Associate Professor George Mason University Warrenton, Virginia, United States
Purpose: Executive function under fatigue is critical for performance in military and high-stakes environments. This study examined how baseline cognitive and physical fitness (aerobic and anaerobic capacity, strength, power) predict executive function in a Rules of Engagement (RoE) task under fatigue. The RoE task integrates go/no-go components, working memory, and rule-switching, requiring rapid, context-dependent decisions while avoiding false alarms, simulating combat-relevant decision-making under stress. We investigated whether latent performance profiles derived from baseline cognitive and physical metrics classify individuals into distinct performance groups and whether aerobic fitness (2-mile run time, 2MR) interacts with profile classification to predict fatigued RoE performance. Methods: Thirty-three Army ROTC cadets (22 ± 4 years, 25 males) completed baseline cognitive and physical fitness assessments across two separate days during a structured performance testing week. On one day, cadets completed the Army Combat Fitness Test (ACFT). On a separate day, they completed baseline RoE and a 400m sprint, followed by two fatigue trials alternating 400m sprints with RoE assessments. Latent Profile Analysis (LPA) identified performance groups based on baseline cognitive and physical metrics. Hierarchical multiple regression (HMR) examined the effects of fitness and performance class on fatigued RoE false alarms. Results: LPA identified three performance classes: Class 1 (n=6): Poor cognitive, average physical abilities. Class 2 (n = 13): Good cognitive, poor physical abilities. Class 3 (n=14): Good cognitive, good physical abilities. Regression revealed that profile classification and its interaction with 2MR significantly predicted fatigued RoE performance (R² = 0.675, p < .001, f² = .542), with faster 2MR times associated with fewer false alarms (β = 1.08, p < .001). The effect of LPA class was also substantial (Class 3 vs. Class 1: MD = 0.258, p < .001, d = 2.14), confirming that higher cognitive and aerobic fitness resulted in superior executive function under fatigue. Conclusions: Profile classification was the strongest predictor of fatigued executive function, while aerobic fitness (2MR) further enhanced cognitive stability under fatigue. Practical Applications: These findings highlight why military and tactical training should prioritize both anaerobic power and aerobic endurance, as these components allow for faster physiological recovery and greater cognitive resources for executive function under fatigue. Higher fitness levels reduce relative task intensity, effectively buffering cognitive performance during physically demanding operations. Training programs integrating both cognitive and physical stressors may enhance decision-making in high-pressure environments, with aerobic endurance acting as a protective factor against cognitive decline under prolonged stress. Acknowledgements: NONE
