Does fascia matter? The simple and definitive answer to the question is both yes and no.
Fascia is a topic that has been at the forefront of discussion recently within the fitness industry. Part 1 of this article focuses on the importance of fascia and how its specific properties are vital for the successful operation of the body. Part 2 looks at why fascia is not so important when it comes to designing and implementing exercise and training programs.
Why Fascia Matters
Fascia matters because it envelops our structure and influences the tension and integrity of the entire body.
Fascia has previously been thought of as a passive structure. Now, the evidence of mechanoreceptors, smooth muscle-like cells (myofibroblasts), and an increased understanding of the properties of collagenous tissue have started to change our understanding of fascia; it is now understood to be a more active structure that can exert a biomechanical force on the body. An appreciation and awareness of the properties of fascia means we can increase our understanding of the operation of the body as a whole.
Fascia Connects the Body
The power of the fascial web may lie in the fact it wraps around the body connecting it from top to bottom. This means it is ideally placed to transmit tension around the entire structure.
This is can be both a good and bad thing because as it can help to dissipate tension forces from one area it can also transfer them to another. Tension also helps to transmit information around the body as the mechanoreceptors respond to the stretch and strain that the fascial web is under. The strategies the body can apply to achieve movement in a sub-optimal environment, however, can be as destructive as they are helpful.
Thomas Myers, a leading pioneer in fascial research, sees fascia as a “a global way of looking at musculoskeletal patterns that leads to new educational and treatment strategies.” Beyond this, it also “leads to a directly applicable understanding of how painful problems in one area of the body can be linked to a totally silent area at some remove from the problem” (Myers, 2001).
This is a powerful message to understand. One area of the body may affect another. Localized stiffening of the system or excessive motion could affect the ability of an area to go through a range of motion or equally may create instability in the system. This could affect a removed segment that now has to create excessive motion or lock down movement. This will create associated tissue stress, as the tissues will have an altered length tension balance and cannot operate effectively.
One question that we might ask here: Should this knowledge lead us away from a symptomatic approach to injury that may prove ineffective in a significant number of cases?
Plastic Vs. Elasticity and Stiffness
Why does fascia having an active force on the body matter and how does it do this? The answer could lie in its stiffness. Stiffness is a property exhibited by a structure. It can be defined as an elastic material’s ability to resist deformation; it is how little it stretches when under load. The inverse of stiffness is compliance; this means that a substance will stretch when under load in a classically elastic manner. The level of stiffness means a structure can take much more stress prior to deformation in the elastic zone before it plastically deforms or breaks. Fascia is a collagenous substance, and collagen displays a high level of stiffness. Collagen is also subject to creep and will deform plastically under low load levels. This means it will remain in its new shape and not return to its previous state or length as an elastic structure would. This would have implications for long-term low loading situations, such as static postures. Under higher mechanical load, however, it will have an elastic response or, more specifically, a stiff response. As Siff states, “The biomechanical performance of collagenous tissue depends largely on their loading rate” (Siff, 2003).
As we can see in Image 1, the stiffness is highlighted in the linear elastic range. This will increase with strain until the elastic limit is reached.
The low range of plastic deformation is highlighted in Image 2. This is described as creep.
This visoelastic (both plastic and elastic) view of fascia has many implications for the body. Fascia contains some viscous liquid that creates friction and deformation that swallows or dissipates energy.
Purely elastic material returns much more of the energy put in and will follow Hooke’s law that elongation is directly proportional to applied force. The energy lost during elongation of a more viscous material is known as the hysteresis. Hysteresis is caused by heat and internal friction and will mean the energy required to return to the structure’s original length will be dissipated during deformation. The elastic property of stiffness under higher loads means that less deformation occurs and more energy is returned.
Fascia cannot fully return to its original length after exerting its stiff properties on the system, as it will lose energy through its viscous properties being visoelastic and therefore have some plastic deformation. Instead, the muscles have to perform this function for it. Essentially, the muscle forces will help reset the fascia’s plastic element while the fascia could be said to control muscular elasticity through its stiff properties.
The body’s tendenous structure can be seen as an extension of the fascial system. The visceoelasticity of collagenous tissue will vary, however, since there are at least ten distinct types of collagen in the body with different tensile properties (von der Mark, 1981). Schleip states that “tendons may be regarded anatomically as local thickenings of fascial sheets” ( Schleip, 2005). The Achilles tendon returns up to 93% of the stress energy applied to it and only loses 7% to viscous friction (Ker, 1999).
So why is this important? Motion requires energy, so the more the body moves, the more work the muscles have to perform and therefore the more energy is used. Large muscular motions that would be allowed by a more simple elastically compliant system would be very energy consumptive. This means that it is more thermodynamically efficient, or, more simply put, energy-saving to have a stiffer system. The stiffness of the system also allows for faster movement. Moving bones via soft compliant tendons would make us very slow (McMahon, 1990). Both Zorn and Schleip relate this evolutionary change to the fact being slow would make us easy prey to catch: “Our biological make-up has been shaped through a Darwinian process of selective survival, including countless fight and ﬂight reactions. Life-threatening situations often involve rapid and strenuous activities…It would make biological sense that animals equipped with an additional mechanism to muscular coordination for a temporary increase in tissue stiffness would have a distinct advantage” (Schleip, 2005).
