Exploring the Importance of Motor Competence for Behavioral and Health Outcomes in Youth.

In this study, we investigated the relationship between motor competence (MC) and behavioral and health outcomes in youth through its relationship to physical activity (PA) and body composition (in terms of body fat). To date, it is unclear whether these variables reciprocally influence each other over time. We assessed whether and how MC, PA and body composition influence each other across adolescence. In a longitudinal study with 14 months of follow-up, we recruited 166 adolescents aged 12-13 years. We recorded participants' self-reported PA and body fat percentage and assessed their MC using the Körperkoordinationstest für Kinder (KTK). We used linear mixed models and mediation analyses with crude and adjusted (age, sex, time point) models to examine associations among the selected variables across time. MC showed a bidirectional relationship with both PA (p < .001) and body fat (p < .001) in both crude and adjusted models. In addition, MC was a potential mediator (Sobel test = -3.18, p < .001) in the relation between body fat (as predictor) and PA (as outcome) in crude models, but no mediating effect was found in adjusted models. Thus, this study provided longitudinal evidence that MC and PA, as well as MC and body composition, can reciprocally influence each other across adolescence. We recommend the development of MC as a crucial strategy to increase PA engagement and to prevent obesity in youth.