where for somebody they should absolutely not be touching barefoot shoes well I'll answer your last question first and yes you know I've learned in my career my life never say never and never say always right so not everyone should wear minimal shoes and if you have the reason for using minimal shoes is because you want more sensory input but if you don't have sensory input if your sensory system is impaired like in diabetes peripheral neuropathies and you can't feel when you've got too much pressure under your second meditation head you should you need cushioning get a pair of cushioned orthotics and you know if you've got rheumatoid arthritis and you've got deformities and you when you load is a lot of pain you need to accommodate that there are going to be cases where people should wear something other than a minimal shoe so yes but the other thing I've learned is that I don't know what the right left limits are of who can wear them because I had a woman she was a PT and she was in her mid-50s and she'd been wearing orthotics her whole life and she had an arch that honestly looked like this it looked like Shakomari tooth syndrome and she'd actually been diagnosed that and undiagnosed it because she didn't have the sequela other sequela of symptoms she as she's a PT her husband's a physician her to her daughters are all in medicine PAPT nurse nurse practitioner I think and they all have kind of bought into the minimal shoe sort of idea and they came to one of my this was the ACSM American College of Sports Medicine they came to one of my lectures and she came up to me and she said you know I want to try this and I said but yeah I'm looking at your feet I don't know Shaba nothing seems to help so two years later fast forward I'm in Boston at the meeting the ACSM meeting there and she comes up to me and she is walking in a pair of five fingers their feet are kind of still she it's not changed her arch but she's walking in five fingers and and I was just amazed I said I can't believe you did she goes I just started doing exercises for my feet and started slowly and she to my feet have never felt better than the only thing I'm comfortable in she and her husband had just walked the inca trail want to peep want to peep you in those shoes not in hiking boots right a lot of people are in hiking boots when they when they walk that inca trail right no no she was in these minimal shoes right what what a testimonial and I would never have said you should wear those those that was that high arch stiff foot that right so that's what I've learned we had an individual who had no toes she'd had sepsis and this was at the running clinic when I was at Harvard and she lost it they were amputated right and and people had her in these big heavy shoes and she just wanted to run she wanted to be able to wear high heels at her daughter's wedding and so we worked on her feet we worked on the strength of her feet we had her walking in minimal shoes we didn't ever run in the minimal shoes because she didn't have the toes with something kind of a low profile shoe for her um but again there I mean so I I think it's worth trying with people um but you also have to be smart about it and you have to be clinically astute you know you don't want it again to do no harm right that's that's our mantra we don't want to harm anybody but at the same time I've given more fee to chance as I've gone on so that was that question now I forget what the first question was that's all right I was just talking about what the biggest lever is that we could pull to really spread this campaign this awareness you mentioned you know the younger population um but what about you know how do we have these discussions with colleagues because I have a lot of them with my co-residents with my attending today and he said make sure you ask Dr. Davis because I have really flat feet so you know how do we how do we have these conversations yeah I think um well I think we have to have more and more people having the conversations it's like anything else it's like smoking and littering look what we've tried look how we've changed the world in smoking I mean I know there are still countries to do but you know we we have this campaign and even littering like you tell them see people throwing things out the window right there's I think we just gotta have to have more and more and more people that's why I'm really excited you guys are really excited about it more people talking about it but I think there are certain communities that we have to get into and one of them I think is the pediatric community so pediatricians and physicians who deal with children and then even in geriatrics right because remember I just said there and what I my my ammunition is research and I have a drawer of articles that I'll pull out and say here's a study that shows that walking in minimal shoes increases foot strength right here's a study that shows the people elder elderly people have better balance in minimal shoes here's a study that shows that people with neo a actually did better with minimal shoes so I think that research helps certainly to to back it but you know I I've had people say to me Irene it's not the research that gets the whole general population excited it's marketing like there's that's why I'm wondering like do we need to have a big marketing campaign right and how do we do that um to really market that these are cool this let your feet free your feet you know all of those kinds of things um showing kids running barefoot and showing you know feet and all kinds of different positions and showing what feet can do I mean if people should be able to do this with their feet and so many people can't right I mean you have the same yes exactly you have the same muscles in your feet that you do in your hands you have an abductor digi-digity