The purpose of this study was to determine maximum oxygen intake and its relation to body weight of Japanese ordinary adolescents who consisted of 266 boys and 280 girls (12-18 years of age) living in Nagoya City.
The progressive treadmill exercise test was chosen as a work stimulus. Treadmill test was made with a constant slope of 8.6%. During the first 2 minutes, the treadmill was set in motion at a certain speed (160m/min for boys and 140m/min for girls), and then the speed was increased by lOm/min every succeeding minute until exhaustion. Expired air during running was collected in Douglas bag every 1 minute upto exhaustion. Then sampling gas was analyzed by means of a Beckman oxygen and carbon dioxide analyzer. The heart rate was calculated from ECG during running and the respiratory rate was determined with the aid of thermister attached to the inside of the mask. All experiments were performed in the afternoon (PM 3 : 00-5: 00) during the winter seasons from 1968 to 1970.
The results obtained in this study were as follows;
1) The mean value of maximum oxygen intake of the boys remarkably increased with age until 18 years of age. The maximum value was 2.81 l/mmn at 18 years of age. On the other hand, the mean value of the girls was almost constant over a wide range of ages from 12 to 18 except between 16 and 17. The maximum value was 1.941/min at 17 years of age.
2) The correlation coefficients and the regression equations were calculated between maximum oxygen intake and body weight.
Boys r=0.883 Y= 0.0457X+ 0.0902 ± 0.3094 (n; 260)
Girls r=0.595 Y=0.0149X+1.0648±0.2565 (n; 288)
Where Y is maximum oxygen intake in l/min and X is body weight in kg. The same correlation coefficients and regression equations were calculated relating to sex and age. As for boys, the coefficients of “X” in the regression equations increase with age from 0.0227 at 12 years of age to 0.0468 at 18 years of age. On the other hand, there was no distinct inclination in the regression equations of the girls.