Sleep quality and military training injury during basic combat training: a prospective cohort study of Chinese male recruits

Objective To examine the association between sleep quality and military training injury (MTI) in recruits during basic combat training (BCT). Methods Participants were new recruits undergoing 12-week military BCT in China. Sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI) . Participants were classified into two groups based on their sleep quality (group 1, good sleep, PSQI score <7; group 2, poor sleep, PSQI score >= 7) at the start of BCT. Logistic regression analysis was conducted to test whether baseline PSQI score was associated with MTI incidence during BCT. Results A total of 563 participants were included. The incidence of MTI was significantly lower in group 1 (48/203, 23.6%) than in group 2 (150/360, 41.7%) (p<0.001). Logistic regression analysis showed that the odds of MTI were 2.307 times higher in group 2 than in group 1 without adjusting for confounders: OR=2.307, p<0.001. When the model was adjusted for age, ethnicity, educational level and family income (OR=2.285) or for the previous confounders plus body mass index (OR=2.377), the results were similar (both p<0.001). Analysis of the types of initial MTI showed that group 2 had about 2.1 times higher odds of soft tissue injury than group 1 (p<0.001 in all the three models). Conclusion Sleep quality before BCT influences the incidence of MTI, especially of soft tissue injury.