Have you ever wondered why changing shoes helps for a while, only for the same pain to come back? This conversation will change how you think about feet, form, and “support.”
In this episode of The MOVEMENT Movement, Steven Sashen speaks with Jae Gruenke, Certified Feldenkrais Practitioner and founder of The Balanced Runner™, who explains why many runners stay stuck in pain even after new shoes, inserts, or medical treatment. Often called the “wise woman of running,” she’s helped runners and triathletes, from beginners to Olympians, improve performance and resolve chronic issues through neuromuscular reeducation and movement learning. Together, she and Steven Sashen unpack the cushioning vs minimalist debate and reveal the overlooked forces and compensation patterns that determine whether your stride feels easy or keeps fighting you.
Key Takeaways:
→ Your nervous system governs movement choices, often limiting range and load as a protective strategy.
→ Improved coordination reduces effort and unlocks “already-there” strength.
→ Foot soreness on pavement isn’t automatic. Pain can signal excess horizontal force, not the hard ground.
→ Chronic pain often creates compensation loops, making people double down on the pattern that caused the problem because it feels safest.
→ Movement reeducation can reveal the true driver of your chronic pain.
Jae Gruenke is a Certified Feldenkrais Practitioner, running technique expert, and founder of The Balanced Runner™. Often called the “wise woman of running,” she helps runners and triathletes—from beginners to Olympians—relieve pain, move more efficiently, and improve performance, especially when issues persist despite medical treatment.
A former professional dancer, Jae studied modern dance at Bennington College and Williams College and performed with New York City-based companies for more than a decade. Her work with choreography that required sustained outdoor running sparked a deep study of running mechanics, using her Feldenkrais training to make running feel easier and more enjoyable—then teaching those principles to others.
Her work has been featured in outlets including Runner’s World UK and the Minneapolis Star-Tribune, and she contributed to Dr. Mark Cucuzzella’s 1-2-3 Run program for the US Air Force.
Connect With Jae:
Website: https://www.balancedrunner.com/
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Episode Transcript
Steven Sashen
Cushioning is a big debate in the barefoot minimalist world and in the super maximalist world and everything in between. And we’re going to take a look at that because there’s a lot of misinformation, a lot of confusion, a lot of questions that haven’t been asked, and a lot of people, frankly, who have a case of cranial rectal reorientation syndrome whenever they bring up the topic and talk about what they think about it. So we’re going to look at that on today’s episode of the Movement Movement podcast for people who want to know the truth about what it takes to have a happy, healthy, strong body, starting with those things at the end of your legs called your feet. And we also break down the propaganda, mythology, and sometimes the outright lies you’ve been told about what it takes to run, walk, play, do yoga, CrossFit, play pickleball. I hear that’s a thing. Or whatever else it is you like to do and to do those things enjoyably and effectively and efficiently and. Did I say enjoyably? Don’t answer. I know I did. I put it out there first, but I always keep it in there because if you’re not having fun doing whatever you’re doing, you’re not going to keep it up anyway. So make sure you’re having a good time. We call this the Movement Movement because we’re creating a movement about natural movement. And when I say we, that’s all of us. And you don’t have to do anything special. It’s, you know, the usual, give us a thumbs up, like, share, comment, et cetera. In short, if you want to be part of the tribe, just subscribe. Because the way this whole thing is moving is from people who have the experience of natural movement, letting your body do what it’s made to do without getting in the way and causing problems. They’ve had these great experiences and they tell their friends and they tell their friends and they tell their friends, and it’s like shampoo if you know the reference from a commercial from when many of you weren’t alive. Okay, so I’m Stephen Sashin, co founder and chief barefoot officer here at Xero Shoes. And just a quick reminder, feel free to jump over to www.jointhemovementmovement.com where you’ll find all of our previous episodes, other ways you can find the podcast if you care, and ways you can find us on social media as well. So, all that said, let’s get started. Jay, you’re one of the few people who is now Making a repeat appearance on the podcast. But for people who didn’t see you the first time. Oh, you’re this number three. Oh, you’re the winner. Holy crap. Tell people who you are quickly, and then let’s just jump dive right in, shall we?
Jae Gruenke
Sure. My name is Jay Grunke. I’m the founder of the Balanced Runner. So I’m a Feldenkrais practitioner, which means that I’m a movement educator these days. I’ve finally been talked into calling myself a running form coach, but that’s not. It’s not really the format for the. The kind of improvement that I help runners make. So.
Steven Sashen
Wait, I’m going to interrupt you because I. So, for people who don’t know, Feldenkrais is a really fascinating body work method, for lack of a better term, that really focuses on neurology. Basically, your brain is what can control how you move. And often the movement patterns that we have or limitations that we have, that some are good, some are bad, are mediated by your brain and what Feldenkrais does. Because I did this with some of the people who brought it over 30 plus years ago. It basically starts by retraining your brain about what you can and can’t do in a way that produces some really dramatic, really rapid results. Like magical sometimes, not always, but sometimes. Like you literally can’t believe what just happened in just a couple moments. So I just wanted to. So I like when you say move an educator, I was thinking it’s kind of uneducating or re educating is what popped in.
Jae Gruenke
Yeah, yeah. If we’re. If we’re forced to write up something for somebody’s insurance or HSA or whatever, it’s neuromuscular re education.
Steven Sashen
Right. Okay.
Jae Gruenke
Sorry. Yeah. But that assumes you knew it to begin with.
Steven Sashen
Right.
Jae Gruenke
Which you may not have.
Steven Sashen
Well, no, you may not have. But I mean, my favorite story, my favorite Feldenkrais story ever. And it actually came from the guy who brought Feldenkrais to America named Tom. Hannah was a woman who came to him who said she couldn’t lift her arm above her shoulder height. And he said, oh, that’s really weird. Do me a favor. Can you, like, bend over at your waist so your upper body is parallel to the ground? And she goes, yeah. And he goes, lift your arm as much as you can. And she lifted it, not thinking till it was parallel to the ground in line with her body. He goes, now stand up. And there’s her arm pointing straight up to the ceiling, which she said she couldn’t do. And then suddenly she could. And it was literally just telling her brain, no, no, you can do this. And wait, I want to interrupt with this idea and go with it a little bit longer because this might impact, pun intended. What we’re talking about, about cushioning, I see this all the time with runners who are in big, thick, elevated heel shoes who basically are training their brain that their Achilles can only stretch a certain amount.
Jae Gruenke
Right.
Steven Sashen
And then when they get into a minimal issue, they go, oh, I gotta, you know, I had some Achilles problems. Like, no, no, no. What you did is you didn’t take the time to teach your brain or reteach your brain or unlearn or however you want to think of it, that it’s safe to do that thing. You’re. You’re basically setting up a fight between what you’re trying to do with your body and what your brain is telling you you can do. And you. There’s easy ways to get around that. And I see it all the time, so it’s one of my favorite.
Jae Gruenke
You always lose that fight too. But.
Steven Sashen
Yeah, well, you know what? But I thought, I thought of a funny example, like an upside down example about this and I mentioned it on a podcast, I think, right before this one, where I remember watching a video from a TV show called something. I don’t remember what it was called, but basically people who, like, survive these life and death things. And this is a guy who’s hiking on a mountain and the side of the mountain came down and like a giant piece of granite landed on him. And he’s on his back on the trail with like £2,000 on him and thinking he was going to die, he literally bench pressed it off and made it down. And once he got down and the shock wore off, he had ripped like every muscle and tendon in his upper body because basically all of those things that your brain is saying, don’t do that, just shut off. And he overwhelmed and overloaded the tissue, which is something that, you know, your brain is telling you not to do.
Jae Gruenke
Yeah, yeah.
Steven Sashen
Anyway.
Jae Gruenke
Oh, so many enticing directions, even I could go from there. And we never end up talking about
Steven Sashen
cushioning, but let’s talk about.
Jae Gruenke
Yeah, but I can’t resist just saying about speed. Speed of change is, you know. Yeah. Your brain is always protecting you from using your max just in case a boulder falls on you. Right. It wants you to have something left in the tank. So. So this is why, or this is a key reason why it’s possible to get a huge improvement and a Huge change in your running form without needing to do a lot of strengthening either prior or afterwards to be strong enough to hold the form. It’s like, well, first, more coordinate, coordinated movement is easier, not harder than less coordinated movement. So we may be shifting the load, but we’re also reducing it. But second, it doesn’t take that long to build strength in previously weak muscles because there was already more strength there.
