ABSTRACT
The gastrocnemius muscles are composed predominantly of type II B and II A fibers while the soleus muscle is composed of type I fibers. However, the relationships between the calcaneal bone stiffness and the triceps surae muscles consisting of the different types of skeletal muscle fibers are unknown. The purpose of this study was to investigate the relationships between the calcaneal bone stiffness and the gastrocnemius or soleus muscle thickness in 73 postmenopausal women. We measured the speed of sound (SOS) and the broad band ultrasound attenuation (BUA), using a ultrasonic measurement of the calcaneal and the gastrocnemius or soleus muscle thickness used to measure the B-mode ultrasound anatomy. There was a significant differences in age between the high-and low-SOS groups. In the high-BUA group, the body mass index, the lower leg girth and the triceps surae muscle thickness were significantly higher than those in the low-BUA group. This data indicated that SOS is related to ageing and BUA is related to the body mass or the muscle thickness. The other side, stiffness and SOS were significantly correlated with the gastrocnemius muscle thickness, but not with the soleus muscle mass. Therefore, this study suggests that the calcaneal bone stiffness is closely related to the muscle thickness, which may be related especialy to the fast twitch muscle.
ABSTRACT
The purpose of this study was to investigate the relationships between muscle mass or muscle power and bone mineral density in 43 postmenopausal women. Single photon absorptiometry was used to measure the bone mineral density and bone width of the calcaneuse. Isotonic muscle power of knee extensions (KE), knee flexions and incline squats (ISQ) were measured, using the power processor (VINE Co., Ltd.) . Statistical analysis demonstrated a significant positive correlation (p<0.05) between bone mineral density and lean body mass or muscle thickness. Although, bone mineral density was not significantly correlated with body mass index or fat mass, it was significantly corre-lated with leg muscle power. Further, the bone mineral density was also positively correlated with muscle contraction speed in the motion of KE (p<0.01) and ISQ (p<0.05), but not with muscle strength. This data suggest that the bone mineral density is closely related to the muscle power and/or speed rather than the muscle strength in postmenopausal women.
ABSTRACT
A study was conducted to investigate the cushioning effects of lower extremity functions on shock attenuation during landing on one leg.<BR>Optical methods were used to investigate the cushioning effects of lower extremity functions, since these facilitated the quantitation of kinematic variables such as angle, change in angle, position, displacement and velocity during the landing. The subjects were 5 healthy students ranging in age from 21 to 24 years. Ground reaction force (GRF) was measured with a force platform. The impact force peaks showed vertical force-time averages for 1 subject landing on one leg or two legs for 10 trials each from a height of 10cm.<BR>The peak/body weight of impact force of GRF upon landing was attenuated by the cushioning effects of the lower extremity functions, i. e. bending of the knee and ankle joints, more effectively on two legs than on one.<BR>Supination and pronation of the ankle joint influenced the impact force peaks, and the results of this experiment demonstrated significant difference between the number of discharge bursts of leg muscles upon landing on one leg and those landing on two, the former being higher.
ABSTRACT
Development of body equilibrium control in elementary school children was examined by analysing movement of the center of gravity (CG) during maintenance of an upright stance under various visual conditions. Eightyfour healthy subjects aged 7 to 12 years were instructed to stand in the Romberg position on a force plate for 30s with the eyes open, eyes closed, or eyers restricted to a 15-degree visual field. The length of trace, root mean square (RMS), and the power spectra of fore-aft CG movement were calculated by a personal computer.<BR>The results were as follows;<BR>1. The length of trace and RMS of CG increased in accordance with the decrease in the amount of visual information, and consequently increased in order: eyes closed, restricted visual field, eyes open.<BR>2. The length of trace and RMS of CG for boys decreased with increasing age, but none of these factors in girls was related to age.<BR>3. The power spectrum analysis of CG movement showed a peak of power at 0.4 to 0.7 Hz during both eyes closed and eyes restricted.<BR>4. This feature was shown in all age groups for girls, but only in the 11 to 12-year age group for boys.<BR>5. The greater the decrease in the length and the RMS of CG with increasing age, the higher the amplitude of the power spectrum peak.<BR>In conclusion, it was clarified that stability of posture in elementary school children is dependent upon the amount of visual information. The characteristics of the change in frequency zone manifested by decreasing the amount of visual information may reflect the developmental process of visual postural control in children.
