Physics of Fajin, Pt. 2

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, 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, and (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.