Dr- Stephen Levin

My 20 Favorite Moments From Season One (Part 1)

6151476235_7200e501bd_zLast week I sat down to write a post on some of what I learned from season one of the podcast... and it turned into a 3 parter. Brevity just isn't my gift. Sometimes there's just too much goodness to condense it into a short article. So this week is part 2 of 3, where I begin getting into my favorite moments from some of the episodes. Initially started as a "top 5" list, it's now 20 items long. Oops. One through ten are this week, the final ten will be up next week. Here are some of my favorite mind-blowing moments; the things that have stayed with me and continue to dart around my brain and body on a daily basis: 1. We are built more like foams than like buildings. “Essentially we are foams” according to Dr. Stephen Levin. Whaaaaa!? Mind. Blown. This talk is, as one of the listener’s who wrote me said, a “braingasm”. So if you want to get friendly with biotensegrity and the miracle of the omnidirectional icosahedron (I just wanted to see how many syllables I could fit into two words) and how its shape is our most fundamental building block from the cellular level on up, give it a listen.

2. Every step I take is a conversation I’m having with the planet. “This relationship of gravity and this force that the opposite force is called ground reaction force or the secondary force of gravity.It actually literally pushes everything off the planet toward the stars. A lot of people know about these forces but it’s how you maximize and optimize the use of pushing off the ground and relaxing into it to be weighted... it’s a dynamic recycling of gravity and ground reaction.” Thank you Judith Aston, you have forever changed my walks through the woods (or anywhere for that matter).

3. That whole core stability altar we’ve all been worshipping at for years (myself included)? Yeah, turns out that’s a wild misinterpretation and misapplication of the data. Dr. Eyal Lederman: “Basically there are no sub-systems in the body. There’s not a sub-system called core muscles. We’d like to believe there are muscle chains and some kind of system of core, global, muscles, and so on, but it just doesn’t exist in human movement.”

4. We have to take our whole lifestyle into consideration when we train, or we are at risk of injuring our neuro-endocrine system, and (let me tell you from experience) that’s a slow one to heal. Dr. Steve Gangemi, “I’ve done enough Ironmans in the past where you’re just running your health down just that little bit to exceed that little bit extra. It’s okay if you do that for a competition but you’ve got to be careful about doing that too much, too often because the next thing you know you don’t recover well or you end up with some chronic injury that you just can’t resolve and you can’t figure out. Because it’s due to an actual physical depletion of vitamins, minerals, hormones in your body and not just a straight out structural shin splint, shoulder problem or whatever type injury. It’s not local. It’s becomes more systemic.”

5. “The study of anatomy does bring us into a much deeper understanding of ourselves if we’ll let it.” Hallelujah Gil Hedley, hallelujah! I asked Gil how he feels the model of the body that we’re functioning from is determining our behavior towards our body, and he replied: “The thing is that anatomy is generally understood as this naming of things based on the cutting up of them. It generates a very abstract set of information and categories. I literally mean abstract meaning the levels of tissue have been drawn away from other levels of tissue. Abstraho literally means to draw away from, so we draw one thing away from another, and then we develop a mental conception of it. Every time you approach a body with an idea, and then execute that idea with a knife, you’re making up anatomy, because there is no such thing as a liver on a tray. There is no such thing as a skin unto itself, except through a process of dissection, and abstraction. Those aren’t realities. The reality is this whole flesh and blood pulsing experience that we’re all wandering around with.

Then we get our abstraction built, and then we say, “Oh, okay. There’s this muscle, rectus femoris, there this muscle adductor magnus, there’s this thing in our chest, the heart, and that’s a pump. The other one abducts and the other one adducts. We have all of these very abstract, conceptions. Then we approach with our techniques people, and we see them move, and we have that set of abstractions in our brain, and we say, “Well.” It’s like a math problem, and we add it up, and say, “Well, this should be doing that because of what they’re doing there. Then we apply our abstraction to the form, and try and make it emulate what our abstractions tell us it should be instead of taking in a given whole set of compensations and helping it to function better.

