The purpose of this study was to determine the interrelati6nships among recordings in nine different running performances varying in distance from 50 m to 10 km, and the contribution of physique and physical fitness elements to each running performance. A total of 43 test items representing running ability (9 items), physique (7 items), and physical fitness (20 items) was examined on 167 healthy young boys aged 15 to 18 years. The major findings are summarized as follows: 1) The average running speed declined remarkably from 7.0 m/s in l00 m running to 3.7 m/s in 12 min running (x=2639 m) as the running distance increased, whereas the mean speed in distance running longer than 12 min running was almost constant. The mean speed in 12 min, 5 km, and l0 km running was approximately 50% of the mean speed of 50 m running. 2) The correlation coefficients of 50m running performance decreased remarkably from r=0.84with l00 m running performance to r=0.37 with 12 min running performance as the running distance increased. In contrast, the correlation coefficients of 10km running performance ranged from r=0.40with l00 m to r=0.90 with 12 min. 3) The contribution of physique to running performances seemed to be somewhat greater in distances shorter than 400m than in distances longer than 600 yards. Particularly, the contribution of body bulk to running performances was relatively large.. 4) The overall contribution of physical fitness elements to running performances in shorter distances (≦600 yeards) was relatively greater as compared with those in longer distances (≧800m). 5) The contribution of power to running performances decreased progressively up to 600 yards, while that of muscular endurance was almost constant throughout the range of distance. However, the relative contribution of muscular endurance among physical fitness elements seemed to increase progressively as the distance became longer. 6) Static strength and flexibility showed rather low relationships with running performance in distances shorter than 600 yards. Cardiorespiratory element related significantly with running performances longer than 400m, and the contribution of this element was relatively greater to running performances in longer distances (≧1500 m) than to those in shorter distances (≦800 m). 7) Agility, balance, and coordination were also found to contribute significantly to each running performance. However, the contribution of agility to each running performance seemed to decrease progressively up to 800m as the distance became longer.