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.