Group and individual agreement between field and dual X-ray absorptiometry-based body composition techniques in children from standard schools and a sports academy

Abstract

Percentage fat (%FM) and fat-free mass (FFM) were measured in 37 children from a sports academy and in 71 children from standard schools with dual x-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA) using the manufacturer's equation (Tanita) and an ethnic-specific prediction equation (Haroun). In the standard school, BIA overestimated FFM and underestimated %FM by a mean of 2.5 kg and 5.2%, respectively, using the Tanita equation. In girls from the sports academy, the Tanita equation underestimated FFM and overestimated %FM compared with DXA (mean difference BIA-DXA; FFM: -1.3 kg; %FM: 1.8%). The Haroun equation improved mean agreement between BIA and DXA in children (11 to 15 years) from the sports academy and for boys from standard schools, but reduced accuracy on individual assessments. These results have important practice implications for dietetics practitioners specializing in sports nutrition and exercise trainers.

Keywords: Body composition; Child athletes; Dual x-ray absorptiometry; Foot-to-foot bioelectrical impedance; Sports academy.