Enlightened Anatomy with Matthew Huy

8: Jules Mitchell on yoga butt, foot-on-knee and stretching science

• Matthew Huy • Episode 8

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Resources mentioned:

Buy Jules’ book: https://amzn.to/48Hmtd2
Jules’ website: https://www.julesmitchell.com/
Follow Jules on Instagram: https://www.instagram.com/julesyoga/
Join Matt’s email newsletter: https://www.matthewhuy.com/5-truth-bombs


Host Matthew Huy interviews Jules Mitchell, author of Yoga Biomechanics, who shares her background in yoga and biomechanics, discussing the integration of scientific principles into yoga practice. The conversation delves into the definition and application of biomechanics in yoga, the significance of tissue mechanics, and the influence of stretch tolerance on range of motion. They also explore the latest research on stretching, hypertrophy, and pain management, and discuss the implications for yoga teaching. Jules emphasizes the importance of research literacy and practical application for yoga teachers. Additionally, she provides insights into managing hamstring tendinopathy and the role of load in tissue recovery. The episode concludes with a discussion on the value of integrating scientific knowledge into yoga while maintaining the magic and experiential aspects of the practice.


00:00 Introduction to the Enlightened Anatomy Podcast

00:27 Meet Jules Mitchell: Journey into Biomechanics

05:27 The Importance of Biomechanics in Yoga

07:06 Understanding Forces and Tissue Mechanics

11:41 Debunking Myths: Foot Placement in Tree Pose

18:18 The Role of Science and Research Literacy in Yoga

28:26 Diving into Stretching Research

30:09 Pain and Stretch Tolerance

33:51 Exploring Hypertrophy

39:50 Understanding Hamstring Tendinopathy

48:24 Yoga Teacher's Role in Managing Tendinopathy

50:03 Closing Thoughts and Resources



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Saz:

Welcome to the Enlightened Anatomy Podcast, where we take a deep dive into the worlds of anatomy, physiology, and science to help you deepen your yoga practice. Now, here's your host, Matthew Huy.

Matt:

Hello and welcome to this episode of Enlightened Anatomy. today I am joined by Jules Mitchell, author of Yoga Biomechanics, which I'm holding up in my hands. A great read. Very dense, just like our book. so I think one that you pick up and drop off and Jules is an educator of yoga teachers and yoga practitioners, but I'll let her fill you in a bit more on her background. Welcome, Jules.

Jules:

Hi, thanks for having me. I love when people hold up my book or offer my book for me to sign because I can tell how much they've read of it by how worn it is. So there's a little tell there. Mine has pages falling out and people hand me this pristine book. I'm like, yeah, I know it's dense, isn't it? They get through maybe chapter one.

Matt:

Yeah, exactly. So, I'll let you do a little introduction of yourself A bit about your background and how you came into biomechanics.

Jules:

Yeah, that's a hard one because, it can be a long story and I'll try not to do that. But, um, my educational background primarily was in, believe it or not, women's studies and, my minor was in mathematics so it wasn't, related to any of this. And somewhere in undergrad, I discovered yoga. And so then yoga became my thing. Um, and then later in life, lots of circumstances, you know, how life happens. I somehow found myself in a graduate program in kinesiology cause yoga, kinesiology, exercise science, and they, funneled me into, biomechanics. I didn't really know what biomechanics was. I thought I was going to be studying more like anatomy type stuff. I just figured, hey, exercise yoga. Okay. And the reason why they'd funneled me into that was because, in that big span of time, I had gone back to school to study some engineering, because my father was an engineer. I thought that's what I wanted to do. And so I had all of the coursework for biomechanics. And in an exercise science program, that's uncommon. People usually have biology, but they don't usually have the mechanics side of things. They explained that to me and I still didn't understand what biomechanics was because I hadn't heard of it, and then all of a sudden I'm in the courses and my jaw is hanging open. I was like, oh, my God, they have graphs for this stuff. can actually see how tendons behave. this is unbelievable. Nobody else in the class was interested, but I was very interested. when I realized what it was, I was all in, and I was very thankful that I had advisors that saw who I was and what my background was and funneled me into the right place. So that's how I ended up teaching biomechanics to yoga teachers. I certainly wasn't the only one with those interests and questions.

Matt:

Great introduction. I like how you say about them funneling you in and how you found yourself at a master's it's almost like the path finds its way.

Jules:

that is exactly how I feel about it. to add to that kind of like, it's my dharma, I guess, not, not only was my father an engineer, so I had the background and the curiosity of mechanics design and physics but my mother was a professor at university. the teaching aspect is also, instilled in me. I grew up on university campuses, So the fact that now I teach physics, is, not a big surprise.

Matt:

Yeah.

Jules:

But I didn't, it wasn't my plan.

Matt:

right. I

Jules:

to me.

Matt:

so I want to share how I got to know you. the first time I heard about you was through Jenni Rowlings because she said my mentor, Jules Mitchell. that's when I first Googled you. at the time you were writing a book, so you were. quite quiet on social media But then your book did come out, and it was well received. A great book. Necessary reading, I would say, for all yoga teachers. I, around that time, decided to embark on a master's degree in exercise science. I shot you an email on the off chance that you might respond which you did. I basically just asked you, I have to decide on my dissertation thesis. I have to decide on a topic, and I would love your feedback. You suggested, looking at, the recent history of physical therapy, particularly in relation to language and how language has affected people I got reading about language and pain science and that did end up being my master's dissertation, all about how yoga teacher's language has potential to heal as well as to harm. So, of course, I'm very grateful to you for that.

