Tensegrity & Regional Interdependence
Traditional anatomical education focuses on the structural and mechanical understanding of individualized human structures, such as muscles, ligaments, nerves, and organs. While anatomy textbooks list that we have roughly six-hundred muscles, it is more accurate to say that we have one muscle and six-hundred pockets of fascial webbing. Fascia is a densely woven system in the body, resembling a spider’s web, that covers every muscle, bone, nerve, and organ. It should be noted that these fascial coverings are not separate entities. They are part of one continuous structure that wraps us from head to toe without interruption. In this way, you can see that each part of the body is connected to every other part by the fascia, like a gigantic spider’s web. However, this limited description of fascia only encapsulates its function from a morphological tissue and structure perspective. In 2007 at the International Fascia Research Congress, Robert Schleip and Thomas Findley proposed a much more nuanced definition of fascia stated as, “ Fascia is the soft tissue component of the connective tissue system that permeates the human body, forming a whole-body continuous three-dimensional matrix of structural support. It interpenetrates and surrounds all organs, muscles, bones, and nerve fibers, creating a unique environment for body system functioning. The scope of this definition and interest in fascia extends to all fibrous connective tissues including aponeurosis, ligaments, tendons, retinaculum, joint capsules, organ and vessel tunes, and so forth”.
Tensegrity and Tissue Properties
As a human being, you are a massive network length-tension relationship. Whatever muscles may be doing individually, they also operate across integrated body-wide continuities within their fascial webbing, which forms a connective tissue fabric that warps to the shape of the body. Thus, all tissues are interconnected and all force transmission or strain will be ‘felt’ by all tissues to some extent. In this way, our bodies act like tensegrity structures where the name is a portmanteau of the words ‘tension’ and ‘integrity.’ By definition, tensegrity is the characteristic property of a stable three-dimensional structure consisting of members under tension that are contiguous and members under compression that are not. In art and architecture, the principle of tensegrity is demonstrated in structures such as that seen in the figure below.
Buildings do not act like tensegrity structures. For example, if a tree comes crashing down on one side of the house it will damage the roof and the structural components under that spot may collapse, but the rest of the building will remain in perfect condition as if nothing happened. The building collapsed where force was directly applied and where the strain was most significant. This is intuitive and easy to understand. If you smash the downstairs window of a house with a baseball you wouldn’t expect the upstairs toilet to shatter. However, that is not the case with a tensegrity structure, like the human body. A tensegrity structure breaks at its weakest point regardless of where a force is applied. Therefore, as humans and tensegrity structures a stressor applied to our foot or shoulder may manifest as pain in the lower back or vice versa. The human pelvis, which consists of three bones fused together, is a great example of the principle of tensegrity. Without muscles, ligaments, and fascia the pelvis would float somewhere around our midsection. Luckily, this isn’t the case. The pelvis is like a house of cards, and what keeps a house of cards from collapsing to one side or another is an equal amount of tension imparted in each direction. On the front of the pelvis we have the hip flexors and on the back we have hamstrings. If the hamstrings lack tension the pelvis will tilt forward and give the hip flexors leverage. Additionally, if one or both sides of the pelvis carry too much tension then an individual will be more prone to injury, which will manifest where the tensegrity structure is weakest.
If you want a practical demonstration of how our bodies act like tensegrity structures you can attempt a forward fold, marking how far down you were able to touch. Then spend forty five seconds to a minute rolling a lacrosse ball under your bare feet before retesting your forward fold. There is a high probability that your ability to reach further increases. The reason for this is that the sole of the foot and hamstring are connected via the superficial back fascial line and as a result the rolling of the foot provided neurological stimulation that caused a decrease in tension both in the foot as well as through other areas in the superficial back line such as the hamstring. This is a case where a local intervention has a regional effect on tension, which is only possible because the relative tension in any given area of the body is influenced by the tension in other interconnected regions.
