The picture Ida wanted to replace
Ida's first move, in nearly every advanced class where the tensegrity question came up, was to dismantle the picture students had brought with them from anatomy school. The standard image — the one drawn in every textbook and reinforced by every articulated skeleton hanging in a classroom — was that bones stack like plates, each vertebra carrying the load of everything above it, with muscles draped on top as movers. The structural school of healing had once known better, Ida argued, but had been displaced when chemistry rose to dominance in late nineteenth-century medicine. By the 1970s she was claiming that a more basic way of thinking about structure was finally returning, and that what made the new way different was its insistence on the gravitational field as the determining factor. The body's job was not to hold itself up by stacking bone on bone; the body's job was to organize itself so the gravitational field could pass through it without disorganizing it.
"And only now, this is coming up again, And And I am saying to you, and I don't get to how many people say this, that we have a more fundamental way, a more basic way of dealing with structure Now the reason we have this way is because we have become sufficiently sophisticated to understand that structure is determined by the relationship of the individual body to the gravitational field. This is what often has offered in addition to any other school. What's the difference between this and this? Is the answer. We are the only group who recognize that in order for a living body to be at ease in its spatial environment on the earth, it must deal positively with gravity or rather gravity must deal positively with it. Because what we here in Lawton are here to do, we can't change the gravitational field. This is odd, but we just have nothing that means yet. But what we can do is to change the way the parts of the body that I have already referred to, how they fit together into a whole which can transmit the gravitational field. And in its energy, which is the energy of the earth, in its transmitting of that, it enhances its own energy field. You can change the body by virtue of the fact that its segments are segments of a whole and then the gravity can flow through. Now this is the basic concept of Rolfe. And tomorrow when I get you all together on the griddle, I'm going to ask you for this answer over and over again in many, many different forms."
In the 1973 Big Sur advanced class, Ida sets out why her work is structural rather than chemical or postural:
Once she had pushed the chemical-school picture aside, Ida moved to a still more specific claim: that the soft tissue, not the skeleton, is the actual organ of structure. The fascia holds the body up; the bones are passengers in that web. She made this point repeatedly across the public tapes and the advanced classes, often with the same image — scoop the contents out of an orange, leave the skin, and you still have an orange-shaped object. Scoop the chemistry and the organs out of a human being and you would, in theory, still have a human-shaped body of fascia. This was the picture that prepared the ground for tensegrity: if the structural organ is a continuous tensional sheet, then the bones inside it are not stacked plates but spacers held apart by the web.
"You are going to be getting more and more intimate with collagen which before you heard it well could mean you didn't know existed. But you see, it is the connective tissue which is the organ of structure. The fascia envelopes are the organ of structure, the organ that holds the body appropriately in the three-dimensional material world. Now nobody ever taught this in the medical school as far as I know. And anytime you want to get into an argument with your medical through they'll realize that this is so. It is the fascial aggregate which is the organ of structure. And the structure basically the word, where we use the word structure, we are referring to relationships in free space. Relationships in space. There's nothing metaphysical metaphysical about it. It's pure physics as it's taught in physics laboratories."
Continuing in the same 1973 Big Sur class, she names the fascial body as the organ of structure:
Bones as spacers, not stackers
The clearest statement of the doctrine — bones do not hold the body up; bones hold soft tissue apart — comes from a public lecture preserved on one of the soundbyte tapes. Ida uses the camping tent as her teaching image. The tent pole goes up under the canvas, and the canvas is pulled down by ropes tied on both sides. The pole alone cannot keep the tent standing; the tensioned ropes do that work, and the pole's only job is to keep the canvas from collapsing onto itself. The pole is a spacer. The body, Ida argued, works the same way. Bones are the spacers inside a tensioned fascial web, and what keeps a person upright is the balance of the tensions, not the stacking of the spacers.
"Bones hold soft tissue apart. Those of you who camped in the days when a tent was instructed that looked like that, remember what it was like to put that tent pole in under the plastic canvas. You had to get your tent pole precisely formed in order that you could take your canvas and you could tie it down with tie ropes so that the left side counterbalanced the right side."
