Enlightened Anatomy with Matthew Huy

5: Bernie Clark on Yin Yoga, Fascia, and Your Spine

• Matthew Huy • Episode 5

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In this episode, Matt interviews Bernie Clark, author of Your Body Your Yoga and other books, discussing his journey into yoga, his influential works on yin yoga, and his deep dive into human anatomy and variations. They address the scientific and experiential aspects of Yin Yoga, the importance of stress and rest on tissues, and the dynamic nature of pain and recovery. They also touch on the evolution of yoga therapy and the nuances of teaching yoga with a focus on individual variations. The episode includes insights into how anatomical differences impact yoga practice and refutes common misconceptions with a critical and informed approach.

Resources mentioned in this episode:


00:00 Introduction and Welcome

01:11 Bernie Clark's Journey into Yoga

02:34 Discovering Yin Yoga and Human Variation

03:47 The Importance of Anatomy in Yoga

14:07 Challenges and Evolution in Yoga Teaching

23:54 Yoga Therapy and Scientific Validation

32:53 Understanding Muscle Tension: Hypertonic vs. Hypotonic

33:11 The Role of the Immune System in Muscle Stiffness

33:51 Hormonal Influences on Fascia and Injury Risks

34:22 Tension vs. Compression: Limits of Flexibility

35:02 Personal Experiences with Compression and Injury

36:35 The Reality of Physical Limitations in Yoga

37:47 Debunking Myths: Yoga and Bone Structure

38:57 The Debate on Fascia and Yin Yoga

40:35 Targeting vs. Isolating Fascia in Yoga

42:00 The Science Behind Long-Held Yoga Poses

51:04 Stress and Recovery: The Key to Tissue Health

57:25 The Controversial Credit Card Analogy

01:04:56 Final Thoughts and Current Endeavors



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Hello, welcome to the enlightened anatomy podcast. in today's episode, I interview Bernie Clark. And if you don't know this legend, he has authored many books amongst others, a trilogy called, Your Body Your Yoga, that examine how your unique anatomy might affect your yoga practice. So we cover a lot of topics, including whether yin yoga truly targets the fascia. And I dig deep with Bernie about the controversial claim in some of his books that the spine is similar to a credit card in that if you bend it too many times, you can weaken it. So, as you can hear from this episode, Bernie is a super smart guy and he has brought his knowledge of physics into the realm of yoga anatomy, and physiology. I have tons of respect for Bernie and after having an IT issue on my side at the beginning, I was a bit flustered when we got started. And so I called him by the wrong name. I called him the American politician, Bernie Sanders, instead of Bernie Clark. And I was going to edit that out, but then I thought, heck, let's keep it in. So thankfully Bernie Clark, not Sanders was very gracious about it. One last thing. If you're enjoying this podcast, please be sure to subscribe. And honestly, if you could leave a review, I read all of them and would make my day. I put up these podcasts and I didn't really know how they land, except when I see people in my classes who say they're enjoying them once someone at a yoga festival. So one way to say thanks if you're enjoying it is to leave a review. So thank you. And now on with the show,

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.

Matthew Huy:

Hello! and welcome, Bernie Sanders. Oh, Bernie Clark! How many times have you had that? I'll start over. Has that happened before?

Bernie Clark:

no.

Matthew Huy:

Okay. Oh gosh, sorry. Okay. Okay, here we go. Hello and welcome, Bernie Clark, author of, amongst others, Yin Yoga, Your Body, Your Yoga, which includes a trilogy, of course, So, thanks for being here, Bernie, and, um, it's, it's truly an honour to have you here.

Bernie Clark:

Thank you, Matthew. It's a delight to be here.

Matthew Huy:

And, you wrote a little testimonial to our book. We sent that to you in advance. And you wrote very kindly a note for that. So thank you also for that. It's my first time actually getting a chance to thank you.

Bernie Clark:

it's a great book and really happy you guys wrote that. I think it fills a wonderful niche in the kind of the universe of yoga books. There's nothing like it, so. Congratulations.

Matthew Huy:

Ah,, well, thanks, Bernie. Yeah. As you know, it's, it's a lot of work writing a book, isn't it?

Bernie Clark:

Yes.

Matthew Huy:

has to be a labor of love. So I just wanted to start first by asking you about your background. so how you got into yoga and, and, and also how you got into writing about yoga and of course, yoga anatomy.

Bernie Clark:

Sure. Um, I guess I got into yoga, although I didn't realize it could be called yoga at the time in my early 20s. I took up meditation to help with stress in the workplace. I was in the sales and marketing industry. I eventually joined a high tech space industry company in Canada. I have a degree in physics from the University of Waterloo. So I've always had an interest in the sciences and how the universe works. But even as a young child, I was always very curious about mythology, religions, spirituality, psychology, and how the mind works and so forth. So I always like to build bridges between these two different maps or models of the way the universe unfolds. In my 40s, I took up asana practice. I got into it basically to help my meditation practice. So for the last 25 years or so, I've been teaching yoga and meditation. It's just a chance to bring these two worlds together.

Matthew Huy:

Brilliant. And you're calling from the West Coast, right? Where exactly are you based right now?

Bernie Clark:

I'm in Vancouver in Canada.

Matthew Huy:

Yeah, And you were born and raised in Canada, right?

Bernie Clark:

Yeah, that's right. Native here.

Matthew Huy:

And so you've specifically been drawn to yin yoga, is that right?

Bernie Clark:

Well, I got started with, my first teacher, Shakti Mai. She'd come through the Sivananda tradition, and although she left the Sivananda world, there was a strong theme through her teachings that were informed by Sivananda, but also through Zen and other things. So she was my first teacher. introduction in yoga, but very quickly, I discovered Ashtanga. And so for many years, I was a real driven Ashtangi, getting up at, uh, you know, ungodly hours in the morning to do the Mysore practice six days a week. And after several years of that, I just happened to run across Sarah Powers. Who was teaching yin yoga. And through her I met Paul Grilley. And that just rocked my world. Because in, not so much in the Sivananda tradition, but in Ashtanga and some of the Iyengar traditions, there was a big focus on getting people to look a particular way in a pose. Alignment was king, and we wanted the whole class to look identical in down dog or warrior pose, and we were very fussy about where the knees should line up with the front foot or the back foot. And then I met Paul and realized, all this made no sense at all. And that, that triggered my interest to get deeper into the anatomy section of yoga, and I kept telling Paul He's got to write a book on all this because human variation is so important. Now Paul he's done DVDs and he's done online seminars, but he's not much for writing detailed books The books he has written are wonderful, short, 80 page type books that really help to illustrate the ideas. But when I wanted to know the nitty gritty of exactly how does the ulnar curve vary from person to person, he wasn't into that. So he said, well, you write it. So eventually I took him up on it and it took me eight years to write that trilogy, even. It was like going back to university and getting a whole other degree. But I just had to document the way everybody is different. And most of the books out there on anatomy really are muscle books. They talk about which muscle moves which limb. But I wanted to get deeper than that. I wanted to get to the bare bones of yoga anatomy and figure out not only how the bones affect our motion, but how our bones are all unique. Everyone's unique. Even the concept of a bicep. We like to think, well, the bicep has two heads. Well, that's for most people, but not everyone. Some people have a bicep with three heads. Some people have triceps with five heads, so human variation is such an important part, but it's kind of glossed over in the yoga world,

Matthew Huy:

Yeah, absolutely. And that's been picked up in the scientific world also. I've seen a paper talking about the quadriceps and, you know, of course, quad means four,-ceps means head, so biceps, two heads, quadriceps, four heads, and how the quadriceps can also have multiple different amounts of heads, so perhaps a better name would be, you know, multi-ceps or

Bernie Clark:

The polyceps.

