Demographic changes, Running Club North Races, 2006‒2026

Equinox Marathon Start, 2025. Photo: Todd Paris Abstract We review race participation for Running Club North races between 2006 and 2026, examining demographic changes across the period, and the post-pandemic recovery. Finisher records for 12 races from 2006 through 2026 (115,945 records) come from my races database, with the race-year as the unit of analysis. We fit hierarchical models in rstanarm: binomial models for the proportion of the field in each group, and negative binomial models for how many people of each group finished. The group models estimate an overall trend and a pandemic shift together, so the shift is determined independent of any trend already present. The participant models compare 2015–2019 with 2022–2026. Over twenty years the 60+ group rose (odds ×2.70, 95% credible interval 1.62–4.38) and the 40–49 group fell (×0.73, 0.53–0.96), as did the 50–59 group (×0.58, 0.35–0.92). The younger bands vary so much from race to race that their trends can’t be identified.…