Jules:

You're welcome.

Matt:

You did your

Jules:

It really does. I said that pleases me immensely. as the daughter of a university professor, that I was able to mentor and help someone make a decision for their path. It makes me happy.

Matt:

You helped funnel me in that direction. then I refined my own vision, of it. so I'm grateful for that initial prompt. Now, let's jump into biomechanics. We've already said the word about six times, and your book is called Yoga Biomechanics, I think we should start with the definition I know chapter one starts with this, where you talk about how when you lead a weekend workshop, you'll start by asking people what biomechanics is, and you'll get a lot of Kind of half answers and people saying is it alignment? So I would like to be the student in the front row, raising their hand, who's done their pre reading. I would like to try to define bio mechanics and then see if, if, if it's acceptable to you. Okay. Okay, so biomechanics is the study of how, hang on a second, it is tricky, especially when you're on the spot. So, biomechanics is the study of mechanics related to living systems. It investigates forces acting on and created by the body.

Jules:

works.

Matt:

a good

Jules:

Sure, I'll take it.

Matt:

So that's

Jules:

as the word force is in there

Matt:

Okay, cool.

Jules:

really about movement principles and force. that's the gist of it. So yes, I'll take it.

Matt:

Okay, cool. My daughter is just starting secondary school and she's learning about forces, so it's really cool to be studying it with her and see what she's learning about. And even learning which is cool. Okay, so all about forces, how they act on the body, how the body creates those. And why do you think This knowledge of physics applied to living systems is important for yoga teachers?

Jules:

it's a good question.

Matt:

And perhaps to yoga practitioners, could it be helpful to them?

Jules:

yes,

Matt:

Mm

Jules:

conceptually, I think it can be useful. let me back up and just say that there are divisions of biomechanics, There's, kinematics and kinetics kinematics. talks about the property of movements. And we study those already in yoga as yoga teachers. We understand what flexion and abduction are. These are, kinematic terms. We understand range of motion and joint position and things like that. Kinetics. We don't talk much about. Because that really requires force, it's not just the properties of movement, it's the forces involved in motion. And that generally requires laboratory equipment to measure. we know there's gravity, but we need numbers to calculate, right? So that's why we don't really talk about that stuff very much. Kinetics can be useful to yoga teachers, but not that useful. just maybe some general broad understanding, because we don't really have performance measures in yoga, those types of things might be more valuable if we're trying to Measure speed or jump height, like acceleration, how fast you can run, whether you can, jump over the pole, just any sport, we don't really have that. we could sit around and debate like, if you put your Foot on your knee in tree pose. what are the frontal plane forces acting on? You know, but I mean, in reality, we're not doing anything that's high enough force with fast enough motion to really move the needle anyway. that is actually an education in itself. if you're a yoga teacher, And you have all these cues where you're talking about, don't do this because it's too much force on the whatever. You're now should already be questioning. Maybe it's not, We're not really moving fast and we're not jumping. There's not a lot of, external load. compared to other things. So that led me into the third division of biomechanics, which is tissue mechanics. And that is really what my book is about. It is about the behavior, or more appropriately, the properties of our connective tissue. And that I think is where it becomes very valuable because we talk a lot about stretching and overstretching and protecting the knee and protecting the back Whenever we're talking about these terms, we're talking about connective tissue. with the weekend courses, one of the things I ask is what are some structures of the body that we care about in yoga, that we're either trying to protect or make stronger you know, people throw things out like, rotator cuff, tendon, SI joint, discs, spinal discs, meniscus. Every single structure they name is a collagen based connective tissue. And so if we're going to be centering safety and protection and healing and adaptation, we should understand how those tissues behave what they're made of, what their structure composition and how forces can help or harm them. you can be an amazing yoga teacher and not worry about that stuff. You can teach people to breathe and move and stretch and have a great time. But if you're going to start saying, don't put your foot here because you have to protect the knee. Now I would say, all right, tying our work together, that that kind of language can harm. And so if you want to change your language and you want to understand how it can harm and how it can help, it's helpful to understand how the tissue behaves so that what you're saying is actually valid. there might be a valid reason to protect a joint, but you have to understand the background

Matt:

hmm. Mm hmm. Thanks for talking about those two elements of biomechanics. during my master's I chose biomechanics as one of the elective modules that I could do. And yeah, it was because of your book. It sounded like a cool thing. Yeah, I want to do biomechanics as opposed to laboratory testing for sport physiology, It turned out to be the, the former of the two that you were talking about. It was kinetics. We were looking at forces of pole vaulters, shot putters, running with a parachute that sort of thing. I thought, this is not the kind of stuff that I thought I'd be learning about. And I did think, yeah, this doesn't directly translate to yoga in the same way that tissue mechanics would, but I found it really interesting. I didn't do terribly well at it, but, I did find it interesting It's good to know that there's a difference between tissue mechanics and kinetics and the tissue mechanics is one that you focus on more, how tissues behave. And, you know, you, um, opened The Pandora's box of foot on knee in tree pose? So, since you've opened the box, can we go there

Jules:

Sure. Yeah.

