Isabel C. N. Sacco is an Associate Professor at the School of Medicine of the University of Sao Paulo (since 1999); 1B Research fellow of CNPq-Brazil (National Council for Scientific and Technological Development); and the head of the Laboratory of Biomechanics of Movement and Human Posture (LaBiMPH), whose main areas of research today include intelligent systems for decision making in health, biomechanics and rehabilitation of diabetic patients.
Within this decade of professional experience, Prof. Sacco has an extensive academic production, including over 100 papers published in journals with IF (H index=16), more than 300 complete or extended abstracts in international and national conferences, a book, 5 books chapters. Her teaching throughout her career includes the guidance of 9 doctoral theses, 17 master dissertations and 5 post-doctoral supervision.
Currently is acting as Director of the Graduation Program in Rehabilitation Sciences at School of Medicine at the University of São Paulo. She has recently been honored by the Brazilian Government as one of the only 22 young (under forty years old) female Brazilian scientists in the national territory with a recognized merit, building up an academic carrier of national and international recognition with extensive scientific production and important role in the formation of human resources.
Listen to this episode of The MOVEMENT Movement with Dr.Isabel Sacco about how to reverse knee arthritis.
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Episode Transcript
Steven Sashen:
Everybody knows that when you get older, your joints wear out, you get arthritis. It’s just part of getting older, right, maybe not. Maybe something like knee osteoarthritis is just caused by something else and cured by something else. We’re going to find out more about that on today’s episode of THE MOVMEMENT Movement, the podcast for people who want to know the truth about what it takes to have a happy, healthy, strong body, starting feet first because those things are your foundation. We break down the propaganda, the mythology, sometimes the outright lies that you’ve been told about what it takes to run or walk or play or hike or do yoga or CrossFit, whatever it is you like to do and to do that enjoyably effectively, efficiently. And did I mention enjoyably? It’s a trick question. I know that I did because look, if you’re not having fun, do something different till you are. Because if it’s not enjoyable, you’re not going to keep it up anyway.
I’m Steven Sashen, your host of THE MOVEMENT Movement podcast and the co-founder and CEO of Xero Shoes and XeroShoes.com. And we call it THE MOVEMENT Movement movement because we are creating a movement that involves you. Doesn’t cost anything, really easy. More about that in a second. About natural movement, we’re helping people rediscover that letting your body do what it’s made to do is the better obvious, healthy choice. The same way we think about natural food and the movement part that involves you, easy. Go to www.jointhemovementmovement.com. You don’t need to do anything to join, just the URL. But that’s where you’ll find all the previous episodes of the podcast, the different ways you can interact with us. You can find us wherever you find podcasts, but also on YouTube and Facebook and Instagram, et cetera, et cetera. And then subscribe and like, and share and all those things you know how to do. In short, if you want to be part of the tribe, please subscribe.
All right, let us jump in. Dr. Isabel Sacco. It is a pleasure to see you. We’ve had some email volley since we met a couple of … Man, it seemed like simultaneously very short time ago because of COVID, but also it’s been a number of years since we met at the International Foot ad Ankle Biomechanics Conference. So pleasure, happy to have you here. Tell people who you are and where you are and what you normally do.
Dr. Isabel Sacco:
Yeah, it’s very nice to be here. Thank you for the invitation. Well, I work at University of Sao Paulo at the school of medicine, particularly to the department of physical therapy. I run a biomechanics lab. It’s here in Brazil, and my research main focus are people that has some dysfunctions, mostly skeletal and neurological dysfunctions, such as diabetes, neuropathy and knee OA. So we’ve been studying this for like 20, 25 years. And we jump into the foot and the importance of the foot. So this is what we’ve been doing for the past few decades.
Steven Sashen:
So what was it especially about? So knee osteoarthritis, knee OA, is something or, and KOA, depending on who you’re talking to and how clever they want to be, this is something that obviously plagues many, many people. What was it that got you interested in studying that to begin with? And by the way, a little teaser, we’re going to be talking about your research and the thing that you presented at IFAB that was, I think, for many people shocking and a lot of people didn’t even want to believe it and still don’t, but we’ll get to that in a sec. But why, what got you interested in this aspect of biomechanical research?
Dr. Isabel Sacco:
Yeah. We’ve come across to a paper in 2006 from a group of Rush University in Chicago. And they found out that walking barefoot people that has knee OA, elderly people walking barefoot produced less impacts or less joint moments at the knee comparing to walking with a more structured and more cushioned shoes. We were shocked about that in the beginning. And then this same group, this group from Chicago, they studied and adopted a shoe that they did cuts in the sole of the shoe to make the shoe more flexible. And their results were also very interesting.
The loads were too higher compared to the barefoot walking using this different shoe, but it reduced compared to more structured sportive shoe. So then we were wondering if we could reduce loads in those knees, in those damaged knees using a very popular shoes that we have in Brazil. It’s very inexpensive. It’s very cheap and very common and it’s a minimalist shoe. So we wanted to give the opportunity for this population to have a more conservative solution for the loads, considering that the loads in the OA is the main cause of the progression and the pain and the reduced function. So we wanted to reduce loads in order to reduce the progression of the disease. Yeah, go ahead.
Steven Sashen:
I want to pause there for a second, because you said something that I think is critical and often misunderstood, and what I teased at the beginning, is that the arthritis is often caused by loading forces, just progressive loading forces into the knee joint. And I know there’s animal studies that show this. You basically take an animal’s leg, make it relatively straight and just percuss the heel just continually I’m trying to think of another word for percuss for people who don’t know percuss, a bang on the heel. And that creates loading forces in the knee, which leads to arthritis. Most people think of arthritis as just a natural degenerative process, but you’re suggesting that’s not the case.
