Relationship between the G Tolerance, Physical Performance, and Cardiac Force Index in Male Aircrew: A Prospective Observational Study

PURPOSE: Whether G tolerance is correlated physical performances and cardiac force index (CFI) in male aircrew. METHODS: One month before the high G training, military flight cadets provided demographic data and details about their exercise habits. They wore BioPatch™ HP devices to track cardiac data, including walking CFI (WCFI), and during the 100-m sprint tests. Jump performance was assessed on the training day by measuring peak power output, peak power output normalized to total body mass, the product of force and time at the moment of the jump, and vertical jump height. Relaxed G tolerance and straining G tolerance were evaluated using a gradual onset rate. Logistic regression was used to analyze the relationships between G tolerance, physical performance, and CFI. RESULTS: There were 53 male trainees classified in the low tolerance group and 29 ones in the high tolerance group. The finish time for the sprint in the high tolerance group averaged 14.1 ± 1.0 s, which was shorter than the 14.4 ± 1.1 s recorded for the low tolerance group. A higher WCFI (>0.15 vs ≤0.15) before the sprint was consistently associated with enhanced G tolerance performance, with an adjusted odds ratio (aOR) of 3.72 (95% confidence interval, 1.10-12.60). Conversely, the sprint completion time was negatively associated with G tolerance (adjusted odds ratio, 0.38; 95% confidence interval, 0.15-0.95). CONCLUSIONS: Our findings indicate that a higher WCFI and shorter sprint times prior to the high G training are positively correlated with the G tolerance. Aircrew training centers may integrate sprint and jump tests alongside cardiovascular monitoring to classify cadets into high or low G tolerance groups for further personalized training regimens.