Matt:

Teachers quite often say, place your foot above the knee, below the knee, but not on the knee in tree pose. And I certainly have an opinion on this, and it's based on biomechanics, what I know about biomechanics, and newtons of force, varus force across the knee. if you can get your take on it.

Jules:

Yeah, yeah, yeah, yeah. Well, this is where enter pain science. people should put their foot wherever they enjoy and whatever doesn't make them feel unstable, feel, you know what I mean? Like, feel, sensitized. So, somebody with arthritis, with osteoarthritis, might not like the feeling of the foot on the knee, right? Somebody might not mind. but regardless, if you understand, cartilage degeneration, which is a tissue mechanics thing, cause it's collagen based, you'll realize that putting the foot on the knee is not going to do much to the knee. you're not kicking your knee as hard as you can. You're not strengthening the muscles of that standing leg with external load. You're not doing squats with a barbell on your back in that tree. you're not really adapting. You're not really damaging. You're just kind of putting your foot there. so the question now becomes, does it feel good or does it not? And of course, if you're interested in range of motion, which a lot of yoga teachers are, you put the foot above the knee because you're trying to get the foot as high as you can. That's a valid reason too, but if somebody doesn't have that range of motion, do they need to put it below the knee for any reason? Like these are, it's all subjective, When we're talking about minimal forces, It it doesn't really make that much of a difference. you can tell people not to put the foot on the knee because you have a class where you suspect some people might be sensitized in the knee and this isn't good for them It's the way we say it with this certainty that the knee can't handle it, and the knee can handle it. in the book, I cite a paper where I looked at frontal plane forces on the knee, just walking down the street has higher frontal plane forces on the knee, you know, than you would see in some yoga poses. So it's going to be okay. just say, put the foot above the knee. you don't have to validate it with some fear mongering message that, over years of doing this is going to damage your knee joint. You know, what does that do to someone's beliefs? And then they, 10 years later, find out they have arthritis and now they're blaming yoga for it.

Matt:

Yes.

Jules:

you can pull on that thread

Matt:

I don't like the fact that that cue suggests that our knee is really vulnerable. When in fact, like all of the other joints and structures of our body, they are well built. And if we just look at forces, and correct me if I'm wrong, but when we're running, we can have three to eight times their own body weight traveling through the knee

Jules:

Instead of transversely from the frontal plane.

Matt:

which is what I was going to mention in the act of cutting, which is what soccer players do. They're running one direction, they change the direction. That is going to send a frontal force through the knee of their own body weight, times whatever speed that they're traveling at, So, we are going to see forces greater than just the weight of the leg, without moving, being placed onto the knee. And potentially not even the whole weight of the leg, you might be using your hip flexors to lift the foot off the knee a little bit too. So, I think when we take it into context, also consider kickboxers who take huge forces to the knee and they manage to do that. so it's really important to remember that the body is an adaptable structure. It's a strong structure. and it's not as weak and vulnerable as I think we can sometimes be led to believe.

Jules:

And let's take a yoga example. cause I love, I do what you do. I always to sports and things like that, you know, but then some people are like, athletes get injured too. I love those examples. And in my slides, I have tons of, athletes doing incredible things, hockey players, and tennis players but let's just take a yoga example. if you're standing in Tadasana, you're standing in Mountain Pose. Now we've got longitudinal forces going through the knee, ground reaction forces. if you stand with your feet wide. now this is where a little bit of physics comes into play in my biomechanics course, I draw arrows and show force and we talk about this in more detail, but maybe you can envision it. if you stand with your feet wide. your knee is not right over the ankle anymore, if you understand anything about geometry and maybe some trigonometry, you can draw a right triangle from where the foot is making contact and the knee, and you can calculate some frontal plane forces on the knee. And I would, need real data to measure that. So I'm, I'm speaking hypothetically here, but for many people, those forces on the knee are actually more than just resting your foot gently on your knee and tree pose. So in yoga, we are already exposing the knee to greater loads than in that situation. Think of side plank. That's a great example. If you're, if the outer edge of your foot is on floor, right? Or think of the back foot in warrior two versus the front. In the front, we'll say, make sure the knee is over the ankle, but in the back, it's not. So we're talking out of both sides of our mouth, my favorite, if we talk about the shoulder. There's plank, you know, we want to keep the shoulder over the wrist and plank. And then the next pose is Chaturanga. And now we want the shoulder way in front of the wrist. this is where tissue mechanics comes into play. it's not that you need to know the exact forces and need to know the exact numbers but you should understand these basic principles. Because otherwise it's really hard to deconstruct your language. It's very hard to deconstruct the initial script that you've been given because the initial script was given in assumptions. now if the body's just adaptable, I don't know what to say anymore. And then you feel like you don't know how to teach anymore. But if you understand these ideas, you get more confidence and you can, deconstruct those messages and come up with new ways to say things. That's my direction in teaching people this.

Matt:

Beautifully said. Going back to my last podcast episode with Libby Hinsley, she said, there's nothing wrong with defaulting to comfort. Helping the people in your class feel a little bit more comfortable. You in your own practice feel a little bit more comfortable. Great. That's probably a good idea to have less pain, in a certain pose. Okay. Go for that. Then don't add on the extra bit. about how, such and such a joint is vulnerable or weak

Jules:

Yeah,

Matt:

So, you talked about how some knowledge of science is useful, right? how much science do you think all yoga teachers should be science literate? research literate? I know this is where your forte is. obviously, You're gonna think, to some degree, yes, but how much science do we need to know as yoga teachers?

