of Combative Sport, Sept 2005
Judo: Maximum Efficiency and
the Body Mechanism
By Gunji Koizumi
Originally appeared in Budokwai Quarterly Bulletin, April
1945 to January 1946, pp. 20-21. Reprinted courtesy Diana Birch and the
Budokwai. Copyright 1946, 2005, the Budokwai. All rights reserved.
The most effective application of the body mechanism naturally is
governed by the dynamic law or the principles of leverage and balance.
For convenience, I will dissect and tabulate here the general
principles that apply to judo.
I have already described the general conditions how to keep the
balance of the body. [See "Twelve Judo Throws and Tsukuri," at http://ejmas.com/jcs/jcsart_koizumi_0302.htm.]
However, in applying a throw, you have to risk weakening the balance
and stand on one leg, so that you can free one side of your body which
is chiefly used in performing the act of throwing. This stance may vary
according to the nature of the action, but in the main it consists of
bending the ankle and knee so as to increase the "base" and lower the
centre of gravity. Then the balance is retained, through the changing
conditions in the stages of action, by subtle co-ordination of the
ankle, knee and hip joints.
- Unity of Action.
The side of the body freed for action
should be used as a solid lever. Merely stiffening the joints is not
sufficient; there must be co-ordination of all muscles. This
co-ordination is more possible if your mind is concentrated on the
abdominal action. When your mind is occupied with the action of the
hands or feet the lever will disintegrate; so will the effectiveness of
- Abdominal Power.
The abdomen does not assume any
importance in the Western conception of physical education, but in the
East it is regarded as the centre and basis of all physical and
spiritual power. Indeed, in judo abdominal power is the foundation of
all actions and movements. Therefore to cultivate fullness at the
abdomen (not strained contraction nor enlargement) and firmness of the
small of the back is a very important item in judo training.
As our common experience
demonstrates, the most effective way of using a lever or stick to pull
or push an object is to use it lengthwise. However, the contact and
stance of our body related to the opponent is such that the only way to
conform to the above principle is to curve our body from the finger
tips to the toes and use the body-lever in the line of that curve. This
applies to the local use of arms, wrists or fingers. Another way of
using the body-lever is as if it were connected to the hip joint of the
leg on which you are standing with a swivelling hinge.
- Two Wheels.
If you assume that you have made a contact
with your opponent in the usual manner and you have adopted the curved
posture, you will find that you have formed with the opponent roughly
two rings or wheels: one with the arms, another with the two bodies. To
follow the principle of using the body-lever as described above, the
way is to move the wheels as if they were rotated on an axis. According
to the purpose of the action the angle of the axis may change, but the
forms of the wheels must be retained from the beginning of the action
to the end of a throw.
These technical principles are the basis of and the vital factors in
the efficiency of judo. The skill depends on the ability to operate
them in the right direction at the correct moment.
To incorporate these principles into a single action in a
psychological moment is beyond mental control. Therefore through
constant practice the body must be trained to act automatically. In
general practice the sporting instinct certainly must be satisfied, but
the study of theory must not be neglected.
If in your effort you find your shoulders move upward the shape of
the wheels changes and the balance is weak, the opponent's arms or body
are in your way (assuming he is passive), and you should take this as
the sign of wrong movement.
There is no dogma with judo. Therefore a method cannot be said to be
wrong or right, but by testing it against the maxim "maximum efficiency
and minimum effort" it can be said that one is better than the other.
Thus judo is progressive and each one of us is a potential contributor
towards its further development. No one is perfect; all are fellow
pilgrims to unknown possibilities.