Dr. Irene Davis’ Change of Heart from Orthotics to Natural Foot Movement
Dr. Irene Davis’ Change of Heart from Orthotics to Natural Foot Movement
– The MOVEMENT Movement with Steven Sashen Episode 132 with Irene Davis
Irene Davis is a Professor in the Department of Physical Medicine and Rehabilitation at Harvard Medical School. She is also the founding Director of the Spaulding National Running Center. Dr. Davis 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 musculoskeletal injury. She has pioneered the area of retraining faulty gait patterns in both walking and running. She has received funding from the Department of Defense, Army Research Office, and National Institutes of Health to support her research.
Dr. Davis has given over 300 lectures both nationally and internationally and authored over 110 publications. She is a Fellow and Past President of the American Society of Biomechanics. She is also a Fellow of the American College of Sports Medicine and a Catherine Worthingham Fellow of the American Physical Therapy Association.
Listen to this episode of The MOVEMENT Movement with Irene Davis about how she changed her mind about orthotics and switched to natural foot movement.
Here are some of the beneficial topics covered on this week’s show:
– Why actively standing is a good for people to participate in and how to do it.
– How prescribing footwear based on someone’s foot type doesn’t prevent injuries.
– Why footwear changes the way runners strike the ground.
– How it’s important to transition slowly to being barefoot or wearing minimalist shoes.
– Why shoe companies started adapting shoes to the wearer, and how that isn’t beneficial.
Connect with Irene:
Guest Contact Info
Twitter
@IreneSDavis
Connect with Steven:
Website
Xeroshoes.com
Twitter
@XeroShoes
Instagram
@xeroshoes
Facebook
facebook.com/xeroshoes
Episode Transcript
Steven Sashen:
How can someone who not only makes orthotics, basically, for a living, but teaches other people how to do that have a change of heart and become the preeminent expert in minimalist footwear and natural movement. You’re about to find out on today’s episode of the MOVEMENT Movement, the podcast for people who want to know the truth about what it takes to have a happy, healthy, strong body, starting with the feet first, since those are your foundation.
On this podcast, you know we get rid of the mythology, the propaganda, sometimes the outright lies that people tell you about what it takes to run, walk, dance, play, hike, whatever it is you’d like to do, enjoyably, and more effortlessly. I’m Steven Sashen. I’m your host for the MOVEMENT Movement podcast. I don’t know why I say that, you all know who I am. More importantly, if you like what we’re doing, you know the drill, subscribe, like, share, review, go to www.jointhe movementmovement.com to find out all the places where we are and all the places you can interact with us.
If you have any questions or suggestions or complaints or just want to share a poem or PayPal me some money, you can send that all to move at jointhemovementmovement.com. Let jump in. I want to introduce to you my dear friend, Irene Davis. Actually, it’s more fun to say Harvard’s Dr. Irene Davis. When I say that, I have to clarify or I have to add, you weren’t always at Harvard, you started out at my sister’s alma mater, University of Delaware, where she was a fighting blue hen, I think the only mascot less intimidating than the Montgomery County Community College slightly annoyed ferret. Right now, you are not at Harvard, you are doing something really wonderful. You’re vacationing. Thanks for taking the time to chat.
Irene Davis:
No worries. Happy to be here.
Steven Sashen:
How else would you like to introduce yourself? I hate introing people because it always sounds too ridiculous. If you’re on an elevator and someone says, what do you do, what do you tell them?
Irene Davis:
I tell them that I was first a physical therapist, and I’m always a physical therapist, but I’m also a biomechanist. If you put physical therapist to biomechanist together, I’m a clinical biomechanist. How’s that?
Steven Sashen:
Okay, that will work. That works.
Irene Davis:
How’s that an elevator speech?
Steven Sashen:
Yeah, that’s a good one. Actually, before we jump into things, I always like to start this podcast, since it’s about movement and about creating the whole … Well, the MOVEMENT Movement, is because we’re trying to make natural movement, the obvious better healthy choice the way natural food is. We always like to start with something movement, would you give anything you want to share with humans?
Irene Davis:
Sure. One of the things that I like to think about, this is called active standing. If you are standing, you can either stand very slouch to relax, which is what most people do, or you can actively stand. Once you start to actively stand, that starts to become your habitual standing pattern or posture. It’s something that you have to think about in the beginning, but then you eventually habitually adopt it. What active standing is, is you stand, obviously, you’re standing, your feet pointing straight ahead. The first thing that I think about is doming my feet.
For those people don’t know what doming is, you press your toes, you straighten your toes, stiffen your toes, press them down into the ground, and then pull the ball of your foot back towards your heel. You’re basically shortening your foot, sometimes called short foot exercise, and contracting those muscles of your arch to start there. Then you tuck your butt in a little bit to get a neutral pelvis, you tighten your abdominals, you pull your shoulders back a little bit, slide your head back a little bit, and then stand there. It’s a very different stand. If you take that stance and then relax everything, you’ll see the kind of your habitual stance posture. I want everybody to just start thinking about incorporating active stance into their day.
Steven Sashen:
I want to add the first instruction, take off your shoes.
Irene Davis:
Exactly.
Steven Sashen:
Yeah. I also want to add that, Irene, the framing that you have in the camera is in part, because since you are at the beach, it just looks like you’re doing this semi naked, which I think is awesome.
Irene Davis:
I know.
Steven Sashen:
No, which right now, you just framed it here, which is great. It’s a …
Irene Davis:
I have a dress.
Steven Sashen:
Proof that you’re not naked. That’s my kind of thing. I only have one question that I plan to ask you, and it’s one that I know the answer to because you and I talked about it before, but it’s one of my favorite stories. That is, what was your moment of awakening from being someone who was showing physical therapists how to pose people’s foot, put them in orthotics to what you’re doing now, which could not be more diametrically opposed to where that all began?