Jules:

Oh, that's such a good question. Research literacy is like my, I teach biomechanics. Research literacy, like it's the second thing I teach as far as, my curriculum. people will be surprised to say that actually as a yoga teacher, you don't need any of that. I think if I were to walk around and say every teacher needs biomechanics and every teacher needs, scientific literacy, that's a very, arrogant, upholding, supremacy and patriarchy and all of that, So nobody needs that. if you're interested in it, I'll help you, like, I'm interested in it. I don't think anybody needs it. people can be amazing, lovely yoga teachers that teach breathwork and mantra and, and kirtan and what they never even mentioned the knee, you know what I mean? Like, why would I say that? Oh, you know, like, I think there's so that's one of the great things about yoga is there's so many approaches. But if you do like to teach an athletic style of yoga that really focuses on joint position and angles, then you might find this stuff really interesting. you might be surprised at how confident you become because most of the messages have just been like, Rote memorization, I remember I learned what a tendon was and it connects muscle to bone, you know what I mean? that's what I learned. but once you understand the histology of a tendon, it gets really interesting, once you understand tendinopathies, you get really interested, so you might like it. I think no one needs it, but it's available if it interests you. go down that path because it's fun. as far as research literacy goes, the same thing. research literacy and, and kind of evidence-based teaching, you know, is having its moment. but the, the problem with with that is it very quickly becomes a weapon. To prove that you're right. that is actually not what research literacy is. and not what evidence based teaching is. it's just the way the human brain works. we want to find reason and we want to be right and we want to know. but that's not how it works. if you are interested in research literacy, my suggestion is buckle up because it's a lifelong journey of understanding what can be studied, what can't be studied, what is studied, why we have multiple studies with different results, it helps you form a greater understanding. instead of saying that this is the right and best position for plank pose. That's not what science does,

Matt:

hmm.

Jules:

I think that's what Libby said on the last podcast there's nothing wrong with. encouraging your students to be more comfortable. that's not a scientific statement and it is a valid way to teach. everything doesn't need to come from a research paper. that statement comes from a deep understanding of these concepts. I think what happens is people think research literacy means that a study was published and that twisting makes you do this. then you come into your class and twisting does not, detoxify you become like, all of a sudden you have all this knowledge, you know, and that's not it. what you get out of scientific literacy is, I'm going to teach twists and See how people feel and let them have their experience. I'm not going to make wild claims about what it does. I don't even need to spend my time invalidating what somebody else said in a previous class. I think we end up being like, any yoga teacher that tells you that twisting, da, da, da, like there's so much, we don't know, you know, just chill out.

Matt:

Mm hmm. Yeah.

Jules:

does that give you an of how I feel about research literacy?

Matt:

Yeah, absolutely. So it's there if you're interested, but maybe we don't need to. But at the same time, you have to go down that rabbit hole to then realize what you're doing in the first place was right, you know?

Jules:

Yes. That's what I by it giving you confidence. Do you know what I mean? it supports a larger narrative that you could be a great teacher already, but you're not quite sure. you're not really Behind what you're saying Completely. And this helps you do that.

Matt:

if a yoga teacher came to me and said, should I teach handstand, I would say, yeah, go teach handstands, you know, and then if they then ask the question, okay, are handstands safe? Is our shoulder joint built for handstands? How many handstands should I do before I get injured? Well, then we have to go down that whole rabbit hole. We have to look through all the research, whole journey of the body to understand tissue mechanics, like you're talking about, adaptation, to then arrive at the conclusion that, yeah, you should go do

Jules:

Yes, Exactly. And I'm really, go ahead, I'll finish and then I wanna add to that.

Matt:

And just basically, don't worry about it, just do what you need to do to get into your handstand and keep cracking at it, you know?

Jules:

Yes, 100%. So what I was gonna add was what I love that you mentioned that you have to go do this whole like journey of research and I think that is. That's where I, when I said buckle up, it's a long journey for research literacy. I think what happens is people get a little bit of exposure to science and then they just use this single study. They find a single handstand study where somebody this and that and use it to validate whether handstands are good or bad when in reality Being scientifically literate, and I'm using that in air quotes.'cause even that is sort of an arrogant term. But that means that you've spent a long time on a single topic and you're very familiar with the research of the last decades and the research that's coming out today. you're more interested in the questions that the top researchers are asking than the results of a single paper. you're following the trends. you're aware of new technologies that are allowing us to study different things in the shoulder joint for handstand. Like now we have fluoroscopy machines and we can measure, you know, 0. 4 millimeters of movement inside the shoulder joint. And so you're, you know, You're becoming very well read on an entire topic and then you arrive at, yes, you should do handstands, you know? And I, but that's the important part it's, you're in it for the long haul. And actually, that's not satisfying for some people. but it's very satisfying for me. You know, it's like, I don't ever, it's very yogic to me. I don't ever want to be finished with downward dog. I want Downward Dog to be something novel that excites me every time I do it. I want a certain topic of study to constantly be, surprising me and constantly be informing me and holding me to, you know, challenging my own biases. They go hand in hand to me.

