Page:Popular Science Monthly Volume 53.djvu/203

Rh, the muscle will then liberate energy for a long time. This latter condition is what we call endurance.

The power and endurance of the human machine is limited according to our understanding of the above facts, and also our recognition of its slowness in getting started. Like any other ponderous and intricate machine, the body requires time to get in harmonious working order. The brain, nerves, heart, and skeletal muscles must be given some warning of the work they are expected collectively to perform. Ignorance of this fact has broken down many a young man who aspired to honors on the cinder path. The necessity of getting all the parts of the body slowly in working order is well understood by trainers and jockeys on the race track, as is evidenced by the preliminary "warming up" they give their horses, although it is doubtful if the trainers could give any physiologic reason for this custom.

Of the substances supplied to the muscle by the blood, oxygen is one the want of which is soonest felt. The muscle contains within itself a certain store of oxygen, but one which is by no means equal to the oxidizable substances. The muscle's activity is dependent to a great extent on the character and force of the blood flow through the muscle. It must be clear of the waste products, as well as containing sufficient oxygen to continually keep up a renewal of energy. From what has been said it will readily be seen that the result of a muscular task which an athlete wishes to perform will depend primarily on his muscular bulk and on the condition of these muscles, and the rate at which he expends his capital; the test of his endurance will depend upon the condition of the other parts of his body, and how thoroughly and rapidly they will carry off the quickly formed poisonous products and supply fresh ones.

Nineteen pugilists have died in the ring the last seven years. Not one of these deaths was directly due to the force or severity of the blows struck, but because the fighters were "out of condition" The waste products caused by the rapid muscular work accumulated in their bodies, and, forced to go on with their exertion, they dropped exhausted to death—poisoned by material of their own manufacture. Less attention paid to mere muscular exercise, and more to the condition of the blood and other parts of the human machine, would have brought different results. These facts impressed upon a certain class of athletes would be of great moral and social advantage to the world in general. It means that these individuals must have fresh air to live in, clean skins, good, substantial food, a fixed number of hours for sleeping, and avoidance of stimulants. If it was well understood that no man could go into the exhibition ring, or into any contest requiring physical exertion, unless he could show,