ABSTRACT
The effect of endurance training on aerobic power and the relationship between aerobic power and running performance were investigated longi tudinally on eleven junior runners for 5-7 years, starting from the age of 14, 15 yr. Maximal aerobic power was measured with the subject running on a motor-driven treadmill. The subjects were divided into two groups (Group I, II) .<BR>The results were as follows ;<BR>1) Group I (superior junior runners) showed greater aerobic power and better running performance compared to Group II (good junior runners) . The values for Group II were between those for Group I and for ordinary school boys.<BR>2) Aerobic power for Group I increased from 14, 15 to 18, 19 years old, while aerobic power for Group II decreased to the similar values of the ordinary school boys after stopping the running training.<BR>3) Greatest value for aerobic power was obtained on Subject A as follows : 3.63 1/min (61.5 ml/kg. min) at 14.7 yr of age, 4.67 1/min (74.6 ml/kg. min) at 17.8 yr, 5.04 1/min (76.3 ml/kg. min) at 20.7 yr.<BR>4) Improvement in running performance was closely related to the increase in aerobic power (1/min) for the junior runners during the age of 14 to 18 yr.