Matt:

Yeah, and I think we both arrive at that conclusion that science is great, science is interesting, but there's nothing quite like the magic of yoga. And I'm on your email newsletter, you recently said something about refinding yoga. the magic of yoga. And there's something that can't be described about it, that can't be understood. There's just something great and magical about it, and we don't have to have all the answers. And onto your topic of understanding questions, or looking deeper into the questions, Richard Feynman, the science philosopher, said, I'd rather have questions that cannot be answered than answers that cannot be questioned. Which is a great quote about basically holding our firm beliefs lightly. and our light beliefs firmly being open to the idea that we can be wrong, science will be wrong, things will evolve, we'll learn new things. You know, 50 years ago, we thought loading the spine in flexion was the best thing for people with osteoporosis. And then we found out, okay, it's not the best thing. Let's not say never do it. Please don't leave this podcast episode here. Oh, you must never round the back. No, it's more loaded flexion. And it's more the science found An exercise regimen characterized solely by spinal flexion exercise is probably not the most beneficial. You should get some, extension exercise in there and lateral flexion and stuff. indeed, we do learn new things. Information does change, or at least what we hold true does change from time to time. Not to say. We're in the post truth era, you know, there's still

Jules:

And it also, you know, it, it depends. I know that's a hard thing to understand, but it depends on what, who, it depends on, you know, loading history, it depends on genetics, it depends on da, da, da, you know, there's so much context and nuance, that is, Missed in some of those statements. it's not necessarily our responsibility to understand the context and nuance for every single individual, but it is important to understand the context and nuance for, you know, a large group. So again, it has you speak differently. It has you come from going back to that, Libby quote, the comfort, you know, like that's, that's okay. You can, you can always fall back on that instead of this yes, no, hard line in the sand, we as a society prefer the hard line in the sand because it's easier. It takes out the context and nuance, and this is exactly what public health does. Public health says, okay, cholesterol 200. Below, you're good. 199, you're good. 201, I'm prescribing you drugs. and that, you know, like, and I understand that we have to do that because otherwise it's chaos out there. But we don't have to operate as public health officials. We're offering people an experience in a yoga class to sense their bodies and feel. So we don't, We don't have to be so rigid,

Matt:

Great point. speaking of the rabbit hole of research, I'd like to ask if you could share any interesting things you've found I know you run a science of stretching seminar and you're, you're constantly looking at the latest research on stretching. And if you're thinking, well, stretching yoga are different things, yes and no, in that yoga is so much more than stretching. But if we just look at the tissue mechanics, yes, stretching is what is happening in your body when you're doing yoga for the most part, especially things that end range of motion. So, any interesting things on, stretching research?

Jules:

Yeah. so I do that webinar twice a year, and, it just evolves each time. It's only three hours. I follow a very firm, one in one out rule where if I add a slide, I'll run out of time, so I have to remove a slide, so you're always getting new research, but the central narrative is pretty similar. even that has changed over the years as I've separated work, but, um, I'm always looking at stretching research and you're kind of catching me like right in between cause the next one's in January and what my strategy for that, just if people are interested in how I manage my research literacy is I get an email every Monday morning. with a topic that I'm interested in. So one of those topics is obviously stretching. So I scan through and any of the papers that catch my attention, I flag. And then, in the weeks before the, so I'm aware of what's going on, but I haven't done a deep dive into them. I do that the weeks before and decide if it goes into the, if it makes it into the, into the, slideshow or not, you know, whether it's interesting. So I always have my finger on the pulse. And I think the two biggest topics right now that I find really interesting in the stretching world are pain, and hypertrophy. Those are like the two big topics. so let me just kind of talk about the pain one. so we've understood that one of the things that limits range of motion is something called stretch tolerance, which is our ability to tolerate the sensations associated with stretch. we've kind of known that since the nineties, I could speak for hours on it and I'm not going to, but, uh, but, but yes, we've known that for a while, but we really haven't understood like how that works. Now we're onto the neuroscience of stretching. what's happening there? I kind of joke lovingly that, neuroscientists have way more important things to research other than range of motion because

Matt:

Mm

Jules:

I hope all of our neuroscientists out there aren't spending all their time on range of motion because it's not that important. So, so that's kind of one of the reasons why it's been a very slow, progression of how does stretch tolerance work, you know?

Matt:

Of

Jules:

do it again.

Matt:

they're going to look at Alzheimer's, dementia, these sorts of things. Like, how can we prevent these things, slow these things? And yes, that does

Jules:

Important things, important things that really help. Yes, exactly. as more neuroscience is being studied, there's more information and And so I think in the pain science world, we've learned a lot through some neuroscience there as well, because we, you know, we're learning about the biology of pain and biology of learning

Matt:

hmm. Mm

Jules:

And now there's some really interesting studies coming out that are looking at. different ways of kind of tricking the brain so that you can improve range of motion. And it's not like they're not doing it because more range of motion is better. They're doing it to try to understand how stretch tolerance works, you know? And so they're, you know, they've got like, out of Scandinavia, they've got a couple of studies where they put a hand. your hand in ice cold water, like zero, one degree Celsius and expect that your, that your brain basically, creates that descending inhibition that it kind of floods your body with chemicals so that you don't sense it. And then they have greater range of motion, which is kind of interesting. Now that doesn't again, this is about research literacy. That doesn't mean that you should now have all of your yoga students put their hand in cold water for Supta Padangusthasana. the research isn't trying to make people more flexible. The research is trying to figure out how this works, it doesn't have an immediate application and that's unsatisfying to people. Sometimes people leave my webinar and they're like, So now what? I'm like, just keep teaching the way you're teaching.