Steven Sashen
Right.
Jae Gruenke
And when the signal is given that and your, your, your system recognizes it, it’s like, oh, no, this really works. The strength is closer to sufficient than you thought.
Steven Sashen
We see this all the time with people who’ve been wearing arch support and basically immobilizing their foot and their foot progressively getting weaker. There’s research from Katrina Protopapa showing that just putting inserts in the shoes of healthy ATH reduced foot strength by up to 17% in under 12 weeks. And of course, you know, that continues not forever, it’s asymptotic, but to your point, you know, when people say, well, I’ve been wearing these, this stuff, all these like big stiff shoes for many, many decades, it’s going to take me forever to build strength up again. It’s like, no, no, no, way faster than you think. And research on that shows, you know, significant progression in anywhere between six and eight weeks. So. And, and you can always get more and more and more, but to be sufficient takes much less than what people think.
Jae Gruenke
Yeah, when people do my six week online course, they come in, in orthotics and usually they’re out of them by the end.
Steven Sashen
Yeah, yeah, yeah.
Jae Gruenke
So, okay, so cushioning. So I’ve been thinking a lot, like, I don’t know if this is true for you, I’m very interested to hear, but I feel like in the last year I have come across a number of people with platforms talking about having been in minimalist footwear for a long time, but discovered that they really actually feel that they do better with some cushioning.
Steven Sashen
Okay, better, do they say better? In what way?
Jae Gruenke
Well, I mean, fundamentally it’s more comfortable.
Steven Sashen
Right, got it.
Jae Gruenke
And they prefer some cushioning, which blew my mind because I’ve been in minimalist for like, I. And even as long as. So I got my first pair of vivobarefoots around the time my son was born. That was 2009. So, yeah, early days. And I never want the cushioning.
Steven Sashen
Yeah. You know, it’s funny, I’m testing a product right now. I have our normal insole in this particular shoe on my left foot and the one that they Provided me in my right foot and it’s maybe a half a millimeter thicker. And I not only feel the difference, but I’m not crazy about the difference. Now, that said, I go through this thing, especially in the summer, where if I’m like, literally barefoot, or in our genesis sandal, which is just four and a half millimeters of rubber, and then I switch to our trail sandal, the Z trail, which has like, I don’t know, I think it’s about 8 millimeters worth of something. You know, stuff to protect you from the rocks and et cetera, et cetera. I definitely feel like I’m kind of on vacation when I’m wearing that shoe or the Z trail. And then when I go back to something, quote, more barefoot, it’s like, oh, I can feel things again. So there’s definitely kind of a, you know, a little bit of a push me pull you. That sometimes something feels better, sometimes not so much. But whenever people make comments like that, and I don’t know that I’ve heard that I’m hearing more of them. I hear that people are being a little more. How do I want to put it? Activity specific. Like, what happens to me? Often I’ll be in the airport and people will go run up to me, like, oh, my God, it’s you. And then they’re not wearing Xero shoes. And they go, these are the things that I wear when I’m rushing through the airport. It’s like, right, so let’s say, you know, use case specific. I found that people are making some changes based on that. And my response is, cool, do what works for you. Not. I’m not going to argue, but I. I am curious about why, you know, what they’re doing. Like, if I had my way, I’d say, do me a favor, let me take a video of you walking or running or doing whatever it is you think you’re doing when you’re wearing these shoes that makes you think you need these to see if I notice anything interesting. And I. There’s a bet that I would place that I would notice something interesting.
Jae Gruenke
Yes, you would. So would I. And in fact, the airport. The airport gets us right to what I want to talk about.
Steven Sashen
Oh, cool.
Jae Gruenke
Because I had the pleasure of studying with the master animal tracker, Richard Vaca, Point Rey’s tracking school, California. Anybody who’s out there, you gotta. You gotta study with Richard. It’s amazing. I’m not sure I attained a level I would even call beginner. It’s such an incredible, sophisticated, you know, lifelong. I Don’t know. Practice and coming into it, you know, as a modern human living not out there where it matters anyway, that’s a whole other thing. But like so, so when I was studying with him, I learned one of the fundamental things you look at in animal tracking is what are called pressure releases.
Steven Sashen
Okay.
Jae Gruenke
So that’s where the, that’s where. And how the ground gives way or shifts in response to the pressure of the print of the, of the foot against the ground and is the same whether you’re tracking non human animals or human animals. Right. It’s like there’s no different rules for people. Okay. But we weren’t out that we were drag king coyote and otters and bobcats and things.
Steven Sashen
Well, I was gonna say bobcat’s different when he’s. For the first two, it’s like if you stumble upon one, it’s not a big deal. For the third one it could be, you know, a little, little twitchy.
Jae Gruenke
Yeah. So. Yeah, but not so much.
Steven Sashen
No.
Jae Gruenke
I mean, well, especially when it’s in its own habitat like a, like also you’re not going to come across one in its own habitat. It’s going to melt the way. Unless it wants to talk to you. But the. So pressure releases are. They tell you they’re, they’re a profoundly rich source of information and they happen throughout the print. I’ve actually just been going back. I’m amazed at how much I’ve forgotten about pressure releases in the last few years.
Steven Sashen
Let me, let me, let me start with this with kind of a simple one for people. To some people, again, people who are old enough to get my shampoo reference are going to get this. So the whole idea behind Earth shoes back in the 70s and 80s was here’s what it. Look what your footprint looks like in the sand where your heel ends up lower than the rest of your foot. So we’re making a negative heel shoe to accommodate what they were calling natural. So that’s an example. Arguably.
Jae Gruenke
That’s interesting. I didn’t know that was the inception of it.
Steven Sashen
Yeah. The negative heel was, was totally based on that.
Jae Gruenke
Yeah. Although that is not technically a pressure release.
Steven Sashen
True. But I, but I, but I have a sneaky suspicion some people are going to have that thing in the back of their head.
Jae Gruenke
Yeah.
Steven Sashen
And so I wanted to address it. Yeah. So let’s talk about the distinction between this because first, it’s definitely not a pressure release.
Jae Gruenke
Right.
Steven Sashen
No question.
Jae Gruenke
Right. It’s, it’s, that’s like the depth and shape of the print which tells you I mean, that’s also relevant. In fact, I have a picture. So this is not gonna help so much the people who listen and. But I’m one of the people who listens to this podcast, so share.
Steven Sashen
Share it and then we’ll describe it.
Jae Gruenke
Okay.
Steven Sashen
But then this is also a good excuse for people to go to the website or the YouTube page.
Jae Gruenke
So.
Steven Sashen
Okay, so.
Jae Gruenke
Right, so this is a. This is my Zoom. The sharing bar is always right over what you want to look at.
Steven Sashen
I know.
Jae Gruenke
Okay, so here are some. These are dog prints. Prints, like domestic.
Steven Sashen
Yeah.
Jae Gruenke
Or. Well, let’s see. Okay. The ones on the left are dog prints. The ones on the right are a diff. They’re. They’re. Now they’re probably a dog, too. Just looking at the nails.
Steven Sashen
Yeah. So, okay, so again, let’s just start there. So we have four prints on the upper left. Let’s say if you’re. If you’re thinking about this, like looking at a clock, the ones with the hand that is pointing towards 10 o’, clock, they are the. The. The nails are pointing, like towards one o’, clock, so it’s walking kind of diagonally up. Am I seeing this correctly? Tell me if I.
Jae Gruenke
Yes. Yeah, yeah, yeah.
Steven Sashen
And then you can see the two. The two prints, especially the one on the right. There’s. What if you’ve had a dog? You know, there’s the kind of heel part and then there’s four toes and, you know, toes. And then on the lower part of this picture, which is called, let’s call it, you know, pointing at five o’, clock, there’s something that looks similar, but interestingly heading kind of like directly horizontal. So they look like dog prints, but they’re heading in a different direction. And there’s one that’s much bigger than another.
Jae Gruenke
Yeah.
Steven Sashen
Okay.
Jae Gruenke
And. Yeah, and they’re. They’re different animals headed different directions.
Steven Sashen
Yeah.
Jae Gruenke
And is the prominence of the nails on, like, you could still see them. Richard always used to say there are so many different kinds of dogs. And, like, everybody has that experience where they get super excited because they’re sure it’s a mountain lion, but it was actually just somebody’s big dog. But one of the tells for a dog is that their nails are often just hanging out just for regular walking, which a wild animal won’t do. He calls it sloppy feet. That may also be relevant to questions of barefoot. Barefoot function for humans is like. Well, if you’re mostly indoors.
