Why do the techniques we are taught work so well?
interface between karate and physics. Are there any habits we've been picking up that actually make us less effective and should be corrected? What's a good scientific or quantitative way to assess these things? How should I strike to maximize the damage I will inflict, or to achieve the best balance of damage to time, or even to inflict exactly the right amount of damage and not do more than is needed? Etc, etc. With this post, I'm starting what will likely be a long-term investigation into some of these questions. I'll begin with some physics concepts and how they do and don't apply to what we do in karate Do.
I would argue that the main quantities that you want to look at to estimate the effectiveness of a karate Do technique are momentum, energy, and power (and concepts related to those, that I'll discuss in a moment).
Energy is a difficult term to define, because it can take so many forms. Let's go with "energy is the potential to cause change". If you're well rested and fed (have lots of energy), you can shovel a whole lot of dirt (or something), thereby rearranging the world around you. If you're exhausted, most of that dirt is going to have to stay where it is, because you don't have enough energy to move it. Similarly, a bullet that's traveling very fast (has a lot of kinetic energy) is going to rearrange whatever it hits more severely than one that's casually flicked off a table. Kinetic energy is equal to half of mass times velocity squared (so faster moving techniques have more kinetic energy behind them). Kinetic energy is definitely a useful quantity, but keep in mind that in a karate technique, there's a follow-through (or "impact" ) phase, where you're still using your muscles - there's more to this kind of impact than just the kinetic energy of your hand or foot right before it hits the target.
Power is the rate at which work is done/energy is spent: amount work done per second, or energy spent per second (depending on what exactly you're measuring the power of). Power is measured in Watts, where a Watt is a Joule per second.
In practical terms, an effective technique, I argue, is one that does a lot of work very quickly. So both work and power need to be as high as possible. Why is it important to do the work quickly? Well, because slowly pushing someone backwards and smashing their rib cage with a side kick could be doing the same amount of work. Mathematically, work is force times distance. W = F d. Work is pushing something some distance, but it doesn't factor in time at all. If you push on the surface of an object, that force will be transferred through intermolecular forces through the entire object, causing the whole object to move. If you knock hard on the same surface, you get a vibration (sound). There's a sharp disruption in the intermolecular positions, and that disruption propagates through the material as a vibration (i.e. a sound wave). Hitting even harder, you might permanently deform the face of the object which you struck. The same applies, roughly speaking, to an opponent's body. The same amount of work done over a longer time will tend to move th
Practically speaking, how do we increase work? W = F d.
The d is easier to deal with - one way to increase that distance is by following your techniques through - ending the punch a little ways into the target, rather than right on the surface. But what about the F? I just finished explaining why Newton's second law is a bit tricky to apply in this context, so how do we figure out F? Well, unfortunately, it's a function of how muscles work. This article will be followed up with a second part, after I've found some solid information about what the force curve for typical muscles looks like. That being said, we all know on an intuitive level what more versus less force feels like. Whatever the exactrelationship is between a muscle's exerted force and it's length, rate of expansion, and whatever else it may depend on, we all know what it means to apply more force with muscles.
tum after a collision, where momentum is the product of mass and velocity. So, the higher the impulse of a collision, the higher the end velocity of the opponent will be (this being reduced by their mass of course - heavier targets are harder to move).
your body into your techniques, use kime (which leads to quick, intense collisions) to cause damage. We can examine specific techniques in more fine-grained detail once we've got a quantitative grip on the behaviour of human muscles.
Until next time!
(Would be Nidan), holds an Honours Bachelor of Science (physics specialist program) from the University of Toronto."