With decades of running experience and practical research in shock mechanics beginning at NASA Johnson Space Center, Zach has worked as a physicist in a wide variety of disciplines (some he can even talk about). For those who care he has degrees in Physics from Ga Tech and the University of Colorado at Boulder. He has taught computer science at CU Boulder and participated in running gait studies at CU. Zach has applied technology to speech recognition for doctors, aircraft stealth and cloaking, climate research, image processing, and refereed journal publications as a principal author in several fields of study. To balance his brain he runs, hikes, bikes, plays music and enjoys salsa dancing with his partner.
While corresponding with Dr. Antonia Orfield with respect to the brain adaptation in her research published in the Journal of Behavioral Optometry, Zach formed an understanding of biological adaptation in areas like vision and translated that knowledge to correct his running gait to avoid continued injuries. Having realized the faux paux in most modern running shoe designs/philosophies, he went cold turkey and started a brain reprogramming using proprioception gained from removing all artificial contrivances and let his brain evolve his perfect stride. He currently designs ultra-high resolution satellites for the betterment of humanity. He’s a space cowboy.
Listen to this episode of The MOVEMENT Movement with Zachary Bergen about what a physicist says about picking shoes.
Here are some of the beneficial topics covered on this week’s show:
– How supporting a system of the body tends to weaken it.
– Why you don’t get instant feedback when you wear shoes with support.
– How feeling good isn’t just a thought, it’s a physiological reaction.
– How shoes that provide a lot of support are a new phenomenon.
– How cushioning in shoes prevents the foot doing from what it does naturally.
Connect with Zachary:
Guest Contact Info
Email
zbergen@gmail.com
Connect with Steven:
Website
Xeroshoes.com
Twitter
@XeroShoes
Instagram
@xeroshoes
Facebook
facebook.com/xeroshoes
Episode Transcript
Steven Sashen:
When it comes to having comfortable footwear that can help with performance and health, I keep saying I wish more people knew physics because if they knew physics, they wouldn’t be susceptible to the marketing, I got to say, bullshit that keeps you from having the experience that you would like because of what big companies say and do. Now, people hear me say that and they go, “Hey, who are you to say that?” Well, why don’t we have that conversation with someone who’s an actual physicist? That’s what’s going to happen on today’s episode of The Movement the podcast for people who want to know the truth about what it takes to have a happy, strong, healthy, strong body. Feet first, because those things are your foundation, and we talk about the propaganda and the mythology. In this case, we’re going to be talking about some of the lies you’ve been told about what it takes to run or walk or hike or play or do yoga or CrossFitter dance revolution or whatever it is you like to do for fun starting with your feet.
And we’re going to, again, get rid of that mythology and propaganda, all the rest. We’re going to teach you what’s real starting feet first. Again, those things are your foundation, and we call this the Movement Movement because we’re creating a movement that involves you. I’ll tell you how it’s really easy about natural movement, letting your body do what it’s made to do. I’m Steven Sashen from xeroshoes.com. I host this thing and if you want to find out more and you do, go to www.jointhemovementmovement.com. Doesn’t cost you anything to do join. There’s no secret handshake or a song you need to learn.
That’s just the domain we got where you could find all the previous episodes, you could find all the ways to interact with us on social media, and if you want to be part of the tribe, it’s really easy. Just give us a thumbs up or a good review. I mean, if you want to be a part of the tribe, just subscribe. That’s the gist of it. Anyway, let us get started. I couldn’t be happier about this episode. And Zach, do me a favor. Tell people who you are and what you’re doing here.
Zachary Bergen:
Well, the high level, I’m a human on earth. There’s a lot of labels. I’m not really big on labels.
Steven Sashen:
You need to go down a little bit from human on earth. I’m okay with human on earth and I would argue that’s debatable for both of us. But regardless.
Zachary Bergen:
So I’m a physicist. I’m a practicing physicist actually with relevant experience, starting with NASA, doing shot mechanics, try to understand creating regimes. I had a paper called the Study the Collisional Fragmentation and Understanding Collisional Phenomena and Asteroid Evolution. But I’m here today-
Steven Sashen:
Well, wait, pause right there. I just need to say that you have just done something that is a first in the God knows how many, almost 200 of these podcasts that I’ve done. I think you just had more words that people would have to look up in a dictionary in a short time than ever before. So award for you, definitely a gold star and a trophy.
Zachary Bergen:
Right. And it’s my point here is to bring things down to earth. It’s meaningless. You don’t know anything if you can’t talk to people. And physics, it was one of my passions, optics, photography, running. I luckily was able to run high school before they had wedge-shaped shoes, and I had a Asic Tiger shoe that was a little more than a wafer that I ran cross country in the 19… we won’t say that. So yeah, I’ve got degrees, if you care about titles and stuff like that, to me, knowledge is knowledge. And I think a lot of knowledge is organically gained through experience. And to me, if it doesn’t work, forget about it. So I’ve got degrees in physics, graduate degrees, taught at the University of Colorado Boulder. Been a whitewater stunt kayaker, then performance, motorcycle riding, got smart, realized that people die doing that.
So I decided I wanted to have fun and stay above ground. And so running’s been a passion of mine for decades. And actually my history in terms of running, I reached a point where I did do all the wrong things because I didn’t think about these shoes that came out, went through all the orthotics, the best, everything like this, pronation, all these things. And then finally, I can talk about this later, but I made the connection between biological systems and healing and proper function versus these artificial contrivances that take you astray and never help your body. So there’s a lot more to my background. I’ve got a bunch of jobs on a long resume, but right now I’m designing a high resolution satellite to actually help humanity anywhere from agriculture to being a space cowboy, counting cows. So I’ll just stop with that.
