As physical elements appear to relate independently to the achievement in each running performance, it may be appropriate to separate the general population into several groups when physical traits specific to the achievement in each running performance are investigated. For this reason, the following four groups were arbitrary set: Group FF with higher running speed in both 100m and 10km runs, Group SS with slower running speed in both 100m and 10km runs, Group FS with higher running speed only in 100m run, and Group SF with higer running speed only 10km run. The purpose of this study was to compare physical elements and their developmental balance between 4 different groups in terms of running ability. The subjects were 166 high school boys aged 15 to 18 (X=16.9yr) . Within the limitation of the present study, the folowing conclusions were drawn:
1) Group SS was much inferior to the other groups in many tests representing power, agility, balance, coordination, and leg muscular endurance. This group also possessed higher body fat. And scores in such traits as power and agility were significantly higher in FF group than in SF group.
2) Factor analysis showed that physical fitness domain represented by 30 variables would be divided into six factors. While group SS possessed greater body bulk (F1) than the other groups, it had much inferior ability in power and agility (F5) . Cardio-respiratory function (F4) was significantly better in FF and SF groups as compared with SS and FS groups. However, no distinct differences existed beween groups in any of static strength (F2), body linearity (F3), and flexibility (F6) factors.
3) Finally, this study supports the hypothesis that the developmental balance of physical elements is specific to each running group. Particularly, it is interesting to note that group SS showed higher scres in body bulk and lower scores in cardio-respiratory function, power and agility as compared with scores in the other factors.