Dr. Isabel Sacco:
The main villain of the OA is loads and it came from body weight, increased body weight or activities that you accelerate the body, accelerate the mass, like running or jumping or do gymnastics or if you use your body in way that your musculoskeletal structures could not absorb the impact properly. So if your body is not adequate or trained or strong enough or functional enough, you may experience more impact in your joints. So you could train your body or you can use tools or shoes or whatever to help your body to respond to that impact and absorb them in order to avoid loads and avoid the progression of degenerative diseases such as osteoarthritis.
Steven Sashen:
This is the thing that we obviously talk about all the time and people ask us why is there no cushioning in your Xero shoes? And I say because there’s no manmade cushioning that performs better than your muscles, ligaments and tendons. And of course the cushioning wears out the moment you start to use it. Your muscles the more you use it, the stronger they can get, or the stronger they can stay as you experience sarcopenia when you get older. It’s amazing that people somehow think that cushioning is better than your body and more cushioning is better. And of course the research from people you’ve already mentioned, Christine [Paulard 00:07:59] and others show is that the cushioning just doesn’t work.
And yet I say it’s like the story of the boy who cried wolf with the shoe industry is every couple years, they’re the shoe industry that cried cushioning, is they have some new form of cushioning and people just run to find out what it is. And the difference is in the boy who cried wolf, the villagers eventually got smart and don’t show up, but shoe company that tried cushioning, for whatever reason for the last 50 years, people keep showing up over and over despite the lack of evidence for the efficacy of cushioning. It just blows my mind. Anyway. So to then backing up to your study, who was the population, what was the population that you decided to research?
Dr. Isabel Sacco:
Yeah, it was elderly or older adults, female older adults. Because the shoes we wanted to test is a for women, so the only population, the only … Yeah, we had to test only in women. But I’ve heard that there is some of course Xero shoes and I could test also the Kung Fu shoe, which is also very flexible, people that do Kung Fu. Well, we tested women. They were over 65 years old till 80s. They had knee OA for quite some time. And the degree, the severity degree were from two to three. We have 1, 2, 3, 4 levels of a severity of OA. The fourth level, you have to go to the protheses. So you have to go to surgery. So we wanted to have people that is not at that severity level. So two and three. Why not one? Because one is not conclusive, so people don’t know if they have OA or not. And those grades are diagnosed by x-rays, simple x-rays.
Steven Sashen:
I’m glad that you said that because there are a number of, let’s call them studies for lack of a better term, where it’s just based on perceived pain or perceived problem that you actually have real data. There’s x-ray data, there’s radiological data showing, no, no, this is a real condition regardless of what their experience of it is. Because some people will have feel more or less pain, but the oestoarthritis is undeniable. Here it is on the x-ray film. Well, it used to be film. I don’t know if you had film or if it was digital at that point.
Dr. Isabel Sacco:
Yeah. It’s digital.
Steven Sashen:
Then what was the intervention and what was the design of the study then?
Dr. Isabel Sacco:
Yeah. Before we planned, this randomized clinical trial, we did some cross sectional studies to test if this flexible, minimal shoe like the ones you have behind you, but a Brazilian kind, if these shoes really work, reducing the knee loads, the knee adduction moment. The knee adduction moment is one biomechanical variable that we measured and has been described in the literature that has a very intimate link to the progression of OA. So if we measure using kinetics and do an inverse dynamics calculation, we came to this joint moment that at the end mean loads in the knee. So we measured this knee moment.
Steven Sashen:
I was going to say for people who are not as proficient or familiar with some of the terminology that we’re using, can you describe, can you say more about for people who are trying to visualize this, what does that knee adduction moment look like, how would they experience it themselves?
Dr. Isabel Sacco:
Yeah. When you walk, the loads of your body go in the medial part of your knee usually. And this load when it goes to this medial part of your knee, it creates a bending movement. So this bending movement in the medial lateral bending causes a torque, a rotational torque … Rotational effect in the force. And this rotational effect of this body mass going into your medial part of the knee causes loads. And these loads, depending on the magnitude, it could degenerate the cartilage over and over the years. That’s why everyone will get at some point in your life, a degenerative condition in your cartilages, if you don’t prevent this increase of loads. So these measures, what we did in our lab was testing, doing some locomotive tests like walking, going up and down stairs. Is that everything okay, are you hearing me?
Steven Sashen:
No, no, that’s good. No, no, you’re on it. And again, I’m going to try and hyper simplify it as well. If you think about your thigh and then your lower leg and then the knees in the middle, and when you’re basically just applying force from doing almost anything, the actual force is getting into the middle of that knee joint with some … There’s some torque. It’s not just straight up and down, especially because you’re not actually landing that way. And just the angles of that, the different angles that that force is applied is just creating some wear and tear. And if is the important part there, if you don’t have musculoskeletal, muscle ligaments tendons, if the soft tissue isn’t really strong enough to support that or reduce that.
And you made me think of something that I hadn’t thought of for a long time. When I was 32, so 17, 18 years ago, I was a gymnast. I landed while twisting and heard this sound coming out of my knee. And I fell to the ground thinking, “Well, that was the end of my gymnastics career.” And it was, and what was interesting to me was that I ended up having about 30% of the cartilage removed from my knee, my meniscus, which was also really fun because I had them do the surgery by giving me an epidural. So I got to watch the surgery, which was very entertaining. I’m a geek that way.
At one point I’m watching it on this giant television. I said, “Can you take the instruments out so I can see how big they are?” Because on TV, they’re huge, but they’re tiny, tiny little arthroscopic instruments. Anyway, point being, for years afterwards, for many years afterwards, I had trouble walking, running. I had been doing Tai Chi before that. I couldn’t do it because it was so painful. And then to make a long story, very short, did some rather intensive knee strengthening work and have been fine ever since. So what happened apparently was just that my soft tissue just wasn’t strong enough to handle that change and the structure of my knee. And no one diagnosed that properly for years. Then I have this crazy MD friend. That was what helped.