From the Topanga public lecture, the doctrine in its simplest form:
The spacer doctrine had a consequence Ida pressed on her students: if bones are not stacking weight, then the entire mental picture of structural work changes. You are not adjusting plates that have slipped out of register. You are adjusting the tensions of a web so that the spacers float into their proper positions. This is why she insisted the work was on the myofascial tissue and never directly on bone — the bones move because the tensions around them have been reorganized. In the same public lecture she walked through the corollary: the body is not a single squat thing like a tent pole but a series of blocks whose centers of gravity must be in vertical alignment with one another for the assembly to be stable. The tent analogy and the stacked-blocks analogy were not contradictions; they were two ways of pointing at the same requirement, that the soft tissue must be balanced for the bones to find their places.
"And either they balanced and balanced well, or when the when the winds really struck that night, the tent was down on top of you. The right side balanced the left side. The left side pulled down in order to pull the right side up. And the same thing was true of the front and the back. A body is rather like that. There are other things to realize about a body. It's not a squat single thing like a tent pole, like a tent plus tent pole. It's more like a series of blocks and those blocks need to be stacked. And you people all realize that you were all of two years old when Uncle Joe gave you some blocks And it didn't take you very long to know that if you were going to get a stable stacking of blocks, you could only stack it in one fashion. And we'll see a little bit more of that in the pictures that I'm going to show presently. The centers of gravity of each block had to be in a vertical line with the center of gravity of the block above and the block below before it was possible for those blocks to form a stable form. And this is part of the story of bodies. All bodies can be looked at as being aggregates of blocks, big blocks I mean, blocks like the head, the thorax, the pelvis, the legs."
She extends the tent image into the stacked-blocks picture:
See also: See also: Ida Rolf, public lecture material on structure as relationship versus posture as effortful placement (Topanga clips), where the structure-versus-posture distinction is given its sharpest form. Included as a pointer for readers tracking how the tensegrity doctrine fed into Ida's larger vocabulary of structure. TOPAN ▸
Jim Asher builds the icosahedron
In the Boulder 1975 advanced class, the tensegrity model received its most sustained workout. Jim Asher had been building physical tensegrity structures — wood-and-string models of the kind Kenneth Snelson had pioneered under Buckminster Fuller — and brought them into the classroom for the students to handle. Asher's purpose was to give the doctrine a tactile demonstration: here is a real object built on tensegrity principles, here is what it can hold, and here is what it cannot. The first model he built was the tensegrity icosahedron — twenty triangular faces, struts that never touch one another, held together entirely by the tension of strings running between strut ends. He had spent months staring at it before something shifted in his understanding of what it was teaching.
"The first one I built was this, one here which is called the tensegrity icosahedron. It embodies the same principles as this namely that if it's a vector equilibrium and if you trace the lines of force that are the result of these strings all being pulled, you find that they run right down the struts and the same in this direction so the whole thing balances."
Asher describes the first model he built and the moment its principle became visible:
The revelation that came to Asher had nothing to do with the icosahedron sitting upright in its normal orientation. It came when somebody — he could not remember who — rolled the model over so that it rested on its side, and Asher noticed that in this position the struts themselves did not touch the ground. The object was sitting on its strings. If you put a weight on top of it, the strings carried the load. The struts, the rigid members, were not in contact with the supporting surface at all. This was the picture Asher believed mapped onto the spine: the rigid pieces — the vertebral bodies — might not actually be stacked plate on plate, and the load might be carried by the surrounding tensional web rather than by the bones themselves.