If we choose to use this model as our way to view the structure and adaptation of bio-organisms, then we can start to consider how stress being applied to the human body can lead to targeted and specific adaptations depending on what type of stress is applied and where it is applied. Different forms of mechanical stress are classified in a multitude of ways including torsion, tension, shear, ease, compression, stretch, bending and friction. Each of these different mechanical stresses lead to a different form of mechanotransduction, which is the process through which cells sense and respond to mechanical stimuli by converting them into biochemical signals, which elicit specific cellular responses. This process of turning mechanical stressors into chemical activity is capable of changing gene expression and our inflammatory response. For example, if you perform a set of moderate load bicep curls to failure you will stimulate the mechanoreceptors in your bicep, which will lead to a cascade of biochemical responses that will help shape the way you adapt to that mechanical stimulus.
Fascia and Fascial Lines
Regardless of what muscles do individually, they also affect tissues throughout the entire body through fascial based interconnections. These interconnections are called facial lines and are seen by tracing the body’s connective tissue structures during dissection. Fascial lines help create stability, movement, elasticity, compensatory postures. While all tissues in the body are linked to the fascial network, the fascial lines can be distinguished and viewed as distinct entities. The various fascial lines are as follows:
Superficial back line - the superficial back line connects the entire posterior side of the body running from underneath the feet to the top of the skull and it helps keep the body in an upright posture. Because of the structure and function of this fascial line it’s not uncommon that athletes lacking intrinsic foot strength and flexibility present with lower back pain. When viewed through a traditional lens this type of back pain’s origin is often mysterious as it cannot be attributed to a standard local tissue related diagnosis, however when looking through the lens of the fascial theory alternative explanations can be gleaned.
Superficial front line- the superficial front line connects the entire anterior side of the body running from the top of the feet to the sides of the skull. This fascial line is in juxtaposition with the superficial back line when the body is upright and the hips are extended, though it should be noted that this line helps to create flexion.
The lateral line - the lateral line begins on both sides of the body on the center of the foot and frames the body by extending along the outside of the leg and thigh, passing over the torso in a zigzag pattern and attaching near the ears. The function of the lateral line is to stabilize the torso relative to the legs, to help with coordinating full body movements, and to control forces transmitted from the superficial front and back lines.
The spiral line - the spiral line creates a loop around the body in two circles, running opposite one another right and left. Starting at the skull, these lines cross the upper back and run under the arms until they go around the chest crossing each other at the naval and then running to the sides of the hips and forming an ‘X’ before trailing down the outside of the thighs, running under the feet, and finally running back up the thighs and converging at the spinal erectors. The spiral line stabilizes the body in all planes of motion and is especially useful for regulating the position of the knee during the gait cycle by connecting the foot and pelvis. Because of the position of the spiral line individuals with excessive hip flexor tone or strength, compared to pec tone or strength, often present with lower back pain.
The arm lines - the arm lines are the most complex of those previously mentioned since they run through the shoulder joint in four different planes and along the arm on multiple sides including two deep lines on the front and back of the arms respectively. With the structure and function of these lines in mind, we can consider how this influences exercise selection. For example, if we want to train our biceps through all of the functional ranges of the muscle we cannot only rely on standard single plane pronated and neutral grip curl variations. We may also want to incorporate other functions of the bicep into our training repertoire including bracing the arm in a locked out position, creating shoulder flexion, and working rotationally along the plane that the muscle fibers are laid out.
The functional lines - the functional lines cross both the front and back side of the body, creating a large ‘X’ on both sides. Additionally, a third function line runs from the shoulder to the inside of the knee on the same side. The functional lines are not very active during static standing posters, do aid in stabilizing the body and generating power in movements where we push off the ground to create force from the opposite side of the body. For example, winding up to throw a punch by pushing off the ground and rotating the hips.
The deep line - the deep lines forms a three-dimensional shape rather than a line, taking up more space than any other fascial line and running through the legs, around and the torso, through the chest cavity, and around the neck. The deep line contains many stabilizing muscle fibers and can be contraindicated in many injuries if dysfunction is present.