Irene Davis:
There wasn’t a moment, Steven, it was really an evolution of thought. I really encourage people to keep their minds open because sometimes the truth that you have today is not the truth you’re going to have in five years from now. The truth five years ago is not the truth of today. We have new information, we gain new perspectives. I think what happened is I had started doing my work in understanding impacts. I was looking at strike patterns, thinking that forefoot striking was the unicorn, only a small percentage of people do it, but understanding just the differences between rearfoot striking and forefoot striking, understanding also the relationship between the impacts that you have as a rearfoot striker, and different injuries.
That’s how I started my career, started out looking at impacts in tibial stress fractures, and then continued into other injuries like plantar fasciitis and patellofemoral pain syndrome, some of the common injuries that runners sustain. Then also, this is at the time, it was at the time that Born to Run came out and Chris McDougall came to visit our lab. I didn’t know he was writing a book at the time. This was before Born to Run came out.
He wanted me to look at his ground reaction forces when he ran barefoot and with shoes, and start to make me think about barefoot running and what … An article had come up, oh gosh, I think in the ’80s and looking at barefoot running, but I never really paid much attention to it. Then when we started talking about this and he’d been down with the time of Omata, he was talking about how these individuals tend to run on the ball of their feet. Now I’m thinking, okay, I did this work in forefoot striking. Forefoot striking has less impacts.
Barefoot runners typically run forefoot striking and less impact seem to be less injurious. Then I connected with Dan Lieberman and he gave me an evolutionary biologist’s perspective, which was new for me and I started thinking about that. Maybe this is really the way where you’re adapted to run. It really was a slow process. Honestly, probably over the course of five years, three to five years …
Steven Sashen:
Wow.
Irene Davis:
… of thinking about it and coming to it. There was a study that came out in 2010, a series of studies by Joe Knapik, in which he was looking at different shoes and looking at the motion control shoe, the cushioning shoe, and questioning whether these shoes actually prevent injury. What he did is he took half his recruits and he did this in the army, the marines, and maybe the Air Force, and they combined it all in one big meta-analysis. There was something like 8000 altogether. Half of them were prescribed a shoe based on their foot type.
If they had high arch rigid foot, they got the cushion shoe. If they had a flat, hypermobile foot, they got the motion control shoe. Then if they had a neutral foot, they got the neutral shoe. Then the other half all got the neutral shoe. What he did is he followed them for … Not exactly sure how long, I can’t remember how long, but maybe through their recruit training, and found that there was no difference in injuries between those who were prescribed footwear based on their foot type.
That made me question, because I was teaching scores of physical therapists, this sort of approach to footwear. After seeing that, I thought, there’s 8000 subjects in the study, we’re still not finding anything, maybe we should question this paradigm, maybe everyone should be in neutral shoes. That was my first thought about footwear. Then when I started looking at how footwear affects foot strike, it started making me question even neutral footwear, because footwear, basically, if you put a hunk of rubber underneath the heel, people are going to land on it.
Steven Sashen:
Wait. Just so you know, I’m making notes, because there’s a couple things you brought up that I definitely want to bring up. Okay, keep going.
Irene Davis:
Alright. If you put a hunk of rubber underneath the heel, people are going to land on that heel. Why is it a good question? I think, in part, if you land on your heels, people tend to stride out for getting things. You can go faster, in a sense. I mean, there’s a payoff for that, but there’s also cost. That’s what made me start to question footwear. Then footwear and foot strike, maybe we can go into that maybe a little bit later. There’s definitely an interaction between this two.
Steven Sashen:
It’s funny you say that, because … You and I, last year, were at the American College of Sports Medicine’s annual conference, and both the guys from Brooks and Adidas started their presentation by let’s use the phrase in quotes quoting, Benno Nigg, researcher from Canada by saying that everyone has a preferred movement pattern and footwear doesn’t matter. I was biting my tongue because there was not an opportunity for me to counter that.
What I think I might have said is I was in the lab with Bill Sands, former head of biomechanics for US Olympic Committee, where what he would do when he got in his lab is he would have you wear your favorite pair of shoes, and then go barefoot and then try on every other pair of shoes that you brought in with you and film you on his giant treadmill that you’d go up to about 30 miles an hour at 500 frames a second. What he saw was the exact opposite that every different shoe you wore changed your gait, unless you were a super, super elite athlete, where you could pretty much put cinder blocks on their feet and nothing changed. I was amazed that they started with that idea that footwear didn’t matter.
Irene Davis:
Yeah, and footwear matters a lot.
Steven Sashen:
Well, and then similarly, I actually … It seems like one of my … I was going to say jobs or goals, I’m not sure what it is, is to annoy the CEOs of major footwear brands. I had a conversation with the CEO from Brooks, who they have their run signature program, where they put little dots around your knees and watch you squat and then have you run in socks. This is an important thing. They don’t want you to think you can do this barefoot, in socks on a treadmill, and then they somehow come up with some conclusion about which Brook shoe you’re supposed to wear. I just asked Jim the simple question, “Well, where’s the evidence that that improves performance or reduces injury?” That was the end of the conversation.
Irene Davis:
There is none. I wanted to pick up on your comment about how footwear doesn’t matter. Not that you think that, but the other people think that. You know what made me really, really believe that, is when I came up to found the Spaulding National Running Center, we’ve now seen over 700 patients. Every single patient has come through our center. I watched them in slow motion, run, close up of their foot, run backside, it barefoot, in their shoes, which 95% are in traditional shoes, and in a pair of minimalist shoes. What I see is what really convinced me that footwear really matters. I mean, the changes, it’s not always. I mean, the change …
Steven Sashen:
No, but significant.
Irene Davis:
Significantly in the majority of people, footwear changes the way they structure.
