When the Mind Gives Out Before the Body: How Psychological Traits Predict Sustained Performance Under Maximal...

Physical readiness is a critical component of military effectiveness, yet the psychological factors that drive performance under physical duress are not fully understood. Although the link between psychology and exercise behavior is well-established, less is known about how stable personality traits and motivational orientations directly impact maximal physiological output. This study aimed to investigate the association between the "Big Five" personality traits, motivational needs from Self-Determination Theory, and objectively measured aerobic capacity, anaerobic power, and muscular endurance in a military population. A secondary aim was to determine if motivation serves as a psychological pathway mediating the relationship between personality and performance.

This longitudinal study used a sample of 186 active duty U.S. Air Force and Space Force personnel, which involved baseline (pre-intervention) and post-intervention testing separated by a 12-week supervised training program. At baseline, participants completed the NEO Five-Factor Inventory (NEO-FFI) to assess personality and the Basic Psychological Needs in Exercise Scale (BPNES) to measure motivation. Subsequently, they underwent standardized physiological testing to determine VO2max, anaerobic power (Wingate), and muscular endurance. Associations were analyzed using simple linear regression, and mediation analyses were performed to test the indirect effects of personality on performance through motivation.

Personality traits were significantly associated with physical performance. Neuroticism demonstrated a consistent negative relationship with aerobic capacity, anaerobic power, and muscular endurance. In contrast, conscientiousness was positively associated with aerobic capacity and muscular endurance. Among motivational factors, only autonomy was a significant predictor, showing a positive association with both aerobic capacity and muscular endurance. Mediation analyses revealed that autonomy functioned as a significant pathway linking neuroticism to endurance performance; the negative effect of neuroticism on aerobic capacity and muscular endurance was nullified when accounting for autonomy.

This study provides compelling evidence that psychological characteristics are systematically associated with objective physical performance in a military cohort. The findings suggest that maximal effort is not purely a physiological event but is significantly influenced by an individual's psychological regulation of effort and discomfort. A key strength is the use of objective, gold-standard performance measures. However, the cross-sectional nature of the mediation analysis and the use of a convenience sample are limitations. These results have direct implications for military training, suggesting that fostering an autonomy-supportive environment may mitigate the negative impact of traits like neuroticism and enhance operational readiness. Future longitudinal research should explore interventions designed to cultivate psychological resilience to improve physical performance outcomes.