It has been almost a year since we’ve been able to train “normally”. Last summer we trained in the park, and we briefly managed to run some distanced indoor sessions in October last year, but regular sessions are starting to become a distant memory. In the meantime I’ve been using my time learning more about teaching and running sessions, and planning out some changes to how we do things in the dojo. With no kendo to talk about, I plan to use this blog to share some of my thoughts and discoveries.
This time I’m talking about myelin. I’ve been re-reading a book called The Talent Code, which discusses the physiological mechanism behind “skill”. A substance called myelin features heavily.
Myelin is a fatty substance that lives in your brain. It is the reason that when you’ve practised an action a lot you can do it faster and more consistently than something new. When we perform a certain movement, neurons fire to carry the signal from the brain to the muscles. Every time that happens, a thin layer of myelin wraps around the neuron – the more that movement is performed, the more myelin layers we get. It acts like insulation around a wire, allowing the signals to travel faster and more strongly to the muscles. When we build muscle memory, what we’re really doing is growing more myelin.

But we can’t just repeat the same motion hundreds of times and expect to become an expert. It’s like going to the gym every day for years and always lifting the same weight – you’ll improve at first, but eventually you’re just going to stagnate. If you want to improve, you need to constantly give yourself a challenge to adapt to. So how do we maximise the skill growth we get out of our training time?
We need to make sure we’re always working near the edges of our abilities if we want to make the most of our time. I like to aim for a 60% success rate when I’m doing drills. That is, if we do a particular move 10 times then I should “fail” at 4 of them. If I succeed all the time, I’m not learning. If it’s too difficult, I probably don’t have enough context or underlying skill to understand what I’m missing. And this can be done with any drill or exercise. I don’t have to always be doing techniques that I’m ok at but not great and chase that 60% success rate. If we’re just doing men cuts on a partner, I can get myself to that 60% zone by being picky with my own kendo. I choose one element of a “good” men cut and I focus on that, and set myself a high standard for what I consider to be acceptable. A high enough standard that I can only reach it around… 60% of the time. The beauty of this is that you don’t need anyone’s help for it, it’s something you can do all by yourself. And once you’ve got the habit there, you’ll find your training becomes so much more effective every single session.
One other way we can help build skills is by a process known as “chunking”. Instead of trying to learn a new exercise or technique in one go, we break it up into chunks and get good at them. Then, we learn how the chunks fit together and hey presto, we have a complete technique. We’re focusing the myelination into specific areas one at a time, rather than reaching too wide from the start. For example when we learn kiri-kaeshi for the first time, we learn sayumen and tsubazeriai separately first, before joining them up and learning the pattern. We don’t try to learn all of the parts at the same time as learning the sequence, we take it one bit at a time and join it up at the end. This is something I try to take into account whenever I introduce a new exercise to people.
Next month, I’ll talk about a problem-first approach to training and what that means.