Why? The Science of Athletics

CONSIDERATIONS IN RELATION TO COMPETITION 131 combustion of the gases in the blood, just as there is in the engine of the automobile, and the gelatinous muscle– substance, equally with the oil of the motor-car, has to be made less viscous before either will function as effectively as it is capable of doing. Stretching Exercises are Essential The purpose of the athlete usmg stretching exercises as a part ofhis limbering– up ritual is twofold, for the practice of movements of this kind increases efficiency in the first place and, in the second, serv€s as a safeguard against possible injury. , We have heard already how a muscle consists of large numbers of fibres packed in bundles, each fibre being composed of many fibrils which probably supply the source of that power we so little understand, i .e. the power of contractility. We know that these substances are of a jelly-like nature and become less viscous when warm, and we know that a muscle terminates in tendons or sinews to afford its means of attachment and insertion to the part to be moved. The delicate nature and diminu– tive proportions of the fibres and fibrils have also been explained, and it is the tendons of all the fibres in a muscle which are joined together at the end to form the tendon of the main muscle. Even so, the tendons which attach the musde to the bone are neither very large nor tremen– dously strong, except in proportion to their size, and much of their efficiency depends upon their elasticity at the moment when called upon to perform a specific task. When the body is cold the tendons are less resilient and therefore more brittle. The stretching exercises, which the athlete should perform as part of his limbering– up process, increase the elasticity of both tendons and muscles and thereby lessen the danger of injury. After a muscle has been stretched a number of times, moreover, it will contract more powerfully. It may be said, there– fore, that the stretching exercises increase the contractility of the muscle. It is a fact, also, that the movement of joints to