In the older texts it has always been stated that you can attack nerve, blood, breath, muscle and bone.
For years Martial Artists concerned themselves with breaking bones with sheer power (thus the breaking skills that appeared). Next the Blood with chokes, but this is a very small portion... what we teach at higher levels. It is the same with the breath by striking the solar plexus... there is way more ways to do this as well. Evolving further, the nerves, blood, breath with Kyusho... this got rather extensive as you are bearing witness to now. And by the way the least amount of force and observable damage compared to the other attack methods. The last is the muscle, which can be affected with the nerve, or Goldi Tendo Organs (GTO) and the Muscle Spindle Cells (MSC).
The Article from 2005 Budo International Magazine:
The study of Kyusho includes dysfunction of several body functions such as neurological, vascular, respiratory, digestive and other functions including the function of the Muscles and Tendons. Ancient texts also describe these muscle and tendon attacks in general, but never do they get into the specifics of what occurs or the actual way to accomplish this on the human body. Besides the physical destruction of ripping, puncturing or otherwise destroying the actual structures, there is a non-damaging neurological method for successful results in this regard.
There are two types of neurological mechanisms called mechananoreceptors: the “Muscle Spindle Cell” (MSC) and the “Golgi Tendon Organ” (GTO), often referred to in Kyusho as the Golgi Body. Every muscle has both types for the safe and coordinated interaction of contraction and expansion, with their function being to keep the muscle from being damaged. By correctly attacking these receptors, we can therefore disrupt the normal function and capability of the structure and therefore the body’s ability to move or use them.
So we have two structures that guard the muscle, the MSC function is to make sure the muscle doesn't get damaged by being overstretched and the GTO function is to make sure that the muscle isn't torn from its origin and/or insertion by a sudden increase in tension". That's why the GTO is in the tendons (to keep the muscle from being torn from the bone) and why the MSC is the belly of the muscle (to keep the muscle from be "shredded" from being overstretched). Without the MSC you could have muscle damage but will still be attached to the bone at its origin and/or insertion. Without the GTO you could have the muscle torn from the bone at the origin or insertion but the belly of the muscle would not be in itself damaged.
The main structure that will cause physical dysfunction of a tendon (the fibrous cord of tissue that connects the end of a muscle to the bone or other structure) is the GTO. Every muscle has one end that is firmly attached to bone called the origin (or the end of the muscle that stays in place or is rooted). While the other end of the same muscle is attached to another bone called the insertion and can be thought of as the structure that will pull the other bone closer. For example, when you contract the biceps, you pull the lower arm toward the upper arm. The muscle ends in tendons and the tendons plug the muscle into bones. This is where the GTO comes into play.
The Golgi Tendon Organ is in the actual tendon itself with the sole function being to measure muscle tension. What is happening is that a group of individual muscle fibers are plugged into a GTO like several power cords plugged into a single outlet. The GTO monitors the pressure on that group of muscle fibers giving your brain feedback on small portions of the muscle and it’s function. This allows the brain to not only monitor how the whole muscle is doing but also each of the individual parts of that muscle. When the GTO senses too much tension (contraction) on the muscle it sends a signal to the cord that causes the muscle to relax to reduce the tension or possibility of damage.
The GTO is activated by a significant increase in tension so the best method of attack to a GTO is a deep and rapid rubbing action simulating a quick and potentially damaging occurrence in the muscle. It is at this time that the muscle completely relaxes also causing the antagonistic muscles also relax. The rubbing action must mimic the direction of the tendons contractive and expansion direction (in the direction of the connection from muscle to bone as the same reactions will not occur if attacked in a perpendicular direction).
As an example by correctly activating the GTO in the elbow, at the base of the triceps, all of the muscles in that particular arm will be relaxed as rapidly as the attack. This can also be used very efficiently to dislocated joints as the muscles and tendons can no longer contract and hold the joint firm (when practicing this serious and permanent damage to the joint can occur. This level of destructive capability is the underlying reason the demonstrators of Kyusho use very little strength and effort, so as not to cause damage and why many believe the recipient is faking as the dysfunction belies the perceived need of power). Another physical manifestation in this is the dysfunction of both legs as well that can be explained as follows: As the brain sends an electrical signal down the spine to maintain strength in the leg muscle, when the severe electrical message is sent from the arm to the brain this urgency supercedes the electrical message from the brain to the legs and therefore they dysfunction as well. Not a bad response for such little effort, total body dysfunction with a simple little rubbing action, such is Kyusho and why it may appear false to the unknowing viewer.