So, even having significantly less cartilage in my knee to protect it, I’ve been fine for the last, whatever I said, two years minus however long ago that happened. And have been obviously running, et cetera, et cetera. So, it just highlights how much protection one can get from … Stronger is better. The weaker is the simplest thing we can say.
Dr. Isabel Sacco:
Yes. Yes. I always like to give examples to my students and people that I talk about that. There are some studies that compare, for example, the amount of mechanical energy that some of the musculoskeletal structures of our body absorb during walking and running. For example, just for a matter of comparison, when you take your thigh muscles, the quadriceps, it absorbs 66 Joules of mechanical energy each step of during running. If you go to the triceps surae or the gastrocnemius muscle … I don’t know the-
Steven Sashen:
Calf, your calf muscle.
Dr. Isabel Sacco:
Yeah. Calf muscles. We say belly of our leg in Portuguese. I don’t know in English. It’s belly.
Steven Sashen:
No. That’s not an English phrase, but I like it.
Dr. Isabel Sacco:
Yeah. So this muscle absorbs like 26 Joules. If we’ll go to the plantar fascia or the arch of the foot, only one structure of so many structures of the foot, it absorbs more than 15, 16 Joules. If you go to a shoe, a regular running shoe, it absorbs three to four joules.
Steven Sashen:
Oh my God. That’s brilliant.
Dr. Isabel Sacco:
Yeah. So our body solves the problem. We don’t need anything else besides our muscles, our tendons, our cartilages or ligaments. So coming back to the minimal issue again-
Steven Sashen:
Coming back to these old ladies in minimal shoes.
Dr. Isabel Sacco:
Yes. So we first tested if these shoes really absorb the impact in the knee. And what we saw a very interesting result because while walking down the stairs, in this task, we have more impacts than walking up stairs. So walking down and walking just walking, we reduced. We got the same level of knee loads as we were walking barefoot. And in some moments during gate, we call the middle. When we are with the whole foot over the ground and the other leg is swinging. So during this time we had a reduction in 12% comparing to barefoot. So the minimal issue was very successful in reducing loads even comparing to a barefoot, which we know it was the gold standard for loading absorption.
So after we confirmed that, after we confirmed that this shoe really works, we planned a randomized control trial, where we randomized 60 elderly women, two groups. One group walked for six months with the minimal shoe and the other group did whatever they used to do with their shoes, which were usually sport shoes, very cushioned shoes, because people like that and advised them to use that, even if there are no evidence that it works. I just want to mention, there is one paper from [Case Carrigan 00:20:08]. She compared this is sportive shoes with barefoot and she came across that it really increases the loads in the foot if you use those type of shoes and it can increase the progression of OA. So I don’t know why people or clinicians or whatever is to advise people with knee OA to use these shoes.
Steven Sashen:
I’ll tell you my theory. There’s two parts to it, but first I want … Well, okay, then I’m going to have a question for you. My theory is that, A, the idea of cushioning just seems to make intuitive sense. You sit on something cushioned, you lie on something cushioned, it feels good. And so we just assume that when you put something on your foot and it feels good because there’s that little bit of cushioning, that that must be good. What people don’t realize of course is that with that cushioning, it changes your biomechanics. It changes the way you move and your kinematics. And therefore that’s what’s leading to some of the force in addition to what you said before, where the cushion shoe just doesn’t absorb that much force to begin with.
But the bigger one is closely related. Two issues closely rated. One is that we’ve been hearing this story. Like I said, like the boy who cried wolf, we’ve been hearing this story for 50 years from companies that spend billions of dollars convincing you that this is true and there wasn’t a counter argument. And so now that that’s been going on for over 50 years, we’ve had two generations, over two generations, of people who believe this. And once you get past one generation, it becomes common knowledge. It’s just the way it is. And when people haven’t had another experience … Or I’ll say it this way. When they think they haven’t had another experience, they’re going to then use their own memory of their own experience to justify the belief from the advertising from these big companies. And I say they think they haven’t had the experience because you ask almost anybody, “Do you remember be …” Actually, I’ll tell you this story in a fun way.
There’s a former two-time world heavyweight champion boxer named Lennox Lewis. I had the pleasure of talking with Lennox on the phone a little while ago. He’s from Jamaica. And he said to me, “What do your shoes do for support?” I said, “When you were a kid in Jamaica, did you run around barefoot all the time?” He goes, “Yeah.” I said, “Did you have any foot problems?” He said, “No.” I said, “What did you do for support?” He said, “Nothing.” I said, “We do the same thing.” And it’s like, oh, so people have had the experience, but they don’t remember because they assume that that was a thing that you do when you were a kid, but as soon as you get into shoes, you clearly need them. And then it’s just you’re in an echo chamber because there was no other option.
Related to that, so our dear friend, Irene Davis puts on this event called the science of running medicine. And Irene does this amazing presentation about how regular shoes because problems and truly minimal shoes can cure those problems. This is all physical therapist. There’s 150, 200 physical therapists in the room. And I said to Irene, “After your presentation, everyone in that room should run and attack me and steal all of my shoes.” But they don’t. What happens is half of the room comes and checks out what we’re doing and only half of them actually get interested in what we’re doing, mostly the younger physical therapists. And I said, “One of the reasons is you can’t talk people out of what they believe with data. You tell people they’re wrong and it just doesn’t do any good.”
And the second thing is these people have, A, been wearing cushion shoes for most of their life and they believe that they’re good because they haven’t tried anything else. And they’ve also been recommending these to their patients. So for them to make a change would be such a massive shift in their own identity, let alone their identity in relation to their patients, that they just won’t go there. And the goal that I have, the thing that I try to do is, again, remind people of the experiences they’ve had that contradict what the shoe companies have been telling them. It’s like remember when you were a kid and you ran around barefoot and you feel the grasp between your toes.
