The Ability to Endure

: Mental Toughness in Elite Endurance Sport

Abstract

This thesis examined the role of mental toughness (MT) in elite endurance sport by integrating physiological, psychological, and experiential evidence across three linked studies involving professional, elite level athletes. Although MT is frequently positioned as a key determinant of performance under pressure, its independent contribution to endurance performance remains equivocal. Two quantitative studies were conducted with elite male sailors (n = 12) and elite male cyclists (n = 16), employing both open-loop (time-to-exhaustion) and closed-loop (self-paced time trial) endurance protocols. Across these testing protocols, self-reported MT demonstrated weak or non-significant direct associations with performance outcomes, including time-to-exhaustion and average power output. In contrast, MT was associated with selected physiological markers, including exercise economy, gross mechanical efficiency, and blood lactate concentration, suggesting that MT may influence how athletes regulate effort and tolerate physiological strain rather than directly enhancing performance. To contextualise these findings, a third qualitative study was conducted with five super-elite endurance athletes from multiple disciplines, using reflexive thematic analysis to explore lived experiences of MT in high-performance contexts. Three interrelated themes were identified: mentorship, self-organisation, and self-belief. These findings indicated that MT is not a fixed trait, but a developmental and context-sensitive resource shaped by training environments, social relationships, and exposure to challenge. Collectively, these results characterise MT as an interactive construct that may buffer or moderate the impact of physiological stress, supporting performance regulation under pressure rather than acting as a standalone predictor of endurance success.
This thesis advances theoretical understanding by positioning MT as a psychological capacity whose influence in elite endurance sport appears indirect, context-sensitive, and contingent on physiological preparation and environmental support. Rather than functioning as a standalone predictor of endurance performance, MT may support how athletes regulate effort, sustain goal-directed behaviour, and remain effective under conditions of fatigue, discomfort, and competitive pressure. Practically, the evidence indicates that MT development in elite sport is likely to be most effective when embedded within structured physiological training, mentorship, and psychologically informed performance environments.
Keywords: elite athlete, endurance performance, exercise physiology, mental toughness, pain tolerance, performance regulation

Date of Award	29 Jun 2026
Original language	English
Awarding Institution	University of Portsmouth
Supervisor	Mike Tipton (Supervisor), Daniel Brown (Supervisor) & Jo Corbett (Supervisor)