Read up part 2 - extracted from -- Karate the art of "Empty-hand" fighting

Read up part 2 - extracted from -- Karate the art of "Empty-hand" fighting

Physical principles

Maximum strength

Any movement of the body depends on muscular expansion and contraction. There are many factors involved in exerting maximum force through control of these expansion and contractions, and only the most basic are listed here

1) Force is directly proportionate to the degree of the muscular expansion and contraction. This is the principles behind, for example, the coil spring – the more the coil is pressed down, the greater the force it exerts when released. Many parts of the human body operate in the same way.

2) The striking power of a force is inversely proportionate to the time required for its application. This means that in karate it is not the muscular strength used to life a heavy object that is required, but the strength manifested in terms of sped of muscular expansion and contraction. In the other words, force is accumulated in the form of speed and at the end of the movement; speed is converted into striking force. In scientific language, force equals mass times the square of the velocity.

Concentration of strength

To perform any kind of heavy physical work, concentration of strength is necessary. Even a great amount of strength will accomplish little if it is dispersed. By the same token a small amount of strength, properly concentrated, can be quite powerful. It is no exaggeration to say that the practice of most karate techniques is the practice of concentration of strength at the proper time and at the proper place. The following principles are basic

1) Other things being equal, the shorter the time a striking force is applied, the more effective it is. This element of concentration in terms of time is very important in karate, for it enables one to move immediately in to the next technique.

2) The greater the number of muscles brought into play in performing a given movement, the greater the concentration of strength. This force which can be exerted by the hands or feet acting alone is relative small; therefore, the musculare power of the whole body should be exerted in such a way that this strength is concentrated at the point of impact.

3) Maximum concentration of body strength depends on effective utilization of the resultant of forces produces by exertion of the various muscles. When the muscles are properly coordinated, the resultant force is greater; when they act in opposite direction, it is lessened

4) Concentration of strength depends not on simultaneous exertion of all the body muscles, bit on their exertion in the proper order. The muscles of the abdominal and pelvic region are powerful but slow, whereas those of the extremities are fast but weak. In order to concentrate the force of both sets of muscles, those of the abdomen and hips must be brought into play first, and this force transferred to the point of impact, either in the hands or feet. This account for the common saying in karate to move the hips first and hands and feet last.

Utilizing reaction-force

This refers to the well known principle of physics that to every action there is an opposite and equal reaction. This principle finds wide use in karate; for example. In punching out with one hand, the other hand is simultaneously withdrawn to the hip, adding reaction-force to the punching hand. Running or jumping is made possible by pressing downward with the opposite leg. This is important feature in karate where, for example, in punching, the rear leg is pressed hard against the floor, and the resulting reaction force is passed through the body and arm to the striking hand, adding force to the punch. In even more complex fashion, when the hand actually strikes the target, the shock of the blow is passed through the body to the legs and floor and then is reversed back to the punching hand, adding further force to the blow.

Use of breath control

It is well known that exhaling aids in contracting the muscles, while inhaling tends to relax the muscles. This finds direct application in karate, where the breath is sharply exhaled during the execution of techniques and inhaled after their completion.