My favorite thing to point out is I pull up a regular running shoe like I’m holding in my hand right now with a pointy toe box. And I say, “Is that the shape of your foot?” It shouldn’t be. And if it is, it’s only from shoving them into shoes that look like this, and why would you squeeze your toes together? If you’re going to drop and do pushups, you don’t squeeze your fingers together, you spread them apart. Same thing with your feet. And then people start to go, “Huh?” And so that’s, for me, that’s the way in, but people don’t … The research doesn’t do anything because people, they already believe what they believe. They’ve already spent so much money on the shoes that they have, that it’s just too much of a shift or it’s just not the way human beings process contradictory information. So, this is the challenge that we all have, is on the one hand, we want the research that you and many other people are doing to back up the story, but the research isn’t enough to make most people to make a shift. What we have to do that thing that makes them curious and then show them the research, but more than give them the experience.
Anyway, that was long but it actually leads me to the question I wanted to ask you. You saw that by getting people out of shoes and being barefoot. And then in this minimalist shoe, the the loading forces were reduced. If you could say something about what it is that actually reduces the loading forces. In other words, I’m going to poison the well by just baiting the question. Clearly what happens and what we’ve seen over and over and what I saw in the lab with the after Bill Sands is their gate changes. The way they move changes when they get out of those shoes. Can you say more about what you saw in terms of gate change that led to those reduced loading forces?
Dr. Isabel Sacco:
Yeah. So in this clinical trial, we measure foot biomechanics or foot and ankle biomechanics because they have to have the shoe on. We couldn’t measure exactly the 33 joint movements inside the foot, but what we saw was they … Because usually people with OA, they usually walk with the toes out to reduce the knee adduction moment. And also was a difference in the toe out. So they reduced the toe out walking. They reduced the rotation of the hips that is necessary to do this walking with the toe out. So, what we saw was a more natural walking pattern after six months of this shoe usage. So probably what we hypothesized is that they used more of those 25 muscles, 33 joints, 108 ligaments inside the foot to absorb the energy or to absorb the impacts. And also they changed the way they walked in a more natural way without doing any mechanical strategies to reduce the loads.
Steven Sashen:
Right. It just naturally adapted. The way I would have to say it is doing it wrong hurts, doing it right feels better. And if you have no choice, if you’re in a position where you can’t change your footwear in this case, your brain eventually goes, “Oh, you’re going to do that now. Well, then let’s make it a little easier. Let’s not put ourselves in pain.” And it subtly and slowly figures out how to move differently. To change that external rotation of the femur, to change the thing that points the toes out, clearly the thing that’s going to be doing that, or I’m going to … This is my hypothesis. The information they’re getting from their foot is coming up and changing the way they’re activating their glutes, because it’s the glute that allows that turning out or turning in.
And that’s really interesting, that just getting out of normal shoes can inform the body in a way that it starts using your glutes, which of course are the prime movers and let you move more naturally. And also, I know you didn’t study this, but also can be something that can very much help eliminate back pain because it’s supporting your lower back when your glutes are actually working properly. This is not part of the study obviously, but did you hear anyone make any reports about reduction in back pain?
Dr. Isabel Sacco:
No.
Steven Sashen:
Damn, that would’ve been good.
Dr. Isabel Sacco:
Yeah, it would be nice. Yeah. And if you were still in pain, if you could not do this more natural walking or if you are still using this stupid shoes with a lot of cushion, probably when you change the biomechanics of gate, you would change also the distribution of loads in other joints. So it might have a worse consequence for other joints too. So putting them in a natural, more biomechanical positive way of walking is also good for all the joints, not only the knee. And I just want to come back a little bit about what you were saying about why people still advocates this cushioned shoes for OA people. I think it’s of course a belief, a blind belief, but also the comfort guides us to choose our shoes. And we’ve been studying comfort and shoes for a while. And what we saw in a previous study with runners is that the comfort they feel doesn’t have anything to do with the impact while running.
So what we saw was in a study, we compare four types of shoes, of running shoes, very cushioned ones. Some of them were more, some of them were less cushioned. What we saw was the highest comfort was the biggest impact. And our mechanoreceptors in the plantor surface detects pressure, which is force divided by area-
Steven Sashen:
Surface area, right.
Dr. Isabel Sacco:
So if you have a larger area, because the shoes has an insole, very cushioned, that embraces your foot, you are miss … How can I say that? Your body receives the wrong information that because your mechanoreceptors detect less pressure. It supposedly reduces the impacts, but it doesn’t. So it’s only a perception of pressure, but not a perception of the impact. So we’re, how can I say that? I don’t really.
Steven Sashen:
It’s not misrepresenting, but misinterpret, not even misinterpretting. You’re just getting the wrong information. It’s the shoe-
Dr. Isabel Sacco:
Yes. You’re getting the wrong information.
Steven Sashen:
Wait, I want to slow that one down. So what you’re suggesting is that with a more cushioned shoe, the force that the bottom of your foot will feel is being dissipated enough, so the mechanoreceptors, those receptors in the bottom of your foot that are going to be detecting force, they’re not getting that information. And that information isn’t then being transferred up into your brain or into your spinal cord in the right way. And so the actual loading forces are the same. You just aren’t feeling it at that first point of contact.
Dr. Isabel Sacco:
Yeah. You are feeling like more distributed because the mechanoreceptors are sensible to pressure not to force. And the force is really what degenerate destructors. The force is the evil or the villain to our body.
Steven Sashen:
Let’s say this in a different way. So the cushioning is hiding the force by a reduced experience of pressure.
Dr. Isabel Sacco:
Yes.
