There is no doubt about the positive effects of physical activity on health and well-being on all populations, among which the 18-25 age group is considered vulnerable. European decisionmakers promote physical activity for all populations and encourage better monitoring of physical activity by harmonizing and specifying measures of its quantity. Some recent French reports combining the quantitative and qualitative aspect of physical activity allow to improve the understanding of the phenomenon of youth engagement and the offers of practices. By considering engagement in physical practices as a phenomenon emerging from a network of interacting factors linked to the characteristics of the individual, his living environment and his global environment, we will explore physical activity and its preferred formats by associating them with the individual and socio-cultural factors which favor it in different European countries. Through this approach we will identify the most promising factors in different cultures to promote it, the variables discriminating between active and sedentary populations and the main formats of practices. By multifactorial analyses, we will characterize typologies of active and inactive students according to the countries and will identify individuals representing at best the identified typologies for more in-depth interviews.