Haerens 2006.

Study characteristics
Methods	Study design: cluster‐RCT
Participants	School inclusion criteria: random sample of 15 schools out of the 65 schools with technical and vocational education in West Flanders (Belgium) School exclusion criteria: — Student inclusion criteria: pupils in Grades 7 and 8 Student exclusion criteria: — Setting: school, urban Age group: adolescents Gender distribution: females and males Country/Countries where trial was performed: Belgium
Interventions	Intervention 1: PA and nutrition intervention. PA intervention focused on increasing levels of MVPA to at least 60 minutes/d. Schools received an intervention box with sports materials such as ropes, balls, and beach ball sets and were encouraged to create more non‐competitive opportunities for students to be physically active during breaks, at noon, or during after‐school hours, and to vary content of PAs offered. Children received a physical fitness test at the beginning of the second intervention year, where all children had to cycle for 10 minutes on a computerised cycle ergometer, then were given information on their fitness level and possible ways to improve it. The computer‐tailored portion of the intervention was completed once each school year during 1 class hour. Children completed PA questions on a computer screen, which was immediately followed by tailored feedback on the screen (e.g. normative feedback regarding activity levels, PA recommendations). The nutrition intervention focused on 3 behavioural changes: increasing fruit consumption 2+ pieces/d; reducing soft drink consumption and increasing water consumption; and reducing fat intake Schools were asked to sell fruit at very low prices or for free at least once/week, to offer fruit for dessert at lunch, and to offer free water via drinking fountains Intervention 2: PA and nutrition intervention (same as Intervention 1 group) plus parental involvement. Schools invited parents for an interactive meeting on healthy food, PA, and the relationship with overweight and health. 3 times/y, information on healthy food and PA was published in school papers and newsletters for parents, and parents received a free CD with the adult computer‐tailored intervention for fat intake and PA (same as the children's computer‐tailored intervention) for use at home and were asked to discuss results with their child and to give their child support to create a healthier lifestyle Comparator: no PA and nutrition intervention Duration of intervention: 2 years Duration of follow‐up: 2 years Number of schools: 15 Theoretical framework: trans theoretical model
Outcomes	PA duration Sedentary time BMI
Study registration	—
Publication details	Language of publication: English Funding: non‐commercial funding (Policy Research Centre Sport, Physical Activity and Health, funded by the Flemish Government) Publication status: peer‐reviewed journal
Stated aim for study	"The purpose of this study was to evaluate the 2‐year effects of an intervention targeting PA and healthy eating in middle schools"
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: randomisation process not reported
Allocation concealment (selection bias)	Low risk	Comment: all participants were allocated at a single point in time following recruitment, so at time of recruitment, allocation was not known
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: no information given; likely not done
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: no information given; likely not done
Incomplete outcome data (attrition bias) Anthropometrics, Fitness	High risk	Comment: incomplete outcome data; not adequately addressed
Selective reporting (reporting bias)	Unclear risk	Comment: no protocol published; cannot assess
Cluster RCT ‐ Recruitment bias	Unclear risk	Comment: unclear whether students were enrolled before randomisation
Cluster RCT ‐ Baseline imbalance	Unclear risk	Comment: baseline characteristics not described
Cluster RCT ‐ Loss of clusters	High risk	Comment: 704 participants lost to follow‐up; differences between those who dropped out and those who stayed in
Cluster RCT ‐ Incorrect analysis	Low risk	Comment: clustering accounted for in analysis