"that if you put if you use steel struts here and strong wire on this, you can support a very large weight on it. You can put several 100 pounds on it easily and sit it on the That is full of story. Right. And the thing is that you then it's enormously more efficient way of Does that hold so long? Supporting weight. This won't. But a structure made of steel struts and wi"
Asher works out the load-bearing efficiency of the model:
Asher's enthusiasm did not yet have full mathematical backing, and he was honest about that. He had spent an afternoon at the UCLA library looking for technical literature on tensegrity structures and had found almost nothing — the field was still treated as a kind of curiosity, with most of the working knowledge held by Buckminster Fuller's circle in Houston and a handful of his students. Ida, who had her own network, offered to put him in touch with three of them and mentioned that she had already sent his paper to one. The exchange shows the working method of the Boulder class: a hypothesis brought in by a colleague, the senior teacher pressing for evidence, and the room collectively trying to figure out whether the model would survive contact with what they could actually see in bodies.
"Of course, what I'm trying to discover is the mathematical principles so that I can apply it particularly to the structure of the spine as being the first candidate for seeing whether this sort of thing can apply to it. Now, as I argued in the paper, it seems to me it has to be. Well, I think it has to be too. If there is such a thing, it has to be. Right. I mean, this is but the question is the details. But the guy that could tell us is really this this man in Houston. Mhmm. I don't think we can get him over here. Anyhow, it's all yours. I'll be still now, but I after all, people want to know those two things. So in a way, I mean, I've been staring at these things for so long now that it's all becoming slightly self evident to me. It wasn't, of course, self evident at all when I first started to build things. The first one I built was this, one here which is called the tensegrity icosahedron. It embodies the same principles as this namely that if it's a vector equilibrium and if you trace the lines of force that are the result of these strings all being pulled, you find that they run right down the struts and"
Asher describes his difficulty finding technical literature, and his hypothesis about the spine:
If the spine is a tensegrity, what carries the weight?
Asher's central question — the one he and Roger had been turning over together — was structural and specific. If the spine works on tensegrity principles, then the obvious functional part, the round disc-shaped vertebral body that everyone assumes carries the load, may not actually be doing the work people assume. Asher had spent years looking at skeletons and accepting, without question, that each vertebra held the weight of everything above it. Ida had told him this was not true, and he had at first refused to believe her. It was a paradoxical claim, and the cervical and lumbar vertebrae were so obviously shaped like weight-bearing pieces that the contrary view seemed wild. But once he started looking, he noticed something he had previously overlooked: behind the body of each vertebra sits a triangular structure — the spinous and transverse processes, the neural arch — and triangles, uniquely among geometrical figures, are non-deformable.
"is what if the spine is a tensegrity structure, then what exactly is the functional part of the spine? What is it that holds the weight?"
Asher poses the founding question to Ida and the Boulder class:
Asher continued the thought by walking the room through the geometry. The big round disc-shaped vertebral body, he conceded, looked like the obvious candidate for the weight-bearing piece. But behind it — dorsal to the body — sits the neural arch, with its triangular processes extending outward and backward. Triangles, Asher pointed out, are the only geometrical figure that cannot be deformed without breaking. A square can be pushed into a parallelogram; a triangle, made of rigid sides, cannot. This is the principle Buckminster Fuller's geodesic domes rest on, and it is the principle the tensegrity icosahedron rests on. If the spine were a tensegrity mass, its triangular components — the neural arches — would be the rigid spacers, and the lines of force would run through the surrounding tensional web.
"if the spine is a tensegrity structure, then what exactly is the functional part of the spine? What is it that holds the weight? Now when you look at a vertebra, you look at that big round disc shaped creature with the disc on top of it. Think, that's got to be the part of it which is maintaining the weight. But if you look"
Asher works the geometry through, from the vertebral body to the triangular processes:
If the neural arch was the structural unit, then the vertebral body — the part everyone had assumed was the weight-bearer — must be doing something else. Asher proposed, tentatively, that it functioned as a shock absorber. He had found a piece of experimental data to support the proposal: someone, somewhere, had performed the test of taking a lumbar vertebra and pressing on it from above until it crushed, and the figure that came out was about two thousand pounds. Asher used this to argue that since a person can at most lift around two hundred or two hundred-fifty pounds, a structure with a roughly ten-to-one safety margin between load and breaking point makes engineering sense as a shock absorber rather than as the primary weight-bearing element.
