The present study was carried out to investigate differences in hormonal and metabolic responses to moderate exercise in the post-absorptive state and during a 33-hour fast. Secretory factors and the roles of regulatory hormones of carbohydrate and lipid metabolism during moderate exercise were assessed baesed on these data. Energy substrates in the blood (glucose, BG; lactate, LA; triglyceride, TG; free fatty acids, FFA; free glycerol, FG) and plasma hormones (ACTH; GH; Cortisol, Corti; glucagon, IRG; insulin, IRI) concentrations were measured from 12 h to 33 h during the fasting period (12: 00, 24: 00, 06: 00, 09: 00), and 3min, 10 min and 30min after moderate treadmill exercise (estimated 70-80% of VO₂max) for 20 min under fasting conditions between 09: 00 and 11: 00. These results (in the fasting experiment, Fast) were compared to the results on a normal diet (N-D) .
The results were as follows:
1. No differences in mean VO₂ and respiratory exchange ratio (RER) during exercise were observed between the Fast and N-D experiments. Mean heart rate during exercise in Fast was higher by 3.3±2.2 bpm (p<0.05) .
2. Serum FFA and FG concentrations were significantly higher as a results of 24-hour fasting than the values measured at the same time in N-D. No significant change in serum TG concentrations were observed in Fast. While BG and LA concentrations remained low, and in small changes occurred in then both during Fast.
3. Slightly higher levels of plasma ACTH, GH and IRG were found in Fast, but they were not significantly different from N-D. Plasma Corti concentrations gradually increased after 24 hours of fasting, and were 1.9 times higher at 09: 00 after 33 hours of fasting than on N-D. Plasma IRI levels, however, remained low, and the molecular ratio of IRG to IRI (IRG/IRI) was higher throughout Fast (1.8 to 10.6 times higher than on N-D ) .
4. Plasma ACTH, GH and Corti concentrations increased markedly after exercise, and remained high until 30 min on Fast. No significant change in IRG and depression of insulin secretion were demonstrated after exercise on both treatment.
5. Significant correlation between changes in plasma ACTH and Corti concentrations were observed throughout the experiments (Fast, r=0.562; N-D, r=0.528) .
6. All of the energy substrates except blood TG increased after exercise, and the net increases in LA and FG (Δ) on Fast were significantly higher than on N-D. Significant correlations between the changes in the concentrations of FFA and FG (Fast, r=0.745; N-D, r= 0, 696), LA and BG (Fast, r=0.689; N-D, r=0.623), and FFA and LA (Fast, r=0.579; N-D, r= 0.479) were detected throughout both experiments.
7. The coefficients of correlation between changes in plasma ACTH and FFA, and between BG and LA concentrations were higher on Fast than N-D. However, changes in plasma IRI and IRG concentrations were not directly correlated with any other changes in energy substrates in the blood in either treatment.
The results indicated that moderate exercise for 20 min after a 33-hour fast causes marked responses in ACTH, Corti and GH secretions. It appeared that Corti secretion de-pended on ACTH, and that Corti facilitated fatty metabolism during exercise on Fast. However, secretion factors and the role of GH during exercise remain a matter of conjecture.

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The nutritional status and exercise training programs were compared between adolescent Japanese and Chinese athletes who belonged to the top schools for track and field and basketball in their respective countries. The mean energy intake was about two times greater in Chinese athletes than in their Japanese counterparts. Chinese athletes consumed 1.5-2.0 times more carbohydrate, 1.9-2.3 times more protein, 3.5-7.5 times more calcium, 2.9-3.7 times more iron, 1.72-2.2 times more vitamin B1 and 1.3-1.8 times more vitamin B₂. Almost all the Chinese athletes consumed more than the Recommended Dietary Allowance standards for energy, protein, calcium, iron and vitamins A, B₁, B₂ and C, while many Japanese athletes did not meet them except for vitamin A and C. The Japanese athletes had more inadequate training schedules, insufficient weight training, and unsatisfactory amount and intervals of rest. These results indicate that Japanese athletes have certain deficiencies in their comprehensive training programs in consideration to nutrition, exercise and rest.