Steven Sashen:
Yeah, yeah. So interesting you say this. Way back in the days when Hoka first came out, there were a number of runners that I know who switched to that shoe and they were going, “Oh my God, it feels so good.” And I said to them, “Oh, just wait.” And every one of them, two years later had knee problems and couldn’t run.
Dr. Isabel Sacco:
Whoa. Yeah. Why? Because then you were deceived.
Steven Sashen:
Oh, deceived. Yeah. Deceived is good.
Dr. Isabel Sacco:
Deceived. So you were deceived by the pressure detection from the mechanoreceptors.
Steven Sashen:
Interesting.
Dr. Isabel Sacco:
And what we saw in this paper from my PhD student like five years ago, we saw that the highest comfort produces the highest impact peak depending on the shoe. And people go to the store and look for the more comfortable shoe, not the more effective shoe for absorbing impacts. So this is the first probably problem that we see there. Maybe this is one of the reason that even if there are many scientific evidences proving that the cushioned shoe doesn’t solve problems like knee OA, they keep advising to use that. Not only because they believe as a religion, but because they feel more comfortable and they think comfort-
Steven Sashen:
You nailed it. If you’re a salesperson and somebody can walk in and try on a shoe and go, “Oh my God, that feels comfortable,” it’s an infinitely, easier sell. And so let’s just say a lot of the people on the sales floor who don’t know any better are looking to sell shoes. That’s their job. And the easiest way to sell something is to give people an immediate experience of comfort even if that comfort is demonstrably bad for them.
Ironically we have this happen all the time. When people come into our office and try shoes on, the first thing they get is the comfort of having their toes not squeezing together. So they feel that comfort. And then they also get the comfort of having their posture realigned because they don’t have the elevated heel. And then they walk around and they get the added comfort of actually feeling their foot moving. And we’re on a very … So basically they’re getting the comfort of being close to barefoot. For anyone who likes barefoot, they’re getting that experience and they experience that as comfortable. And then they start walking around.
My favorite thing is someone will say, “Well, don’t I need arch support?” And I say, “Well, I don’t know, you’ve been walking around for 20 minutes. Do you feel like you need arch support?” They say, “No.” I go, “Eh, then you don’t.” And of course they don’t, but to your point, and again, it’s like getting on a mattress. A really, really comfortable mattress is not necessarily the one you should sleep on because it could put your joint in positions that are problematic if you’re spending eight hours a day in those positions.
This is going to sound strange maybe. We are wired to look for comfort for a reason clearly. It’s an evolutionary thing. One of the things with our sandals, which one? Oh yeah, it’s up there. That pinkish one. So Z trail sandal, the amount of foam in that is very small and it compresses a very tiny amount, maybe half a millimeter, maybe a millimeter tops. And when people put it on, they talk about how comfortable it is. And in my mind, I’m thinking, something that compresses that small amount is not super comfortable technically, but people experience it as being very comfortable.
So it must be, this is my hypothesis, that at some point in our distant, distant, past that little bit of cushioning, that tiny bit of give must have signaled to us something good is nearby, food, water or shelter, something. Somewhere good to sleep, who knows? Because it doesn’t make sense from a Physics standpoint, if you will, that that tiny amount of cushioning creates that feeling of comfort. And so there must be a reason. And if we just extrapolate from that, again, there must be reasons that we prefer certain kinds of comfort over what’s better for us from some mismatch of evolution and our current lifestyle.
Dr. Isabel Sacco:
Yeah, yeah. Probably, probably. And Steven, I just want to finish the study-
Steven Sashen:
Oh my gosh. I know. That’s what I was going to say next. Let’s go.
Dr. Isabel Sacco:
Yeah. So then what we saw after six months is we saw a reduction in 62, 63% of pain, they start using less painkillers medication a lot, significantly less painkillers. It improved 66, 60 7% in function. So they were much better. And when we measured the need joint torque, that impact, it reduces 15% in six months of usage. So it was a very amazing result-
Steven Sashen:
Well, let’s get to that part. I’m assuming you x-rayed them again at the end of that six months, yes?
Dr. Isabel Sacco:
Yes. Yes. But then because the x-ray is a very simple measure, we could not see the damage in the cartilage. We had to do a different XM, an MRI with contrast. Then we could see the cartilage. This is a future study that I wanted to do to see the changes in cartilage. But we know from literature that reducing loads reduces the progression of OA. And in the same six months, the control group that kept using the cushioned shoes, they increased 25% in the impact peak of that knee joint. So they for sure will progress more rapidly comparing to the intervention group.
Steven Sashen:
Do you have a theory about why they saw the progression in load? I have one. I want to hear if you have one.
Dr. Isabel Sacco:
Go ahead.
Steven Sashen:
Mine is these are elderly women. And again, something I referenced before, so as we get older, we start to lose muscle mass, we experience sarcopenia. And so if the reduction of impact is not contingent on the shoes, but is about the soft tissue providing force reduction, as we’re getting older and we start to lose muscle mass, we have less muscle mass to provide that protection. So that would lead to the ongoing progression that is just coming, quote, coming from just getting older, which of course is not that. It’s just the function of getting older and losing muscle mass, which that one is very hard to do anything about along with having the shoes that are increasing the loading forces. It just becomes a vicious circle.
Dr. Isabel Sacco:
Yes. Yes. It’s a vicious circle because when you use more support by the shoe for example, you will need less input from your muscles. So then you use more support because you have less and less strength, less and less functionality. So then you are trapped. You are caged to this condition. It’s a very bad situation.
I just want to share just one more study that I just finished, and is publishing American Journal of Sports Medicine. We trained the foot of runners and we know runners are well trained. They have a lot of strength, flexibility. So the gain that we can have with this population is very small, but we trained the foot. And usually they run with a very cushioned shoes and they run with cushioned shoe. We didn’t change the shoe, but we changed the way they use the foot inside the shoe or outside the shoe while they are doing daily living activities. And after a year of this practice, they reduced 2.5 times or fold, I don’t know, the injury rates. And we studied 120 runners, recreational runners. And after 12 months, they were less injured in 2.5 times compared to the control group..
