Why? The Science of Athletics

SOME MORE MATHEMATICS FOR ATHLETES 289 power in the longitudinal direction of the javelin and to send it away through the air in a straight line. Fig. 28, on page 200, shows the foot-work of the javelin thrower and also the line of direction to which he ·works in training ; and, as Valste has said in his "Instructions to Javelin Throwers", it is necessary that the javelin should be carried directly over this line during the last four throwing strides ; otherwise, if the point wanders to either side of the line, the thrower's power cannot be transmitted to the javelin in the direction of its own length. This is exemplified by his pictures in Plate 6. Despite the fact that I have quoted the Scandinavian axiom that the power must be transmitted longitudinally to the shaft, it seems to me that when the javelin is in flight the parabola of that flight must pass continuously through the actual centre of gravity of the weapon; for if the flight of the javelin merely follows the tip of the steel head the weapon will pitch too steeply and much distance will be lost. It is true that the angle of projection is one of 45 degrees, but it is equally true that the best and the longest throws show the javelin in flight travelling almost parallel to the ground. In point of fact, in very long throws, the javelin, having encompassed half its flight, seems suddenly to mount to a higher plane, upon which it sails on for a while before finally pitching earthwards as its impressed forces dwindle. A characteristic of a good throw is that the weapon descends on a gradual slant, entering the earth with the shaft almost parallel to the ground and the point only just breaking the turf. (See Fig. rog, Plate 23.) It is as true of the javelin as of the discus that one can throw further and with greater stability in flight when throwing against the wind than when throwing with the wind. Again, the major fault of the discus thrower is also that of the javelin thrower, in that the relaxing of the wrist to let the hand fall back during the delivery is a fruitful source of the javelin point tipping up, so that the spear flies through the air with the point too high, the T