"that if you take a lumbar vertebra and you put"
Asher introduces the experimental data he has been able to dig up on vertebral body crush strength:
Asher walked the class through the engineering logic. If a person lifts a two-hundred-pound weight from a bent-forward position and you treat the spine as a stack of plates, the lever arithmetic produces something like a ton of pressure at the lumbar vertebrae as the weight is brought up. That is an inefficient way to build a structure. But if the spine is held up as a tensegrity — the tensional web carrying the load, the vertebral bodies absorbing only peaks — then a structure built to take two thousand pounds of crushing force makes engineering sense as a shock absorber with about a ten-to-one safety margin against the maximum load a human can actually lift. Asher was careful to note that he was arguing from coherence rather than from evidence. He had a hypothesis, not a proof, and Ida pressed him on this honestly.
"That's to say the thing would be the structure would be 10 times stronger than what the kinds of pressures you put on it. And that would seem to me to be, if I were building it, a logical way to build it. If you take the figures, if you, on the other hand, treat the spine as though it were a stack of plates and then if you calculate what happens when somebody bends down and picks up a weight, a 200 pound weight and picks it up here, then you get calculations demonstrates you get at least a ton of pressure here in the lumbar vertebra as you pick the thing up this way which seems to me to be an inefficient way of doing it. So just on the using as a kind of a priori principle of efficiency, it would seem to me this is a better way of looking at how the spine functions than looking at it as a series of plates one stack on top of the other. Does that make sense? I mean that's an argument again which is sort of taken out of the air. I haven't the evidence for this yet but it's It's a hypothesis. Yeah, right. I'm always in this thing arguing from coherence rather than from evidence at this point and I want to go and find the evidence for it to see whether or not it will work out like that correctly. Now, how are you going to get to that tensegrity mass, that upright of the human from the horizontal of the animal? Have you given any consideration to this?"
Asher works out the shock-absorber arithmetic in detail:
The anatomical evidence: trabeculae and cortical bone
A few days later, in the third tape of the Boulder series, a different student brought the discussion back with a piece of anatomical evidence Asher had not yet cited. The student had gone to the library and looked at sections of vertebral bone, and what he found supported the tensegrity hypothesis more directly than Asher's a priori arguments. The head of the femur and the bones of the leg are famous in anatomy for showing trabeculae — the internal lattice of bone tissue that organizes itself along the lines of stress the bone is actually carrying. If a structure bears load along a particular vector, the trabeculae form along that vector. The vertebral bodies, the student reported, do not show stress lines in their trabeculae the way the femur does. And more striking still, the cortical bone — the dense outer layer that thickens where load is greatest — is very thin on the vertebral body, but substantial on the neural arch, the spinous process, the transverse process.
"that not only does the vertebral bodies not have stress lines in them, but the compact bone layer, the cortical bone layer on the vertical body is very thin compared to in the spinous process, the transverse process, the whole neural arch So it would seem just from looking at it that the bodies are not weight bearing structures that the main compression structures there are actually the neural arch."
In the Boulder 1975 class, a student reports from the anatomy books:
This was the kind of finding the Boulder room had been waiting for. Bone, as every student knew, remodels along Wolff's law: it lays down material where it is stressed and resorbs it where it is not. If the vertebral body were the principal compression member of the spine, its cortical bone should be thick and its trabeculae oriented along the vertical axis of compression. The actual finding — thin cortical bone on the body, thick cortical bone on the neural arch, no stress pattern in the body's trabeculae — argued that the body of the vertebra was not the compression structure. Whatever was carrying the load, it was not running through those discs. Ida's response in the moment was matter-of-fact: yes, and the compression lines would not be horizontal either, they would run in some other direction entirely. She also pointed out that average bodies, which have collapsed into compression patterns over decades, do not look like compression structures even where they have been forced into that role.
