Purpose This prospective cohort study examined injuries and injury risk factors in 660 British Army infantry soldiers during a predeployment training cycle.

Methods Soldiers completed a questionnaire concerning physical characteristics, occupational factors, lifestyle characteristics (including physical training time) and previous injury. Direct measurements included height, body mass, sit-ups, push-ups and run time. Electronic medical records were screened for injuries over a 1-year period before operational deployment. Backward-stepping Cox regression calculated HR and 95% CI to quantify independent injury risk factors.

Results One or more injuries were experienced by 58.5% of soldiers. The new injury diagnosis rate was 88 injuries/100 person-years. Most injuries involved the lower body (71%), especially the lower back (14%), knee (19%) and ankle (15%). Activities associated with injury included sports (22%), physical training (30%) and military training/work (26%). Traumatic injuries accounted for 83% of all injury diagnoses. Independent risk factors for any injury were younger age (17–19 years (HR 1.0), 20–24 years (HR 0.71, 95% CI 0.55 to 0.93), 25–29 years (HR 0.89, 95% CI 0.66 to 1.19) and 30–43 years (HR 0.41, 95% CI 0.27 to 0.63), previous lower limb injury (yes/no HR 1.49, 95% CI 1.19 to 1.87) and previous lower back injury (yes/no HR 1.30, 95% CI 1.03 to 1.63).

Conclusion British infantry injury rates were lower than those reported for US infantry (range 101–223 injuries/100 soldier-years), and younger age and previous injury were identified as independent risk factors. Future efforts should target reducing the incidence of traumatic injuries, especially those related to physical training and/or sports.