One third to one fourth of main life is devoted to growth and motor development. An urbanization and a lack of big muscular activity in childhood may lead to impaire development of individual physical activity and attendant function.
A riding on a bicycle is the play which is so great favorite with the children. The purpose of this study was to determine the riding on the bicycle or cycling in children from view point of physiological aspect.
In this experiment, at first, using a special electric device maximum and ordinary cycling speeds were measured. Forty children, aged 5 years of old of male and female, were employed as subject. The maximum and ordinary cycling speeds were 3.40m/sec-4.45m/sec and 1.30m/sec-1.65m/sec for male, 2.94m/sec-3.68m/sec and 1.20m/sec-1.52m/sec for female, respectively. There was a difference in the cycling speed among the size and type of bicycle, sexuality, and physical fitness level of subject.
It is the further the purpose of this study to determine the oxygen intake and cardio response of the schoolboys and schoolgirls, aged 6-9 years old, during cycling with various speeds at different lanes. During cycling at flat lane heart rate and estimated oxygen intake were 113 beats/min-128 beats/min and 0.39 l/min-0.48l/min, respectively. It could be said that the physiological intensity of cycling is insufficient to improve the aerobic working capacity of children.
Making comparison of the oxygen intake and heart rate between the flat lane and upward slope, those for upward slope were much more than for the flat lane.

Information on daily physical activity is essential for determining daily nutritional demands and devising physical conditioning programs. In order to obtain reliable information on daily physical activity, it is necessary to record the activity in some way. Up to now, however, such data have been collected using retrospective questionnaires and observation, and by measurement of heart rate over extensive periods. These methods are too cumbersome and expensive.
The purpose of the present study was to develop a new device for recording physical activity in the form of an actogram. A pedometer was used to record the physical activity, and a microswitch was set inside the pedometer to convert the pedometer count into an electric signal, since it is advantageous to process the data by computer. The pedometer count was recorded in the IC memory of a computer with a 32-kbyte. The memorized pedometer count was fed into the personal computer through an interface, and after processing it was displayed as an actogram representing the activity pattern and the amount of physical activity.
The new device developed in this study could serve as a practical tool for recording the quantity and time course of physical activity during daily life, since it is small (110mm×70 mm×30 mm) and light (170g), less expensive and also convenient to handle.

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.