Steven Sashen:
Yeah. Well, when I was in Bill’s lab, we did a little pilot study because we were … What he saw when I was running just in our original sandal, which was just piece of rubber strap to your foot, which we still sell. He noticed that my running was basically the same when I was in those compared to when I was barefoot. We did a little pilot study. We brought in people and we had them run either … Well, all four of these conditions, barefoot, in a pair of sandals that I made for them, and a pair of five fingers because we got people who all own five … Actually no.
We even brought some. I don’t think people own them, or in whatever their regular shoe was. I don’t know why that’s four. That’s a weird way to do four. There we go. What we saw was two things that were really interesting. Actually, three. One was that, like you said, almost everybody, when they switch to barefoot or in our sandals, gait change in really, really positive ways for about 90% of the people, and was very consistent. The second thing was that when some people who were accomplished barefoot runners, when they’re running barefoot, they look great.
When they put on the five fingers, let alone their minimalist shoes, they often started overstriding and heel striking. Here’s the kicker, they didn’t know they were doing it. That was because they were wearing one of those shoes that had more padding than the others because they were made for running, big air quotes. Then what was the … The third thing was the people who didn’t have an automatic gait change in some way to something where … When I say better, what I mean was getting their feet underneath their center of mass, landing forefoot or midfoot in that case, just not pawing at the ground.
Just things that are seemingly obvious at this point. That time, this is 2010-ish, we’re radical. It took very, very simple cues to get them to do something different, where they suddenly felt better. It was just giving them the idea that they could do something different instead of trying to run the same way, and they did. It was really spectacular to see. What crack me up, of course, is how surprised everybody else was.
Irene Davis:
Yeah. Yeah. You mentioned midfoot striking, and it is something I want to bring up because …
Steven Sashen:
I knew you would.
Irene Davis:
Yeah. I mean, it’s like partial minimalist shoes, minimalist shoes, and traditional shoes. A lot …
Steven Sashen:
Hold on. Wait. I’m going to pause you there, because this is something … I don’t know if you know that I do this. I know you break things down into traditional shoes, partial minimalist shoes. I’m going to ask you to define that versus minimalist. I say that when you say that you’re just being politically correct, and I redefine it as minimalist, fake minimalist, and normal.
Irene Davis:
Okay. I’ll buy that. These studies have been done in the partial minimalist shoe show that people run pretty similar when they run in traditional shoes. It’s not until you get to true minimalist shoes that you really start to see the changes, and so this idea. I used to think in the beginning that, well, this is a nice compromise. People like compromise. They don’t like to be on the edge. They like to be in the middle.
Steven Sashen:
People do like to find something in the middle. Part of that is when the whole minimalist thing kicked in, the first response from the big shoe companies was don’t do this, you’re going to kill yourself and you’re going to get Ebola and you’re going to step on hypodermic needles and the turtles will die and dolphins will come beaching into your house, whatever it was. Then by the end of 2010, they’re all coming out with partial minimalist shoes and saying that those products gave you the same benefits as being barefoot, not even compared to other real minimalist products.
Steven Sashen:
Then the companies that weren’t willing to go there, I mean, Adidas is the one that pops into my mind, first and foremost, like, oh, here’s a whole transition program. Go from here to here to here to lower, lower, lower. Everyone’s going, well, yeah, that makes sense. Unless you think about it, when it makes no sense. The idea of partial minimalist is definitely or fake minimalist is definitely catering to people thinking that maybe I can’t make such a radical change right away, which is ludicrous.
Irene Davis:
Well, I mean, you can’t make a radical change right away. I don’t think that’s ludicrous. I think you do need to gradually transition.
Steven Sashen:
Yes, that doesn’t mean you have to gradually drop the height of your shoes. You have to make a gradual transition to your movement, but not …
Irene Davis:
Because you don’t really need the changes until you’re in a minimalist shoe. What we do, obviously, we do try to transition people really slowly. That means the dosage that you get as well as building the capacity, because it does load your body differently. It loads the calf differently. It loads the arch differently. I do think it’s smart to transition, but we don’t do it that way. We don’t go from affect, we do the other way. I started the conversation with talking about midfoot strike.
Steven Sashen:
Midfoot and forefoot, yeah.
Irene Davis:
That was another compromise that I always thought was the way to go. I, actually, before really studying it, said, okay, midfoot striking is a nice compromise. You don’t have to work on your calf so much. It doesn’t load the calf most, but you don’t get the impacts. Well, once we started looking at our data, and we have data from the ground reaction force data as well as tibial shock. What we found is that when you look at tibial shock or load rates, which are an indication of … We’ve shown to be related to injury. It’s how fast your body is being loaded.
They tend to be higher in rearfoot strikers who have an impact beat. Those load rates are actually not statistically different between rearfoot and midfoot strikers. Midfoot strikers look like they’re a little bit odd, but they’re not at all significantly different. The same with tibial shock. They’re similar to rearfoot strikers. These are people who habitual midfoot strikers and this is what I think we have to do, is we have to study people in their habitual states, taking someone and making them a forefoot or a mid-foot striker or whatever. Taking a forefoot maybe is not going to be their habitual state and gait are not as valid.
Steven Sashen:
This is an argument that I’ve had with Roger Kram here at CU where he takes people and has them switch to something barefooting shows, hey, their VO2 max is worse. It’s like, well, yeah, they’re doing something brand new they don’t know how to do it. How is this some anyway?
Irene Davis:
I love Roger. Love him. I think he’s awesome. I’ve had that same conversation with him. He’s done the stride length and the oxygen consumption. I’ve asked him that question too. Once somebody is accommodated …
Steven Sashen:
It’s different.
Irene Davis:
… with stride, then that might be their U makeshift. You know that.
