This study investigated the composition of change in the physical fitness of National Defense Academy of Japan male cadets as they progress through the school years. The subject data were the results of physical fitness measurements for cohorts of students who entered the Academy over four years, from 2004 to 2008. A third-order polynomial was applied to the physical fitness statistical values and the increases with progression through the school years were analyzed. The movement in the age-related change velocity curve derived from that analysis was also investigated. The results suggest that the physical fitness of male cadets can be expected to improve with the physical education program.