Notes on Anatomy and Physiology: Getting the Feel of Tensegrity

We’ve spoken recently of how the body makes use of tensegrity to help hold itself together. We stretch out our soft tissues and they resist further expansion and create a sea of continuous tension that tugs on and supports the bones suspended within it. Soft tissue and bone working together.

Because the soft tissues resist further expansion, they supply an ever-present, wall-to-wall, continuous pull inward on the bones. The bones, by refusing further compression, push outward locally on the soft tissues surrounding them and prevent our structure from collapsing in on itself. We create a form that is less stiff, more resilient than one relying on continuous compression.

Thinking of the body’s architecture this way leads us to view the elastic, distensible elements of the body in a new light.

If we use the word “tendon” to mean any soft, elastic tissue that contributes to a web of continuous tension, we begin to see many structures of the body as tendon: the lungs that want to spring back once filled; the diaphragm, esophagus, stomach and intestine; the aorta, the great artery that leads freshly oxygenated blood out of the heart to all corners of the body; the veins, lymph channels and nerves, supplied as they are with walls that contain elastic connective tissue; the ligaments and capsule that surround each joint; the muscles and skin and the wrappings of the brain and spinal cord.

All are capable of elastic recoil. All are connected with one another. And all are prone to the ill effects of aging and disuse, and must regularly go through a full range of motion to maintain elasticity and avoid desiccation.

Building a tensegrity structure quickly give us a feel, an intuitive sense, of how the body works in this way. Taking the time to construct an icosahedron is well worth the effort.

Fig 1 A tensegrity model in its simplest form - the icosahedron, a geometric figure with 20 sides

What follows is a summary of the instructions for building such a model provided by Thomas Myers in his book, Anatomy Trains, second edition:

  1. Collect 6 dowels (I used 3/8 inch dowels, each 12 inches long), small screws (12, one for each dowel end) and 24 elastics (Universal Rubber Bands, size 31, 2-1/2 x 1/8 x 1/32 inches, order #00431, worked well for me). When placing the screws in the dowel ends, leave enough shaft visible so that 4 rubber bands may be slipped under the head of each screw. Have another pair of hands available to help with the assembly.
  2. Take  2 dowels. While holding them vertically and parallel to one another, place a third dowel horizontally between them near the top to form the letter “T”. Connect rubber bands from each of the upper ends of the 2 verticals to each end of the horizontal dowel, using 4 elastics in all.
  3. Turn the vertical dowels upside down (180 degrees) so that the horizontal dowel now lies on the table. Repeat step 2, attaching 4 elastics from these ends of the uprights to the ends of a new horizontal dowel. You have now formed the capital letter “I”.  See fig 2A below.
  4. Turn the structure 90 degrees so that the 2 horizontal dowels are now upright, creating an “H” with two crossbars. Make sure those extra set of hands are close by as the next few steps are a bit more difficult. Place a fifth dowel horizontally between the 2 uprights so that this fifth dowel is at right angles to all the others and pointing toward and away from you. Connect the 2 uprights to the ends of the new horizontal dowel. Maintain a sense of humour as elastics fly unexpectedly into the air.
  5. Turn the structure over and repeat step 4, employing the sixth and last dowel. See figure 2B below.
  6. Finish by adding the remainder of the elastics, connecting each dowel end to all four adjacent ends, except for the ends of the dowel that is parallel to it. The resulting structure will stand alone, more or less balanced and symmetric, with 3 sets of parallel pairs of dowels. Each dowel end will have 4 elastics running out from it to the other ends nearby while remaining unconnected to its parallel partner. You may need to take an extra turn or two about some of the screws to even out the tension and improve the symmetry.

Figs 2A and 2B Stages in building an icosahedron Meyers, page 49

If the elastics are excessively long, the tendons of the model will be too lax to provide adequate structure. If unduly short, the tight tendons will make it difficult for the structure to alter its shape with changing stresses. Both these situations mirror what happens in the practice hall when our soft tissues are too loose or too tight.