Steven Sashen
Wait, I got. I got to tell you something funny. Somebody is trying to. Developing. Developed a new way of manufacturing toe socks and he sent me a pair to try. Now they don’t work for me just because I have Morton’s toe. So my first toe is shorter than my second toe, which is the technical, the accurate way of saying it. Most people just say second toe is longer, but it’s first toe is too short. And the, the angle from my second toe down to my pinky toe is, it’s not crazy severe, but it’s enough that with these socks it’s too tight and squishy, pulling my, my second toe back and too loose on my first, fourth and fifth. But that’s not the point. The point is when he sells the socks, he sells them with a toenail clipper, which is awesome.
Jae Gruenke
Yeah. It’ll really, really tell you where you’re at. Yeah. Where your feet should be.
Steven Sashen
Okay.
Jae Gruenke
Yeah. So anyway, so these were prints that were clearly made when the, they’re in dirt. They’re clearly made when the ground was wet and now the ground has dried and they’re, they’re keep bumping on Mike. They’re, they’re, they’re deep and they’re crisp and you know.
Steven Sashen
Yeah.
Jae Gruenke
That like if you, you, so you saw one pair of prints like this when you’re out tracking for a whole day, like that would be like an amazing gift from Santa Claus. So, so anyway, the, the, the prints, we’re going to look at the prints on the left because there’s more disruption in them. But so, so the pressure release again can happen within the print or around the edges of the print. It depends on many factors. Like the most fundamental one and the, and thus the most valuable to a tracker is what was the animal paying attention to, thinking, doing, about, to do, just finished doing. Because all of that’s reflected in the direction of pressure. And then obviously it depends very much on the ground. Like again, was it mud or was it hard dirt? Was it. Well, if it’s rocks, you probably, you’re not going to even really see a print unless you’re top brown. But so how much the ground yields in response to how much pressure from how the animal is moving. So at lower amounts of pressure are reflected within different kinds of movement of the ground within the print. Okay, so you can see that there’s like. Can you see my cursor? Yeah. Okay, so you can see that there’s loose dirt towards the back of the pads print. And you know, and if there’s anyone out there who’s good at animal tracking who wants to email me and tell me all the Stuff I’ve gotten wrong, that would make my day. So please do. But. But where my skill level is at. Yeah. So you could see. So all of that looseness, that’s probably not just schmutz that got blown in after the print dried. Right? That is. That’s breakage or shifting in the ground as the animal’s weight passed across the paw.
Steven Sashen
Okay, so let’s pause there. So when you talk about pressure release, then obviously it sounds to me, and please correct me, that we’re talking about one or two things. One is just the release part. That as the pressure is being released, basically past mid stance is one way of thinking of it. Past the point where you have the most pressure into the ground. But the other is that the amount of pressure into the ground at all, which is kind of that, you know, just when you’re getting to mid stance, that’s impacting things also. And now I can’t tell, you know, where the light is, but it also looks like in addition to the loose stuff, that there’s. That there’s an angle to it. So the depth of the print is different on the. Let’s say, you know, the easiest way of saying it, the left side versus the right side. So are all these things factors for when we use the terms pressure release or even just pressure?
Jae Gruenke
Yeah, I mean, so this is where, like, I’m at the limits of my knowledge and practice. I don’t believe so. The. The side of the prints at the top of the screen, like, there are high ridges.
Steven Sashen
Right.
Jae Gruenke
As though. As though the animal. So maybe that’s the downhill side. And in on a muddy ground, the animal’s paws slipped slightly to the left as it was walking. And so that makes the little ridge there. Or maybe the animal was coming in and actually turning.
Steven Sashen
Turning to the right.
Jae Gruenke
To the right. Right, exactly. So that puts more force to the outside. I don’t think those high ridges count as pressure releases, but I’m not sure.
Steven Sashen
Okay.
Jae Gruenke
And. And no one ever actually properly defined pressure release. For me, there’s just. The term is used and the types are explained. And my definition that I derive from that is the way that the ground releases the pressure created by the animal’s paw.
Steven Sashen
Okay.
Jae Gruenke
By the. And the animals. Pause the interface, but by the animal’s movement is what we’re really talking about here. Right? Yeah.
Steven Sashen
Okay.
Jae Gruenke
And so, interestingly, like, at lower speeds, lower force, a lot of the pressure releases that you’re looking at or that also tell you how fast the animal was moving. I mean, you would look at Gait patterns. So obviously the prints would be in a different series of prints would be in a different arrangement if they’re. They’ve changed from walking to trotting or whatever.
Steven Sashen
Right.
Jae Gruenke
Actually, apparently a coyote has 33 different gates.
Steven Sashen
Wow. Cool.
Jae Gruenke
Yeah. Add two legs and goes crazy. So. But, but also, again, like, depends on the substrate, the ground and. But the way that the ground breaks is also reflective of the animal’s speed. So is it the little bits of schmutz. It’s not a technical term. Or is it. There are. There are disc breaks where. Where like actually just a little chunk of ground could slide a little bit backwards. And these all tend to show in the forefoot. Sorry, no, that’s not the right term when we’re talking. Talking about animals. Pads of the foot, the front, before, in front of the arch. Right?
Steven Sashen
Yep.
Jae Gruenke
Okay. And those are all lower speed. So this little bit of. Again, schmutz, probably the ground didn’t move or break that much because it was so wet. I mean, I don’t know.
I’m already exceeding what I can tell from this. But when the speed and force go up, then you start seeing this breakage out the back. Right, right. So off the. Well, it’s not. It would be the heel if it were a human print, but that’s not.
Steven Sashen
Well, no, it’s a thing. It’s a thing that. Before you even said it, what I found myself thinking about, and people have experienced this. Let’s just use flip flops as a bad example, is that typically, you know, when you’re walking, certainly in a particular way in flip flops, you’re kicking stuff up behind you that then can land in what you stepped, the hole that you stepped, that you created when you stepped or lands in the sandal, or if you’re. When you’re. I’m thinking about running at full speed. So when a sprinter is running at full speed, about 90% of the force is straight vertical. It’s like you’re hopping up and down. When you’re at maximum velocity, all you have to do is keep hopping up and down and you’ll stay at max velocity for a while. You just can’t hop that long for. For a highly trained sprinter, 15 to 20 meters and. But there’s some horizontal stuff as well. And anything that’s any sort of horizontal force that’s moving you forward has to be pushing something back.
Jae Gruenke
Right.
Steven Sashen
Okay. Simple enough. All right.
Jae Gruenke
Yes, exactly.
Steven Sashen
Okay, cool.
Jae Gruenke
So all of this is cool stuff when looking at animal prints.
Steven Sashen
Yes.
Jae Gruenke
But what about Humans on pavement. Interesting, because unless you’re Godzilla, there’s no pressure release in the ground. Or unless there’s a little bit of, like, grit or whatever on top of the pavement that could slip.
Steven Sashen
Yeah.
Jae Gruenke
The ground is not going to give.
Steven Sashen
Right.
Jae Gruenke
So where. So what does.
Steven Sashen
That’s an interesting question.
Jae Gruenke
Yeah. So I’ve been thinking about this for, like, five years, since I learned about releases.
Steven Sashen
Well, actually, it’s an interesting question that might be moot because I don’t know that anything has to. So what we’re talking. Wait, this is. God, this is really interesting.
Jae Gruenke
So I’ve got an answer for you, but I’m loving what you think about.
Steven Sashen
Do you want me to try. Do you want me to try and hack it out before you. Before.
Jae Gruenke
Yeah, hack it out. That’s great.
Steven Sashen
Okay, so imagine, just for the fun of it, I’m going to be really extreme about this. Imagine that with every step you take. And I’m going to think about walking. You know, Wait, I’m going to think about when I was. When I was 10 years old or 9 years old, and I was. I went to a day camp down the street from where I grew up, and. And there was one kid that was faster than me, made me crazy, and he did something, or maybe someone told me that he was doing something where he was basically, like, flicking his foot on the ground. Like, he was literally doing this thing of, like, flicking his foot, you know, to behind him, to move forward. And I tried that for a while. I just didn’t feel right. And I stopped doing it. Or it’s similar to what people think of as toe off. That when your foot is coming off the ground and it’s just your toes, you should, like, literally, like, flick your toes back. So if you were in something that was like sand or something soft, you would be flicking a thing back. When we have pavement, there’s nothing to flick back. And I’m not suggesting that’s the right way to walk. I’m using this extreme example to hack it out in my brain. This is really fun, by the way. Thanks. So. So there’s nothing that there’s no evidence that you’re flicking back on the ground. The only place where you might be able to notice that is, let’s say that you replaced. And we’re going to do this with one stride, because I’m going to use a crazy example that you replace the insole of your shoe or a big chunk of the sole of your shoe with something like Styrofoam. Like, you know, if anyone’s gotten an orthotic made and they step in that really compressive foam, you would see something that looked like these prints in the insole or sole made with that compressive foam. So the force is going somewhere. Assuming that you’re applying this horizontal force, the force is going somewhere, and the question is. And it’s going to have to be at some, you know, downward backward angle, otherwise you’d be going in the opposite direction.