By working in sync with one another the different facial lines aid in the generation of balanced, fluid, and integrated movement. This runs counter to the traditional view of muscle function where muscles work only at their point of origin and either contract or resist. When we consider fascia’s ability to transmit force the picture becomes much more nuanced. In the past, fascia has been viewed as a passive structure that gives the muscle extra support and serves as a second skin barrier. However, it actually serves an integral role in the human body. Contrary to popular belief, fascia is not a passive tissue and it has the ability to contract and has its own sensory network. On a pound by pound basis, fascial can have upwards of eight times the tensile strength of muscle tissue. It is my speculation that the contractile abilities of fascia are responsible for many of the superhuman feats of strength seen by acrobats, climbers, gymnastics, and elite weightlifters who can squat upwards of four times their bodyweight.
Pound for pound gymnasts and acrobats are some of the strongest athletes and if you gave them a barbell it is likely they would outperform many high level strength athletes. Yet, gymnasts and acrobats rarely train with weights. I believe much of that strength comes from the fascial system, which is developed as a result of their training with complex and full body integrated movements under loading. These movements which often involve twisting, contorting, and rotating under load are the perfect stimulus for creating adaptations in the fascia and exercising it’s contractile abilities. However, most people simply cannot perform these movements let alone do so under load due to the fact that their fascia is bound up as a result of repetitive training in a single plane of motion, and repetitive postures. In order to depict the negative effects these inputs have on fascia I like to use the following tee-shirt analogy. If you pull up on the right corner of your tee-shirt the whole shirt will move along with it, not just that corner. Then when you let go of that corner the shirt will snap back to its original spot and there will be no wrinkles in it. But, if you pull on that corner and hold it there for hours, or days, when you release it, it will not snap back and there will be wrinkles. This is akin to what happens to our fascia when we perform repetitive training in a single plane for years on end. A good example of this is shoulder or pec minor pain that comes from repeated bench press training. Through a traditional lens one might say that an athlete can just do some external rotation work or rear delt work to offset the bench pressing or balance out the motions, but in practice this seldom works. Comparably, an athlete will always be able to overload the pecs more than their antagonists and, as a result, viewing the body through this narrow structural balance perspective is not the answer. It’s not uncommon for athletes to also try to take the approach of doing horizontal rowing to offset horizontal pressing, but this is equally misguided as the pecs and lats both function as internal rotators of the humerus which further compounds the issue. It is only through the lens of holism that we can begin to move in the right direction by viewing the body as a single integrated unit. This means addressing restrictions in the fascia, breaking the pattern of repetitive motion, and training with complex movement patterns that integrate the body as a single unit, as well as incorporating principles of functional bodybuilding into training.
Functional bodybuilding is a term that has quickly gained exposure in the fitness market, and there are as many conceptions and variations of it,. For lack of a better term, I am going to refer to the concepts discussed in this section as functional bodybuilding based training concepts, but they shouldn't be confused with other modes of training under the same guise. These training concepts are loosely based on the concept of fascial lines along with knowledge of muscle origins and insertions, as well as the structure and function of different muscle groups. I have personally used them with many clients, and there appears to be good empirical evidence supporting their use.
Generally, when people think of functional bodybuilding they envision exercises which are perceived to have carry over to everyday life and are performed in lower rep ranges than you would traditionally see in bodybuilding training. When I refer to functional bodybuilding this is not what I have in mind. Instead, I think of incorporating the structure and function of a muscle into the movement pattern as well as designing body part splits based on the fascial lines. For example, traditional body part splits often combine back and biceps training, or chest and triceps training. This seems intuitive on a surface level but when taking a ' functional bodybuilding ' view one might pair back and tricep training due to the fact that they have similar insertion points near the armpit and share anatomical function in certain ranges of motion. An example of the latter being a compound tricep pushdown. Another application of this idea is incorporating the structure and anatomical function of a muscle into exercise selection as would be the case when we pair exercises that bias the short head of a muscle with a resistance profile that loads the muscle in a shortened position, for example.
Regional Interdependence
Earlier in this article I stated that many musculoskeletal issues, like back pain, are often non-attributable to standard tissue related diagnosis and as a consequence of that we need to focus on the interrelationships between muscles and their functions to understand those types of issues. This is directly related to the concept of regional interdependence, which asserts that seemingly unrelated musculoskeletal impairments in remote anatomical or body regions may be associated with or can contribute to one another. Additionally, contemporary research on regional interdependence has shown that varying body systems can also be affected by one another. What this means is that the body needs to be observed in its entirety if we are to truly understand it. This runs in opposition to the traditional medical model where each component is assessed in isolation. Vladimir Janda, the late 1960’s Physical Therapist, was ahead of his time in understanding this concept when he stated, “The motor system functions as an entity. It is a principally wrong approach to try to understand impairments of different parts of the motor system separately without understanding the function of the motor system as a whole”. When we embrace this concept wholeheartedly, we can begin to see human movement from a holistic standpoint.