ABSTRACT
The series of ECG examination were performed to study the influence of different kinds of exercise on heart of two untrained middle aged healthy male volunteers.<BR>One of them was assigned to run 10 kilometers or so, as fast as he could, once a day for 17 days. The other was assigned to run on a treadmill of three degree gradient for 20 minutes with a speed of 150 meters per minute once a day for 10 years. This volume of exercise was designed at a workload requiring 2/3 of his VO<SUB>2</SUB>max value.<BR>In the former case, frequent supraventricular premature beats with ventricular aberrant conduction occurred on the 21 st day from the beginning of the study. These changes on ECG were complicated with sinus arrhythmia and complete AV block on the 23 rd day. Sinus bradycardia and supraventricular bigeminy with ventricular aberrant conduction were noted on the 44 th day. Supraventricular bigeminies still persisted on the 213 th day, however they disappeared after that.<BR>The latter developed interpolated ventricular premature beats at rest for the first time in the 5 th year from the beginning of the study. These premature beats disappeared during exercise and recurred at rest. In the 8 th year ventricular premature beats became to show bigeminies.<BR>These results suggest that the severe exercise could cause various types of arrhythmia for a long period of time after the cessation of exercise even if the term of exercise would be short. On the other hand, the moderate load of exercise could not cause clinically significant arrhythmias inspite of continuous performance for a long term.
ABSTRACT
As well known, the adreno-sympathetic hormone - catecholamine - plays an important role in maintaining the stability of “milieu interieur”. Accordingly, a marked change may occur in catecholamine secretion in case of prolonged strenuous exercise such as marathon race where is required remarkable augmentation of cardiovascular functions. The authors had an opportunity of examining the physiological functions of all the participants in the First Tokyo International Women Marathon Race held on November 18, 1979, and collected urine samples from them before and after the race to evaluate the physiological load of the race in each woman participant by changes in urinary excretions of catecholamine metabolite (VMA) and some other substances.<BR>As for the subjects of examinations, 19 foreign runners were 31.1 years of age on the average (ranging from 20 to 48 years) and their average Rohrer's Index was 119.0, while 33 Japanese runners were 27.8 years of age on the average (ranging from 18 to 42 years) and their average Rohrer's Index was 125.8. The urine samples at rest were collected at 8 a.m. on the day before the race after more than 10 hours fasting, and the samples after running were collected in 30 minutes after finishing the race. Just after the collections, the authors made determinations of the urine volume and pH and qualitative tests for sugar, protein, occult blood, Keton bodies and bilirubin. Then the determinations of VMA were made by Pisano's method. The resulte obtained were compared among six groups classified by the performance, viz., the order of the arrival. The classification was made as follows : 1) 1-5, 2) 6-10, 3) 11-15, 4) 16-20, 5) 21-25 and 6) 26-46. The comparison was also made between the foreigners and the Japanese.<BR>Results:<BR>Although there could be no significant correlation between the performance and the age or physique, the Rohrer's Index was smallest in Group 1) and largest in Group 6) .<BR>The qualitative urine tests disclosed no marked change due to the running but protein less than 300 mg/dl was detected in the urine after running in 31 out of 40 runners. This fact seems to suggest that their physiological loads were considerably heavy. The urine volume on the average showed a decrease from 41.5 ml/hr at rest to 16.3 ml/hr after running, viz., 60.7 % decrement. The decrement was 53.2 % in the foreigners while it was 65.3 % in the Japanese. The urine volume was rather larger in Groups 5) and 6) than in the others. The urine pH on the average showed a decrease from 6.4 at rest to 5.6 after running, viz., 12.5 % decrement, and the decrement was 6.9 % in the foreigners while it was 14.9 % in the Japanese. Regarding the relation between the performance and the urine pH, there could be noted a tendency, the upper the ranking of the group, the smaller the change in pH.<BR>The urinary excretion of VMA on the average of all the runners showed a striking increase from 155.8 mg/hr at rest to 383.1 mg/hr after the running. The increase due to running was 121.4 % in the foreigners while it was 144.1 % in the Japanese. Regarding the relation between the performance and the VMA excretion, Group 1) showed no increase in the excretion on the average, while the other groups generally showed 100 % - 200 % increase in the excretion.<BR>On the basis of the above-mentioned findings, it was presumed that the physiological load of the marathon race was heavier in the Japanese runners than in the foreign runners, and in the lower ranking groups than in the upper ranking groups of the performance. In other words, the foreigners who showed excellent performance seemed to be highly adapted to the prolonged strenuous exercise by training and to have a regulatory mechanism of metabolism so efficient as to cope with heavy physiological load by small increase in catecholamine secretion.
