Dr. Rolf on many occasions has stated that in a balanced body, “gravity lifts the body up,” that the body is supported by gravity, not torn down by it. She has also said that in a balanced body “weight does not go through the bones;’ and that fascia, not bone, supports the weight. Moreover, when the body is balanced, the direction of the thrust of the weight is not down, but up. In short, in a properly balanced body, the soft tissue carries the weight not earthward but skyward.
Put this way, the metaphor is a vivid one. It suggests that our proper direction is toward the stars, and not toward the center of the earth. It suggests that when we, as it were, tune into gravity, specifically by achieving a balanced physical structure, we are positively supported by the force of gravity, lifted up by it, propelled upwards by it, rather than dragged down and deadened by it, as is usually the case. A powerful metaphor indeed.
This metaphor poses many questions. How shall we understand it? And how shall we articulate it? For on its face, it is paradoxical indeed. How, after all, is it possible for fascia, which is soft tissue, to support anything? By definition, “soft” seems to mean “yielding”, giving way to pressure; how can a something which yields support anything at all? And how can gravity, which is a downward force, lift something?
On the other hand, we all see over and over again precisely this phenomenon. We have all seen how bodies as we work on them expand and extend, how they go up toward the sky, how a unique and spontaneous lightness comes into the tissues. And we have seen how, when they stand up, rise up from our tables, there is an instantaneous lift within them. Knowing what we do of the force of gravity working on these bodies, this event seems best described as being “lifted up by gravity”. Yet, again, how is that possible? What, specifically, are the mechanical principles and the facts of anatomy which make this possible? This paper is an attempt to give a clear answer to these questions.
I. THE MECHANICS OF WEIGHT BEARING
If I were to give you a weight, say a two-inch steel ball, and ask you to find a way to support it in nine cases out of ten you would look for something resembling a solid column, which you would place underneath it. This would then be a case of a column bearing a weight. In the tenth case, if you were feeling tricky and ingenious, you might make a little sling of string, hang the ball in it, and tie the whole thing to a door frame. In this case, the weight is carried by the tensile strength of the string. It is also, of course, carried by the columns which make up the door frame.
In one case out of a hundred, you might do the following: you take a balloon, partially inflate it, lay it on the table, and then balance the ball on top of it, that is, in the cup formed in the top of the balloon by the weight of the ball. You would then have carried out the instruction, but you would have supported the ball neither by a column, nor by a single tensioned piece of material.
The example of the balloon warrants further reflection. How does it bear the weight of the ball? It bears the weight by virtue of the pressure differential between the gas outside the balloon and the gas inside it, and by virtue of the tensional integrity of the material making up the balloon: “tensional”, because the material of which the balloon is constructed is everywhere under tension; and “integrity”, because any given fiber of the material which makes up the balloon is held in place and supported by every other fiber. (When you stick a pin in a balloon you interrupt the tensional supporting network at the point where you stick the pin in, so that the tension in the fibers nearest the pin hole is too great for them to hold; they break, overly straining the next nearest fibers, which break; and the pattern repeats indefinitely.)
We have, then, three examples of weight bearing structures before us: (1) a column, which is under compression by the weight on top of it; (2) an arch, a compression structure, from which some weight is supported by a tensioned structure, namely a string; and (3) a balloon, a structure which supports weight by a pressure differential, as long as its structural integrity is maintained.
I should emphasize, here, that when we think of weight bearing structures, we tend to think of the column, under a compressive load. We are surrounded after all, by millions of examples of these structures: every house, and virtually every object in it, are columnar structures, bearing compressive loads. We do not usually think of tensional structures; they are relatively rare, and are frequently part of a compressive structure (e.g., the door frame and string, above); but we mainly fail to include them because they require a relatively sophisticated level of abstraction for their recognition. For it is not self evident that a tensional structure should be able to bear weight.
Now, which of these three examples before us is the best analogy (so far) for the human body? The unsophisticated will say that the columnar example is the best analogy: the bones of the legs are like the columns of a temple; they support the body above them as the columns support the roof. And on that bony structure is hung the soft tissue, the flesh. Or: the bones of the spinal column are like a horizontally sectioned column of marble (different of course; but structurally similar), with softer cushions (the disks) between the segments. And each segment supports the weight of all the segments and structures above itself. This point of view underlies literally every present day anatomy and k inesiology text. Yet, as I shall show below, the balloon is a better analogy for the structure of the human body than the simple compressive column.
