Abstract
The purposes of this investigation were to (a) modify the y-intercepts of previously published skinfold (SF) equations using the constant error (CE) values from Stout et al. (24); (b) cross-validate the modified equations to determine their accuracy for estimating body density (BD) in young wrestlers; (c) derive a new SF equation for estimating BD in young wrestlers, if the modified equations are not found to be accurate; and (d) cross-validate the new SF equation on an independent sample of young wrestlers. One hundred thirty-seven age-group wrestlers (mean ± SD age = 11.3 ± 1.6 year) volunteered to perform underwater weighing for the determination of BD and to have SF measured at 8 sites. Cross-validation of the 16 modified SF equations on a random sample of 50 subjects resulted in total error (TE) values that were ≥ 0.0110 g·cm-3 (approximately 5.1% fat). Therefore, the following SF equation was derived on a random sample of 100 of the subjects: BD = 1.056-0.00098 (triceps SF) + 0.00132 (age in years)- 0.0017 (anterior suprailiac SF) + 0.00031 (body weight in kg). R = 0.78, SEE = 0.0064 g·cm-3. Cross-validation of this equation on an independent sample of 37 subjects resulted in a nonsignificant (p > 0.05) CE of -0.0009 g·cm-3, a validity coefficient (r) of 0.70, SEE of 0.0076 g·cm-3, and TE of 0.0076 g·cm-3. Therefore, this SF equation is recommended for estimating body composition characteristics in young wrestlers. Future studies should cross-validate this equation on young athletes in various sports.