Association Between Ambulatory Physical Activity and Injuries During United States Army Basic Combat Training

Abstract

Background:Associations between physical activity and injuries have been previously examined using self-reports. The present investigation examined this association using objective measures of activity and injury.Methods:To quantify ambulatory activity, pedometers were worn daily by recruits in 10 Army Basic Combat Training companies during the 9-week training cycle. Injuries were obtained from a medical surveillance system, defined as traumatic or overuse events resulting in a medical care provider visit. A daily questionnaire documented whether or not recruits wore the pedometers and trained with their companies for the entire day.Results:Training companies were categorized by activity level into 3 groups with higher activity (HA, 17,948 ± 550 steps/day), 4 with moderate activity (MA, 16,346 ± 768 steps/day) and 3 with lower activity (LA, 14,772 ± 400 steps/day). Among men, the MA and HA groups were at 1.52 (95% confidence interval [95% CI] = 1.15−2.01) and 1.94 (95% CI = 1.46−2.61) times higher injury risk, respectively, compared with the LA group. Among women, the MA and HA groups were at 1.36 (95% CI = 1.07−1.73) and 1.53 (95% CI = 1.24−1.89) times higher injury risk, respectively, compared with low LA group. The relationships remained significant after considering physical characteristics and physical fitness.Conclusions:In consonance with previous self-report studies, higher physical activity was associated with higher injury risk.