Matt:

Yeah,

Jules:

it's just interesting stuff. I'm always reviewing research in my mentoring program. That same team did a really nice systematic review on stretching for people with fibromyalgia and whether or not stretching helps them with their pain. So it kind of goes the other way now. It's not looking at range of motion, but can we use the What understanding how the brain responds to stretch sensations does that maybe also create some descending inhibition and then inhibit some pain? So, That big broad topic is very interesting to me right now. you can expect to see more of that in January.

Matt:

potentially listeners listening to this, you're referring to January 2025,

Jules:

it's every January and July,

Matt:

every

Jules:

every January and July. it makes it easy for people to plan. I always have two up. You can even set for next January as well, 2025, but it's easier for everybody if we just stay on a calendar. yes.

Matt:

Great.

Jules:

and then the other topic is hypertrophy, which is something we call stretch induced hypertrophy, which is if you stretch under specific conditions, um, which is extreme, uh, but you can actually, hypertrophy is build muscle and it's longitudinal hypertrophy, not cross sectional area. So you're not getting swole. And that is a really interesting topic to me because I've been reading, stretching research for 12, 14 years in that range now. And the subjects, the opinions have changed massively, you know, back the early 2000s. 2000s. Early 2010s, there was just a lot of stretching is dumb, stretching is bad. Stretching makes you weak, stretching makes you slow. that research is now in the mainstream. And I'm like, yeah, I mean, we have research for that. but there's a little extra stuff happening in the world of researching what titin is and how titin plays a role and how mechanical tension is the driver for hypertrophy, which we understand from resistance training. And so now we're seeing that, under certain conditions, we can actually, Get longitudinal hypertrophy. what does that mean? Does that mean that you should go out and stretch everybody in their yoga, yoga class to your maximum end range? No, that's not what this is. You know, it's just really like, Oh, what a cool thing that we're actually understanding muscle physiology on a deeper level. I remember reading about titin, the, protein like actin, myosin, titin in 2013, 2014. there were four different hypotheses and all of research groups would write letters to the editor of the journal to say why that's not a good hypothesis and why theirs is better. I remember like, And here we are 10 years later, and we actually have a leader of the pack. We have a hypothesis that's been, replicated and validated. it's really fun to watch that growth. Like I remember lecturing about titin in 2014 in my courses it was so uncertain at the time that I ended up taking it out because like, didn't really help a yoga teacher anyway. And now it's back in because we know so much that it's worth lecturing about again. I'm really excited to see where that goes in the next five years.

Matt:

Yeah. So when I teach in a teacher training program and we're covering the muscle tissue module and we're looking at sarcomeres, I only mention actin myosin so as to not bog people down. can you share what is that leading hypothesis on titin?

Jules:

We've always known we've had titin but it's always been considered very passive, which it actually, you know, it is passive. But, there are some papers that say, we should update our sliding filament theory and call it like the three filament model, because titin does actually play pretty huge role. It interacts with actin directly and calcium. but when titin gets stretched. To long lengths, it actually has very high stiffness and that stiffness is that mechanical tension that promotes longitudinal hypertrophy. I'm being very careful not to say sarcomerogenesis. I'm, I'm very, being very careful to say longitudinal hypertrophy because fascicle length, like that's still for me, there are people that have strong opinions one way or another, but for me, there's not enough information and not enough Science behind it for me to make a strong statement. So, how the longitudinal hypertrophy exactly occurs, we're totally not certain. Again, these are just limitations of technology. Once we get better technology, we will know. It's just, we need advancement to happen. But so, titin, it really increases the mechanical tension within the sarcomere, and that's The mechanism. And what's so interesting is it answers a lot of questions. if you remember, studying early in school, concentric contractions versus isometric contractions versus eccentric contractions. we really didn't have a way to explain why eccentric contractions were such high load contractions, why we could tolerate so force, even beyond crossbridge formation. We had no way of explaining that. I remember my college professors just being like, yeah, yeah, yeah, Eccentrics. Okay, break time. You know, like they didn't have a way of explaining it. So they just didn't cover it. And now we actually understand that it is titin. We have a way of explaining it. I think it'll be a while before it shows up in textbooks and in classrooms, but it's pretty cool.

Matt:

And that can also be, why less energy is required,

Jules:

yep. It's that passive mechanical tension. And then, of course, it depends. So, it depends under certain conditions and, and titin, because it's viscoelastic, doesn't have linear behavior. And so, it has to be in like the, the, stretched phase. And so, Your stretch tolerance might not ever get you there. So that's why we might not see consistent results across studies. and also there's no way of knowing, you know, where that person is because of genetics and, it's going to vary among people and it's going to vary among muscle groups, like the quads and the biceps might be different. And so, yeah, it doesn't change the way you teach yoga, but it's cool information.

Matt:

We've very much gotten into the weeds here, haven't we? And yet, it's fascinating. Again, it won't change yoga. You know, what's the best kind of yoga? The kind that has been going on, and keep doing that, you know?

Jules:

But it will change the way you say stretching at end range is bad or stretching It will change your language

Matt:

I don't say that.

Jules:

Yes.

Matt:

I don't say that.

Jules:

but there are people you know what I'm saying?

