The present study was designed to investigate the effects of low altitude training on swimming performance with setting the same duration (3-wk) and the same level of altitude (2, 300m) . Eight male (Gm₁) swimmers aged 13 to 19 years and four male (Gm₂) and eight female (Gf₂) swimmers aged 13 to 18 years sent to Mexico City, and they conducted swimming work outs. All of them were top Japanese swimmers of various events. They repeated the swimming training twice a day continuously for four days with one day rest. Hemoglobin concentration (Hb), red blood cell count (RBC) and hematocrit (Hct) were determined before, during and after the altitude training several times. The values of Hb, RBC and Hct of all three groups increased significantly from before training to after training except Hb in Gm₁. On the other hand, these three variables did not necessarily increase during the altitude training. Gm₁ and Gf₂ tended to increase Hb and RBC during the training. As for swimming performance at sea level, the individual best swimming records were improved significantly in 200m events, but not in 100m events in Gm₁. Therefore, it may be concluded that 3-wk altitude (2, 300m) training possibly improve swimming performance in the events equal to or longer than 200m at sea level.

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The purpose of this study was to compare two methods of CO₂ rebreathing-equilibrium method (Collier, 1965) and extrapolation method (Defares, 1958) -for determining the mixed venous CO₂ pressure (PvCO₂) during exercise. Following a sitting rest for 5 min, five healthy males performed upright bicycle ergometer exercises with work rate of 100 and 150W for 5 min. During both at rest and in exercise, PvCO₂ was measured twice to evaluate the reproducibility of both methods. The equilibrium method was performed according to that by Jones & Campbell (1982) . In the extrapolation method, instead of using the graphical analysis described by Klauaen (1965), PvCO₂ was directly calculated by applying the modified exponential equation (Defares, 1958) . In the duplicate tests, coefficient of variation was lower while correlation coefficient was higher, with increasing work rate in both methods. It was noted that these tendencies were more pronounced in the extrapolation method than in the equilibrium method. It was concluded that in contrast to the results of Auchincloss et al. (1980), the extrapolation method was more reproducible than the equilibrium method.

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Muscle activity of human ankle extensors during ballistic plantar flexion movement was studied by use of the rubber-strain-gauge method. The muscle power was measured by using the after-loading method. The subjects quickly extended the ankle joint with loads of 20, 40 and 60% of the maximum voluntary contraction (MVC) of ankle extensor muscles.
Maximum muscle power was exerted at about the load of 60% MVC. This result can presumably be attributed to the increase in the recruitment and firing frequency of motor units in gastrocnemius muscle with each load attached to ankle extensors.
Although the amount of muscle power increased consistently with an increase in the calf girth immediately after an onset of load lifting (r=0.8479, p<0.001), the period in which it obtained maximum velocity was not significant. On the other hand, muscle activity immediately after onsets of load lifing are important and girth changes in muscle should be considered as parameter for estimating the power output of human muscles during ballitic contraction.

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Triglyceride (TG) -fatty acid (FA) and phospholipid (PL) -FA profiles of skeletal muscles and brown adipose tissue (BAT) were examined in cold-acclimated rats (5°C, 4) (CA) and rats reared in cold for 25 generations (25 G) .
1. TG of skeletal muscles: Polyunsaturated FA (PU) and unsaturation index (UI) were higher in soleus than in red and white muscles of quadriceps. In white muscle of CA saturated FA (SA) decreased and PU increased. This was also the case in white muscle of 25 G. In soleus of 25 G MU and PU increased, and SA decreased.
2. PL of skeletal muscles: Higher SA, PU and lower MU were found in PL as compared with TG. In red muscle of CA SA increased while PU decreased. No significant changes were observed in white muscle and in soleus. In red muscle of 25 G a similar but more marked changes were found accompanied by lowered arachidonic acid and UI, thus suggesting decreased unsaturation of membrane lipid.
3. TG of BAT: In CA SA increased and MU decreased. In 25 G SA and PU decreased and MU increased.
4. PL of BAT: In CA SA, PU arachidonic acid, AI and UI increased, suggesting in-creased unsaturation of membrane lipid. In 25 G AI and arachidonic acid increased, but UI and PU were not changed.
These results indicate that cold acclimation would cause significant alterations of FA profiles in tissues which has been shown to be involved in heat production in cold. Their significance, however, should await further study.

