The effects of contraction strength on the power spectrum of surface electromyogram (EMG) were studied during isometric contration of elbow flexion. Seven subjects sustained weights ranging between 2 kg and nearly maximum voluntary contraction strength at the wrist at the elbow joint angle of 90 degrees. Surface EMG of muscle biceps brachii was transfered to frequency power spectrum. The power spectrum was divided into four parts by the effects of contraction strength : below 50Hz, 50-80Hz, 80-120Hz and over 120Hz. With the increase of contraction strength the relative power below 50Hz decreased significantly, the relative power between 50HZ and 80Hz tended to increase, the relative power between 80Hz and 120Hz tended to decrease, and the relative power over 120Hz showed unstable changes. The effects of contraction strength below 120Hz were explained connecting with the activity level of motor units and the synchronization level of motor units activities. The relative power over 120Hz was connected with the shape of individual spike of surface EMG.

抄録全体を表示

The Effect of Pressure in Lower Extremity on Psychological Characteristics Shigeki WATANUKI and Kazuo MIHIRA Faculty of Science of Living. Osaka City University. Sugimoto-cho, Sumiyoshi-ku. Osaka-city, 558 Japan The effects of pressure in lower extremity on psychological characteristics were measured by using the technique of psychometric method. Five young females served as subjects. Results were as follows. ( 1 ) The pressure sensation in the thigh was more sensitive than that in leg, especially pressured at high values (above 60mmHg). And moreover the pressure sensation in leg was decreased by pressuring the thigh. ( 2 ) The width of the cuff obtaining the minimum pressure sensation existed and it was 7cm and equal to the distance of 2 points with just noticeable difference. ( 3 ) Psychological distances between adjective words indicating pressure sensation were almost the same interval in both leg and thigh, but the pressure obtaining the same adjective words were smaller in thigh than in leg.

抄録全体を表示

The true response according to the concept of "anaerobic threshold" during a progressive incrementalload exercise, corresponds to the onset of blood lactate accumulation from a resting level, and it is called lactate threshold (LT). The measurement and analysis of blood lactate, however, is complicated and not popular, so LT is often estimated by 2 criteria of gas exchange parameters (GEPs) described below visually, 1) non-1inear increase in V_E and 2) increase in V_E/V_O_2 Without corresponding increase in V_E/V_CO2, and it is called ventilatory threshold (VT). The visual inspection to detect VT contains the subjective variation of intra and inter-detectors, so its reliability and reproducibility are poor. The purpose of this study are 1) to examine if the LT is consistent with VT determinated by the modeling of each criterion to avoid the subjective variations, or not, and 2) if either of VT by modeling is consistent with LT well, to develop the new method (algorithm) that executes the estimation of its consisted VT by on-line and real-time processing of GEPs. 21 young male subjects performed an incremental-load ergometer exercise in which the initial work rate was the 4 min unloaded cycling and thereafter its rate was increased 150 kgm every 2 min until exhaustion. GEPS were measured by Douglas bag method continuously, and blood samples for lactate analysis were obtained last 30 sec of each work rate frofn a warmed ear lobe. To detect LT and VT from criterion l, we employed the segmented regression analysis to the data below 85% of V_O_2max of LA and V_E vs. V_O_2, and these were called LT and VT(85%). To detect VT from crit-erion 2, we employed the multiple regression analysis to all data of V_E/V_O_2 vs. V_O_2, and selected the model's order according to AIC. The lowest value of the fitting model was determinated as VT detected by criterion 2, and it is called "V_E/ V_O_2>(lowest)". ' As a result, VT(85%) was not always consistent with LT, but V_E/V_O_2(lowest) was consistent with LT well, so V_E/V_O_2(10west) was a good predictor to estimate LT by GEPS objectively. The consistence of LT and V_E/V_O_2(lowest) shows the cause-effect relationship between LT (cause) and VT (effect). It is not safe to perform the exercise test until exhaustion, in particular, for older subjects. So, it is necessary to develop the algorithm that executes the on-line and real-time processing of V_E/V_O2 data successively during a test. This algorithm can be stopped a test at the time of LT estimation. To consider the on-Iine and real-time processing, we use the point at whlch the slope between 2 adjacent V_E/V_O2 Changes from minus to plus, that equals V_E/V_O_2(lowest) substantially, and it is called "V_E/V_O_2(minimum)". To be concrete, this algorithm consists of three parts : moving average processing of V_E/V_O_2(raw data), calculation of the slope between 2 adjacent moving averages, and decision of V_E/V_O_2(minimum) using the change in slope.

