Why? The Science of Athletics

HUMAN MECHANISM must husband their efforts if they are to return the optimum time for their particular race. Athletes become tired for two reaons. Firstly, the sprinter very quickly creates what is termed an "oxygen debt" ; and secondly, the valuable glycogen inside the muscle-fibres is turned intG poisonous lactic acid, the muscles become tired and stiff, dwindle in power, and finally refuse to function until the lactic acid has been turned back into glycogen during the recuperative pro– cess of rest. Oxygen Debt We have seen already that a very violent effort, when sustained, may create a situation in which the heart, lungs and blood may not be able to cope with the demands made upon them by the muscles. Working to the statistics provided by Lowe and Porritt, we can calculate that a sprinter running a hundred yards in IO secs. would need some 6 litres of oxygen, which is the amount required by a man walking a mile in half an hour, while experiments by Professor A. V. Hill have proved that a good I mile runner moving along easily at IO miles an -hour would require 20 litres of oxygen, whereas a bad, untrained runner, even if he could run a mile in 6 mins., would need 54 litres of oxygen. Fwm this it will be seen that the thing to be decided in assessing the prospects of a runner is the economy with which he runs. In this connection, much depends upon what his oxygen income is, and what amount of oxygen credit he is able to establish. Now an athlete can in several ways make use of total oxygen available during both effort and recovery. From what has appeared already it will be obvious that the sprinter in his brief, violent burst of speed can com– mand next to nothing in the way of oxygen income. It is not, in fact, beyond the bounds of possibility for a sprinter to run his 100 yards without breathing. It is obvious, however, that the duration of an effort and the length of time necessary for recuperation are dependent equally