Steven Sashen:
I got to tell you, you reminded me of a very funny thing, early on when Lena and I were running Xero Shoes out of the corner of a floor on the floor of a corner of a spare bedroom. And then actually by that time I think we had our first customer service manager living at our dining room table. We had living in our living room and the house and garage were filled with product. But we had some guys who were in town or passing through town to go to some sort of meeting at NORAD, and they came to get a pair of our sandals. And I said to them, “It amazes me when military technology makes it down to civilians and I always wonder what the military version looks like. So with GPS, what kind of resolution do you guys have?”
And they said, “No, we’re using the same satellites you are” this 13 years ago, “We’re using the same satellites you are. We get the same three-foot resolution.” And I said, “What can you take a picture of from space?” And they went, “Well, we can’t tell you that.” I said, “Well, from what I know, if you get three fuzzy pictures from different angles, you can use pixel level, near pixel level algorithms to clean those things up. And you put that together and you get a good 3D image of pretty much anything” and they just blanched.
Zachary Bergen:
Yeah, the big long word is called photogrammetry. And I’m an expert at that. And what’s interesting is the satellite feeds from the orbit, they call it SIS learner between the earth and the moon that are communicating the opposite direction from earth. So it actually is very interesting and a lot of the technology is 60 years out, so it’s actually very Star Trek and Star Wars and all this kind of stuff. So the problem for me is that bring it to the people instead of taking this game to space and polluting space. So anyway, that’s a whole nother conversation.
Steven Sashen:
Well, let me add this, because you and I have had some of these conversations. The part of me that likes to know how everything works is fascinated by many of the things that you know, and the part of me that wants to just have a simple happy life doesn’t want you to tell me any of that crap.
Zachary Bergen:
And you can be happy knowing both. Knowledge is power and I sleep well at night for many, many reasons because I have a way expanded view. Way outside of earth makes me kind of a space cadet. But-
Steven Sashen:
Well, let’s just say when I made that same comment to my brother-in-law who’s in the CIA, his response is, “Yeah, you don’t want to know what I know.”
Zachary Bergen:
CIA is spooky. Yeah, those guys, yeah, they’re spooky.
Steven Sashen:
So backing up to your running history, and I’m going to do the physics component of this in two phases. Phase one, I just want to hear what you were experiencing more specifically and then what was that kind of wake up call where you realized, I need to look at this with the actual understanding that I have about physics and reality. And then the next phase I want to talk about just what’s been happening in footwear and literally from a physics perspective, what your opinion is about some of these things. And it’s been interesting because there’s been a lot of stuff in the media lately. I was just on a panel discussion at the American College of Sports Medicine and brought up physics a couple of times and I’ll share that with you, but again, I’m kind of sick of it coming from me and it’d be much more fun to hear from you. So let’s start with your running history, the problems you were having and when you had that sort of like, holy crap wake up moment.
Zachary Bergen:
Sure. It happened by accident. So after I was competitive runner, I loved running and I ended up finding out that I was always trying to push myself too hard, but it crept up on me when I was just buying the next shoe and these wedge-shaped shoes came out and it’s fine, right? And then over time I experienced ITB and I’ve traced all these to pure physics. It is actually easy to understand. And then it was many, many years, but I started getting interested in longer runs and some of the overused things in repetitive motion injuries came in. So some of the supposedly small things started creeping up on me. So I’d go to the best Cairo and Boulder. I got my customer orthotics and went to the running stores and ran on a treadmill and had them analyze my gait, really bad idea.
The worst shoes I ever had were from that recommendation. So I experienced the typical problems that you would have in terms of people pronating, which completely goes away with zero drop and ITB, knee stuff, the patella not tracking correctly. So I mean the host of things that you all know about preaching to the choir. And the aha moment happened when I actually was doing vision therapy and I learned it was corresponding with this doctor, Dr. Antonia Orfield. And she had a paper in the Journal of Behavioral Optometry about a brain lung response in my opiate. So I read about that.
Steven Sashen:
Wait, hold on. Wait, slow that one down. So why were you doing vision therapy?
Zachary Bergen:
Well, I’m a physicist and I think in terms of optics, I’m an optic specialist. And what happened is I thought humans aren’t just doomed to failure. It’s just you don’t get to the point where, well, my knees are bad, I can’t run. And then my eyesight, why is that? And I found out that no, that doesn’t happen and that there’s a reason why people keep getting progressively stronger glasses. And so she actually cured her myopia, published the paper in the Journal of Behavioral Optometry, a referee journal publication. I corresponded with her, got in touch with a vision therapist, saw that vision therapist actually corrected my vision to where I was riding my motorcycle without glasses. And then having done that experiment, I realized biological systems, we have a genius design with our body. And so the point is, I took that knowledge, thought about running and said, you don’t just get to a point where you have to stop running.
Well, I can’t run anymore, my knees or something like that. And so I applied that same theory realizing that if you support a system of the body, you tend to weaken it. So what happens? And all you people wearing glasses keep this in mind. When you go to the doctor’s office, they want to look at the back of your retina. They dilate your pupils. What happens optically there is your focus gets worse, if they measure your prescription when you’re pupil’s dilated, they’re over-prescribed, get your glasses, you tell your friends, “Oh, I’m getting used to my new glasses.” They’re actually too strong. Your brain is adopting to that and your vision gets worse.
So I actually caught my brother before this happened to him and he didn’t have to wear glasses. So I reversed the procedure. And the point is that when you do that, then the lens gets confused and this are direct correlation between running and this because your onion skin lens needs to be able to accommodate and focus. So it needs to shift back and forth and find that perspective center. Same thing with your feet. If you have anything on your foot between your foot and the ground, it’s equivalent to walking around in a dark room looking for the light switch. You just don’t have that instant feedback.
Steven Sashen:
And I want to do a plug though for people seeing their ophthalmologist and having their pupils dilated and having someone look at your retina. Because yesterday I had the pleasure of having an appointment with my ophthalmologist and giving her a bottle of wine and thanking her for saving my life because during a routine eye exam, she found what was called a freckle on my retina. And she said, “I think we should monitor this,” which I didn’t know until recently. Let’s just monitor this as doctor speak for, oh, shit this could be cancer. And in fact, a year and a half later, it turned out that it was, and she was the one who kind of had a hunch, but she wasn’t allowed to diagnose that. So she sent me to the guy who diagnosed it and happily I went from diagnosis to being fine in eight weeks.
