A Case for Duration

Yin is all about duration. Remember “The alchemy of Yin is in duration, not sensation”? We’ve discussed the importance of coolness in body and mind and how these two things allow us to target plastic or connective tissues safely and effectively, but there are even more reasons to incorporate a duration practice. It’s awesome for recovery for athletes. It’s incredibly beneficial for older individuals who need a gentle approach but one that is still highly effective at improving balance, proprioception, range of motion and a variety of musculoskeletal pain issues. But here are a few more scientific reasons to employ duration. Understanding these will help you to emphasize the benefits of Yin through your selection of poses and how you direct your students in their holds.

Myotatic Reflex

Remember the last time you got a physical? The doctor probably tapped your knee with a little mallet and your lower leg jerked forward. She was testing your patellar reflex or myotatic reflex. When the mallet hit your patella it caused a mild but rapid stretch of your patellar tendon, which then transmitted the stretch into the quadriceps muscle on the top of your thigh. A special sensory component of the muscle called a muscle spindle detects this stretch and sends a message to the brain via the spinal cord. The brain sends back a message to the muscle to contract to protect the muscle and associated tendon from a potential overstretching injury. Even though it was just a mild stretch, the brain didn’t know that, so it just had to make an executive decision to lock down the muscle. When the quads contract the cause the knee to extend, or straighten, hence, you kick your doctor.

Why does this matter in Yin?

Because Yin is the ultimate tool for hacking the nervous system. By moving very slowly and carefully in our poses we can hack our nervous system into allowing a more yielding range of motion, by never triggering the myotatic reflex. Cool! This is why we keep sensation so mild. And why often after a period of ripening in the pose you will find that you can deepen your pose with ease, and it feels so good! For those of us who are already very flexible this may not seem like such a big deal but for those with limited range of motion it can be really helpful. If you struggle with major stiffness you know what I am talking about! The body and brain respond to habits, so the next time you go to stress the same area the brain might not send those signals to contract quite so early. This results in a greater range of motion over time. Potentially preventing injury or just improving movement and quality of life.

A Case for Duration

Yin is all about duration. Remember “The alchemy of Yin is in duration, not sensation”? We’ve discussed the importance of coolness in body and mind and how these two things allow us to target plastic or connective tissues safely and effectively, but there are even more reasons to incorporate a duration practice. It’s awesome for recovery for athletes. It’s incredibly beneficial for older individuals who need a gentle approach but one that is still highly effective at improving balance, proprioception, range of motion and a variety of musculoskeletal pain issues. But here are a few more scientific reasons to employ duration. Understanding these will help you to emphasize the benefits of Yin through your selection of poses and how you direct your students in their holds.

Myotatic Reflex

Remember the last time you got a physical? The doctor probably tapped your knee with a little mallet and your lower leg jerked forward. She was testing your patellar reflex or myotatic reflex. When the mallet hit your patella it caused a mild but rapid stretch of your patellar tendon, which then transmitted the stretch into the quadriceps muscle on the top of your thigh. A special sensory component of the muscle called a muscle spindle detects this stretch and sends a message to the brain via the spinal cord. The brain sends back a message to the muscle to contract to protect the muscle and associated tendon from a potential overstretching injury. Even though it was just a mild stretch, the brain didn’t know that, so it just had to make an executive decision to lock down the muscle. When the quads contract the cause the knee to extend, or straighten, hence, you kick your doctor.

Why does this matter in Yin?

Because Yin is the ultimate tool for hacking the nervous system. By moving very slowly and carefully in our poses we can hack our nervous system into allowing a more yielding range of motion, by never triggering the myotatic reflex. Cool! This is why we keep sensation so mild. And why often after a period of ripening in the pose you will find that you can deepen your pose with ease, and it feels so good! For those of us who are already very flexible this may not seem like such a big deal but for those with limited range of motion it can be really helpful. If you struggle with major stiffness you know what I am talking about! The body and brain respond to habits, so the next time you go to stress the same area the brain might not send those signals to contract quite so early. This results in a greater range of motion over time. Potentially preventing injury or just improving movement and quality of life.

Golgi Tendon Reflex

The Golgi tendon reflex does the opposite, It’s the pressure release valve. The golgi tendon organ is a proprioceptor that lives in the tendon, which is the tissue that connects muscle to bone. When muscles contract, they produce tension in the tendon as well .The golgi tendon organ records the change in tension, and the rate of change of the tension, and sends signals to the spine to convey this information. When this tension exceeds a certain threshold, it triggers the lengthening reaction which inhibits the muscles from contracting and causes them to relax. This basic function of the golgi tendon organ helps to protect the muscles, tendons, and ligaments from injury. The lengthening reaction is possible only because the signaling of golgi tendon organ to the spinal cord is powerful enough to overcome the signaling of the muscle spindles telling the muscle to contract. 

How does this play out in a Yin practice?

Well, imagine that your student is experiencing a muscle spasm. The muscles are contracting over and over essentially. As you know this can be very painful. The area is quite stiff. But if you apply a very gentle stretch, no higher than 3 on the scale for a long time, eventually the Golgi tendon will win. The muscle will relax! Why? Because the myotatic reflex is strong, but it doesn’t have great endurance. The Golgi tendon reflex on the other hand is a long distance runner. It can keep chugging along for quite some time and, like the proverbial tortoise and the hare, win the race. This results in a fragile peace in the affected muscle. It will feel like quite a relief, but the student will need to be so careful with the area until things have calmed down a bit.

Messenger Substance

Okay stay with me because this is really cool. Fascia can contract independent of muscular activity. A German study shows how the introduction of a “messenger substance” which is composed of stress hormones causes the fascia to contract (not that much but still). So fascia gets tighter as a reaction to stress! (maybe to staunch blood flow in the case of trauma). So remaining cool in your practice can actually cause your body to relax. Another important reason to cultivate an environment of introspection and a witness perspective.

Well who is that little guy (above)? It’s a proteoglycan! These are really important structures in the body since they are what holds the water in your body which is, after all, about 60-70% water. 

Hydration

Do you know what water is to the body? Youth. As we get older we lose hydration which is why we get stiffer and more brittle. So maintaining hydration is vital to improving our quality of life throughout our years. Here’s how Yin improves the hydration in the fascia.

Klingler and Schleip (2004) at the University of Ulm measured wet and dry “freshly harvested” human fascia and found that during an isometric stretch water is extruded, refilling afterward. As water extrudes temporary relaxation occurs in the longitudinal arrangement of the affected collagen fibres. If only moderate strain is involved there are no micro-injuries and water soaks back into the tissue until it swells becoming stiffer again. The key is to maintain a gentle level of stress. We don’t want to create micro tears in Yin since our goal is not to damage tissue but to encourage length through habit and practice. So Yin is THE practice for encouraging greater hydration in the body. And hydration after all is the key to supple, resiliant tissues.

Honestly

We’ve just barely scratched the surface here on how Yin works and why. If you, like me, love to know why. If you really dig the science stuff and want to totally overhaul how you think about your practice you might want to check out my full Yin hybrid training. The first module will be self guided online, on this site. The second module is live either online or in person. Learn more under the teacher training tab on this website.