The purpose of this study was to evaluate the relationship between the position of the center of foot pressure (CFP) and control of standing posture in ten healthy men by tracking the CFP to the moving target. Subjects were required to track a continuously moving target displayed on a screen while standing on a force plate. The velocity of the target movement was 0.05, 0.10, and 0.15 hertz (Hz) with a triangular waveform. The target was moved 30-70% within the range of the heel regarding the foot length as 100%, and the range was divided by 10%. Each subrange was named (A), (B), (C), (D) for backward movement from 70% to 30%, and (E), (F), (G), (H) for forward movement from 30% to 70%. The standing posture control was analyzed by mean error and absolute error at turning point between target- and CFP-movement. The mean error of backward movement was significantly greater than that of forward movement in the two forward subranges at 0.15 Hz. As for the other frequencies, there was no significant difference between directions of CFP movement. Mean error of A was significantly greater than that of B and C in higher frequencies, but there was no significant difference at 0.05 Hz. Regarding absolute error, there was no significant difference between the forward and backward turning point with a decrease in frequency. Mean error of D or E was greatest among the section in all frequencies. The ratio of the greater D or E and A or H was greatest at 0.05 Hz. These results suggested that CFP tracking at 0.05 Hz is hardly influenced by direction and velocity of the target movement. Terefore, we conclude that controllability of the stand-ing posture differs markedly in various CFP positions. In addition, control of the standing posture in a backward direction is inferior to that in a forward one.
Several prediction equations for estimating body composition of Japanese men and women have recently been developed using a linear regression model with a combination of impedance and anthropometric measurements as independent variables. The purpose of this study was to determine the cross-validity of body density (Db) estimated from bioelectrical impedance (BI) and skinfold thickness (ST) methods in comparison with underwater weighing (UW) as a criterion reference method. Percentage body fat (%BF) was derived from Db according to the equation Brozek et al. Fifty-seven healthy Japanese women, aged 19 to 57 years, volunteered to participate in the study. Impedance was measured by use of a portable four-terminal impedance plethysmograph (Selco, SIF-891) . %BF derived from the BI method (r=0.860-0.875) was correlated with hydrodensitometrically determined %BF to a greater extent than %BF obtained using the ST method (r=0.7330.758) or ultrasound method (r=0.536-0.721) . Correlations of various anthropometric indices (r=0.655-0.691) with hydrodensitometrically determined %BF were even lower. It was noteworthy, however, that mean %BF derived from existing BI equations differed significantly from hydrodensitometrically determined mean %BF. Therefore, we attempted to develop a new equation that was applicable to Japanese adult women as follows: Db=1.1613-0.1038 (Wt⋅Z ) /Ht2, where Wt=weight in kg, Z=impedance in ohms, and Ht=height in cm. The prediction accuracy of this equation was r=0.866 or SEE=0.0077 g/ml. Cross-validation of this equation on a different sample (122 Japanese women, aged 18 to 59 years) revealed a correlation of r=0.869 in terms of %BF, SEE=3.2%, and no significant difference between estimated %BF and the criterion. We suggest that the BI method is one of the most convenient, valid means of assessing human body composition, and that the newly developed BI equation could be useful particularly when the subjects are Japanese adult women in their late teens to fifties.
The purpose of the present study was to investigate the relationships of physical fitness, body mass index (BMI), waist-hip ratio (WHR) and sex hormone binding globulin (SHBG) with lipid and glucose metabolism in premenopausal obese women aged 32 to 49 yrs (n=24) . WHR was significantly correlated with HDL-C, HDL2-C and Apo B, but not correlated with BMI %fat, maximal oxygen uptake (VO2max), triglyceride (TG), very low density lipoprotein % fat, and Apo A 1. VO2max/kg was significantly associated with BMI, TG, HDL-C, HDL2-C, Apo Al, low density lipoprotein (LDL), SHBG, glucose metabolism at rest and during oral glucose tolerance test (OGTT) . The SHBG was strongly correlated with HDL-C, HDL2-C and Apo A 1. In multiple regression analysis, it was observed that SHBG was one of the independ-ent predictor of HDL-C, HDL2-C and Apo Al, that VO2max was good predictor of LDL, Apo B and glucose metabolism at rest and during OGTT, and that BMI was one of the determinat of TG and VLDL. From these results, we concluded that lipid metabolism was independently associated with aerobic work capacity, SHBG, BMI as well as WHR, and that glucose metabolism was independently associated with aerobic work capacity.