The propriety of the autoregressive (AR) method as a means of processing the signals of physiological tremor of human finger (finger tremor) was investigated. Application of the Akaike's criterion demonstrated that the 15-th order AR model was required to describe the recordings of finger tremor. According to Burg's algorithm, both AR spectrum and AR parameters were estimated to study the effccts of various weight loads on finger tremor. It was found that, (1)The amplitude of AR spectrum was apparently enhanced by adding the load; (2) the first prediction coefficient (a1) and the first reflection coefficient (p1) significantly declined by increasing the weight loads. The results were compared with the calculations from FFT (Fast Fourier Transform) and autocorrelation function. Simple physical interpretation of the AR parameters (i. e. a1 and p1) was discussed in relation with system's resonant modes.
The lumbar lodosis and pelvic tilt of twenty male subjects were measured in standing and in three different sitting postures with the trunk-thigh angles of 120 (sitting A), 90 (sitting B), and 60 (sitting C) degs and the knee angle was constant at 90 deg. Ten more male subjects participated in the supplemental study, in which additional condition of the knee angle was employed in postures of the trunk-thigh angles of 90 and 60 degs. Some joint mobilities were also measured to investigate the relations of the mobilities to lumbar lordosis and pelvic tilt. The lumbar curve decreased and the pelvis rotated rearward significantly as the trunk-thigh angle and the knee flexion decreased. The great alteration of the lumbar curve was observed between standing and sitting A, which was much different from the results of Keegan (1953) studied in the subjects of lateral recumbent position. There was a high correlation coefficient between the lumbar curve and the pelvic tilt (r=0.909), so that the relations of the pelvic tilt to the joint mobilities were investigated. When the knee angle was constant, the pelvic tilt is related significantly to the hamstrings between standing and sitting A and to the gluteus maximus between sitting A and sitting C. However, at different sitting postures with the trunk-thigh angles of 90 and 60 degs involving different knee flexions, hamstrings added to gluteal muscles affected significantly lumbar curve and pelvic tilting. It was con= cluded that the different sitting postures produced flexion of the spine through pelvic inclination caused by different hip extensors to an extent dependent upon the trunk-thigh angle combined with the knee angle.
Twenty-three children (12 boys and 11 girls) and 13 female students served as the subjects in summer. The children were from six to eight years old. The subjects were seated in a hot room of 30°C and their legs were immersed in bath water of 42°C for 30 minutes. Total sweat rate, Iocal sweat rate on the back, rectal temperature, skin temperatures at eight sites, heart rate and blood pressure were measured during the experiments. Total sweat rate of both groups was similar, but 10cal sweat rates of the children were significantly smaller than those of the students. Although the degree of increase in rectal temperature from immersion in the hot bath were similar, the increases of heart rate and skin temperatures on the thigh and forearm were greater in children. These results suggest that the thermoregulatory ability of children during heat exposure is similar to that of young female adults. However, it is found that for heat loss, children resort more to vasodilation than sweating during heat exposure as compared to adults. The children were divided into two groups according to whether the children were exposed to air cooling systems in summer in their infancy or not. There was no significant inter-group differences in physiological responses during immersion in the hot water bath. It is found that the ability of Japanese children to tolerate heat was not reduced distinctly by the frequent use of an air cooling system in infancy.
In this study, block data structured autoregressive (AR) method is used to evaluate fatigue, based on physiological tremor during and after loading a weight mass on the index finger. The temporal changes in the prediction coefficients and the reflection coefficients are determined. AR spectral estimation with the ninth-order is obtained and presented in graphical form. The results indicate that the first prediction coefficient a1 can be used to characterize the state of fatigue of finger muscle and the other prediction coefficients do not show any tendency for the finger load. The coefficient a1 can be applied to monitor the accumulative fatigue induced by the weight loading for a duration of time.
The effect of pseudo-fraction gravity on physiological tremor of the human finger (finger tremor) has been examined experimentally by immersing an index finger into water at different immersion levels. The pseudo-fraction gravity, γG, was established by water buoyancy at immersion levelΩ, G being gravitation acceleration and γ between zero and unit. The nature of variations of finger tremor under the influence of γG is estimated based on FFT spectral analysis. It is illustrated that with a decrease in γ, or equivalently an increase in Ω, two dominant peaks remaining approximately constant in frequencies around 10HZ and 20HZ are found, while peak amplitude is decreased rapidly for higher peak and slowly for lower one. Theoretically the effect of pseudo-fraction gravity is analyzed in terms of a specific model for finger tremor. The experimental results presented in this paper are predicted rather well by two resonant modes which occurred in our model system. It is possible to conclude that the model, which is characterized by a pair of antagonistic muscles and two reflex pathways, provides an adequate quantitative description of finger tremor.
Five male subjects performed steady exercise on a cycle ergometer at an intensity of 60% maximal 02 uptake (V02max) for 6 min on three separate occasions while breathing gas mixtures of 12, 16 or 21% 02 in N2 Expired gas fractions, ventilation, heart rate, arterial 02 saturation (Sa02), blood lactate (La) and plasma catecholamines (epinephrine: E and norepinephrine: NE) were measured. 02 uptake (V02) was calculated for the last minute of exercise. Blood samples were drawn at rest and immediately after exercise. By inspiring hypoxic gas mixtures, the Sa02 value decreased during exercise to 85.0±5.4 (16%) and 66.4±4.1 (12%) from 95.0±0. 1 in normoxia. V02 during exercise was not different among the three conditions. Exercise-induced La accumulation was increased by hypoxia. E and NE during exercise were not affected by hypoxia statistically. There was a significant correlation between La and E (P<0.01) and between La and NE (P<0.01) during exercise in the three conditions. The present findings suggest a relationship between glycogen metabolism and sympathoadrenal activity which results in an increase of plasma catecholamines during exercise in humans acutely exposed to hypoxia.
We examined the body shape of female athletes in comparison with female adult non-athletes by factor analysis. The subjects were 433 adult non-athletes and 464 athletes participating in 11 different sporting events. The physique, skinfold thickness and body composition of each subject were measured. The values obtained from non-athletes were analyzed by factor analysis, and the body shape of the athletes was then analyzed according to these factors. Four main factors with which 80 percent of total variance could be ex-plained were body fat (Factor 1), mass (Factor 2), Ieg length to height ratio (Factor 3) and length (Factor 4), and were extracted from the values from non-athletes. The body shape of the athletes could be classified into 4 categories by cluster analysis for factor score of sporting events: Iess body fat and slim type, average type like non-athletes, muscular and well-balanced type, and tall and well-developed mass. Compared with non-athletes, female athletes for all sporting events had less body fat. Moreover, the athletes had a body shape suitable for their sporting events; i. e., their mass, Iength of leg and height.