Zachary Bergen:
And I second that plug. So by no means does this mean that eye doctors are bad, there are just as many vision therapists who will take you the other way and they’ll put your accommodation just on the right side so you can actually improve your vision. So absolutely necessary eye health 100%. Of course.
Steven Sashen:
Okay. So you had this aha moment of going, huh? There’s a similar thing going on with my feet that I was doing with my eyes where supporting them was, and getting something in the way between you and the ground, was basically making you foot blind, if you will. And then what happened? What’d you do once you had that realization?
Zachary Bergen:
I went through a sequence of experiments. So there’s nothing like being a spokesperson for something, even though I’m not evangelical about this. If someone asks, I’ll help them, but I’m not out to change the world. What happens is I’m the Guinea pig, right? So Dr. Orfield was the Guinea pig and she proved by using her brain learn response to cure her myopia. So I started with the running shoe that tries to give you a midfoot strike and I ran a marathon with those. And of course, keep in mind the whole point was that I love to run and I was not going to be able to run because I’d run a half-marathon and beat the heck out of my body and wonder why is this? And fast-forward, by the way, today running a marathon and other distances, I just go about the rest of my day, it’s all gone.
I haven’t had so much as a tweak and I’m not kidding, in decades, a hundred percent. And it’s the big takeaway here is it’s not Zach, Zach’s not lucky. This is the nice thing about physics is we’re trying to approach truth and I can obliterate all these companies that they’re brilliant at marketing because they have the big shoe and the little shoe and the regular shoe and convince people that this year’s model’s going to help them. So what happened is I transitioned and I’m stubborn and it wasn’t quite enough for me. And I actually ran into some of the… became friends with Micah True, I guess they call it a movement. I don’t care about that. People who love to run, it’s not about being barefoot. If you are barefoot, you should be to get your stride a hundred percent about stride. It’s not to go into store barefoot and be radical about that stuff. It’s a hundred percent about your stride. So I-
Steven Sashen:
Let me pause right there. First of all, for people who don’t know, Micah True was featured in the book Born to Run and really introduced people to the Copper Canyon. Secondly, what you just said, I want to highlight it because this is something I say all the time, which is this conversation is not really about, I mean, any conversation that we have is not really about footwear, it is about form. It’s about using your body naturally. It’s about natural function. I was just at the American College of Sports Medicine, it was a panel discussion about how to select the proper footwear. And my opening slide was, you’ve been misled. This panel is not about footwear, it’s about optimal human function and how that can create comfort, performance and improved health. And then by the way, there’s some shoes involved, but that’s only about whether they get in the way of want or not.
Zachary Bergen:
Yeah. I’m dear friends with Maria Walton who was Micah True’s partner. And because of her death and she was distraught, I wrote her a song honoring Micah True called Caballo Blanco. And that ended up being in the movie, I think it’s called Born… I forget what the movie’s called, but I was at the premiere at the Dairy Center in Boulder and we had a bunch of Anton Krupicka and Scott Jurek and all the ultra runners there. So that was kind of a big night of just the coming together of what I would call a pure thread of what it really means to run and move across the earth and enjoy yourself and not get too worried and hung up about statistics, which was what Michael True was about. So I mentioned that because I ran to this crowd and synergistically of course you attract like to like, and people were running minimally and it’s really hard for people because there’s a metaphor here for fear.
So if you think about anything in life as you know if you tense up when you’re getting a shot, it hurts more. If you relax, it doesn’t. Same thing with walking the earth. You can, if you even just change your mind and think of your feet as just blending into the earth, which is inclusion and love, then the pain goes away. But if you’re like chicken hopping and thinking of the earth as a separate entity and that excluding versus inclusion, you’ll have with nothing else different except your mind, you’ll have a different experience of that walk. So I put two and two together. I went cold turkey in terms of realizing that you want to remove anything but feedback from the foot. So you want smooth, hard surface. So you want a perfect infinite half space and you just run and let your brain engage your muscles the way they were meant to.
And after three months, I felt like a kid again, and I had my sprint and I think you were there, there was a filming with a major network and a major anchor that was there. And we were run… I was actually, we were filming doing a spot on barefoot running and there was a sprinter from CU and I actually edged her out as the old guy because I had regained my sprint. And it’s just a joy that continues to this day. I sent the producer a picture of Natalie and I, my partner were doing our track work at 8,000 feet in Estes Park this morning in Xero Shoes, which I have some things to say about that. It’s not a promotion for Xero, but I’m very experienced because I was a science advisor on a barefoot running book. I think it was number one seller on fitness in Kindle. And I got to try a bunch of different shoes. And so I have experience, personal experience with this and then a physics background and mechanical engineering background to back it up.
Steven Sashen:
Okay, so I’m going to do a little paraphrasing. So when you went cold turkey, so I’m guessing what that meant is you went barefoot barefoot?
Zachary Bergen:
Yes.
Steven Sashen:
Got it. And I love that you mentioned smooth hard surface, which I always joke that if you want to make a barefoot runner, just misty eye, just mention a freshly painted white line on the side of a road. It’s like it’s nice and smooth, nice and hard, but it has just a little bit of something. It’s just totally delicious. And when did you do that?
Zachary Bergen:
Oh, good grief. Yeah, I’m supposed to remember dates, at least 20 years ago. And what’s interesting that is that as a physicist they have these things called rank of tensors and it’s like, okay, whatever. Bring it down to earth. How many dimensions are there? Okay, so we got three dimensions. And then time, you add a very real dimension when you’ve touched the earth in so many ways because you feel it, the temperature and the texture. And if you have a shoe on or you’re insulating yourself, you’re actually insulating yourself electronically. And so forget new age voodoo, you are electrical body, you can carry a charge. You literally ground your body that’s very real and you can build up charge. So people feel good when they walk barefoot because they’re bleeding off electrons, which of course are damaged to carry around. And if you’ve walked across a carpet with shoes on and shock someone, that’s literally proof that you build up charge. So there’s a lot of benefits.
