Table 1

Sociodemographics and preintervention measures of unmatched and PSM samples in study sample for physical fitness*

	Unmatched†		Missing data (%)	PSM‡
	Lekker Fit! group (n=693)	Regular school group (n=2302)	Missing data (%)	Lekker Fit! group (n=679)	Regular school group (n=1147)
Age (years), mean (SD)	6.17 (0.50)	6.06 (0.40)	5.8	6.15	6.16
Sex, %			0.0
Girls	52.2	50.8		52.1	51.2
Ethnicity, %			1.4
Native Dutch	42.7	69.3		43.7	43.5
Turkish	8.8	2.5		8.0	7.6
Moroccan	10.4	2.9		9.7	8.8
Surinamese	11.9	6.1		12.1	12.7
Antillean	4.2	2.4		4.3	4.3
Cape Verdean	4.9	1.9		5.0	4.9
Other	17.1	14.9		17.2	18.1
Maternal education level, %			12.9
High	21.4	33.9		20.3	20.8
Mid-high	23.1	31.1		24.0	24.2
Mid-low	37.1	28.0		37.6	37.6
Low	18.4	7.0		18.1	17.4
Paternal education level, %			20.0
High	25.3	39.4		21.5	21.4
Mid-high	18.7	25.2		18.7	19.0
Mid-low	33.3	24.7		33.1	33.4
Low	22.7	10.8		26.7	26.1
Net household income, %			17.5
<€2000/month	31.7	14.2		34.2	34.3
€2000–€3200/month	34.3	22.7		32.8	32.3
>€3200 /month	34.0	63.1		33.0	33.4
BMI-sds, mean (SD)	0.28 (0.96)	0.20 (0.86)	5.9	0.28	0.26
Sports participation, %			13.7
Yes	35.5	47.9		34.9	35.3
No	64.5	52.1		65.1	64.7
Outdoor play, %			15.0
<5 days/week	37.7	31.3		38.6	38.0
≥5 days/week	62.3	68.7		61.4	62.0
Weight status, %			5.9
No overweight	79.0	86.1		78.2^n.m.	81.8^n.m.
Overweight/obese	21.0	13.9		21.8^n.m.	18.2^n.m.

*Study sample for physical fitness contains participants with data on the outcome measure WRpeak z-scores.
†Non-imputed sample.
‡Imputed sample.
BMI, body mass index; n.m., sample is not matched on weight status, as it was matched on BMI-sds; PSM, propensity score matched.