Replacing school and out-of-school sedentary behaviors with physical activity and its associations with adiposity in children and adolescents: a compositional isotemporal substitution analysis

Table 1 Descriptive characteristics of the study sample

	Boys (n = 128)		Girls (n = 208)		p value^c
	Mean^a	var^b	Mean^a	var^b	p value^c
Age (years)	14.4	2.4	13.8	2.6	0.033
Height (cm)	167.0	14.4	158.3	11.9	< 0.001
Weight (kg)	58.6	17.5	51.4	13.1	< 0.001
Fat mass (%)	15.5	7.6	23.7	8.0	< 0.001
Fat mass index (kg/m²)	3.4	2.4	5.0	2.5	< 0.001
Weight status (% of n)^d
Underweight	2.3		1.0		0.341
Normal weight	74.2		76.4		0.649
Overweight	14.8		18.3		0.407
Obese	8.7		4.3		0.099
24-h movement behaviors (min/day)^d
Sleep (min/day)	479.1	15.0	486.3	13.7	0.989
SB school (min/day)	229.4	19.1	215.2	19.6	0.236
SB out-of-school (min/day)	427.5	17.9	394.9	17.1	0.056
LPA school (min/day)	89.4	13.9	90.5	13.6	0.634
LPA out-of-school (min/day)	142.0	14.7	159.9	13.9	0.011
MPA school (min/day)	23.5	13.9	26.3	15.8	0.005
MPA out-of-school (min/day)	44.4	13.5	62.4	13.7	< 0.001
VPA school (min/day)	2.4	28.8	1.6	34.7	< 0.001
VPA out-of-school (min/day)	2.3	63.2	2.9	57.9	0.153

LPA light physical activity, MPA moderate physical activity, SB sedentary behaviors, VPA vigorous physical activity
^aGeometric mean for time-use components; arithmetic mean for non-compositional continuous variables; percentages for categorical variables
^bThe part of total variance related to a given time-use component; standard deviation for other variables
^cDifferences between sexes were tested using the t-test for independent samples and the chi-squared test for categorical variables
^dBased on the BMI z-score

ISSN: 1347-4715