Abstract
1. Recently, the mental work is greately needed in addition to the physical work for umpires with the progress of playing technique. It is supposed that the visual sense plays the big role for judgment. With flicker test on the sensitivity of the eyes, flicker value of umpires was measured before and after their work and the results were compared. The author has conducted the flicker test on many kinds of sports for grading the fatigue of each member. 2. In each experiment, with K.Y.S style flicker tester, the value of flicker fusion on the subject was measured ten or twenty minutes before the work as the control, and then was measured again within five minutes after the work. The critical fusion was measured on the subject while decreasing gradually the frequency of fusion from fifty cycle. 3. To summarise the result of this experiment, the grade of fatigue after umpires'work is different in each position-the more complicated, speedier and longer the job is, the intenser is the grade of fatigue. It is very important to make a adequate arrange-ment of work for good judgment of umpires, considering the skill, age, and physical fitness of themselves.