Another example would be a rubbing action on the Quadriceps or Patella tendon (an extension of the Quadriceps Tendon). By a deep and rapid rubbing action up and/or down he length of the tendon, the complete leg will relax and the knee joint will hyper extend backwards from lack of muscle tensing capability to keep it in place. This can be done with a forearm from a kneeling position, or if you have hold of the ankle with one arm and use the other for the rubbing action. Or if you are using your legs, a sliding kick against the tendon or even with an object such as Police Baton will cause the same dysfunction.
One more example would be in the Achilles (Calcaneal) Tendon just under the Calf (Gastrocnemis) Muscle. Many grapplers use this for an extremely effective ankle lock submission as well, due to the painful nerve reaction. The best manner to cause the inherent muscle weakening is to not simple push into this sensitive spot, but to do so with a deep rubbing action. Also remembering that the quicker the rub, the more intense the pain, dysfunction and physical reactions will be.
The Muscle Spindle Cells (MSC) are actually in the belly of the muscle itself and monitor the stretch put on the muscle (they more accurately monitor the length of the muscle). So if the muscle is stretched too far, the (MSC) send a message to the spinal cord which relays a message back instantaneously to cause the muscle to contract (shorten) so the muscle isn't damaged by being overstretched. It may sound the sound the same as the Golgi Tendon Organ but it's not. The major difference between the GTO and the (MSC) is that the Muscle Spindle Cell causes the muscle to contract to keep the muscle from overstretching. Whereas mentioned, the GTO cause the muscle to relax to reduce the tension on the affected muscle.
The MSC is activated by the muscle being overstretched so again he best method would be a rubbing stretching action, as in the GTO, however with the opposite reaction of muscle contraction. And whereas the body of the muscle is larger and more pliable, a sharper more penetrating action is needed compared to the GTO. So the correct weapon is a bone structure that will efficiently attack the MSC. Also the larger the muscle body is, the more force and penetration it will need to get the desired dysfunction and or reaction.
What happens when the MSC is attacked well is that the particular muscle sharply contracts. This in turn can affect all attached or connected structures and resembling an implosive action. Lets say we attack a biceps with a knuckle punch directly to the center, but with a slight dragging action. This will first rapidly stretch the muscle fibers causing the MSC force the reactive muscle contraction. This will quickly pull the forearm in at the same time as the deltoid, latissimus and pectoral muscles also contract causing the body to cramp on the side and front as well. This allows us unrestricted access to the back of the head and body.
Taking the latissimus muscle for another example, by striking straight in pain will of course be felt, but by adding a dragging action to the strike as if to mimic an overstretched muscle and therefore the MSC, a much more dramatic action occurs. First a sharp contraction of the muscle followed by paralysis and again exposure of vital points on the head, neck and back of the opponent.
One more example is the large muscle group of the Quadriceps, located on the front of the upper leg. By striking in at a 90 Degree angle into the bone, pain and dysfunction will naturally occur, but it will be significantly enhanced by dropping down at a 45-degree angle on the muscle. This will again activate the MSC by simulating the dangerously overstretched condition of the muscle. This contracts the whole quadriceps, so fast that it can easily cause a hyperextension of the knee, severe pain and paralysis of the entire leg. Obviously caution is needed here, but even more so as the vascular tissue can also be damaged leading to varied states of hematoma, not necessarily on point of impact. Meaning the blood leaked by the damaged blood vessel can pool elsewhere on the leg, clotting and potentially causing further health issues for the recipient.
By knowing and continuously recognizing (through practice), exactly how the opponent’s body reacts, moves and dysfunctions will increase your readiness for many possible needs. Strategy becomes more the focus rather than that of defense, or dealing with unknown situations which in turn will lead to increased stress and less physical control. By knowing and completely understanding the human reactions with each move and exploiting it in strategy, you will ultimately gain advantage in personal defense.
All of the Tendons and Muscles in the body can be effected as mentioned, not limited to the very few discussed. They also are in close proximity to nerves and as such by attacking either the Muscle Spindle Cells or the Golgi Tendon Organs; you may also be affecting proximal nerve structure. One more note is that since each of these methods do send nuero messages even without a proximal nerve being affected (they are spinal cord reflexes), that they indeed further weaken or setup all other nerves for follow-up if needed.
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