Matt:

yeah, absolutely. And so that's why it is important to learn about this stuff so we have a better knowledge of how the body works, and we can make more informed decisions. Both, in terms of medicine and helping people who are not well or who are injured, but also improving performance or function or just because it's fascinating to know. And, you know, you know, people study astrophysics, not because it's helping us here on earth, but just it's cool. And that's great. on to a different topic altogether. Hamstring tendinopathy, Jules. So what's commonly known as yoga butt this idea of what is more correctly referred to as proximal hamstring tendinopathy. it is often associated with yoga, but so far, it seems, on an anecdotal level, I don't think as of yet, there's great research to show that yoga contributes more to hamstring tendinopathy than other forms, and interestingly, people who are sedentary can have this hamstring tendinopathy, and it basically presents as a feeling of soreness. at the bottom of the buttock, perhaps worse when stretching. I've looked at the research and I have actually Holger Kramer scheduled to come

Jules:

Oh, nice.

Matt:

the podcast. and he's done a lot of research on yoga injuries, how safe yoga is in relation to other forms of exercise. of course, research is just one small lens of a larger picture, but based on my reading of the research, hamstring tendinopathy has not shown as more common than other forms of injuries or, adverse side effects in yoga practitioners. So my questions for you, do you think it's more common? If so, why does it happen and what should we be doing? if load helps tissues recover, why is it that, stretching might aggravate someone's hamstring tendinopathy and yet increasing the load by doing strength training will actually help it. Can you help us decipher that?

Jules:

Oh boy. This is a big question.

Matt:

I know.

Jules:

It's like an hour of one of my workshops. Um,

Matt:

Well, the, Mmhmm. Mmhmm.

Jules:

Um, let me start with yoga injuries, incidents. I think we have a lot of research on it, but this kind of research is very hard to make sense of because they're mostly done by surveys. Which require recall and surveys are just not the best way of doing research. and so you always get this wide variety of things, you know, I mean, I've done webinars on all of these. Synthesizing all of that safety research. there are going to be some things that stand out more than others and, hamstring tendinopathy is not one of them. you're right about that. but tendinopathies in general as a, that is a category that is prevalent. The thing is with those surveys, there's really no cause and effect relationship that comes out of that kind of data. People get tendinopathies. Just from being sedentary, like you said, sedentary people get hamstring tendinopathies. So do sprinters, and so do hurdlers who do end range things and so do sedentary. So The reason we call it tendinopathy and not tendinitis is because the only thing that needs to be present in a tendinopathy for diagnosis is pain, You don't need a histological examination. I got a thing in my ankle for no reason. I just appeared one day, you know, but if, if all of my activity is yoga, I might relate it to yoga, right? so these Types of studies where we're just collecting information from populations. good information, but it's very hard to say yoga causes labral tears like we like that. The, the type of study you would need to do would be, you'd have to control so many factors and you'd have to follow people for 30 years. The researchers wouldn't even, they'd be retired before the study was done. You know, It's just hard to collect that kind of data. And there's another study that actually looks at what goes to a radio. I talk about it in my book. Um, goes to a radiography center and scans the past 10 years for the word yoga, they look at a scan, but even that is hard to be conclusive. Let's just say, for example, I have a rotator cuff tear on my right side. my shoulder never hurt. I just found it on accident doing an MRI for something else. Okay. I can do everything. I do overhead presses. I do handstands regularly. I play tennis and it's my serving arm. I play tennis five times a week. I have zero pain, zero limitations. I just happened to have a rotator cuff tear. Let's say I didn't know that. And all I did was yoga. And I went to a sweaty class and did Pinchamayurasana, forearm stand and slipped and my shoulder hurt. And I went and got an MRI and I have a rotator cuff tear. Would be very easy for me to conclude that it was caused in the yoga class. But if I didn't have an MRI before the adverse event occurred, then how do I know? And if you look at tendinopathy research, you really understand that tendons have a metabolism. There's high turnover and, So this is already a really complicated topic, as you can see. so it is what it is, you know, there's no way of saying that the yoga causes these things, but now we do care about certain things in yoga. We do care about shoulder pain. We care about, I hate the term yoga, butt, but you know, we care about proximal hamstring tendinopathy. We care about it when people have sitting bone pain, So now what do we do about it? What is it caused by? Well, again, without a histological examination, without pre and post imaging, how the hell would we know I don't know what it's caused by. Is it caused by a high tendon metabolism? we have an understanding that people with higher tendon metabolisms are more prone to tendinopathies because the metabolism means synthesis and degradation, and it can go both directions. Do you know what I'm saying? so much there. So how do we work with it? Well, let's just not sensitize them more. if deep forward bending sensitizes the hamstring tendon, don't do it. Back off for a while. Okay. Now loading is also good, right? So you said, why is, why is heavy loading better than stretching? Um, I don't for certain know that it is. the research and my bias says that it is, but I don't know that it is. That tendinopathy could resolve on its own through maybe gentle stretching. I've heard people say Yin has helped them. So I don't know. But my bias,

Matt:

Well I think, I'm not a physical therapist of course, but I think a standard action when someone reports having hamstring tendinopathy is to go about trying to strengthen the hamstrings. Once things have settled down, and so I think that's why, you know,

Jules:

because that is the protocol in the research.

Matt:

yeah.

