Muscle blood flows by means of hydrogen gas clearance method were measured on hindlimb muscles in sedentary control (nE) and exercised (Ex) spontaneously hypertensive rats (SHR) . SHR and Wistar control rats (WCR) were divided into two groups at 7 weeks of age ; SHRnE, SHREx and WCRnE, WCREx. Exercised rats were bred in cages with rotating wheels capable of running voluntarily for additional 10 weeks. Body weights of exercised groups in both SHR and WCR were lower than those of sedentary controls, whereas food consumptions of exercised rats tended to be more than those of sedentary controls. Ratios of the heart weight to the body weight of SHR and WCR were higher in exercised groups. There was no significant difference in systolic blood pressure obtained by an indirect tail-cuff method between exercised and sedentary control SHR. Resting blood flows in both M. Gastrocnemius and M. Soleus showed lower values in SHR groups than those in WCR groups. Postexercise blood flows at 1 Hz and 5 Hz were higher in exercised groups. These results suggest that peripheral adaptability of blood flow control to the exercise is still normal on hindlimb muscles in SHR.
To clarify length changes of human muscle, forearm girth was recorded during various handgrips by using the rubber-strain-gauge method. Subjects quickly lifted loads of 10, 20, 30% of the maximum grip strength (MVC) at a distance of 2 cm, and/or lifted and lowered those loads with the rhythm of 1 Hz. In isometric condition, handgrip was performed with muscle strength for several seconds in the same conditions as the above. Fatiguing successive contraction was performed with muscle strength of 30% MVC for a few minutes. 1) During ballistic contraction of forearm flexors, differences between the onsets of its discharge and the increase in forearm girth were about 20 ms in all conditions. The increase in forearm girth occurred prior to the onset of the rise in the loads, and its extent depended on the loads. 2) In repetitive handgrips, changes of forearm girth in the muscle contraction phase were similar to those of the ballistic contractions. In the muscle relaxation, recovery of forearm girth to its resting level was delayed with increase of the loads. 3) Forearm girth during successive contraction for a short time remained at an approximately steady level, while its extent depended on the muscle strength. During fatiguing successive contraction, forearm girth gradually increased with an increase in muscle discharge. These results suggest that length change in human muscle occures during muscle contraction in isometric conditions. Furthermore, this method is useful for the study of the human muscle shortening and lengthening, as to the muscle activity of concentric conditions and muscle relaxation process, even when there is no agreement of force-EMG relation.
Relaxation rate and contraction remainder of human forearm flexors following fatiguing repetitive handgrips were studied. These parameters were measured from the forearm girth and recorded by the use of a mercury-in-rubber gauge. Subjects performed handgrips: Subjects lifted and lowered the load of 30% of the maximum grip strength at a distance of 2 cm with rhythm of 1 Hz. 1) During the muscle relaxations, the decrease rate of forearm girth in the falling period and/or the lowering stage of the load increased with repetition of handgrips. 2) The forearm girth at the onset of handgrip progressively increased. 3) Even after the handgrips, the resting forearm girth continued to increase for a few minutes, and then progressively decreased. But it did not completely recover its resting level even after 1 hr. From these results, it is suggested that human muscles fatigued with repetitive contractions cause 'contraction remainder' in addition to the delay of muscle relaxation.
Daily physical activities for 12 severely physically and mentally handicapped persons were investigated using heart rates during a 24-hr period. The recorded heart rates were processed statistically and analyzed. The standard deviation and skewness for the severely handicapped persons with low ambulatory ability were significantly greater than those for the most severely handicapped persons without ambulatory ability. These properties confirmed that physical activities of daily living were extremely different for the two groups. The severely handicapped persons with low ambulatory ability had higher heart rates of about 10% relating to active physical activities. It was suggested that the active physical activities of daily living could contribute to the improvement of physical work capacity if these activities were more prolonged in duration. On the other hand, such higher heart rates were not observed in the case of most severely handicapped persons and extremely low function in their cardiorespiratory system was suspected. It became impor. tant to apply physical training to the most severely handicapped persons even though light work was performed passively.
The purpose of this study was undertaken to examine the effects of alcohol ingestion on temperature regulation during submaximal exercise. Five healthy male students participated in this study. Forty minutes of supine exercise using a bicycle ergometer was done following and without alcohol ingestion of 0.44 ml/kg. Respiratory gas exchange, rectal temperature, skin temperatures at 6 sites, finger blood flow, and heart rate were measured before and during the exercise. Respiratory gas exchange was measured by the Douglas bag method during 8-10, 1820, 28-30 min periods of exercise. Thermistor sensors were applied to measure rectal and skin temperatures, and finger blood flow was measured by venous occlusion plethysmography using a mercury rubber strain gauge. After low doses of alcohol, marked increase in finger blood flow and heart rate were observed in all subjects at rest. During exercise, VE, VO2, VCO2, and RQ were not different between the experiments with and without alcohol ingestion except only VE during the 8-10 min period. The rises in rectal temperature during exercise were the same between the two conditions. Heart rate was significantly higher after alcohol ingestion during the period of 20 to 40 min of exercise. Finger blood flow tended to be higher with alcohol ingestion, but not significant. It was suggested that low doses of alcohol (0.44 ml/kg) did not affect thermoregulatory or respiratory responses during submaximal exercise.
In this study, we investigated the effect of exercise training on serum and liver chblesterol levels and on biosynthesis of liver cholesterol in rats. The training was carried out at low [Low-Ex, 60% max O2 consumption (VO2) ] and high (High-Ex, 75% max VO2) intensities for 16 weeks. The energy expenditure was adjusted to be equivalent. The succinate dehydrogenase activities of gastrocnemius muscle in the Low-Ex group and High-Ex group were higher than that of control, 36% and 109% (p<0.05) respectively. The levels of total and high density lipoprotein cholesterol in serum were 14-26% lower than those of control, but no difference was detected between the trained groups. The activity of HMG-CoA reductase in liver microsome was significantly higher than that of control for both trained groups. However, the stimulation of this enzyme activity was not changed by training intensity.