As you play with the model, you appreciate that the rubber bands form a continuous web while the dowels fail to touch one another. Continuous tension, discontinuous compression. Alter a single elastic or dowel and the whole structure responds. Draw two parallel dowels apart and the whole structure expands in all directions – recreating much of the feeling of density, fullness or stickiness that comes with balanced movement and was mentioned in the last note. Push two parallel dowels together and the entire structure contracts.

A complete structure expanding and contracting. Breathing in and breathing out.

Reflections about the body begin to surface:

  • does the spine really function as a continuous compression structure? Or do the 24 vertebrae perch precariously one on top of the other, only kept in place by a fabric of soft tissue?
  • soft tissue forces contribute greatly to our shape, our posture. By altering those forces, we alter our shape
  • Taoist Tai Chi™ internal arts of health work to create a balance of tension forces within all our soft tissues so that we may move with poise and ease
  • tensegrity is one way the body manages potentially injurious loads, distributing, rather than localizing, forces that act on it
  • the soft tissues (muscle, tendon, ligament, fascia) are always under some tension. In this way that they contribute to structure. In the cadaver, for instance, sever the anterior and posterior longitudinal ligaments and the ligamentum flavum, leave only the intervertebral discs to hold the vertebral bodies together, and the vertebral column expands
  • the angle between elements of an icosahedron is 60 degrees, the same angle taken by the alternating layers of the annulus fibrosus
  • Stephen Levin, an orthopedic surgeon, believes that the bony components of the human tensegrity system “kiss” but are not in compressive opposition with one another. He describes how, during a surgical procedure on a living subject, the articular surfaces of the joints of the knee, ankle, and elbow cannot be forced into contact with one another as long as the surrounding ligaments remain intact. This view is debated by others and runs counter to our usual way of thinking about how the bones stack to transmit weight down through the body. In life, the body likely moves through a continuum between continuous compression and full tensegrity, utilizing different strategies in different circumstances and at different times. What is clear is that our elastic soft tissue, not just our bones, contribute greatly to structure and to our ability to alter shape and move about
  • the shoulder blade doesn’t sit on top of anything. Rather, it hangs off the rib cage, floating in a tension network created by the surrounding muscles and tendons of the shoulder girdle. Much like the hub of a bicycle wheel is suspended in a tension network of spokes.

Fig 3 One way of explaining how compression loads from the arm and shoulder are transferred to the axial skeleton via the soft tissues. The right shoulder blade is seen lying along the back wall of the rib cage, floating in the tension network created by the muscles and tendons of the shoulder girdle - much like the hub of a bicycle wheel is suspended in its tension web of spokes. The head of the right arm bone (the humerus) articulates with the triangular shoulder blade. The rings are the upper 4 ribs connecting the first four thoracic vertebrae at the back with the upper and mid sternum in front. The right clavicle runs from a point on the scapula to the sternum lying in the midline of the body. Stephen Levin, 2003

Fig 4 A wire-spoked bicycle wheel. The hub (like the shoulder blade) is suspended in a network of tension created by the spokes. The combined weight of the bicycle and rider (compressive load) is applied to the hub and then transferred evenly around the circumference of the rim solely through tension of the spokes. The compression members (hub and rim) do not touch. Stephen Levin, 2003

1. Anatomy Trains, Second Edition, 2009, Thomas W. Myers, Churchill Livingston Elsevier, ISBN: 978-0-443-10283-7

2. Dr. Stephen M. Levin, orthopedic surgeon

Bruce McFarlane, MD

© Taoist Tai Chi Society of Canada 2010



Filed under Anatomy and Physiology, Health Watch

7 responses to “Notes on Anatomy and Physiology: Getting the Feel of Tensegrity

  1. Cliff Yerex

    Dear Dr. McFarlane,
    The icosahedrons remind me of pieces of the ancient poem about taijiquan: “Let the postures be without holes, hollows, projections, or discontinuities and continuities of form.”

