Grunseit et al. 2020, Reach and impact of parkrun, a scoping review

Scoping review of 15 studies on parkrun, the free weekly timed 5 km event running in more than 20 countries with over 4 million registrants. A consistent minority of registrants (roughly 15-25% across samples) were inactive or non-runners at sign-up. The review notes that the evidence is dominated by cross-sectional and uncontrolled before-after surveys of self-selected current participants, with little data on those who drop out, so reported benefits cannot establish causation. Moderate for the descriptive reach claims; the causal health claims are weak by the review’s own account.