minimi to be able to do this and most people can't so with one of the things that we do in the clinic because we teach people how to do this it takes a while and having those toe spreaders helps because it gets the muscle and a better length tension to actually kind of act that's why they it's widely they help it's really kind of it's hard to start from here but if you start from here and go out it's a little bit easier so doming and and toe spreads and toe yoga and and he'll he'll um he'll lift and all of those kinds of things are are obviously really important for that um yeah so I you know I I have really scratched my head um I am going to be meeting with someone at the PT meeting in next week and we're going to brainstorm about this because it sometimes keeps me up at night thinking how do I now really want people to once people once people experience it they believe it right yeah they believe it I have had so few people except for people who have done it too quick too soon and gotten injured but most people who go to minimal shoes will never put a pair of the kebi shoes on again they feel really yeah I can't go back weird I can't go back yeah right I know do you guys have ideas so I was actually about to ask you what about therapy like our our therapist how much of the education are they getting about this how much of the population is actually talking to the patients I come into these clinics because I'm thinking also about writing a script for physical therapy when I see patients say you know this patient would probably benefit highly from doing foot exercises um going barefoot actually in the gym and working on balance and sensation and I'm always thinking about well how do I write this script out so that the therapist actually knows um and it's comfortable with it so from your experience what have you seen so um we wrote a paper a foot card it's called the foot core paradigm I think and I can send that to you after the this after we get done pat McKean is the first author but we were sitting around a campfire at the International Foot and Angles Symposium in Kentucky and we were we were some was playing I think there was a little bourbon involved but we were all sitting around and we and I was lamenting that my profession doesn't appreciate how important the muscles of the foot and the foot are because they just published a guidelines it's basically um you know guidelines for how you treat plantar fasciitis and it included a lot of really good things but strengthening was very obviously missing from it it was like there's no muscles in the foot but every other clinical guideline they have you know uh biceps tendonitis and and patellar tendonitis all those involved strengthening with the foot didn't and so we wrote a paper and it was myself and two other individuals who were athletic trainers and we also asked Dennis Bramble who is a evolutionary biologist to join us in this paper and we wrote a paper to introduce the idea of foot core just like everyone sort of bought into and it's a concept it's really a concept even the lumbol pelvic core it's concept that we have these small muscles in that area that when they contract there's that they don't generate large force but they stabilize so the primaries can do their job same exact thing in the foot these these muscles these intrinsic muscles are small small cross-sectional areas small moment arms they don't generate a lot of force but they're very important for stabilization and we talked about that and you know that paper got downloaded a ton and it really I think started a new and I'm not sure I'm not the first person to thought some sure other people were thinking about but it started this sort of wave of yeah we need to pay attention to it and now you see foot core being taught in schools I know we teach it and of course I'm going to teach it in our program but I see it in other programs um and and I think it's and I have actually had patients who reach out to me and they'll tell me that their therapist did these exercises the one of the first things I'll ask them so it makes my heart sing to know that people really are doing this now but you do still need to find that right therapist right so um it's all about relationships like I people say to me like how do you get the physicians to buy into the runners and minerals shoes I said I develop a relationship with them and they trust me and I provide them the research we have conversations right it's it's more it's not just I'm going to refer it's like I need a relationship with this person and I think having those relationships and knowing the people in your community the PT's that actually do understand the importance of foot core in finding those people and then they become sort of a good conduit to you for those kinds of patients um so that's I think it's important but I do think more and more the whole concept of foot core now I think that paper came out in 2016 I believe and so it's been a number of years now and I think it's really kind of caught on so I don't think it's going to be something that's you know new you know I love that I think you know the lumbar pelvic core is much more popular in both you know all disciplines under health care particularly because the back pain is probably much more prevalent in terms of something right people talk about non-specific back pain or every single person throughout their lifetime at some point has had a back issue right and so we try to okay let's try to strengthen and stabilize everything around it to take some of the stress off the structures that might be contributing discomfort but you know as my boss always likes to talk about he's a runner too but he he will tell his patients all the time listen like everything starts with your feet up right and in fact when he did so we do a lot of manipulation