Steven Sashen:
I got a different take on that one just for the fun of doing it with you. I don’t know if we’ve had this conversation. I don’t think we have. The thing I say is, yeah, you can build a charge. I mean your skin is really quite impervious to having electricity pass it, which is a good thing. I like to say 99.5% of people who are struck by lightning survive without a problem. 100% of trees that get struck by lightning explode because the current’s passing over you on your skin to the ground. In a tree it’s going through the tree, super heating the water, turning into the steam, things blow up. And I would argue, and I’m happy to be proven wrong on this one, that the thing that feels really good about having your feet on the ground is I like to give the analogy this way.
I say sugar doesn’t taste good. We evolve to like the taste of sugar and then manipulate sugar because it gives us something we need it, which is calories. And I suspect that that good feeling that we get is a similar thing where we learned that certain things tell us that what’s nearby is something beneficial, food, water, whatever it is. And of course feel, and it also just can feel good. And feeling good is not just a thought. It’s a neurological phenomenon that, and we also know that just being in nature has stress reducing benefits, which is also a neurochemical process, which is arguably physics as well. And so I go for this sort of simple biological evolutionary version of that story rather than electromagnetic version of that story.
Zachary Bergen:
And I don’t look at everything from a physics standpoint. I have my big organic spiel where it’s like, well, we call things organic because it’s the way things used to be. So it’s like the way things used to be, let’s mess it up. So you have food that’s just food, let’s mess it up and then call what it used to be organic. It’s like that’s odd. But I agree, I agree. There’s many dimensions to it.
Steven Sashen:
Look, we say the same thing. I say, we’re not the, when people ask me prove that what we’re doing is valuable, I go, “No, no, we’re not the intervention.” I mean human footwear for as long as we know about human footwear looked a lot like what we’re doing. In fact, even the first Nike shoe, the first Waffle trainer was flat, no heel lift, no toe spring. The toe box is a little narrow, but it was only about 10 millimeters of shitty foam. And so it was close to what we do than anything that’s happened once they added the wedge heel, which happened because some podiatrists who were in the same building as Bill Bowerman suggested that putting in a wedged heel would help people who were getting Achilles tendonitis. And 30 years later those same doctors said to a friend of mine that was recommending that wedge deal was the biggest mistake we ever made.
Zachary Bergen:
Yeah. That;’s like when Doc Holiday went to Glenwood Springs to help his health problems, it’s like exactly the opposite. Yeah.
Steven Sashen:
Oh, you know, it’s funny. Total tangent for the fun of it. We were just, my wife and I were just in the Czech Republic since we have our European office in Prague and we went to a town that is famous for its healing waters. And this town is over a thousand years old. And so I have a sneaking suspicion about what’s healing about these waters. Back then food was not great and digestion therefore was not great. And people would die from dysentery and other intestinal problems and there’s a lot of magnesium in this water. I think it just made them poop, that was really helpful.
Zachary Bergen:
It’s funny, a thousand years, my brother got his PhD in Germany. He gave me a thousandth year anniversary Stein. It’s funny, in the US it’s like, oh, this is historic building. It’s 40 years old. So yeah.
Steven Sashen:
Yeah. They like having when it was made and there’s a whole bunch of them that started with a one and a zero and it’s like holy moly, still in these buildings, they still work. So before we move on to footwear, I want to do one last little thing on the barefoot side. And because we’ve mentioned this is really about stride, is there anything that you can think of, and this could be a gotcha question because I don’t have an answer in my head. Anything you can think of from a physicist perspective about the phenomenon of changing, of how your gait changed and what’s happening when you are running barefoot biomechanically?
Zachary Bergen:
Oh, the problem with that transition speaking to a general audience is that depending on what you’ve done to your foot, if you’ve worn high heels and you have god-awful bunions, you’ve scrunched your toes up, whatever you’ve done to your shoe, you have your foot, you have to undo it to get your foot back to where it can function. And so for me, luckily I was walking around barefoot as a kid quite a bit, and you usually tried to wear as little shoes as I could and I hadn’t messed my feet up that much and I would at least take care of my feet and massage them and have foot rollers and do things all the time. So I was trying to get ahead of the problem of running the wrong way. And from a physics standpoint, it’s so obvious that I try to explain physics to people in ways you understand because it’s meaningless. If I said the Coriolis force is minus two omega across V, where omega is the rotational velocity and visa velocity vector, it’s meaningless.
Steven Sashen:
Well, except hold on. If when you’re running, you’re paying attention to Coriolis forces, you’re running really fast. That’s impressive.
Zachary Bergen:
Right. But you know, what I tell people is if you’ve ever been on a merry-go-round and you walked out to the edge or the center, that’s the Coriolis force.
Steven Sashen:
Yeah.
Zachary Bergen:
When you open a door, you open at the hinge or the handle, that’s torque.
Steven Sashen:
Okay. Yeah.
Zachary Bergen:
But people know this stuff. You can write an equation for it, but it doesn’t matter. It’s the physics that matters. And I always say math is the language of physics. Physics is not the symbology. The symbology is just represents, it’s a language. And people get caught up in that when they see that. Because if you see an all spot after it ranged in the grocery store parking lot, you’re looking at quantum interference, the oil actually has different thicknesses as it’s dissipating and light literally comes down and literally annihilates itself depending on the thickness of the oil. And you see a rainbow. So there’s so many physics things that you see that no one thinks about and they think, well, quantum physics, that’s some guy in the lab fermi or accelerating something, smashing atoms together. No, it’s every day. And if you have a glass of tea or your favorite sports beverage and you grab that glass and you see your fingerprints on the inside, that is an evanescent wave that you have literally brought into existence.
