The fascia, this inner matrix that shapes our health
Long ignored, this tissue that holds our muscles and organs in place is beginning to receive special attention. A growing body of studies suggests that it has a role to play in the treatment of various pathologies such as chronic pain or immune system dysfunction.
Scientific revolutions can arise from the most improbable things. For example of a rat, in a laboratory, which stretches in the posture of the “upside down dog”.
According to some scientists, who have found a way to make rats do yoga, these little creatures benefit from a good stretching session just as much as we do. Moreover, their study reveals the true importance of a fabric ignored for centuries by science.
In the XNUMXth century, in England, the anatomist Erasmus Wilson said of this tissue – today called “fascia” – that it is a natural bandage. In dissection, this is exactly what it looks like: bands of fibrous, white connective tissue, gooey, sturdy but flexible, perfectly suited to hold muscles and organs in place. In addition, it prevents you from seeing the muscles, bones and organs it covers, which explains why, for years, anatomists cut it, removed it, threw it away, and soon forgot about it.
More recently, however, researchers have begun to take a fresh look at fascia and realize that it is anything but an inert envelope. In reality, it is the seat of a biological activity which sheds light on certain links between lifestyle and health. The fascia might even be a sensory organ of a new kind. "There's a lot more going on in the fascia than is generally believed," says Karl Lewis of Cornell University in Ithaca, New York.
An ubiquitous tissue in the body
We are becoming aware of the urgent need to study this ubiquitous tissue in our bodies more closely. With better knowledge, it might be possible to design new ways to tackle a host of common but hard-to-treat conditions, from immune system dysfunction to chronic pain.
One of the first difficulties facing the study of fascia is that there is no consensus on its definition. What is certain is that it is part of the group of connective tissues, which, according to their broadest definition, include not only tendons and ligaments, but also bones, skin and fat.
Most fascia researchers also agree that they are tissue membranes composed of strong collagen fibers and more stretchy elastin fibers. Often these fibrous membranes are separated by “areolar” or “loose” fascia, which contains fewer fibers, the spaces between them being filled with a slimy substance that allows neighboring layers to slide past each other. The main ingredients of this viscous soup are hyaluronic acid, which has a lubricating effect, and proteoglycans, molecules which act as shock absorbers. Fascia fibers and this soup are produced by specialized cells found in the fascia – the recently discovered fibroblasts and fasciacytes.
If you were to cut up a human body, you would easily discover two layers of this natural food film: the superficial fascia, which lies immediately under the skin, and the deep fascia, which wraps muscles and organs, and connects them to each other. . Some researchers extend the definition of fascia to include “visceral fascia” (which lines the belly cavity and divides it into compartments where different organs fit), as well as the thin layers of connective tissue that cover virtually every part of the body. According to this definition, the fascia forms a network that holds all the elements of our body together.
It is striking that, until the early 2000s, no one had studied this central tissue of the body in detail. Carla Stecco, orthopedic surgeon and anatomist at the University of Padua, Italy [author of the Functional Atlas of the Human Fascial System, published in 2020 by Tita Editions] is one of the pioneers. She focused on fascia twenty years ago, when her father, Luigi Stecco, a physiotherapist, developed a new physical therapy: “fascial manipulation”. According to him, this method would be able to cure everything, from headaches to muscle and joint pain. It is now part of the panoply of physical therapies based on the idea that massage can soften a fascia that has become too stiff.
In search of evidence
The problem is that at the time, there was no evidence to validate or invalidate the idea that massage could have a specific action on fascia and on pain. Since then, Carla Stecco and other researchers have shown that the fascia is rich in nerves, and that these transmit different information throughout the body. The nerves of the superficial fascia are specialized in the perception of pressure, temperature and movement. Those of the deep fascia are involved in proprioception (perception of the body's position in space) and nociception (perception of pain).
Scientists have conducted experiments in which healthy volunteers received painful injections into the skin, muscles and fascia. These experiments show that nerves in the skin and muscles cause localized pain, while the nerve network in the fascia produces radiating pain, the origin of which is more difficult to localize. This type of diffuse pain is characteristic of several chronic pain disorders, including fibromyalgia, which some studies associate with inflammation of the fascia. This diffuse character is also characteristic of post-exercise pain, which has long been attributed to muscle damage, but which researchers now attribute more to fascia injury or inflammation.
Bad news: when the inflammation lasts too long, the body changes the composition of the fascial nerves, which become more sensitive to pain. In rats, the proportion of nociceptive fibers – receptors that respond to painful stimuli – in fascia increases from 4 to 15% after chronic inflammation of deep fascia in the lower back.
This might explain why lower back pain is so difficult to treat. Although they are one of the most common causes of absence from work and restriction of mobility worldwide, in 85% of cases they are classified as “non-specific”, i.e. say that their exact cause could not be determined.