nasty path manipulation you know different types of treatments and he'll always start with the feet looking up and then say look that's your first interaction with the world right so if things aren't processing correctly there everything up the chain might not be moving the way it's supposed to be and that's going to maybe put undue stress in places that's not supposed to everything that we've talked about in this first hour so I do think that's really really important you know shifting to kind of for folks who are later in life right so maybe somebody's listening maybe a 35-year-old runner who is really not quite ready to to hang it up and intends on playing sports or running a really any athlete for the next 10, 20, 30 years they're sold now right Dr. Davis is okay to listen I got to really take this this this foot thing seriously and you know utilize these muscles and train them just as seriously as we train our level pelvic core and other muscles I'm wondering how might one start and then the other thing the second part of that question would be for the general population for the weak and warriors right for the busy professional right such as the three of us maybe we do understand that there is a return on investment right so we talk about your researchers so you're you're you're teaching you're publishing papers and stuff and there is a finite amount of time that we can spend training right so you've talked to Peter T.A. before right he's a big proponent of Zoan 2 cardio right how many hours a week do we spend on that how many hours do we spend in a week doing a start training and then recognizing that if we're going to spend 10 20 30 40 minutes the dose to get that foot core stabilized and firing properly I'm curious how you think about that and how might you when you look at a weekly program or monthly program for an athlete how much time would you spend on addressing the foot core specifically maybe not necessarily in the rehab phase because we understand that you have to you know give it some more energy but maybe more from a pre-hab preventative standpoint in terms of trying to prepare like for and when you first started talking about this I was thinking about like you know how do you prepare somebody to go to like running and walking in minimal shoes and and how do you how do you get them to train this area of the body so that it can do its job and it gets it depends on kind of the job you're going to ask it to do right so if you're just walking you can if and if you don't have any foot related problems like planar fasciitis and you haven't been in orthotics so those are a lot of ifs so you got a pretty relatively healthy person regardless of their age honestly not somebody we see in our clinic right I know I know but they can walk in minimal shoes without much preparation because the demand is not that great now you don't want them going out and walking five miles right because that can cause a problem right away just like anything else but they could start out you know you know wearing them around the house and then going out and doing some walks and you know the the risk is very low when somebody is just walking you're got 1.2 times your body weight maybe up to 1.5 your wrist walking it's running running it's 2.5 times your body weight and you've got only one foot on the ground coming down with that it's a series of single leg landings you have to prepare right the way that I prepare my runners is I start walking because I know for a fact now based on our research that they're going to get stronger just from walking so at least get a base strength from walking in the minimal shoes right and then if I want them to run then we're going to do some progressive foot core program and this is going to involve things like there are some really basic exercises and I'm not sure if this is what you're getting at but things like doming short foot exercise where you press your toes down but you keep them straight as much as you can and you pull the ball of your foot back towards your heel and you hold it and then it's called don't it's short foot exercise because your foot actually gets a little shorter your arch raises and you hold it right and you start out by doing that you can do it sitting if you're not very strong and if you get cramping it means you're really weak so usually they do get cramping and then you do it in standing right and then you do it when you're standing in line for the grocery store you just you just do incorporate it into your daily activities just like active standing which we really can talk much about but it's part of active standing right and then you start to increase the load like you would in your when you do weight lifting you basically have them start doing single leg hops or double hops so doming and hopping and then doming and hopping on one foot right and then doming and hopping off of a bench or two feet and doming and hopping off a bench on one foot and then leaping from foot to foot to foot to foot those kinds of things and you can add weight so you can progressively increase that load so that they're able to keep those muscles strong and and once they once you start to activate them and I don't have research to show this but my my assumption is that once you get those muscles acting they're going to start to be more active in all kinds of activities that you engage the ankle and foot and the prime movers and they're going to help to stabilize so that once you start to do those higher level activities you'll have that basic support and then in terms of just I just do want to say one thing because people ask a lot about how you would transition into running if you're healthy like you just want it you want to try to do this what I tell people is you know make sure you can walk in pair minimal shoes for 30 minutes