Why? The Science of Athletics

140 WHY?-THE SCIENCE OF ATHLETICS as F1 and will go up again to j1. His training may then be maintained until he can go right through his original point of fatigue and finish with a slight rise of the curve as shown at P to f3. Now let us look at Fig. 15. z gnp A B c D E DiagPams ilfustPating D-rPaul Mar>tin's Leetu r>e.. Heart and Nervous Sys– te~ Potentials in Relation to Second Wind FIG. 15 The above diagram (Fig. 15) represents the natural potential · of the heart and the general nervous potential. The natural potential of the heart is _shown by the column A, of which p is the reserve built up by the process of training. Column B also shows the natural heart potential, but this is much lower because it is that of a man with a poor heart, and because that potential is so low the man in question runs a risk if he indulges in violent exercise. It is the heart of one of those foolish old athletes ~ho will run in veterans' races. If he drops dead an autopsy reveals nothing, but he has died because he has exhausted the nervous reserve of his heart. · When a man runs a race he also calls upon his general nervous potential, shown in column C by the bracket gnp, but when he reaches the critical fatigue-point in his race (point P in Fig. 14) he does not draw upon more than the shaded portion x of his potential in column D (Fig. 15) if he is in good training, and that represents only a small