Physics of Explosive Energy | Fajin

Johnny Kuo  |  I-Liq Chuan

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 TWO

You don’t have to be a rocket scientist to figure out fajin, but you might want to use a little rocket math to understand it. The force equation is a fundamental relationship for understanding how rockets get off the ground.  In the last blog post (Part 1), we left off mentioning how we need acceleration to generate enough momentum over short distances.  For our purposes, we can use the force equation to analyze how it is possible to generate enough velocity and momentum for a short distance attack.

Force (F = m * a)

Two things affect force: the mass of an object and the acceleration of the object. Bigger objects can impart more force (i.e. a sledgehammer hurts more than a BB), and faster acceleration correlates with greater force (it takes more force to go from 0-60 in 5s than 10s). To get the necessary velocity to impart maximum momentum, we need to consider acceleration. The faster the acceleration, the better the ability to achieve higher velocities over short distances and the greater the likelihood of generating higher momentum with an attack.  To get fast acceleration, we need to generate force.

When we discussed momentum, more mass was advantageous to having greater momentum. However, when considering force, more mass is not necessarily an advantage. Getting more mass in motion requires more force just to break the inertia of the mass. Adding more lean body mass in the form of fast-twitch muscle fibers is akin to adding a bigger engine which allows more force generation and greater potential acceleration. Adding fat mass on the other hand is equivalent to putting a heavier chassis on the car; it increases momentum but may end up reducing the acceleration potential since fat mass has no force generation and increases inertia. The last part of the physical aspects of force generation would be the ligaments and tendons, which act as the transmission gears of our metaphorical car. The gears have to be strong enough to handle force of the engine and transfer that force to the wheels.

All of the physical factors can be improved (more muscle, less fat, more resilient ligaments and tendons) through physical conditioning. However, as was the case in our momentum discussion, there are practical limits to the physical conditioning. Baseline effective physical fitness can be achieved relatively quickly, and more gains in acceleration potential are more likely achieved through skill training.

Force generation depends on the practitioner’s movement abilities. Efficiency in body movement and proper body mechanics have a significant effects on force generation. For the purposes of discussion, we can consider three trainable components of movement ability:

1. alignment
2. relaxation
3. joint coordination

One of the first things the practitioner should strive for is proper joint alignments. When the joints are positioned properly, less muscular exertion is needed to keep the body structure organized and the more potential muscular activation is available for force generation. Establishing the proper body alignments is a prerequisite for the muscles of the body to relax and thus be more available for force generation. A prime example of this would be the stacking of the body over the feet so that the minimum effort is wasted standing upright. Other examples would be keeping the elbows behind the wrist or knees aligned to the toes during force generation. Poor positioning of either of these joints results in extra muscular effort being spent just stabilizing those joints.

In addition to allowing greater potential force, relaxation also allows more efficient use of force. An untrained individual (particularly with the modern sedentary lifestyle) often has several movement dysfunctions. The proper muscles are not sufficiently activated, the body alignments are off, and extraneous muscles are tensed to compensate for improper body mechanics. The extra muscle tension often retards the desired force. The extra non-functional muscular tension is like driving a car with the accelerator and brake pedals simultaneously pressed. A lot of force might be generated, but the unnecessary tension means that different forces in the body are working against each other. An example of this would be throwing a punch with all the muscles of the upper body tensed at the same time. It can feel like a lot of effort is going into a super strong punch, but because the muscles are not contracting and relaxing in the correct sequence, they end up working against each other and making the punch weaker. When the unnecessary tension is taken out of the movement, the generated force is applied more efficiently towards the desired movement.

Finally, joint coordination plays a crucial role force generation. To achieve maximum acceleration, we want to be able to tap into as much muscle as possible to generate the maximum amount of force. If we rely on only muscles local to one joint for movement (let’s say the elbow for a punch), then the amount of force we can generate is limited to strength of only a few muscles which may not even be all that strong. What we can do instead is use multi-joint movements to draw on muscles from all over the body, particularly from the strong muscles of the legs and hips. This requires that the joint alignments be correct and that the movements of each body segment coordinate properly with the other body segments. When the coordination is correct, the movement becomes like a chain that is whipped: each link transfers power to the next segment until the sum of all the individual forces is manifested at the end of the chain. If the movement is uncoordinated, the forces do not sum together and the chain flops in a disorganized fashion.

One of the purposes of the skill portion of training is to develop movement quality.  When we can leverage proper body alignment, relaxed movement, and whole body coordination, we can achieve sufficient force production to accelerate our attacks over much shorter distances than would be possible otherwise.

Johnny Kuo

originally posted at mindbodykungfu.com on 9/1 & 9/9/2011

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