Resumen de Use of B-Mode Ultrasound as a Body Fat Estimate in Collegiate Football Players

Parker N. Hyde, Kristina L. Kendall, Ciaran M. Fairman, Nicholas A. Coker, Mary E. Yarbrough, Steve J. Rossi

• The purpose of the present study was to validate a 7-site ultrasound imaging protocol to predict the percent body fat (%BF) in a division I football team. Body composition was estimated by ultrasound, 7-site skinfolds, and the 3-compartment-water (3C-W) model of Siri, using bioimpedance spectroscopy to estimate the total body water and air displacement plethysmography (using BODPOD) to determine the body density. Pearson's product-moment correlation analyses were run to determine correlations between [SIGMA]Ultrasound and the criterion 3C-W, and between the [SIGMA]Skinfold and [SIGMA]Ultrasound. Strong positive correlations were observed between [SIGMA]Skinfold and [SIGMA]Ultrasound (r = 0.984; p < 0.001). Furthermore, a strong positive correlation was observed between [SIGMA]Ultrasound and %BF from 3C-W (r = 0.878; p < 0.001). Based on the significant correlation analysis, a linear regression equation was developed to predict the %BF from [SIGMA]Ultrasound, using %BF from the 3C-W model as the dependent variable: %BF = 6.194 + (0.096 × [SIGMA]Ultrasound); standard error of the estimate (SEE) = 2.97%. Cross-validation analyses were performed using an independent sample of 29 players. The mean observed %BF from the 3C-W model and the mean predicted %BF were 18.32 ± 6.26% and 18.78 ± 6.22%, respectively. The constant error, SEE, and validity coefficient (r) were 0.87%, 2.64%, and 0.91%, respectively. The total error was 2.87%. The positive relationship between ultrasound measurements and the 3C-W model suggests that ultrasound imaging may be a practical alternative to predicting %BF in division I football players.