Validity of anthropometric equations for the estimation of body density in adolescent athletes.

One hundred forty-one adolescent male (age: X +/- SD = 17.43 +/- 0.96 yr) and 133 adolescent female (16.51 +/- 1.39 yr) athletes were studied to determine the validity of available anthropometric equations for estimating body density (BD). Anthropometric measures were taken of eight skinfolds, nine circumferences, and four diameters. Body density, determined by underwater weighing (corrected for residual lung volume), was 1.080 +/- 0.010 g X ml-1 for the males and 1.066 +/- 0.010 g X ml-1 for the females. Cross-validation of 17 selected equations on the males revealed validity coefficients ranging from R2 = 0.29-0.67 and total-error scores ranging from 0.0062-0.0277 g X ml-1. Among the females, cross-validation of 15 selected equations revealed validity coefficients ranging from R2 = 0.31-0.67 and total-error scores ranging from 0.0064-0.0214 g X ml-1. While equations of either linear or quadratic form demonstrated acceptable accuracy in the estimation of male BD values, only quadratic equations displayed similar levels of accuracy among the females. Based on these results, as well as consideration of characteristics related to inter-tester error and the variance of predicted scores, the quadratic equations of Jackson and Pollock, Lohman, and Pollock et al., as well as the linear equation of Forsyth and Sinning, were found to be particularly appropriate for the estimation of BD in adolescent athletes.