ABSTRACT
Keeping upright stance is important to other complex motions like locomotion and running for human beings. The mechanism of balance-keeping control in upright standing is still unknown. This study was conducted to analyze the body sway by using a simple PID (proportional, integral, derivative) control model and to investigate the influence of vision on its gains. Ten healthy subjects took part in the study. The upright body was modeled as one-link inversed pendulum model. While determining the model parameters according to subject's physical statue, the gain of PID parameters, (<i>K<sub>P</sub></i>, <i>K<sub>D</sub></i>, <i>K<sub>I</sub></i> are gains of proportion, derivative, and integral respectively.) could be estimated. Four kinds of visual patterns, (three for central visual field stimulation, one is eyes closed) were designed for visual stimulation. The results showed that the gain of <i>K<sub>D</sub></i> was decreased significantly in eyes closed (131.5±37.6 Nms/rad in eyes open and 90.4±26.0 Nms/rad in eyes closed, p<0.001), and, <i>K<sub>P</sub></i>, <i>K<sub>I</sub></i> were not changed. The results suggested that the PID control model was a promising means for individual balance ability analysis and that the visual effect on balance-keeping control in upright standing was analogized to a damper in the mechanical system.
ABSTRACT
The purpose of this study was to identify the relationships between trunk sway (TS) and the motion of center of pressure (COP) during quiet upright stance. Eight young healthy subjects (averaged 24±6.7 years) including 3 females were recruited for this study. By comparing TS with COP, we found that TS is moving in phase with COP both in lateral and sagittal plane. On the basis of observations that the COP-TS error signal is very similar to the changes of friction between the feet and floor. We also found that the friction is the impetus of trunk sway obeying the Newton's law. Then, a dynamic model between TS and COP can be identified. The results showed that TS and the motion of COP are in accordance with a specific differential equation. Supporting TS is <I>v</I> and COPS is <I>u</I>, then <I>u</I> can be expressed as : <I>u=-Hm/k v+hv</I>, where <I>H, k, h</I> are constants, <I>m</I> is the body mass. The simulation results fitted the experimental findings very well. The results suggested that TS instead of COP is a promising index for human standing ability assessment.
ABSTRACT
Physiological characteristics of middle-aged and old runners, who competed in the international 10km or 25 km race, were investigated. All of 2260 runners were aged 40 to 86 years. They have been trained for at least one years. Body composition, resting blood pressure, blood composition, serum metabolites, serum enzymes and pulmonary function were measured. The runners who competed in 10 km race were compared with those competed in 25 km race. Relation between running performance and physioloigical parameters were discussed.<BR>1) Average running speed was faster in 25 km group than in 10 km group, although 25 km group ran a longer distance. In daily training, 25 km group also showed longer running distance than in 10 km group.<BR>2) Body weight averaged 55.9±6.82 kg in a whole group of 2260 runners. Skinfold thickness averaged 6.1±2.50 mm in triceps, and 10.9±3.78 mm in subscuplar. These values were remarkably lower than normal values of corresponding age of the Japanese. 25 km group showed significantly lower values in these parameters than 10 km group. The runner who made better performance also showed lower values in these parameters.<BR>3) Resting blood pressure of the runners averaged 144.3±17.0 mmHg in systole, and 86.2±11.0 mmHg in diastole. No difference were found between 10 km group and 25 km group in blood pressure.<BR>4) RBC, Ht, Hb of 645 runners averaged 411.8±37.4×10<SUP>4</SUP>/mm<SUP>3</SUP>, 40.3±3.70%, 14.5 ±1.25g/dl, respectively. These values were lower than in normals. Among age group of 40-49yrs, negative correlation between running speed and these heamatological parameters were found. Better runner showed lower values in these parameters.<BR>5) Blood glucose, serum choresterol, LDH and CPK were not different from normal values.<BR>6) Pulmonary function were not different from normal values. Remarkable decrease with increasing age were found in pulmonary function.