Steven Sashen:
Well, I similarly like Roger very much. We see each other at track meets every summer. I made that comment and I’ve also said, “Look, when you’re studying barefoot compared to whatever, you’re bringing in people that you’re calling accomplished barefoot runners. I know all the barefoot runners in town. I’m one of those barefoot runners in town, and nobody that I know has been in your lab for those studies. I don’t know who you’re studying.” I mean, I suspect I know who he’s studying, and it’s people who do some training on grass in bare feet, which is just not the same.
Irene Davis:
It’s not the same, yeah.
Steven Sashen:
And …
Irene Davis:
Then you run them on a hard treadmill.
Steven Sashen:
One of his studies was actually he took a treadmill where he put 10 millimeters of foam that he had gotten from Nike on it. Which was interesting, of course, that no Nike shoe has 10 millimeters of foam, for one. The other was, again, it was … I don’t know what it was. The whole reason for doing that or one of the reasons for doing that was looking at VO2 max as an analog for performance or as an analog for efficiency. I thought that was an interesting bit of hand waving because no one in the barefoot world ever claimed that if you run in bare feet, it’s more energetically efficient.
Of course, nor is there any correlation between VO2 maximum performance. Because if there was, we were to see who had the biggest VO2 max that day and give them a trophy. There’s ways around that. I thought that was very interesting. Look, I’m not trying to throw Roger under the bus when I say this, but over a beer, I said to him, “We know that studies or the meta-analysis of studies of pharmaceutical drugs show that if the pharmaceutical company is paying for the study, the results tend to air in their favor more often than if it’s an independent study.” I said, “Your lab is Nike sponsored. Don’t you think there’s anything in there that might be problematic?” I’m not surprised that he said no. I don’t know that there is, but it gives me some pause.
Irene Davis:
Yeah, it’s hard. Because when someone wants to fund your lab, that it. It gives an apparent conflict of interest. I mean, I trust Roger. I think he’s a lot of integrity. I find it difficult. I’ve tried not to take footwear money for that reason, unless I offer. For example, our Boston Marathon study, we went to every footwear company, everyone, and the only people that were willing to support it … I mean, the study wasn’t about footwear, it’s about running outside. It was Vibram. Vibram did support one of the studies. We offered it to Adidas.
We offered it to everybody. We went to all of them. In that case, it’s a little bit different, but it is hard. I mean, I understand why people do it. I mean, Joe Hammel has had a lot of commercial support as well, as well as Benno Nigg, and all of those folks. It does give at least apparent.
Steven Sashen:
Yeah. I mean, we’re concerned about that from our side, Lena, in particular, really wants to fund some studies, assuming we have the cash to do that, which right now, all our cash is going in the inventory. It’s something that if we raise some extra capital, she wants to fund some studies. I said, it’s inherently problematic, because people are totally going to say, well, of course, it showed that whatever you’re doing is better because you put up the money. It’s funny, backing up to the ACSM thing, this is something I quote often. I don’t remember.
I think it was the guys from ATI who said, well, we say that we’re all about reducing injury and improving performance, we don’t have any studies to show that. Because doing that would be very time consuming, it take a long time, cost a lot of money, have a lot of confounds that would make the results suspect. Again, it wasn’t my position to say anything, but my thought was, dude, if you could make a shoe demonstrably scientifically better than the guy sitting next to you, and that was the guy from Brooks, that’s worth billions of dollars a year.
You’re saying you haven’t done it because it’s difficult? I mean, I’ve heard rumors of studies that have been done internally from larger companies where it did not prove what they wanted to prove and those studies have not seen the light of day. I mean, it couldn’t be more clear that if a shoe was significantly demonstrably better, people would be shouting that from the rooftops. There could not be more incentive for a lot of companies to have done that over the last 50 years, and no one ever has, and in large part, because they’re just reinventing the same broken wheel.
I was just at ISPO, this big tradeshow in Germany, and I said somewhat apolitically, that because I lost the urge to be politically correct or diplomatic, I said, “If you walk around this hall and just swap the logos for most of the shoes, you wouldn’t be able to tell. There’s maybe one or two brands where it would make a difference.” Even then, you’d go, oh, okay, looks the same. It’s shocking. Actually, I thought of one other thing that I want you to talk about from a previous conversation of ours.
Early on, when we first started chatting, one of the things you said to me, which was very striking, and frankly, both inspiring and sad at the same time, and also riled me up, you’ll see where I’m going with this as soon as I tell you what it is, was that one of your big hopes was that before you die, people understand the impact of what you’ve been discovering and researching and studying and sharing with people. I’m really curious what your thoughts are about why it has been … First of all, why it is that we, in the natural movement space, need to prove anything?
Because we’re not the intervention, the intervention is what’s been happening for the last 50 years. Then why it’s so shockingly difficult to get people to hear it, understand it, try it, experience it, et cetera, when it is so screamingly obvious?
Irene Davis:
Yeah. I don’t think I exactly said what you said.
Steven Sashen:
Okay, well, that’s the way I’m telling it.
Irene Davis:
I don’t want my work before I die. I guess what I really want to see is for us to revert back to allowing the feet to function more naturally in kids, and then it becomes the norm.
Steven Sashen:
That was part of it. Now part of the other thing that you said in that same conversation, to the best extent of my memory, which I’m never claiming is accurate was, yeah, if we could just get kids to be doing this now in 20 years, we wouldn’t be treating adults for all the problems they have right now.
Irene Davis:
There would be conversation, right? I would be very interested to know what the injury patterns would be like. We all can say what we think and we can hypothesize, but we don’t know. I did a search on the term running injury, a Medline search from 1900 to 2000, just to see for the last 100 years, there was nothing in the literature. Now I’m not saying there wasn’t one study that didn’t have running injury in its title, but there was not one study with running injury in its title until 1977, not one. Then afterwards, there are thousands and thousands of them now from 1977 to present.