The actual functional person is always a gestalt of all the systems, and all of the hopes and dreams, and all of the life processes, and all of the trillions of cells streaming. In other words, that’s what’s happening in front of you, not, “Oh, we’re having difficulty abducting our x, y, z. Which would be cured by strengthening the a, b, c.” I don’t think we work that way.

I don’t think I’ve fallen too far from the Rolfian [Rolfing] tree in my aspirations along with you to transform culture. She was looking to cultivate a more mature human being, and I feel that I’m wanting to do the same, at least for my part. I feel that part of that maturity lies in an acceptance and learning from the body.”

6. Support and stability are not the same thing! It’s support we need more of, and our grasping at creating stability isn’t helping us to find it. Mary Bond, “I’d like to make a distinction between support and stabilization. Support is something we receive. We allow ourselves to be supported. Lots of times, that’s a problem.We can’t, for some reason or another because of habituation. It makes it difficult for us to trust that we could allow ourselves to be supported by the ground or by another human, by the table. Support is something that we take in and allow.

Stabilization is something that we do. We stabilize the core in order to push off from the ground and lean into the air, for example. We need stabilization, but in this culture of hyper-fitness, there’s too much emphasis on stabilization. I think it’s because we lack support and people don’t see that. They don’t see that distinction.”

7. Tissue damage does not correlate particularly well with pain. Todd Hargrove: “Pain is an unpleasant conscious experience and it is designed to protect you against what the brain perceives as a threat to the body to motivate you to do something about it. Pain is an output of the brain- it is something the brain creates to warn you of the situation.

The reason I make that clear is that sometimes we get confused about pain and tissue damage. Tissue damage is damage in the body. It results in a sensory signal, a nociceptive signal coming from that damaged area. That’s not pain yet. The damage is just damage, and the signal is just a signal. It goes up into the brain and then the brain decides what to do about it. It’s not going to create pain unless it decides, ‘This is a dangerous situation, we need to create pain to protect us from that potentially dangerous situation.’ It might decide, ‘I hear those nociceptive signals, but I don’t want to create pain right now because I don’t think that’s a good idea.’ For example, if you were a soldier, and a toe got cut off, it would surely activate nociceptors in the foot and send a signal, but the brain might not create pain, because the pain might not promote your survival very well. The brain might think, ‘We’re not going to create pain because we need to run across this field and to get out of this emergency situation.’ That’s why people often don’t feel pain in emergency situations.

On the other hand, there might be a relatively innocuous situation going on in the foot, and there is sensory information coming into the brain, and the brain for some reason interprets it as a very dangerous situation for the foot, and so can feel a lot of pain even though there is not a lot of tissue damage. That might be why tissue damage doesn’t correlate all that well with pain. It’s because the important decisions are being made in the brain by the neuromatrix. The brain can be confused. Something happens in the body, the sensory organs report it, and it’s like a big game of telephone. The spinal cord receives that information from the body, it can suppress that signal, it can amplify that signal, it can misinterpret that signal as it goes to the brain.”

8. When you give some love to the tissues, you can heal the issues. Jill Miller, “I put out a call when I started writing this book [The Roll Model Method] to ask folks who had been using the Yoga Tune Up® balls for their story and I expected to get a lot of stories about rotator cuff tears, knee stuff, back stuff… all these musculoskeletal things. I ended up getting all these stories  from people with Lupus, or MS, or cancer recovery- there was this disease category. But the category that most surprised me and most filled my spirit are the stories of people who dealt with unbelievable emotional trauma.

I am a psychological runner- a runner from the family dynamics that were not supportive to my own expression of emotion. I shut down in my own way. I starved myself, I threw up, I used my body aggressively. A lot of people wouldn’t think yoga is aggressive but I literally stretched myself end to end and destabilized my body completely. I was that yogini that could do everything- I could do all kinds of crazy-town things. I was in a lot of denial about my own aches and pains, I was in denial about my compulsion to practice. It destroyed relationships, it affected friendships, it affected my job.