So this stuff is all around. And when you tell people that and common experience. So the problem with biomechanics, because you ask is that the difference is that instead of everything happening with the stack eyed of a shoe and then shockwave translating up through my leg to my knee, to my hip and beyond, I engaged the entire leg. And it’s so simple because, well, it’s the way we were meant to move. And it’s a brilliant design and it’s sad to see people try to correct something that’s not wrong with a shoe with support or an orthotic or the finding the light switch in the dark where you have more of a stack height. It’s the way that, these quick answers is the way the leg and the body was meant to move out of a brilliant design. And in physics be designed like springs and piston mechanisms, damped oscillators.
And so the calf is the shock absorber. And imagine if you had, I don’t know, if you took the shock absorber off of a car and drove it around, that’s what you do when you heel strike quite literally. And people would say, that’s crazy. I would never do that. What you’re doing it all the time. And so there’s so many problems with that because if we get into the physics of it, shock mechanics, there’s all kinds of stuff that would make people not want to run that way. So when you heel strike, you have a torsional instability and torsion just means rotation. And so you have this-
Steven Sashen:
In other-
Zachary Bergen:
… concentrated point.
Steven Sashen:
Your heels a ball and it won’t be stable.
Zachary Bergen:
And you’ll have a shockwave go up. And when it hits a refractive interface, believe it or not, there’s a lot of stuff that can happen. You can actually have at a change interface, you can have cavitation, which is rare faction. So I’m also a geophysical expert. I know about seismic waves, PNS waves, compressional waves and shear waves. It’s physics. This happens in your body. And so the more the transient shock is local shock wave, you can have shear stress, believe it or not, you can have cavitation, which can result in ultraviolet light, microplasma, free radicals over time like X-rays somatic. So if you have one big x-ray or a hundred small ones, it’s the same thing. So you’re running all the time and the more the shock wave at these microscopic levels, these things are happening and then all of a sudden you’ve oxidized and you’ve compromised your tissues and created all kinds of problems.
They just go on knees and ITB and this pronation thing, which vanishes when you don’t heal strike. So it’s so obvious because if you hit your heel, you have a double impact. So I’ve done this at CU on pressure plates. I’ve run with the traditional shoe run barefoot, as you know, you have a shockwave that’s two peaks if you heel strike. But the problem there is that you have unstable landing, you overload the arch and you stop for an instant and then you push off again. So it is like stop, start, stop, start, stop like a jalopy. And my analogy is, if you look at legs across the spectrum in terms of dogs and rabbits and deer and humans, where’s the heel on a dog? Where’s the heel on a deer? What if they ran around hitting their heel? It’s not any different. It’s the same.
And the reason gazelles can run so fast and so gracefully is the same reason we can, they would never heal strike. It’d be laughable to see that. And so we have a little bit different ratios, the Fibonacci and golden mean and all that kind of thing, the brilliant design of the body. But that’s the basic idea is if you make the analogy between these animals that run, they would never land on what is the equivalent analogy of the heel in terms of the skeletal structure. And it’s just obvious to me. So it’s hard to even describe because your leg was designed for your heel to be kind of like a cantilever thing. And the brilliance of your forefoot is that it can splay and absorb shock and then also return that. So it’s a little bit lost. This is an inelastic collision, but you’re actually dissipating and morphing to the varied terrain and loading up the calf and the thighs and using from at least the hip down.
And so you have that distance involved versus this really teensy distance that you’re trying to accomplish with the shoe. And it’s crazy speak. It’s just crazy. And it’s truth, it’s not Zach’s opinion. I’m not trying to… We’ve done shock tests. I’ve literally done shock tests loading like rods at NASA and seeing what happens with the shockwaves. So I know my shock mechanics and I’ve tested materials to failure and I know that especially with repeated injections of frequencies into systems, you can actually have a catastrophic resonance and catastrophic decline and failure, which is famous in certain bridge things. So here you are heel striking, causing these shockwaves to go up your leg, hit a refractive interface of the hip or the knee or something like that and you have these cavitations, and you have these little free radicals, and all of a sudden your tissue decomposes and you go to the doctor and it’s like, “Well, we’re going to have to replace your knees because, and you can’t run anymore.”
Steven Sashen:
Hold on, this is a really interesting thing. People think that if they end up with, let’s say, patellar tendonitis, tendonitis around your knee, the way it’s talked about now is that this is a quote, overuse injury. You’ve just been using those muscle ligaments and tendon around your knee too much and that’s why they’ve degraded. What you’re suggesting is something much more interesting, which is that it’s not an overuse injury, it’s in this case a shock based injury that’s just affecting the tissues. So you can use them all day long if you weren’t creating those shocks and cavitation. The easiest way for people to think of cavitation in my mind, tell me if you have a better one, is something like a carbonated beverage where you can basically create these bubbles out of the water by changing pressure or something.
Zachary Bergen:
Yeah, bubbles coming out of suspension. It’s like the bands for nitrogen, the bands came from people building the Brooklyn Bridge and those caissons and they had to pressurize it to keep the water out. And that’s workers would come up into, the nitrogen would come out of there when they came up top side out of the pressurized air, the nitrogen would come out of solution to their blood and fall over and die or have some maladies. Exactly same thing. There’s a really good analogy. So I use physics terms and I try to translate things because when I use things like shockwaves, people know that when you hit something, it goes through a material, but you don’t know that the amplitude can double and do weird things at the interface. So it really matters.
And the other really, really big takeaway is that your body, the bones weren’t meant to be loaded like that, your fascia and your muscles and your ligaments and tendons are really supposed to do most of the work. And you need some kind of structure, I guess to have form and my job, self-appointed job is when people ask is to try to bring this down to earth. And it’s so simple though. You can take your shoes off and go for a run. Tell me if you’re going to heal strike.
Steven Sashen:
Right.
Zachary Bergen:
And then people have that thing though, it’s like, “Well the earth is scary and I can’t touch it because what if I step on something?” And I said, “Well then don’t step on something.”
