Physically active children and adolescents are at reduced risk of developing risk factors for cardiovascular disease,1 and they are likely to have enhanced mental and emotional wellbeing.2 However, as with other developed countries, in the United Kingdom, three out of 10 boys and four out of 10 girls are estimated not to take the recommended 60 minutes each day of moderate to vigorous intensity physical activity.3 This is important, because in 2003, 28% of children in the UK were estimated to be overweight or obese.4

In this week's BMJ, Van Sluijs and colleagues report a systematic review of interventions to promote physical activity in children and adolescents.5 The review found weak or inconclusive evidence for the effectiveness of strategies to promote children's physical activity. It confirmed lessons from tobacco control6—that at least in adolescents the most effective interventions have many components and are undertaken in multiple settings (school, home, and community).

Randomised controlled trials that focus mainly on education are not sufficient to change behaviour and sustain such changes. This is irrespective of whether interventions target children, adolescents, or parents; low or high socioeconomic groups; or whether they are conducted …