Addiction to food is really difficult to deal with. You need to eat to live. I did heal that part and then it transmuted into this other pie-piece of addiction which was an addiction to stretching. Stretching calms you down- that’s one of the great things about stretching. It turns off your stress switch. I was addicted to that because I  was so freaked out on the inside.

I do think that in the exercise and fitness industry the dirty little secret is that there is a lot of body dysmorphia- there is a lot of intense dislike of the body. My goal is for everyone to live playfully and peacefully.”

9. Giving the prescription to "just move more" is missing whole universes of information about what we are truly lacking in our contemporary domesticated human environment. Katy Bowman: “The generalization of quantifying things- like saying an Orca swims in the ocean, so the Orca can swim in a tank, that way the “swimming” box is checked, therefore this [the floppy fin problem of Orcas in captivity] could not be  disease of mechanotransduction.

You need to break down swimming into something more specific. You can call swimming a macronutrient, but if you look at the micronutrients the questions are: What were the distances covered by whales in the ocean? What are the speeds that are normal for a whale to swim? What about swimming in a circle, is that normal?

Where we are with movement is where we were with nutrition 40 years ago. We say, ‘Just move more!’ if a whale in captivity were to just swim more, it would make the flopped fin worse. Moving more might bring about even more of the forces that brought about the disease of mechanotransduction- in this case the flopped fin. It might make things worse.

At the end of the day swimming more wasn’t really the problem. If you walked in a circle everyday, you would notice that your body became shaped to that. Then you walk fast in that circle, it will highlight those diseases even faster.

When we say we need to move well or differently, often we say [in this example], ‘Walk in the circle in the other direction.’ You would offset some of the adaptations with that correction, but it’s still treating the symptom.

Corrective exercise is spot-treating these nutrient deficits by creating something novel instead of pulling back and asking what is the actual problem here? What are my actual movement requirements and how can I actually meet those instead of taking the vitamin or pill equivalent?”

10. Be aware (beware) of relying on momentum. Bo Forbes: “Familiarity and discomfort breed momentum. When we move very fast, and when we’re moving into yoga as exercise (which we know is beneficial, so I’m not saying it is a bad kind of practice), but we use momentum to repeat familiar patterns in the body, and to speed up transitions between poses. This is why things stay the same.

The transition between downward dog and lunge is a place where many of us put our bodies into a box that doesn’t fit them. 80% or so of people have a body whose proportions don’t make that shape well, so that in order to transition between those poses we have to do things- like moving fast- to accomplish the transition and we sacrifice the opportunity to not what might be going on that makes it hard to make that transition.

[When we don’t over-rely on momentum] We’re using our practice to awaken more as opposed to creating mastery. Mastery and mindfulness are almost on opposite ends of a spectrum. Where there is mastery usually by definition we have less neuroplasticity- less new learning- we feel very comfortable in those places. We’ve lost the opportunity to gain new neuroplasticity.

If we practice for many years, being able to tolerate that experience of awkwardness- or not mastery- and even seeking it out... If we start with interoception, we bring our awareness to our body and our breath, and the movement is funded from that place.

Momentum affects other parts of our lives- getting carried away with momentum to stay in that relationship you shouldn’t stay in, or that job you don’t want to be in… Our practice can allow us to colonize new areas of awareness in our lives. So if we get angry- and we have difficulty experiencing sadness- cultivating the time to notice that vulnerability underneath the anger can happen via interoception.”


Pure gorgeousness. I'm so grateful to all these people for the good work they are doing in the world. And next week I'll be back with ten more shiny golden nuggets of wisdom from season one.

image by Leo Reynolds

Dr. Stephen Levin: Biotensegrity (LBP 035)

Dr. Stephen Levin originated the concept of Biotensegrity more than 30 years ago. He originally trained as an Orthopedic and Spine Surgeon and was formerly Clinical Associate Professor at Michigan State University and Howard University. He studied General Systems Theory with noted biologist, Timothy Allen, and now, retired from clinical practice considers himself a ‘Systems Biologist’. He has been closely allied with others working in the field of Design Science, emphasizing the work of Buckminster Fuller and its applications. He has written numerous papers that contribute to the understanding of how biological structures function like tensegrity structures.

