I. Aim and Method
The cause of the stabbing pain in the side during exercise is not definitely known for the physiologist cannot be sure its appearance when he is prepared to study it. Therefore, in order to reveal the cause of this abdominal pain, the authors carried out first an investigation, then, on the basis of the result of the investigation, made attempt to induce the pain in the two series of experiments without any drug, balloon and so on.
In the investigation, the questionnares were distributed to the 200 young male athletes to know about their experience of the abdominal pain during exercise and about the relations between the pain and weather, physical condition, kind of exercise and eating-exercise time interval.
In the first series of experiments, eight healthy male students have not the history of an alimentary disorder were selected as the subject. Each subject came to the laboratory after fasting for eight and over hours, then they were loaded one of the two intensities of running on a treadmill in accordance with the procedure as showed in Tab. 1.
In the second series of experiments, six of the eight subjects of the first series of experiments were selected as the subject for they complained the pain during running which carried out immediately after drinking or eating. Each subject was loaded walking on a treadmill and cycling on a bicycle ergometer in accordance with the procedure as showed in Tab.2. And this cycling requires about the same oxygen cost as the running at 240meters per minute.
The test meal was consisted of baked egg (200g), fish ham (50g), raw cabbage (50g) and boild rice, and before the drinking or eating, each subject was advised to take water or boild rice as much as possible.
When the subject complained the pain during exercise, the exercise was stopped about one minute later.
II. Result and Conclusion.
The pain was found 24 cases during running and only one case during cycling. In 72% of these 25 cases, a great deal of abdominal gas and excreta was found, and in 42% of 31 cases which were not found the pain, a great deal of abdominal gas and excreta was also found. Most of regions of the pain were middle and lower abdomen (80%), and specially in the experiments carried out relatively short time after eating, most of regions of the pain were left side abdomen (86%) .
As for the time interval between the eating and exercise, the shorter the time interval, the higher rate of the pain was found.
In every case, the pain stopped within seven minutes after exercise and any effect on the body was not found.
From the result described above, it may conclude that the staple causes of the abdominal pain during exercise are (1) the abdominal gas or excreta is concentrated locally in the stomach or intestin by the movement of the body during exercise and distends the diaphragm or intestin, and (2) the stomach or intestin which is enlarged by the substances is rocked and tossed by the movement of the body during exercise and stimulates physically or chemically (local anaemia) to the mesentery or interior organs and so on.

Measurement of fatty mass (%Fat) by the method of Nagamine, maximal aerobic power (MAP) according to the method of Margaria et al., blood pressure and serum lipids were carried out on 104 males and 169 females aged 20-49 years to provide a basis for the evaluation of obesity by %Fat. Obesrvation of food intake was also done by a routine questioning and parsonal interview to clarify the characteristics of subjects. The energy from fats were about 25% of caloric intake and the animal fat were about 49% of total fats intake in both sexes. In the case of males, significant correlations were found between %Fat and HDL-choresterol (HDL), triglycerids (TG) and diastolic blood pressure (DBP) . Values of %Fat calculated from each regression equation when HDL=35mg/dl, TG=150mg/dl and DBP=89mmHg were about 21%, 20% and 33%, respectively. The highest value of %Fat was 27.4% in males. About 86.7, % of subjects whose %Fat above 20% showed one or more abnormal values (HDL below 34mg/dl, TG above 15lmg/dl or DBP above 90mmHg) . The appearance rate was about 61.3% in the case of subjects whose %Fat within the range of 15-19.9%. However, significantly lower rate of about 31.0% was found in the case of subjecte whose %Fat under 15%. From these results, it is considered that man whose %Fat above 20% is called obesity and man whose %Fat within the range of 15-19.9% is called mild obesity. The appearance rates of abnormal HDL, TG or DBP were about 15.4% in the case of Fit Non-obese group (MAP above 40ml/ kg/min & %Fat under 15%), about 42.9% in the case of Unfit Non-obese group (MAP under 40ml/kg/min & %Fat under 15%) and about 66.7% in the case of Unfit Obese group (MAP under 40ml/kg/min & %Fat above 15%) . Differences of the appearance rates between Fit Non-obese group and other two groups were significant but not significant between Unfit Non-obese group and Unfit Obese group. Though 11 subjects who were prohibited the exercise test by medical check and 9 Fit Obese subjects were not involved in this calculation of the appearance rate, it is said that combined method of %Fat and other functional measure such as MAP etc, is also necessary to evaluate the obesity. In the case of females, significant correlations were found between %Fat and HDL, total choresterol (TC) and DBP. However, values of %Fat calculated from each regression equation when HDL=40mg/dl, TC= 243mg/dl and DBP=89mmHg were about 72%, 208% and 57%, respectively. However, the highest value of %Fat was only 47.1% in females. Difference of the appearance rates of subjects who showed one or more abnormal values (HDL below 39mg/dl, TC above 244mg/dl or DBP above 90mmHg) were not found significantly even between the highest %Fat group (38.6±4.1%) and the lowest %Fat group (17.0± 2.1%) . Therefore, in the case of females, a cutoff point of obesity and non-obesity was not found. These results indicate that effects of the increase of body fat or physical inactivity on serum lipids and blood pressure are considerably moderate in females.

