Table 2.

Associations of body composition with physical fitness in 9-year-old children.

Body composition (x)	Fitness variables (y)	Unadjusted		Adjusteda
		β	P	β	P
BMI (kg/m2)	Cardiorespiratory fitness	− 0.307	< 0.001	− 0.306	< 0.001
	Upper body strength	0.408	< 0.001	0.467	< 0.001
	Lower body strength	− 0.243	< 0.001	− 0.219	< 0.001
	Motor fitnessb	− 0.235	< 0.001	− 0.224	< 0.001
FM (%)	Cardiorespiratory fitness	− 0.470	< 0.001	− 0.431	< 0.001
	Upper body strength	0.131	0.008	0.209	< 0.001
	Lower body strength	− 0.452	< 0.001	− 0.402	< 0.001
	Motor fitnessb	− 0.415	< 0.001	− 0.385	< 0.001
FMI (kg/m2)	Cardiorespiratory fitness	− 0.425	< 0.001	− 0.439	< 0.001
	Upper body strength	0.223	< 0.001	0.144	0.002
	Lower body strength	− 0.403	< 0.001	− 0.446	< 0.001
	Motor fitnessb	− 0.384	< 0.001	− 0.452	< 0.001
FFMI (kg/m2)	Cardiorespiratory fitness	0.040	0.42	0.141	0.005
	Upper body strength	0.537	< 0.001	0.495	< 0.001
	Lower body strength	0.150	0.002	0.278	< 0.001
	Motor fitnessb	0.139	0.005	0.286	< 0.001

β, standardized regression coefficient; BMI, body mass index; FFMI, fat-free mass index; FM, fat mass; FMI, fat mass index.

^aAdjusted for child’s age and sex, maternal educational level and maternal BMI (for models with FMI and FFMI as independent variables, the models were also mutually adjusted for FMI and FFMI).

^bSince lower scores indicate higher performance, results are inverted.