In our conversation today we get into, well, first and foremost what biotensegrity is, the many ways that we are not like skyscrapers, how the difference between the bicycle wheel and the wagon wheel can illustrate the concept of how we are “pre-stressed”, what viscoelasticity is, the scapula as a sesamoid bone (every bone as a sesamoid bone really...), some examples of the many tensegrity structures we can find in nature if we know what we’re looking for, what the ichosahedron has going for it and why we should care, and more!




Show notes

Brooke:            For those unacquainted can you give us a simple, kind of nutshell definition of what biotensegrity is?

Stephen:          Tensegrity is a word derived from tension and integrity which is a Buckminster Fuller term to indicate a continuous tension network. It's actually more than that. It's the compression elements of the structure are meshed within the tension elements so that the compression elements, the rods, the skeleton, do not press on one another.

It was derived from Kenneth Snelson's  sculpture actually [Needle Tower, in resources]. Snelson was student of Fuller but it was Snelson who really made the first structure. He describes it as a closed structural system composed of three or more compression struts within a network of tension tendons. He says the compression rods float within this structure and they press outwardly against the tension member so it's a self-contained unit, and it's pre-stressed tension and compression unit. Tensegrity as a word sort of had lost its meaning so that we put bio in front of it, which is a biology adding to it, and it's really more narrowly defined and more specific than using tensegrity, which everybody uses for everything else. You can get away with things in tensegrity you just can't get away with in biotensegrity because lifeforms have their laws that they have to stick to.

Brooke:            The difference between the mechanics of a bicycle wheel as opposed to a wagon wheel- that's a nice illustration of how we are pre-stressed. Can you talk about that a little bit?

Stephen:          Aside from the Snelson sculptures, the closest you get to everyday life as a tensegrity is a bicycle wheel where the hub is suspended in the middle of a tension network of spokes. All your spokes are always under tension. In a wagon wheel, each spoke bears the full weight of the wagon, of course divided by the number of wheels you got on the ground. Each spoke bears the full weight and you actually are vaulting from one compression pillar of the spoke to the other compression pillar of the spoke.

The bicycle wheel, it works the opposite. All the spokes are working all the time. When you set a bicycle wheel, you tighten all the spokes, you pre-tension them, and then it stays that way even when you ride on the bicycle. Your load is distributed through the tension elements of the spokes. All the spokes are pulling on the hub all the time. It's by the opposite pulling of the spokes that the hub stays in place. It's like if you were doing tug of war and you had an equal side and the rope wasn't going anyplace. They're not staying right in the middle because it's equally pulled on both sides. Just as the spokes in that bike wheel are pre-stressed, all the tissues in the body are pre-stressed. They are always under tension. So muscles are never programmed lax. There's always muscle tone present. All the fascia and connective tissue, in fact all collagen have intrinsic tension within them. Even under deepest anesthesia, when you cut muscle it retracts and pulls apart. There's always tone to muscle, and you can never say your muscle is completely off.

Brooke:            I think that's a beautiful illustration. Speaking of visuals, you say that tensegrity structures are ubiquitous in nature if you know what to look for. Can you give some examples of what we might be able to notice if we do know what we're looking for?

Stephen:          There are no true man made tensegrities because even the man-made tensegrity structure itself uses the linear materials, the regular materials people build with. Tensegrities in themselves are non-linear, and we'll probably talk about that later. They're ubiquitous in nature; it's just recognizing them. Most of the obvious ones look like the Buckminster Fuller geodesic domes, like the Disney Epcot Center. Those can all be built as tensegrities. My favorite one is the dandelion puffball because that was of course a large structure that I recognized as being consistent with a tensegrity. The concept has been around for a long time. Icosahedrons were described in the mid-1960s I think it was in the lymphocytes and red blood cells, pollen grains, when you get down to the little things, but if you start looking at bigger things, things like raspberries and similar fruits and berries, puffer fish. In fact, most round spiky thinks are pretty obvious tensegrities when you look at them. Tensegrities actually can be recognized more from the mechanics of the structure than its outward appearance.