Jae Gruenke
Right. I mean, unless you turn a corner or something.
Steven Sashen
Yeah, yeah, well, but basically downward backward with, you know, some, some angle off, you know, off of 180 degrees.
Jae Gruenke
So.
Steven Sashen
So on the one hand, where I’m going with that is, okay, if you had something that was absorbing that force, then you’d see something. You’d see that effect in that, you know, in that outsole. You’d be seeing the pressure. You’d see the pressure release to fight. Despite the fact that we don’t have a very specific definition that we’re working with.
Jae Gruenke
Right.
Steven Sashen
If you don’t have that, then the magic question is, so this is Newton’s, Newton’s law. Every force, you know, equal and opposite direction don’t have to go into the details. So what would be happening is that force would be going back into your toes if there’s nowhere for it to be expressed by compressing something underneath it while there’s still those forces are matching. But if you, if you have an immovable force that you’re pushing against, you’re going to feel more, you’ll feel that more in your toes, for lack of a better term. And it’s going to be more than just your toes. Of course. Let’s not get too picky. We’re just trying to hack it out. So that could be putting additional strain on the musculature when you’re doing this kind of flicky motion. Now, my argument, the question would be, is it more than we can handle and is that better? Because that way, that immovable force matching with your foot is what’s actually propelling you forward better.
Jae Gruenke
Right.
Steven Sashen
So these are the things I haven’t landed anywhere yet, but this is just how I’m going through it. To think about what you would do with this information and how that relates to the question of, you know, hey, I think I need something, quote, more comfortable.
Jae Gruenke
Right? Yeah.
Steven Sashen
How’d I do?
Jae Gruenke
You are, you have landed within the field of possibility for this. And it, like, so it’s not, it’s not, you know, like an animal tracking. It’s like, well, what’s the animal doing? How was the speed? And then what’s the substrate?
Steven Sashen
Yeah.
Jae Gruenke
Right. And then you’re going to get a diff from the exact same animal movement, although it probably wouldn’t be the exact same because every movement is created in rapport with the ground and the amount of force used. But you’ll see a different level or there’ll be of pressure release depending on how much the ground can move. Right.
Steven Sashen
You can, you can do this with my, with the shoes that I, I train and sprint in. So I train and sprint in our, in our speed force shoes. And it’s what I’m wearing right now. And what’s very interesting is I said I’m testing two different insoles, the one I’ve been wearing and this new one. And the first thing I felt when I put in the new one is that I don’t have the little divot underneath my big toe that I have created in the shoe that I’ve been wearing for a little while.
Jae Gruenke
Right.
Steven Sashen
I feel it dramatically. It feels very wrong.
Jae Gruenke
Yes. Although again, I wouldn’t say that that little divot is ne. Well, is necessary, but. Okay, it might be. So let me.
Steven Sashen
Well, I’m just saying that, that what I have in my, in my left foot is a material that does, that does compress a bit over time. And what I have in my right foot is a material that hasn’t compressed and very. And compresses very, very, very little over time.
Jae Gruenke
Right.
Steven Sashen
So I’m just feeling that difference.
Jae Gruenke
Yeah, yeah. And so I want to make a distinction here between, between compression.
Steven Sashen
Right.
Jae Gruenke
Pressure release.
Steven Sashen
Right, okay, please.
Jae Gruenke
Because, so, and in, in running or in biomechanics, we talk about this as different ground reaction forces.
Steven Sashen
Right.
Jae Gruenke
So in with running, we tend to think a lot about vertical ground reaction force. And these are components of a single force. This is also like, I think to, to you have to be picturing like graphs to talk about the vertical versus horizontal ground reaction force, basically. But it’s not that they’re separate forces, honestly, it’s one force in a particular direction. And. Yeah, it just describes how much up and down that force over time.
Steven Sashen
Over time. Yeah, it’s a. You have, you have a. So you’re walking across a force plate and as you’re walking, the amount of force and the direction of that force is changing because of course you are moving across something or one way of thinking of it is an upside down pendulum. So for the sake of saying it, so the string of the pendulum is attached to the ground. And as the pendulum Swings across in an arc from like, you know, one 1 o’ clock to 10 o’.
Jae Gruenke
Clock.
Steven Sashen
The amount of vertical and horizontal force is changing.
Jae Gruenke
And that’s basically that, that becomes very relevant to the like how much cushioning do you really need part of this conversation? Okay, so, yeah, so, right, so, but so the horizontal ground reaction force there is divided into two directions. Again, when we talk about gait antero posterior horizontal ground reaction force. That is front to back, front and back. You know, so, and so you would think about that also, you know, if you’re thinking about pushing back or making that flicking movement that you talked about, you know, that’s that direction is interior, posterior. It’s actually posterior. You know, it’s the backwards pushing, not the upwards pushing of getting into. So there’s also medial lateral, the sideways ground reaction force which again, if you were running around the curve in a track or going around a corner or whatever, you’re going to push a little more to the outside. You know, you’re going to have side. But also because in running there’s always medial lateral ground reaction force because the center of mass is always shifting from foot to foot. Maybe.
Steven Sashen
Yeah, because your, but because your feet are basically hip width apart. So you’re always going kind of back and forth, you know, left and right a little bit. And by the way, optimally. Yeah, well, a little bit, yes. Quick assignment.
Jae Gruenke
Not always.
Steven Sashen
There’s someone, someone who will remain nameless who talks about how, you know, there is this, this left to right kind of pendulum motion as well. And, and that you need to work with that. And I pointed out that with sprinters they have a good amount of that in large part because their thighs from like mid thigh up, you know, basically middle of the hamstring up have gotten so big that they can’t get their legs any closer. Yeah, I’ve hung out with these guys. They can’t fit in pants. So, you know, their feet are not hip width apart. So they’re bouncing back and forth left and right quite a bit. Just because their legs would can’t. They have to get around each other.
Jae Gruenke
Right. And that, that, that again is probably not a bug, but a feature. It’s like, you know, if, if being it being okay. So everything can go to too great an extreme, but it’s being very fit and strong. Not necessarily, you know, a bodybuilder or something messed with one of your fundamental gates of your species. Then I don’t know, you were invented, not evolved is.
Steven Sashen
Yes. Okay, so medial lateral.
Jae Gruenke
Right, right. So anyway, so when we think about cushioning. So now I’ve, I’ve stopped the, the share self view. That’s what I want. Yeah, I’ve stopped the sharing because now we’re shifting to the physical. I’ve got a sponge here.
Steven Sashen
Okay. Okay.
Jae Gruenke
So if the ground can’t give, when you push front to back, side to side combo, then then yes, it pushes you forward more. But there is something, you know, if you can move backwards at all, if anything can slide backwards, if anything can give, it also will. Right?
Steven Sashen
Yeah.
Jae Gruenke
And feet are not these just unitary things. So let’s say that something is going to shift. If it can’t be the ground, it’s going to be your foot or it’s going to be something between your foot and the ground. Right.
Steven Sashen
So for example, some Xero shoes customers experienced that with a couple of our products for a little while as they were walking. The sock liner, the insole was shifting backwards because it was not made correctly. We’ve replaced them and if you’re having that experience, contact us. But we’ve replaced them with the thing that’s made correctly. But it literally with, you know, every step, tiny little bit, it was just shifting back and back and back because the insole was giving. So the thing between your foot and the solid part of the shoe was giving.
Jae Gruenke
Exactly. And like famous example or you know, I don’t know, it’s probably already too far in the past for people, but when Ellie Kipchoge’s insoles both went.
Steven Sashen
Oh, I didn’t know that.
Jae Gruenke
Sideways out. Oh yeah. This was like Berlin Marathon 2016.
