Beyond ownership: the critical role of digital literacy in shaping the impact of digital access on physical activity

Background: The rapid proliferation of digital technology is often assumed to automatically foster healthier lifestyles, yet its impact on physical activity (PA) remains inconsistent and poorly understood. Moving beyond the simplistic focus on access, this study proposes and tests a theoretically grounded moderated mediation framework. It posits that digital literacy is the pivotal mechanism through which access influences PA, and that this mediation process is fundamentally moderated by the urban-rural divide, a key structural inequalities in China. Methods: = 18,251), we tested this framework using a counterfactual-based causal mediation analysis, complemented by instrumental variable and robustness checks. Results: The analysis reveals a stark urban-rural heterogeneity in mechanisms. For urban residents, digital literacy served as a significant partial mediator. In stark contrast, a consistent suppression effect was identified among rural residents: digital access exerted a significant negative direct effect on PA, which was counterbalanced by a stronger positive indirect effect through digital literacy. This indicates that in rural contexts, mere access may inadvertently displace physical activity, and its net benefit is contingent entirely on digital literacy. Conclusion: Our findings challenge the techno-optimistic narrative that equates access with positive outcomes. They necessitate a strategic policy pivot-from infrastructure expansion to an integrated approach that concurrently provides access, builds contextualized digital capability, and shapes healthier digital environments, with interventions tailored to the distinct mediation and suppression mechanisms observed across settings.