Matthew Huy:

Yeah, yeah, exactly.

Bernie Clark:

had students who had no pectoralis major muscle, so to think that all these muscles that we learn about in these muscle anatomy books, they're not the end thing. That applies for most people, but not everyone. Like a lot of people who study anatomy think we have five lumbar vertebrae, 12 thoracic vertebrae, 7 cervical vertebrae, so we have 24 vertebrae in our spine. Which is true except for those who don't. There's about 5 percent of the population that will have one more or one less lumbar vertebrae. And since the lumbar vertebrae dictate how much flexion and extension we have, somebody who's got six might be naturally more flexible than someone who only has four.

Matthew Huy:

yeah, exactly. Yeah, I had a private client right before I met you, and she was saying, so who is this Bernie Clark guy? And to summarize you, I thought, if I could summarize him in one sentence, I would say is his main mission, at least in his books, has been to talk about the amount of human variation that is possible. And I specifically referenced how most of us have five lumbar vertebrae, but as I learned from your book, you know, some people actually can have a sixth one. And then, of course, I looked into other research after that, and yeah, the amount of human variation is immense. And going back to Paul Grilley, his website, has some amazing bone photos which I use in every teacher training, where I teach anatomy on, and I still go back to, to this day. so, you know, those bone photos, there are some pelvises, there's some femurs. Did he take those photos himself?

Bernie Clark:

Um, his website is paulgrilley.com

Matthew Huy:

Okay, brilliant.

Bernie Clark:

he does have the bone library there. Some of the photos he's taken himself, some he had a professional photographer, Joe Dully, I think was the name. So Paul would go around to, uh, there's stores where you can buy fossils and bones, and he would always be looking at these bone stores, and one day he held up two femurs that had different angles of inclination, and he thought, well, wait a minute, there's no way this person could do what this person can do. And ever since he had that realization, he started to collect his own bones, but also he's gone to universities and looked in their bone libraries and taken these photos. He's very graciously made all these photos available. He says, download them if you want, make Christmas cards, send them to your students. So he's been very generous with sharing these variations that he's documented over the years.

Matthew Huy:

Yeah, I've definitely made use of them. Not, not for Christmas cards as such. Um, that's, yeah, that'd be a new one. and I like how you say that there are, stores you can go to, like fossil stores, bone stores, I don't know what things are like in Canada, but I've never come across a fossil store, personally.

Bernie Clark:

Oh no, well, Paul used to travel, he doesn't teach so much anymore. He's more into the philosophy side now he's talking about. Where he teaches the Yoga Sutra and the Gita. But when he used to travel, he'd have a bag of bones with him. And he said it was very difficult to get across the border into different countries. Because you're carrying parts of dead people. And he always had to talk to the customs agents about why he was bringing dead bodies into their war, into their

Matthew Huy:

Yeah, I can imagine. So I live in the UK and I took the Eurostar from London to Paris one time to teach on a teacher training there. And I brought my full size skeletons crammed into, into a suitcase and, um, yeah, I got stopped too. And I, as soon as they opened it, they could see it was a plastic skeleton, but, but nonetheless, I got stopped. Yeah,

Bernie Clark:

Yeah.

Matthew Huy:

which is funny. And which now, because of your work, thank you. Um, I, you know, I, whenever I pull out my skeleton, I always say, remember now, this is the average. And so we like to think we all look like this, but actually none of you will look like this. And if, if, you look at the average, then only 2 percent of the population is the average, actually. And in fact, you know, our, our skeleton will be like a fingerprint to us. So even if that's the average skeleton, actually no one in that room will look like that skeleton in that everyone's head of their femur will look a little different. The, the socket or the acetabulum where it fits into the pelvis will be. positioned a little bit differently. So could you tell us a little bit how you mentioned about the biceps, about other human variations that are possible and how that might affect someone's yoga practice or just their movement practice or their body in general?

Bernie Clark:

Yeah. I mean, the whole body is unique. We've got two, 212 bones or 206 bones. It depends how you count them

Matthew Huy:

Mm hmm.

Bernie Clark:

on some people. Some people have more bones. Some people have a second kneecap in the back of their knee. You know, the studies are quite fascinating. One study showed that 40 percent of people have a second kneecap in the back of their knee, and that's But it's small. It's called a fabella, which means in Italian, a small bean. But some people we know in yoga can't sit on their heels comfortably. There's just something stopping them. Well, it may be that they've got this second kneecap in the back of the knee that just prevents full flexion of the knee. And they never knew this, because they've got this extra sesamoid bone sitting right there in the back of the knee. Now there's one study that said 40 percent of the population has it, another study said 5%, so studies you have to take with many grains of salt, because they're only looking at maybe 10, 20, corpses or skeletons, so they're not looking at thousands and thousands, so when you have one study that says 4 percent of the population is like this, another that says 40 percent is like this, I kind of took the average and said, okay, about one in four people may have a second kneecap in the back of their knee and they might find it difficult to sit on their heels. So you can just name a body part and I can tell you how it varies and how that might affect your yoga practice.

Matthew Huy:

Yeah. And also the questions that we have as yogis, like, Why can't I bend my knee fully?

Bernie Clark:

Right,

Matthew Huy:

are not as, um, so, shall we say, urgent as in the medical world to look at, say, how to prevent dementia, you know? And so, so the, the cadavers are more likely to be used to look at the plaque on the brains of, of people who have had dementia, you know, versus answering the, the kind of quirky question of, you know, how much can you bend your knee and, and how much is that dependent on, on your kneecap? So, yeah, there's a lot that we don't know, but also it's, it's also understandable that we haven't looked into it that much through the research, because there are more pressing questions. But nonetheless. It is important for us to understand, I think, the variation that is possible, and that is thanks to your work. So again, thanks for your work.

Bernie Clark:

Well, this is something that medical med students hate because they want the one plastic skeleton that represents all the, all the, patients that we're going to have. But some people have a condition called situs invertus, where all the organs inside the abdominal cavity are flipped, they're reversed. So for these people, their appendix is not on the right side, it's on the left side. And if they come to an ER one day suffering some real sharp pains on the left side, the intern there may say, well, okay, that looks like appendicitis, but it's in the wrong place. Just go home and take some painkillers. And then overnight, the appendix bursts because they were looking on the wrong side. And sometimes the appendix is on the right side, but it's higher up. Or it's really low down and might be confused with an ovarian problem. So, even from a medical student's point of view, you have to realize the difference in every body. Because their textbooks, their anatomy books, are again, like your skeleton, they're averages of dozens of cadavers, and nobody looks like that inside. So, for a surgeon, they have to be very careful that they don't pay attention to the anatomy books. They have to look at what is the anatomy of this particular person before before they start cutting open and try to find that appendix. Where is it?

Matthew Huy:

absolutely. A good friend of mine is a nurse, and she's sometimes in the anatomy lab, and she said she remembers one person didn't have Two kidneys, but one monokidney, which was joined together like a U at the back. Yeah. exactly. So, yeah, yet another variation that's possible. So, it is great to know that, you know, we have all these variations, but how does that translate to yoga? How would you say?

