Offseason Body Composition Changes Detected by Dual-Energy X-ray Absorptiometry versus Multifrequency Bioelectrical Impedance Analysis in Collegiate American Football Athletes

Tracking changes in body composition may provide key information about the effectiveness of training programs for athletes. This study reports on agreement between bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) tracking during a seven-week offseason program 29 NCAA collegiate American football players. Body subjects (mean ± SD; age: 19.7 1.5 y; height: 179.8 6.6 cm; mass (BM: 96.1 12.6 kg; DXA fat: 20.9 4.4%) was estimated using BIA (InBody 770) (Hologic Horizon) before after intervention. Repeated measures ANOVA post hoc comparisons were performed. Longitudinal methods also examined by concordance correlation coefficient (CCC) Bland–Altman alongside linear regression to identify bias. Significant method time interactions observed BM (DXA: 1.1 2.4 BIA: 1.4 2.5 p < 0.03), arms fat-free (FFM) 0.4 0.5 0.2 legs FFM 0.6 0.1 0.01). Post indicated that DXA—but not BIA—detected increases legs. Time main effects, but no interactions, total 1.6 1.9 1.2 2.1 = 0.004) trunk 0.7 1.3 1.0 0.02). Changes (CCC 0.96), 0.49), fat 0.50) significantly correlated DXA. similarly track whole-body players; however, possess less sensitivity detecting segmental increases, particularly appendages.