"Yeah. Right. And the compressions are gonna be in different. They're not gonna be in horizontal lines. Right. You see all one of the misleading things about those sections of femur and so on is that they are all average bodies. Right. And using their bones, they carry the weight around. But so are so are these vertebrae. Yeah. And even in even in average bodies, the vertebrae don't look like compression structures at all. Inadequate compression structure. When they do get when they do start to get compressed, they start to get wedged. But but in the average random"
Ida responds to the trabecular finding:
Suspension bridge, cantilever, tensegrity: an evolutionary chain
In the 1976 teachers' classes, Jim Asher offered a developmental framing that placed tensegrity at the end of an evolutionary sequence. The quadruped, he proposed, was structured like a suspension bridge: the spine hung between two girdles like a deck slung between towers, the pelvic girdle in particular doing visible work to suspend the trunk. The ape, knuckle-walking but also rising onto its back legs, was a cantilever — the spine extending forward at an angle off the pelvis, supported by the heavy gluteals and short hamstrings characteristic of partial uprightness. The human, truly bipedal, moved toward a tensegrity structure: a sprung arch in the foot, a spine no longer hung or cantilevered but balanced as a tensional mast. This was not a Darwinian sequence in any strict sense; Asher caught himself worrying it sounded too Darwinian, and the room laughed it off. But as a way of organizing the three mechanical models students might apply to bodies, it gave the practitioner a clear vocabulary.
"Now the when you move into a true biped, you start moving toward that tensegrity because that's when the structure is you have an arch forming, which is like a tensegrity, which has tensegrity components at any rate because it's a sprung arch. And then you have the spine, which moves from being from the suspension bridge to the cantilever to the tensegrity in terms of its evolution. That's what's happening with our development. And a lot of the compression problems that we have are unique to human beings because they're trying to come upright in the gravity field for the first time. So that I mean, I'm just sort of And I don't understand what they can do."
Asher proposes the developmental sequence in the 1976 teachers' class:
The pedagogical use of this scheme was immediate. A practitioner looking at a client could ask: where is this body in the chain? Short hamstrings, flat arches, an anterior pelvis — these were cantilever features, and the work was to bring them forward through the recipe toward tensegrity. The compression problems Asher worried about — sore lumbar spines, collapsed arches, jammed lumbodorsal hinges — were exactly the failures of evolution he predicted: bones taking loads they would not have to take if the tensional web were doing its job. Failures of structure, as he put it later in the same conversation, were failures in tensegrity, which is to say failures in evolution. The framing positioned the practice itself as a kind of evolutionary catalyst, finishing the move into uprightness that the species had not yet completed.
"Right. Yeah. Diverged way back there. Anyway, just just developmentally that you go from that suspension bridge to cantilevered to tensegrity and that the whole tensegrity idea may yet have a place in our cosmology, you know, we can really peg it and say this is where humans are evolving toward, and that failures of structure are failures in the tensegrity or failures in evolution. I think a lot of Doctor. Miller's ideas will have profound significance for me the moment I can understand them."
Asher draws out the implication for the work itself:
See also: See also: Ida Rolf in the 1973 Big Sur Advanced Class on function changing structure — passages where she names the larger evolutionary claim that human muscular patterns are still actively developing and that structural work participates in that development. SUR7332 ▸
Compression versus tension: when does a bone become which?
Once the tensegrity model was on the table, the question that pressed itself on the Boulder room was whether bones were ever, in fact, in compression — and if so, when. The honest answer the practitioners arrived at was: it depends on the state of the body. A collapsed, granite-like body, standing rigid, has its bones acting in compression because the soft tissue is no longer doing its tensional work. A floating, integrated body has its bones in something closer to tension, the surrounding web carrying the load and the bones themselves participating in the tensional system rather than serving as stacked plates. Joe, one of the senior practitioners, put it directly: when a body floats, the bones are taking on tension; when it stands rigid, they revert to taking on compression. The model was not absolute. It was a description of what a balanced body looked like mechanically.