Steven Sashen:
When did Jim Fixx’s book come out?
Irene Davis:
’80? Was that ’80?
Steven Sashen:
I think I was in high school. I graduated in ’80. It looks late ’70s. Probably somewhere right around them, but certainly ’77 is definitely not the time in which the running boom kicked off. That predates that, but that’s really interesting.
Irene Davis:
It’s very interesting. What that tells me, so the very first running injury report that I could find was 1971, a newly minted runner’s world put out a survey to its readership and asked about injuries. They found that the people who reported injuries … I mean, of the people that replied, I think it was something like 20 something percent had gotten the … I used injuries as an example. Then they repeated it in ’73, that 800 runners in ’71, and then ’73, they did two years later and they had 1600 runners, and then the knee injuries increased. You could start to see that things were increasing just from that early injury study, but that wasn’t published. That was something that was in runner’s, the first published article.
Steven Sashen:
Got it.
Irene Davis:
You have to think that if injuries were happening a lot, that they’d be in the medical literature. I mean, medical literature has been around for a very long time. People have been running marathons for very long time. Now, I don’t think you can disassociate though, the running boom with the footwear change. I think they go together. There is ought to be a relationship there. More people were running who were less fit, but they weren’t as unfit as we are today.
Steven Sashen:
No. Because, look, the people … I mean, yes, it was a boom, but it wasn’t like the boom happened on day one and suddenly, everybody started running regardless of their state of physical fitness. I mean, the first people to adapt it were the people who already hipped to the idea, to begin with. You didn’t start seeing really overweight people getting into marathons till for a while.
Irene Davis:
But it’s interesting. Because what happened is you have people who are not used to running, running in flats. This comes from talking with Jeff Johnson, who was one of the early … He worked with Nike very early on. He actually came up with the Nike name, I believe. I had a conversation with him. He doesn’t have email. I think he has one of those phones on the wall with a curly cord, you can get the sense of it. He told me about how they were … He was running in the ’50s in plimsoll shoes, like just a rubber sole and canvas to keep on top.
He said they had very few injuries, very, very anecdotal. He said, what happened is, when other people started running, so people who were not used to running and they were getting these reports from the sports podiatrist that they’re having these injuries and they brought three very well-known sports podiatrist in, that is Pixie, Steve Subotnick, and Harry Hlavac, I think. Anyway, they came in, they said, “Look, we think that they’re getting injuries from hitting too hard, not enough cushioning and too much motion.
Also, because they were used to walking in shoes, typical walking shoes had two-inch heels. Now they’re putting a strain on their Achilles.” What they did is rather than have runners adapt to the shoe and the footwear that all the other runners were running in, which were basically minimal, they started adapting the shoe to the person.
Steven Sashen:
Or to this idea.
Irene Davis:
To this idea that did to the … Right, that you need to give them that relief in the Achilles tendon, so now you get an elevated heel, give them cushioning because that’s a problem. Because they hadn’t learned how to attenuate their low jet, give them motion control. Well, what happened is the very adaptations that they made, actually, I believe, have further creative problems in one of those cycles.
Steven Sashen:
Well, A, I agree. B, you and I have another mutual friend, Mike Friton, who says he was at a track meet. I don’t remember with how many of those three guys, and said, “So your idea has become ubiquitous, and this is footwear design now. What do you think?” The response was, “Biggest mistake we ever made.”
Irene Davis:
Wow.
Steven Sashen:
I mean, but the whole thing about heel strike, to begin with, or why it happens, it’s funny. Not funny. If you look at the videos that Lieberman brought back from Africa with habitual barefoot runners and you look at their foot strike pattern. I mean, their heel is like so close to the ground as it’s coming through the swing phase. Then at touchdown, it’s barely off the ground. If you just throw something that’s more than a half an inch on their heel, they’re going to hit their heel in front of their body, because they are not unlike anyone else.
They’re not going to just change their movement patterns immediately. If they don’t change their movement pattern right away, they’re going to land on the heel. Then they have that padding. Of course, calcaneus heel bone is a ball, so that’s unstable. Now you need motion control. If you’re landing with your foot, by the time your foot comes down, if it’s totally flat, your plantar fascia are in this weak position. If you’re going to do anything to deal with that, you’re going to put in “arch support” so you don’t maybe your arches.
Put it all together and now you have something where you’re preventing all sorts of everything, not letting the foot function in any way. What a shock that we’re having problems. I mean, it seems like this obvious evolution of errors.
Irene Davis:
Yeah. That’s why it’s hard for me to understand why people are so dug in. I mean, I know there’s financial investment.
Steven Sashen:
I think some of it is similar. I’m going to segue into something funny. I got two notes of things that I want today. The first one, I have to tell the story this way or I have to set it up this way, or it’s just too offensive. About 10, 15 years ago, one of my best friends calls me and he says, “You know what your biggest problem is?” I said, “Ooh, this will be fun.” He says, “Your biggest problem is that you just tell people if they’re factually incorrect or logically inconsistent or in some cognitive bias or anything like that, where they’re not thinking clearly.
You do that, because you find it interesting when people do that to you, and you think they’re going to find it interesting and go, oh. Mostly, they just think you’re an asshole.” I said, “Oh my God, I’ve literally never put it together like that before.” He said, “See, you just did it.” Which is true. In a similar vein, I’m going to say I have a theory about what your biggest problem is. Your biggest problem, and it’s not that it’s your biggest problem, but I think this is an answer to the question of why it’s so hard, is that human beings, when they come to a decision, think they’ve done it rationally.
They think it makes sense. Especially with all the marketing behind the footwear we’re talking about, they get a lot of evidence for that, despite the fact that that footwear hasn’t worked for them and they keep changing it over and over and over. The story keeps changing over and over and over. I’ve referred to this as the boy who cried or the shoe company that cried wolf. The only difference being that we keep showing up to see if there’s a wolf, despite the fact that there never has been for 50 years.
