Athletics of To-Day 1929

Some Points in Athletic Science 349 certain waste products of exhaustion are deposited in the muscle substance through violent exercise, and that massage directs them back into the blood stream and so relieves the muscles; but it is a change, through exertion, in the fuel that stokes the human engine that is really involved. As yet, we have not discovered the properties of all the chemical sub– stances that cause muscular contraction, and so enable us to perform feats of skill and strength. But we do know that muscles are made of protein, containing carbon, hydrogen, nitrogen, and oxygen, among other things, and that th y have as their fuel a starch-like substance, named glycogen, which is turned readily into sugar. Without this glycogen we should not be able to move at all, for it is what we use in doing our physical work. But when this substance is used it is not done with, since it is built up again from th sugar which comes to the muscle fibres through the blood, which in its turn collects the required sugar either from the res rve store in the liver, or from the intestines which absorb it in the digestion of food. Fatigue is probably caused by the increase in the muscle sub tance, by its own action, of lactic acid. The amount of such acid liberated corr sponds with the amount of work done and may be as much as one ounce in the ea e of a sprinter working at top speed ; but it may b , and is, remov d by increasing the supply of oxygen. Another neutralizing agent is the re erve of alkali, which is stored in the muscle substance for this particular purpose. It has indeed been suggested that the special facility for gr ater neutralization of acid in the mu cles is the quality that distinguishes th great athlete fronrr more ordinary nrr n. The 1 cov ry pr ess after exertion is curiously inter sting, for, although th lactic acid di app ars, it i found again in its original fornrr as glycogen. The glycog n ha created en rgy plus lactic acid in th work phas , while in the rest p riod of recovery the lactic acid pa s s back int glyc g n minu nergy through the introduction of oxygen and th help of the nrru cle alkali. We have seen already that everything goes on nrrore