One way to view regional interdependence is through the interrelationship between mobile and stable segments of the body. If any joint that has it's primary movement in one plane of motion is considered a stable joint, and consider those that don't have just one primary range of motion a mobile joint, you can observe that the human body works in a pattern of alternating stable segments connected by mobile segments. For example, if we work from the ground up we can observe the following pattern of alternating mobile and stable joint segments:
Feet - Stable
Ankles - Mobile
Knees - Stable
Hips - Mobile
Lumbar Spine - Stable
Thoracic Spine - Mobile
Cervical Spine - Stable
Lumbar Spine - Stable
Thoracic Spine - Mobile
Scapulas - Stable
Glenohumeral Joints - Mobile
Elbows - Stable
Writs - Mobile
By looking through the lens of regional interdependence and alternating mobility and stability you can see how dysfunction in this pattern will occur through predictable patterns of compensation. For example, Crossfit athletes often present with low back pain, shortened hip flexors, and a lack of thoracic spine mobility. This lack of mobility and range of motion in the hips and thoracic spine, which should be mobile segments, causes a compensation pattern. As a result, the lumbar spine, which should be a stable segment, sacrifices that stability in order to obtain more range of motion. As a result, they often end up with low back pain that is non-attributable to the standard tissue based diagnosis and in turn it often goes solved. This same concept can be applied to other areas of the body as well. For example, one might lose thoracic mobility and get neck and shoulder pain as a result of that or one may lose wrist mobility and get elbow pain as a consequence. Thus, examination of joints that are both proximal and distal to joints that are afflicted with pain is a crucial concept of regional interdependence.
Thus far I have discussed the concept of regional interdependence as it relates to pain and rehabilitation. Specifically, how a lack of mobility or stability in a joint can impact the function, and cause pain, in the joints proximal or distal to it. However, this concept also has implications to, and applications for, sports performance. Whereas the mobility of a joint can impact those surrounding it, the strength and endurance of the musculature surrounding a joint can impact the function of muscles upstream from it. In 2018 Dr. Maximilian Sanno and his colleagues at the German Sport University of Cologne conducted a study titled, Positive Work Contribution Shifts from Distal to Proximal Joints During a Prolonged Run. The investigators found that as extended duration runs, at a slightly slower pace than 10,000m race efforts, are performed, runners progressively do less and less work with their ankles and progressively do more work with their knees and hips. What this shows is that as distal joints and muscles fatigue more proximal ones compensate to take the brunt of loading, raising the question of whether or not the runners could improve their performance simply by strengthening their ankles and improving fatigue resistance in the surrounding muscle groups. According to the investigators in this study, that does in fact appear to be the case. As a result, I would make the argument that athletes involved in work capacity sports that require high levels of strength and endurance train the fatigue resistance of muscles that are both proximal and distal to the primary muscles used in their sport. For a Crossfit athlete this can mean strengthening the feet, ankles, elbows, and wrists, all of which are often overlooked in training programs. Another application of this concept is what I refer to as landmark movement routines which can be performed as stand alone training sessions or tacked onto the back of a stimulative training session. Landmark movement routines consist of foot, ankle, diaphragm, thoracic spine, neck, and shoulder training. Addressing these common problem areas will often remediate upstream and downstream issues as well, making landmark movement routines a low investment insurance policy for athletes in a variety of sports. That said, if someone prevents with a specific pathology or movement dysfunction then that should be addressed with a targeted intervention. However, for those who move well and aren’t currently experiencing any pain or dysfunction you'll find a landmark movement routines are often enough to stave off injuries and improve resilience. Below you’ll find a sample routine for an intermediate to advanced Crossfit athlete.
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The fascias description is class, thank you Evan.