Steven Sashen:
This is brilliant. You’re going to love this. We have a couple of professional hockey players who are wearing Xero shoes who called us to say, “We’re skating better because our feet are getting stronger from wearing your shoes when we’re off the ice and out of those boots that don’t let our feet move.” And that seems so counterintuitive. You’re basically showing the same sort of thing. So, what did you have these people doing for foot strengthening that led to this impressive result?
Dr. Isabel Sacco:
Yeah. We selected some exercise that are very common. The short foot, the arch, the arch elevation, the adduction abduction. We used some small to increase the resistance of the shoe. This thing that people use for nail polish. Yeah. They squeeze.
Steven Sashen:
Oh yeah. So for people who can’t see, so you have … If you’re getting a pedicure, they put these little sponge things to separate your toes. Instead of just having them separated, you use that to have them squeeze in. Oh, that’s brilliant.
Dr. Isabel Sacco:
Yes. So we use that. We use also elastic bands to open and to abduct the fingers. So it was a program of many exercise. We have around 30 exercise, different exercise. And we progress the exercise as the runner evolves in the training. They were training once a week with a physical therapist and other three times alone with a software that we developed. So they followed the exercise regime for eight weeks, then we measured them eight weeks before and eight weeks after to evaluate the foot biomechanics. And it changed a lot. We did also MRI to see that if the muscle increases in cross-sectional area and increases in the strength, we use the test to test the foot muscles, the strength, and we followed them for a year to measure the running injury incidents. It was an amazing result-
Steven Sashen:
That is incredible.
Dr. Isabel Sacco:
And just for them to use the foot, use your foot.
Steven Sashen:
Oh my God, that is brilliant. Well, obviously what you did, what you need to do is you and Sarah Ridge at BY, you need to get together, because every study is showing walking in minimal issue increases load. But she didn’t do, and she had the exercise program being separate, and she didn’t do combining the exercise program and the minimal shoes nor did you. So you had the exercise program in regular shoes. That’s the study we have to do next, is putting those two things together and see what kind of result we get. Pardon me. Excuse me. Oh my God. I can’t wait. So when is this study being published?
Dr. Isabel Sacco:
It’s already. It’s published this last year in American Journal of Sports Medicine. It’s an amazing paper. You have to see.
Steven Sashen:
I feel remisce that I somehow missed it, but, A, you’ll have to point me to it. And B, what’s happening with software, are you making that commercially available?
Dr. Isabel Sacco:
Yeah, it is. It’s free public. And you can use the Google Translator to use. It’s already translated to Portuguese, of course, English. But if you use the Google Translator tool, you can use in German, in whatever, in Polish. I know that the Brazilian, the Brazil … The German Society of Diabetes, they are using our software already to train the foot of diabetic patients because we train also diabetic patients, the foot of them. And we saw a reduction ulcer incidents after a year doing just foot exercises.
Steven Sashen:
And I’m guessing a big chunk of that is just increase in circulation.
Dr. Isabel Sacco:
No, it improves the musculoskeletal condition. And then you use your foot more properly and the foot fall over during gate changes, and the distribution of pressure changes. Because the main problem of ulceration is the mechanical loads. If you change the way you roll over your foot, you change this risk factor and then you reduce the incidence of injury. And also in diabetic patients, if you have a muscle atrophy, which they have, and also deformation of the joints to a clots or those type of things, you also increase the pressure because of this deformation. So if you improve the condition of the foot, if you increase the strength, if you realign the joints, you reduce the chance of an ulceration.
Steven Sashen:
So, this is going to sound perhaps silly, but I’m getting a little teary eyed. And the reason-
Dr. Isabel Sacco:
I saw.
Steven Sashen:
Yeah. And the reason why, oh, man, this is affecting me in a big way. On the one hand, it’s painful to me that the people who are doing this incredible were you, for example, that this information isn’t out there and making a difference. That’s painful. But what has me teary eyed is the opposite of that. Those of us who are exploring natural movement in the different ways that we’re doing it, and hopefully supporting each other in the process, when people say, “What are you trying to do at Xero Shoes,” I go, “Nothing special. Just change the world.” And it’s just fun to say it that way. But what you just described is part of a thing that will change the world. If we can get enough people to have this experience and understand it, it can change the world.
It’s not like I didn’t know this, but it’s just hitting me at another or level. Because when you start to bring in things like diabetic patients, where many people think that there’s just nothing to do for them, or again, put them in big thick cushion shoes so they don’t use their feet, which just makes things progressively worse. It’s such a big deal. In fact the only other time I got teary eyed like this now that I think of it was when Irene Davis said to me, “If we to get kids wearing shoes like yours, in 20 years, we won’t have to treat adults for the billions of dollars of problems they currently have.”
And we’re up against a mountain of propaganda from big footwear companies and a mountain of common knowledge from just, again, the 50 year history of this. But the difference is we can … This is like, you weren’t there, at the American College of Sports Medicine a couple years ago. I was on a panel discussion with some guys from Brooks and Adidas and our friend Tony Post from Topo. And the guys from Brooks and Adidas were saying, “Well, we don’t have any research to prove that we can reduce injury and improve performance.” And I said, “We do. On our end, we do.” And it still didn’t really register with people.
And I know, look you’ll like this, we’ve had the CEOs of two multi-billion dollar footwear brands and a senior vice president of a third say directly to friends of ours or a friend of ours that this whole idea of natural movement is legitimate. They said, “We can’t do it though because it would be admitting everything we’ve said for 50 years is a lie.” So if we can overcome that hurdle, get a top of that mountain of lies and start skiing down the other side, this will change the world.