Steven Sashen:
Oh my God. The number of times where someone says, and look, we’re not recommending going barefoot per se, but the number of times… But what people do when you do suggest that idea is exactly that. Not only do they say, “What if I step on something?” They imagine stepping on things that don’t exist in their world. My favorite is actually, “What if I step in dog shit?” I go, “When was the last time you stepped in dog shit?” They go, “I don’t know, 20 years ago.” I said, “Well why are you going to start now then?”
Zachary Bergen:
Right. That’s a good answer. But the thing is about the shoe is I agree, it’s that in fact, going way back to when I said stride, it’s not bare barefoot, cold turkey, organic, I got to be barefoot, touch the earth. It’s stride. And when you have your stride back then if you do this mental gymnastics, this mental math, it’s like, okay, well then I don’t need the padding anymore. Right? You’re right, you don’t. And then what happens though, if you run a trail or you run on these artificial surfaces, so even these open space trails, they grind these rocks up and they’re pyramidal shaped and they will just bug the crap out of you when you’re running. So what happens then? If stride rules, then you start doing that, you start chicken hopping, you change your stride.
So absolutely appropriate to have the most minimal shoe you need. And you know me, I’ve been running, well, I met you when I took a blank of Vibrament and some shoelaces and built a sandal when you were just starting this whole thing. I went over to your house and looking for the most minimal thing. I’ve run everything you can imagine in the, I guess Xero sandals, different incarnations over the years. And I don’t know, I’ve never actually worn any of mine out, which is odd. I see people wear them out, but I think it’s because I had a stride.
Steven Sashen:
It is.
Zachary Bergen:
I took my stride.
Steven Sashen:
The thing that I say, I mean, we build these things to be durable. And I say, but the difference is this, if you were just standing up and just lifting your foot off the ground and putting it down, lifting up, putting it down, just all vertical force, no horizontal impact at all, then it’ll never wear out. And so if you’re starting to see wear patterns, it’s because you’re creating horizontal force. Friction is friction. And that doesn’t mean you never create horizontal force. I mean as a sprinter, my first 20 steps are as horizontal as you can get away with. That’s how you’re building up speed and slowing down does the same thing in reverse. And even if you’ve got a really good stride, there’s a little bit in there, but that’s a whole other story. I want to jump into this a little bit from what you just said. So considering that the entirety of footwear evolution in the last 40 years in particular has been adding various forms of cushioning, can you say again, from a physicist perspective, what cushioning does and/or doesn’t do?
Zachary Bergen:
It removes your foot’s ability to do what it was intended to do. First of all, no matter what, no matter what, in fact, the way I think of the perfect shoe is that it’s just a magic carpet that follows your foot around. It removes the whole idea of having a last that you have to cinch down. And people are so used to cinching down the last because they’re trying to spring off of their foot and have this thing really tight on their foot. So the cushioning thing insulates your proprioception. So from a physics standpoint, it confuses your brain. So there’s called a brain limb response and as you know, proprioception, and what it does is it confuses the triggering of the muscles. So the short answer is it confuses the triggering of the muscles. It’s always, always suboptimal no matter what. And a lot of people get away with it and say, “I run just fine. I run just fine.”
You might not have major injuries, but you absolutely could always run better. No question, always could run better. So when you put a, even if it’s a zero drop a bunch of padding on your shoe, it takes, the stress has to go somewhere. And so anything that’s happening between your foot and the ground isn’t happening with your natural accommodation, with your muscles and the hinge motion and the pistons in your calf and the way they were tended to work. And so it’s less efficient and it confuses your brain. Like I said, it’s like walking around in the dark, your foot needs to be able to splay. And then also if it’s not perfectly planar, which trails and roads aren’t, it needs to be able to accommodate that. And what you’re doing is you’re removing a complete dimension when you do that. So now you’re saying everywhere you step is flat. And not only that, if you have a slight rocker in the road, now you’ve introduced an unnatural, let’s say, torque or torsion, which is a twisting to your ankle. And why? Because all that goes away. Like I’ve been running-
Steven Sashen:
No, no, the why is really simple because shoe companies have been misusing physics to convince you that you need this stuff. And every few years they come up with some new version of cushioning and they never say, here’s our new stuff, sorry about the crap we’ve been selling for the last five years.
Zachary Bergen:
Well, I don’t think they’re even using physics. I think that they’re brilliant marketers. Some people can sell you water that has caramel color brilliantly and it’s a travesty. But no, it’s marketing because well this-
Steven Sashen:
No, I said misuse physics.
Zachary Bergen:
Oh, misuse. Well, yeah, I mean that would assume they’re even using physics because you can’t-
Steven Sashen:
No, no. Here, let me give you my favorite example. So Adidas and I say that to be pretentious because that’s how you say it in Europe. Because that’s what it is. They invented their boost foam and the way they showed how great it was was they took a two pound steel ball and they bounced it off of cement and it barely bounced. Then they bounced it off the other company’s foam and it bounced a few times, then they bounced it off the boost foam and the first bounce came up about 30% of the height that they dropped it from. And then it bounced like 10 more times. And so the misuse of physics, of course, is I immediately knew that if you want to get a steel ball to bounce really high, you have to bounce off a steel plate with a bunch of concrete underneath it and the first bounce will be 99.5% of where you dropped it from and it’ll bounce about 200 more times. So that’s a misuse of physics.
Zachary Bergen:
You’re losing energy. It’s like why would you want to do that? That’s the funniest thing. I see some of these stores have this, they sell people this shoe because it’s got memory foam in it and it’s like, “Look how comfortable that is,” it’s, oh boy, instant gratification society, but it’s really worth it because I succeeded in getting my partner to run minimally and we went sprinting today and she was hitting four thirties, short distances when it wasn’t doing that before. And I said, well, it’s because of your stride. And I’m sitting here, what, 62 going on something, I go out and I run pain free and I can sprint like mad and I do it because it’s fun. It’s not like, well I got to hit a PR, hit some master’s record. Which is nothing wrong with that, but I’ve always loved that. And to have that, you lose that if and you take someone who is got “the wrong shoe,” this gigantic stack height heel protector thing, have them go to the track and watch them sprint and they’re not going to heel strike. And-
Steven Sashen:
Well I’ve seen people who do because-
Zachary Bergen:
Oh my gosh, I hope not.
