A 3-year school-based exercise intervention improves muscle strength - a prospective controlled population-based study in 223 children

Table 2 Physical activity

	Girls			Boys
	Cases (n = 47)	Controls (n = 46)	P- value	Cases (n = 76)	Controls (n = 54)	P- value
Baseline
Organized physical activity before study start (hours/week)
Total physical activity	1.7 (0.7)	2.4 (1.7)	0.02	2.7 (1.6)	2.3 (1.3)	0.18
Organized physical activity after study start (hours/week)
School curriculum	3.3	1.0	<0.001	3.3	1.0	<0.001
Outside School	0.7 (0.7)	1.4 (1.7)	0.02	1.7 (1.6)	1.3 (1.3)	0.18
Total physical activity	4.0 (0.7)	2.4 (1.7)	<0.001	5.0 (1.6)	2.3 (1.3)	<0.001
Follow-up (after 3 years)
Organized physical activity (hours/week)
School curriculum	3.3	1.0	<0.001	3.3	1.0	<0.001
Outside School	2.3 (2.0)	2.8 (2.5)	0.38	3.3 (3.3)	2.9 (2.4)	0.50
Total physical activity	5.6 (2.0)	3.8 (2.5)	<0.001	6.6 (3.3)	3.9 (2.4)	<0.001

Baseline and follow-up physical activity data in the subsample of girls and boys who were measured. Questionnaire-evaluated duration of organized physical activity was estimated as mean hours per week. Data are presented as mean with standard deviation (SD). Statistically significant group differences are bolded.