Brooke:            That makes sense. On the opposite side of the spectrum, bioengineers oftentimes will describe human bodies or say that they are like skyscrapers. What are some of the many ways that we are not like skyscrapers?

Stephen:          Tensegrities are built up from smaller units. In biology, the subunit, the cell of the tensegrity structure is the icosahedron, which is polyhedron with 20 triangular faces, and triangles are the only structures that are inherently stable with flexible hinges. These structures can have any outward appearance, from spheres to towers with limbs sticking out. It doesn't make any difference. They're all self-contained entities. They don't require gravity to hold them together.

Skyscrapers and towers need gravity to hold them together. The bottom bricks are held in place by the bricks above them, one on top of the other. When you build a skyscraper, the base has to be bigger and stronger and stiffer than the top, and if you tilt the tower over it not only will fall over, but it will pull itself apart because of the intrinsic sheer forces that develop. If you build biotensegrities, they really join together like bubbles in a foam and they sort of share walls and structural continuity.

If you go back to towers, I lived in Washington, D.C. area, and the classic model might be the Washington Monument, which is 550 foot tall, it's 30 foot thick at the base, it's five foot thick at the summit, and it's built stone on stone on stone held together with rigid mortar. The Washington Monument was almost toppled in an earthquake a couple of years ago. It got shaken up and got cracked because it has no flexibility in it. Trees on the other hand are broader at the top. They have much more weight at the top than the bottom. They withstand big winds, and they're sort of built upside down from a Newtonian concept.

You stop and think about animals including ourselves- we have our small and light bones in our feet. We actually stand on two little sesamoid bones under the first metatarsal, a little thing at the fifth metatarsal, and the heel bone, the calcaneus, which is as soft as eggshells. So we stand on our calcanei and of course we often have dense heads that put a lot of load on these structures. We're built upside down. We don't make sense in a Newtonian concept. All biological structures also have flexible joints, and we are omnidirectional. We don't break apart when we're turned upside down and shake it.

Brooke:            I like how you mention that we don't need gravity to hold us together. When we have people who go into space or even just diving in different pressures under water and things like that, that we don't come apart.

Stephen:          It's one of the characteristics of the tensegrity structure that is independent of these outside forces. It holds itself by internal forces.

Brooke:            It's interesting, and the foam, the soap bubbles is a really nice one too because that's something we can interact with pretty regularly.

Stephen:          We essentially are foams.

Brooke:            I love that image. We are foams. You had mentioned icosahedron, which is pretty important I think to the concept of tensegrity. Can we break that down a little bit more and why we should care about this structure?

Stephen:          When I started doing this, I tried to find some structure that looked like a cell and that would build from a cell. The icosahedron is one of the platonic solids going way back. It's a fully triangulated structure. Again, only triangles are inherently stable, so if you're going to have flexible hinges, you have to be triangulated. It's omnidirectional so that you can turn in any direction. It has the largest volume for surface area, so it's energetically in the sense of using materials that are most economical. It can be close-packed to fill space or would fill spaces like cellular space filling. It joins together. When it does join together, it'll share structures. It's like sharing the faces in the bubble, as we pointed out. The individual icosahedrons can actually then function as a one unit structurally, but it also has the ability to function as the individual unit. They become independent and interdependent at the same time. It can have an external or internal skeleton. You can internalize the compression elements instead of keeping it in the outside shell, and that internal creation is a self-emerging property that comes from the structure itself. It also has mechanical properties that are non-linear, viscoelastic, which is the same as biologic materials, so why wouldn't you use it?

Brooke:            Can you describe viscoelasticity a little bit more, since you just dipped into that a bit?

