Abstract
Body densities and skinfold thicknesses of 105 boys and 89 girls aged 9 to 14 years were measured, and the regression equations for predicting the body density from the skinfolds were proposed.
Body density was determined by the water displacement volumetry. The skinfold thicknesses were measured at two sites of triceps and subscapula by using an Eiken-type Caliper (devised in our Institute) calibrated to exert pressure of 10gm/mm2.
The average values of body density in boys were 1.0621 for 9-11 years old and 1.0566 for 12-14 years old and in girls were 1.0490 for 9-11 years old and 1.0523 for 12-14 years old (Table 2).
The correlation coefficients between body density and skinfolds were similarly higher in correlation with the triceps skinfold and the combined skinfold of [triceps+subscapula] and with the skinfold index expressed as [skinfold×body surface÷body weight], as compared with the low coefficient values in subscapular skinfold. The correlations between body density and physique indices of W/H2 and W/H3 were lower as compared with the coefficients in the skinfolds (Table 3).
The regression equations for predicting the body density from the skinfolds are given in Tables 4, 5 and 6. Among these equations, equation No. 3 for boys and No. 7 for girls are simpler and useful, and equations No. 4 and No. 8 by using the skinfold index are more reliable. The reliability by using the skinfold index lies in eliminating the erroneous element under the influence of individual difference of body height or muscular mass in estimation of the body density and body fat content by the simple use of skinfolds.