Bernie Clark:

Well, unfortunately, around the 1980s, 1990s, when yoga started to get very popular, there was a big demand for yoga teachers. Now in the past, the only way you became a yoga teacher was you sat at the foot of a teacher for many, many years. You'd go to their yoga class, and after maybe 10 years of taking the class, the teacher had to go away for a weekend or something and said, Well, you're going to teach. And so you'd slowly be brought up as a teacher by that person on a very close one to one relationship over time. But in the 80s and 90s, when yoga started to get more popular, we started to mass manufacture teachers. And that was the birth of the 200 hour teacher training. And there we decided to cookie cutter the shapes. So we know you're a good teacher if you can put everybody into warrior two and have the knee pointing over the second toe, not the third toe, it's got to be over the second toe, and the back foot has to be turned in exactly 75 degrees. So we came up with this aesthetic approach to yoga, trying to make everyone look identical. And if you can do that, You're deemed to be a good yoga teacher. Well, that completely ignored human variation. And while knee over the second toe may work for this person because of the way their hip socket is anteverted and the amount of femoral torsion and tibial torsion they have, it's not going to work for everybody else. It may work for most people, may work for 50 percent of the people, but what are you doing to the people that it doesn't work for? Well, you're now internally rotating the femur at the hip socket to get this aesthetic. We should be looking at what's the effect of the pose, what's the intention, why do we want people to be more your pose, Warrior Two, and then have them pay attention to the sensations that that pose is generating and see if they match the intention. That takes up much more, that's more work for a teacher to do. Because now, instead of getting everyone to look the same way in a class, you have to figure out what's going to work for everybody in that class. That's more like personalized medicine. It's one on one, instead of just getting everyone to look exactly the same, like dancers in a chorus line.

Matthew Huy:

hmm,

Bernie Clark:

So this makes yoga teaching much more challenging. It's, it's possible. We just have to change from an aesthetic approach to a functional approach to teaching yoga. A functional approach, it doesn't matter what people look like in a pose. Forget universal alignment. What's important is what that person's unique alignment should be, and for that you're going to have to experiment. You're going to have to have an intention for the pose and test to see if the student is actually getting what they want out of that pose,

Matthew Huy:

hmm, mm hmm, yeah. You say it's that makes the teaching harder. For me, personally, I found that It's made the teaching easier by not getting into the weeds about alignment. And what I do as a teacher now is, um, I really just kind of call out poses. And I, you know, I go around and offer alignment cues, especially if I feel someone can do something a little bit better. You know, if they could go a little bit deeper into that pose, if I know they can lift their leg a little bit higher in half moon pose, for example. I really just kind of let people crack on with it and get on with their practice and explore it in their own body. And I'm just there to guide them. And particularly if they say, you know, this doesn't agree with me, or I see someone's dropped out for some reason, I like to give that person a little bit of extra attention. But for me, I find I just, Don't focus on alignment as much, having been a teacher who used to talk about alignment quite a lot. And, um, and I'm not worried that people are going to injure themselves, thanks to your work and everything that I've learned about and how our body adapts. You know, I know that their knee being over the third toe and not the second toe is not gonna, it's not gonna create an injury. They're not gonna leave there hobbling out because of my alignment cues. from my personal experience, that's one point that I would slightly disagree with, in a good way, that it's actually made my teaching easier.

Bernie Clark:

It can if you can make the mental adjustment, but a lot of people, and Paul Grilley points out, when they go through this change from aesthetic Yoga to Functional Yoga, they kind of go through the five stages of grieving.

Matthew Huy:

hmm.

Bernie Clark:

they just say, that, that can't be right. It's just arguing, uh, they won't accept it. And then they'll get angry because I just spent 3, 000 in a teacher training that taught me how to get these alignment cues all racked up here. And then they'll enter a bargaining phase. Yeah, but what about in this case, what about it for this? And they'll try to work around it. And then they'll go through a depression stage. Well, now I don't know what to say. And then hopefully they'll integrate it all the fifth stage. They'll absorb it all and go to the next stage of teaching. But it's not unusual for people to go through these, these stages when they're first introduced to a functional approach to teaching

Matthew Huy:

Mm hmm.

Bernie Clark:

I think once you adapt the functional approach, you're right, Matthew, that it can actually be easier because you don't have to memorize a thousand alignment cues.

Matthew Huy:

Mm hmm.

Bernie Clark:

Where should the middle finger be pointing? I don't know. I don't care. What are you feeling on the inside? I like to say you're giving flying lessons. Each student is in the airplane, and there's a difference between a Cessna 150 and a Boeing 747. Everybody's plane is different, and I can't tell them how to fly every plane, but I can help them learn about their own plane., I want to give the responsibility to the student to figure out how to manage their airplane. So I'm just giving flying lessons. I don't ever tell them what to do, because I don't know their plane. They're the ones up there. I'm just ground control. They have to take full responsibility for landing that plane.

Matthew Huy:

Yeah. That's why I often like to think of myself as a yoga guide. Rather than a yoga teacher, uh, I feel like I'm there just to guide people and let them have their own experience, really. I've even heard the, the term yoga sharer. That might be a little bit too extreme. I'm not ready to call myself a yoga sharer. But that's one of the reasons I don't like to say even, my students, because that suggests a power dynamic that I am here to teach you something. Whereas, you know, I've been doing it for 20 years now, and I'm pretty good at yoga teaching, but I, I'm really just seeing myself more as a guide and so I, I call them my clients because I am there to serve them. I think there are many great philosophies to be taught within the yoga classroom. I do think it is important that we see ourselves as serving the people that we are working with. As in helping them achieve their best rather than trying to take the limelight and being the The center of attention. What do you think of that?

Bernie Clark:

Yeah, I know. I agree. I often think the students are not there for my benefit.

Matthew Huy:

Yeah,

Bernie Clark:

I'm there for their benefit. So, like, like a doctor or clinician or therapist, I'm not there to live their life. I'm not there to tell them how to live their life. I'm just there to help them. I'm ground control. I may know more about them in particular areas, but I don't know what their life is like. I remember a woman came up to me, she'd been coming to my yin yoga classes on Sunday nights for a year. And I didn't really know her, but I recognized her. She'd, she'd be there. And after a year, she came up and gave me a big hug. And there was a little bit of a tear in her eye. And she said, you know, when I first started coming here, I had such bad back pain. I could barely get out of bed in the morning. And now after a year of your yin yoga classes, I'm completely pain free. So I thought, oh, that was a wonderful story. We hugged and she walked away. But as she walked away, I had to remind myself, I have no idea what cured that woman.

Matthew Huy:

Yep.

Bernie Clark:

I don't know if it was the yin poses, or maybe it was shavasana at the end of the yin. Or maybe it was just the calmness, the mindfulness during the practice. Or maybe it was getting out of the house, away from her husband once a week. Or maybe it was just being in a community of other people. I have no idea what cured her. But she was cured and maybe she would have been cured anyway if she just stayed at home or played bridge with friends. She felt like this was really of value to her. So that's great. That was her journey. And if I can help that in some way, but I just can't let my ego take over and say I cured this woman's back pain.

Matthew Huy:

Mm hmm.

Bernie Clark:

have no idea what cured her. All I know is She's pain free now and she's happy and great.

