Physical activity duration: additional data
Study	Study population	Intervention group	Control Group	Measurement period	Overall effect	Comment
Before and after school programmes
Zhou 2019	Junior high school students, grade 7	I1: Biweekly after school program	Regular PE (2 days per week)	32 weeks	% of time spent in MVPA: MD 1.99 (95% CI: 1.68, 2.30) I1: m 4.22 (sd 1.39) Control: m 2.23 (sd 1.52)	% time reported, not min/day
		I2: Enhanced PE (3 days per week) plus after school program	Regular PE (2 days per week)	32 weeks	% of time spent in MVPA: MD 4.98 (95% CI: 4.62, 5.34) I2: m 7.21 (sd 1.84) Control: m 2.23 (sd 1.52)	Authors note that statistically significant changes were found from baseline to follow‐up in both intervention groups but not the control group however analyses were not described.
Enhanced PE
Ten Hoor 2018	Secondary school students, 11 to 15 years old	Strength training and motivational interviewing	Usual curriculum	1 year	Between group difference in % of time spent in MPVA tested, P = 0.046	No values reported
Zhou 2019	Junior high school students, grade 7	I1: Enhanced PE (3 days per week)	Regular PE (2 days per week)	32 weeks	% of time spent in MVPA: MD 3.12 (95% CI: 2.76, 3.48) I1: m 5.35 (sd 1.79) Control: m 2.23 (sd 1.52)	% time reported, not min/day
		I2: Enhanced PE (3 days per week) plus after school program			% of time spent in MVPA: MD 4.98 (95% CI: 4.62, 5.34) I2: m 7.21 (sd 1.84) Control: m 2.23 (sd 1.52)	Authors note that statistically significant changes were found from baseline to follow‐up in both intervention groups but not the control group however analyses were not described.
Multi‐component intervention
Corepal 2019	Students age 12‐14	Pedometer challenge	Usual school	Baseline	Intervention: m 33.3 min/day, IQR: 23.6, 49.0) Control: m 43.6 min/day, IQR: 31.0, 69.3	Feasibility trial, therefore statistical testing not conducted
				22 weeks	MD: ‐14.4 min/day Intervention: m 33.0 min/day, IQR: 20.0, 46.2 Control: m 47.4 min/day, IQR: 32.7, 65.1	No estimates of variance given, only mean and interquartile range
Salmon 2008	Grade 5 students (10 to 11 years old)	I1: Behavioral modification group, I2: fundamental motor skills group, I3: combined behavioral modification and fundamental motor skills group	Usual classroom lessons	1 school year	Adjusted between group difference (vs. control group) I1: MD 2.8 (95% CI 0.3, 5.4) min/day I2: MD 7.8 (95% CI 3.4, 12.3) min/day I3: MD 3.1 (95% CI ‐0.58, 6.7) min/day	Vigorous PA only
				1 year post‐intervention	Adjusted between group difference (vs. control group) I1: MD 2.8 (95% CI 0.2, 5.4) min/day I2: MD 7.7 (95% CI 3.2, 12.2) min/day I3: MD 3.0 (95% CI ‐0.59, 6.6) min/day	Vigorous PA only
Schooltime PA
Ford 2013	Primary school students aged 5 to 11 years	Accumulated brisk walking program	Normal school lessons	15 weeks	Change from baseline MD ‐27.4 (95% CI: ‐91.0, 36.2) counts per min Intervention group: ‐29.2 (‐72.0, 13.6) counts per min, P = 0.415 Control group: ‐1.8 (‐50.3, 46.7) counts per min, P = 0.772	Weekday counts per min only
Magnusson 2011	Children attending grade 2 (born in 1999)	Students engaged in PA during PE lessons, recess, and during classes; schools had access to PA equipment to use in school lessons; teaching materials promoting PA were provided	Followed the general PA curriculum	1 year (midpoint)	Group x time interaction in multivariable model P < 0.0001
				2 years	Group x time interaction in multivariable model P = 0.10