Why? The Science of Athletics

20 WHY?-THE SCIENCE OF ATHLETICS and quicker response to nerve impulses, while the un– trained muscle produced an altogether poorer efficiency. It then became apparent that the blood supply is the all important factor, and that very gradual training of the central nervous system produces the best type of that quick muscular contraction which is so important in sport. The system , by, and the speed at, which messages - pass to the muscles varies in accordance with the urgency, or otherwise, of existing circumstances. Exertion cau~es the creation of carbonic acid and lactic acid in the muscle substance, a man becomes short of breath, and the poisonous substances passing through the blood stream cause the nervous, system to notify the respiratory muscles that deeper breathing is needed to supply more oxygen for the eliminat~on of the poisons. That is the slower of the two methods. In the ot4er, where quicker action is called for, the message, or impulse, passes more rapidly along the unbroken living length of a nerve. A wave, as it were, passes along the nerve, but it is a wave of change, and not of anything material. If the back of a man's head and the back of his spinal ~ column were removed you would find the brain laid bare. At the top of the spinal column are the cerebrum and the cerebellum, each divided into right and left halves. In the spinal column itself would be seen the roots of the nerves, having inner -portions of grey matter, which act as "exchanges", and outer portions of white matter, which constitute the nerve-fibres along which messages are transmitted. It is by the gradual develop– ment and improvement of the "exchanges" that the human brain and nervous system have been built up, until what was mainly automatic at first has developed consciousness, understanding and liberty of action. The speed at which messages are transmitted to the muscles can be roughly reckoned, either by actuating the muscle of our frog (Fig. 1) by an electric current applied at two different points on the nerve; or-but