Factors associated with concussion during combatives activities in a military training environment

Background: Military service members routinely participate in combatives training (boxing, judo, martial arts, and hand-to-hand combat) to acquire and maintain mission essential skills. Despite injury mitigation strategies, high concussion incidence rates of 20.8 concussions per 100 exposures while participating in combative sports have been reported. The purpose of this study was to identify factors potentially associated with greater odds of sustaining a concussion in these combative activities in a military training environment. Methods: A retrospective cohort study was conducted with participants enrolled at 4 military service academies participating in the concussion assessment, research, and education consortium from 2014 to 2020. Demographic information (site, varsity status, sport contact level, sex, concussion history, and headache history) and pre-injury baseline assessments (e.g., Balance Error Scoring System (BESS), Brief Symptom Inventory (BSI)) were collected at the time of enrollment. Univariate and multivariable logistic regression models were used to estimate the odds of sustaining a concussion while participating in combatives training during the follow-up period based on these pre-injury characteristics. Results: During the study period, 17,681 participants (25% female;19.11 ± 1.45 years (mean ± SD)) completed a baseline assessment and 484 (35% female;19.88 ± 1.43 years) sustained a concussion during a combatives training. Univariate logistic regression models revealed females (odds ratio (OR) = 1.71; p < 0.001; 95% confidence interval (95%CI): 1.41–2.07), participating in high contact varsity sports (OR = 0.52; p < 0.001; 95%CI: 0.38–0.71), BSI total score (OR = 1.03; p < 0.001; 95%CI: 1.01–1.04), BESS total score (OR = 1.02; p < 0.001; 95%CI: 1.02–1.04), and headache history (OR = 1.43; p < 0.001; 95%CI: 1.18–1.73) were associated with greater odds of sustaining a combatives-related concussion. Multivariable models yielded similar results after controlling for significant covariates. Conclusion: Females, higher BSI and BESS total scores at baseline, and participants with a history of headaches had greater odds of sustaining a combatives-related concussion during the follow-up period. Conversely, participants in high contact varsity sports had lower odds of sustaining a combatives-related concussion. These different variables should be taken into account when designing combatives training programs in a military setting.