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Circadian rhythms (diurnal variations) in many physiological parameters have been reported. However, there are no data on gas exchange kinetics at the onset of exercise. The purpose of this study was to establish whether there are circadian rhythms in gas exchange kinetics at the onset of exercise.
Six male subjects performed 120W exercise on a cycle ergometer for 7 min in the morning (AM; 7: 30-8: 30) and evening (PM; 16: 30-17: 30) . Rectal temperature (Tr) and mean skin temperature (T_sk) at rest were significantly higher PM than AM, the differences being 0.9±0.2°C and 0.7±0.2°C, respectively. Respiratory and circulatory parameters at rest and during exercise were not different between AM and PM. The time constants of oxygen uptake (Vo₂), carbon dioxide output (Vco₂), minute ventilation (V_E), heart rate (HR), and oxygen pulse (Vo₂/HR) showed the same results. There was no relationship between temperature parameters (Tr, T_sk) and the time constants.
It is suggested that circadian rhythms reflected by the change in body temperature do not have any effect on gas exchange kinetics at the onset of moderate bicycle exercise.

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A study was conducted to determine the minimum quantity of leg exercise required to prevent disuse atrophy of the quadriceps femoris muscle during bed rest. The subjects were 10 normal young university students with a mean age of 21.1 years. First, analysis of rectified filtered electromyography (RFEMG) was performed on the rectus femoris and vastus medialis during walking with cadences of 100 steps/min and 150 steps/min. Then, the effects of straight leg raising (SLR), patella setting (PS), knee extension-flexion in a supine position (KEF) and knee extension in a sitting position (KE) were analysed for each muscle using the same method. Based on the value of RFEMG for each muscle during walking, the repetition number for each exercise was calculated. For the rectus femoris, the repetition number for each exercise corresponding to 10000 steps with a cadence of 100 steps/min was 289 for SLR, 466 for PS, 1255 for LEF and 1663 for KE. For the vastus medialis, the corresponding numbers were 1223, 381, 6367 and 2170, respectively. When the cadence increased to 150 steps/min, the repetition number of each exercise for each muscle also increased. These results indicate that high repetition exercise is recommendable to prevent disuse atrophy of the quadriceps femoris muscle. Therefore, the activity of patients should be increased to stimulate weakened muscles such as the quadriceps femoris during hospitalization.

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A study was conducted to examine the recovery of vagal activity after strenuous exercise based on changes in the magnitude of respiratory cardiac cycle variability, changes in the phase of this variability and the mechanism of the change. Six healthy male university students were studied for 5 h after exhaustive treadmill running. For cardiac cycle (RR) and blood pressure, the magnitude of respiratory variability and phase difference between respira-tory variability and respiration were measured. Respiratory period and tidal volume were maintained at 6 s and 21, respectively.
1. The amplitude of respiratory RR variability decreased markedly after exercise and returned almost to normal after 2 h of recrvery. The phase of RR delayed with exercise, proceeded rapidly 2 h after exercise and progressively after that.
2. The amplitude and phase of respiratory systolic blood pressure variability were almost stable before and after exercise.
Based on these results, we conclude that vagal activity inhibited by strenuous exercise recovers about 2 h after the end of exercise. The delay in the phase of respiratory cardiac cycle variability with exercise may reflect inhibition of vagal activity.