There exists another class of structures which combine tension and compression in a way different from any of the examples above. They were discovered by Buckminster Fuller, who calls them Tensegrity structures. I refer you to Figure I for a simple example of these structures.
What is going on here? The two V-shaped struts are held fast by a wire sling. Points A and B are pulled toward one another by the tensioned wire between them; this forces the legs of the struts outward; yet they cannot move outward, because of the tensional restraints of the horizontal wires. In this way the whole forms a stable structure.
Note that if the structure is balanced on point 8, and a weight is placed on point A, the whole structure will bear the weight, even though the only vertical member of the structure is a wire. Note, too, that only the struts are under compression.
These simple structures can be stacked on top of each other, so as to form a tower. Figure 2 shows such a tower. Fuller calls them Tensegrity Masts.
Tensegrity masts reward intended contemplation. Note that the only verticals in the structure are tensional members, not compression members. Nevertheless, the whole structure is capable of bearing weight.
How does it work? The strut centers cannot get closer to one another because the horizontals and diagonals will not permit it; nor can they get farther from one another, because the verticals will not allow it. Thus the struts are held fast inside the tensional web. We can describe it in more general terms (Fuller’s) by saying that there are local islands of compression within a comprehensive tensional network. We can also describe the struts as “spacers” inside the tensional webbing. Or we can say: the struts hold the tensional web in place; and the web holds the struts in place. Together they form a stable structure.
The whole structure can stand on its own because it represents a series of vector equilibria, a vector being a force with a specific direction, and “equilibrium” meaning that the forces balance exactly so that they cancel each other out. If you look at the outer end of any of the struts, and figure out what the direction is of the resultant force when each of the tension wires or strings is pulled tight, you will see that the resultant force goes right along the strut. The struts meet at the center of the structure in such a manner that the force transmitted along any strut is exactly balanced by the force in the other three. The whole structure is stable because every force is balanced by an opposing force.
Consider now the “dynamics” of the mast, that is, what happens when one plays with the tensioning of the tensional network. (I realize that this is very hard to do as an abstract mental exercise. The best thing is to build one, and try out different tensionings.) Notice that not just any old tension will do: if the net is too loose, gravity simple collapses the struts into a heap on the floor. Why? Because there must be sufficient tention in the web to create the vector equilibria which the struts represent.
What happens if there is too much tension in isolated segments of the tensional web? Suppose, for example, that the tension in the verticals were greater than in the horizontals or diagonals. What would the effect be? The struts will tend to bend in toward the center line; and they will rotate to ease the strain. What will happen if there is too much tension in one of the verticals, say between points C and E in Figure 2? The structure will tend to bend over toward the side with too much tension, and it will rotate.
In sum, too great a tension anywhere in the structure causes shortening and rotations, though not necessarily in the area of too-great tension. Correcting bends and rotations, then, consists in easing off local tensions, so that the structure can assume its proper length and unwind its rotations. (Sound familiar?)
Notice, too, that the structure assumes its maximum height when it is properly tensioned, that is, when the tension is evenly balanced throughout the entire tension net. Getting the shape right, too, requires getting proper balance in the tensional net. One could say that when it is properly tensioned, the structure comes to its designed limits rather than to its accidental limits.
Let us now suppose that we replace the wires or strings of the Tensegrity mast with a single piece of translucent fabric, wrapped around the outside of the mast. The struts we connect as they were, only now the tensional members of the structure will be within the fabric, part of It, and not discrete entities as in Figure 2. One could imagine this as single threads within the fabric carrying the tension, instead of discrete strings, as before. And one can, of course, imagine the tension distributed throughout the fabric, rather than following distinct threads; we can achieve this by appropriate methods of weaving and fastening. Thus, in this thought experiment, we can get the structure to stand up, and to bear weight, just as before.
If we suppose that the fabric does not show the lines of tension, the method of support in the structure would be quite mysterious to the uninitiated; it might appear to be some fort of trick, For if we assume that someone shines a light through the structure, or X-rays it, what would he see? He would see a series of angular struts within a rectangular piece of sheeting. Yet the whole thing can stand of its own accord.