ABSTRACT
Preliminary studies on the blood composition were carried out with 40- to 82-year-old runners when they were at rest. 790 male subjects who had kept the routine training of running over a year were examined. And the results were compared those with the corresponding control groups who had no particular routine training.<BR>The results were as follows:<BR>1. Runners' values for Red blood cell count and Hematocrit were decreased with age.<BR>2. Runners' values for Red blood cell count, Hemoglobin and Hematocrit were approximately 10%, 9% and 4% lower than those of the corresponding control groups of almost all age groups. On the other hand runners' values for MCH (Mean Corpuscular Hemoglobin) were approximately 8% higher than the control group values for all age groups.<BR>3. Runners' values for reticulocyte count and osmotic fragility of the blood were within normal range.<BR>4. Comparison between runners of 10 km group and 25 km group of blood composition was made; the age group of forties of 25 km group of both Red blood cell count and Hematocrit were significantly lower than the corresponding 10 km group.<BR>5. Dailly training programs of 25 km runners were significantly longer than those of 10 km runners for all age groups.
ABSTRACT
The purpose of this study was to investigate the changes of blood components of middle and old aged runners in marathon running. The results were as follows.<BR>1) Mean running time of marathon was 250 min. Some of subjects did last spurt.<BR>2) Change of body weight was -4.8%. RBC, Hct, and Hb were changed by -4.8%, -4.4%, and -4.7% respectively. The decrease of plasma volume was 7.8% according to Dill's method.<BR>3) Blood glucose was 112 mg/dl at rest and decreased to 70 mg/dl after running. The glucose level of five subjects was in range from 59 to 50 mg/dl.<BR>4) The increase of L.A. was 52%. The L.A. after running tended to correlate to the running speed at last spurt.<BR>5) T.G. significantly decreased after running. On the contrast, FFA increased by 323%. This increment of FFA correlated to mean running speed (r=0.681, P<0.05) .<BR>6) The increments of GOT, GPT, and LDH were 71%, 62%, and 61% respectively, The decreases of LDH-1, 2 and increases of LDH-4, 5 were found after running. Furthermore, AGOT and 4GPT correlated to the running speed at last spurt or L.A. after running.
ABSTRACT
In order to elucidate the changes of cardiovascular functions on the long distance running in middle-aged and old men (aged 40-87 years) performing the running training at least over a year measured on blood pressure and ECG before and after the 10km, 25km and 42km running, respectively. Furthermore, several runners fainted during and at the end of running were also measured on the blood pressure at the fainting. The results were summarized as follows, <BR>In the 10km, 25km and 42km running the average values of systolic (excepting the 10km), and diastolic pressure after running were significantly lower than those average values before running. Further, it was noted that the higher the systolic and diastolic pressure before running were the more the reduction of those blood pressure after running in any distance, and also with the prolongation of running distance the reduction of those blood pressure became more remarkable. Especially, the reduction of blood pressure in the fainted runners was very remarkable. On the other hand, the pulse pressure showed no significant difference between before and after running.<BR>On the observation of ECG recorded before and after running, the shortening of PQ interval and the prolongation of QTc were noted after running, especially the prolongation of QTc in a group of 42km was remarkable. While the reduction of T<SUB>II</SUB> voltage was also found after running.<BR>It may be therefore thought that a long distance running in middle-aged and old men bring on large changes for their cardiovascular functions, even if they continued the running training over a year.
ABSTRACT
In this study, energy consumption of three types of basic rope skipping was measured, together with an investigation of work intensities. The subjects were 5 healthy adult male. The results of this study were as follows :<BR>1) The average relative metabolic rate (RMR) of 1 skip (one skip to one forwardturn of rope), 2 skip (double skip to one forward-turn of rope) and running skip were 13.6, 11.7 and 10.3, respectively, and it was noted that work intensities decrease in order of 1 skip, 2 skp and running skip.<BR>2) On the three types of five minute rope skipping, the oxygen intake for the last one minute of exercise of 1 skip was equivalent to 63.7-78.0% of maximal oxygen intake, and in cases of 2 skip and running skip were 57.5-76.3% and 56.8-67.2%, respectively.<BR>3) When skip frequencies of 1 skip were 92, 120 and 156 skips/min, respectively, oxy-gen requirement for 120 skips/min was the lowest, therefore, it was noted that skip fre-quency of 120 skips/min was optimal.