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We determined the release of β-endorphin and prolactin into the blood, before and after 60-minute exercise of acute cycle ergometer in five healthy students and three athletes. This exercise induced an increase in circulating mean β-endorphin level [basal to after exercise level, 14.9±0.7 (mean±SE) pg/ml→57.1±17.0 pg/ml : p<0.05] and mean prolactin level [9.4±0.7 ng/ml→9.1±3.1 ng/ml : p<0.01] . There was a significant correlation between β-endorphin and prolactin values in all samples (r=0.892: p<0.01 : n=32) . Athletes tended to release greater amounts of β-endorphin and prolactin into the blood than students after acute exercise.
We find that acute exercise stimulates release of β-endorphin and prolactin in parallel and athletes have increased plasma β-endorphin and prolactin after acute exercise.

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This study was designed to compare post-exercise hyperemia between ramp and ballistic contractions in human triceps surae. Subject was asked to extend ankle joint in range of 20 degrees for 1 sec and with maximum effort against loads of 10, 20, 30 or 40% of maximum voluntary contraction (MVC) in ankle extensors. Amount of post-exercise hyperemia was calculated from changes in calf girth recorded by using two strands mercury-in-rubber gauge.
1) Calf girth after contractions transiently decreased below precontraction level and increased gradually until its peak value, over precontraction level, in about 8 sec. Calf girth recovered to resting level for about 30 sec.
2) After ramp contractions, amount of decrease of calf volume increased in order to loads of 10, 20, 30 and 40% MVC, but was not so after ballistic contractions. Amount of its increase, excess precontraction level, depended on loads in both conditions. These values were below 1.0ml/100 ml tissue.
3) Amount of decrease of calf volume after ramp contraction was larger than that of ballistic contraction, but amount of its increase was inverse.
4) There was significant coefficient between calf volume increase after contraction and maximum inflow rate (ml/min/100 ml tissue) calculated from the maximum gradient in rising phase of calf girth (r=0.5508, p<0.001) .
From these results, it is suggested that“milking action”in muscle generate with ramp contraction, and that disturbance of pulsatile inflow to muscle and chemical and neuronal regulations to generate post-exercise hyperemia pronouncely act by ballistic contraction.

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Six male and seven female children, aged five or six years, ran on the flat treadmill increasing running speeds every two minutes by 20 m/min till their subjective exhaustions. The first steps were started with the speeds of 80 or 100 m/min and the rest periods of 30 seconds were inserted between each successive step for the blood sampling. Expired airs for the determination of oxygen uptakes were collected during the last 30 seconds of every stage. Heart rates were recorded for each subject throughout the whole test session.
Two male and two female subjects were selected in order to determine their physical activity levels in the nursery school. Their heart rates were recorded from Monday to Saturday in a given week.
Analyses of physical activity patterns were tried by relating heart rate levels to circulorespiratory variables which were equivalent to 3 or 4 mmol/l blood lactate concentration (3m MLA or 4m MLA) .
By so doing, the following results were obtained:
1) Mean values of blood lactate concentrations observed immediately after the cessation of the last exhaustive steps were 5.16 m MLA for males and 4.70 m MLA for females.
2) Relative values of heart rate to 3 and 4 m MLA against maximal heart rate (% HRmax-3 m MLA and % HRmax-4 m MLA) were respectively 92.2% HRmax-3 m MLA and 97.5% HRmax-4m MLA for males and 94.9% HRmax-3 m MLA and 98.2% HRmax-4 m MLA for females.
The corresponding relative values of oxygen uptakes were 85.2% Vo₂max-3 m MLA and 94.3% Vo₂max-4 m MLA for males and 89.7% Vo₂max-3 m MLA and 96% Vo₂max-4 m MLA for females.
3) Mean values of heart rate recorded in the nursery through a given week except Sunday ranged from 89 to 114 beats/min for males and 106 to 126 beats/min for females. In the relative value of a heart rate against the heart rate equivalent to 4 m MLA, that is, HR 4 m MLA these values correspond to 44-57% HR 4 m MLA and 57-67% HR 4 m MLA respectively.
4) Accumulated duration time: Their hearts beat higher than 160 beats/min, except in the case of 800 m endurance run (only 0-4 and 0-6 minutes for males and 0-6 and 4-21 (touch of tachycardia) minutes for females) .
Percentages of accumulated duration time lower than 120 beats/min occupied 72-94% and 77-91% of 6 or 7-hour nursing time for males and 51-91% and 51-78% for females.
5) Absolute and relative values of mean heart rates in 800 m endurance run ranged from 183 beats/min (Net 83% HRmax, 90% HR 4 m MLA) to 199 beats/min (Net 98% HRmax, 104% HR 4 m MLA) for males and from 172 beats/min (Net 77% HRmax, 92% HR 4 m MLA) to 196 beats/min (Net 92% HRmax, 96% HR 4 m MLA), though the duration times were short.
6) Optimal intensity of work load was proposed to be the heart rate level of at least 190 beats/min for favourable development and/or improvement of the circulo-respiratory system in young children.