"So that's Chuck is very anxious to say something. So it's Joe. One thing on the compression and tension, like, in the static model, when people have come in looking like granite standing there rigid hard, I imagine their bones are acting in compression, where in the moving body, bones start taking on tension. In other words, when Norm's knee was spanning or his fibula was spanning, I'll bet you that bone was either nothing in it, no tension, no stresses in it, everything was balanced from top to bottom, or there may have been some tension in it. And I suspect the more you're floating, the more tension goes into the bones and the less compression. Although, I meant it's also an ossulary thing where the bones take on tension and compression. But it's not like the the bone is a space that takes compression. But bone about that bone, though, is, like, when Norm's bone here. What that does is put us looking from here to here."
Joe articulates the conditional nature of the model:
This was the move that distinguished the tensegrity model from the standard anatomical picture without abandoning the standard picture entirely. The classical model — bones in compression, muscles pulling on bones across joints — was not wrong about random bodies; it was simply describing the failure case. The tensegrity model described the success case: a body in which the tensional web carried the load and the bones floated within it. The practitioner's job, then, was to bring the body from one state toward the other. Jack Painter, in the same conversation, articulated this as a contrast practitioners should be able to draw for newcomers — the classical model treats the body in parts; the tensegrity model considers the whole.
"That's how I would approach that the explanation of the whole integrity model by showing how the classical model is taking it in parts. There are parts called the bones which are there to support the weight, and there are parts called muscles which are there to move the bone to join. Good point. What our model is is that both weight and motion is distributed throughout the whole the entire structure. And I would try to illustrate that in in terms of weight bearing by by the way wrong."
Jack frames the contrast for teaching purposes:
The Big Sur 1973 advanced class had already given the underlying intuition. There, working through what it looked like when the deep intrinsic structure of a joint was actually doing its job, Ida and her colleagues had pointed at the idea that a balanced body has a kind of immovable fluidity to its bones — the bones held in place at a very deep level by intrinsic musculature, with the long extrinsics free to do their actual job of moving the levers without having to hold the bones together at the same time. The vocabulary of tensegrity was not yet in the room in 1973, but the working picture — bones held in floating equilibrium by the deep tensional structure around them — was already implicit in how the senior practitioners described what they were trying to build.
"In other words, there's an immovable fluidity to these bones and on these bones act these long motor but that's not really true. The structure of a man really is the relationship of these various parts of So soft that what you have, really, is that you have you have three systems here. You have the bone, and then you have the intrinsics, and then you have the extrinsics. And it's the intrinsics that mediate between your extrinsics and the bones themselves. They provide the structure to the body by providing the proper relationship."
From the 1973 Big Sur advanced class, the pre-tensegrity intuition:
How to popularize without losing the model
Ida's instinct, whenever the room got too excited about a new model, was to slow it down. The Boulder discussion of tensegrity reached a point where the room began debating how to write about the model — an article, a booklet, an introduction for new students. Ida pressed Jack to start it, then pressed others, and dismantled each opening they proposed. One wanted to start with the vertical line. Another wanted to define the tensegrity model first and then apply it. A third wanted to begin by drawing the contrast with the compression model. Ida pushed back against all of these, not because the proposals were wrong but because she wanted the room to find what she called the nickel words — the plain language that would let an ordinary intelligent woman in the corner of the room understand the idea on first encounter.
"I would start with the body as the model of itself, but going about it in a way of first starting out with the most complicated thing, and that's the idea of the fascial planes and their idea of of spanning in the bones as spacers."
A senior practitioner proposes a starting point and Ida pushes back:
The phrase nickel words came from a yoga teacher of Ida's many years earlier: anybody can explain things in two-and-a-half-dollar words, but if you really know them, you can put them in nickel words. The push was not anti-intellectual. It was Ida insisting that the test of whether the room understood the tensegrity model was whether they could say it without jargon. Throughout the Boulder transcripts, the conversation about how to write about tensegrity kept circling back to this question: how to lead with the body as the model of itself, how to draw the contrast with the compression model without losing the reader, how to make the spine-as-shock-absorber claim land without sounding like a scientific paper. The article was never finished in the form they discussed. What survived was the doctrine itself, carried forward in the advanced classes.
"It seems to me that you need to start with drawing a contrast between the tensegrity model and the compression model, and then say that the human body has both capabilities or really both models applied to it, and that it operates more efficiently at one end of that spectrum than the other."
