Abstract
The purpose of the present study was to determine the validity of near-infrared interactance (NIR) estimates of percent body fat (% fat) using Futrex-5000, Futrex-5000A, and Futrex-1000 instruments in youth wrestlers (age, M ± SD = 11.4 ± 1.5 years) by comparing them to % fat values from underwater weighing. Fifty-eight members of youth wrestling clubs (% fat, M ± SD = 10.7 ± 5.1% fat) volunteered to serve as subjects. The statistical analyses included examination of the constant error (CE), standard error of estimate (SEE), correlation coefficient (r), and total error (TE). The results indicated that the errors (TE = 8.0-16.2% fat) associated with the NIR instruments were too large to be of practical value for estimating % fat in young male athletes. It is recommended that (a) the instrument generated NIR % fat estimates be modified based on the CE values in the present investigation such that the CE = 0, and (b) the modified NIR % fat estimates be cross-validated on independent samples of young male athletes.