    If we muscle our movements (perhaps a hole in the tensegrity), or misplace our feet or tiger’s mouth (perhaps a projection), any or all of the imperfections in our own “forms” will appear.

    If we allow or even set up the form to take shape the tensegrity connects, to lesser or greater degrees, all the parts of our form, like the icosahedrons: “In motion, all the parts of the body must be light, nimble and strung together.” Direction and intention come to mind in this.

    Remarkable correlations for me between your articles and the ancient poem; thanks again!
    Cliff Yerex,

  2. Jo Mortimer

    I recently experienced these ideas in my own body for the first time during a 5-day Taoist Tai Chi™ workshop in Lodz, Poland.

    I have had a mild curve in my spine since being a teenager, probably as a result of carrying a heavy bag over one shoulder daily when at school. This spinal curve resulted in my left shoulder being slightly higher than my right. I am now 29 years old and the condition has never bothered me. Others occasionally pointed it out, but I felt it was only a mild cosmetic ‘defect’, and one I could easily live with!

    Because this condition was to do with ‘bone structure’, I assumed it was permanent. I was also unaware of it in terms of proprioceptive feedback, and could only see it when looking in the mirror.

    At this workshop one of the instructors drew my attention to my uneven shoulders. She said:

    “It is not forever, but you will have to work hard”.

    As my brow furrowed she added with a smile, “but it will be easier if you relax”.

    Through regular practice I now have a much better feeling of where my collar bone is, and have learned to hold myself in a more balanced way. I have allowed my ‘tendons’ to change. This requires less energy and is more sustainable – I hopefully have many years of standing and sitting to go, so am pleased to have found an easier way to go about it!

    It is an empowering experience to change one’s own body at an internal level.

    Huge thanks to everyone involved in the Taoist Tai Chi™ Society for making these opportunities possible.

  3. You write about tensegrity and its role in human anatomy very well; I shamelessly re-blogged your previous post in admiration. Keep it up! Post some pictures of your tensegrity model, if you have time.

  4. Chris Hubbard

    Thank you for this! A couple of notes on construction: if you have Tinker Toys in your home, they make great sticks for this, since they are pre-cut to standard sizes, and have slots in the end which will hold the rubber bands. I also found that in step 4, the new sticks could be connected to the existing bands, so that each band made a triangle. This uses fewer rubber bands, and negates the need for step 6.

    I have been enjoying all your posts, Dr. McFarlane, and look forward to your return after Awareness Day!

  5. Dave Mundt

    Greetings and Salutations…
    An interesting discussion of Tensegrity, and, well to the point. This concept, by the by, was first discovered by Richard Buckminster Fuller in the early part of the 20th century. He applied its principles to building structures with minimal materials, and, throughout his inventing life. By the by, he also invented the geodesic dome, and, Celotex….which is a basic insulating and building material in today’s world…
    It is well worth exploring some of his other ideas and concepts….
    dave mundt

  6. I’ve been working on applying tensegrity to yoga poses. My understanding so far is that muscles are the “tensioners” or “tuners” that we use to add tension to the fascial tissue of our body as required. That means muscles can be relaxed or active as required so long as the fascial tissue remains tensed.

    In the tai ji context, I’m guessing that the weight of our bones (the elbows in particular) can also be used to add tension to our body as required, particularly when they are allowed to “sink” down.

    How do we know when a part of our body doesn’t have positive? I think that one clue is looking for areas that have no feel. (And part of learning to feel the body is learning how to differentiate between muscular tension and the tension transmitted by lines of connective tissue)

    The really cool thing about tensegrity (to me at least) is that it offers a means of stabilizing the body with minimum effort but also a way of feeling the body. The more we relax muscles that aren’t needed the easier we can feel the pull along chains of connective tissue.

