[en] Literature emphasizes the increasing prevalence of obesity. This phenomenon is related to growing health problems and to their cost for the society in terms of health expenses as well as lack of human well-being. Sedentary lifestyle is systematically pointed out as one of the determining factors at the origin of this situation. WHO (2001) underlined the need of a multifactorial action while Pate et al. (2006) highlighted the school’s central role. Within the school, it seems that the physical education (PE) teacher represents the corner stone of any process aiming to promote physical activity (PA) (USDHHS, 1996; Tappe & Burgeson, 2004). Nevertheless, when determining if PE teachers are ready to be the expected PA promoters, it appears that, in Wallonia (as it could be the case in other countries), several data show that the answer is not really positive. It seems that PE teachers need some support in order to make youths physically active, and adopting a healthy lifestyle. In fact, proposing traditional lessons focusing on sport would not be sufficient to reach these objectives. In this way, PE teacher educators should have two priorities: (1) to clarify the PE teachers’ representations of PA and (2) to identify and share strategies aiming to define their potential actions on the field. The presentation illustrated four approaches that were experimented at the University of Liege in pre- and in-service PE teacher education. The major goal of the speech was to involve the participants by stimulating reflexibility and content development. Four questions have been in the centre of the activity: (1) What is physical Activity? (2) What must be done, finally? (3) How to deal with arguments against practice? (4) What could do PE teachers to promote an active lifestyle? Each question was discussed through distinct approaches that could be used by the participants in their own practice.