Table 6.

Prediction equations for fat-free mass validated and cross-validated using a random split-group sampling.

Group A (n=128)
DEXA-measured FFM in kg	37.50±10.39
FFM prediction equation	2.275 + 0.728 × ZI + 0.148 × body weight R2=0.94, SEE=2.60, CV=7.4%, VIF=5.7
BIA-predicted FFM in kg	37.50±10.07
Cross-validation using group B samples FFM	37.58±10.25, RSME=2.60, CV=6.9%
Group B (n=127)
DEXA-measured FFM in kg	38.17±10.87
FFM prediction equation	1.351 + 0.696 × ZI + 0.192 × body weight R2=0.94, SEE=2.69, CV=7.1%, VIF=7.6
BIA-predicted FFM in kg	38.16±10.53
Cross-validation using group A samples FFM	37.99±10.24, RSME=2.70, CV=7.1%

FFM – fat-free mass; ZI – impedance index = height²/Z; SEE – standard error of estimate; CV – coefficient of variation; VIF – variance inflation factor; RSME – root mean square error.