The change in R-R interval (RRI) induced by rapid postural change from a squat posture to standing was analyzed in 8 healthy male students (20.3±1.2 years of age) before and immediately after maximal running exercise. We instructed subjects to stand up as quickly as possible, and to repeat the standing-up movement three times at intervals of 2 min. Heart rate responses and heart rate variability were analyzed by the change in RRI induced by standing up. Heart rate (HR) increased quickly at the onset of standing up. The time (T) until the maximal HR (Hmax) was reached 9.79±1.44 s after standing up, and then the HR after Hmax decreased rapidly with time. The maximal HR was 1.20 times higher while standing up than in the squat position. Maximal running exercise significantly delayed the time taken to reach Hmax after standing up, and significantly diminished the increased HR to 1.15 times. The Hmax/Hmin ratio, which expressed the magnitude of autonomic activity during standing up, was significantly lower following maximal exercise, indicating that the cardiac sympathetic nervous system seems to be in a state of hyperfunction immediately after maximal running exercise. These findings suggest that disturbance in the postural adjustment of the cardiovascular system immediately after intense exercise may be induced by the delayed response and decreased amplitude of the HR.

The purpose of this study is to conduct the examination of heart rate and speed variations with respect to the various interval trainings of swimming. One trained, one post-trained and one untrained swimmers were employed for this study. The experiment was conducted during the summer of 1968. The temperature of atomosphere varied from 30°C to 33°C and that of water from 27°C to 29°C.
The data of heart rate were obtained from the record of ECG. Two electrodes or ECG consisting of silver cups of 10mm in diameter were attached to the skin over sternum. In order to avoid mechanical and electrical disturbances, the electrodes were tightly fixed through the following procedures;
1) The electrodes were pasted on cleaned skin with ECG jelly.
2) The adhesive plaster was placed over the electrodes.
3) The adhesive plaster was coated with wax.
The wire of 20 meters was used to connect the electrodes and the recorder. On trial of interval training was consisted of two phases; 1) The active phaseTo swim 50 meters according to his swimming ability. 2) The rest phase.To take a 0, 5, 10, 20, 30, 45 or 60 seconds interval between each 50 meters swimming. Each trial of training was repeated ten times.
Results are as follows;
1) The longer the rest period is, the higher the swimming speed is.
2) All swimmers swim 50 meters at 60-80% of their maximum speed and the percent of the trained is higher than that of the untrained.
3) Maximum heart rates of the trained, the post-trained and the untrained during tenth swimming are 188, 180 and 173 respectively, which are the same in every trial.
4) Decreasing rates of heart rate during the rest period are 10 under in 5-10 seconds interval, 15-25 in 20-30 seconds interval and 20-50 in 45-60 seconds interval,

The present study was intended to determine max. Vo₂ and its relation to body weight of Japanese athletes. The subjects in this study were 151 male and female athletes who were Japanese excellent or good runners and swimmers.
Max. Vo₂2 was determined during the maximum running on the treadmill. 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 (180 or 200 m/min for male and 160 m/ min for female), and then the speed was increased by 10 m/min every succeeding minute until exhaustion. Expired air during running was collected in Douglas bag every 1 minute upto exhaustion. The sampling gas was analyzed by means of a Beckman oxygen and carbon dioxide analyzer.
The results obtained in this study were as follows ;
1) The regression equations were calculated between max. Vo₂ and body weight in relation to sex and sports (Table 1) .
2) Max. Vo₂ per body weight of the male swimmers ranges from 50 to 70 and that of the male runners is 70 ml/kg/min. For the female swimmers max. Vo₂ is between 40 and 60 and the female runners approximately 60 ml/kg/min.
3) The regression equation was calculated between the mean speed of 5000 m running as performance (Y) and max. Vo₂ per body weight as physical resources (X) for the runners.
Y=0. 0431X+2.50±0.232