Athletic bioimpedance-based equations underestimate fat free mass components in male elite soccer players: development and validation of new soccer-specific predictive models

Table 2 Developed bioelectrical impedance models for fat-free mass, total, and appendicular lean soft tissue predictions

	Unstandardized coefficient β	Standardized coefficient β	R²	SEE (kg)	VIF
Fat-free mass (kg)			0.97	1.04
Intercept	− 7.729
BM (kg)	0.686	0.774			1.48
S²/R (cm²/Ω)	0.227	0.268			3.98
Xc (Ω)	0.086	0.080			1.56
Age (years)	0.058	0.054			1.09
Lean soft tissue (kg)			0.96	0.99
Intercept	− 8.929
BM (kg)	0.635	0.751			3.42
S²/R (cm²/Ω)	0.244	0.301			3.99
Xc (Ω)	0.093	0.091			1.52
Age (years)	0.048	0.046			1.00
Appendicular lean soft tissue (kg)			0.88	1.35
Intercept	− 24.068
BM (kg)	0.347	0.561			3.46
S²/R (cm²/Ω)	0.308	0.521			3.98
Xc (Ω)	0.152	0.203			1.52

BM, body mass; S, stature (cm); R, resistance (Ω); Xc, reactance (Ω); R², coefficient of determination; SEE, standard error of the estimate; VIF, variation inflation factor

ISSN: 1479-5876