    I’m wondering though if there might be multiple tensegrities within our body at any time (perhaps like the spirals of DNA wrapping around each other?)
    This isn’t so relevant in tai ji because we are constantly moving in that art, but in yoga poses where there tends to be more emphasis on external stillness, I often teach my students to focus on making the parts of their body feel long while inhaling and then to relax while exhaling.

    I feel like the “making long” action engages tensegrity, but then what holds us up when we exhale?

    Or maybe the act of breathing (lengthening and then relaxing) is actually tensegrity in action?

  7. A Lyon

    With my experience comes a greater understanding of, and interest in, what is spoken of in the Anatomy and Physiology posts. Please write some more when you are able!

    Here’s what comes to my mind reading about all this at this stage in my practice and development:
    Our body parts in and of themselves are not going to collapse in on themselves because our material components by tensegrity to held to a certain shape (forearm, big toe, thigh), but we actively have to prevent the entire structure from collapsing down to the floor, going limp. We actively have to create a tension and rod with gravity whether sitting or standing, in order to fulfill the requirements for the balanced tensegrity that eases bodily movement and prevents pain. Between gravity and our heads we have to place the final rod in the model that makes it all work.

    Gravity works for us in so many ways–it creates the energy needed to return us to standing, as was described in Part 1 of the post on fascia-and also provides an invisible end for the tensile pull from our head. I’ve often had the visual of the foot-to-head connection being like a coat rack upon which the rest of my body hangs like a limp jacket. As long as my head stays up the rest below is free to relax. (like a marionette string, or the sky-hook sometimes mentioned)

    During my own practice I think of my body as having 5 points of active intention (head, hands and feet) and one passive point I never have to think about–gravity. Everything in between is in a state of relaxation following along and responding to the intended motions of those 5. With the proper balance of all these points and the timing and positioning we’ve been given in the movements of our tai chi the body is free to move according to the expansion and contraction of the tensegrity I create between body parts. My own experience and observation of others informs me that if too much intension is placed on any one or more of those five points to the exclusion of any other(s) then we look/feel weighted down on top, muscle through, and it hurts (me anyway)! I mentally struggle with myself in what “should” be easy movements. In addition, when intension is placed somewhere within those points, as when we turn or shift weight too soon, then tensegrity is broken (blockage occurs) and the body can no longer move as one. It no longer looks like it is breathing. [Watch Tony Kwon do don yus or tor yus–his body moves like a lung expanding and contracting in all directions at the same time constantly–all joints opening and closing in proportion to one another, no joints at rest waiting for others to “complete the move”.] Bruce says the cells have tensegrity, the body parts have tensegrity, but we have to activate the tensegrity of the whole structure with our intension to “stand all the way up” and “keep the chest up”.

    I just find this so fascinating and look forward to further discussions and understanding at future workshops and in reading blog posts. I especially liked in “…Facia Part 2” when Bruce mentions individuals having the opportunity to discover a new way to move in daily life at any age. Reminds me to tell myself “as in tai chi, so too in life”–what I learn from our tai chi chuan practice and my involvement in the Society can be applied to other areas of my life. My ‘tai chi life’ (“grand ultimate” life) is not just a physical one–there are invisible forces other than gravity that can throw me off balance if I don’t maintain and respect tensegrity and keep my intention (attention / awareness?) diversified. [I can hyper focus in a way that is harmful to myself. Oh, that’s what is meant by keep the gaze soft. Interesting.] I hope more people can make discoveries that ease their minds and bodies. It seems to bring me a real sense of mental calm not to mention added enthusiasm for my own practice (and less back discomfort).

    Thank you to everyone for sharing their understanding of what Master Moy taught.

    ps- Does the Society have an internal tensegrity, too, or is it more likely just synergy / interdependence of individual members? Tensegrity–we’re held apart by geographic location, yet pulled together by our interest in the taoist arts of health, or is it Master Moy? Hmm. There’s the kind of human tension that repels and the physical kind that binds. Language–there’s a reason we aren’t supposed to talk too much when teaching, words mean different things to different people even in the same language.

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