Steven Sashen:
No, no, absolutely. Because for them they just think sprinting is just moving their legs faster in the same pattern. So that’s what I’ve seen more times than I would care to admit or more times than I would like to admit.
Zachary Bergen:
My dilemma is that I understand this solidly, there’s no doubt about it. Like stride rules and these running shoe companies are brilliant marketers and they’ve come up with capturing three markets now instead of the one, and I don’t understand people, it’s a whole other psychological phenomenon is that sociologist friend of mine wrote a book, he did some research, found out that on average people make decisions based upon what they think other people think. So that’s twice a removed from reality. So if I fantasize what I thought you believed, which is not true, and then I adopted that, that is why drug commercials work because you have a cartoon of these red dots that turn green. Well it worked, and then you go take your problem you don’t have and you create more problems. So it’s an interesting philosophical question because if you love people and you love humanity and you want them to have a better experience, you know they could be moving better and pain free.
But there’s so many competing things out there, they’ll say, oh my god, no, they’ll try to find something wrong with a micro statement you said and try to prove you wrong and discredit you. But that robs everybody the experience. And I’m living proof and I’m not special. I’m not a natural-born runner. I’m a natural-born loving to run person, but my biomechanics in my body isn’t ideal for any particular type of running. So for me it’s even more important they call them the middle packers, people who just want to get out and run. They could always have a better experience. And it’s very hard even to take a highly intelligent person and help them make the switch even if they want to.
So I had a friend who was sold and I was running in the Northeast when I worked up there, running barefoot everywhere, on trails, roads, everything. And he said, “I want to try it.” So he shows up with a pair of this wrong brand of barefoot shoe and I just, my heart sank because he was convinced he tried it and he said it didn’t work for me. So he just completely lost it. He lost the opportunity and he was an intelligent person that was signed up to try. And so given that these other people look at the latest shoe and it’s the next shiny thing, which is rampant in our culture in many ways.
Steven Sashen:
Yeah. Well there’s another piece to this I’ll throw in, actually I got to tell you this at the ACSM event last week, I was one of the people on my panel was from Brooks, and at one point he said, we’re trying to put more spring in your step and propel you forward. And I grabbed the mic and I said, I asked him, I said, “Would it be okay if I’m a little obnoxious for the next 30 seconds?” He said, “Yeah, sure, go for it.” I said, “There’s nothing that can put spring in your step or propel you forward. This is called physics. All foam sucks energy out of your system, nothing moves you forward. If anything did, we’d be able to see it in force plate data, which would be really compelling. And none of you have shown force plate data because it doesn’t work.” And he conceded the point, he said, “Yeah, we’re not trying to violate the laws of physics, we’re just trying to give you something that works for you.”
Zachary Bergen:
Well, yeah, if you want to convince someone with the big stack height shoe not to wear that shoe is like realize that every time you land, all that energy is getting dissipated. It’s not storing kinetic potential energy, right? He rolled the boulder up a hill creating a huge amount of potential energy and then you let it roll back down. That’s kinetic energy. So you give all your energy away and then have to start all over again. And it’s really appropriate what you said about accelerating, maybe not having too much friction during a stride, but when you’re accelerating, decelerating of course you have a large torque to get to maintaining speed. And then if you’ve got your really nice turnover, which I work on with my track workout, then it’s just a joy. And it gets down to though, why are people doing things too?
And I was a fitness captain at a company, a major aerospace company, physicist by day doing exotic stuff and it’s really, it is exotic, really cool stuff that blow your mind. You can see underwater and in space. But let’s see, fitness captain and I really wanted to help people and I said, pick a realistic goal, like a life goal or at least a 10-year goal and don’t impose some type of idea of what you should be able to do. And I was trying to help find ways to help people make that leap. And there’s so many body identification problems in this world and idea of what you should be like. You’re a natural sprinter. And I’ve found that I’m not really necessarily great at long distance and I actually feel better when I sprint. If I go I’ll do a warmup, hit the track, and I love running as fast as I can today. It was like four 30s I’ve done three 20s and for short distances, not my Steven Sashen level stuff, but I’m an older guy and I’m hitting it, man, I’m burning it.
Steven Sashen:
First of all, I dropped the older guy crap. I’m a year younger than you. I’m turning-
Zachary Bergen:
Well yeah, I know, I mean-
Steven Sashen:
… I’m turning 61 in a couple days.
Zachary Bergen:
But it’s cool because who wouldn’t want that? Let’s be free.
Steven Sashen:
I agree.
Zachary Bergen:
I don’t take ibuprofen, I don’t have all these little secret things I do.
Steven Sashen:
No.
Zachary Bergen:
And it’s a hundred percent because I changed my stride though 100% because I was everybody else. And when you don’t use your body correctly, you break it down.
Steven Sashen:
Well, here’s something that you’ll find entertaining. When we were in Czech Republic, there’s a half-marathon in the town we were in, and I watched everyone run by me as I was enjoying a pleasant dark beer locally made. And the first 70% of the runners, every one of them, midfoot strike four foot strike. And you would think that that would make me happy, except that they were still wearing shoes with a whole bunch of cushioning. So they’re losing all that energy. Now granted, many of them were running at a speed and they had a body weight, a mask that was appropriate for that cushioning. In other words, it was sucking the least amount of energy out of them possible because foam is basically tuned to a weight and speed.
But you would think that I’d be happy they were midfoot strike landers except that their heels never touched the ground because of the thickness of the sole and the heel. And so they were losing all that last bit of their Achilles stretching in energy and then coming back. So they were less energy efficient than they could have been. But because the higher heel has trained them to not let them use their Achilles, their brain basically goes, “Oh, my Achilles can only stretch this far” instead of that extra few inches that they were losing.
