OLS regression and marginal analysis results.

This study examines the association between club membership and marathon performance using a dataset of 206,653 London Marathon runners. Our results show a statistically significant association between club membership and marathon performance for both males and females which sees club membership potentially mitigating pace decline with age and resulting in substantial improvements in finishing times of up to 40 minutes. We implement a production function framework and align with three principles of economic organisation. The findings have relevance for marathon participants, coaches, and athletic associations as well as implications beyond athletics to other sports or cooperative activities.