The main aim of the project is to examine the fidelity (defined as how closely a set of procedures were implemented as they were supposed to have been) of an intervention aimed at enhancing young peoples' physical activity and well-being, via training of grass-root coaches of 10-14 year-old football players. 4 articles in international peer-review journals are planned. The objectives of the two first studies are to better understand the barriers and facilitators of implementing an "Empowering coaching" wo rkshop coming from another culture and relying on expert coach training. The other two studies utilize the RE-AIM framework (a set of criteria for designing and evaluating the impact of theoretically grounded health behaviour interventions) to determine t he reach, effectiveness, adoption, implementation and maintenance of the intervention at four levels: the coach educators, the club level, the grass-root coach and the player level. In particular, differences in fidelity and implementation of the interven tion between France and Norway will be studied. The French partner is Laboratoire Sport et Environnement social at the Université Joseph Fourier, and the Norwegian partner is Department of Health Promotion and Development at the University of Bergen. The Norwegian team has an expertise in health promotion and public health and the French team is implemented in the sport field. While both teams focus on well-being and the promotion of healthy behaviour, their complementariness rely on the interdisciplinar y mixing of the two research fields. This Aurora project is focused on the training of young researchers, principally PhD and post-doc students, especially with regard to methodological training in statistical and qualitative analysis using Nvivo and Mplu s software.