Matthew Huy:

And it's great that you got to be there on that journey

Bernie Clark:

Yeah.

Matthew Huy:

to see her experience from going from that disabling back pain to living her life better. And that shows that you're a critical thinker, Bernie, you know, that you can decipher, like, you can celebrate someone being out of pain. That's something definitely to be celebrated, but to know that we don't always know the cause of something. And this is an example I give in our book where we talk about critical thinking Imagine someone says, I ate a banana and my knee pain went away. Most of us would say, okay, that's correlation, not causation, right? But then what if I said, I went to yoga class and my knee pain went away? We like to draw the causation better, right? But we should take the same critical thinking approach that we would if someone ate a banana and their knee pain went away. Which is to say, it could just be, as it's called, natural history, which is the progression of pain as it goes away, like for example, 95 percent of lower back pain goes away within six weeks. That's the natural history of back pain. So, if you say, Someone started my yoga and their back pain went away within six weeks. Well, it's more like that was just the natural history. So, I think it's great that you, again, celebrated that woman's recovery and then also appreciated that maybe it was something else. Yeah, there are lots of elements going into that. So, I think that feeds really well into this idea of Yoga therapy. And for anyone that doesn't know, yoga therapy is this idea of using yoga almost like a doctor or a therapist to relieve certain symptoms or disorders. Like someone comes to you with, say, depression. So you, you focus on specific poses that are meant to alleviate depression. At least that's, that's the idea. The traditional approach of yoga therapy. And so can I get your opinion on this idea of yoga therapy and using certain poses to treat certain things?

Bernie Clark:

Yeah. Um, I guess this whole using yoga as therapy was, uh, an advent of the early 1900s. as the East and the West met in South Asia, the, the Western views of science and changes in medicine were Being brought to India through the British Raj, and of course within South Asia, there was the whole yogic world coming up. And there was a case being made for the traditional practices of South Asia to meet with modernity. so it was in the 1920s, 1930s that some particular yoga teachers who were very accomplished in the yoga practice, but were also scientists, started to come up with clinics who would marry these two together. So it was the natural cure, the health cure, going to the spa and all this. This was taking over all the Western world anyway, but from the South Asia perspective, they could bring some of these yogic and Ayurvedic influences to bear on as well. So they started to offer yoga, not as a spiritual practice. but as part of the health care. And so we got these studies showing that yoga can reduce blood pressure, yoga can help with asthma, yoga can help with all these different conditions. And we had the first scientific experiments, and we can call them scientific for their time. Today, they wouldn't be considered very good experiments because they didn't, they weren't double blind controlled random experiments. But for the time, a hundred years ago, they were pretty revolutionary. So that was kind of the birth of using yoga as therapy. Prior to that, yoga was still just a spiritual practice and Ayurveda was the life sciences and all that. But that continued to manifest throughout the 1950s and 60s. There was more and more studies done. And then Mr. Yengar kind of made this much more into the popular domain with his book, Light on Yoga. He specified these poses will help these conditions.

Matthew Huy:

Mm hmm.

Bernie Clark:

Now, I, when I was first learning yoga, I took that as gospel. I didn't know any better. I just thought, well, he must have done a whole bunch of experiments, whatever. And It wasn't until much later in my scholarship I realized these were just anecdotal claims that he was making, there was no scientific evidence for it. But if you've got eye issues or something like that, then certain types of inversions might help. If you've got asthma issues, certain types of pranayama might help. You can kind of see the logic behind making these correlations, but there is no strong scientific evidence for it. Now, we start to fast forward in the 1990s, 2000s. There, now, when Iyengar and others brought yoga to the West, And I think it was an export from India and yoga was packaged up for export to the West. Then the Western scientists started to get involved. There was a whole thing with, um, um, his name escapes me, Dean, Dean Ornish, who was a yoga teacher, a meditation teacher, but also a cardiac surgeon. And he started to notice that when he gave yoga exercises to his wife, Patients after a heart transplant or after a bypass, they recovered much more quickly than the people he didn't go to. So he actually did blinded control experiments. And then he found that if, actually, if we don't do the heart experiment or the heart surgery and we just give them the exercises, they also recover. So now we're starting to have Western scientists doing more rigorous Western studies on the effects of some parts of yoga.

Matthew Huy:

Mm-Hmm

Bernie Clark:

We have to be careful of some of the claims in the older books, like in the Hatha Yoga Pratipika, Hatha Yoga Pratipika. It says Padmasana will cure all disease.

Matthew Huy:

mm-Hmm.

Bernie Clark:

No, I don't think that was ever studied. I think there was no truth in advertising back in the 13 1400s. So people were competing for followers. So they'd make these outrageous claims. But today we do know yoga can be good for certain things. And we've kind of isolated, we've taken away the spiritual part of it, and just gone to the kriyas, the cleanses, the pranayama, and the asana practice, and find when we do assign these to a certain coterie of patients, they improve compared to the control group. So definitely yoga has been proved to be therapeutic. But not in all cases. It's not, uh, Padmasana will cure all disease. In my view, Padmasana destroys many knees, but it's going to cure disease.

Matthew Huy:

Yeah. I remember. I think you have an article titled that, don't you? PMA Destroyer, please. Quite tongue in cheek,

Bernie Clark:

I speak from personal experience, however. I tore both my meniscus

Matthew Huy:

Oh,

Bernie Clark:

early in my yoga career.

Matthew Huy:

Right. Yeah, if you force it, if you think, I must get into this position, because this is the position of enlightenment, right?

Bernie Clark:

And all meditators, you know, when I was into Zen, they all sat in lotus. And they said, you know, some pain is expected for Westerners, so no pain, no gain. So I stayed in Lotus, and I stayed in Lotus, and the pain started to burn in my inner knees, but I stayed there, and when I came out, the pain didn't stop. It took me two or three years to finally Get the arthroscopic surgery to fix it.

Matthew Huy:

Right. Okay. Yeah. And you think we were just talking about causality versus correlation, but you think that the cause there did was the forcing yourself into Padmasana.

Bernie Clark:

Yeah, it's pretty clear that the pain was telling me to get out and I didn't.

Matthew Huy:

Yeah.

Bernie Clark:

stayed there for a couple of minutes because, you know, again, Zen meditators will sit in meditation for 45 minutes.

Matthew Huy:

Yeah.

Bernie Clark:

I'd read all these books saying, you know, pain as usual for western hips. I hadn't met Paul Grilly. I didn't realize my hips were never going to change. I was just putting the torque into the knee.

Matthew Huy:

Yeah. Yeah, exactly. Oh, maybe they did have the potential to change, but not that quickly, right? Because, as you know, change is the butter quite

Bernie Clark:

hip socket, yoga is not going to change the anteversion of your

Matthew Huy:

Yes. Yeah. Yeah, so yeah, you're talking about the, the, where the, the, the socket of the pelvis points to for the femur. Yeah, exactly. No, that won't change. Absolutely. Right. Yeah. In, in a teacher training, after I, after I show the Paul Greeley photos, people then say, well, how do we know the difference? How do I know, um, You know, if this is something that can change, potentially, versus something that cannot. And that's when I point to you, Bernie, I say, Oh, Bernie Clark's books go into, he has this whole section on what's stopping me, right? And so you talk about the different types of sensation that you feel in an asana, like the tension versus compression, um, feeling. Would you mind just talking about that briefly?

