Yin tissues are the tissues of the body that are typically more dense, plastic (inflexible), hidden (located deeper in the physical body) and hold the cumulative patterns of our lifestyles. When we practice Yin Yoga we are targeting the joint sites (composed of bones, ligaments, tendons and synovial fluid) and fascia. Because the nature of these tissues is to bind and protect, they appear to be “stubborn” and require our dedication and patience to mobilize, repattern and strengthen. Whereas the yang tissue of muscle responds quickly to stretching and strengthening, the yin tissues require:
a) loading the joint or fascia for several minutes instead of several breaths
b) regular practice over time (months and years) to appreciate the full spectrum of benefits
Loading — applying any kind of force to a tissue or area of the body. Loading can be done through compression, stretching, tractioning and torquing or a combination.
Unloading — removing force from a tissue or area of the body; giving it “slack”.
The beauty of a “yin journey” is that each step reveals something valuable to us. Some of the benefits are noticeable the first time we take a class and many more become apparent as we mature with our practice.
Many people find Yin Yoga after they have already established a fitness routine or have tried other styles of Hatha Yoga. While there are many reasons someone may be intrigued by Yin Yoga, one common motivation is to “unstick” the most inflexible parts of the body. Tense shoulders or tight hips that haven’t “opened” from stretching will respond to a regular Yin practice. Working with yin tissues can significantly improve mobility but it is important to note that the shape of joint will not change if restriction is due to a bone-on-bone limitation. Paul Grilley offers anatomy courses that explore different types of restriction in the body and illuminates why it may be impossible for one human to look the same as another human in a yoga pose. While it takes some dedication, the results of a regular yin practice will be more enduring than a physical stretching regime. Relatively speaking, your muscle memory is short-term and your connective tissue memory is long-term.
We can all benefit from Yin Yoga at most stages of our lives because we all fall into movement habits and neglect certain ranges of motion. All of us experience stress, injuries and lifestyle limitations that form patterns of tightening and protecting. Even those of us that make a conscious effort to live healthy lifestyles will fall into routines that limit our mobility as the body seeks efficiency at the expense of diversity.
Yin techniques can slowly unwind long-held patterns that have accumulated and maintain existing ranges of motion and strength. To understand how to maintain and reclaim the health and mobility of yin tissues we will look at the composition and function of each anatomical component.
JOINTS
A joint is defined by the joining of two or more bones. The main structures of a joint are ligaments, tendons and bones. There are other connective tissues and lubricants in joints that are also essential to joint health.
Ligaments — connect bone to bone. Ligaments come in a variety of shapes like cords, sheets and bands. Most ligaments are predominantly composed of collagen (which makes them strong and durable) and there is some elastin allowing for flexibility.
Tendons — connect muscle to bone. Tendons are thick and do not stretch. Tendons connect to our myofascia which is stretchier than a tendon. If we apply traction to a tendon the more elastic myofascia will take all of the force and stretches while the tendon remains immobile. Too much of a stretch on this chain will cause a rupture at the junction where the myofascia and tendon meet, this is called the MT junction. According to Bernie Clarke, we cannot actually stretch a tendon, but we can stretch and strengthen the myofascia-tendon complex.
To work with these connective tissues we have to relax the muscles — once the muscles are relaxed the joint can be tractioned (the bones pulled apart) or “loaded” to stress the ligaments and myofascia-tendon complex. Appropriate levels of stress improve the health of connective tissue.
Ligaments and tendons are described as “plastic” rather than “elastic” because they can be damaged by sudden or extreme stress. This is why it is so important to move slowly, find healthy edges, hold the appropriate amount of time and listen to cues of the body.
Just like the other tissues in our body, the ligaments and tendons need blood flow to stay healthy. Better circulation in the connective tissue can be achieved through various yin techniques like:
Tractioning — achieved by organizing the body into poses, sometimes with props, and letting gravity “do the work” of gently pulling on the body to slowly release targeted areas.
Compression — while some parts of the body are tractioned in a pose, other areas are compressed. Most of the time in Yin Yoga gravity combined with body weight is the only force causing the compression but occasionally a sandbag or assist from the teacher can facilitate more compression.
A combination of tractioning and compression — this happens in poses like Broken Wing where the hand underneath the back is physically compressed by the weight of the upper body and the compression is resulting in a spreading of the tissues in the hand including a tractioning of the connective tissue in the joints.
Gentle joint movement — the joints are gently moved in all directions that they are naturally designed to move achieving a “gliding” effect and sometimes a release of air or the joint “popping”.
Bones — the skeletal structure of the body or foundation on which other connective tissue is laid. Made up of calcium salts deposited between collagen fibers, living bones are like living tree branches and can take a certain amount of pressure/stress without breaking.
To maintain bone health, regular exercise is advised to prevent degeneration (absorption of bone matter back into body). The long compressive stress that Yin poses apply to the bones stimulates a recovery response that will grow the bones stronger. Yin Yoga does a particularly good job of doing this for the lumbar spine which is often not sufficiently stressed in other forms of yoga and exercise (Bernie Clark, p. 213).
Other important components of a joint are:
Cartilage — similar in composition to bone but typically has more hydration and elastin fibers that make it more flexible. Cartilage supports weight bearing in the joints and adds structure in places like the nose and ears.
Synovial Fluid — is the lubricant in the joint capsule that allows the joint to glide in its natural range of motion. When a joint is stimulated through compression or tensile stretching (Yin Yoga) it stimulates an increase in synovial fluid (and chi flow to the joint). Synovial fluid can decrease with inactivity.
Hyaluronic Acid — is found in the synovial capsule of the joints. It can coil and uncoil and binds to water to maintain moisture in the joint. A lack of synovial fluid can result in joint pain and stiffness. It is now being used in medical and cosmetic applications.
FASCIA
Fascia — holds our body together in a cellular matrix. It’s the largest sensory organ in the body. Fascia is vital to the body functioning. It doesn’t have a set form, rather it takes on different forms as the body changes shape moment to moment and over time. Fascia is composed of collagen and elastin fibers. Some areas of the body have thick strong fascia with higher collagen content and other areas have fascia with more elastin fibers resulting in more pliability.
Collagen —a protein that forms a fibrous connective matrix. Like leather it is strong and somewhat malleable. It is found all throughout the body and is an “ingredient” combined with other substances to form bones, ligaments, and skin. There are 27 types of collagen that are found throughout different structures of the body. It is strong and resistant to stretching and can form in mats, sheets or cord-like structures (Bernie Clarke, p. 203).
Colla = glue, Gen = creator
Makes up a third of the protein in our body
Most important vitamin for collagen is vitamin C
Is highly conductive and is able to generate electrical currents
Electricity helps with bone growth and brain function
Collagen is laid down along lines of mechanical stress
Elastin — a highly elastic protein that stretches easily when stress is applied and resumes its shape when stress is released. Elastin fibers can stretch up to 150 percent of their normal length without breaking (Bernie Clarke, p.196).
Flexibility depends on the elasticity of the fascia which varies depending on how much of the fascia is composed of collagen fibers versus elastin fibers and how they are woven together. A body that has a lot of “fuzz” has fascia that has grown thick with intertwining fibers. Stressing the fascia encourages the fibers to rearrange and with a Yin Yoga practice it’s possible to permanently elongate a fascial pathway in the body.