ABSTRACT
A number of investigators have been concerned with the anthropometric as well as physical characteristics of sumo wrestlers during the past several decades. However, none have attempted to determine body density and percent body fat by the most accurate technique of hydrostatic or underwater weighings. Thus, a precise quantification of body density and percent body fat for the wrestlers has not yet been obtained. Ogawa et al. (1972) have predicted the body composition of sumo wrestlers from a formula which added the triceps and subscapular skinfold thicknesses. As the regression equation used in this instance was based on samples of normal young men, it may not have great predictive accuracy when used on the exceptional population of very stout athletes.<BR>The purposes of this study were : (1) to assess the validity of percent body fat estimation by skinfold thickness measurement when compared to the hydrostatic weighing criterion method ; (2) to determine the interrelationships between anthropometric variables for use in the clear assessment of the physical characteristics of ‘Shindeshi’ sumo wrestlers ; and (3) to thereby develop a formula that would reliably predict percent body fat using skinfold thicknesses and/or anthropometric measurements in this exceptional population. The interrelationships between anthropometric and body composition variables were investigated using 35 Shindeshi sumo wrestlers, aged 15-20 years (X=16.5±1.5) .<BR>The results of the present study can be summarized as follows.<BR>1. The Shindeshi in the present study possessed physiques more developed than those tested in the past, as evidenced by Rohrer's and Ponderal Indices which were approximately 180 and 26.2, respectively. The development of body weight was particularly notable (i.e., over 100kg) .<BR>2. Percent body fat for the Shindeshi was remarkably higher than that of a normal population of the same age, with approximately seventy percent of the Shindeshi possessing more than 20% body fat and less than 1.05000 body density.<BR>3. Body density and height correlated negatively and insignificantly with almost all the variables. In contrast, correlations of body weight, circumferences, and all other variables were, in most cases, high and positive, with body weight correlating least with height. The skinfold measurement correlating best with % body fat was that taken at the thigh site (r=0.898) . The circumference measurements correlating best with % body fat were obtained at the thigh (r=0.888 and 0.831) and the abdomen (r=0 885) parts.<BR>4. Of the six formulae for estimating % body fat, Sloan's correlated best with % body fat as determined by densitometry, and best approximated the mean value of 24.5%. However, all of the equations underestimated the measured % body fat of the Shindeshi.<BR>5. When an exceptional population is being investigated, estimation of % body fat should be done with a population specific equation to ensure predictive accuracy. The following multiple regression equation (r=0.963) should, therefore, be utilized for estimation of % body fat in sumo wrestlers.<BR>Y=0.2488x<SUB>1</SUB>+0.6172x<SUB>2</SUB>-14.3962 where x<SUB>1</SUB> and x<SUB>2</SUB> are abdomen circumference and skinfold thickness at thigh, respectively.
ABSTRACT
For the purpose of determining appropriate exercise prescription for middle and elderly men without exercise habit, when they begin daily exercise intending to improve their aerobic work capacity, the effects of 10 minute walking on a horizontal treadmill at the speeds of 80m/min, 100m/min and 120m/min on the respiro-circulatory functions and blood ingredients and so on were compared. Four healthy men aged 44-72 served as the subjects. They showed no particular abnormality in medical check and various tests at rest.<BR>Treadmill walking, of course, augmented oxygen intake, pulmonary ventilation and tidal volume according to the walking speed, and the augmentation was especially marked in case of 120m/min. The heart rate continued to increase during walking in case of 120m/min. The index (heart rate×pulse pressure) adopted as a relative indication of cardiac output presented no marked difference between 80m/min and 100m/min, but the value in case of 120m/min was about twice as much as those in cases of 80m/min and 100m/min. Moreover, the oxygen removal was appreciably lower in case of 120m/min than those in cases of 80m/min and 100m/min. Changes in blood contents of several substances were also marked in case of 120m/min, and the increase of lactate was especially striking. Urine tests revealed general tendencies of decrease in urine volume, decline of pH, and slight increase in excretion VMA, 17OHCS and 17KS.<BR>The above-mentioned findings seem to suggest that 10 minute walking at the speed of 100m/min is to be most preferable in case of exercise prescription for healthy middle and elderly aged men in order to improve their aerobic work capacity, because walking at that speed causes sufficient and appropriate augmentation of metabolism and activities of respiro-circulatory functions.<BR>Additional remarks: the present study was carried out on the basis of the experiences of 20 minute jogging corresponding to 2/3 VO<SUB>2</SUB> max made by middle aged men 5 days a week for 5-6 years.