briskly a 30 minute brisk walk in minimal shoes once you can do that and you're not having any problems then you slowly replace you're walking with running right so and you take take it into three ten minute blocks you do run for one minute and walk for nine run one walk nine and slowly replace the walking with the running so that now you're running 30 minutes in the minimal shoes and you don't do it all once you do you know take a day off in between and if you have any pain you back off one you know and stay at that same level give yourself a rest but slowly bring it up and then once you're running 30 minutes then you can start to increase your speed and you can start to increase your distance in your and in some of the hill work and things that you want to do but it needs you need to give your body time to adjust it's not just a shoe yeah the audience can take it from me I transition way too quickly just into running and I mean that's my personality when it comes to sports and running and whatever fitness I'm just going to do it and I my left Achilles you know there's a lot of strain there even now walking uphill so I definitely transition way too quickly to now where I run three miles you know I'm getting some clotication symptoms so yeah don't do that take it easy and uh you'll you'll you'll you'll fare much better so I'm trying to rehab that a little bit start low go slow right Darshan remember that there you go start low go slow I love that um so thank you for for those tactical tips I think that's really really important right I think oftentimes we'll see somebody and again you know it's interesting that you were asking the question is how do we get more people to buy in and I it just goes to to to show one that you know when you live in little silo or you have your own biases because I thought living in that world that I talked about we're seeing a lot of these athletes who were kind of invested in their own performance and folks who were rehab minded and then going into physiatry and then going to sports medicine this is majority of what I would see the people who walk into my office are not healthy they're not looking to optimize performance they are injured and they will tell me this story right oh I heard this podcast medicine we'd find Dr. Davis talked about this and I started doing this and now my foot hurts right and I'm like oh god right and so for and so in my mind I was like okay man this pendulum has swung too far about this barefoot craze yet you're out there in the world you're at these national academy meetings you're having these conversations and it seems to not be the case right so um I really truly appreciate that and you know I'm excited of maybe giving another try I will I'll tell you like you know for me personally you know I've started developing some early osteoarthritis in my big toe and so for me it's been a challenge and so I have to like put like a dancers pat in there and maybe include a foot that has a little bit of rocker but now I'm starting to think I'm like well when somebody came in with knee osteoarthritis I wouldn't necessarily put them in a brace I would say a list and this is to be like give everybody I'm like we have to strengthen the surrounding structures to distribute the load off the joint well maybe it's not that much different when we're talking about the big toe joint right do you agree with that yeah you know it's interesting um I've had people who have had things like that that you would think maybe putting them in a mishu would be what make it worse and it's made it better and that's very anecdotal but um I think that what happens when you're in a mishu especially if you get a nice wide one and you know like you said I think the beboes are really nice and wide the um I think the zeroes also give you that with and even going barefoot honestly what happens is you land and I wish I could show you this video it's it's christmic doodle running in slow motion if I'm a front view and you can see how you go across and the foot splays and the distribution of the load goes across all the metatarsals when you land even if you're on the ball your foot and a pair of shoes that are stiff it's this this but it's I can't make my foot do it but you're going through every single metatormsall so you distribute the load in a different way and it may be that it doesn't load your you know I would try it why not yeah I would go slow and see if you can you know tolerate it slowly and if it if it makes it worse of course stop of course the other one you because you brought it up twice right planter fascia it seems to be very very challenging and you know people will think the tree is that right and so maybe we could use a case study right so let's actually I was talking about my boss earlier you know he's had some of these experience hopefully it doesn't mind me sharing at this point and you know and he is like I said he's a runner and of course like any old runner he asked me to take a look at it and then then yeah I was like yeah you probably want to lay off this a little bit I maybe see a little interstitial tear and then he read you know 10k the next day so that's just goes to show you how runners are yeah but but I find that to be very very challenging particularly because they'll maybe go to some clinicians and they'll get a couple of cortical surrogate injections and they'll come to you and we're going to be very very limited so that helps with pain but you know I've heard many stories again a little bit of bias about you have planter fascia rupture a kiley sender rupture that kind of stuff where you don't necessarily want to keep juicing it up what's there and to help with the pain you might want to address some of the surrounding structures you mentioned planter fascia and then you have four layers of muscles just on