But if the presence of myofibroblasts (MFB) means that fascia could be contractile in a smooth muscle-like manner (Schliep, 2005), how would it do this? For a start, the usual neural synapses does not innervate fascia. Instead, mechanical tension and chemical elements cause MFB activity.
As we have seen in muscles, contractions can happen in different ways: mainly eccentrically, isometrically and concentrically. To be stiff it would make sense that it lengthens, but not a lot. This would mean it was similar to an eccentric contraction, responding to mechanical tension in the system. A concentric contraction would require a more energy-consumptive demand on the system, and an isometric contraction would mean no change in the shape of the fascia, which would reduce adaptability in the system and make it essentially non-reactive. This would also have implications for blood flow in the system. A similar mechanism to the muscle spindle that increases tone or shortens the fibers has not been documented in fascia. The spindles contain both sensory and motor components that are innervated by the central nervous system (CNS). In this way they can provide an active shortening of the tissue. Yahia has hypothesized that there could be the “possibility that muscle fibres capable of contracting spontaneously could be present in lumbodorsal fascia ligaments” (Yahia, 1993). Chemically induced contractile and relaxation responses have been document in vitro in rat lumbodorsal fascia (Schleip, 2006) and pathological fascial contractures have been cited as adding weight to the fact that fascia is contractile (Schleip, 2005).
More investigation, however, is needed to understand if fascia does actually contract in vivo, what the implications are for tissue length, the mechanisms behind fascial contraction and whether this is neural, mechanical or chemical in nature.
The stiffness of fascia also has implications for proprioception. The fascial web acts as a giant GPS system for tension and movement. The large amount of Golgi mechanoreceptors present in the fascia will respond to the strong stretches that would occur in a stiff system. They also live in the joint capsules, apernurosis and ligaments and as Golgi tendon organs (GTO’s) at the musculotendinous junction. Only 10% live within the tendon itself. The Ruffini endings and Pacinian corpuscles also populate the fascia in abundance (Yahia, 1992). They have differing roles, the Ruffini endings having a lower mechanical threshold and therefore respond to slower movements , while the Pacinian an corpuscles are much more sensitive to high velocity motion. The presence of these receptors shows the high sensitivity of fascia to movement. The Pacinian an corpuscles may also have some implication on the autonomic functions, heart rate, respiration and blood pressure (Coote & Pérez-Gonzáles, 1970) rather than just on the tension of the system through the change in tonus of motor units associated with tissue. The sheer volume of mechanoreceptors in the fascial sheet gives it enormous feedback to the CNS.
The proprioceptive role of the fascial web means it can update the CNS on mechanical tension to operate the muscular motor units at the right time, rate and force level. As a result, fascia is vital to the correct operation of the system. The CNS does not work in muscles, as they are never activated as a whole or individually, but in an overall number of motor units. Depending on the ability of the system, millions of motor units can be regulated at one time (Basmajin, 1985).
Fascia brings us back to the body as a whole unit rather than the collection of individual parts we have become in the laboratory or clinical settings. It now comes down to us as practitioners to provide the right stimulation to allow the success of all parts of the body to interact and produce free-flowing and highly adaptable movement. We can reduce input into the system by isolating the myofascial structures from each other and by creating localized and isolated individual muscle or fascial related movements. This will create unnatural tension and inhibits the system’s ability to dissipate force and act as a unit. This is not an approach that leads to functional success. In this author’s opinion, this can only be done through functionally authentic input to the system in terms of movement, environment and intensity for systemic processing and successful output.
One area of interest is the ability of emotional stress to create a stiffening of the fascial system. The biochemical activation of MFB or the fascia as a whole due to illness or work related stress could inhibit movement of the body through increased stiffness and lead to lower back and joint pains as well as other movement dysfunctions. The discovery of Integrins—mechanoreceptors that communicate tension from the exterior fiber matrix to the interior of the cell itself—could mean that physical tension may affect the body on a cellular level. This creates a situation where emotion can affect tension and motion, and tension and motion affect emotion. Going one step further, could tension affect the body on a hormonal level, also influencing stress and mood?
This now creates the link between the mind, body and spirit for a truly holistic view of the operation of the body and its relation to its functions.
Another area for discussion is the role of the fascia in the stiffening of the system after fatiguing exercise, both immediately post-exercise and after longer periods of rest. Does or can the system reduce movement because of the increased energy consumption on an already fatigued system? Or because of the thermodynamic demand that larger range or more elastic motion incurs? These processes are intrinsically linked so it could also be a combination of both. The stiffening of the system could have an impact in this situation as a protective mechanism and energy saving device.
In Part 1, we have looked at the properties of fascia and its importance to the functional operation of the body as a unit. In Part 2, we will discuss why looking at the isolated properties of fascia when training the body is not the optimal or sensible approach.
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