Stephen:          Viscoelastic suggests the material property has some qualities of a liquid, the viscus part, which is liquid, and some qualities of so-called the solid part, the elastic part. Elastic just means that the form may never return to its previous shape. The rubber band elastic is not a really good elastic. When you apply the term viscoelastic to biologic material, it's really a misnomer. Biologic materials are not hard matter; they're called condensed soft matter, or just simply soft matter. As a class of behavior, the hard materials side has been described as viscoelastic, but it's really a breed of its own.

The best example I can give you of this is silly putty and the green slime that the kids play with. If you recognize silly putty, it's a polymer, it's a mixture of things. Sometimes it's rigid, sometimes it's soft. You can bounce it. You can do all sorts of different things with it, and it behaves differently the different ways you load it. It depends on the rate of loading, the surface area, the temperature. By temperature, I mean only a few degrees. We operate in a very few degree level. Steel, you need to really get it hot. Biologic things have very slight temperature changes can do different things. The silly putty and the biologic density can be malleable, brittle, elastic, all these things at the same time.

Soft matter physics is the science of gels, foams, emotions and some composite mixture like cornstarch in water will show these kind of behavior. The Oxford University Lab actually has on their website, "Biology is soft matter come alive," and that's a quote right off their website. If you think as foam as behaving as silly putty, as it probably does, we have all these properties built into the viscoelasticity and the characters of biologic tissues. All the structures in biology behave the same as icosahedrons do, which have this viscoelastic property, which really isn't that, it's soft tissue mechanics.

Brooke:            You mentioned the cornstarch and water thing. We used to use that at the Rolf Institute just to get a tangible sense for viscoelasticity, and it's really fun if you mix up a tray of it because if you touch it hard and fast, like with really pointed fingers, it just firms up like a wall and kind of pushes you away. If you touch it slow and broad, your fingers will sink in and then getting your fingers out, if you pull real quick, it'll keep you in there. It's really cool to play with that quality with touch and to get a sense for how responsive it is.

Stephen:          I frequently use the example when you pull on your lip or your earlobe, and you'll get that kind of sensation where you can pull, it'll first give easily and then it stiffens up as you pull on it. It's not a linear stiffening up where you get an incremental point by point. It actually gets structurally stiffer in many ways. The harder you pull, the stiffer it gets. The silly putty gets stiffer the harder you pull on it or the faster you pull on it.

If you look at things like fascia for instance, then you're right, just as you play with it that the fascia does that. If you attack a body and push on it hard, it's going to resist you. You'll never get into its deeper layers. If you just sort of lean on it and move into it slowly, you'll get into the deeper tissues of it, and that's very typical of these kind of things. If you think silly putty or these slimy gel things, you'll see that's exactly the way it works. You look at something like the heel pad for instance. You run on your heel pad, and every time you hit it hard it protects you. When you walk on it, it gives you a soft, gentler kind of response and a more of a shock absorber, and if you touch it you can just sort of sink your finger into it. It's the same material. It depends on the rate of loading it that makes the difference.

Brooke:            You mentioned how delicate a structure our calcaneus bone is, that heel bone, and that this model of us like skyscrapers just doesn't hold up. If we were loading it that way with all the force of everything else piling down on top of it, they wouldn't last us very long.

Stephen:          The calcaneus is really very soft bone. If you get it in surgery, you can actually just poke at it and it'll break just by poking at it. It's really quite soft. One of our problems is that when you take these things out of the body and let them dry out, they become stiff and hard, and you're not dealing with them under normal test conditions that the body uses. If you're testing things at room temperature, well the body doesn't operate at room temperature. It operates at body temperature. If you take a thing like petroleum jelly, you keep it at room temperature and it's a thick jelly and you put it on your skin, it just slides all over the place. You have to now think of how are these people testing these materials outside the body? If you're not testing it at room temperature and using body conditions, then you got completely different results.