Zachary Bergen:
And as you know a formula for disaster and sprinting is if you don’t use the full range of motion, if you think you just, like you said before, if you just think do what you’re doing, but do it faster… you’ll pull a muscle, you’ll rip an Achilles apart. That’s a really good point because the loading and unloading, what I found is the body is such a brilliant design and it seems so weird if you look at an x-ray of a foot, I wouldn’t have come up with that. But it’s just brilliant because people, like when you doing yoga or something, unless you’re a martial artist and you’re doing knuckle pushups, you understand about using your hands to distribute stress.
And people can do that, but your foot does the same thing and you just throw all that away. And it’s arrogant actually to think that a shoe company can better the foot. And it’s arrogant to think that a scientist can do nanotechnology to better the hummingbird that I was standing there that was going to refill my feeder and I’m holding it and it’s right here looking at that design right in front of my face and the sheer arrogance of thinking that we’re an advanced society and we have ChatGPT, and we can offload any accountability or creativity to AI. Not going to happen. That’s a whole other threat.
Steven Sashen:
Well first of all, we have to wrap this up, but secondly, I want to appreciate that you have been willing to jump into the world of Newtonian physics rather than the more esoteric versions of physics that you spend your days in. So I appreciate that. And it does amaze me watching what footwear has turned into and what people believe of course as a result, and I mean, again, when I say people should know, understand more physics, it’s because if you do, you aren’t susceptible to these things that people say that are so clearly not true. When you understand things about force production, for example, and what you brought up about stress and about wave activity, I’ve lost the ability to think in English, is so, so interesting for people to think about.
Just you know, if you’re landing on your heel, if you are just sending a shockwave up your calf basically into your bones, that energy’s got to go somewhere and do something. And what we’re wired for is to have our muscles ligament tendons get in the way of that to get there first and accommodate that. And if you bypass them, that’s going to be a problem. Look, when the first big thick shoe came out, I won’t mention it by name, let’s call it, Smoker, they-
Zachary Bergen:
I can imagine what that is.
Steven Sashen:
I’m just saying. I mean I just made that up. I don’t know where it came from.
Zachary Bergen:
No, I don’t know.
Steven Sashen:
There were some professional runners that were on the track with me and I said to them, they love these shoes, they’re getting in more miles. I said, it’s going to mess up your knees in a couple years, you want people to run and you’re out of your mind. And partly they didn’t believe me because look at me, but two years later, none of them could run because all that shock was going into their knees. They weren’t feeling it and it was causing those problems. But I’m still loving this idea that of the idea of the cavitation of the fluids with it around those joints causing problems to the tissues instead of it being overusing. That is blowing my mind.
Zachary Bergen:
That is something that happens. So it’s called somatic and x-rays. If you get a bunch of small ones, it’s the same as getting one big one. And so when you’re doing this to your body, you can break it down. And these microscopic level, like I said, you’ve got free radicals and UV light, and we all know about UV light. We buy plastics that are not as susceptible to UV light. We all know about that. And microplasmas and it just seems like, no, that can’t happen. It’s like, no, it’s physics. It’s a shock. It’s a refractive interface and there’s a PNS wave that gets transmitted and reflected. And then to get really technical standing wave ratio is how efficient that energy is, so if you have a rope and you shake it, you send a wave through it. If you tie a piece of dental floss to the end of it, the dental floss is going to go crazy.
If you take the dental floss and shake it and tie, shake the dental floss, the big rope’s not going to budge. And so that’s really the physics and it’s so easy. But my dilemma is I have to, like I said, with opening doors and the merry-go-round and all spots and glasses of tea with your fingerprints, I have to bring it home. And I can’t say torsional instability. I have to show people, well just try run around your heels and tell me how that works for you. And then stop thinking and just take this smooth hard surface and go from here to there at a jogging pace and now watch them. And it’s like, yeah, they’re stride immediately improve, their head’s not bobbing up and down all over the place. And I’ll tell you one thing, those shoes that I can’t remember the name of that, you can’t either. Those big clown shoes try, it’s like running in a jumping castle.
Steven Sashen:
No, I mean, someone gave me one of the new Nike Vaporflys, and I put it on and I took two steps trying to sprint. And I felt like I was in quicksand because, again, I was moving at a speed much faster than that material could handle it.
Zachary Bergen:
Right, right. Right. But there’s more and more and more and more and more technical stuff. And I guess the takeaway is, my rule in life is theories are great, but it has to work. It has to work. And I was literally looking at not running, and I changed my stride and people would have to run with me and see I sleep pain free. I run like a demon pain free because it was using my body the way it was meant to be used. And I did that hopefully to save other people the time because I did do the work and I discovered it for myself. So I grew it organically. I didn’t find a book. I can’t recommend a book. It’s coming from me.
So I’m sole sourcing this information. And I was able to take my hard grounding in mechanical engineering and shock mechanics and Double E and fiber technology and physics and optics, take all of that and some correspondence with some real doctors who are published that do real research and today benefit myself and then want other people to be able to experience that because their experience can always be better. And I guess it’s kind of tough because the shoe industry would radically change.
Steven Sashen:
That’s a whole… Yeah. We don’t have time to go down that road. In fact, we got to get out of here. Zach, it has been an absolute pleasure. By the way, if people do want to just ping you and say thanks for asking a question or whatever, how can they do that?
Zach:
I guess, I don’t brand myself. Like I said, I’m a full-time physicist and I actually have a physics job. I’m a practicing physicist, but I have email, just first initial last name @gmail. I don’t do anything fancy. I have a website, but my website only allows for virtual reality and it’s toe wacky. It’s crazy.
Steven Sashen:
That’s okay. So Z-B-E–R-G-E-N @-
Zach:
Yeah. If I get put my hand radio hat on, it’s Zulu Bravo Echo Romeo Golf Echo November @gmail.com. So Zach Bergen, Z-B-E-R
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