Because they’ve made this rational decision, it’s also energy inefficient, evolutionarily, and energy inefficient to make up new ideas, to come up with alternatives and counterfactuals to what you already believe. What you’re often doing brilliantly, I believe, is presenting more rational information. There’s a lot of psychological literature showing that when you present someone with information that conflicts with their existing belief, it actually makes them dig in harder. Because that’s the way we’re wired.
It makes me wonder, what’s the way around that? Certainly, my experience has been that experience is one way around that. I think there’s got to be another way to encourage people to have the experience to begin with, it’s beyond giving them all the data that shows that what they’re currently doing isn’t going to give them what they want. I mean, how many studies have there been showing that highly cushion max seamless shoes don’t reduce impact loading forces.
Yet people still buy them thinking that it’s going to be cushy and make them feel better and be better for their knees, when we don’t see that. I think this is the conundrum that you may find yourself in, is that you are both creating and discovering and inspiring all of this information, but information isn’t going to be the thing that makes the change.
Irene Davis:
Yeah. I mean, I’m wired that way, the …
Steven Sashen:
You and me, both.
Irene Davis:
Evidence is my coin. It’s my metric. I keep thinking that if we can demonstrate that, like when people run in minimalist shoes, it’s been shown that the Achilles is stronger and stiffer. It’s been shown that muscles are stronger. Stronger feet are going to be healthier for you. It makes sense to me, but I think …
Steven Sashen:
Irene, don’t I need arch support?
Irene Davis:
Yeah, I know.
Steven Sashen:
I mean, seriously, don’t you get that as the follow-up like, but don’t I need …
Irene Davis:
One of the arguments I get, which is maybe not a bad argument, is that having some padding in their shoes allows them to run farther. There may be some truth to this.
Steven Sashen:
I’m not going to argue that one. Because especially with ultra-runners, where by the time they’re in the last part of the race, their form has degraded to complete crap and they just need to do something to get through the rest of the race. I’m all for it. For the average recreational runner, it’s like just do a mile less and be healthy.
Irene Davis:
This is it. It’s because people … I always tell them, you’re out running your capacity. Your body has the capacity to cushion and to control your steps. If you want to run farther than your body has the capacity for, then maybe you need that crutch, so to speak. You know what I mean? I mean, there is a tradeoff, I think, in terms of that. If people choose to do that, fine with it. I’m trying to promote it. If we got people and kids in minimalist shoes and that’s all they ever wore, they would have built over the years the capacity to be able to run longer distances.
Plenty of people run marathons in minimalist shoes or barefoot, but not all people can. That’s the argument that I get. I say to them, “Look, if you want to run a marathon and you don’t have the capacity to do it in minimalist shoes, then you probably shouldn’t.”
Steven Sashen:
It’s funny. When I was in Germany, one of the guys that I was on the panel with was from New Zealand. I brought up Arthur Lydiard, who for people who don’t know, was the coach of New Zealand runners. He was probably the most successful coach in history, especially if you think about the population he was working with, this tiny little country, and the number of world champions and Olympic medalists that he produced. There are a number of things that were interesting.
One is Arthur had people doing tons and tons of mountain hill training in the shoes that he made for them, which were super thin soled. They look like mine, frankly. Even this guy from New Zealand who is now repping for a company that makes big, thick padded shoes, was saying, “Oh yeah, that’s what he did and it was great. He believed that having foot strength is really important.” He’s saying this while wearing a shoe that does the exact opposite of what Lydiard did while talking about how great Lydiard’s methods were.
I heard a story that Lydiard and Bill Bowerman from Nike had this knockdown drag out argument about shoe design after Nike started doing the elevated heels and padding, and Lydiard just saying, “You’re just going to kill people.” Bill Bowerman saying, “Yeah, but they’re selling really well.” It is interesting, related to the phenomenon of people outrunning their capacity is … Wait, where did that thought go? Oh, it’s people using elite athletes as the example of what they should do. I keep saying, you’re not 105-pound Kenyan guy who runs a marathon into a five.
You’re a 200-pound whatever guy who runs a 430. To think that what he’s doing on his feet is what you should be doing, what you should be wearing is ridiculous. Of course, the other issue is that, I mean, so much changes when you’re running at speed. People talk about, well, we’ve analyzed all this video data. Look, this guy is heel is touching the ground first when he runs like, yeah, yeah, yeah, but he’s running at basically 13 miles an hour. By the time he actually loads his foot, it’s a whole different story. Yes, his heel is barely touching the ground before it gets any loading.
Again, just like you said, people want a simple story. Ironically, I think we have the simplest story, your feet are supposed to bend and move and flex and feel the world, and that’s what you should be doing.
Irene Davis:
Right, I know. The other thing I think we have to remember too, is that if you follow this whole mismatch theory of evolution and you believe that we should move the way we’re adapted to move, we really weren’t adapted, I don’t believe, to run 26 miles relatively on a straight path on hard surfaces only. I mean, I think we were adapted to run on hard surfaces, soft surfaces, variable surfaces. We’re running back then what we were adapted for, was really stop and go, changing directions, that kind of thing. Maybe we’re setting ourselves up in that way for injury and maybe people need that footwear to be able to do that kind of running.
Steven Sashen:
That’s interesting. What’s intriguing to me about that is thinking about the fastest growing movement in running right now, is trail running. I think that that may be because it just does have that more …
Irene Davis:
Variability.
Steven Sashen:
Yeah, that is helpful and feels good and is interesting and compelling and …
Irene Davis:
Injurious.