Let us suppose, further, that we were to place spongy pieces of plastic vertically between the centers where the struts meet, to act as shock absorbers for vertical stresses which are placed on the whole structure from time to time. Because they are shock absorbers, we place them only loosely between the strut centers; they only bear a load when the whole structure bears a load. Let’s suppose, now, that someone were to take the whole structure apart, dissect it, in an effort to understand how it works. He would find its plastic shock absorbers, its struts, and its sheeting. He would conclude, naturally enough, that what held the structure up is the combination of the struts and the spongy plastic, that the spongy plastic is the main structural element of the mast, and that the function of the struts is merely to hold the fabric out to the side. But he would be wrong; not, however, because he fails to find or to see something, but because the models he has before his mind do not allow him to understand what is before his eyes.
We see and understand what our categories allow us to understand and see.
We have, then, four models of weight bearing structures before us: the column, the arch and the sling, the balloon, and the Tensegrity mast. If we examine each model carefully, we will find that all contain a balance between compression and tension. The column, the paradigm of compression, is under tension around its middle; when it is compressed! from above, it resists the tendency to squash. And the balloon represents a balance between the compression of the gass within it, and the tension in the fabric of the balloon. The interesting question, then, is, Which is uppermost? In the column, compression is uppermost-at “high tide”, in Fuller’s phrase. In the balloon, tension is uppermost. And in the Tensegrity mast, they are, one might say, half and half.
Now, once more, which of these models is the best analogy for the structure of the human body, The Tensegrity mast, clearly. Why? Because the dynamics of the body are much more closely analogous to those of the Tensegrity mast, than to any of the others. (You can see, now, why I said earlier that the balloon is a better analogy for the body than is the column; for the body behaves more like a tensional structure than a compressional structure.)
II. SOME EMPIRICAL AND ANATOMICAL CONSIDERATIONS
Both rolf and Alexander practitioners have noted time and again that the human spine can, under certain circumstances, extend, that is lengthen vertically. And we all know that the people we work on get longer. Consider, too, the phenomenon which occurs at the end of a well done series of 10 hours: if you sit the rolfee on the floor, on his ischial tuberosities, and gently wiggle his head from side to side, you can feel his spine wave downwards, so that his sacrum is like a weight on the end of a line.
I take these two facts to be major pieces of evidence for considering the structure of the human body to be correctly understood on the model of Fuller’s Tensegrity structures. For what alternative models are there which will satisfactorily explain these phenomena?
I can put the argument this way: either the spine is a column, or it is not. Consider each alternative in turn.
If the spine is a column, then, like all columns, any arbitrarily selected plane through it will be compressed by all the weight above that plane. Consider a stack of plates. Any given plate will be compressed by the weight of all the plates above it, and moving any lower plate will be more difficult than moving a plate higher up in the column. Similarly, moving a lumbar vertebra will be more difficult than moving a cervical or thoracic vertebra. But, as above, when one waves the sacrum on the end of the spine like a sinker on a fish line, one is moving the lumbar vertebra laterally as easily as one moves the cervical vertebra. Therefore the assumption that the spine is a column, resembling a series of stacked plates, must be somehow wrong.
If the spine is a column, moreover, then the forces exerted on the lower lumbers during weight lifting become terrific. Assuming that the spine is a column, some scientists have calculated that a 170 pound man lifting a 200 pound weight must develop at least a 2071 pound reaction at the Jumbo sacral disk. Anatomical investigations show, however, that the crush strength of the lumbar vertebra, that is, the amount of weight which when placed on the bone will crush it, is no more than 1800 to 2000 pounds. Yet in weight lifting salons all over the world, 170 pound men consistently lift over 200 pounds, without crushing their vertebra. Investigators in this area examine the spine closely, therefore, looking for additional support mechanisms for the spine. What they fail to examine is the original assumption that the spine functions as a column.
Why do they not question that assumption? The main reason, I believe, is that they do not have our experience of the extensional capacities of the human body.
Let us now consider the idea that the spine is not a column. Yet if the spine is not a column, then what is it? Let us try: it is a series of compressional spacers within a tensional network. Such an idea now makes sense, because we have before us, in the previous section, just such a structure, the Tensegrity mast.
