Seljebotn 2019.

Study characteristics
Methods	Study design: cluster‐RCT
Participants	School inclusion criteria: all primary schools in the municipality of Stavanger, Norway School exclusion criteria: — Student inclusion criteria: Grade 5 ‐ 9 to 10 years old Student exclusion criteria: — Setting: school Age group: children Gender distribution: females and males Country where trial was performed: Norway
Interventions	Intervention: physically active lessons (45 minutes) 2 to 3 days/week on days without PE. Lessons were held mainly outdoors and included games, relays, and quizzes with curricular questions from theoretical subjects. Physically active lessons included at least 15 minutes of MVPA, were easily organised and adapted, included competitive and non‐competitive elements, and were enjoyable activities that included all children. Secondary components included physically active homework (10 minutes/d) and physically active recess (10 minutes/d). The intervention was intended to increase the amount of PA by 190 minutes/week, giving a total of 325 minutes/week of PA. To further improve the quality of the physically active lessons, a quality framework was stated at the back of the physically active lesson form and included tips of how differentiation, autonomy, collaboration, enjoyment, and high activity level could be ensured. To assist and support intervention teachers, 1 primary and 1 secondary contact person from the Active School project team was assigned to each intervention school. Contact persons attended meetings and regularly visited participating teachers and classes throughout the school year (1 to 4 visits/month, depending on requests from the schools). 1 pre‐intervention seminar and 1 midway seminar were arranged for the teachers to give information about the programme and to provide support. New physically active lessons were shared between intervention schools through a website Comparator: control schools were asked to continue their normal routine, which included approximately 135 minutes/week of PA Duration of intervention: 10 months Duration of follow‐up: 10 months Number of schools: 9 Theoretical framework: —
Outcomes	PA duration Sedentary time Fitness BMI
Study registration	NCT03436355
Publication details	Language of publication: English Funding: non‐commercial funding (research funding body) Publication status: peer‐reviewed journal
Stated aim for study	"Based on current knowledge, the research question of this study is as follows: to what extent will increased PA in school affect children’s executive function and aerobic fitness?"
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote from publication: "the computer program 'Researcher Randomizer' was used to randomise the 2 groups into intervention and control groups"
Allocation concealment (selection bias)	Unclear risk	Comment: not stated
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: participants and study staff were not randomised [author communication]
Blinding of outcome assessment (detection bias) All outcomes	High risk	Comment: outcome assessors were not blinded [author communication]
Incomplete outcome data (attrition bias) Anthropometrics, Fitness	Low risk	Comment: low loss to follow‐up; unrelated to intervention
Incomplete outcome data (attrition bias) Physical activity and sedentary time	Low risk	Comment: low loss to follow‐up; unrelated to intervention
Selective reporting (reporting bias)	High risk	Comment: composite measure of executive function reported rather than individual components listed as primary outcomes
Cluster RCT ‐ Recruitment bias	High risk	Comment: randomisation before participant enrolment
Cluster RCT ‐ Baseline imbalance	Unclear risk	Comment: not stated
Cluster RCT ‐ Loss of clusters	Low risk	Comment: no clusters lost
Cluster RCT ‐ Incorrect analysis	High risk	Quote from publication: "due to low variance between schools in these outcomes, multilevel analysis was not considered necessary"