Profiling injuries sustained following implementation of a progressive load carriage program in United States marine corps recruit training

Issue title: Special Section: Physical Employment Standards

Guest editors: Robin M. Orr, Gemma S. Milligan, Sam D. Blacker, Jace Drain, Tara Reilly, Etienne Chassé, Andrew Siddall, Stephen Foulis, Helen Kilding and Veronica Jamnik

Article type: Research Article

Authors: Kelly, Karen^{a; *} | Niederberger, Brenda^{a; b} | Givens, Andrea^{a; b} | Bernards, Jake^{a; b} | Orr, Robin^c

Affiliations: [a] Applied Translational Exercise and Metabolic Physiology Team, Warfighter Performance, San Diego, CA, USA | [b] Leidos, Inc., San Diego, CA, USA | [c] Tactical Research Unit, Bond University, Robina, QLD, Australia

Correspondence: [*] Address for correspondence: Karen Kelly, Applied Translational Exercise and Metabolic Physiology Team, Warfighter Performance, San Diego, CA, USA.Email: Karen.r.kelly8.civ@heatlh.mil.

Abstract: BACKGROUND:Load carriage tasks during United States Marine Corps (USMC) recruit training can cause injury. Load carriage conditioning, if optimized, can reduce injury risk. OBJECTIVE:To compare injuries sustained by USMC recruits following participation in either the Original Load Carriage (OLC) program or a Modified Load Carriage (MLC) program. METHODS:Retrospective musculoskeletal injury data were drawn from the USMC San Diego Sports Medicine injury database for recruits completing the OLC (n = 2,363) and MLC (n = 681) programs. Data were expressed as descriptive statistics and a population estimate of the OLC:MLC relative risk ratio (RR) was calculated. RESULTS:The proportion of injuries sustained in the MLC cohort (n = 268; 39% : OLC cohort, n = 1,372 : 58%) was lower, as was the RR (0.68, 95% CI 0.61– 0.75). The leading nature of injury for both cohorts was sprains and strains (OLC n = 396, 29%; MLC n = 66; 25%). Stress reactions were proportionally higher in MLC (n = 17, 6%; OLC n = 4, 0.3%), while stress fractures were proportionately lower (MLC n = 9, 3%; OLC n = 114, 8%). Overuse injuries were lower in MLC (– 7%). The knee, lower leg, ankle, and foot were the top four bodily sites of injuries and the Small Unit Leadership Evaluation (SULE), Crucible, overuse-nonspecific, running, and conditioning hikes were within the top five most common events causing injury. The prevalence rates of moderate severity injury were similar (MLC = 23%; OLC = 24%), although MLC presented both a higher proportion and prevalence of severe injuries (MLC = 6%; OLC = 3%, respectively). CONCLUSION: A periodized load carriage program concurrently increased exposure to load carriage hikes while reducing injuries both during the load carriage hikes and overall.

Keywords: Musculoskeletal injury, boot-camp, injury prevention, progressive overload, military training

DOI: 10.3233/WOR-230569

Journal: Work, vol. 77, no. 4, pp. 1391-1399, 2024