Dr. Isabel Sacco:
Yes. It will. It will definitely. And some of the research that we did with diabetic patient now is inside a guideline for prevention of ulceration. So since 1995, they published every four years a guideline to guide clinicians to prevent ulcerations. And for the first time, in 2019, two years ago, they published a new guideline and now the foot related exercises are there to prove that we can improve sensitivity. We can improve range of motion, we can improve strength, and we might reduce the incidence of ulcer because this paper, or this clinical trial that we just finished proved that we can reduce the incidence of ulceration.
And Michael Miller from Washington University. He also proved two years or no, some years ago, that also the incidence of ulcer did not increase doing foot related exercises. And when we use a minimal shoe, we allowed the joints and the muscles to exercise. And Sarah Ridge already proved that if we use a minimal shoe, the condition, the musculoskeletal condition of the foot improved, so maybe we can connect that. We just published, I had the honor to be part of this paper written by Danielle, Irene Davis, Sarah Ridge, myself and Scott, where we discuss about the minimal shoe. I don’t know if you saw this paper.
Steven Sashen:
I did see that one actually.
Dr. Isabel Sacco:
Yeah. And we approach those topics. I discuss about diabetic patients. We have to do some research using minimal shoes in this population. We first do exercises, but maybe the step, we’ll be testing minimal shoes for people not in a risk for ulceration. So people with neuropathy, but not with a history of ulceration. Because if you already have a ulcer, you have 40% chance of re-ulcerate. So the re-ulceration rate is very high. Probably people that hasn’t ulcerate yet, we could use this strategy.
Steven Sashen:
Some people ask me why people like you and Irene, et cetera, are studying minimalist footwear instead of barefoot. And Irene had the perfect answer, which is because most people aren’t going to go barefoot. And similarly, in this study, you just mentioned, and the paper you just mentioned, presenting the exercises is an easier way in for people than saying, “Hey, you have to do these exercises and switch your footwear.” So, we want to meet people where they are and give them a little nudge to the next step and the next step and the next step. That’s the easiest way to make massive change.
And again, in fact, I’m reading a book about this right now. I can’t even remember what it’s called. I just got it from the library, but it’s all about … It’s from the work from Robert Thaler about behavioral economics and how making people change requires small incremental steps. Because if they’re small and incremental, you won’t even notice. It’s not a big intervention. And then eventually you end up with a big intervention when you add those all up. And yeah.
So that’s the thing that I keep thinking here, is at a certain point, this natural movement idea is going to hit that critical mass, where we’ve taken these little steps. And again, that’s the … Now I’m getting chills instead of crying. That’s the change the world part. And I got to tell you, honestly, one of the things that I say is I just hope I’m alive to see it. So, I’m going to be 60 years old soon. I don’t know how long I’m going to live. Thanks to the internet, information travels faster than it did before, but it takes a while for people to make changes. So, I hope I’m alive to see it.
Dr. Isabel Sacco:
Yeah. Changing paradigms is very hard for people. In science, I think it’s easier because we have data. We are convinced by the data. But I think in a common sense, it’s more difficult to prove.
Steven Sashen:
Did you see the article? It was in the Washington Post that was featuring Irene Davis and [Jay Dasherry 00:53:46], and talking about how regular shoes could be detrimental for kids’ development and for elderly people for things like balance and agility. And it couldn’t have been more cut and dry. Here’s the research, here’s the information, here’s what we’re saying. But of course in every article like that, they have to have people who argue against it. They have to make it quote fair and balanced. So they brought in three people to argue against it, but the arguments had nothing to do with what Irene and Jay were saying.
But this is another thing that allows people to continue believing things that are factually inaccurate, is that the people who are reporting think that they’re doing a good job by presenting a counter opinion even if the counter opinion is a straw man or a nonsequitor or any other thing that is really not a counter opinion or a counter argument. It’s a counter opinion and the opinion has no weight. That’s another issue as well. And again, hopefully the internet can address that because if we are presenting the information, we don’t need to bring in somebody who argues with us.
Dr. Isabel Sacco:
Yes. Yeah.
Steven Sashen:
At the same time, it’s a fantasy of mine. I haven’t had anyone on the podcast yet who thinks I’m completely full of shit. And I want one of those people to get on the podcast. Now I have to be careful, I will admit, because there’s one or two people that I know who I would love to talk to, but I’m well versed in the ideas of the research. I’m a globalist. I don’t do specifics as well. And they’re very well versed in this specifics. And so if they just start saying, “Well, the following research …” and they misinterpret it, or they use it to their own advantage, I won’t be able to counter that in real time because I won’t know the research well enough to go, “Well, hold on.” So it’s a bit of a challenge, but ironically-
Dr. Isabel Sacco:
Maybe five people, maybe you do a debate, I don’t know. It would be easier.
Steven Sashen:
It’s so funny you say that. This panel discussion at the American College of Sports Medicine. So me Tony Post, and for people who don’t know because I’m sure they don’t, Tony Post was the CEO of Vibram. When the five fingers took off and now he has his own company and he totally believes in natural movement. And then the guys from Brooks and Adidas. That was the most well attended event they ever had. It was literally standing room only. People, they packed the aisles. And it’s something that I’ve wanted to do, is to go on tour. Not just me, me and you, you and Irene, any combination of the people who are doing this research who know it well. But I want to include myself just because as a former standup comic, sometimes I can make the points in ways that people get faster, but regardless we get the pro natural movement and the anti natural movement people. And we go on tour.
The only problem with this idea is the people on other side of the argument, they have to have egos the size of Mount Everest because we will destroy them. And they have to be able to handle that maybe, maybe by getting paid enough. They have to be willing to just be the battering or whatever the other side of a battering ram is, whatever you batter with a battering ram, because that’s what happens. Because they have no research that that leans in their favor. Or the research they have that seems to air in their favor is so flawed. It’s unbelievable.