Bernie Clark:

Yeah, again, I have to give credit to Paul for this. But I discovered it's not really binary. Tension and compression sound more binary. It's a spectrum. And tension, tension is a resistance of tissues to being elongated. Now you can think of a rubber band. You can stretch it fairly easily. So it's what we call compliant. But imagine a very stiff spring. It's hard to stretch it. It's stiff. Both materials are elastic, so you can think of your ligament as being like a spring, and your muscles like an elastic band. The muscles being more compliant, they can stretch easier. And so often when we go into a pose, what's stretching, what's elongating, is the muscle. But that's only one place where tension may arise. Tension also arises in the tendon, which is connected to the muscle. The muscle actually becomes a tendon. And the tendon is more stiffer than the muscle. But it too puts some tensile resistance in there. Then over top of that you might have some ligaments and then joint capsules and other fascial tissues like aponeurosis. All these are resisting elongation to varying degrees. So part of this answer to what stops me question is the type of tissue you're dealing with. And even then, why is the muscle stiff or compliant? It may be a neurological input. www. ottobock. com It may be that something called a Golgi Tendon Organ is telling the muscle to relax, or it could be some stretch receptors inside the muscle itself, muscle spindles, that are telling the muscle to tighten up. We all have a certain degree of tone in the muscle. Some people are hypertonic, and they get contracture and other things where they just can't relax, they can't even straighten their fingers because they're hypertonic. Some people are hypotonic, they're super loose. And they have no problem flopping over and touching their toes because their hamstring muscles are just so relaxed. So it may be the nervous system. It may be the immune system. When we have a cold or something, we feel stiff and achy. Because the immune system is secreting a chemical cytokine, a messenger, called TGF beta 1. And we have cells living in our fascia called myofibroblasts, that when they sense the presence of TGF beta 1, they contract. And so it's like Mother Nature is designing us to slow down when we're sick, so that we can spend more energy in the immune system. So there's lots of reasons why the muscles might be tight. It's not just that they're physically short or long, It could be neurological, it could be immune system, it could be hormonal. We know that women at certain periods of their hormonal cycle, their fascia is much laxer than at other moments. Which is why we now think that women are four times more likely to tear their ACLs than men. Female athletes during their period are four times more likely to tear their ACLs than when they're not during their period because of the relaxin and estrogen and the chemical reaction of the fascia to these hormones. So there's lots of answers to what's causing tension. But once you work through that tension, eventually the body is going to come into contact with the body and we reach a point of compression. Simple example is if you extend your arm out, at some point the arm is kind of straight and you can't go any further. If that was tension, you'd feel it in the biceps. If the biceps are short and tight, you just can't straighten the arm enough. But once you work through that tension in the bicep, eventually, The ulna and the olecranon process of the ulna is going to hit the distal end of the humerus called the olecranon fossa. When those two bones come into contact, you've reached the ultimate point of compression. No amount of yoga is going to change that. Now it turns out my right arm, I can't quite straighten it.

Matthew Huy:

Oh yeah,

Bernie Clark:

I can get to 175 degrees because my olecranon process is just a bit thicker than normal. The bones are hitting, but I can't straighten it. And for many students, they go past 180 degrees. And they're still stopped with bone hitting bone. But yoga teachers freak out when they see that. They say, you're hyperextending. Don't do that. Well, they're just going to where the bones stop and that's healthy for the bones. So I'm not afraid of hyperextension if it's caused by a bone on bone compression. I might be afraid of hyperextension if it's caused by an injury or a genetic difference like Ehler Danlos disease, where the joint capsule is very lax and is not preventing the bones from going past where they normally lock. So, but anyway, on the spectrum, you're either stopped by tension or compression. And if it's tension and you know how to determine that, then you can keep going. Over time, yoga is going to stretch out those stiffer tissues. But once you get to the point where the body is hitting the body, you've reached the limit of how far you can go. And there's no point trying to go further. Now with my hips, I had reached the point of compression, but I wasn't paying attention to those signals. So I thought I can keep going further. Instead, the pressure went to the next joint down the chain, which was my knee. So I was just putting more stress on my knee because I was ignorant about what was stopping me in my hips until I met Paul.

Matthew Huy:

Right, yeah. And that could be a tough pill to swallow, to tell someone, you know, you know what mate, it might be your hips, and you might never get into full lotus. That could be a tough message to deliver to someone, it could be a tough one to receive also, but the reality is, yeah, it's possible that not everyone will be able to do everything in this lifetime,

Bernie Clark:

right. Um, think of squats. A lot of people can not get their heels to the floor in the squat. And yet they think it's something that's wrong with them. They're just not doing the pose right. They're not, they don't have enough ujjayi breath, too much mula bandha. And yet it's just when the front of the shin, the tibia, hits the top of the talus bone, the first bone of the top of the foot. When those two bones hit, you cannot dorsiflex your foot for it any further. If it was tension, you'd feel it in the calf muscle, in the Achilles tendon. But once you've gone through all that stretching, when these two front bones hit, that's it for how much you can dorsiflex your foot. And that may mean your heels are never on the ground in down dog or in squat pose. And that's okay. Maybe in your next lifetime, you'll have different shaped talus bones. But knowing that that's the limit of what your body can give you. It actually frees you up to not keep trying to go further. And that's when the injuries happen,

Matthew Huy:

And that's how I conclude that session after I show some bone photos from Paul Grilley is to say, you know, maybe the reason you cannot do side splits is not because, you know, you haven't purified your soul and your hips aren't open, but rather maybe just, you know, you got bones that are built in such a way that they don't allow that full abduction of the hips, you know, and that's okay. And people always feel relief thinking, okay, yeah, maybe that's just the way I was born.

Bernie Clark:

Yeah. I had one student who was, uh, an ex ballerina and she quit ballet in her late teens, and when she discovered that she couldn't dorsiflex her foot enough, and she didn't have a great deal of external rotation, she started crying because she realized that all the time that she was being criticized as a ballet dancer, she thought there was something wrong with her. That she just wasn't following the instructions right. And when I showed her, no, you're never going to get to the grand plie, the second position or whatever it is because you just don't have the bones for it.

Matthew Huy:

Yeah.

Bernie Clark:

And that was such a, a forgiveness for her.

Matthew Huy:

Yeah, exactly. Exactly. And you can start to accept your body. Yeah.

Bernie Clark:

Yeah.

Matthew Huy:

Bernie, you've, you've mentioned fascia a couple of times, that great big buzzword.

Bernie Clark:

Yes.

Matthew Huy:

so you and I have had a little bit of, uh, should we say disagreement on this at one point online. So in our book, uh, specifically in the chapter that I wrote about the musculoskeletal system, I said, Yin Yoga cannot target fascia. And all I was saying was basically. Whether you are doing a long held pose in a vinyasa class or a yin class is that the, the effect on the body and the tissues will be the same. And knowing what we know about muscle extensibility

Bernie Clark:

Right.

Matthew Huy:

is that it's probably more down to the nervous system than actual connective tissue. So. It's not really clear, uh, that yin can target fascia, was my point, and also, what even does that mean, to target the fascia? I think you are more specific in, in that you talk about applying a stress to connective tissue, and as a result, our body Our connective tissue gets stronger through that stress, right? But, anyway, and then one last thing, I remember on a blog post you said, the authors seem to not understand about the longer time held on a stretch or something like that. So, let's get into the weeds about this. What's our disagreement on fascia, Bernie?

