VALIDITY OF BIOELECTRICAL-IMPEDANCE EQUATIONS FOR ESTIMATING FAT-FREEWEIGHT IN HIGH-SCHOOL FEMALE GYMNASTS

The present study examined the validity of bioelectrical impedance (BI A) equations for estimating fat-free weight (FEW) in female gymnasts b y comparing the values to those obtained from underwater weighing (UWW ). Ninety-seven female Caucasian high school gymnasts (X age +/- SD = 15.7 +/- 1.1 yr) participated in the study. FEW from UWW was calculate d from percent fat using the revised formula of Brozek et al. (5) (X F FW +/- SD = 43.8 +/- 4.5 kg) and the age-specific constants of Lohman (28) (X FFW +/- SD = 44.8 +/- 4.6 kg). Cross-validation analyses inclu ded examination of the constant error (CE), SEE, r, and total error (T E). The results indicated similar trends between equations when based on either the Brozek or Lohman conversions; however, the CE, SEE, and TE values were consistently lower for the majority of the equations us ing the revised formula of Brozek et al. (5). Based upon the results o f the cross-validation analyses, the equation of Houtkooper et al. (22 ) and the interlaboratory equations of Van Loan et al. (50) and Lohman (29), which resulted in identical TE values of 2.4 kg are recommended for use with young high school gymnasts.