Measurements of heart rates during usual activities, maximal aerobic power and skinfold thickness were carried out as a basic research for the comparative study of the optimal load for successful living in modern society or in future ages. 18 urban sedentary male workers who came to work by car and were 19-38 years of age were selected as subjects.
The mean and S.D. of the maximal aerobic power was 35.8±5.2ml/kg/min, and those of 15 subjects (83%) were below 40ml/kg/min. The means of 12-hr heart rates during usual activities ranged within 71.5-95.0 beats/min. The mean and S.D. of the maximal heart rate during usual activities was 113±10 beats/min; 61±4% of their maximal heart rates during exhaustive exercises. Significant correlation was found between the maximal heart rate during usual activities and maximal aerobic power.

Measurement of maximal aerobic power (MAP), food intake and fatty mass (%Fat) were carried out on 104 males aged 20-49 years living in suburban, rural and moun-tainous districts as a basic research for determing successful living conditions in modern society or in future ages. Measurement of MAP was made indirectly follow-ing the method of Margaria et al. Each subject screened medically was given two different intensities of step up and down exercises, and MAP was calculated from heart rates immediately after exercises and the individual's estimated maximal heart rate. Observation of food intake was conducted by a routine qusetioning, however, checks and counterchecks were made by personal interview until reliable figures had satisfactrily been obtained. %Fat was estimated from skinfold thickness according to the method of Nagamine.
No age differences were found in MAP and 2oFat. Significant negative correlations were found between %Fat and caloric intake per kilogram of body weight per day (P<0.01) and between %Fat and MAP per kilogram of body weight per minute (P< 0.01) . A weak negative correlation was found between %Fat and caloric intake per kilogram of lean body mass per day. A significant positive correlation was found between MAP per kilogram of body weight per minute and caloric intake per kilogram of body weight per day (P<0.05) . Therefore, it is said clearly that physical inactivity rather than excessive caloric intake is associated with the development and mainte-nance of obesity.
Caloric intake and each nutrient intake of UO (Unfit Obese, MAP below 40m1/kg/ min & %Fat above 15%) group and UN (Unfit Non-obese, MAP below 40 ml/kg/min & %Fat below 15%) group were less than those of FN (Fit Non-obese, MAP above 40 ml/kg/min & %Fat below 150) group, respectively, and differences of those intakes between UO group and UN group were not significant. Mean calcium intake of UO group and UN group were less than the recommended allowance value of 10 mg/kg/ day. Both of MAP per kilogram of body weight per minute and per kilogram of lean body mass per minute of FN group were higher than those of UO group and UN group (P<0.01, respectively) . However, differences of mean MAP were not found significantly between UO group and UN group. It is considered that physical inac-tivity is not always associated with obesity, however, it is said from the health scien-tific point of view that fit non-obese man is more desirable than unfit non-obese one.

