Being a science sort of guy, I like understanding mechanisms of how things work. Tying in concepts from biology, physics, and neuroscience into martial arts training is something I can totally geek out to. In my mind, demystifying martial arts esoterica using science is a good thing. However, science is sometimes used incorrectly to justify certain principles and phenomena Fajin--the issuing of power--can be understood within the framework of sound science; it does not have to reside solely in the realm of qi, magic, superhuman abilities, or hand waved pseudo-science.
Here’s my attempt to properly apply classical physics to the often mysticized fajin.
Momentum ( p = m*v )
According to Wikipedia, momentum can be understood as the “power residing in a moving object.” From the equation p = m * v, we can see that momentum (p) is directly proportional to the mass (m) and velocity (v). In other words, the amount of power you can impart into your opponent depends on your size and how fast you can move.
You have limited control over the size part of the equation. You can only practically add so much lean mass before you hit your genetic potential or have to resort to bodybuilding methods like massive eating, steroids, and high volume weight training. While adding a lot of muscle mass is possible, it has a practical upper limit if you want to live a normal life and get enough quality skill training time. Of course, it is also possible to add fat mass, but that carries significant downsides like health problems and lugging around extra non-functional mass in your day-to-day life.
Between the two factors, velocity gives greater results for training time invested and can be directly improved through martial skill training. Velocity is partially improved by physical conditioning to improve muscular tone and biasing muscle fiber composition towards fast twitch fibers. It is also affected by movement skill, which is what martial skill training should directly improve. Attentive movement drills develop proper body alignment and coordination to improve movement efficiency. Concentration on grooving proper movement patterns improves neuromuscular efficiency so that the body is neurally ready to move, and unnecessary tension from incorrect muscle firing patterns can be relaxed so that movements can occur with fewer hindrances.
An analogy to training velocity would be a car. The physical aspect of training is akin to putting a more powerful engine into the car. This improves the raw ability of the car to go fast, but it is not the only factor in car speed. The car has to drive well in order to go fast: the transmission needs to be maintained to transfer power from the engine to the wheels, the wheels must be balanced and aligned, and the driver has to learn how to control the car speed so that he is not doing stupid things like stepping on the accelerator and brake pedal at the same time. Training movement skill is the equivalent of maximizing the efficiency of the transmission, balancing and aligning the wheels, and actually learning how to drive the car properly.
To a first approximation, learning to move properly increases the velocity portion of the momentum equation. There are of course other considerations and complications that can be added to this simplified explanation. The most important consideration would be that velocity is a vector quantity. It has both magnitude (speed) and a direction. Having speed builds momentum, but that is not sufficient to be effective. The velocity and momentum have to be pointed in the correct direction to affect the target. You can generate all the speed and momentum in the world and still be ineffective if you can’t aim well enough to hit your target. To fajin effectively, you have to be able to generate power and you have to be able to aim the power to hit your target.
Another issue is how the velocity is generated. In most untrained individuals, the speed of attack is generated by having a long travel path. In order to punch, they have to cock their fist back to get enough spacing to get sufficient velocity into their punch. It’s like their winding up for their Popeye punch. While this approach can work, it suffers from slow execution and telegraphing the attack. The opponent has plenty of time to counter when he sees you winding up for an attack. Also, in close quarters, being able to draw back to get enough distance to achieve higher attack speeds is often not possible. The attack velocity must be achieved over shorter distances. To continue the car analogy, you have to get your car from 0 to 60 mph in 5 seconds over 0.08 miles of driving distance instead of 10 seconds and 0.17 miles. To get more acceleration and achieve greater velocity and momentum over shorter attack paths, we must consider force production. Part 2 of the series will cover how force fits into fajin.