Assess graduate-level understanding of the neurobiological (e.g., neurotransmitters, neuroplasticity, HPA‑axis, inflammation, BDNF) and psychosocial (e.g., self‑efficacy, social support, behavioral activation, stress buffering) mechanisms by which physical activity influences mental health in adults, including mediator/moderator concepts, dose–response considerations, measurement approaches, and implications for research and interventions.