Steven Sashen
Which is, which is when he ran a 201.
Jae Gruenke
Yeah, that was a. And it was early super shoes that. Yeah, nobody heard the word yet. Yeah, it was all very hush hush, but it was, it was a new model and somehow they screwed up. Interesting. Both. I wrote a whole blog post about it. How both of the sock liners went out of his heels to the right. So coming across the finish line, you remember he’d like like the heels of his, they were literally flapping out the right side, flapping around his ankle, out the right side of his shoes. That’s the greatness of the man. Like whatever phased him, he handled it so that it had no effect and he had an amazing race.
Steven Sashen
Well, it says something else, actually. It says something else about the mythology of footwear componentry and. But that’s, that’s a whole. That’s a rabbit hole. We’re not going to go down.
Jae Gruenke
Okay, well, I’m super curious. But later. Well, next Time we have hot chocolate.
Steven Sashen
Well, the simple thing is, what is it about a shoe that’s actually making it better? And there’s a whole lot of complete hand waving about it. And. And of course, if you. There are examples of people who’ve come up with things that don’t inherently make someone better, but it just so happened that the person wearing that technology beat other people. And then suddenly, either that technology becomes ubiquitous, everyone’s using it, or it gets banned by the US Olympic Committee because it’s patented and the bigger companies can’t use it, so they have to make it go away.
Jae Gruenke
Right, yeah. The funny. When that. When it’s. The bigger. Anyway, yes, yes. Well, as I’ve reflected upon throughout my long career, humans are obsessed with cause and effect and terrible at correctly identifying it.
Steven Sashen
And the only thing we’re worse at than correctly identifying it is remembering how bad we are at correctly identifying.
Jae Gruenke
Get it right once and you think you’re. Yeah, you’re always right.
Steven Sashen
Okay, back to the sponge.
Jae Gruenke
The sponge. So hopefully it’s not getting my hands too wet. But. So this is our. This is something that can yield. Right. And so again, when we think about cushioning, we think about something solid on
Steven Sashen
the bottom, something pushing down the top.
Jae Gruenke
We think about it doing this for you. Holding the sponge in one hand and dropping my hand on the other. Or it could be the other way around. Amounts to the same thing. Right? That’s. That’s the cushion of your running shoe, potentially.
Steven Sashen
So just to be clear. Yes. I mean, for people who aren’t seeing it, Jay was holding one hand parallel to the ground, palm up, putting a sponge on it and then slapping it. Either slapping her other hand on top of it or slapping the hand with a sponge to the hand that’s above it. So. But suffice it to say, point is, what people are thinking about too, is that vertical impact, like running, is hard on your knees, and therefore we have to reduce the vertical impact forces. That’s basically the way people. People think about it very casually.
Jae Gruenke
Okay, wrong, wrong, wrong, wrong, wrong. But, yes, exactly. The pounding, Right.
Steven Sashen
Yes.
Jae Gruenke
So. And people pound. You don’t need to pound. That’s all learnable.
Steven Sashen
Yes, Totally optional, but let’s.
Jae Gruenke
But. But the whole point here is we’re not talking about the pounding, Right. Because for me, this conversation started when I was like, hm. And maybe it’s not a trend, maybe it’s just me, but. And who. I heard. But why would somebody who’d been in truly minimalist footwear for, like, you know, five, eight, 10 years. Go back to cushioning. Personally, I put cushioning on, and I’m like, I don’t like this very much. Right. So. Right. And so they have already, I’m. I guarantee you, modulated their gait so they’re not pounding.
Steven Sashen
Right.
Jae Gruenke
That’s like one of the very early corrections that happens when people change their footwear. Yes. Yeah.
Steven Sashen
Okay. So I’m gonna. I’m gonna say. All right, that’s an assumption. Maybe. Maybe they. I assumedly they have.
Jae Gruenke
Right.
Steven Sashen
But the other. The other thing I’ll throw in there is what I have seen in the lab is that other than very highly skilled runners, and I’ve only seen this with runners, every different thing you put on your feet changes your gait, even if you are. I’ve seen accomplished barefoot runners put on this. I’m going to describe it literally what I saw, so I’m not being metaphorical or hyperbolic or whatever. Very accomplished barefoot runner. We’re watching his gait by filming him from the back and from the side at 500 frames a second. This is in the lab with Dr. Bill Sands when he was out here in Colorado and then put on a pair of five fingers and instantly started over striding and heel striking.
Jae Gruenke
And I know, it’s so funny. The five fingers, they really do that. And I think it’s.
Steven Sashen
Yeah. But it was also the same with any other shoe and didn’t know that he was doing it. And conversely, we saw people who had never worn a minimalist shoe before, but they were very accomplished runners. Oh, sorry. They were medium accomplished runners. And when they put on it was because we were doing this test with one of our sandals. They would. Their gate would immediately change. And again, they didn’t know it. Did it become perfect? No. But did it change dramatically from when they were wearing a thin, you know, a running flat? Definitely. The very, very accomplished runners, nationally ranked and above, you could put bricks on their feet or feathers on their feet, and nothing changed. It was just that movement pattern was so ingrained that it didn’t change. And it’s like it reminded me of seeing Ben Johnson when he. And Ben’s a couple years older than I am seeing him when he was like 50 something and some reporter wanted to see how he was doing and took him to the track and like, let’s race. And Ben’s start looked like any Olympian you would see at the age of 20. It was so wired into his body that even though he weighed like a good £220, it looked like one of the best sprinters you’ve ever seen in the world. Because he was one of the best sprinters ever in the world.
Jae Gruenke
Right.
Steven Sashen
Nothing changed.
Jae Gruenke
Right.
Steven Sashen
And look, I’m going to pat myself on the back some. I showed a video of me at 63 doing a standing backflip to a 33 year old Olympian. And, and he was very upset with me and I said, I’m an inspiration, get over it. But, but the joke is if you look at a video of me doing that same backflip when I was in my 20s or 30s, it’s fundamentally identical, except just not as high. That’s it. So I’ve done, I have, I mean, up until my, my, when I turned 40 or so, or maybe 45, I had done literally 20 or 30,000 of them. And in fact it’s so in my body that when I do it now, and I don’t know why this happens, I literally from the moment, like a split second after I leave the ground, I black out, like completely black out until I see my feet about to hit the ground. And yet I still make it every time. I don’t do them all the time because it terrifies me.
Jae Gruenke
Right.
Steven Sashen
But nonetheless, it’s just, it’s wired. Okay, so that’s it.
Jae Gruenke
So all of that. But. And you can have a stompy way of running and just because you’re in like I, I worked with the British Olympic, like, I think it’s a particularly British thing though. I’ve seen American runners do it too. Elite runners.
Steven Sashen
Yeah.
Jae Gruenke
Run in what I, what in my notes will say stompy. But actually what it is, is, and you’ll see it from the first step that they’re creating movement by creating ground reaction pours first. So instead of leaning forward, they’ll hold their weight back, lift the leg up in front and accelerate it towards the ground. Right, right. And so this, this requires that your weight be in the wrong place. But it’s a common G. And like once you get underway, it doesn’t show as much. I can still see it, but it’s a common gate pattern. So yeah, so it’s, it’s, it’s not like impact, but, but okay. Nonetheless, what I want is like this other function of cushioning which isn’t about vertical, the vertical ground reaction force. Because another thing that it can do. And let me see if I can arrange my hands and self so that you can really see this is when say here’s your mid stance.
Steven Sashen
Okay. So I’m going to break this apart as you’re doing it. Keep your hand in so mid stance. Basically you’re just for all practical purposes, compressing the sponge straight down.
Jae Gruenke
Yep, yep. Sponge is. I’ve made a hand and sponge sandwich. Okay, so the top hand is the foot, right?
Steven Sashen
Yeah.
Jae Gruenke
Or the, or the. Well, the weight. Right. Because we’re talking about a variety of possible scenarios here. But anyway, and then going to push forward. You see, the bubbles in the sponge are deforming as the top of the sponge moves backwards. Because I’m dry, I’m pulling my hand backwards. So it’s the sponge.
Steven Sashen
Right.
Jae Gruenke
That’s allowing, that’s allowing the pressure release. Right. The pressure of my hand pulling backward. That would be posterior horizontal ground reaction force. And you see, the whole thing is shearing.