Steven Sashen:
Yeah, yeah, yeah. What’s so funny, I went for a run up one of the mountains outside of Boulder with a woman a couple years ago, who I was in a pair of sandals, and she was doing it barefoot, barefoot. Because she’d spent a lot of time practicing and got really good, not about what people think, is that she has some massive calluses under her foot. She just got really good at mapping the terrain and running with the terrain. People looked at us like we were the crazy ones. We were the ones that had this insane look on our face called smiling.
It’s fascinating. Here’s another question that just popped into my head, backing up to after you do your elevator pitch, I’m imagining that I’m not the only one who, when I tell people what I’m doing, they bring up the Vibram lawsuit and as seemingly proof that this whole idea is ridiculous. How do you respond when people toss that one in your direction? I love that look.
Irene Davis:
Good question. The first thing I tell them is that the Vibram lawsuit was not about injury, but it was about false advertising. Because Vibram talked about how it strengthens your feet. There had been a study with the Nike Free, showing that when you take away arch support, the arch muscles got bigger. They were, I think, piggybacking on that thinking that it would. That’s what they were sued on. That’s the first thing I tell people. The other thing I tell people is, if you went to the gym and lifted 100 pounds, the very first time you got injured, do you think anyone would say don’t ever go to the gym again?
Or would they say don’t do it that way? That’s exactly what’s happening. You can’t just take and put a pair of shoes on that now puts a greater demand on your foot, the medial lower leg, the posterior lower leg. Primarily, those are the areas that get loaded the most. Run your regular mileage and think that you’re going to be able to do that. It’s like going out and playing seven flights of tennis when you’ve never played. You’re going to injure yourself. You’re going to be really sore, or at worst, you can injure yourself.
Steven Sashen:
Right. Yeah, I also add that the lawsuit was settled out of court, which means and for pennies on the dollar, and I think that … I’ve had this conversation with Tony Post who was no longer CEO of Vibram at the time. Tony says he wouldn’t have settled the case because of that Nike Free study. I think there were some other dots that they connected.
Irene Davis:
I think they had shown that a shoe that does not have arch support results in … Now they’ve been many more studies that have actually supported that. It was unfortunate, but it wasn’t about injury.
Steven Sashen:
Yeah. Well, and backing up to what you just said about many studies and what I said earlier about the American College of Sports Medicine thing, so the guys from Brooks and Adidas, they both misquote Benno Nigg. Actually, I don’t know if I told you this. I had a talk with Benno’s son, Sandro. I was about to read him the riot act about this idea of preferred movement pattern and how it’s just not the case what I’ve seen in the lab and what I see with the people who wear Xero shoes.
Before I could finish the sentence, he said, “Oh, what my dad was saying is that you have a preferred movement pattern that’s difficult to change, assuming you’re basically wearing the same kinds of shoes, which every shoe is basically the same kind of shoe. He never said that if you switch to something truly minimalist or barefoot, that your gait is going to be the same. It’s definitely going to change right away.” It’s like, there we go. Completely taken out of context.
The reason that I bring that up, is that when these guys said, we don’t have a whole lot of research to back up what we’re claiming, I had a slide that was just little brief screenshots from, I think, 40 different minimalist studies that I just found by searching on PubMed for minimalist shoes, and just one after another showing the benefits thereof. Or the simple thing, it amazes me that we need to pull out studies that show if you use your feet, they get stronger, if you don’t use them, they get weaker.
Irene Davis:
That’s the part that seems so simple to me. I just think you’re right. I think that they get stuck in their dogma, they really do. It’s like it’s the way that they think and it’s hard to think differently. That’s why I try to tell young scientists to keep your mind open, because I was the person that made every orthotic in … When I was at the University of Delaware, I was a person who was in the clinic doing foot orthotics. I taught it in the curriculum. I taught people motion control, cushioning. I taught all that. I believed it. When I started to think a little bit differently and I start putting things together and reading different things, it made me think differently. You’ve got to be open to new ideas.
Steven Sashen:
Well, I want to back up to the first part of that. How did you learn those things to begin with?
Irene Davis:
From someone else who taught me, who was basically … It was actually someone that I worked with and did my PhD with, who was really very much a foot person came from a really strong hospital that worked on feet. It was more diabetic feet, but had done a lot with orthotics. It’s what you’re taught. I was taught some of it in school, I think. It was from my peers and what I was taught in school. I think you get that mindset. That’s why it’s important that we get this back into the schools and program.
Steven Sashen:
Again, I want to follow it back in time. They learned it from someone. The question is, when? Because what I … I don’t know if this is true, but there’s two types. One just for footwear in general, we know that … Let’s call it the modern athletic shoe, is a relatively new phenomenon. Now it’s been 50 years. We’re past two generations. Parents are teaching this to their kids before they ever even walk into a shoe store. The shoe companies don’t need to do any of the heavy lifting anymore. They can just say, hey, don’t you want to be like this guy? They don’t need to justify any of their designs, although they try to.
Irene Davis:
They do. They have them run in the shoe store with really very little experience. They’ll have you running and you can pull out a shoe. I think that’s where it’s coming from. A lot of is coming from the running shoe stores and marketing.
Steven Sashen:
Well, yeah. I don’t know about the history of orthosis, but my hunch is that whoever came up with the idea of putting an orthotic in a shoe and posting in the media large and doing whatever else they need to do, especially for runners, then realize that this is a way for practitioners to make a bunch of cash and created, basically, a marketing plan. That once that initial push was done, the rest of it just rolled. If people look back and found that initial event and saw that one, that might be a way of snapping people out of a bit of a 50-year-old trance, or maybe not.
I mean, I sometimes half-jokingly say, it’s a shame that footwear doesn’t kill people. Because if shoes killed people, then we’d have tobacco situation on our hands, where there’d be a lot of incentive to do something about it. It’s like, yeah, it’s shoes.