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Changes in myoproteins during development of rat skeletal muscle were investigated using two-dimensional gel electrophoresis. In M, soleus (SOL) which in adult, is composed predominantly of slow twitch fibers, fast type myosin light chains (fLC) were the major species and slow type light chains (sLC) were the minor species at birth. During development, the replacement rate of fLC to sLC sequentially occured so that LC patterns at 21 days postpartum were similar to adult where fLC were difficult to visualize. In contrast, M. extensor digitorum longus (EDL) always contained dominant fLC although sLC were found only for 5-9 days. LC 3 f became detectable at 5 days and gradually increased. In α-tropomyosin there were isozymes of fast and slow type based on difference in molecular weight, but not in β-tropo-myosin. Changes in isozymes of α-tropomyosin approximately corresponded with that in isozymes (fast and slow type) of LC in both EDL and SOL. During adult stage following birth, in EDL creatine kinase underwent a three-fold increase in molecular ratio to actin, whereas in SOL there was little change though increase took place transiently. These results suggest that with develoment many myoproteins change more dramatically in slow muscle than in fast muscle, and that transitions in LC isozymes and changes in distribution of histochemically typed muscle fibers may follow different time courses.

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Effects of treadmill running and restricted food intake on the metabolism of protein in several tissues were studied in male Wistar rats, aged 5 weeks and weighing about 100 g. Rats were divided into control group under free food intake (C), sedentary group under restricted food intake (Sr), exercise group under restricted food intake (Er), Food intake was restricted approximately to 66% of fed ad libitum for control group. Exercise program consisted of treadmill running for 60 minutes a day at 30 m/min on 6 days a week for 12 weeks.
A. The effects of sedentary under restricted food intake.
When compared with C
1) Lowering of body weight and increment in mg tissue/g body weight ratios. (M. Gastrocnemius, Liver, Brain, Testis, M. Soleus, M. Plantaris)
2) Significantly low level of protein content in gastrocnemius muscles, liver and kidney.
3) Inhibition in incorporation of ¹⁴C-amino acid mixture into brain and kidney protein in vivo.
B. The effects of exercise under restricted food intake.
i) compared with C
The effects were the same as those of Sr.
ii) compared with Sr
1) Lowering of body weight and increment in mg tissue/g body weight ratios. (Liver, Heart, Kidney, Testis)
2) Significantly low level of protein content in gastrocnemius muscles.
From this study it was suggested that, under the food restriction of long duration, the maintenance of protein content in brain in spite of the decrease of protein content in the other tissues indicated the existence of internal mechanism for life conservation in severe environment. And loaded with exercise under food restriction, protein content in gastra cnemius muscles decreased. Therefore, it was conceivable that skeletal muscles protein was consumed as energy for exercise.

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The higher average age of employees by the advancement of compulsory retirement age, and their sedentary life style in automated environments, has become an important issue in enterprise, because of the increase of adult disease and decreased physical fitness level.
The aim of this study was to evaluate the effects of a ten-year corporate health and fitness program to design for the purpose of assisting employees to stay well, through the results of health care examinations. The health and fitness program consist of health care examinations (medical checkup, physical fitness test and seminar for health promotion) and going through a physical training program on an individual basis.
With the increase of their average age, body weight and skin folds increased, but the prevalence of obesity (skin folds ; triceps+subscapula≥35 mm) showed no significant change. However, their blood pressure increased. In blood test, fasting plasma glucose and HDL-cholesterol levels were elevated significantly, but total cholesterol and triglyceride levels showed significantly decrease through this period. Physical fitness evaluation was markedly improved. Furthermore, the absence rate due to sickness was low for this period despite the increase of their average age.
The results suggest that long-term corporate health and fitness program is effective to improve employees' physical fitness level and possibly to prevent the progression of adult disease.

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