Bernie Clark:

Well, first of all, let's clarify two terms. There's targeting and there's isolating.

Matthew Huy:

Mm

Bernie Clark:

heard this from other yoga teachers as well. They take issue with yin yoga teachers who say that we target the fascia and then they mishear what we meant by target, and they think we said isolate. We're not saying that we can isolate the fascia and only affect the fascia. So I mean, let's take a simple pose, like straddle. Straddle is like Upavishta Kanasana. It's a wide legged, seated forward fold, but with no muscular engagement. So there I could be targeting the fascia along the inner legs. And of course there's the adductor muscles there too. So when I have my legs apart and I'm folding forward, I'm affecting the adductor muscles. It's like if I went to a gym and I wanted to work on building big biceps, I would get some kettlebells and I'll do curls. I can say I'm targeting my biceps. But that doesn't mean that I'm only affecting the biceps. The deltoids work, the pectoralis works, the big back muscles are also working. I'm not isolating only to the biceps. I'm affecting the whole system. Even my heart, my blood pressure, all that's being affected. But my intention was to work the bicep. So my intention in this yin pose is to work the fascia. Along the way, I'm also going to put a stress into the muscles and to the bones and to the nerves and to the blood vessels. All those things will be affected. So I'm not isolating the fascia, I'm targeting the fascia. Now, the reason we want to target the fascia in yin practice with long held holds is because there are certain physiological things that only happen over time. If you're in a vinyasa class and you hold the pose for five breaths, that doesn't give enough time for the tissues to relax. imagine a mesh stocking, they have crosses of fibers that form kind of a grid pattern. And if you were to pull that longer, the grid will kind of change direction. Instead of being squares, they'll become more like diamonds, and eventually all the fibers will line up. Well, that happens in fascia as well, but it'll take time for those tissues to reorient. And then also there's a thing called creep that happens. Like, imagine if you put a blob of silly putty on the wall. You tack it there, come back in an hour, and it will get much longer. It'll creep. So it takes time. This elongation over time, the amount of elongation is called strain, that's a function called creep. And tissues being viscoelastic, when you first put a stress into it, it just deforms very quickly to its limit, and then stops. It's stuck. So it's viscous. If you slow that down, then eventually it starts to creep. And so in yin yoga, what we're doing is we're giving time for the tissues to, first of all, release their internal tension. And a study by Carla Stecco, who's a fascia researcher in the University of Pavia in Italy, she calc She said it takes about four minutes for full relaxation to occur inside these fascial tissues. And then the creep can restart. So it takes at least four minutes before you've just done all the reorientation of the fascial fibers, and then the cross links as well start to release. So that's the internal releasing, and now the actual Collagen bundles can actually start to elongate. That's when the creep turns in. So this doesn't happen in a short vinyasa hold pose. There it's most more the muscles are kind of reorienting because they're painated as well. It just means they're at an angle and they may start to change. That's only happening the first 30 seconds or so. If you want to get into the fascia, which is much more stiff, it's going to take a longer stress before you'll start to get those effects. That's one thing. The other is the state of water, which we also talk about later, but

Matthew Huy:

So, and you said, or you say in complete guide to yin yoga. And by the way, can I just say also I appreciate that, A book is a snapshot of what we understand at that time. And so there, there are things in my book, even, that I've, I've learned from and changed my views on. So, so I appreciate if maybe you've changed your views since you've written this, but you, you also talk about how, when we relax the muscles, right, versus engaging the muscles, that we can get into these, as you call, yin tissues, more like the fascia and the connective tissue. But. Would it not be the case, do you not agree that by engaging those muscles that actually that would apply more stress on the connective tissue and so they might respond more favorably and become even stronger because as we know through adaptation, you know, tissues adapt to the demands placed on them. And that's that's the point of doing a stretch. There's even a term known as stretch mediated hypertrophy, or the idea that we can actually build muscle through stretching alone. You have to do a heck of a lot of stretching to get there, but the point is, yes, we do know that tension on a structure or stretching can increase the strength of that structure, of that tissue, right? So anyway, so what about that? Does a muscle need to be engaged or not engaged? At least, what's your take on it?

Bernie Clark:

Yes. No, maybe. It depends. I'm not sure which edition of the Complete Guide to Yin Yoga you have, Matthew, but in the second edition, okay, that's the first edition.

Matthew Huy:

First edition. Yeah,

Bernie Clark:

2012. I did a second edition just a couple of years ago where I, I dive into this in a bit more detail because as you say, these are snapshots in time. We continue to learn and I think, oh, I wish I

Matthew Huy:

Mm hmm. Yeah, exactly.

Bernie Clark:

When the muscle is engaged, it will put more stress into the tissues that are serially aligned with the muscle. So, the tendon is serially aligned with the muscle. And I did a very expensive experiment to prove this. I took two elastic bands, one very thick and stiff, and one very thin. And I tied them together. And when I stretched them both out, The very thin one stretched much more than the thick one. So the thick one represents the tendon. The thin one represents the muscle. Now imagine if the muscle was cold, or contracted. Then it wouldn't be so stretchy. So I did a second experiment, but with a slightly thicker second elastic band. Tied them together, stretched them out. And sure enough, this time, the thick, the thickest elastic band stretched more. So it is true that the stiffer the muscle is, the colder the muscle is, the more engaged the muscle is, more tension will go into the serial tissues. Well, the serial tissue is the tendon, but there's also parallel tissues, such as the joint capsule. The joint capsule is in parallel to the muscle tendon union. So if my intention is to target the joint capsule, I want the muscle to be as relaxed as possible. If I want to target the tendon, I want the muscle to be as cold as possible. Now, ligaments can be both in series or in parallel, depending on which ligament you're talking about. So, depending on which tissue I want to target, there's times when you should do your Yin practice when the muscles are cold. But if you want to target some other tissues, there's times when you should do it when the muscles are warm. if you want to target the joint capsule, do it when the muscles are warm. Because the muscles are in parallel to the joint capsule. If the muscles were very stiff, Then you put a stress into it. Maybe no stress is going in to the joint capsule. A good example is to take your forefinger, tighten it really tight and try to pull the finger away from the hand. It won't move. The muscles are taking all the stress away. But if you relax that forefinger, the muscles really relaxed. And now you can feel this is going into the joint. You can feel how I'm distending the joint capsule. Well, this is an example of in series here. If you want to, if the muscles are engaged, the muscles are cold, the stresses aren't going into the joint. If the muscles are warmed up and very loose, now I can put the stresses into the joint capsule. So you're right. There are times when you do want to do the practice when you're loose and warm and relaxed. That's going to work more of the joint capsule. But ligaments and tendons are in series with the muscles. If I want to affect those tissues, I want to do it when the muscles are colder, because the colder muscles will actually put more stress into the other tissues lined up in series with them.

Matthew Huy:

Now, would you agree that a lot of that is based on supposition and, being guided from good first principles, but at least to some degree based on some speculation?

Bernie Clark:

Well, I don't know of anyone who's tested the actual force manipulators, the stresses in the tissues here. So the best I could do is simulate this with three different elastic bands. One really stiff elastic band that represents the tendon or the ligament, the tissues in series, and then a loose elastic band for warm muscles. and a stiffer elastic band for cold muscles. And when you tie them in series and you put a force into them, you'll find when you've got a cold or thick elastic band in series with the tendon, more of the stress will go into the tendon as observed by how much elongation or strain it exhibits. If I put a loose elastic band in there and stretch it to the same amount, you don't get the same amount of strain. So it's a simulation of what must be going on in the tissues. But, yeah, I have no actual evidence of what's going on in the tissues for or against this, this hypothesis.

