Actual instances prove that great increase of work and results can be secured by outside stimulus and by conscious effort.

If there is one place where the limit of exertion can be counted upon, it is in an inter- collegiate athletic contest. While taking part in football games, I frequently observed that my team would be able to push the opposing team halfway across the field. Then the tables would be turned and my team would give ground. At one moment one team would seem to possess much superior physical strength to the other; the next moment the equilibrium would be changed apparently without cause. Often, however, the weaker team would rally in response to the captain's coaching. On the field a player frequently finds himself unable to exert himself. His greatest effort is necessary to force himself to work. In such a mental condition a vigorous and enthusiastic appeal from the coach may <p 10> supply the needed stimulus and stir him to sudden display of all his strength.

I recently conducted a series of experiments on college athletes to determine whether coaching could actually increase a man's strength when he was already trying his ``best,'' and whether he could continue to work after he was ``completely exhausted.'' I put each man at work on machines which allowed him to exert himself to his utmost and measured his accomplishment. While he was thus employed, the coach began urging him to increase his exertion. Ordinarily the increase was marked—sometimes as much as fifty per cent.

Again, when the man had exhausted himself without coaching, the extra demand would be made on him; usually he was able to continue, even though without the coaching he had been unable to do any more. There was, of course, a point of exhaustion at which the coaching ceased to be effective.