Kriemler 2010.

Study characteristics
Methods	Study name: KISS Study design: cluster‐RCT Intervention period: 9 months Follow‐up period (post‐intervention): 3 years Differences in baseline characteristics: reported Reliable outcomes: reported Protection against contamination: reported Unit of allocation: school Unit of analysis: individual accounting for clustering (class and school)
Participants	N (control baseline) = 205 N (control follow‐up) = 100 N (intervention baseline) = 297 N (intervention follow‐up) = 189 Setting (and number by study group): 28 classes from 15 elementary schools (16 classes from 9 schools in intervention group and 12 classes from 6 schools in control group) Recruitment: 15 schools were randomly selected from 95 schools; then 15 schools were randomly assigned into intervention Geographic region: 2/26 provinces of Switzerland (Aargau and Baselland) Percentage of eligible population enrolled: 15% schools Mean age: intervention: 6.9 ± 0.3 1st graders; control: 6.9 ± 0.3 1st graders; intervention: 11.0 ± 0.5‐ 5th graders; control: 11.3 ± 0.6 5th graders Sex: intervention: 52% female; control: 50% female
Interventions	To assess the effectiveness of a school‐based PA programme during 1 school year on physical and psychological health in young schoolchildren Multi‐component PA programme of 9 months including daily PE (i.e. 2 additional lessons/week on top of 3 regular lessons), short PA breaks during academic lessons, and daily PA homework. Children in both groups had 3 PE lessons/week, which are compulsory by law. The intervention group had 2 additional PE lessons on the remaining school days. A team of expert PE teachers prepared all 5 PE lessons for the children in the intervention group. All intervention classes received the same curriculum. The 3 compulsory weekly PE lessons (45 min each) were given by the usual classroom teachers according to the specified curriculum, whereas the 2 additional weekly lessons (45 min each) were taught mostly outdoors by PE teachers. In addition, 3‐5 short activity breaks (2‐5 min each) during academic lessons, comprising motor skill tasks such as jumping or balancing on 1 leg, power games, or co‐ordinative tasks, were introduced every day. The children received daily PA homework of about 10 min’ duration prepared by the PE teachers. This included aerobic, strength, or motor skill tasks such as brushing their teeth while standing on 1 leg, hopping up and down the stairs, rope jumping, or comparable activities. PA combination intervention vs control
Outcomes	Outcome measures Primary outcome: sum of 4 skinfolds, aerobic fitness, PA, quality of life Secondary outcomes: BMI, CV risk score (comprising all components of the metabolic syndrome including waist circumference) Process evaluation: NR
Implementation‐related factors	Theoretical basis: SEM Resources for intervention implementation: reported Who delivered the intervention: reported PROGRESS categories assessed at baseline: child: gender; parent: race/ethnicity, education PROGRESS categories analysed at outcome: NR Outcomes relating to harms/unintended effects: NR Intervention included strategies to address diversity or disadvantage: NR Economic evaluation: NR
Notes	ISRCTN15360785 Funding: this study was funded by the Swiss Federal Office of Sports (grant number SWI05‐013), the Swiss National Science Foundation (grant number PMPDB‐114401), and the Diabetes Foundation of the Region of Basel. The funding sources had no role in the design and conduct of the study or in the collection, management, analysis, and interpretation of the data. All assessors were trained in a pilot study 2 months before the main study. The level of adherence to the intervention outside school (PA homework) was insufficient, which is a limitation of this study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomly selected and assigned in a 4:3 ratio after stratification for grade; selected 28/190 consenting classes on the basis of a computer‐generated random number table that was in the hands of a person not involved in the study
Allocation concealment (selection bias)	Low risk	Randomly selected and assigned in a 4:3 ratio after stratification for grade; selected 28/190 consenting classes on the basis of a computer‐generated random number table that was in the hands of a person not involved in the study
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Assessors responsible for the measurements were blinded to the group allocation for all measurements except skinfold and waist circumference measures
Incomplete outcome data (attrition bias) All outcomes	High risk	36% vs 51% (intervention vs control) attrition at 3 years post intervention. Quote: "More obese children and those with a migrant background dropped out tried to account for this possible bias by adding a propensity score to our model (to adjust for differential participation) showing that our results remained the same despite adjustment for participation differences. This is especially true for zBMI, for which we had a participation bias in favour of initially leaner children being more prevalent in the intervention than in the control group"
Selective reporting (reporting bias)	Low risk	All pre‐specified outcomes have been reported
Other bias	Low risk	No additional threats to validity
Other bias‐ timing of recruitment of clusters	Low risk	Figure shows recruitment happened prior to randomisation