Try this: You’re probably seated in a chair right now. Move just your foot up at the ankle towards your shin (ankle dorsiflexion). You could probably manage to move it a few inches. Now extend your leg straight out in front of you and again try to move your foot towards your shin at the ankle joint. Not quite as far, right? Now keep your leg extended out in front of you, but bend forward and try to move your foot towards your shin. Even harder. One last time, bend forward at the waist with your leg straight out in front of you and bend your head down towards the ground before attempting to move your foot towards your shin. If you’re like most people, you would hardly be able to move your foot at all, and you would feel tightness running up the back of your leg and into your hips. This is a simple demonstration of the continuity back-line fascia chain, which runs from the bottom of your foot, to the back of your leg, up your back itself and even onto the skull towards the occipital muscles of the eyes.
What is fascia?
The word fascia (pronounced like “fah-shah”) comes from the Latin word for “band”, because fascial tissue resembles a band or sheath of connective tissue - mostly collagen - beneath the skin that “attaches, stabilizes, encloses, and separates muscles and other internal organs.” Fascial tissue extends through the entire body as a continuous, three-dimensional support matrix. You can conceptualize it by thinking about a peeled orange. Beneath the skin of the orange, the juicy flesh is compartmentalized by thin, fibrous layers that separate the fruit into wedges. Those layers that support and separate the juice and seeds of the fruit into pods are like the fasciae of the human body, which provide structure and shape to all our muscles and organs.
If the orange didn’t have “fasciae” it would be more like a water balloon filled with juice than a fruit that you could take a slice of into your hand.
The components of human fascia are interconnected throughout the body, making up a “three-dimensional architecture that is a multilayer system of interconnected sheets.” This continuity explains why, as in the demonstration above, tilting your head forward can affect the movement of your foot at the other end of your body. An important implication of this is a domino effect of injuries - in our bodies, nothing happens in isolation - an injury or limitation in range of motion in one part of your body will necessarily affect everything else up and down the chain of fascia.
The fascia is classified into three categories:
1. Superficial Fascia
2. Deep Fascia
3. Muscle-Related Layers (Epimysium, Perimysium, and Endomysium)
The superficial fascia is found directly underneath the skin and is made of a web of collagen and some fibers of elastin. It is found under every part of the skin except for the soles of the feet, palms of the hand, and in the face. Deep fascia is a membrane that extends through the whole body and envelopes all our nerves, blood vessels, organs, and glands. Epimysium is the fascia that encloses individual muscles, this type of fascia can be thought of as a thick Saran-wrap around every muscle.
Function of fascia:
Fascia helps muscles to transmit force through the elongation and contraction of itself. It can act like an elastic spring, absorbing, storing, and releasing kinetic energy. Particularly the Achilles Tendon in our ankle acts in this way – have you ever described someone as having a lot of “spring in their step”? The ubiquity of that expression proves again that common wisdom is often ahead of science. Our language often uses metaphors to communicate that are surprisingly accurate. You may also find it interesting to know that Leonardo DaVinci accurately drew fascia in his anatomy drawings a few hundred years before fascia was described in detail by medical science. 
(Selection of one of DaVinci’s many anatomical drawings)
Another good example of a function of fascia comes from down-under: kangaroos use connective tissue - fascia - as a spring to propel themselves through the air and move around. Each time the animal lands, the band of fascia is compressed, and then when their muscles initiate the next hop, the band is released, making the work of the muscles easier. Have you ever experienced “runner’s stitch” - a painful feeling on the side of the abdomen after running around and breathing heavily. It is thought that this phenomenon is caused by a distension of the liver and/or kidney organ fascial capsules.