the bottom of the foot would you care to talk about a runner who maybe has an acute on chronic planter foot pain let's call him to be 32 years old and training for a marathon right three months out and is now starting to have like achy bottom of the foot pain and all their classic history how might you approach that and this is a person who is not in bear for training right they're doing their Brooks at this point yeah and I've actually got an exact I really good case so we had an individual who is probably 27 at the time a guy who had had knee pain originally a while back and was given orthotics right for his knee pain but they they didn't really help so he kind of threw them away but then he started doing a lot of walking and I think you know my my interpretation of that is that he wore the orthotics orthotics will make muscles weaker and there's a study that shows that 12 weeks of orthotic use results in a 10 to 17 percent reduction in the size of the muscles right so so I'm assuming that yeah he you know he wore them for a while then he threw him away but he was doing a lot of walking he developed this planter fascia and it started in this just terrible cycle like I think he went to England he went to England and he did a time he was walking all over the city and he went through and I won't go through his whole history but he had had steroid injections he had had surgeries he had had shockwave therapy he had had I mean everything you can orthotics choose everything you can imagine and nothing made it better and his feet weren't a little bit on the low side in terms of the arches they weren't completely flat he could not stand to wait for a bus like in the city like he was in Boston I think he was a doctoral student or maybe postdoc he couldn't wait for a bus and he couldn't take care of his two-year-old daughter because he couldn't run after so he was disabled at the age of 27 because of the foot pain it was so severe he came to us and he said I want to run and I said well let's start with walking right so what we did and we did this over the course of probably a year and maybe 15 months I think total where he came in and our first goal was to have him walk and so we started to we he didn't have orthotics because he'd thrown them away but we started working on strengthening his foot and we strengthened his foot we got him into minimal shoes but had him just wear them very slowly slowly graduated into him we were working on all kinds of things like really I believe in working in everything all the way down at least from the core down the level pelvic core down so he was really working a lot of things but focusing on the foot we got him to the point where he was able to walk in the minimal shoes and we sent him on his way for a while because we wanted him to just kind of get used to that and then he he got a job over season Europe and he before he left he wanted to be able to run so he was having a little bit of every time he tried to run this having a little bit of knee pain so we did some retraining and I won't get into the gate retraining stuff that we do but we were trying to realign his knee through gate retraining but we also worked on no further development increasing the load on the foot muscles so increasing the demand adding weight so those kinds of things and in the end he was able to run in minimal shoes he was running on the ball of his foot and minimal shoes this is a guy who had had probably five years of plantar fasciitis with all every single treatment you can imagine and including surgery and nothing got him better and all it was really was strengthening the muscles and fortifying the foot and fortifying above because remember your glutes help I mean the gluteal muscles are important for unloading the foot as well you know they they they take a load as well so he wasn't using his gluteal so it was more complicated than just his foot but that's an example I think plantar fasciitis in general that there are other causes of plantar fasciitis most of the time it's associated with weak feet and if you strengthen the feet then you don't put the load on the plantar fascia it's your first line of defense those muscles it's one of my favorite things to treat because it's it's I don't think it's hard it can take some time in patience for sure but I don't think it's hard it's fascinating right because I think I mean ultimately you can speak to this but I know in clinic it's one of the worst things to treat for us because I mean we're not really thinking about barefoot shoes right we're thinking about rolling a ball or doing a steroid shot or you know whatever it might be so it's definitely something difficult that most people think and when they think plantar fasciitis they say what am I going to do here but yeah I mean giving it a try at least with barefoot shoes well Dr. Davis I know the research is still pretty young right in terms of what we know about barefoot shoes versus shot and this is not to say to the audience that barefoot shoes are a cure all right I mean we know that there are certain injuries that primarily happen with barefoot shoes such as the meditarsal stress fractures the Achilles and things like that but what is the current state of research around barefoot shoes as in what are we currently trying to solve for and what else do we really need to look at good question so one of the things that we know is a barefoot shoes strengthen the arch muscles every single study that's been done has shown them to increase either the size or the strength that they're using dynamometers or cross-sectional areas or volumes of the foot muscles especially the plantar intrinsic muscles so we know that the state of the art is we know minimal shoe strength in your feet well we don't know is what's the effect on bone and that's my next question is I want