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Healthy male subjects were asked to hold their breath in air at the tidal inspiratory level, and time-dependent changes in mean values of several parameters of cardiovascular function were studied. The heart rate increased abruptly after the beginning of breath-holding and then decreased slightly with time. The stroke volume (SV) remained significantly low until the end of breath-holding, so that the cardiac output was decreased in parallel. With regard to the systolic time interval, the totai eiectromechanical systole and the left-ventricular systolic time (LVET) were not significantly changed, whereas the pre-ejection period (PEP) was markedly prolonged. Therefore, ratios of PEP/LVET and SV/LVET were increased and decreased with time, respectively. As the systolic, and in particular the diastolic blood pressures were elevated, the pulse pressure was reduced. Ratios of the diastolic and systolic times in relation to the heart rate at rest, during breath-holding and during recovery after breath-holding were all proved to be described by a single regression curve. However, the ratios obtained for cycling exercise at various heart rates showed a marked shift above the curve. These results clearly indicate that cardiac performance is lowered during breath-holding in air.

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Using three-dimensional (3 D) imaging, we investigated the morphological characteristics of the M, latissiums dorsi (LD) and M, erector spinae (ES) of the dorsal trunk in judo athletes employing a computer graphics system on magnetic resonance imaging (MRI) . The subjects were five healthy untrained women (HUW) without lower back pain syndrome, and five Japanese female elite judo athletes (EJA) . There was no significant difference in height or weight between the HUW and EJA. Three-dimensional imaging of the LD and ES was reconstructed visually, based on MRI consecutive slice data taken from the first thoracic vertebra to the symphysis pubis along the trunk. Then the volume of the LD and ES was determined using a surface reconstruction algorithm.
The morphological characteristics of the LD in the EJA appeared to indicate enlargment compared with those in the HUW, whereas the characteristics of the ES in both groups were similar. The volume of the LD was significantly different between the HUW (226.6±33.18 ml) and EJA (438.1±107.8 ml), whereas that of the ES showed no difference (HUW; 257.4±78.8 ml, EJA ; 284.0±74.82 ml) . In the EJA, but not in the HUW, there was a significant positive correlation between the volume of the LD and weight, and differences were noted between the two regression slopes. There was also a positive correlation between the volume of the ES and weight in both the HUW and EJA, which showed the same simple linear regression slope. These results suggest that the muscle hypertrophy evident in the LD, but not in the ES, is related to the effects of Judo training.

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Eighteen male college students who exercised regularly (the trained group) and 20 students who did not participate in regular exercise activities (the control group) were evaluated.
Cold-induced vasodilation (CIVD) and maximal oxygen intake (VO₂max) for each student were measured in May for four consecutive years. In addition, the motor capacity test devised by the Ministry of Education was given to each student. CIVD and values of motor capacity obtained from the students are summarized as follows;
A. The motor capacity test consists of five items (motor skills) . There was no significant difference in muscle strength between the trained group and the control group. The degrees of improvement in explosive power and endurance capacity over the three years were greater in the trained group. It was significant that the degree of improvement in the total scores for the motor capacity test over the three years was 21% in the trained group in contrast to only 8% in the control group. While VO₂max increased markedly in the trained group, it remained almost unchanged in the control group. The degress of improvement in VO₂max over the three years were 25% in the trained group and 8% in the control group. The values in the control group were almost the same as the physical fitness standards, but those of the trained group were higher than the standards.
B. Mean skin temperature and temperature at first rise in the trained group were higher throughout the three years than those in the control group. The time of temperature rise became shortened over three years in the trained group, but in contrast became rather longer in the control group. The range of variations in the amplitude of temperature was 9°C-13°C in the trained group and around 10°C in the control group. Resistance index (RI) of the trained group was higher in the first year; by the time the students became seniors, there was a 43% increase in RI. In contrast, RI in the control group was almost unchanged. The degree of improvement over the three years was 10% in the latter group.
C. The correlation coefficient of RI with scores from the motor capacity test was 0.499 in the trained group and 0.270 in the control group. The correlation coefficient for all the subjects was 0.605. The correlation coefficient of RI with VO₂max was 0.500 in the trained group, 0.160 in the control group and 0.623 in all the subjects. These values indicate that CIVD values and improvement in motor capacity are closely related, and that the interdependence of these two parameters is particularly strong in trained individuals.
These results indicate that the degree of CIVD is determined not only by genetic factors and chronic exposure to cold temperatures but also by physical training.

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