Body Composition and Physical Performance in Military Personnel: A Systematic Review of Anthropometric Predictors and Operational Implications.

INTRODUCTION: Body composition and anthropometric characteristics may influence physical performance, operational readiness, and musculoskeletal injury risk in military personnel. However, the magnitude and specificity of these associations remain inconsistently described across military populations, operational settings, and assessment methods. This systematic review aimed to identify and analyze the main anthropometric and body composition factors associated with physical performance in military personnel and to discuss their operational implications. MATERIALS AND METHODS: This systematic review followed PRISMA 2020 recommendations and was registered in PROSPERO (CRD420261348930) before study selection. Searches were conducted in PubMed/MEDLINE, Web of Science, LILACS/BVS, Scopus, and Embase. Experimental and observational studies involving adult military personnel of either sex were considered eligible when they examined anthropometric or body composition variables in relation to physical performance, operational capacity, or musculoskeletal injury risk. Methodological quality was assessed using National Heart, Lung, and Blood Institute tools. A meta-analysis was not performed because of substantial heterogeneity in study designs, body composition measures, and performance outcomes. RESULTS: A total of 3,320 records were identified, and 17 studies were included in the final qualitative synthesis. Greater total lean mass and favorable segmental muscle distribution were generally associated with better strength, power, load carriage, and cardiorespiratory performance. In contrast, higher body fat percentage, elevated body mass index, visceral fat, and waist circumference were generally associated with poorer cardiorespiratory and functional performance and, in some studies, greater musculoskeletal injury risk. Across the included studies, direct body composition measures provided more meaningful performance-related information than body mass index alone. CONCLUSIONS: Body composition appears to be a relevant determinant of military physical readiness. Lower adiposity and greater lean mass tend to favor physical performance, whereas excess fat mass and elevated body mass index may impair physical efficiency and increase injury-related risk. Military settings should consider broader use of direct body composition assessment methods and evidence-based training strategies. Future research should improve methodological consistency, include more women, and further investigate operationally relevant performance outcomes.