Sex Is Not an Independent Predictor of Exercise-Induced Pain After Adjustment for Performance and Pain Sensitivity.

Introduction: Exercise-induced pain (EIP) is a transient pain phenomenon that emerges during physical exertion and resolves soon after exercise cessation. Despite being recognized as a performance-limiting variable in endurance sports, the mechanisms driving its interindividual variability remain poorly defined. We aimed to determine whether sex remains a significant predictor of EIP intensity after adjustment for performance and pain sensitivity. Materials and Methods: This cross-sectional study enrolled 122 recreational athletes (61 males and 61 females), including 48 trail runners and 74 hikers. Participants provided self-reported data on demographics and training habits. Performance was evaluated using both external and internal load metrics: external load was represented by activity duration and effort-adjusted speed, while internal load was assessed using the rating of perceived exertion (RPE). Maximum and average EIP was rated on a numeric rating scale and combined into a pain composite score (PCS). Pain threshold and tolerance were measured using the cold pressor test. Associations between variables and pain outcomes were analyzed using generalized linear models. Results: No significant differences were observed in maximum or average EIP intensity, pain threshold, or pain tolerance between male and female athletes. Sex was not a significant predictor of the PCS after adjusting for external and internal exercise load. Neither pain threshold nor tolerance significantly predicted PCS, and these associations did not vary by gender. Conclusion: In recreational endurance athletes, sex had no significant impact on EIP intensity when accounting for performance and pain sensitivity. These findings challenged traditional assumptions about sex-related pain differences.