Relationships between mental toughness, perceived stress and cortisol in novice marathoners

Abstract

Marathon performance depends on physical and psychological preparation. Although mental toughness (MT) can facilitate endurance performance, its relationship with physiological stress and training behaviors during marathon training remains unclear. Thus, this study examined relationships between MT, stress, and performance in novice marathoners.Participants (N=28; 15F) provided saliva samples and completed the Mental Toughness Index (MTI) and Perceived Stress Scale (PSS) three times (baseline, midpoint, and morning of the marathon). Training behaviors (minutes running, days running) were recorded throughout training, and aerobic measures were assessed via 2-mile time trials and VO2max. Mental skills training (MST; e.g., positive self-talk, imagery, attentional focus) took place via online lectures and was practiced during group runs. Mixed models examined relationships between variables across time, while regression models assessed predictors of marathon performance and injury (i.e., injured, not injured) risk factors. MT (p=.31) and PSS (p=.97) remained stable throughout training. Cortisol showed an inverted U-shaped pattern with a significant decrease from midpoint to marathon morning (p = .03). MT was significantly and negatively related to perceived stress (β=-.67, p=.001). Time running also positively correlated with MT across all time points (r = .46-.56, p =.025). There were no significant relationships that emerged between MT and aerobic fitness measures or perceived stress and marathon performance (p=.126). The MT-cortisol relationships displayed a pattern shift from negative at baseline and midpoint to positive at marathon morning, though none reached statistical significance. Neither MT nor cortisol significantly predicted injury. Results indicate structured MST can be integrated into marathon training, with MT showing adaptive relationships with psychological and behavioral outcomes. Greater MT was associated with lower perceived life stress and more time training. While we cannot assume causality, it is plausible that developing MT through targeted MST may enhance training adherence and duration. These findings have practical implications for practitioners working with novice marathoners, indicating that incorporating structured MST alongside physical preparation could help optimize training engagement and psychological readiness.