The one example I like to give is some research done here at the University of Colorado was done with, quote, accomplished barefoot runners. And I said to the person who did the research, “I know all the barefoot runners in town. I’m one of them.” And neither I nor anyone I know was involved in your research. I know the people that were in your research, they’re not accomplished barefoot runners. They’re accomplished runners who spend a little bit of training time running barefoot on the grass, completely different thing. And yeah, I said, “By the way, the University of Colorado lab is sponsored by Nike. Not saying that means everything, but it’s important to know that.”
Dr. Isabel Sacco:
Yeah. Yeah. Yeah, yeah. And in the academia, there are a lot of vanity, so people are vane a lot. And yeah, you have to break paradigms to be a good scientist. You have to be flexible to help people or to change this status quo of a lot of things. We have to be flexible. We have to suspect of what we believed so hard because otherwise science won’t advance-
Steven Sashen:
What you have to be willing to do is investigate something to prove to see if you’re wrong, not to prove that you’re right. And the point you made at the very beginning of this conversation was that the cushioning did not reduce loading forces was surprising because you thought that it would. Everyone who did that research, Christine Pollard tells the same story, we thought we would see decreased loading forces with increased cushioning. We were surprised to see that it wasn’t the case. And so that thing of like, “Let’s take a look,” and be will to find out that the data disagrees with what we believe and then change our mind because of that, this is a very powerful thing. And it’s, again, people who aren’t doing their own research or don’t understand research don’t understand or don’t do or people will rely … They’ll misrepresent their own experience if they don’t have research to hold onto the thing they believe. This is just human cognition. It’s just what people do.
Dr. Isabel Sacco:
Yes, yes, yes. And you know about this and the OA study.
Steven Sashen:
Yeah.
Dr. Isabel Sacco:
We were invited for a big show in the biggest network television in Brazil, which is Global News. The program was about pain and we were there for like an hour and a half describing our study and other studies. And this might be part of that baby steps to convince people. I also am being invited for some conferences, some lives that maybe people would at least suspect that maybe their beliefs, their previous beliefs are not that true. And I think we are … For example, this initiative of the international working group on diabetic food was an amazing initiative and based on studies. And now about this amazing paper that we did for five years, we finished our study and it’s published that the hazard ratio for injuries reducing 2.5. I think people will start and at least some groups, and then these groups will talk to the others. And then we can have a wave of changing. It will be slow, but I think we are doing something.
Steven Sashen:
I usually talk about this from two angles, but I think there’s three angles or three points of a triangle, if you will, that are responsible for the change. One is just that grassroots thing of people having the experience and changes their lives and they share that. Another is highly influential people who have the experience who have higher reach, professional athletes, for example. And the third of course is the research. And they all work together as there’s the grassroots component, there’s the top down component. And most importantly, the research, again, I’m going to contend that it won’t be the thing that drives the change, but it’s going to be the thing that once people … It’s like after you buy a red car, all you see is red cars. When you have the information behind you to explain and understand the experience that you’ve had, then that’s really powerful.
If you’re just trying to give people information, that doesn’t do it. But if you have that as the backup, in fact, it’s something that we’ve been trying to do, is trying to guide people on how to talk about the experience they’ve had from wearing Xero shoes so that they don’t meet resistance or create resistance, but invite people into the questioning, into the curiosity. And then here’s all that information that allows them to find out more.
And frankly, it’s something we need to do better on our end. It’s something we need to do better on our website and in the communication we have, and this is something … It’s a project of ours. And to that, on that note, all the studies that we talked about here, we’re going to have in the show notes, and we’re going to be adding those to our website and same thing with the software that you described. We’ll definitely put a link in for that as well so people can experience that. It’s all of these things together. I agree with you that eventually it’s going to have to make a difference because it makes a difference. If what we were talking was just marketing bullshit, it wouldn’t matter. But when people have these experiences, you can’t … And it’s not just their perception of a change, it’s demonstrable change. The research backs up. That’s our only hope I think.
Dr. Isabel Sacco:
Yeah. And this initiative here that you do with your podcasts are amazing. I think it reaches more people. And yeah, they inform people in a different way, in a way that people like.
Steven Sashen:
I think about it, and there’s certain design ideas. There’s a particular car in America. There are a couple cars in America that when they first came out, people didn’t like the way they looked. They were very polarized. People either loved them or hated them. And that polarization created a conversation. And over time people got used to the design because they’ve kept seeing it. And so they weren’t as polarized. And then the company made the design less polarizing and more acceptable to more people. I’m sure there’s some version of that, that we can all do, where we create the polarization even bigger than it is right now. And then once people get used to it and more and more people have the experience, it won’t be as crazy. And then things get toned down a little bit. There’s nothing for us to tone down because we’re already doing the most you could do.
Dr. Isabel Sacco:
Yes. Sure. Yeah.
Steven Sashen:
Anything else that you can think of that you wan to share, anything that it’s coming up that you’re working on that’s exciting for you?
Dr. Isabel Sacco:
I think this software that it’s free in public. You can download in the Android for, just for Android in the Play Store. I have to have fundings to go to the iPhone as well. I think it’s a good start.
Steven Sashen:
Hold that thought. How much do you think it cost to make the iPhone version, the iOS version?
Dr. Isabel Sacco:
We need 10,000, which is, I think, $2,000. Something like that.
Steven Sashen:
That’s it?
Dr. Isabel Sacco:
Yeah.
Steven Sashen:
We need to talk.
Dr. Isabel Sacco:
Okay. Thank you. Yeah, we need to … Yeah. And I think it’s a good thing for people to start because it’s a very friendly environment. It is a software because it has an algorithm behind. Because you give a score to each exercise you do, so th
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