The oft-cited example of tensegrity is the functioning of a sailboat’s mast (Diagram 11-22) as it supports and bears the weight of its sails. However, it is not the mast’s sturdiness that holds the sails upright and thereby resists the tremendous force of wind acting on the sails. Instead, the principle of tensegrity describes how this kind of structural support can be explained in terms of the mast's interaction with flexible elements, such as the boat’s stays (forestay, backstay, and shrouds). Together, they create an effective system to spread out, and cooperatively share, the force acting against the structure.
Applied to the human body, tensegrity explains how the spine, via “soft tissue” fascia elements, such as ligaments and tendons, work in concert with hard strut elements (bones) of the skeleton. These allow the body to bear weight and yet maintain a fluid interaction with gravity. The synchrony between these two types of interacting support mechanisms –– flexible and rigid–– is important for three reasons. First, in terms of structural support, the fascia function as guy lines; in the body’s myofascial system, stress received through fascial elements provides an overall piezoelectric response. Piezoelectric has to do with the way certain structures in the body, such as fascia, tendons, and bones, much like crystals, generate an electrical charge when they are stimulated by pressure or stress. This function not only contributes to the body's measurable bioenergetic field, but, as will be discussed later, also provides more clues to the nature of the body's “energy” system. [i]
Second, the tensegrity model helps describe the body’s ability to heal structural injuries when proper alignment displaces extreme stress or trauma away from a concentrated area, such as the spine. This synchronic interaction allows the body to function as an integrated support-healing system. Third, the principle applies to more advanced athletic abilities, as the athlete who fully realizes the potential of the tensegruous structure is then able to engage increasingly subtle levels of interconnected and highly refined force.
The description of tensegrity principles as applied to the human spine was proposed by D.L. Robbie, MD. In his 1977 paper, Robbie explained how the principles described by Fuller apply to human physiology, arguing that the vertebrae of the spinal column, in concert with flexible elements such as fascia, ligaments, and tendons, act as discontinuous tensional elements. In the proposed model, force, and the expression of power, alternate with compressive and flexible elements that work together to form the body’s continuous tensional system. Robbie’s theory is supported by analysis of the spinal vertebrae, which are not designed to support significant weight, but rather to function as attachment points so that the ligaments and tendons around the spine are able to lift each vertebra off the one below it.
Robbie Figure 1. This linear diagram illustrates how vertebral body one is suspended over the vertebral body two by the tensional properties of the connective tissue as opposed to the compressional properties of the vertebral bodies.
Robbie Figure 2. This is an actual drawing of L-1 and L-2, showing the relationship between the inferior articular process of L-1 and the superior articular process of L-2
Schematic Diagrams of an Intervertebral Joint between the First and Second Lumbar Vertebrae
As Robbie explains, these drawings illustrate the structure and support of the first and second lumbar vertebrae (Figs 1, 2). Note that the upper tip of the superior articular process of L-2 is situated higher than the lower tip of the inferior articular process of L-1 … The connective tissue forms a sling by which the inferior articular process of L-1 is suspended from the superior articular process of L-2. If we now expand our view to include both intervertebral joints between L-1 and L-2, we see that the weight of L-1 is being supported by L-2 by means of a tensional rather
than a compressional force.”
From D.L. Robbie, MD. [i]
[i] Robbie D.L. 1977 “Tensional forces in the human body,” Orthopedic review 6: 47.
Akin to the flexible support structures of dome tents and sailboat masts, the body does not rely on a single, dominant “post” (e.g., the spinal column) to lift and move against the forces of gravity. It functions as an integrated system, involving stretchy tendon and fascia “wires” being integrated with rigid structures -- principally the bones -- that act as “struts” (Diagrams 11-23). Together, these work cooperatively to lift, move, and bear weight. [i]
In regard to the human body, the following definition of a tensegrity structure is provided by James Oschman, PhD:
[Tensegrity in the human body is] characterized by a continuous tensional network (tendons) connected by a discontinuous set of compressive elements (struts). A tensegrity structure forms a stable yet dynamic system that interacts efficiently and resiliently with forces acting upon it. [ii]