Now, if the spine were like a Tensegrity mast (note: like a Tensegrity mast, analogous to it; not: the spine is a Tensegrity mast; we do not know that), then how would we expect it to behave? We would not expect that each segment of the spine would be under a vertical compression from the weight of the structures above, for as in a Tensegrity mast, what supports the weight of the structure is the entire tensional network balanced by the compression in the bones. We would expect, therefore, that in a balanced body the lower vertebra would move relative to its neighbors as easily as would the upper vertebra. This is what we find when we wave the spine of the tenth hour rolfee.
We would also expect that, as we get the tensions in the fascia progressively closer to their proper values, the body would tend to lengthen. Why? Because, on this model, a body is unbalanced because its tensions are unbalanced, and because the tensional members are out of position – that is why the segments of the body do not line up correctly around a vertical line. And gravity grabs the unbalanced weight masses, pulling them differentially toward the ground, at which time the imbalances feed upon themselves. The body ties itself up, trying to prevent its ultimate collapse. On this model, the body is shorter when it is tensionally unbalanced than when it is balanced. So when we bring tissue toward its normal position, and as we lengthen and untie the fascia of the body, we are changing the tensions in the tensional network, and bringing them toward normal. The body therefore expands and extends towards its designed limits.
(Notice that I am using two senses of “balance”: vertical weight-mass balance, as in a stack of children’s blocks, or a vertically balanced string of pearls; and tensional balance -which is not directly observable. Where tensions are in equilibrium. I am suggesting that, in a human body, vertical weight-mass imbalance is a function of tensional imbalance, and conversely: vertical balance is a function of tensional balance.)
So far, my argument has been circular: I have fit limited data to a theory, and found that the theory explains the data. The crucial question is, “Does the theory afford us any predictive power?’ I think it does, and of two sorts: we should expect that with our work, new sorts of control should become available to the body; and we should be able to find anatomical evidence for the theory.
First, the anatomical evidence: is there any? One lack we all face, of course, is the absence of comprehensive investigations of the fascial networks of the body. But even assuming we had these details, would they show that the structure of the human body is an analog to Fuller’s Tensegrity structures?
The final answer to this question must wait, I am afraid, upon a mathematical analysis of the fascial networks of the body. We have, of course, begun that analysis. What we are attempting to discover is whether we can create a computer model of Tensegrity structures in which the tensional network is curved in space. Fuller’s structures deal with planes and lines in space. We must then get a closer and closer fit between our models and the actual anatomical structure of the human body. Thus far, we have found nothing which precludes understanding the body this way. (If this works out, we will have provided Structural Integration with a mathematical basis.)
Second, the new controls for the body. If one meditates on drawings of the intrinsics of the spine, one must consider the question, what are these very small muscles supposed to do ? To answer this question, reflect upon the nature of muscle: that it is contractile tissue, designed to exercise a pulling force between two points. Now, we tend to think always of muscles as acting on bones; that the principal function of muscles is to move bones. But consider now that the first result of a muscle fiber contracting is to introduce tension between two points in space. If a bone moves, that is then a reaction to that tension. If bones do not move, on the other hand, then the contraction of a muscle fiber will put a greater tension into the tissue than existed before. And now we have a way of understanding what the function of such an increase of tension might be: to support the structure as a whole. Therefore, (though we do not know this) one function of the intrinsics might be: to adjust the tensions of the fascial network, in response to varying loads placed on the spinal structure as a whole, by the activities of the shoulder girdle, for example. And if we dwell upon this image for awhile, then we can say: muscle pulls on muscle, and bones follow.
We can also say that the structure as a whole has the capacity to bend precisely because it has the capacity to vary the tensions within the tensional network. On this model, the bones, being spacers, then follow, in their spacer, compressional capacity, the activities of the tensional network. One could say: it appears as though the muscles act on the bones: but the reality is that the muscles act on soft tissue.
Our anatomy books, then, can easily mislead us. For they tell us that a muscle arises on this bone, and inserts on that one. The natural inference, then, is that the function of muscles is to pull bones toward one another; and indeed, that is the viewpoint of our books. But we can now see that that point of view is highly misleading, even wrong.