Pain & Fascia:
Fascia is also thought to play a role in pain. Pain that seems to be associated with muscle - like muscle soreness after the gym - may actually be caused at least in part by fascia. Increased fascial stiffness may lead to, or contribute to myofascial pain. Many common conditions like “runner’s knee”, “tennis/golfer elbow”, “frozen shoulder” and fasciitis (e.g. of the plantar area of the foot) are also associated with a stiffening of fascial tissue. Unspecific back pain is also thought to be affected by fascial structures, as many areas of fascia on the back are rich in pain receptors. Stiffening of the fascia can lead to cracks, muscle hernias, and mechanical irritations can result in malfunctions and painful contractures. Painful muscle contractures and spasms are mostly associated with an increased in fascial tissue in that area – though it’s not known if this represents fascial tissue getting stuck around the area of the spasm as a fascial adhesion or an actual new growth of tissue.
It is known that stiffening and thickening fascia can lead to pain and malfunction, so it is essential to keep your fascia supple so they can glide smoothly over your muscle. You can work to this end through the application of heat and cold (e.g. in the shower or with a hot item placed on your back) as well as regular exercise that will keep the fascia moving. Another common way that fascia can be beneficially manipulated is through manual therapy. Manual therapies include various forms of massage and essentially any use of the hands (or a tool/machine) in order to apply pressure to different areas of fascia and muscle in the body. Such massage can not only be deeply relaxing, but astoundingly beneficial. Manual therapy can also prove to be a practical demonstration of the interconnectedness of fascia in the body. A fascinating case study makes this point clear: A patient with muscular dystonia of the eyes (benign essential blepharospasm – basically a spasm of muscles controlling the eyes) was examined by a manual therapist, who found that he could trigger spasms of the patients eye through postural changes, a deep touch to the lateral chest, and most fascinating, touching the posterior calf muscle. That’s right, the muscles controlling the eye were directly affected by touching the calf muscle on the other end of the body. The patients symptoms were improved with less intense and less frequent spasms after 10 sessions of manual therapy. Massage has also been shown to improve balance in people with chronic fatigue. Mechanical loading of tissue through massage and other methods can help to reorient the nervous system to better activate muscles and ensure that fascia can slide smoothly on top.
To summarize, fascia is a supportive, spring-like wrap that surrounds your muscles and organs. It contains blood vessels and sensory receptors. Healthier fascia may be one of the secrets leading to greater physical strength, explosiveness, agility, balance and flexibility. You should care about your fascia because if it gets injured it will lead to compensatory patterns over time that affect every other part of your body, preventing you from feeling as light and agile on your feet as nature meant you to be. You can take care of your fascia through massage, self-myofascial release (e.g. foam rolling) application of heat and cold, and regular activity. These activities help teach your nervous system to relax tension in the fascia, preventing stiffening that leads to dysfunction. I will leave you with one final exercise to demonstrate the power of fascial manipulation. Stand up, and try to touch your toes. Remember how it feels and how far you could go. Now take your shoes off, and find a tennis ball or something similar. Place the ball under the arch of your foot and place some weight on top of it, massaging the whole arch by rolling the ball back and forth. Do the same with your other foot. Now try to touch your toes again. You should find it easier this time. By manipulating the fascia on a small part of the body, we affected the tightness of the entire leg. Imagine the power of manipulating large portions of fascia, like on the back.
 Marieb, Elaine Nicpon; Hoehn, Katja (2007). Human anatomy & physiology. Pearson Education. p. 133. ISBN 978-0-321-37294-9.
 Schleip R, Jager H, Klingler W. What is ‘fascia’? A review of different nomenclatures. J Bodyw Mov Ther. 2012;16:496–502.
 Findley, T., Chaudhry, H., Stecco, A., & Roman, M. (2012). Fascia research – A narrative review. Journal of Bodywork and Movement Therapies, 16(1), 67–75. doi:10.1016/j.jbmt.2011.09.004
 Picture courtesy of UK’s Royal Collection: https://www.royalcollection.org.uk/sites/default/files/file-downloads/9781909686834_High%20Res..pdf
 Findley, TW 2007 Structural integration (Rolfing) for blepharospasm: effects of whole body myofascial treatment on a focal dystonia. Poster Presented at First International Fascia Research Congress, Boston, MA