Accuracy of DXA in estimating body composition changes in elite athletes using a four compartment model as the reference method

Table 2 Body composition variables at the period of stability, prior to competition, and respective differences

N = 27	Period of Stability	Prior to Competition	Changes
	Mean ± SD	Mean ± SD	Mean ± SD
%FM_4C	9.2 ± 4.1	8.0 ± 3.8	-1.22 ± 2.70^b
FM_4C (kg)	6.8 ± 3.3	5.9 ± 3.0	-0.94 ± 1.98^b
FFM_4C(kg)	66.1 ± 6.4	66.1 ± 6.0	0.07 ± 2.04
%FM_DXA	12.1 ± 3.1^b	11.7 ± 2.8^b	-0.41 ± 1.05
FM_DXA (kg)	8.8 ± 2.8^b	8.4 ± 2.5^b	-0.42 ± 0.93^a
FFM_DXA (kg)	63.4 ± 5.7^b	62.9 ± 5.8^b	-0.45 ± 1.55
FFM_D (g/cc)	1.100 ± 0.007	1.102 ± 0.009	0.002 ± 0.005
TBW/FFM	0.72 ± 0.02^c	0.71 ± 0.03^c	0.006 ± 0.016
M/FFM	0.057 ± 0.003^c	0.057 ± 0.004^c	0.000 ± 0.002
Protein/FFM	0.22 ± 0.02^c	0.23 ± 0.03^c	0.006 ± 0.016

Abbreviations: %FM: relative fat mass; FM: fat mass; FFM: fat-free mass; 4C: four-compartment model; DXA: dual-energy x-ray absorptiometry; FFM_D: density of fat-free mass; TBW/FFM: fat-free mass hydration; M/FFM: mineral fraction of fat-free mass; Protein/FFM: protein fraction of fat-free mass
*Changes are calculated as: prior to competition minus period of stability
^a Significant difference from the period of stability and prior to competition, p < 0.05
^b Significant difference from the reference method, p < 0.05;
^c Significant difference from the value obtained based on chemical cadaver analysis, p < 0.05 (FFM_D = 1.1 g/cc [7]; TBW/FFM = 0.738; M/FFM = 0.068; Protein/FFM = 0.194)

ISSN: 1743-7075