Irene Davis:
Yeah, it’s interesting. I do think there’s been a change in the podiatric world, because I hear more and more podiatrists say, these shouldn’t be permanent. To me, that’s a huge win.
Steven Sashen:
That’s a big change.
Irene Davis:
Huge win. I made orthotics for three different pairs of people’s shoes. You need them in all of them. Honestly, it was not for money at all. Because as a PT, we never charged the same as a podiatrist did. We didn’t make a lot of money. I really believed it. I’m going to take the higher road, I mean, a higher road, but I like to see the good in people. I think a lot of the podiatrist that I know really believe that these really help. In …
Steven Sashen:
No. I agree with that completely. I don’t think that anyone’s doing it explicitly for the money. I think that they are doing it because they believe that it’s useful. The money doesn’t hurt. The money locks in that belief. It’s like I remember when I first got back into sprinting 12 years ago or so, I went to someone because of some problem I was having. He suggested that I wear an orthotic. I said, “But I’m a sprinter. You’re going to put me in a three-quarter orthotic, I’m never on that part of my foot. How is that ever going to apply any forces to change anything?”
You watch this guy’s brain explode. I mean, he spent like five minutes trying to figure out tell me why it would still be useful. Then he realized he was at the end of his rope and had nowhere to go. That was a real … This was before I knew any of this. It seemed really obvious that I was going to be on my toes and the orthotic did not go to my toes. That was a funny one.
Irene Davis:
That is put to your metatarsal heads though. It is supporting your arch, so that when you land on the ball of your foot, you do bring your heel down and you do get some support from that orthotic, even as a forefoot striker.
Steven Sashen:
It’s interesting. I never felt that. There’s a company that makes up a somewhat concave or convex, depending on which way you’re looking at it, with carbon fiber insert that they say improves performance and you get more spring out and blah, blah, blah. I put it on. I ran with them. I tried a few of them. I don’t feel a thing. Because I’m never loading it in a way that it’s going to do whatever it’s supposed to do afterwards. Besides, it’s physics. You’re not going to get more energy out than you put into it. I mean, I literally didn’t feel a thing. I put one in one shoe and nothing in the other and switched them and I put in both. I did everything I could think of to see if I could feel anything and just got nowhere.
Irene Davis:
Yeah. I tell people, I think that it’s important to support the arch if you have some active plantar fasciitis. You support any body part when it’s injured. Then you need to slowly remove that so that you can get that strength back, just like you would with a back brace, a neck brace, a shoulder brace, any other brace.
Steven Sashen:
Or getting a cast off your arm. That’s the analogy I use. If your arms been in a cast, you take it out, it’s atrophied. You have two choices, keep it in a sling for the rest of your life or use it again, and then it’ll be fine. What are you taking a look at now? What’s coming up in the wonderful world of Irene Davis research?
Irene Davis:
Gosh, we have a lot of things going on. We’re just getting a study off the ground looking at basketball players and looking at how they land and looking at tibial shock in basketball players and how that changes throughout the game, throughout the season, how it relates to injury, how fatigue affects how they land, how sleep affects how they land. That’s a big one that we’ve got.
Steven Sashen:
We made a … Let’s call it a demo basketball shoe. I put it on a WNBA player who sent me two emails that were interesting. The first was I couldn’t sprain my ankle and knees if you paid me to. The second was there’s times where I come down from trying to block a shot or rebounding or something, and I’m landing on my heel. With nothing under my heel, that’s really a problem. We’re trying to find this interesting balance of giving them what they need for this specific use case without creating movement patterns that they believe and we believe are going to be not beneficial. It’s been an interesting thing, trying to work that out, especially without a giant budget where we can just make 100 pairs of shoes for her to try and for other people to try.
Irene Davis:
It leads me to another point. A lot of people ask me the question, okay, so minimalist shoes for running or for walking, but what about for other sports? Walking and running are things that we were adapted to do. We’re adapted to ski, for example. We weren’t adapted to ice skate and play hockey. In the things that we weren’t adapted to do, we sometimes have to have things that help us to do those activities that we’re going to have to do. If you don’t have a stiff ankle boot in skiing, it’s going to be very difficult. It might be the same with basketball.
Irene Davis:
Whereas walking and running, you can do those barefoot. You could argue though, I mean, there are people, there are countries that play soccer barefoot. When we go to Italy, the kids in the Piazza are playing on the concrete Piazza barefoot playing soccer at a young age. I think you probably could adapt to some of those things. That, of course, involves running, which is something we’re adapted to do.
Steven Sashen:
Well, yeah. There are just this specific situation that happened in some of these sports where you need to adapt to that in some way. Again, you don’t want to take that one adaptation or that one intervention and have that apply in such a way that it affects everything else and unnecessarily. I can’t wait to hear what happens with that. What else?
Irene Davis:
We are looking at differences between forefoot striking in minimalist shoes versus forefoot striking in traditional shoes.
Steven Sashen:
Ooh. I don’t know if we’ve talked about this one. This is something I started talking about recently, when I just started noticing that a couple of people running by me on the track who had good forefoot strike patterns, but they’re wearing shoes like this. They just don’t get any of that Achilles spring action going on. It’s like they’re limiting what their body can do for them. I don’t know. Have people been talking about that?
Irene Davis:
We weren’t looking at that. We published a study in MSSC a couple years back. Hannah Rice was the first author. We found that when you forefoot strike in a pair of minimalist shoes versus traditional … Well, it’s the other way around. When you heel strike in a pair of traditional shoes or forefoot strike in a pair of traditional shoes, your resultant load rate, that means the combination of vertical, anterior, posterior, and mediolateral is similar.
Steven Sashen:
Interesting.
Irene Davis:
The resultant load rate is the same. The reason for it is the vertical load rate is less forefoot strike in a pair of traditional shoes. The anterior, poster, and mediolateral
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