Abstract

A study was conducted to investigate the validity of skinfold-based prediction equations for body density (Db, g/ml) developed by Nagamine et al. (1974), and to formulate useful equations for predicting Db by the skinfold thickness (ST) method in junior high school boys and girls. Subjects of the study were 269 healthy boys and girls (12-15 yr). The dependent variable, Db, was determined by underwater weighing (UW). Independent variables included single skinfold thickness at 3 sites (triceps, subscapular and abdomen) and the sum of 2 skinfolds. Db by the ST method was estimated from the equations developed by Nagamine et al. (1974) for boys and girls, using the sum of skinfold thickness at the triceps and subscapular area. Skinfold thickness was measured on the right body side with an Eiken-type skinfold caliper. Db estimated by the ST method was correlated significantly with Db determined by UW (r=0.873 for boys, r=0.723 for girls). However, average Db values estimated by ST method were significantly lower than those determined by UW (differences in Db values when predicted by the Nagamine equations: 0.0099 for boys and 0.0114 for girls). Therefore, we developed linear regression equations for predicting Db. The best-fitting prediction equation for Db was Db=1.0881 - 0.0010 X for boys, and Db=1.0715 - 0.0007 X for girls, where X is the sum of the triceps and subscapular skinfold thickness (mm) for boys and girls. Db estimated from the respective equation was correlated significantly hydrodensitometrically determined Db. Verf.-Ref.