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L i s te n to T h e A B M P Po d c a s t a t a b m m /p o d c a s t s o r w h e reve r yo u a cce s s yo u r favo r i te p o d c a s t s 75 supinate, undulate, and dance through all the motions of this incredible bone structure. The coefficient of friction of the wrist, the dynamic ability for your carpal bones to slide relative to each other, is 0.05. By comparison, the coefficient of ice on ice is 0.04. In order to allow the wrist bones to hold up under load, the coefficient of friction would have to increase to 1.0. They would have to functionally fuse—think of sandpaper trying to glide on sandpaper. That's not going to budge an inch, let alone a centimeter. The problem is that the forces required to achieve this stability would tear your arm muscles, crush your carpal bones, and exhaust the energy of the system. And biological systems operate in ways to conserve energy as much as possible. Why? Because, evolutionarily speaking, you never know when your next meal is coming. Clearly, something else must be at work here, and Borelli realized it. His calculations of spinal biomechanics, incredibly accurate even by today's standards, showed that spinal muscles alone were not sufficient to support the spine when carrying a heavy weight. For his calculations, he imagined carrying a 120-pound trunk. From this, he surmised that the intervertebral disks must be of a viscoelastic nature, acting as both cushions and springs for the spine. From what we now understand about fascia, we know this is accurate. But there's still something else at work. And that something is tensegrity. TENSEGRITY IN THE BODY Coming from the worlds of art and architecture, not anatomy and physiology, tensegrity is a combination of the words "tensional" and "integrity" and refers to an object whose fundamental structure is composed of discontinuous compression members held in place by a contiguous tensional matrix. So, the traditional beams, columns, braces, and such that support and shape your treatment room or your house are still there, but they never actually touch. In the case of something like a geodesic dome, they are semi-f lexibly held in place by a taut, interwoven wire (Image). This gives these structures remarkable resiliency. If a tree falls on your house, it's going to do some structural damage. How much depends on what kind of roof you have and its condition. Whether you have brick, stone, wood, or aluminum siding exterior walls will also make a difference. If a tree falls on a geodesic dome, the dome will absorb the shock, distributing the strain throughout the structure. In doing so, it will "bounce back" against that stress and remain stable to the degree it was designed to do. Any increase in compressive tension will distribute that tension throughout the structure. Sound familiar? It did to Donald Ingber, MD, PhD, when he was an undergraduate student taking a course in sculpture. Currently, Ingber heads the Wyss Institute for Biologically Inspired Engineering. But back in the mid-1970s, he was making small tensegrity models in his art class. He was fascinated that when he pressed down on them with his hand, compressing them, they f lattened. When he removed his hand, they sprang back to their original shape. This reminded him of how living cells, when placed on a rigid surface, spread out and f latten. When placed on a f lexible piece of rubber, the cells contract and become more spherical. This led him to wonder: What if cells are actually tensegrity structures? Using a series of experiments, Ingber showed that the cross-linked filaments of the cytoskeleton (see Massage & Bodywork January/February 2023, page 78) behaved exactly like a tensegrity structure. Even though individual cells are surrounded and permeated with f luids and membranes, there is a network of molecular struts and cables that stabilizes the shape of the cell. TAKEAWAY: Giovanni Alfonso Borelli's calculations of spinal biomechanics showed that spinal muscles alone were not suffi cient to support the spine when carrying a heavy weight. ABMP CE COURSE: "FASCIA FUNDAMENTALS: WHAT EVERY MT NEEDS TO KNOW" 1. Open your camera 2. Scan the code 3. Tap on notification 4. Learn!

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