Validity of ???generalized??? equations for body composition analysis in male athletes

Abstract

Equations by Durnin and Womersley [(D-W)], Jackson and Pollock [(J-P)], and Lohman [(L)] for estimating body density (BD) purportedly overcome the problem of specificity by accounting for age and/or the curvilinear relationship between skinfolds (SF) and BD. Their equations were validated on 265 male athletes against percent fat measured by underwater weighing [(UWW); mean .+-. SD = 9.2 .+-. 4.4%]. Equations by Sloan [(S)] Katch and McArdle [(K-M), Human. Biol. 45:445, 1973], and Forsyth and Sinning [(F-S)] were included as linear regression models to compare to the curvilinear models of J-P, D-W and L. Differences between UWW and estimated mean values ranged from -1.1 to +5.9%; correlations ranged from 0.58-0.85; SEE [standard error of the estimate] ranged from .+-.2.41 to .+-.3.61%; and total error (E) ranged from 2.38-6.97%. The 7 D-W equations overestimated mean percent fat by from 3.9-5.9%. The K-M, S, and L equations overestimated by 1.3, 0.5 and 1.7%, respectively. The F-S equations overestimated by 2.4-3.8%. Of the 21 equations evaluated, only 3 by J-P gave estimates not significantly different from UWW percent fat. Regression analyses of the relationship between UWW (y) and estimated (x) percent fat values from those equations were: y = 1.037x - 0.08 .+-. 2.38, E = 2.38, r = 0.84; 0.869x + 1.36 .+-. 2.45, E = 2.51, r = 0.83; 1.107x - 1.14 .+-. 2.51, E = 2.53, r = 0.82. The 3 J-P equations were most accurate and suitable for body composition screening of male atheletes. The estimations by the S, K-M and L equations were within the error of the method.