What we need to see and understand, therefore, is how muscles attach to other muscles, and how one muscle structure continues into another. (We can see the body as a conglomerate of many muscles – the point of view of anatomy texts. We can also see it as the differentiation, division, of a few muscles, or of one a gestalt figure-ground reversal.) Thus, for example, we need to see the rectus femoris not only as arising at the anterior superior spine, and attaching on the tibia; we need also to see it as arising at the complex junction of the external oblique, the internal oblique, and the transversus, and as inserting into the tibialis anterior and exterior group. (These junctions are, of course, more complex than this, and I ignore fascial connections in this illustration.)
All of this implies a drastically different conception of the structure of the human body from the conventional one, which says that the bones are the principal structural elements of the body, on which is hung the soft tissue. But now we can say: the soft tissues are the principal structural elements of the body, and the bones deal with local compression forces within local segments of the structure, so as to stop the soft tissue from collapsing in on itself. In a correctly balanced body, then, the bones will float within the soft tissue. This is clearly and strikingly apparent when it happens.
What overall picture of the structure and function of the human body does the tensegrity mast give us? For myself, it is this: in the balanced body, the soft tissue network of the body suspends each bone in precisely that position where it will deal with the compressions created by the tensions of standing and of movement. Each bone will be suspended within its own supporting network, and will depend for its support in the gravity field not on the bone below it, but on the soft tissue around it and distant from it. Thus each bone of the body will be separate from every other, and separable from it; the soft tissue will carry the weight of the body across the joints, and the bones of the joints will not bear compression loads simply from the weight of the body.
Thus each bone of the cranium will float separately from every other bone, and they will articulate with each other. Cranial osteopathy confirms this result. Each vertebra of the spinal column rest within the soft tissue network, and not on the disk and vertebra below it. The sacrum will articulate within the iliac bones, since it too is not weighted down by the bones and structures above it. The shoulder and pelvic girdles will similarly float within the soft tissue, as will the bones of the extremities. The body, therefore, is a soft tissue entity, with local bony spacers, rather than a hard tissue entity, with soft tissue motor units.
What is the function of the vertebral bodies and intervertebral disks in this conception of the body? For they look obviously to be weight bearing members of the body. I believe that they are the shock absorber system of the upper body; they are designed to absorb vertical loads placed on the body by its activities. They also function in the unbalanced body as the principal weight bearing mechanism of the body. That, in my opinion, is why so many people suffer from ruptured disks, etc.: they are using their shock absorbers as weight bearers. Think what would happen to an automobile whose springs were so weak that all the weight of the car was placed on the shock absorbers; they would do the job for a while; but they would eventually fail. So, too with the disks of the spine. Consequently, on this conception of the body, all the miseries of disk herniation, etc., are preventable, simply by so ording the body that the soft tissue bears the weight of the body, and not the bones. Our work does, of course, precisely that.
This conception of the body implies, too, that bone joint compression diseases, such as arthritis, are preventable by the simple expedient of so re-organizing the body that the weight is taken off the bones of the joints and put into the soft tissues of the body. Since tensile strength per unit of cross sectional area is much greater than compression strength per unit of cross sectional area, this transformation will result in much greater efficiency for the body as well. One could say that our work consists in evoking the tensegrity weight bearing system of the body, and of retiring the compression system of weight bearing to its proper role of shock absorber.
Movement, then, in a balanced body is quite different from movement in an unbalanced, random body. An unbalanced body will tend to look as though it really is using its bones to get around, so that the person is, so to speak, pole vaulting around on his leg bones. Movement in a balanced body, on the other hand, will look liquid, flowing as, indeed, one should expect of soft tissue which contains water. (I do not mean that it looks watery.)
The mechanics of motion need, then, to be entirely re-thought for the balanced body. Conventional kinesiology has it; for example, that the principal lateral abductor of the arm is the deltoid muscle, originating on the scapular and clavicular bony surfaces, inserting on the shaft of the humerus, and acting as the power unit of a lever system; the fulcrum is the head of the humerus in the glenoid cavity, the load is the rest of the arm, and the point of leverage is the deltoid’s insertion on the shaft of the humerus. Yet, in a balanced body, the arm does not function like that at all. Since on our hypothesis it is a soft tissue structure, we should expect that the soft tissue will carry the arm outwards, with the bone in it, by a process of soft tissue extention rather than by a process of hard tissue leverage. And, indeed, this is exactly what we see when the shoulder, elbow and wrist joints are functioning correctly. The problem this sets us, then, is how to describe it in mechanistic terms.