A compalative study of maximal aerobic power (MAP) with special reference to age were carried out as a basic study for determing the optimal physical load for successful living in modern society or in future ages. 169 males who have a sedentary living style profoundly affected by the motorization, 10-69 years of age, in suburban district of Fukuoka City (JAPAN) and 54 males who have a natural living style, 16-55 years of age, in rural districts of Nepal were selected as subjects. Measurement of MAP was made indirectly following to the method of Margaria et al.. Each subject were given two different intensity step up and down exercises, and MAP was calculated from heart rates immediately after exercises and individual's estimated maximal heart rate. % Fat was estimated from skinfold thickness according to the method of Nagamine.
Statistically significant correlations were found both of Japanese group (r= -0.554, P<0.001) and Nepalese group (r=0.561, P<0.001), and each regression equation etween MAP (ml/kg/min) and Age (yr) were as follows :
MAP=-0.350 Age +52.121 in the case of Japanese group.
MAP=-0.446 Age +63.395 in the case of Nepalese group.
However, difference of the regression coefficient was not significant.
Mean MAP per kilogram of body weight or per kilogram of lean body mass of every Japanese age groups wese lower than those of Nepalese groups with coincidental age, respectively. Generally, it is said that the socio-economical condition of Nepal today is a similar to that of Japan in the Meiji era. Therefore, it may be considered that modernization or urbanization have lowerd the system of Japanese people.
According to the review of literatures concerning to the living style and MAP in a evolutional and comparative point of view, it may be considerd that human races have maintained the relatively high MAP like Nepalese group today. Therefore, it is said conclusionally that the maintenance of mean MAP like Nepalese group is desirable in modern society or in future ages to prevent the degeneration of functions attributing the new health problem of modern society.

The relations between the power output during exercise and its maximal duration have been investigated on three young male subjects throughout the performance of heavy constant loaded cycling exercises with different intensities, all of which lead to exhaustion during the period from about 20 seconds to about 100 minutes.
The Aerobic Power output (mean total oxygen intake during exercise) develops rapidly with the increase of the maximal duration of exercise amounting to a few minutes in every case, and then, levels off approximately in one case, but declines steadily in the other cases.
The Anaerobic Power output (oxygen debt per endurance time of exercise) decreases rapidly with the increase of the maximal duration of exercise amounting to about 5 minutes, and then decreases slowly.
The relation between the Total Power output (sum of the Aerobic Power output plus the Anaerobic Power output) and its maximal duration is summarized as the two equations : log P = a - b logt, in the case of the t shorter than about 5 minutes, and log P =a′ - b′log t, in the case of the t longer than about 5 minutes. Here, P is the Total Power, tis the maximal duration, and a, b, a′ and b′ are constants. In each subject, the values of the constants a and b respectively. are greater than the a′ and b′
The present investigation was supported by a Grant in Aid for the Miscellaneous Scientific Research from the Ministry of Education.

“Power-Duration Curves” had been measured on three middle aged subjects through-out the performance of heavy constant loaded cycling exercise with different intensities. And the results were compared with the results of previous investigation on young subjects for the purpose to know the properties of the physical work capacity of middle aged man.
The relations between the Total Power output (TP) and its maximal duration (t) is summarized as the following two equations: log TP=a-b·log t, in the case of the t shorter than about 5-6 minutes, and log TP=a′-b′·log t, in the case of the t longer than about 5-6 minutes. The relations between the Anaerobic Power output (AnP) and its maximal duration (t) is also summarized as the two equations: log AnP=c-d·log t, in the case of the t shorter than about 1-4 minutes, and log AnP=c′-d′·log t, in the case of the t longer than about 1-4 minutes. The above equations are applicable to the results of every subjects in each age group, then, the age difference in quality is hardly found. However, the values of the constants a, a′, c and c′ in the above regression equations are respectively lower in the middle aged subjects, the other hand, the age difference is scarcely found in the values of the constants b, b′, d and d. It is also said that the endurance time of the certain Aerobic Power output of the middle aged subjects are shorter than young ones within the experimental region.
It is considered that the one of the reasons, both of the endurance times of the certain Aerobic Power output and Anaerobic Power output are shorter in the middle aged subjects than young ones, is the maximal aerobic power and the maximal anaerobic capacity of the middle aged subjects are lower than young ones.
In this paper, the Aerobic Power is a mean total oxygen intake during exercise, the Anaerobic Power is a oxygen debt per endurance time of exercise. The term of the “Anaerobic” is not most suitable one, however it is used for convenience. The Total Power is defined as the sum of the Aerobic Power plus the Anaerobic Power.