Brooke:            That makes perfect sense. You point out that in the traditional paradigms of Newtonian biomechanics, these are some examples you gave: “The forces needed for a grandfather to lift his three year old grandchild would crush his spine, or touching a fish at the end of a fly rod would tear the angler from limb to limb.” I think these are some good examples about how this bioengineering Newtonian model doesn't really hold up to how we actually use our bodies.

Stephen:          Rather than go through the math with you- it's difficult without a blackboard- let me point out at the Newtonian biomechanics calculation of spinal loading and joint muscle loading are based on a 350 year old model that assumes biologic material is hard matter, and we just discussed that it is not. We now know it's more like silly putty. That muscles act as binaries because they're on and off. We've already talked that muscles are always on. There's always tone in muscles. The assumption is that the muscles act as agonists and antagonists, when they mostly act synergistically. That the muscular system is an open kinematic chain system, one we know that much of if not all of muscular skeletal mechanics is really closed kinematic chains. We move one thing and something moves at the other end of this chain. You also understand that muscles are internal forces and can't resist external forces without external help. They're using the calculation as if the internal muscles can resist gravitational forces, and they cannot. You can go through all this and I don't have to use calculations or any math. I can just talking about this and say, "Hey, they're using the wrong model. You got to start over again."

Brooke:            Perfectly said. We dipped into this a teensy bit, but going back to it, biologic systems are pretty invested in using the least energy expenditure necessary. What are some of the ways we've developed to use the least energy needed?

Stephen:          I'm old enough to been in the Army, and the Army maxim was, "Never stand when you can sit. Never sit when you can lie down. Never stay awake when you can be asleep," and that applies to biologic systems. A non-linear stress strain curve is initially flat. The disc is flat. It just sort of flows along and then starts getting stiffer and stronger. The biologic system always wants to operate at the least energy point at the low part of the curve because as you increase that strain and it gets stiffer, you need much more energy. It's interesting that in the laboratory, most of the testing is done on the steep part of the curve and they sort of ignore the bottom part because the math there is very difficult.

Brooke:            That's interesting to know. Diving into one structure in particular here, the shoulder is one of the least successfully modeled joint complexes using Newtonian mechanics, and you have a great paper on this, which I'll put in the show notes. It's titled The Scapula is a Sesamoid Bone. I love that image. For those listening, can you briefly touch on what a sesamoid bone is and how the scapula functions as one?

Stephen:          The sesamoid bones, are those bones considered outside the axial skeleton that don't contribute to direct support of the body. Of course they're thinking of the body that has a column of bones, and the most common one that everybody knows about is the patella, the kneecap that sort of floats outside the knee and is buried within the tendon of the quadriceps muscle. There are others. One you don't think about very often is the hyoid bones in your neck where your voice box is. There are bones there, and that's sort of sitting in space not supporting anything. Of course while there are supporting ones, but not thought of those, are the two little sesamoid bones underneath the first metatarsal. These things are about the size of small peas, and they crush easily. They are like peanut shells. They'll just crush very easily and they're sitting there, and you'd expect it to get all this force. They're sitting in tendons, and those tendons act like leaf springs on a car and actually keep you from striking the bottom there. If those little sesamoids got hit by the first metatarsal, they'd be crushed like hammering against enamel.

I looked at the scapula, and the scapula sits there and it floats inside the chest wall. There's no direct loading between them. It's buried in muscles. It fits the definition of a sesamoid. Of course, I take it a bit further and I say in the biotensegrity model all bones float because that's a definition of tensegrity, and therefore all bones are sesamoid bones.

Brooke:            Right, yeah, because the scapula, we'll think about that continuity with the clavicle bone, for those of us who are anatomy folks. That doesn't mean that it's not floating just because it has that bone nearby.

Stephen:          If you look at the clavicle, it's also floating up there. It's only hinged to the sternum by a little ligament there at its joint, and of course the chest wall is moving up and down 16 times a minute through these flexible ribs, so there's no way you can pass a load through the chest to the axial spine.

