Characteristics of torque production at the lower limb joints with special reference to type of muscle contraction / 体力科学

A study was conducted to investigate the relationship between the characteristics of torque production with special reference to eccentric and concentric muscle contraction and the structural and functional properties at the lower limb joints in the human kinetic chain. Ten male college athletes were tested with a isokinetic dynamometer (biodex) for eccentric and concentric torques during extension and flexion at the hip and knee, and plantar flexion and dorsiflexion at the ankle (angular velocity ; 30, 60, 120 deg/s) . The peak eccentric and concentric torques were higher in the order hip, knee and ankle joints, as the size of each muscle acting on its joint increased. However, the rate of peak concentric to eccentric torque (CON/ECC, %) was higher at the ankle joint than at the hip and knee joints. They tended to increase in the order of angular velocity ; 30, 60, 120 deg/s. These results suggest that the ankle joint is charactered by higher eccentric torque production. This characteristic is probably due to the fact that (1) the ankle joint is located at the end of the human kinetic chain and plays a role in transmitting the power to the ground effectively, (2) the muscle tendon complex acting at the ankle joint must have increased stiffness and tolerate great stretch loads to store and reuse the amount of elastic energy, (3) the hip and knee joints located at the center are the main sources of power supply. On the other hand, no significant correlations were observed among the torques at the hip, knee and ankle. These results suggest that torque production is independent at each of the lower limb joints, and is based on the structural and functional properties of each joint. These findings seem to be useful to clarifying the methods of strength and power training that can be adapted to the characteristics of torque production and the structural and functional properties of the hip, knee and ankle joints.

Effect of regular exercise on cold-induced vasodilation / 体力科学

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.<BR>Cold-induced vasodilation (CIVD) and maximal oxygen intake (VO<SUB>2</SUB>max) 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;<BR>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 VO<SUB>2</SUB>max increased markedly in the trained group, it remained almost unchanged in the control group. The degress of improvement in VO<SUB>2</SUB>max 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.<BR>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.<BR>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 VO<SUB>2</SUB>max 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.<BR>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.

Studies on comparison of physical measurements and blood properties of middle-aged and old farmers in Saga prefecture with reference to topographical features / 日本農村医学会雑誌

A survey of physical mesurements, blood pressure, blood mesurements and frequency of food consumption was conducted on 152 males and 229 females, aged 40 to 65 years, from three rural districts in Saga prefecture. The districts were Ariake (flatland area), Kohhoku (intermediate area) and Yamanouchi (mountainous area). While, on the aged -above 70 years, a questionnaire on daily living and health condioion was investigated.<BR>The results were summarized as follows:<BR>1) The values of skinfold thickness differed little among the districts. The rate of obesity by skinfold thickness both in male and female was lower than the result of National Dietary Survey in 1981. However, the average skinfold thickness in females were higher a little compared with the values of our suruey in same region in 1971.<BR>2) The prevalence rate of anemia in females was remarkably high (below 12g/dl of hemoglobin, 34%). It presumed that agricultural work load might heavy, and nutrients intake correspond to the work load was insufficient.<BR>3) From the results of frequency of food consumption, inhabitants in Ariake compared with Kohhoku more frequently intaked modern food e. g. meat, milk. On the other hand, Kohhoku was higher in blood pressure, HDL-cholesterol/total cholesterol ratio, and lower in triglyceride, total choresterol than Ariake. We guessed that the food consumption pattern mainly affect on the results of blood pressure and serum lipids.<BR>4) In relation to the correlation matrix which calculated on all districts, the higher the obesity, the higher the blood pressure, triglyceride, total cholesterol and cholinesterase activity, whereas the obesity decreased HDL-cholesterol and HDL-cholesterol/total cholesterol ratio.<BR>5) Among 90 persons aged above 70 years, the rate of ones who can not work from physically disability, and who have any desease was 18%, 51% respectively.

