(25) SEX DIFFERENCES IN ROTC ACFT PERFORMANCE: EXPLORING NORMALIZATION METHODS

Introduction:  Accurate assessment of physical fitness is critical in military contexts, where peak performance is essential for operational readiness. Recently implemented, the Army Combat Fitness Test (ACFT) has replaced the longstanding fitness assessment in the US Army. For active-duty soldiers, failure on the ACFT may result in punitive measures, while higher scores can be advantageous for promotion. Moreover, ACFT performance often informs subsequent exercise programming aimed at enhancing physical fitness and future ACFT performance. The ACFT now includes scoring standards per sex and age group, ensuring more fair and equitable evaluation; however, to guide exercise program development understanding sex differences in ACFT performance due to physiological differences between males and females is needed. In strength and conditioning settings various normalization methods are commonly used to interpret performances in absolute and relative to body composition (BC) measures. 

Purpose:  To assess the effects of normalization approaches on sex differences in ACFT performance among US Army Reserve Officers’ Training Corps (ROTC) cadets. 

Methods:  A total of 73 male (age=21.5yr±3.8, mass=79.7kg±13.1, BF%=18.6±5.6) and 24 female (age=19.5yr±1.3, mass=63.5kg±8.6, BF%=25.1±4.8) ROTC cadets participated. Body fat % (BF%) was collected using a handheld bioimpedance device. The ACFT consists of a 3 Repetition Maximum Deadlift (MDL), Standing Power Throw (SPT), Hand-Release Push-up (HRP), Sprint-Drag-Carry (SDC), Plank (PLK), and 2 Mile Run (2MR). Student’s t-test was computed for each ACFT event between sexes when normalized to total mass, fat-free mass (FFM), FFM to fat mass ratio (FFM:FM), and FFM index (FFMI). The p-value was set to 0.002 after Bonferroni correction to 30 comparisons. 

Results:  Without normalization (figure 1), large differences (p< 0.002) existed between sexes on MDL, SPT, SDC, HRP, and 2MR with the PLK the only event with no sex differences (p=0.358). When normalized to FFM:FM there are no sex differences for MDL (p=0.373) or SPT (p=0.168). Sex differences remain across all normalization methods for both SDC and 2MR (p< 0.002). All normalization methods reduce differences in HRP [total mass (p=0.984), FFMI (p=0.239), FFM (p=0.234), and FFM:FM (p=0.175)]. Sex differences increase when PLK is normalized to FFM:FM (p< 0.002, d=-0.82) and FFM (p=0.004, d=-0.70). 

Conclusions:  The findings highlight sex differences in absolute performance on all ACFT events, except for PLK, among ROTC cadets, with males generally outperforming females. However, when normalized, particularly when adjusted to FFM:FM, differences lessen for MDL, SPT, and HRP. PRACTICAL APPLICATIONS: When analyzing disparities in ACFT performance between sexes, it's important to choose normalization methods that factor in BC variables. Regardless of sex, understanding the impact of BC on ACFT performance can aid designing exercise programs and monitoring their effectiveness.

Acknowledgements: None