to look at people who have been in middle to start out with cross-sectional study looking individuals who have been in minimal shoes versus those who are habituated to traditional shoes and look not only at their foot muscles but also the strength of the bone because I believe if you have stronger muscles and they're pulling on a bone there's a whole wolf's law right that those bones are probably going to be stronger as well and so I think for me that's one of the next questions that I have and then you know what is the effect it's as I mentioned I think I mentioned earlier that's really hard to get NIH to fund this kind of work there's the tends to be conservative and minimal shoes are there's always you know reviewers that feel it's too risky but it'd be really interesting to know whether those people who are in or even if you do a prospective study where you take a group of people keep one group in the regular shoes and one group in minimal shoes and follow them for some period of time to see whether injuries because we don't have I think a really good handle yet I mean I've seen it clinically but I don't think we have good research that shows that minimal shoes result in lower injuries there was a study that came out from the same Brazilian group I mentioned before Balsaco's group where they did foot core exercises there wasn't minimal shoes foot core exercises and they had a significant reduction in injuries these were runners and those who did the foot core program so if you think these shoes actually help to strengthen the feet and that study you know sort of A equals B B equals C then A equals C sort of indirect but we still need more we need more research for sure but I don't know that it's going to be the research I'm a scientist and I want the research it's my it's my metric it's it's you know how I feel like I can make those arguments in a in a very solid valid way but I'm not sure more research is what's going to do it in terms of going back to the original question you asked about how do we get this out there I'm not so sure it's research I think it's more marketing I agree with that I think I think when we're talking about you know changing our practice right and we talk about this word evidence-based medicine evidence-based practice our phrase right I think in teaching in medical schools and things of that nature although we can go down different rabbit holes of what really dictates medical education and you know PT education all that stuff but I think with respect to that more research will be better and particularly with hard outcomes like injury right I was earlier on Instagram today and you know there's this famous I think carpractor but he's very you know context driven in terms of like we all phosphorylate over you know take doing the big three by stuma guilt right I made everybody who's listened to Peter T and we've talked about stuma guilt multiple times about his big three and how the importance of course ability and how that can help with back pain and stuff and then you know there's this whole field of pain science and it's like oh well maybe that doesn't really matter you know I'll give you a personal anecdote I shared this recently as I can't I had a medical student come in a second year and right now he's in his dedicated board prep time and so he's setting 14 hours a day hunts up in front of a computer with maybe I don't know four breaks and so he's coming in with some upper back pain and neck pain and so you know my trainees when they saw him they presented the case they came back they were like I'm like well what do you think it's going on it's like oh well you know he's got posture issues got some tightness and maybe he's got some arthritis and it's like he's 24 years old I don't think he has arthritis in the neck but you know great give me your differential keep going and so we're talking about all these things and then we go and we talk about it and you know mind you he had seen somebody before and they had given some chin talks and all these postural correction exercises to say called it my a facial pain and ultimately what it came down to and it was a teaching point for him and you know for even a humbling point for myself and I was like listen man we can sit here and we can talk about postural correction exercise all day but if you're spending 14 hours studying hunts over in front of a computer you know three rounds of five minutes of posture correction is not going to fix that problem unfortunately this is a tough time in life the next six months you've got to get your boards and you've got to do well and it's time to sucks and we just got to embrace the suck for a little bit and so I share that it's a talk about it you know like we need like important clinical outcomes and specifically with respect to not just like how that changes forces that we've talked about which has been shown but does that prevent injury and especially like if somebody's going to go and invest money into that and time into that with the training that we're talking about if you're going to spend I don't know 45 minutes a week and you don't have that to train to do this stuff like we want to see if it is a really gonna matter and so I'm excited about that that being said though I think the marketing in terms of having these conversations more and more that's critical particularly in today's day and age where like social media and marketing is intertwining to medical education getting the word out seems to be the best way to get the conversation going so we want to thank you for that thank you for coming here and educating us and you know I'm super excited to continue following I hope our paths cross sometime in the near future I know Darshan's going to be down in Tampa and your neck of the woods and I'm actually going to be in Orlando in two weeks