The final objective of this project is to investigate alternative intervention delivery modes, for an adolescent sample with subclinical depressive symptomatology, i.e., presenting with some depression symptoms but not at a level where major depressive disorder would be diagnosed. We aim to compare the effect of a completely mediated delivery approach for physical activity (i.e., no researcher contact) and a mediated intervention with face-to-face contact and fortnightly check-in telephone calls.