Brooke:            Thank you for that description of the float of the scapula and the float of everything. You've been working in the biosentegrity field for a long time and you've contributed a lot of wisdom in this field. Is there anything that you're currently really fascinated by in your own work?

Stephen:          Actually this year is my 40th year working in biotensegrity. My original concept was sort of a eureka moment 40 years ago when I was sitting outside the Natural History Museum in Washington, D.C. contemplating the skeletons of dinosaurs when I recognized Snelson's sculpture across the lawn. The museum there where his sculpture is is directly across from the Natural History Museum, and I put the two together and then started building from there. Since then, I have been working on this concept and trying to figure out how these two mesh together.

The most recent things I've been working on have been the soft matter physics and the closed kinematic chain mechanisms, which are how these structures move and how they behave under different forces, which completely gets you away from the hard matter physics that is the staple of the present day biomechanics.

Brooke:            Wonderful. That was a really fortuitous day at the Natural History Museum to see those two things together.

Stephen:          The Hershell Museum opened a year before and I had gone down to the museum and walked around and couldn't figure out how this structure stood there. I just left it at that. I was a year later, sitting across the mall and I said, "Oh my god, the two of them match." I went across and then figured out from there, and then it took me a long time to figure out how to build the tensegrity. I called Snelson and got hold of Buckminster Fuller people and I did all sorts of things to finally figure it all out and get down to the icosahedron and then work back up from there.

Brooke:            That's wonderful. Those giant dinosaurs couldn't have really existed with this structural skyscraper model.

Stephen:          Absolutely not. There's no way that they could have functioned in any way but a tensegrity concept. Even more than anything else, the Diplodocus had a tail that was over 100 bones long and was held up in the air. It didn't drag on the ground. It used to whip around. There's no way that that that could have functioned unless it was in a tensegrity structure. The muscles are adjacent to the bone. There's no lever that you can possibly make out of it, so it has to function as a tensegrity.

Brooke:            My son went through a very intense dinosaur period for a long time, so I'm pretty well versed- Because the tails were so long on these skeletons they were finding, they just always assumed and created the skeletons with the tail dragging on the ground until they finally realized they'd never found a fossil with a tail drag.

Stephen:          Exactly. That was my professor. I was trained by the head of the Paleontology group over there, and he used to say, "In the sands of time there are footprints but no tail tracks."

Brooke:           Which means we have to think of these things totally differently than we have. Thank you so much for all of the amazing work that you have been doing and for talking with all of us today.

Stephen:          It has been my delight. Thank you very much.

Home play!

Let's play with viscoelasticity by getting in touch with our preschool selves. Either get yourself some Silly Putty, or make a cornstarch goop. How you ask? The recipe is right here:

  • Grab a large-ish tub of some kind. Flat on the bottom is best (because then maybe you can even stand in it- jump on it and it's firm, stand still and you sink.)
  • Add cornstarch
  • Add water very slowly and stir. You will know when you have added enough water when it's consistency gets goopy but not too liquid.

Then- once you have either Silly Putty or the cornstarch goop- you can play with its viscoelastic qualities:

Pull the Silly Putty apart quickly and it will snap and get more brittle. Pull it apart slowly and it will get soft like warm taffy.

With the cornstarch- touch it firmly or quickly- slap it, poke it, etc and it will firm up like a wall. Touch it broadly and softly and it will soften and become more like  a liquid. The same goes for getting your hand out of the goop: pull your hand out quickly and it will firm up and hold on to you, pull your hand out slowly and your hand will be released.

Now you know what working in fascia feels like! And you have a better sense for how our bodies operate in both a viscous and elastic state simultaneously. Have fun!


Biotensegrity- Stephen Levin's website

Buckminster Fuller Institute

Kenneth Snelson's Needle Tower sculpture

How Does the Hirshorn's 60 Foot Needle Tower Stay Upright in A Stiff Wind- Smithsonian Magazine (includes video of its installation)

Tensegrity the New Biomechanics

The Scapula is a Sesamoid Bone

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