Matthew Huy:

Yeah. And someone we both know, Jules Mitchell, is kind of the expert on tissue mechanics, so I'm going to invite her on and get her take on it also. But nonetheless, we surely can, in various positions, whether we're cold or not, we can certainly put stress on certain tissues of the body. Like, we can stress our ligaments, right? Okay. So then the question is, Is that a good thing? especially for holding it for five minutes. Is that a good thing? Why is that, why is that a good thing, Bernie?

Bernie Clark:

you just said before, because of SAID, Specific Adaptation to Imposed Demand, our body is designed to improve by being stressed. Now, a lot of people react negatively when I use the word stress. So, if you don't like the word stress, think of load.

Matthew Huy:

Mm hmm.

Bernie Clark:

or exercise or tension, whatever synonym you want to use for it. But stress is not bad per se. If it's, if there's too much stress, we enter a state called distress and that's bad. But a healthy amount of stress, technically it's called eustress, that's where the body adapts. So all tissues, whether it's the immune system, the nervous system, the brain, the muscles, the fascia, all these systems need stress to stay healthy and to become stronger. So the fascia is no different. Now then, what is the optimal way to stress these tissues? Well, as I talked about before, fascia being viscoelastic, it doesn't really release all its internal resistance until you've held the stress for four minutes. And that's an average. Depends on which tissue and when and how warm you are and so forth. So we do need to stress these tissues longer. If I was to say to you distraction, um, or traction, in the medical community, people know about traction. If somebody's got a joint issue, they might put them on a bed where they separate the beds apart, like an old fashioned medieval rack. They'll put them under traction. They don't just stay there for two minutes, they stay there for hours. So we know in the medical world that traction, it can be very healthy for rehabilitating certain tissues. So what we're doing is we're just applying this traction in a yoga world. do this all the time, by the way, when you sit, like we're sitting and talking, our lower back is flexed and we're like this for an hour. So we do yin yoga all the time. We just don't call it that. When you're sitting at your desk for eight hours a day, when you're driving your car, when you're sitting at breakfast, or if you're a weeder standing on your foot all day, you're putting a yin stress to the bottom of your feet. There's so many times we're holding poses for long, long periods of time, and we don't freak out about it. But now we come to a yoga room and I'm putting you into a wide leg forward fold for five minutes, people are saying, oh, is that a good idea? Wait a minute, you just took half an hour to drive here and your body was in one position for that. Or you flew in an airplane for 12 hours and your body was in one position. You weren't freaking out about that. So why are you freaking about five minutes of just long held static stress? We do it all the time.

Matthew Huy:

How about the long held static stress through your menisci, which are cartilage, semi lunar shaped cartilage in the knee. You applied a stress on them when you were trying to do full lotus, but that was too much for your menisci, as you told us earlier. So, mm hmm.

Bernie Clark:

There was pain and the body is pretty good It's not perfect, but the body is pretty good at telling you when to stop And this is early in my career, I wasn't paying attention to my body. I was feeling the distress, I was feeling the pain, but I ignored it. So a big part of yin yoga is teaching people to pay attention. If I go back to this flying your airplane analogy, I'm trying to teach you to read the cockpit. And there's a little engine light there that's flickering on and off. It's red, flashing. Don't ignore that. I was ignoring my engine light. I should have been paying attention. Instead, I stayed there and I broke myself.

Matthew Huy:

Yeah,

Bernie Clark:

Cartilage needs stress. Cartilage needs to get stressed, but you don't want to hold that stress so much that it's burning pain. That's just stupid to do that. I was stupid to do that. It was the Black Knight Inc. And Monty Python's Search for the Holy Grail, you know, the arm comes off, he's a flesh wound.

Matthew Huy:

love that sketch, yeah. Pain has been described sometimes as a smoke alarm. So, it's just there to let you know that something's wrong, but it's not specific. It's not saying this here, right? And it's not saying the level, it's just saying, hey

Bernie Clark:

In this case, it was very specific. My inner knee was

Matthew Huy:

be specific, but I don't, it's, it's not as specific as saying, you know, like, this is your tendon versus your, your muscle, for example, um, and sometimes we're going to just have a dull ache in, in the back and, you know, so it's not specific about whether that's a bone thing, you know, a tumor on the spine or something, just like, you know, you sat too long at your desk this week. Um, so yeah, it's a bit like an alarm bell. So it's, it's one of the things to be considered when,

Bernie Clark:

Yeah, pain

Matthew Huy:

along with all the other factors. Mm hmm.

Bernie Clark:

we're learning more and more about how pain arises and how it perpetuates and so forth. But generally, I'll warn my students, when you come into the pose, If you feel anything sharp, burning, electrical, tingly, come out.

Matthew Huy:

hmm.

Bernie Clark:

like I was.

Matthew Huy:

Mm hmm.

Bernie Clark:

that something's not right. Back off. Now, it may be inappropriate, maybe you're backing off too early, but I don't have a better way of diagnosing this. I wish God had made LED lights on our forehead, you know, green, yellow, red, and when it's red, definitely get out. When it's yellow, be careful. But we don't have that. We've got this biopsychosocial event in our brain called pain. In the book, page 21 of Your Body, Your Yoga, there's a whole table I give of different places where tension and compression can arise, what sensations will be typically presented, and then what pain may arise. Now, this is not for everybody, because we're human variation. Some people feel these pains differently, but a pain in the bone has a very different signature than a pain in the tendon or a pain in the muscle. So if you start to pay attention, you start to teach the students their cockpit and what certain symbols and dials mean, they can start to become better aware of what the interception, the signals from the body itself, and what they mean.

Matthew Huy:

Mm hmm. So one last thing I'd like to ask you about, And, you know, respectfully, we're taking a little bit of issue.

Bernie Clark:

Yeah, yeah,

Matthew Huy:

The credit card analogy, Bernie, which I've had to, discuss in many teacher trainings. so, in your first edition of, The Complete Guide to Yin Yoga, and I don't have the second edition, so I apologize, but you know, you do compare the spine to a credit card, and you know, bending it forward and backwards, you know, might like a credit card snap in half, and then I know in Your Body, Your Yoga, you qualify that, and you know, you said, Just so you know, we're not really like credit cards. Those are basically made of PVC, right? And we are, you know, we are complex biological, organisms with collagen and lots of factors affect us. but you still did use that analogy. and for listeners that don't know, that analogy, or at least this, this idea of the spine being injured by repeated flexion extension comes from the 1990s. By some good biomechanical research by Stuart McGill and, and others like Jack Khan, I think the name is, uh, where they looked at, um, dead pig spines, put'em in flexion extension over repeated times. Something like 78,000 times over 24 hours. You know, some of them herniated, some of them didn't. Um, and so we, from the argument against. against, um, against kind of your analogy that you used, uh, is that we should not apply biomechanical learnings from the laboratory on dead pig spines into living humans. So anyway, I've said a lot. Now let me hear your take on the credit card as the spine is a credit card analogy. Mm

Bernie Clark:

