This article investigates the associations between fundamental motor skills (FMS), health-related fitness (HRF) and physical activity (PA) during middle childhood and examines whether HRF serves as a mediator in these pathways. The behavioral mechanism (e.g., maintaining appropriate levels of HRF) provides meaningful insights to understand the obesity trajectory during middle childhood.

Article tests a hypothesized path model of Theory of Planned Behavior (TPB) variables (i.e., attitude toward behavior, subjective norm, perceived behavioral control, and intention) with physical activity (PA) and depressive symptoms. The findings support the theoretical tenets of TPB and provide empirical evidence of the psychosocial mechanism of PA and depressive symptoms in Chinese adolescents. It suggests that building PA intervention strategies while considering the TPB framework may promote adolescents’ physical and mental health.