Some questions for you my dear reader...
What is the purpose of a yoga practice? Is it to be flexible? Is it to get new poses and advance?
I"m asking in a truly curious and non-condescending way, as I asked myself these same questions a few years ago and it really changed the way I related to my body. The questions arose after listening to an interview with yoga teacher and biomechanics educator Jules Mitchell about the Science of Stretching. This post is a salute to the enlightenment she provides about the often misunderstood concepts of stretching and flexibility. We're about to get scientific my friends, and I hope that it gives some context to the questions posed.
For the purpose of this post, let's get some terminology converted.
Physical flexibility >> range of motion
Tight/Inflexible >> limited range of motion
Open/flexible >> increased range of motion
I have more range of motion in my current practice than I had when I started yoga, and it allows me access to postures that I haven't always been able to do. However, I also have more physical strength in my current practice than I had when I started yoga, and I advocate that it is my increased strength that allows me access to my increased range of motion.
Our muscle tissue and connective tissue have a very specific purpose, to keep us mobile. We need to be able to walk, escape danger, and fight gravity. To move about our day, our brain sends messages to the muscles to do things like get out of bed, lift arms to hug, be in warrior pose. Our muscles send feedback to the brain in two categories: tolerance + intolerance. Though the categories are limited, the sensations within the categories are broad. Examples of sensations of tolerance include pleasurable stretch, power or feeling strong, and welcome discomfort (i.e. deep tissue massage). Examples of intolerance include reaching the edge of range of motion or shaking. It is at the threshold of intolerance where we are able to modify our relationship to a particular movement pattern and have the potential to increase strength and range of motion.
Increasing range of motion
A muscle doesn't stretch the way it feels like it does, like it's getting longer. Though over time with consistent practice we may be able to touch our toes more easily than before, our hamstrings are not elongating to allow this. What we are actually experiencing is increased tolerance to the stretching sensation of the muscle in that position. Other factors are at play such as tendons, ligaments, and facia, but in the interest of concision, we'll focus on muscles.
Let's think about a muscle like a wild animal. Animal sees a human and is rightfully cautious since human is unfamiliar. Animal keeps its distance to stay safe, able to escape if necessary. Over a period of time time, with consistent visits and repeated steady behavior, human shows animal that there is no threat and animal can put itself in increasingly vulnerable proximity to human. Eventually a deep trust is built and the animal is willing to be guided and pet on its belly. Our muscles and our brain have a similar relationship. When a muscle reaches the edge of a range of motion, it is experiencing an unfamiliar position and feels unsafe, too vulnerable to contract (escape) if necessary. Brain responds by reminding the muscle that it is safe by sending the message to engage in this position, effectively saying "see, you're ok". After consistently realizing that it can engage at a certain range of motion, the muscle is more tolerant of that particular position and allows more depth.
This is why I will always instruct a strength cue to the part of the body that is in the extended or "stretched" position. Encouraging the muscle to engage at as it reaches the edge of range of motion builds confidence in the vulnerable muscle. It may feel like it is decreasing the depth of the pose initially, but over time with repetition, depth actually increases.
Ever been in a lunge and your legs start shaking? Shaking arms in plank? Shaking muscles is the signal of intolerance under exertion. Similarly to muscles not feeling safe in a certain range of motion, muscles can also experience vulnerability when they have been asked to contract to the point they don't feel capable of sustaining, and will send the signal that it is time to stop. Often the primitive part of brain referred to as the "lizard brain" (amygdala) has built an association between the sensation of shaking with the need to resist or escape the situation. Our more recently developed reasoning (pre-frontal cortex) part of the brain has the ability to override this instinct instruct the body to remain at the tolerance threshold. This threshold is where muscle adaptation occurs, where strength is built.
Among about a thousand other reasons, this is why a consistent practice (of any physical activity) is so important. Repeated movement patterns make lasting impressions. It's also why some people experience confusion when they are proficient at one activity, expecting for that proficiency to translate to another activity, and being caught off when it doesn't come naturally. To them I'd say "give the body a break, it's unfamiliar"!
The symbiotic relationship between range of motion and strength is one of the things that makes the study of the body so compelling. There are always new thresholds to explore at every level of any physical practice. I really love looking at the body this way, as a partner, a teammate. Understanding the nature of our partner is essential to good teamwork, and just like any partnership trust must be built.
May we practice with purpose, with mindfulness to our movement, and with patience for our tolerance.