抄録全体を表示

Using 63 males aged from 9 to 68 years and 70 females aged from 9 to 56 years in good health, pulmonary diffusing capacity for CO (D_L), diffusing capacity of the pulmonary capillary membrane (Dm), and pulmonary capillary blood volume (Vc) were measured in the sitting and supine positions and the age, sex, and ethnic differences in DL were studied. The subjects were divided into six groups by age as follows : Group I (9-12 years), Group 11 (16-25 years), Group III (26-35 years), Group IV (36-45 years), Group V (46-57 years), and Group VI (60-68 years). Group VI consisted of the males only. Regardless of age and sex, D_L indicated a close relationship with the alveolar volume (V_A'). The decreasing tendency of D_L with age was more remarkable in the supine position than in the sitting position, and the degree of the decrease was greater in males than in females. As to Dm and Vc comprising D_L, both showed an influence on age-related changes in D_L in males, while such influence mainly due to Vc in females. Sex difference in pulmonary diffusing capacity per stature (D_L/ST) was already observed in Group I, being greater in males. D_L/ST was greater in males than in females throughout Groups I to IV, however, the sex difference disappeared in Group V. Pulmonary diffusing capacity per alveolar volume (DL/VA') which showed no sex difference in Groups I to IV, was greater in Group V of females than in that of males. The greater D_L/ST in males seemed to be derived from a difference in alveolar volume per stature while the greater _DL/ V_A' in females seemed to be derived from a difference in age-related changes in pulmonary structure and function. Between the result of the present study and those of other reports on Caucasians (or those so considered), D_L and D_L/V_A' corrected by age and stature were compared. As the result in the young adult groups of 11 and 111, either males or females showed smaller D_L in Japanese than in Caucasians, but D_L/V_A' was nearly the same. The slopes of DL and D_L/V_A' against age were smaller in Japanese, for both males and females, thus in Group V for middle or old age, the difference in D_L was smaller or even disappeared, while D_L/V_A' tended to be greater in Japanese.

抄録全体を表示

Cardiac output (Q) was determined by the CO₂ rebreathing method in 85 Japanese subjects, from 10 to 55 years of age, during submaximal exercise. Q for adult females was not signifi-cantly different from that for adult males. Values of Q for boys, girls, and older adult males were significantly lower than that for the younger adult males at a given oxygen uptake (Vo₂) level. The relationship between Q at 1.0 l/min Vo₂ (Q_1.0) and body weight was examined for all the available data including those for various foreigu populations in literature. It was found that the groups with a large body weight tended to have a high value of Q. Thus, body size in some way influences Q during submaximal exercise even when metabolic levels are identical, and the differences in Q between males and females or adults and children are thought to be closely related to differences in body size. Although siguificant correlation was found between Q_1.0 and body size for all subjects in this study, older adult males had comparatively lower Q for their body size. The cardiovascular system of middle-age people is considered to differ from that of the younger persons.

抄録全体を表示

An inexpensive computer-digitiser system was developed for image and statistical analysis. This system, "PISA", composes of a 16-bit personal computer with 2 disk drives, a CRT color display, a dot printer and a digitiser. The softwares of the system provide the convenient operation programs for the data files and a variety of solution programs for those analyses. The softwares designed for user's particular needs also can be easily added to the system. The morphological factors, i.e. area, Iength, number, coordinates, are read by the digitiser, and are loaded into the memory of computer by way of RS-232C interface. The memory capacity for morphological data is more than 8000, which is expandable by adding up to RAM modules in the computer. A series of loaded data is saved on a floppy disk as a data file. Various analyses of images or statistics are, then, performed with the softwares registrated on system disk of "PISA".

抄録全体を表示