Steven Sashen
Right. I was going to say you’re getting some shearing forces. But my question, the question that comes up. So, yes, if you have, if you have your hands again, parallel to the ground like and then a sponge in between, and if, if one hand, while still connected to the sponge, the top hand is pulling back a little, you get shearing forces. Now the question, of course is are people creating shearing forces and are. And is that necessary and, or appropriate or just what they happen to be doing?
Jae Gruenke
Right. All of the above.
Steven Sashen
Okay.
Jae Gruenke
Can be the case. Right.
Steven Sashen
Yes. And it’s also possible that you’re not. That, you know, you’re hitting the ground in such a way. I mean, if anything, look, we love to say you want to get your foot under your center of mass when you land. That’s a course completely impossible. There’s always a little bit where your foot’s slightly in front of you, so you get a little bit of shearing force forward when you’re at ground contact and a little bit backward because again, there’s got horizontal force. Has to create something backward in theory, you know, and, and there’s going to be a. If you’re accelerating in particular, there’s more shearing force on the way back than forward. Otherwise you’d be just going back and forth, back and forth, not going anywhere. So there’s going to be, there’s going to be some shearing forces. Right, okay, so we got that. And we don’t need to, you know, go into what percentage and how much and blah, blah, blah.
Jae Gruenke
Right.
Steven Sashen
We know there’s some. Okay, yes. Part of our investigation into cushioning and why people might like it.
Jae Gruenke
Yes. Okay, so there’s going to be shearing force.
Steven Sashen
Yep.
Jae Gruenke
It’s going to be. Is going to vary depending on, say, how fast you’re moving. But Also and significantly, in my experience, based on how you’re moving, how is the rest of you moving over that foot and when is the posterior? So we’re just going to address running or walking in a straightforward. We’re not going to talk about curves and where, when in the process of your body moving, like past your foot, is that happening? Right. And then what, what, where can the pressure release what can shear, Right. So if you’re on a, a cinder track, you know, like little bits of grit and gravel, like you can have some backward slippage. You’ve heard people do that, maybe you’ve heard yourself do that. Of the backward sliding gravel, walking in dry sand, deep dry sand, of course, you get the biggest backward, like the, it, it takes almost no pressure for that sand to slide backwards. And so you have trouble moving forwards. Actually, it’s kind of exhausting. If you’re barefoot on pavement and you’re creating a lot of posterior ground reaction force, either because you’re accelerating or because you’re moving badly.
Steven Sashen
Right.
Jae Gruenke
The ground can’t give.
Steven Sashen
So your skin is doing its thing.
Jae Gruenke
And it’s not just your skin. If you look at the cross section of a.
Steven Sashen
Well, I don’t mean the skin is a separate thing. I mean that’s just the interface.
Jae Gruenke
But yeah, yeah. So I like, so I’m not a tissue person, right? Like a massage therapist, a manual therapist. I even a physical therapist. Like they’re tissue people. I’m an, as you said, I’m a nervous system person. I’m a, I’m a, I’m a motor learning person. Fundamental actions of the skeleton, but also what our understanding of tissue is rapidly developing.
Steven Sashen
Let me see, let me see if this is useful. When someone says to me they’ve gotten them, especially if they’re running barefoot and they say, hey, I’ve got, I’m gutting a blister. Blisters. I say show me where. Oh, actually I don’t even say show me where. I can say if it’s on the ball of your foot, you’re over striding and then pointing your toes to hit the ground, you’re decelerating and that’s where the contact is. Assuming they’re not getting, not, you know, crazy and landing on their heel. If you’re doing, if it’s on your toes, you’re doing that kind of kickback thing, that toe off thing, right? So I use. Or a pivot or pivot, right. So either one of those is excessive horizontal force. And it’s, it is again, for lack of a Better description, your skin. That’s bearing the bliss of it.
Jae Gruenke
Yes, exactly. I hadn’t. I hadn’t thought about blisters, but that’s exactly right. Yeah. Blisters are another symptom of excessive horizontal ground reaction force that can’t be absorbed because of the whole constellation of conditions in that moment can’t be absorbed anywhere else except between. What is that? Your. Your epidermis and your dermis. Right, Correct. So if you look at the cross section of a. Of a foot, like a cadaver, you see that there is a tremendous amount of tissue between the sole of the foot and any bones at all.
Steven Sashen
Right.
Jae Gruenke
And so again, I’m not a tissue person. And also we are understanding more and more. People are often amazed to learn that everything about anatomy is not known. Right. Like, surely, like, we should know everything. You just look and you see what’s there. Right. Well, looking and seeing what’s there is not as straightforward as that. And we’ve been going through this amazing phase of people looking at the stuff that was considered artifact or just cut away to get it. What we thought we were really interested in. In cadaver dissection.
Steven Sashen
Yes, specifically. Yeah, Specifically things like fascia and quote. The interstitium.
Jae Gruenke
Yes. And I think probably the interstitium is.
Steven Sashen
That’s. That’s the new.
Jae Gruenke
Really relevant here.
Steven Sashen
Yeah.
Jae Gruenke
Be. So the fascia’s fascia. In the terms of Gil Headley, if people want to learn more about the interstitium, like, there’s an anatomist, Gil Headley, who does dissections. You have to know that a lot of his videos have, like, footage of cadaver dissections. You have to be.
Steven Sashen
For that fascinating and. And to be. And for the fun of it, discovered or not discovered. Identified by accident. Yeah, completely by accident.
Jae Gruenke
Yeah. But. But also because he was like, huh, what’s this? As opposed to, hey, that’s.
Steven Sashen
Get rid of this. Yeah, yeah.
Jae Gruenke
Right, yeah. And so the interstitium is like, it’s considered now a new organ system, and it was discovered only in that. To that degree in a few years ago in Western science. Although I’ve also heard the acupuncture. So, like, hey, that’s the triple burner. Like, we’ve known about that for millennia.
Steven Sashen
Yeah. I mean, the people who are studying this, including Chinese medicine people, say it’s not a direct match, but it might explain certain things. And for. For. Without diving into this too deeply, it seems that the interstitium is basically. Think of it, think of it just like fluid pathway across the entire body.
Jae Gruenke
Yep.
Steven Sashen
I mean, it’s.
Jae Gruenke
Yeah, yeah. And one of its manifestations is as a slippery membrane.
Steven Sashen
Right.
Jae Gruenke
Between everything, basically everything in your body and every other thing in your body. Every layer, every vessel.
Steven Sashen
Yeah.
Jae Gruenke
Everything, you know, and, and then these layers are not distinct from each other.
Steven Sashen
Right.
Jae Gruenke
They all merge into each other. Right. But the interstitium apparently has the fluid volume that’s four times what your cardiovascular system has, which is mind blowing. Right. And which also says like another facet here is like, if your feet are hurting, you may need drinking more water may help. Because when that becomes. Because the interstitium as, as a membrane between things and other things allows for shearing. It allows for anything to slide relative to anything else. So it’s probably really relevant here. But like, again, I’m, I’m out of my field in talking about that stuff.
Steven Sashen
So, so now, so now we’ve got, we know that there are shearing forces. This is assuming that your foot just isn’t sliding back and forth in the shoe or on the way.
Jae Gruenke
Right. In which case there’s going to be drag on the skin and you’re going to get blisters. Yeah. Right.
Steven Sashen
So, okay, so where’s, so where are we now in the question of how this might apply to people who eventually go, or for whatever reason think, you know, hey, I need something other than a minimal issue.
Jae Gruenke
Yeah. They’re like, I walk on pavement for a number of miles and my feet get sore.
Steven Sashen
Are you, are you saying that for you or are you saying that. No, no, that’s an example.
Jae Gruenke
No, that doesn’t happen.
Steven Sashen
I was just checking because FYI, it’s my favorite thing when someone says, but I walk on pavement. I said, I did 20 miles a day and York without a good chunk of a. Barefoot. Barefoot problem. So.
Jae Gruenke
Right. Yeah. No, that, that was like me quoting this hypothetical person.
Steven Sashen
Got it.
Jae Gruenke
Who feels like, you know, pavement is really hard on your feet if you don’t have some cushioning. Well, what function is the cushioning providing then?
Steven Sashen
Well, let me, let me, let me interject on that one because people have a misunderstanding about cushioning. And I’m just going to do the shortest version of this and if anyone listening disagrees, that’s cool. You’re wrong. So, so, so the research is very clear that cushioning doesn’t protect you from impact forces.
Jae Gruenke
Right.