The thoracolumbar fascia is a diamond-shaped structure located in the lower back and made up of several layers, which connect to different groups of muscles in the trunk. Given our current knowledge, this thoracolumbar fascia seems to be the right place to look for the origin of our back pain. “The thoraco-lumbar fascia is like a large receptor capable of sensing the tensions coming from the upper limbs, the spine and the abdomen”, sums up Carla Stecco. And it could well be that the sensory neurons in the fascia interpret these tensions as pain.
The flexibility trail
Also, inflammation of the loose fascia could make things worse. Helene Langevin of the National Institutes of Health in Maryland used ultrasound imaging techniques to investigate the lower back. According to his results, people with chronic pain in this region have a thoracolumbar fascia that is 20% stiffer than people without pain. This stiffness appears to be because multiple layers of tissue are stuck together and prevent the loose fascia from slipping.
Studies she has conducted on pigs support this hypothesis: once the initial injury resolves, a lack of mobility in the lower back can maintain fascia stiffness and cause adhesions – areas where two layers are stuck together. to each other by new collagen fibers. These adhesions, as other studies suggest, restrict movement not only in the fascia that is in close proximity to the stiff zone, but also in nearby connected regions. In some extreme cases, the layers of fascia can adhere to each other to the point of forming an immobile block that goes from the superficial fascia to the deep fascia and the muscle.
Besides injury and inflammation, many factors can impair the flexibility of the fascia. According to research by Robert Schleip of the Technical University of Munich, activation of the sympathetic nervous system (involved in the fight-flight response) causes the fascia to contract by instructing the fibroblasts it contains to transform into myofibroblasts. These cells are part of the inflammatory response to injury, often involved in joint problems such as adhesive capsulitis (or frozen shoulder).
We are far from finished studying how the fight-flight response [implied by fear or stress, for example] causes stiffness. That said, Robert Schleip already thinks that adrenaline would increase the expression of an inflammatory substance, TGF-beta. This would then be stored in the loose fascia in anticipation of the next time the body is stressed. When this happens, the fibroblasts “absorb the TFG-beta and transform within hours into myofibroblasts,” he explains. He adds :They are then four times less flexible than before. They are contraction machines. This is how adrenaline can stiffen the fascia.
In fact, the list of factors that can alter fascia elasticity is growing as our research progresses. “Estrogen can create a more elastic fascia, assures Carla Stecco. Fascia is a very dynamic tissue capable of reacting to hormonal, chemical and mechanical factors. These factors, taken together, determine the elasticity of our fascia.”
Stretch for better health
On the bright side, because fascia is dynamic, there are strong reasons to believe that changing our lifestyle can fix some fascia-related issues. Especially when doing stretches. In rats, Helene Langevin observed that stretching leads to modifications of the fibroblasts which constitute the matrix of the loose fascia: they multiply, lengthen and flatten. “Stretching relaxes the tissues,” she insists.
Other studies she has done on pigs indicate that stretching the lower back twice a day for five minutes not only reduces the size of an inflamed area, but also appears to trigger a sequence of anti-inflammatory chemical events. inflammation originating from the fascia. This finding is promising because chronic inflammation is associated with nearly every modern disease, from heart disease and diabetes to cancer and depression.
A team from Harvard Medical School is conducting a trial with humans to determine if the same is true for us. In the pilot study she completed at the end of 2021, the group of healthy volunteers who stretched for an hour had altered levels of cytokines, molecules [involved in inflammation in particular] belonging to the immune system, for example compared to the group that had not stretched. These results suggest that stretching results in regulation of inflammation.
As for physical therapies that focus on the relaxation of fascia, such as massage, it is still unclear whether they have the same cellular and anti-inflammatory effects as stretching, or whether they only have a temporary action. on the fascia. It could be, for example, that as manual therapies warm the tissues, they make the fascia matrix less viscous and temporarily allow the different layers to glide better over each other. Prudent, Helene Langevin recalls that, as long as we do not know more about the mechanisms of these therapies, we cannot know their effects on the fascia – if indeed they have any.
Before this research translates into evidence-based treatments, fascia will need to restore its image among scientists. Its bad reputation dates back to the 1940s and 1950s, when classical medical research paid little attention to it and it became the central object of an alternative therapeutic method developed by the late [American] biochemist Ida Rolf . Called “structural integration”, but better known as “Rolfing”, this method is a mixture of physical therapy and assumptions about the alignment of the body's energy fields. Since then, "fascia" has been a buzzword in all kinds of alternative therapies.
Anyway, for Carla Stecco it is high time that conventional medicine took a little more interest in this tissue and recognized its importance in many areas. We should finally understand that it opens a window on human health. This would be, according to her, “the real fascia revolution”.
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