The Army Combat Fitness Test (ACFT) is a newly developed test assessing U.S. Army soldiers\u27 combat readiness. Body composition characteristics vary between soldiers and could affect performance outcomes. The purpose of this cross-sectional study is to determine whether fat-mass and fat-free-mass can predict performance outcomes of the ACFT in ROTC cadets. Methods: ROTC cadets (31 males, 21 females; aged 20.5 ± 2.2 years) completed the 6-event ACFT (3-repetition maximum trap-bar deadlift [MDL], standing power toss [SPT], hand-release pushups [HRPU], sprint-drag-carry shuttle run [SDC], plank [PLK], and 2-mile run [2MR]). The cadets were invited into the laboratory for measurements of anthropometrics (height, weight, and body mass index [BMI]) and body composition analysis via the air displacement plethysmograph (body fat mass [BFM], fat-free mass [FFM]). The ability of body composition to predict ACFT performance was determined with a linear regression model. Significance was set at p \u3c 0.05. Results: BFM was significantly and negatively correlated to SDC (r = -.383, p = .005), PLK (r = -.567, p \u3c .001), 2MR (r = -.577, p \u3c .001), HRP (r = -.501, p \u3c .001) and overall ACFT score (r = -.574, p = .001) except 3DL (r = .199, p = .154) and SPT (r = -.193, p = .166). FFM was significantly correlated to SDC (r = .411, p = .001), PLK (r = .249, p = .047), 3DL (r = .266, p = .034), SPT (r = .458, p = .001), and overall ACFT score (r = .364, p = .003) except 2MR (r = .137, p \u3c .279) HRP (r = .126, p = .322). BFM significantly explained 33% (p = .001) of the variance on the total ACFT scores with a beta coefficient -4.632. Conclusion: Body composition measurements of BFM and FFM are predictors of the ACFT total score. These data show that both BFM and FFM are important metrics for assessing a soldier’s combat readiness. For every 1% increase in body fat, ACFT scores decreased by 4 points. For every 1kg increase in FFM, ACFT score increased by 1.5 points
