We are born with a natural predisposition to use force against force, but this usually gives the larger, stronger or younger individual the advantage.
More efficient and adaptable is the use of power instead of strength . Power is the sudden release of focused and coordinated action and can be enacted by anyone at any age or size when properly trained. Taking the mechanics of typical strikes in comparison to power based strikes we can then reverse engineer these action for our use with Kyusho.
Now it should first be made clear that the more actions that are brought into a motion the more diffused the energetic transfer will be. For example (using a typical striking action), when the arm is deployed if there are other body movements this will unbase the launch platform and weaken that type of strike.
However even more efficient than power is focused power where all kinetic energy is sharply focused on a smaller weaker area... From a smaller action.
But even this can be further refined with focused penetration and other physical factors. The caveat is that each additional factor or attribute must be learned and trained to become of worth under a stressful situation as some if not all attributes realize a degree of failure during high stress... and why we must train for it.
Kyusho always looks easy, but there are numerous attributes for real application that must be trained in terms of power and trajectory for kinetic energy transfer into the target.
First we need to utilize a short burst of power as the longer the distance the more indirect the focus will be. As an example, when you extend the arm from your body to the opponent, several muscle groups are charged to accomplish this extension. This involves several antagonistic muscles that pull individually as well as in conjunction, thus causing the flight path of the hand to waiver as each group relinquished or acquired the next stage of that extension. So in slow motion you can see the extension as a multi curved path as opposed to a direct one directional path. This in turn dilutes the power or energetic transference in alternating trajectories as opposed to directly into the target.
If the arm is already partially extended and then deployed, or if the arm is extended in a relaxed manner before the power is increased, the antagonistic muscles are not as influential. So as we see in Wing Chun, Ba Gua, Sanchin, etc. as exaple, the arms are always extended so as to capitalize on short range power as opposed to full range strength. This is depicted and hidden in the Bubishi with the use of the 6 JI (energy, wind) hands.
Another power influence can be realized by looking at the difference torque can make inserting a nail or screw into a wooden object. If you have to initiate a strong power to penetrate the wood, the hammer hitting the nail must travel a long distance to achieve that power. The distance takes great aim and control as well as stable target to fully achieve so that the nail penetrates straight without tilting or bending.
However if we use a screw, we are already close and apply a short but powerfull twist to achieve penetration even on a less stable target. Sight, aim, trajectory factors are now unnecessary and the additional power is developed through the torque of the wrist into the final weapon.
This type of power is generated in the wrist more than the arm so as to maintain the straight and relaxed trajectory for greater accuracy.* This is the final twist of a Karate punch, the turn of the hand in Sanchin or Ba Gua.... in Wing Chun's final handset "Bui Jee", we see the strange actions at the beginning that looks and is mostly interpreted as finger tip strikes as they rapdily shift side to side as well as up and down. However this is more accurately conceptualized as a rotating wrist action for the short explosive torque generated power. In the Karate punch the twist is still widely used, but not as it was in times past. If we watch the old films of long past Karate men, their actions are totaly relaxed with emphasis more on the hand action as opposed to the arm. Many state it was a performance of an old man, or that they were sloppy or bored, however they were working correctly so as to utilize power over strength.
In Kyusho, this is the proper way of working the targets with torquing power (which also develops other necessary qualities to the point, we can be the focus at a later time). As always the Kyusho-Ka looks relaxed and the strikes look week (just like the old films of the Senseis), it is mis-understood by most as fake or disingenuous... however it is what was originally in the forms as power.
*As an experiment, stand at arms length from a light switch. With hand by your side and as fast as you can reach out to flick the switch down with your index finger. When you move the arm as fast as you can you will miss the switch more tha 50% of the time. You will see the antagonistic muscles have actually pulled the arm off course or off target and why many people miss the Kyusho points in training when the first start. Now with hand in the same position just extend the arm and save the speed for the flick of the switch and you will now achieve 95% or better. This is the correct way to influence the Kyusho Point as well.
So when you see a Kyusho-Ka working a standing KO, they are in reality practicing this beginers lesson on accuracy, energetic transfer via torque and the application of power.