Why is the incidence of stress fractures in military combat training greater for women than for men?
Stress fracture rates among female military trainees during basic training are more than twice those reported for males. This greater incidence appears to be due in part to the initial entry level of fitness of the recruits and specifically the ability of bone to withstand the sudden large increase in physical loading. Some studies that controlled for aerobic fitness were unable to demonstrate a difference in the incidence of injury between males and females when individuals of the same fitness level were compared. Factors such as increased stride length (shorter women having the same stride length as tall men in “co-ed” marching situations) and variations in specific exercise activities (different loading force during drop-knee push-ups) may contribute to the different site distribution of stress fractures in military women compared with men. When training regimens are imposed to deliver the necessary level of physical fitness to meet standards, the resultant stress on the less physic
