Icaps (an intervention targeting middle school students focused on physical activity and sedentary behavior) is a study that involved 1,000 sixth-grade students from eight middle schools in the Bas-Rhin department. It was conducted over a four-year period. The goal was to encourage young people to engage in physical activity by influencing their knowledge and that of their social circle, while also facilitating access to the activities themselves. Each year, participants completed questionnaires on lifestyle habits and attitudes toward physical activity, supplemented by a medical examination. This intervention was officially recognized as effective by the WHO in 2009. After six years, the initial results of Icaps 2 indeed show beneficial effects that persist two years after the study ended. These effects are more pronounced among young people who were initially sedentary and among those from disadvantaged backgrounds. This brochure explains why it is important to promote physical activity among young people, how to do so, how to implement and expand an Icaps-type strategy, and the possible frameworks for its implementation. A practical guide co-authored by the Icaps team and Inpes is available for download on the Inpes website and/or can be ordered free of charge from the distribution service. The last page lists all useful links to resources and partners.