La pratique d’activité physique sportive ‘APS’ est un facteur de santé. Le sport est une forme d’activité physique ‘AP’ qui aide à atteindre les taux recommandés journaliers. Des plans de promotion des APS sont adoptés par les Etats Européens. Mais la pratique sportive recèle aussi des risques. Certaines blessures sportives génèrent des troubles de santé à long terme. La promotion de l’activité sportive est face à un paradoxe. Moyen d’être en bonne santé, elle comporte des risques liés aux modalités de pratique. Pour connaître l’ampleur de ces effets, des études épidémiologiques sont nécessaires. Elles aideront à déterminer les sous-groupes d’adolescents sportifs, et parmi eux, ceux qui sont à risque de blessure. En France, les études menées sont représentatives de la population nationale. En revanche, aucune n’a estimé la participation et les facteurs de risque en se focalisant sur la population adolescente. Aussi, la littérature internationale fait ressortir des variations de résultats en fonction de l’environnement de vie des participants. Nous avons donc réalisé des enquêtes épidémiologiques auprès de la population adolescente d’un département français spécifique : les Bouches-du-Rhône. Celui-ci se caractérise par un haut-niveau de pauvreté et d’inégalité. Par hypothèse, les résultats différent de ceux obtenus à l’échelon national. En plus des mesures objectives de participation et de blessures, nous avons questionné les adolescents sur les expériences qu’ils aimaient vivre dans leur sport préféré. Cette connaissance vise le développement d’initiatives de promotion de l’activité sportive adaptées aux goûts de cette population. (résumé non complet) / Participation in physical and sports activities ‘PSA’ is a health factor. Sport is a form of physical activity ‘PA’ that helps to reach the recommended amount of PA per day. PSA promotions plans are launched by European states. However, sport participation also involves significant risks. Some sports injuries provoke long-term health negative outcomes. Promotion of sport participation faces a paradox. As a mean of healthy state, it implies some risks linked to the modalities of participation. To know the extent of these effects, epidemiological studies are needed. They help to determine adolescents’ subgroups that play sports, and among them, those at greater risk of injury. In France, previous studies are representative of the national population. However, no study estimated sport participation and injury risks factors while focusing on adolescent. Moreover, international findings showed that variation of results exists as function of the life environment of participants. We performed epidemiological retrospectives studies among the adolescent population of a specific French locality: the Bouches-du-Rhône. This one is characterized by a high-level of poverty and inequalities. We made the hypothesis, that results differ compared to those obtained at the national level. In addition of objectives measures of participation and injuries, we asked adolescents about the experiences that they like to live in their favorite sport. This knowledge could be useful to the development of promotion initiatives that are adapted to the tastes of this population. (resume no complete)

No / Modification of high-risk movement strategies such as dynamic knee valgus is key to the reduction of anterior cruciate ligament (ACL) and patellofemoral joint (PFJ) injuries. Augmented feedback, which includes video and verbal feedback, could offer a quick, simple and effective alternative to training programs for altering high-risk movement patterns. It is not clear whether feedback can reduce dynamic knee valgus measured using frontal plane projection angle (FPPA). Methods Vertical ground reaction force (vGRF), two-dimensional FPPA of the knee, contact time and jump height of 20 recreationally active university students were measured during a drop jump task pre- and post- an augmented feedback intervention. A control group of eight recreationally active university students were also studied at baseline and repeat test. Results There was a significant reduction in vGRF (p = 0.033), FPPA (p < 0.001) and jump height (p < 0.001) and an increase in contact time (p < 0.001) post feedback in the intervention group. No changes were evident in the control group. Conclusion Augmented feedback leads to significant decreases in vGRF, FPPA and contact time which may help to reduce ACL and PFJ injury risk. However, these changes may result in decreased performance. Clinical relevance Augmented feedback reduces dynamic knee valgus, as measured via FPPA, and forces experienced during the drop jump task and therefore could be used as a tool for helping decrease ACL and PFJ injury risk prior to, or as part of, the implementation of injury prevention training programs.