EFFECTS OF PHYSICAL TRAINING ON COLD-INDUCED VASODILATION OF FINGER / 体力科学

The following two aspects will be considered in this paper. First, in order to elucidate the effects of experimental increase of heat production on the cold-induced vasodilation (CIVD), we examined 20 males in CIVD before and after each exercise. Second, in terms of the difference in CIVD between trained and untrained individuals, 160 trained and 34 untrained males were examined. The results obtained from both of the experiments may be summarized as follows.<BR>1. The CIVD after one hour's outdoor exercise was enhanced in comparison with that before exercise. After exercise, the temperature before water immersion (TBI), mean skin temperature (MST) and temperature at first rise (TFR) during immersion were significantly higher, and the time to temperature rise (TTR) during immersion was significantly shorter.<BR>The amplitude of temperature (AT) was likewise significantly higher. These scores were calculated into resistance indices (RI) by Yoshimura's method and Nakamura's method (3 point method and 5 point method) . As a result, the RI by Yoshimura's method was significantly higher after exercise while that by Nakamura's method showed no difference. This suggests that a transient increase of heat content by physical exercise is ignored in the latter method.<BR>2. In regard to the features of CIVD in the trained as compared with the untrained, TBI, MST, TFR and AT were higher, and TTR was shorter and RI was significantly higher. There was a significant positive correlation between the years of experience of sports and RI.<BR>3. The CIVD was higher in those trained in outdoor sports than in indoor sports. The RI, classified by sport events was the highest in swimming followed in decreasing order by rowing, karate, baseball, track and field, judo, tennis, rugby, basketball, soccer, kendo, badminton, volleyball and table-tennis.<BR>This order was almost the same even after eliminating the effects of the years of experience of sports. Thus, it follows from this observation that the RI was higher in the trained in outdoor sports than in the trained in indoor sports. This result may be atrributed to the fact that outdoor sportsmen have more opportunities to be exposed to outdoor cold as compared with indoor sportsmen.

PHYSICAL LOAD DURING A LONG LASTING SPORTS TRAINING, EVALUATING MAINLY BY INDOCYANINE GREEN (ICG) TEST AS LIVER FUNCTION / 体力科学

The purpose of this study is to clarify influence of physical load on the liver function during an intensive athletic training camp, especially from the aspect of clearance ability of indocyaine green by the liver. The experimental subjects consisted of 12 male students in a track and field clubs, aged 16 to 20 years, who were subjected to a 7-day track and field training.<BR>Their physiological functions such as Flicker fusion frequency, Patellar refrex and Near point were measured every day during the training period, and ICG test and measurements of various blood components and serum enzymes were conducted early in the morning at the basal condition, on the firstday, the intermediate (4th day), and the final day (7th day) of the training period.<BR>The experimental results were obtaind as below.<BR>1. Judging from the variation of the physiological function and blood values, it was surely assumed that the physical stress was strongest on the intermediate day of training period.<BR>2. The activation of serum enzymes (GOT, GPT, LDH, CPK) showed a rapid rise on the intermediate day and then a slight decline toward the final day.<BR>3. Concerning ICG test, serum disapperrance rate of ICG (K) on the final day lowered significantly, comparing with that on the first day, while 15-minites retention rate (R5) rose significantly. The above results verified a delay of ICG clerance in the liver.<BR>4. Significant correlations were found between the changes of both R15 and K from the first to the final day and those of GOT, LDH and near point, respectively.<BR>5. ICG test conducted for the other three subjects on the intermediate day, on the final day and 2 weeks after the training period, revealed that K value on the intermediate day was lower than that on the final day and the value 2 weeks after was highest.<BR>This result suggests that the liver function was lowest on the intermediate day, corresponding to the changes of the physiological function mentioned in 1), of serum enzymes mentioned in 2), and behavior of leukocytes measured by Ishihara on the same subjects. The above results obtained by the present study suggest that the lowering of liver function participates closely in stress and fatigue due to the heavy athletic training.