Asher proposes the eventual structure for a popular article:
The tensional web in practice: fiddling with the strings
Tensegrity was not only a theoretical model. In the Boulder demonstrations, Ida used it directly to describe what the practitioner's hands were doing. Working on a student named Pam, she walked the room through a sequence of changes in the neck and shoulders — the head coming up, the jaw angle shifting, the sternocleidomastoid rotating closer to vertical — and as the tensions migrated from one location to another in the body, Ida named the phenomenon explicitly. The work was not pushing on one tense spot until it released. The work was adjusting the tensional web until balance redistributed through the whole structure. She used Asher's vocabulary back into the demonstration, describing what she was doing as fiddling with the strings of the tensegrity mast.
"Now let's see what's going on. And do you all see how those tensions immigrate, migrate? First, it'll be down there, and then you loosen up, and then you find it up here, and then you fuss with this, and it goes down there, so forth and so forth. So that there really is no specific direction. It's the fiddling with the strings on the tensegrity mast. That's right."
During a hands-on demonstration in the Boulder 1975 class:
This was a substantial shift in how Ida described the work to her advanced students. The first-generation language of Structural Integration had emphasized stacking blocks, lengthening shortened tissue, releasing fascial restrictions in particular planes. The tensegrity language did not replace those descriptions, but it gave them a different organizing picture. When you released a restriction in the lumbar dorsal hinge, you were not just freeing a stuck piece of tissue; you were adjusting one string in a tensional web, and the consequences would propagate through the whole structure in ways the practitioner could not fully predict. The migration of tensions Ida described in Pam's demonstration was the practical signature of the tensegrity model — the body responding as a whole to a local intervention.
"Know that each horizontal that you bring out down below reflects itself upward as we saw in Takashi yesterday where he's working on his leg and you can see his rib cage absorbing the change. I mean this, when the tissue is in tension, that's stored energy that you release into the body. And its energy is not a metaphysical something. These molecules are aligned in a particular way. You change their alignment. The change spreads."
A senior practitioner names what stored fascial tension actually is:
The same migration of tensions showed up in the Open Universe demonstrations the year before. There, working publicly on a student while the room watched, a practitioner described placing his hands where tissue felt stuck and then waiting for the tissue itself to begin moving — a warming, a melting, a sense that the fluid substance between the fascial layers was being reabsorbed. The description was not yet given in tensegrity language, but the mechanism it pointed at was the same: a local adjustment of the tensional web causing change to propagate through the surrounding structure as the molecular alignment shifted.
"Like there's an in between force between my body and your hand and that it is moving. It's just moving by itself. Now you can feel that I can feel that his spine is dropping back more, especially through this area now. As he breathes, there's more movement in his rib cage. You see fascia gets stuck between layers. Fascia is the covering of muscles, the envelope. The envelope of one muscle gets stuck on the envelope of another muscle. So we're ordering the connective tissue or the web. And one of our keys is the movement. And the clasp in these are the kind of places that I'm working on right now where doctor sees them from across the room. She'll say, now back there on the back by the fourth rib, go in there and get that. And there it is."
From the 1974 Open Universe class, the same picture in tactile language:
What the model could not yet explain
Asher was honest about what the tensegrity model could not yet account for. The lower leg in particular gave him trouble. The tibia and fibula are essentially vertical and roughly parallel; if you set them up vertically and put weight on top, the bones can carry the load directly in compression, which makes the rest of the surrounding tensional structure look superfluous. This was the awkward case for a strict tensegrity hypothesis. Asher's working answer — and it was an honest one — was that the bones of the lower leg are only vertical for a small fraction of the time a moving human is actually walking; most of the time, the legs are angled, swinging, loaded eccentrically, and in those positions the tensegrity argument holds. But he acknowledged the difficulty as a difficulty.