ABSTRACT
Studies were made on the physical fitness and morphological development of 47 high ranking sumo wrestlers who are considered to possess gigantic physique and great strength.<BR>Morphological measurements.<BR>1) The average body height was 180.2cm which when compared to the average Japanese is remarkably tall, however, when considering the tendency for the first rate athletes in Judo, boating, baseball, and basket ball to become taller, recently, this is not particularly noteworthy (Fig.1) .<BR>2) The average body weight was 122.3kg, and the average of the Rohrer's index was 210.5. This is remarkable and may be considered to be a characteristic of the sumo wrestlers (Table 1, Fig. 2) .<BR>3) The development of the circumf erential measurements when compared to that of the long axis of the body was remarkable : waist girth, 114.9cm, and hip girth 115.7cm. The skinfold thickeness was 109.9mm which is remarkably thick. This nearly abnormal development of subcutaneous fat is a special characteristic of sumo wrestlers.<BR>Physical fitness.<BR>4) The average back strength was 181.2kg, and the average grip strength was 47.9 kg, which are unexpectedly small and inferior to those of the boating and heavy weight lifting Olympic athletes. The method of measurement of muscle strength may be somewhat problematic, however, the development of the muscles was surprisingly poor. (Table 4)<BR>5) The sumo wrestlers were also remarkably poor in tests requiring body movement, such as, vertical jump (47.9 cm) and side step test (35.1 times) . These values are far inferior to those of athletes in other sports, and are even inferior to those of the average Japanese of comparable age. (Table 4)<BR>6) However, in spite of their obesity, the sumo wrestlers were comparable to the athletes of other sports in body flexibility and response time. (Table 4)<BR>7) Obese subjects are said to have weak respiratory function. The sumo wrestlers under observation had an average vital capacity of 4918.6m1 indicating a remarkably low value for their large physique.<BR>8) The average points for the step test was 49.4 indicating a lower value than the average Japanese of comparable age.<BR>9) A follow-up study of the measurements made during the past 4 years was made on a few Sekitori. Although no change was noted in body height, marked increases in body weight and circumferential measurements were observed. (Fig. 4)<BR>10) When the higher ranking wrestlers were compared with the lower ranking wreatlers, it was found that, morphologically, the higher ranking wrestlers were superior in body weight and circumferential measurements, however, no significant difference was found in the functional aspect (Fig. 5, 6) . These facts suggest that morphological superiority is an important factor in winning a sumo match.<BR>11) From the foregoing, it may be inferred that the special characteristic of the sumo wrestler is their well developed morphological features, especially girth, however, they are far inferior to athletes of other sports in their functional aspect. These points suggest that more consideration should be made on the sumo wrestlers' method of training and also on their mode of living.
ABSTRACT
The oxygen consumption during physical exercise is necessarily dependent upon the load on the muscle and also on the mass of muscles at work. In the present study maximal work has been performed by legs and arms plus legs in pedaling bicycle ergometer.<BR>Thirteen healty male students were studied. Group A consisted of eight Judoists, aged 18-21 years. Mean maximal oxygen uptake and max O<SUB>2</SUB> uptake/kg for this group were obtained 3.41/min and 44.7 ml/kg/min respectively in legs bicycle exercise. Group B consisted of five long distance runners, aged 19 years, with mean max. O<SUB>2</SUB>-uptake of 3.31/min and max. O<SUB>2</SUB>-uptake/kg of 57.2 ml/kg/min.<BR>In arms plus legs bicycle exercise, max. VO<SUB>2</SUB> and max. VO<SUB>2</SUB>/kg were an average value of 3.81/min and 49.8 ml/kg/min respectively for group A. For group B max. VO<SUB>2</SUB> and max. VO<SUB>2</SUB>/kg averaged 3.61/min and 62.6 ml/kg/min respectively.<BR>Group A 12% significantly higher values for max. VO<SUB>2</SUB> was attained in arms plus legs cycling (P<0.01), but group B 9% higher max. VO<SUB>2</SUB> when arms plus legs cycling than when legs cycling was actually not a regular finding in the group. Max. VO<SUB>2</SUB>/kg in legs cycling was an average 9-11% lower than that on arms plus legs cycling. The differences were statistically significant for group A and group B.<BR>Only in group A was max. VO<SUB>2</SUB> a little higher than in group B for legs cycling, but the differences was not statistically significant. Max. VO<SUB>2</SUB>/kg was statistically significantly higher in arms plus legs cycling with both group. In group A max. heart rate, tidal volume and O<SUB>2</SUB>-pulse were higher in arms plus legs cycling. Then max. heart rate and tidal volume were significantly higher in group A than on group B.