To investigate the time. the distance and the number of steps along different courses of `base-running`. J high School Baseball team was, made the object of this investigation and the conclusion reached is as follows: 1. The necessary time for running is 11"88 along A course. 11"86 along B curse. 12”04 along C course. and 11"84 along D course respectively D course turns out to require the min-mum of time. 2. They number of steps is 52.13 paces along A course 52.03 Paces along B course. 52.23 Paces along C course and 51.80 Paces along D course respectively 3. The distance is 84.01m along A course, 83.80m alone B course. 84.20m along C course and 84.80m along D course respectively. D course turns out to be the longest. 4. The angle of the change of direction from first Base to Second Base and from Second Base to third Base alike, is 50˚ along A. B and C course Along D course. the angle of the change of direction form first base to second base and from second base to third base is 55˚ but it has proved that the player can run fastest along this course. (Fig. 1 Refer to the angle of change of the direction along each course) Along D course, the runner can minimize, when be changes his direction. the centrifugal force caused by acceleration, and make the best of the acceleration. Therefor, D course is the most desirable.