"Of course with the scapula, you can't see from the shape of the bone anyway. It's so complex. See, now again, my hypothesis and it's strictly a working hypothesis has been that any given bone in the body represents compression lines. Now that's a wild hypothesis, mean it's a difficult hypothesis really to work with because then you think well a rib, curve that's coming around, well how can that represent the compression part exactly? That's a toughie. There's also the problem of the limbs and of the leg. Now, see one argument which I've had to try to deal with is that see, in the bones of the lower leg, they are apparently vertical, straight up and down. So therefore, they're not a tensegrity structure because if you put this thing straight up and down and put weight on top of it here, So the rest of it is in a way is rendered superfluous. Now I don't I don't know exactly what to say about that yet. Although, of course, in a moving human being, they are vertical only a very small part of the time. And the rest of the time, they're all like this. But they're also not resting on the ground. That's right. They're on a sprung arch. They're also not truly vertical if they come in like that."
Asher works through the awkward case of the lower leg:
Another piece of the model that remained provisional was the question of how the spine actually became a tensegrity in the developmental sequence — how an animal spine, structured for horizontal suspension, reorganized itself into an upright tensional mast during human evolution and during individual development. Ida pressed Asher on this and he had no full answer. The progression from suspension bridge to cantilever to tensegrity was a description; it was not yet a mechanism. The practitioners in the room recognized this honestly. The model was a working hypothesis, not a finished theory, and they treated it as such.
"I'm always in this thing arguing from coherence rather than from evidence at this point and I want to go and find the evidence for it to see whether or not it will work out like that correctly. Now, how are you going to get to that tensegrity mass, that upright of the human from the horizontal of the animal? Have you given any consideration to this?"
Ida presses Asher on the developmental question:
Coda: bones as spacers, the body as relationship
By the time Ida had absorbed the tensegrity model into her teaching, it functioned for her less as a discovery than as a confirmation of what she had been claiming since the late 1950s — that structure is relationship, that the soft tissue is the organ of structure, that bones do not hold the body up but are held in place by the surrounding web. Asher's icosahedron and shock-absorber arithmetic gave her doctrine an engineering vocabulary; Buckminster Fuller's geodesic principles gave it a cultural reference point students could recognize. But the underlying claim was the one she had been making all along. Structure is the relationship of parts in space, and the parts are held in their relationships not by stacking but by balance.
"Now realize that you cannot get balance except you relate that physical material body into a gravitational field. This is what we offer you that none of the more classical systems of manipulation have ever offered. None of these older systems have ever taken into consideration that you cannot get so called posture except as you have structure. Structure is relationship. It's relationship wherever you use the word structure, you are really talking about a relationship. You talk about this beautiful structure, you are talking about the way the top relates the middle, relates to the floor, the shape of the ground. All of this is implied when I say, I was in a beautiful structure tonight. Structure, wherever you use it, is relationship, and it is particularly relationship of parts in a body. This constitutes structure. Now posture is something else again. And the boys that devised the word posture knew what that something else was because the word posture means it has been placed."
In the Topanga public lecture, Ida states the doctrine in its final form:
The tensegrity model never received the formal scientific working-out that Asher hoped for. The literature he was trying to find at UCLA never quite materialized in his lifetime; the connections he had hoped to make with Fuller's circle in Houston never produced the technical paper that would have settled the spine-as-tensegrity question. What did survive was the working vocabulary — fiddling with the strings, bones as spacers, the body as a tensional web rather than a stack of plates — and the disposition it produced in practitioners trained in Ida's later classes. They worked with the assumption that a local intervention would propagate through a whole tensional system, that bones would float into their places when the surrounding web was balanced, and that the standard compression model described the failure case rather than the working one. That assumption, more than any finished theory, was Ida's tensegrity inheritance.
See also: See also: Ida Rolf on the August 5, 1974 IPR lecture discussing the spine as a unified structure rather than a series of bony segments — a related strand of the same argument from the year before Boulder. 74_8-05A ▸
See also: See also: 1975 Boulder discussion of cylindrical fascial structures within the thorax (Pat Kloth's model) as an alternative geometrical picture practitioners were considering alongside tensegrity in the same period. B4T5SB ▸