Effect of pre-accession physical fitness on training injuries among US army recruits

OBJECTIVE: To evaluate the association of pre-accession physical fitness, as measured by a five-minute step test, with incidence of overuse injuries and outpatient healthcare utilization among male United States (US) Army recruits. PARTICIPANTS: US Army male trainees who met weight standards and took a pre-accession fitness test. METHODS: In this prospective cohort study, incidence and outpatient healthcare visits for overuse injuries during the first 90 days of military service were compared between recruits who failed the pre-accession step test with those who passed. RESULTS: The hazard rate ratio for injury among recruits who failed the fitness test compared to those who passed the test was 1.31 (95% C.I = 1.20-1.44). Among the subset of recruits with at least one medical encounter for an overuse injury, the utilization rate ratio for subjects who failed the fitness test versus those who passed was 1.15 (95% C.I = 1.09-1.22). Other factors associated with increased risk of injury or healthcare utilization include age, body mass index, and smoking history. CONCLUSIONS: Risk of injury and utilization were associated with fitness test results. These findings may have implications for military accession and training policy as well as for other physically demanding training programs such as police, fire fighters and athletes.