Yeah, in, in Your Body, Your Yoga, there's a graph that I use, and it's also in the second edition of the Kavlika Adyen Yoga. This graph shows the effect of, uh, constant repetitive stress on the tolerance of a tissue. And usually, when tissues start out, they're fairly healthy, and if you put a stress on the tissue, it becomes slightly weaker. You repeat that stress, it gets weaker. Repeat it, and repeat it, and repeat it over and over again. At some point, these two curves will cross, and that's where an injury will occur. The tolerance of the tissues got weakened because of the repetitive stress. But the second part of this graphic shows the effect of rest. The refractory period. Unlike a credit card, which is inanimate, living organisms recover after stress, provided you give it enough rest time. And then the tissue we just used becomes more usable. The tallest level actually goes above where it was when it started. And now you can start to stress it again. So the whole theory of exercise is we need to stress tissues, then we need to rest tissues. So when I'm talking about the credit card effect, I'm only talking about one half of this equation. If you only ever stress the tissues, and never let them rest again, They will break. The tolerance of the tissue to further stress will be below the stress threshold, and that's where the injuries will occur. But through the miracle of refractory period, of Shavasana and other rest periods, you let the tissues recover, then they become stronger. So you're right. And I'm right. It depends on how much of the curve are you actually looking at. If you're only stressing, which is why a lot of fitness instructors will say, work your upper body today and tomorrow we're going to work the legs. So we can give the upper body a full 48 hours to recover. You're probably not going to work the upper body, uh, for an hour and then take a break and come back an hour later and work them again. Take a break, come back and work them again. You're going to have to leave a rest period for those tissues to recover. So that's the refractory period. Unfortunately, as a teacher, you probably have noticed there's a few students who hate Shavasana. They just think it's a waste of 10 minutes. They have other stuff they can do. So they leave the class. I don't want to do the Shavasana part, but that's the refractory period. If you don't have that to recover everything else, and you just go off and go for your run or whatever, you're not giving your body a chance to recover. In that case, the cumulative weakness will get worse and worse. So I agree that we're not credit cards, we're not inanimate objects, but some people treat the body that way. They don't give themselves enough recovery time. So we need that refractory period so that the tissues we just used becomes more usable.

Matthew Huy:

Yeah. And I can think of a, uh, client of mine who attends our online classes who's suffered with hamstring tendinopathy for a few years, and as he knows, it's just because he doesn't rest enough. He just keeps aggravating the same thing, you know, and, keeps exercising that, that same place. And it's not to say it's just yoga, it's yoga in combination with other things like kettlebells and stuff. But yeah, that is, that is day one of exercise. science degree is the idea of adaptation and the idea of, putting a stress on any tissue of the body, whether it's muscles, connective tissue, even your lungs, you know, or even your brain, and then that resting period, and we get stronger, that period of super compensation where we're actually stronger than we started. and then we can make these progressive gains get stronger and stronger. And that ideally, If you're trying to get stronger, you're timing it so that you are stressing your body at that point when you are at the strongest again, you know, and that's what the Olympic athlete coaches are trying to get to, right, to push that their athlete to right, just the right level. Where they're stressed, they recover, and then they stress again, recover. but yeah, okay, so, you like to use the analogy, but I like how you've qualified it here and changed it. Do you regret putting it in the book? Yeah,

Bernie Clark:

I regret

Matthew Huy:

that

Bernie Clark:

when I first did the book, I didn't do the second part well enough. I still believe that we can do a credit card effect to our spine. For some reason in yoga, we think that backbends are a sign of enlightenment or whatever. And if you can do drop back to wheel 108 times every morning, that's great. But I remember one of my early teachers, Eric Shiffman, saying he was doing that when he was in India, dropping back to wheel 108 times every morning. And one morning he woke up, he couldn't move. He'd almost broke his back. And Iyengar him, what were you doing? He said, well, I was doing this every day. He said, stop doing that. to do something every day over and over again, just putting that stress in there. Did almost break Eric's back. He wasn't letting it rest. So I'm not saying don't do these things. I'm just saying you have to allow the recovery period too. Or you will suffer the credit card effect. So I wish I'd qualified it a bit more.

Matthew Huy:

but not, not that your spine will snap enough, and I guess, you know, my master's. In exercise science, my, my dissertation for my master's was all about fear based language. And, and, you know, I, I, I did use your, your your language there as a reference.

Bernie Clark:

I

Matthew Huy:

and how actually that. can create,

Bernie Clark:

of nocebos. We don't want to

Matthew Huy:

yeah, yeah, yeah. And create fear, you know, fear based beliefs that come from, from the language. So I hope people don't have this fear that, their, their spine might actually snap,

Bernie Clark:

No, I wouldn't say the spine would ever snap.

Matthew Huy:

sense. Yeah.

Bernie Clark:

I can't visualize the spine actually breaking in two, but it's just some of the ligaments may get torn, a little, a little trauma there happening.

Matthew Huy:

Yeah. I'm glad to have been able to ask you that and, you know, hear it from the mouth of the horse as it were.

Bernie Clark:

Well, there's a saying in yoga that you can bring a horse to water, but you can't make him do triangle pose.

Matthew Huy:

Yeah, exactly. Oh, great. So, Bernie, what are you up to these days? I know you sometimes teach yin online, don't you?

Bernie Clark:

Yeah, I have a weekly online class every Sunday, and for those that can't make it because of Vancouver time, it's available in the replay, so you can either watch this week's replay or go to the archive of the last few years. And I'm also offering, uh, in yoga teacher trainings, uh, online and in person. So, the pandemic's over, we're back to in person classes as well.

Matthew Huy:

Mm hmm. Is your teacher training a hybrid where it happens in person and people can watch online also? Or are there

Bernie Clark:

the

Matthew Huy:

things?

Bernie Clark:

Yeah, two different things? The course is slightly different. I've actually had people in the room. We can do a few more hands on type stuff.

Matthew Huy:

Yeah. Brilliant.

Bernie Clark:

a year we have in person, twice a year we have online. And we also have an on demand that people can just take at their own leisure.

Matthew Huy:

Awesome. Great. And then, of course, you have all the amazing books that you've written. Your Body, Your Yoga, Your Spine, Your Yoga, Your Upper Body, Your Yoga, and then the Complete Guide to Yin Yoga. Bernie, I think your contribution Oh, sorry?

Bernie Clark:

yeah, there's also a couple of others. There's one called, Shiva Dancing at King Arthur's Court, which is a collection of mythologies, East and West, and explaining how, how can people who were raised in the West understand the symbolisms of the East? Like what does Shiva standing out of a dwarf named Mavigia mean to an accountant in Toronto? There's that's a book inspired a lot by the teachings and the works of Carl Jung and, uh, Joseph Campbell.

Matthew Huy:

Brilliant. Thank you. I can't thank you enough for your contribution to the yoga world, to what we know about anatomy. I always love dipping into books. So, thank you, Bernie. And thanks for taking the time to talk to me, too. you wrote in your email, I'm in my eighth decade, I like how you said that. You don't look it, you look amazing, so whatever you're doing, that yin yoga or whatever is definitely working.

Bernie Clark:

Yeah, yoga's great.

Matthew Huy:

Yeah,

Bernie Clark:

Highly recommend it.

Matthew Huy:

Me too. Thanks, Bernie. Thanks so much for, for being here. Really appreciate it. Thank you, honestly.

Bernie Clark:

Bye for now.

Matthew Huy:

Bye.

Saz:

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