Gender differences in musculoskeletal injury rates: a function of symptom reporting?

Purpose: This study determined gender differences in voluntary reporting of lower extremity musculoskeletal injuries among U.S. Marine Corps (USMC) recruits, and it examined the association between these differences and the higher injury rates typically found among women trainees. Methods: Subjects were 176 male and 241 female enlisted USMC recruits who were followed prospectively through 11 wk (men) and 12 wk (women) of boot camp training. Reported injuries were measured by medical record reviews. Unreported injuries were determined by a questionnaire and a medical examination administered at the completion of training. Results: Among female recruits the most commonly reported injuries were patellofemoral syndrome (10.0% of subjects), ankle sprain (9.1%), and iliotibial band syndrome (5.8%); the most common unreported injuries were patellofemoral syndrome (2.1%), metatarsalgia(1.7%), and unspecified knee pain (1.7%). Among male recruits iliotibial band syndrome (4.0% of subjects), ankle sprain (2.8%), and Achilles tendinitis/bursitis (2.8%) were the most frequently reported injuries: shin splints (4.6%). iliotibial band syndrome (4.0%), and ankle sprain (2.8%) were the most common unreported diagnoses. Female recruits were more likely to have a reported injury than male recruits (44.0%) vs 25.6%, relative risk (RR) = 1.72, 95% confidence interval (CT) 1.29-2.30), but they were less Likely to have an unreported injury (11.6% vs 23.9% RR = 0.49, 95% CI 0.31-0.75). When both reported and unreported injuries were measured, total injury rates were high for both sexes (53.5% women, 45.5% men, RR = 1.18, 95% CI 0.96-1.44), but the difference between the rates was not statistically significant. Conclusions: Our results indicate that the higher injury rates often found in female military trainees may be explained by gender differences in symptom reporting.