Steven Sashen
What cushioning is doing is it’s, and the way I describe it is the difference between pressure and force. And so, and the, the example that I give is, if you haven’t seen it, there’s A slow motion movie. Now you can watch it on YouTube from way back when of some big circus guy like 350 pound guy taking a cannonball to the stomach. And it’s in slow motion. And the pressure, the way the pressure is absorbed is that. And spread out. Is that when the cannonball hits him? Of course it makes him kind of double over a little and you see ripples of fat extending out from where the cannonball hits. Moving the pressure into a larger surface area makes it so that your feet don’t feel it as much or at all. But the force still sends this 300 and some odd pound guy flying into the tarp behind him. The force is still going up into your, through your joints or through your bones and ligaments and whatever, depending on how your, what your structure is. But mostly the issue is it’s going like through your bones into your joints which are not designed to protect that kind of pressure or that kind of force. Sorry. So, so what cushioning is doing more often than not is just making it so your feet don’t feel the actual amount of pain you’re inflicting upon yourself until the joints are so compromised that they finally give you a sign up.
Jae Gruenke
Right. But that’s the, that’s relevant again for impact, for pounding, for vertical ground reaction force.
Steven Sashen
Correct.
Jae Gruenke
Or mostly the, the mostly vertical component. Right. But so again we’re assuming that this is still a person you wouldn’t hear coming. Right. They are not pounding the ground.
Steven Sashen
Okay. Okay.
Jae Gruenke
But their feet end up sore. Why? Well, it’s. Maybe it’s that pavement is too hard and it’s on a natural surface. Okay. But first your nervous system is always regulating your movement gets back to animals and substrate relative to the characteristics, the qualities of the surface you’re moving across. So your nervous system should be handling that difference because rocks exist and people in it.
Steven Sashen
Look, we where we did evolve a lot of hard packed mud just as hard as concrete.
Jae Gruenke
Yeah. So,
Steven Sashen
but again we’re talking about the horizon.
Jae Gruenke
We’re excluding impact. We’re talking about a person who is creating by the way that they’re moving too much horizontal ground reaction force. They are pushing too hard against the ground. The ground can’t give if and they don’t have cushioning to give. So it’s within the tissues of the foot that that giving is happening. That’s my best understanding from what I’ve seen over 24 years of working with runners for that is a, is a very good way to get plantar fascia problems and solo the Foot pain.
Steven Sashen
So then if in fact, the foot is. The foot is doing the shearing or the tissue. The tissue underneath the bones of your foot are doing the shearing where you. Where you’re heading, or correct me if I’m wrong, it sounds like you’re heading to the idea that when they’re wearing something with cushioning, then they’re taking that out of the foot and putting it into the cushioning.
Jae Gruenke
Yes. Or at least to. At least enough.
Steven Sashen
To some extent.
Jae Gruenke
Right. To some extent, the cushioning is able to provide that pressure release.
Steven Sashen
So my only. I think it’s an interesting hypothesis where I’m butting up against it is knowing how this cushioning is made.
Jae Gruenke
Well. Right. And I’m sure the different types of cushioning. Different. Can do this to a different degree.
Steven Sashen
Exactly. Some, I mean, some just. There is no shearing at all. Some, there’s a tiny bit that. Again, like the little divot in the. The sock liner in my shoe is an expression of that. It’s not just the vert. I mean, because I’m not putting serious vertical forces from my big toe into the ground.
Jae Gruenke
Right.
Steven Sashen
Not happening.
Jae Gruenke
Right.
Steven Sashen
As I’m going from supination at landing to pronation and coming off that big toe when I’m running that big toe that it is. And it is a combination of vertical and horizontal force, but there’s more horizontal force. Even though I’m not kicking back at all or not this way. I’m not kicking back deliberately. There is some of that just because there is horizontal force.
Jae Gruenke
Right.
Steven Sashen
And because I’m. I mean, what I’m trying to do is actually make it as vertical as possible. And so I’m kind of popping off the ground instead of kicking the ground behind me. But there’s still a horizontal component to that. So clearly it’s being absorbed in small part by the insole in my shoe, which. Designed to be pretty. Not sheery.
Jae Gruenke
And the rubber surface of the track,
Steven Sashen
Most of the track, the indoor tracks, which is what I’m dealing with right now, they all suck. There’s no give on those things at all.
Jae Gruenke
Oh, okay.
Steven Sashen
Yeah, they’re horrible.
Jae Gruenke
So. Right. But like, this gets us back to substrate.
Steven Sashen
Yeah, yeah, yeah, yeah.
Jae Gruenke
So there’s. There’s the amount of force and then there’s all the. All the ways that it could be absorbed. Right. And so, so, so again, you’ve got a field of possibility here, but if the way that you’re organizing your movement and this is where it’s the rest of the body that matters, it’s not your feet because. Because the, the release of your weight, it should be a release like you, you mentioned reverse pendulum, and that’s like the simplest aspect of it. But actually, again, because we’ve got two feet and neither one’s in the middle. And although there are runners who run like they’re on a tightrope, they, they are doing a great job of like the main thing that causes post tib problems, by the way. But. So that digression lost my train of thought.
Steven Sashen
But anyway, I’ll give it back to you.
Jae Gruenke
It’s a spiraling action from foot to foot.
Steven Sashen
Yep.
Jae Gruenke
What I call the core action because we need an accurate way of talking about this. And core stability is an extremely confusing term. Sounds like still.
Steven Sashen
Right.
Jae Gruenke
And when in fact there’s specific motions that your trunk needs to do. Serge Grokovetsky coined the term spinal engine. That’s another good way of talking about it. Looking just at the spine component that drive and release your weight from foot to foot in walking and running. And when that’s operating the way it should be, you don’t create excessive horizontal ground reaction force in any direction.
Steven Sashen
Got it.
Jae Gruenke
And, but if you are. So you can be in very cushioned shoes, you can be in shoes with a lot of give. In fact, in response to that, you probably stiffen your body up more because. Right. And so then you actually increase your horizontal ground reaction force. You can get sore soles of your feet in hokas. You know, and that’s just because the, the, all of the, the factors here have aligned so that you’re creating a more horizontal ground reaction force than the sole of your foot. The cushioning of your shoe and the surface you’re moving on can absorb. So it’s exceeding what the sole of your foot can handle. And I’m sure there’s also a conditioning effect in the sole of the foot. Right. Those tissues can become stronger and more elastic. They can be better hydrated. Right. So there are many, many factors here. But I think if you just change the cushioning variable and you go from uncomfortable from sore soles of the feet to not soar, then it’s your, it’s your horizontal. It’s like you’re pushing too hard with the ground because your body is too stiff.
Steven Sashen
Your body’s in.
Jae Gruenke
Well, go for it.
Steven Sashen
I’d say either some combination of too stiff or just like in slightly the wrong place. So again, if we’re using the upside down pendulum with the string on the, on the ground swinging above, you’re just not. You Know, and I said before, like between 1 o’ clock and 10 o’ clock or 1 o’ clock and 11 o’ clock would be. If there’s something a little off between one minute after the hour. Excuse me, one minute after the hour and 50 and one minute before the hour, you could be a little off there. That could be showing up in this excessive horizontal force. It turns into something where the cushioning makes your feet feel a little better.
Jae Gruenke
Yes. And that is. Right. That is key. That is a key factor here. It’s like the spiraling action for foot. But if your weight has not gotten far enough past your foot when you, when you, for a variety of neuromuscular reasons, conclude that it’s important to start pushing at the ground or start trying to get your heel off the ground and get onto your forefoot, then your, your horizontal ground reaction force is going to be very, very high. And in fact, if you do exactly that too much and your ankle is stiff, that’s your, that’s your Morton’s neuroma. That, that’s your, that’s your metatarsalgia.