at the A B conference I wish I could come out to Tampa and visit your lab that would be awesome but maybe somewhere I would love to let me take you up on that where can you know where can people follow more of your work you know aside from searching you in PubMed and stuff I know that at one point you were doing consultations when you're up at Spalding is that something you're still offering down in Tampa where people can go out and I'm hoping too we have not got the clinic up and running so I mentioned that we had the Spalding National Running Center I founded that at Harvard and we did see about a thousand patients through that clinic and I hope to develop to open a clinic we're just trying to get through some of the logistics of it but hopefully soon I'll be seeing patients because I really miss it it's been a couple of years now because I'm down there for two years and I have never stopped saying patients it's really what's made my research relevant and important and it's so rewarding I mean research is you really have to be patient it's delayed gratification but when you work with patients it can be such more much more immediate gratification just I really enjoy trying to subproblem solve and help them work through the issues so yes hopefully soon and you can find me on Twitter it's Irene S Davis on Twitter that's the only social media I have I've Facebook but it's really family awesome we're gonna be sure to link all that with reminds me I wanted to ask you the follow-up about your research interest in where you think that it's going with the respect to the stresses applied to the bone were you just to clarify for me is that you were thinking more of an effect in terms of how it's going to help bone remodeling locally or do you think that transmits up the chain and we're talking about just bone density overall well I haven't thought really up the chain because I think we need to understand them at the meditarsal level because that is the area where people get injured and I think it's because they don't have the strength of the muscles to support the meditarsals and the meditarsals get loaded but I think that you know by strengthening those muscles the muscles themselves strengthening and 10th putting tension on the bone may help to strengthen the bone as well so I think that's what I'm thinking I was thinking more from the meditarsal level at this point are the meditarsals the most common side for like running stress fractures and or is it tibia tibia and then and then meditarsals yeah cool yeah tibia and then meditarsals and I just I want to say you know we've talked around and about a little bit about lifestyle medicine I just want to put a shout out for the American College of Sports Medicine of which I am president it is an amazing organization and they are all about you know how do we keep people moving better all through their life I have a pointed presidential task force on youth fitness and I'm hoping that they're going to come up with recommendations I would love to see the year of the fit kid or something like that or have youth fitness month because again I think this goes back to that but there are a lot of people at ACSM there are you know move it really doing a lot of good work in this area awesome well doctor Davis I want to thank you as well like I said in the beginning it felt like Halloween and my pillowcase is filled with treats now and I know there's so much more we could have you know gone down as far as gate patterns and you know kinetic chain all that and we'll definitely link everything you mentioned the show notes as well as other resources that I can find to really illustrate what we talk by notes sometimes it can conceptually be tough but thank you so much for getting the shoe and really showing our audience so definitely head to YouTube if you're listening if you really want to understand the mechanics that we're talking about and with that the last question that we ask is how do we add the health back to health care so I think the most important thing is that we move and that we move throughout our life and that we keep moving we can't stop moving we need to incorporate movement and good movement throughout our day and throughout our life and I think that prevention is the other aspect of this I think we are trying to treat things and put band-aids on on on issues and if we could be better at prevention some of that is just movement but even just keeping tabs on people you know you you go to your dentist for your checkup I think that that I would say physical therapists should see their patients every six months for a musculoskeletal checkup and I think that would help again prevention to keep the health and health care awesome well dr. Davis thank you again this was an amazing primer and I know you're gracially accepting to do a part two here so we can definitely go into more specifics for things so thank you you're welcome and thank you for the invitation it's been a pleasure thanks so much for tuning into another episode if this conversation vibed with you please go ahead and leave a rating and review and share it with your loved ones and your friends spreading the word helps get this episode into the hands of others who may benefit from it I want to thank our team Harita Yapuri for social media Ethan Jew for video Zenev Lugmani for research and Sarah Khan for our upcoming newsletter and as our disclaimer always goes everything in this podcast is for educational purposes only it does not constitute the practice of medicine and we are not providing medical advice no physician patient relationship is formed and anything discussed in this podcast is not representative views of our employers we recommend that you seek the guidance of your personal physician regarding any specific health related issues we'll see you next week