Neuromuscular fatigability of different muscle groups was studied under various physiological conditions in eight healthy male subjects by means of EMG fatigue curve analysis (E/F ratio defined as the rate of rise in IEMG/force as a function of time) which has been commonly used. Under the experimental conditions and assumptions described in the present investigation, the following conclusions could be justified on the basis of the experimental results. 1. The E/F ratio for the biceps brachii muscle was significantly greater (p<0.0005) than that of the soleus muscle at 40% of MVC, suggesting that the biceps brachii with presumably greater %FT fibers were consistantly more fatigable than their own soleus muscle. 2. The exponential growth of the E/F ratio as a function of either the maximal sustaining time (Ts) or different fractions of MVC suggested a possible neurophysiological link between the fatigability of the biceps brachii muscle and their MU activities which might increase in an accelerated fashion. 3. The evaluation of static work capacity (Ws) described in the present study revealed that the differences in the critical force level and Ws during free circulation and arterial occlusion could be explained by the relative availability of muscle blood flow which might determine the rate of energy reconstitution. 4. The EMG data taken during a constant torque output on an electrically braked bicycle ergometer indicated that some shift in the MU recruitment and/or MU firing frequency may occur during the application of arterial occlusion causing local muscle hypoxia.
The present study was performed to investigate the effect of long distance walking upon physical functions for healthy male subjects. The first experiment was carried out in 1977, the second, in 1978, and the third, in 1979 in each autum season. At the first experiment, subjects began walking upon having breakfast, then ate and drank noting during first 30km, and took some foods during another 26km. Twelve hours and fifty minutes of time was spent for 56km walking including 15, 60, and 30 minutes rest periods in between. In the second experiment, subjects ate nothing after dinner of the previous evening and 35km walking took 6 hours during which some rest periods were taken for blood sampling. The third was 80km walking for two days. Subjects walked 40km in 8 hours in the first day and on the following day they walked 40km in ten hours and twenty minutes. They took foods and rest freely. From the view points of the changes in blood and urinary recordings obtained from those three experiments, the influences of long distance walking on the body indicate as follows ; 1) In case of long distance walking while nothing to eat and drink, the rate of serum saturated fatty acids composition decreased and unsaturated fatty acids increased. 2) In a fasting state, blood glucose gradually decreased, LDH activity increased and blood lactate, GOT and GPT activity presented no significant changes on long distance walking. 3) It was shown that the longer distance to walk, the lesser tendency in blood triglyceride even though subjects take a carbohydrate rich diet while walking. 4) In fasting state, less than 35km walking without foods, the stress to the body seemed not to be critical. 5) More than 40km walking in a day, even though taking meals, would result a significantly severe stress for body. 6) As long as usual meals are taken, 80km walking for two days continuously, 40km in each day, would not result in such a physical stress over the following days.
The effect of chronic exercise on heart weights, succinate dehydrogenase (SDH) activities, and norepinephrine (NE) concentrations was examined in the Wistar-Kyoto (WKY) and Spontaneously Hypertensive (SHR) rats. Nine week old animals were trained either by forced treadmill running (26.8 m/min-1 hr/day) or voluntary exercise in running wheels (@9, 000 m/day at peak) for 12 wks. Male rats subjected to forced treadmill running program gained weight significantly more slowly than sedentary freely eating controls (p<0.01) . Heart ventricles of exercised groups in WKY rats were heavier than those of the sedentary controls (p<0.05) . Ratio of heart ventricle weight to body weight of male SHR and WKY rats was significantly higher in the runners than in the sedentary controls (p<0.01) . SDH activities of the red gastrocnemius muscle were 30 and 100% greater (p<0.01) for the voluntary and forced exercise animals, respectively, than the sedentary controls. Changes in muscle enzyme activity and heart weight were used to verify that the forced exercise program had produced a trained state. Blood pressure (BP) of voluntarily exercised SHR was 10% less at 15 wks (p<0.05) and remained lower until the end of training than that of control SHR, whereas BP of forced-trained SHR was not lowered. There was no measurable change in BP of WKY rats as a results of training. The voluntary exercise program had no effect on the concentrations of NE in heart and adrenal glands of SHR and WKY rats. The NE concentrations of heart and adrenal gland in forced/trained SHR and WKY rats were @10-40% greater than those of sedentary controls. The results of these experiments indicate that chronic exercise can depress the blood pressure of SHR rats. However, difference between two types of exercise training suggests that the endurance capacity improved by chronic exercise may not be a primary factor to delay the onset of the hypertention.
To examine the personal space perception, measurements were conducted on both arms in 227 young men and women. Each subject, with his eyes closed, was instructed to stop the horizontal swing motion of his arm at the point he considered to be the middle of the range of possible motion on the horizontal plane, and this was repeated ten times. Mean values of bisected angles were deviated from the middle points in the direction of the horizontal adduction, although there were large differences between the individuals. The deviation was larger in the right arms than that in the left, and it increased with the increasing range of motion of the horizontal abduction. It was suggested that the gain of the personal space perception is higher in front of the body than in the side on the horizontal plane of the human shoulder.
Closing volume (CV) along with vital capacity (VC), expiratory reserve volume (ERV), and residual volume (RV) were determined on seven swimmers and seven physical education students in three positions (standing, supine, and prone) both in air and during head out water immersion. Lung volumes were also measured during bicycling and swimming to clarify if airway closure, as measured by CV, occurred during tidal ventilation in exercise. CV/VC and CC/TLC in standing position in air were significantly lower in our subjects than standard values obtained by Buist, A.S, and Leblance, P. This may suggest that the lung elastic recoil was increased by physical training. There was no difference among CV's measured in three positions, but CV increased when subject was immersed in water. Tidal volume (TV) in rest sitting position in air was in middle level of VC, and expanded evenly toward both expiratory and inspiratory sides with the increase of work load in bicycling. The level of tidal ventilation in rest supine position in air was lower than that in sitting position, and the increase in TV took place at the expense of IRV rather than ERV. FRC fell at rest in water, and the mean respiratory level shifted toward inspiratory side to increase ERV and FRC and to decrease IRV as the smimming speed increased. FRC and CC got close in supine bicycling, suggesting the increased probability of airway closure within the range of tidal ventilation level. CC was much less than FRC in other types of exercise.