Steven Sashen
So there’s two things that I, that I’m loving about this. First of all, that was a really fun trip. So thank you. That was great fun. I hope other people found it interesting because having to think through this in real time was an absolute blast. And, and, and I’m going to say, and I’m being patting both of ourselves on the back about this one. When we talked about cause and effect, you know, what I see so often is people misrepresent the effect and then think that they understand the cause and then they try to impact the effect. That sounds too out there. Let me describe what I’m thinking of. Go to a high school track meet, listen to the parents of the sprinters yelling, get your knees up. No, your knee. Getting your knees up is not an act, an active thing you do. It’s an effect of hitting the ground correctly. So it, you know, trying to work on the effect where your knee lands is not going to have any value whatsoever. So, so. Oh, crap. I had two thoughts that went. And I think I lost one. Anyway, so we took a really cool trip. There are lots of ways that this could have gone off the rails other than our tangents of, of cause and effect, which we didn’t. So a, I’m going to pat myself on the back on this one, watching. And I could be wrong. You can tell me at some point my video about how to walk quote, naturally. The whole idea is that if all you did is lift your foot off one foot off the ground, and then push back a tiny bit with the other foot when it’s pretty flat on the ground, so you’re not getting excessive shearing forces really, and then just let your foot naturally hit the ground to keep you from falling on your face, lather, rinse and repeat that and you’re getting rid of a lot of horizontal force. I mean, tons of it. More, more interesting and relevant and fun for me is that the fundamental thing that we say about barefoot movement, natural movement, is if it hurts, you’re doing it wrong. That if it hurts, that’s a signal that there’s some way that your foot is trying to be a coach. And if you can listen, you can correct something that is way upstream, literally like higher up in your body that will, that’s just showing up in your foot. The simplest one is if you take off your shoes and you’re an over striding heel striker, landing on your heel is going to hurt like crap. And if you care to pay attention and experiment with the ways that we tell people about how to experiment, different cues, different tips, et cetera, then that’ll go away. But what might be left over for some people who’ve gone pretty far down the path and gotten pretty accomplished could be some little tiny thing where they’re still getting a message. And I will tell you, some of these very accomplished, seemingly accomplished barefoot runners, when there’s a little thing that suggests their form might be a little off, they do not take that well. Not. I mean, there’s some who do, but there are many. It’s like, well, I’ve run 10 marathons barefoot. I go, I know. And Right. And then they get really mad.
Jae Gruenke
But that’s like this, let’s have a growth mindset here. People like, nobody’s talking about JJ.
Steven Sashen
We’re talking about humans. We’re talking about humans.
Jae Gruenke
But as Moshe Feldenkrais said, there’s no limit to our ability to improve.
Steven Sashen
Correct.
Jae Gruenke
Correct. If you want a really satisfying life, that is your best approach. I want to. Actually there’s like a time. Although that would be a perfect place to end this. I do want to address one thing that you said about pain that I think is really important for people to understand.
Steven Sashen
Okay.
Jae Gruenke
Which is that you’re. If you listen to your feet, they’ll be your coach in the moment with something like a heel strike. But when you get into chronic discomfort.
Steven Sashen
Correct.
Jae Gruenke
Then you get the opposite thing happening. You get a compensation pattern which is always you doubling down on the thing you were doing that caused the problem.
Steven Sashen
Yeah.
Jae Gruenke
Because that is the best and safest and most familiar way you know how to move. And so you can get into this, this vicious cycle where things get worse and worse and you feel like hokas are the only answer. Right. And so there, that’s. And you are going to get them. Yeah. I mean, the more your feet hurt, the stiffer you’re going to be in walking and the worse it’s going to be. And so that’s where you need to come out of walking or running and have a movement learning experience that doesn’t involve pain at all. Probably not even on your feet that is going to change your movement. Inflammation can subside in a few days. You’ll forget you had the problem. So that’s, you know, like, so people need to understand just because your pain isn’t going away, like it’s a, it’s not that you failed in listening to your feet. It’s that you, the cycle can’t be broken unless you, unless you break it. Unless you step away and have a different kind of learning experience.
Steven Sashen
It’s a good, it’s a good kind of curiosity where, just to reiterate, because I think what you said is so important that that real time feedback, which is what engenders new movement patterns or can engender new movement patterns by trying. I mean, you know, it’s the story that I tell. The first time I. Second time I ran barefoot, where after the first time I ended up with a giant blister on the ball of my foot. The second time I’m thinking, how can I run where I’m not doing the thing that clearly caused the blister? And I had nine and a half minutes of pain because I’m doing the same thing that caused the blister. And then it changed and then all the pain went away, injuries went away, got faster, blah, blah, blah.
Jae Gruenke
Right.
Steven Sashen
So that was, that was some real time feedback. But if you get to the point where you’re doing something wrong, that’s subtle, it’s not going to show up real time. It’s going to show up after the fact, long, more long term and more chronically, you know, like a day or two later, it’s going to start and if you keep doing the same thing, it’s not going to go away. That’s a whole, that’s a different kind of signal that requires a different kind of intervention because clearly that. Not trying to, you know, blame the victim, if you will, on this, clearly, for whatever reason, you couldn’t feel the thing that caused the problem a day or two later in real time. Now it may be possible that you can, but you haven’t up until now.
Jae Gruenke
Right.
Steven Sashen
And to find someone who can help identify that, that’s critical. And holy crap, is that a sales pitch for you. But let’s go. So, so, and there are other people who, who see this from a different perspective that are landing in the same place and haven’t thought of it like this. So I love it. So that’s awesome. Again, the simplest thing we can say is A, the feedback, the uncomfortable feedback is telling us something needs to change. B, we’re really bad at cause and effect. Find someone who might be able to help you who’s a little bit better and not so willing to jump on the first answer that sounds good in one’s brain. Because that’s what your brain is designed to do is come up with an answer to make you have to not keep thinking about shit it. And by the way, read a book called On Being Certain about that which is basically. Oh, it’s great. Yeah, it’s basically that the feeling of knowing that you get is designed to just stop your brain from going left, right, left, right, left, right, left, right, left, right, trying to figure out what’s true. And then you get a feeling of knowing and then you land on an answer that you can justify with the feeling becomes a circle. But that doesn’t mean you’re right. It just means that your brain has stop doing the energy wasting thing of trying to figure it out by just landing somewhere.
Jae Gruenke
And then, well, we’ve got AI taking that work away from us now anyway. So like whatever that’s, that’s that level of exhaustion, we’re not going to have to bear it much.
Steven Sashen
Yeah, it’s, it’s never hallucinating.
Jae Gruenke
Okay, so this hasn’t stripped mind all the, all of the knowledge from all of us who’ve done the hard work for.
Steven Sashen
Well, you know, it’s so funny, the whole thing with AI is the only thing AI knows is, is what it learned from what we’ve already put out. Anything that’s creative people don’t know this. The way it comes up with quote creative things is by making the prediction model for what should come next stupider. So it’s like the prediction model is saying 99%. This is the word or phrase that should come next. Let’s make it more interesting by making it making up the numbers 80%. Give me something in the 80% probability range. And sometimes you get A good creative output of that. Because no one else thought to do that. Because why would you have done that thing? That’s so obviously not the way you should do it. That’s how AI seems to be creative anyway. That’s a whole other world. We don’t need to go.
Jae Gruenke
Yeah.
Steven Sashen
So once again, as always, it is a total pleasure. People might, I imagine, want to follow up with you about that. Especially those who’ve had a little nagging something who have. Who wear minimal shoes sometimes, but not always because. But they think that maybe there’s something wrong because they get very apologetic around me in airports and I tell them to stop doing that. How can people find you and what you’re doing?
Jae Gruenke
Yeah. So My website is balancedrunner.com and there’s. I have online courses and I coach virtually. I also see clients in person here in Salt Lake City where I live. So, you know, my job is to look at your whole body. What are you. What is it about how you’re moving your whole body that’s causing the problem where you feel it sole of your feet or somewhere else. And then create a learning experience for you that gets you out of these ever deepening cycles of compensation that is very hard to get yourself out of and find out what’s really possible for you.
Steven Sashen
Yes. And looping right back to the Feldenkrais thing. It’s one of the other things that Moshe Feldenkrais identified is often the thing where you have the pain. Pain is not the thing that’s causing the pain.
Jae Gruenke
So.
Steven Sashen
So that’s a thing. Anyway, again, pleasure. I hope you all listening slash watching enjoyed this. If you weren’t watching, check out the video because you’re gonna love it. If you’re not sure where to find the video, go to jointhemovementmovement.com and you will find links to all of those things. When you get there, you can opt in to hear about upcoming episodes. You can find all of the many, many previous episodes. You can find ways to support what we’re doing by spreading the word. Share like give us a thumbs up, hit the bell icon on YouTube. All those things. Again, you know how to do that. More importantly, maybe if you have any recommendations or suggestions about the show or any questions that you’d love to answer on the podcast or if you know someone who I should talk to, especially someone who thinks I have a case of cranial rectal reorientation syndrome around all of this, I’m game. Drop me an email ove m o v [email protected] and more importantly, until whatever is next for us and or you. I don’t know what that means, but it’s the way it came out of my face because I’m an LLM. Go out, have fun and live life feet first.