Some evidence indicates that an athlete after ten seconds of maximal exertion may not be fully recuperated in one hour. The trainer believes that after an athletic exertion recuperation is incomplete in twentyfour hours. It is believed that a runner cannot do his best daily, and some believe not even weekly. In hand ergograph tests in which small muscle groups are used and the work is carried to exhaustion, the average recovery in a group of subjects is 90 per cent complete in ten minutes and 95 per cent in twenty minutes. In our own work on the stationary bicycle, in which the subject does continuous heavy work as long as he can maintain the same degree of the work, my associates and I find that recovery in ten minutes amounts to from 45 to 80 per cent, depending on the subject; in one hour the recovery is practically complete. This type of work is rarely performed in industry. No physiologic studies have been made on the rate of recovery from the various degrees of neuromuscular fatigue which occur in different types of work that occur in industry. In the practiced and physically fit person it may be complete after thirteen hours, or there may be a fatigue residue that requires twenty-four hours or longer for recuperation