Jules:

the reason that would be different than stretching is because when you actively contract the hamstring muscle, it's going to pull on the tendon. So it's going to be higher tension on the tendon. And this is, I think, where people struggle to wrap their brain around it. if you're doing a really heavy lift, you're putting more tension on the tendon. Well, isn't that stretching the tendon? so now you're saying that actually heavy stretching is what the protocol is, cause that's what loading the hamstring is, is putting high levels of tension on the tendon. So that's where I had to say, I don't know. it may be not that stretching itself is the aggravating factor. Because if you just do a passive stretch, that's lower load tension on the tendon. it might not be worse It might be just not enough to produce an adaptation. but in some people, maybe it desensitizes them. I don't know. So, I do have a theory and we have some research on it, but I'm always cautious when I say this because it makes people think end range is bad and end range is not bad. But I do think that when you're in very, very deep hip flexion, the tendon sort of wraps around the bone and gets some lateral compression forces. and that happens when you're sitting a lot people that sit a lot tend to get hamstring tendinopathies and a lot of end range people tend to get, tend to get them or end range activity, people who do end range activities. And so maybe that's a part of it. maybe it's not that the stretching is what makes it worse. It's like we're constantly going to end range, just kind of resensitizing it. So maybe gentle stretching where you back off a little, which, you know, again, depending on your stretch tolerance. If you don't have, if you don't have end range, then it's not even an issue for you, right? So like, you can't just say stretching across the board isn't as effective. I just think it's a lower load intervention, I guess is what I'm getting at. but we don't have studies that look at all of these things. So that's where I'm at. I don't know if that answers all of your questions. it's really hard to do a cause and effect. Again, we're not physios, so I try not to give physical therapy advice, my approach is my job as a yoga teacher. And your jobs as yoga teacher is to give people their yoga back is that is to teach people the poses and have them do the poses they like and have the poses. that bother them, make them doable for them. So for some people that's going to be engaging the hamstrings in a forward fold. For some people, that's going to be backing off end range. For some people that's going to be, you know, that, that, that, you know, only doing a standing forward fold with the upper body supported on blocks, hands on block. You're going to have to figure that out with your students. if they really want treatment for a tendinopathy, they should go see someone. You're just trying to help them do their yoga.

Matt:

Exactly.

Jules:

my take on it.

Matt:

in a teacher training, I would say, what does this yoga teacher certification certify you to do? There's a bit of a pause

Jules:

hmm.

Matt:

teach yoga. and let that be liberating information that you don't, need to, you're not expected to solve everyone's problems

Jules:

And you can teach yoga to people with tendinopathies without the, you know, direct, like I'm, I'm treating you, you know, it's just like, okay, let's, let's get you back to forward folds. It's going to be a journey. this is where tissue mechanics helps. Understanding tendon, tendon, like if you followed this whole conversation, you know, I said a lot of terms about mechanical tension and, you know, like, this is helpful, it helps you troubleshoot, it gives you the confidence to, Provide a suggestion at the end of the day. The person gets to tell you how they responded to that high load, low load, end range, whatever. And then you work together so that they can continue to come to your yoga classes and do their forward folds.

Matt:

Great. that's a nice finishing point.

Jules:

Yeah.

Matt:

So, Jules, I think listeners, if they didn't catch all the terms,

Jules:

Mm

Matt:

I think they'll definitely know, wow, this is a smart woman. She knows what she's talking about. And if they're thinking, I want to study more with her, what should they

Jules:

Just go to my website, julesmitchell. com. I have so much stuff there. I'm constantly running courses.

Matt:

And I'll include that in the show notes, but could you share it now also?

Jules:

oh, julesmitchell. com. Just my name, just J U L E S julesmitchell. com. If you just type in yoga biomechanics into Google, you'll land on my site. So,

Matt:

That's right. You're easy enough to find. And you're also on the socials,

Jules:

Yep, I'm on the socials. Yep. Yep. Jules yoga is on Instagram. That's why I'm the most but Yeah, I'm on the socials.

Matt:

any closing thoughts you'd like to share

Jules:

I am doing What I call a book club. I know you guys do a book club as well I kind of stopped doing them because I got tired of doing it over and over. But people are still finding my book and so I'm offering it again. And so that's coming up in January and I'll probably do one a year, moving forward. if you want help, reading my book. you read one chapter a week we do one hour on Zoom a week you submit questions in advance and I give you study questions I really help you make sense of all those graphs because not everybody likes geometry and graphs,

Matt:

Yeah, exactly. Same with our book. It just helps you get through the book because otherwise it's one that just stays by your bedside. You're like, Oh, I'll get to it later.

Jules:

And, and I hope, I help you make meaning of it. I hope you put it in context of yoga, which is where the book doesn't have that because it's hard to write a science based book and make meaning because then all of a sudden it's not science based anymore. so the, the, you know, the, the casual nature of the conversations are where we kind of tease out what it means and what it doesn't mean and all of that.

Matt:

There's nothing like a human telling you what the research is saying, because it's so much easier to grasp it, to understand it. I should also say perhaps an AI bot, because they're getting as good at summarizing it, And perhaps we can save, that for another chat for another day. Um, but Jules, I feel like I get smarter every time I talk to you. So thank you so much for being here. Thank you for being generous with your time. I really appreciate it. And I look forward to keeping in touch with you.

Jules:

Thanks for having me.

Matt:

awesome. Thank you very much.

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