The image of human movement which this model of the structure and function of the human body produces, then, is one of liquid, flowing movement, with the bones acting as spacers within the soft tissue – precisely the image which Dr. Rolf has urged upon us so many times.
III. HOW GRAVITY SUPPORTS THE BODY
That gravity, a force which draws everything toward the center of the earth, should support something, lift it up, seems wildly paradoxical. For how can a force which acts in one direction make something go in the other direction? (Newton’s Third law won’t help here.) Yet to sharpen the paradox, we all of us see it happen every day, and we experience it when we put ourselves as close as possible to the vertical. So how is this event possible?
Let me emphasize again that if we approach this question with a simple compressional, columnar model in mind, we cannot answer it. For such structures just do not behave this way. Yet the phenominon of gravitation as support does occur; therefore we must look to other models.
What we know of Tensegrity structures allows us to give an easy answer to this central question. Gravity supports a (human) body by setting the tensions correctly in the tensional networks.
In the upright human being, most of the muscle mass of the body is in more or less vertical alignment. When a human being stands up, then, the force of gravity puts a certain tension into the soft tissue network, simple by pulling on the mass of the muscles. Note that like all cells, muscle fibers are mostly water, which is relatively heavy; and that each muscle is an aggregate of thousands of muscle fibers, which are themselves like long skinny tubes of very thin fascia, filled with a contractile mechanism. Muscles act as units because the fascia of each little muscle cell is interwoven with the fascia of all the rest. When gravity pulls on the muscle, then, it sets an even tension throughout the muscle, and through it into the planes of fascia of which the muscle is a part. Gravity creates tension in the tensional network of the body, therefore, without the body doing anything, specifically without the body contracting anything.
With these considerations in mind, I offer the following hypothesis: when a human being as all his different segments lined up along a vertical line, then the tensions in the tensional networks of the body, the fascia, are set to such a. level by gravity, that the structure stands up by itself, and reaches its maximum extension. A shorter way of saying this is to say that gravity supports the body by setting the correct tensions within the upright man. An even shorter way of saying this is to say that gravity supports the body, lifts it up.
In advancing this hypothesis, I am ignoring the phenomenon of muscle tone: for we all know that if a muscle is denervated, it at once loses the resilience and life we expect of it, and becomes flabby and slack, and eventually disappears, What then is the function of muscle tone?
The topic is complex. At this point, I shall say only that muscle tone is one of the forces which puts tension into the tensional networks of the body, the other one being gravity. And that tone itself serves two functions: to tension two or more points in space; and to put lateral horizontal tensions into the tissue. If one meditates on cross-sectional anatomy texts, and imagines what happens to the tissues he sees drawn there when the muscles what happens to the tissues he sees drawn there when the muscles contract, then he will see that the muscles not only shorten, they also expand. And when they do so, they put lateral, horizontal tensions into the fascia) networks. (Muscles are like water-filled, sausage-shaped balloons: if you bring the ends of the balloons closer together, the water must go somewhere; and so it swells the middle of the balloon outwards.) And I believe that this has a great deal to do with the horizontals created by our work.
I should like to add a cautionary note. I am not denying that the legs are like columns under the body. What I am denying is that the bones of the legs are columns within the legs, and that they are the principal elements, structurally speaking, of the leg. I issue this disclaimer, because it is easy to confuse the two. The leg is a column, under an erect man: it supports the weight above it. But it is not a simple columnar compressive structure, like the column of a temple. And in movement, it isn’t like that at all.
In sum, then: the leg itself is a weight bearing structure; the bones are not, though they do bear compressive loads, and that load is part of the weight bearing structure. The weight bearing structure is the tensional compressional balance, which, of course, is all inside the body, and cannot be directly seen.
I should also like to add that this conception of the body makes simple sense out of our work. For our lengthening procedures are then simply part of our over-all decompressing activities. And what we do is to allow the segments of the body to float up and off the segments below. (Such a statement makes no sense, of course, if you view it in simple compressional terms.) The natural tendency of a body, then, is upwards. One could say: we are trying to get people to stop functioning as though their structures were columnar compressive structures; and are trying to get them to allow themselves to float in the gravity field, as is their birthright.
We are, therefore, closer to midwives than to sculptors; we are aides at the birth of physically mature human beings.
La Jolla, California
February 7, 1975