Accidental Kamikaze
Imagine I want to be a be a fighter pilot. I want to be a fighter pilot but I don’t enroll in the navy or air force, attend flight school, do physical training, flight simulations, or training exercises in a real fighter jet. Instead I watch videos of other fighter pilots flying with great skill, buy a bomber jacket and aviator sunglasses, then take a taxi to the the port where I board an aircraft carrier and announce I’m ready to fly.
Let’s also imagine for a minute someone is willing to entertain this, and lets me into a 100 million dollar plane. Maybe I know someone high up in government and am able to somehow convince them this is reasonable. So we head out to sea. I get in the plane with a seasoned pilot who handles the takeoff and ascent; then mid-flight he suddenly hands over control of the plane to me. I think to myself, “This is the moment; let’s see if I’m a fight pilot or not.”
I think we can all recognize that even though I am in a position to fly this plane, I don’t have any real capacity in this position.
This might seem like a fantastically silly scenario, but these intuitions regarding capacity seem to betray us in the context of mobility and pain. I think it’s easiest to start with the popular understanding of flexibility.
Fate and Flexibility
Most are under the following general impression. Flexibility is largely something you’re either gifted with or not. It’s also something gymnasts and dancers have miraculously. Maybe you can work on it a little.
When most people see someone move and think, “Wow she’s really flexible,” they imagine flexibility largely as some kind of hereditary trait. But the truth is genetics play a very small role in determining the range of motion of a joint (how far it can move), up to a certain point. When you get to the extreme end of the performance spectrum, genetics start to play a more decisive role in determining the hard stopping point of a joint. But leaving these extremes aside, general flexibility really isn’t determined by accidents of genes.
How people think about flexibility is important, because these perceptions will play out in how they approach flexibility in practice. And the perception above basically plays out in practice as, “Let’s see if I’m a fighter pilot or not.” They try a couple stretches, compare themselves to others in the gym, group classes, or online, then they make a binary decision: “I have a gift for this,” or “I must not be flexible.” And if it’s true that flexibility isn’t largely genetic, you can guess on which side of that dichotomy most would fall.
The second popular perception of flexibility is that it only refers to “how far” a joint can move, regardless of how it gets there, or what it does when it’s there. For once, this popular notion is actually correct; flexibility is limited purely to the range of a joint’s motion (ROM). But in my view this is also why the concept of flexibility is itself incomplete. Because in all practical cases, how far a joint moves is not the only factor that matters to us.
Mobile Matters
What we also care about in nearly every case, except when someone is under anesthesia or otherwise unconscious, is how a joint enters and exits various positions and what we can do while it’s there. This is for two key reasons.
Whether you are entering a joint position passively or actively, if you are conscious your central nervous system (CNS) is involved. This means that the joint isn’t simply material moving through space. The nervous system—which is integrated throughout the tissues of your brain and your body—is having a “perception” of what is happening as these materials move around. And that perception greatly affects the joint’s ability to move—now and in the future. Until a joint hits the hard limit of the tendons, ligaments, and bones, what determines the limits of ROM is the nervous system. And the nervous system “decides” what it will allow based on its past perceptions of what you have done, and what it “thinks” is possible for you without risking tissue damage. We’ll come back to this “perceived tissue damage” concept in more detail in part II of this article.
We care about capacity. It’s a rare case that someone truly wants to be merely passively flexible. Maybe dancers, contortion artists, and gymnasts can be exceptions to this—because for the sake of aesthetics and performance in some movements, they might only care about moving the joint into some positions passively. Examples of this would be a contortionist’s deep back bends, or the highest position of a ballerina’s grand battement. Long-term this comes at some expense, of course (we’ll also get to the reasons for this in part II). But for almost everyone else, when it comes down to it, they care not only how far a joint can move but how safely it can move without pain and what that joint can do in those positions. They say they care about flexibility, but really what they care about is mobility. And it’s only the seduction of appearance that would convince them otherwise. While flexibility refers merely to the ROM of a joint under any conditions, mobility is a factor of both ROM and the capacity to generate force in any given position or direction in that range. Tell someone he has three choices, and all of them will be pain-free. Option one: his shoulder joint can move into a fully flexed overhead position (armpit fully open, and 0º angle between upper arm bone and torso), but only passively—meaning he or someone else has to move his shoulder into this position with outside force. Option two: he can move his shoulder into that same end position actively, with no help from any outside force. Option 3: he can move his shoulder into this same end position actively, and do so from any direction while holding a 5kg weight. Nobody in their right mind would chose option one. And each option after that only increases in attractiveness. The reason for this is simple: we value capacity. The ability to do something in a position is worth more than merely being in the position. We see this very clearly when faced with flying a fighter jet. And yet, this same intuitions seems to slip away when it comes to piloting our own physicality. Further: the nervous system agrees with us about the value of capacity, and even sees it as a potential threat to the integrity of our tissues when we chronically enter positions without the capacity. The way it expresses this perception of threat is through pain.
A Few for Review
Before moving on to part II, here are some reviews and takeaways.
The ROM of a joint is mostly not genetic or hereditary. It can, and in almost every case must, be practiced.
Believing joint ROM is mostly heredity is unhelpful at best, and goes against our better judgement in most other contexts. In this regard, it’s wise to be aware of our poor intuition in matters of mobility.
Wearing aviators and a bomber jacket in a jet do not make a fighter pilot; similarly, it’s silly to expect the body to do anything beyond the scope of what it has practiced.
The most common definitions of flexibility are restricted only to joint ROM.
Mobility is a factor of both ROM and the capacity to generate force in any given position or direction in that range. For this reason I see mobility as a superior concept to flexibility, for movement purposes.
We place a high value on capacity, not only positions.
Chronically entering positions in which we have little capacity to generate force increases the probability that the nervous system will “decide” there is a threat of actual or potential tissue damage.
The nervous system communicates this perceived threat through pain.