Risk Factors for Stress Fractures in Military Recruits

Stress fractures occur most often in military recruits and athletes. A stress fracture is an overuse injury from repetitive loading of bone. It is brought on by vigorous weight-bearing activities.

Long-distance running, jogging, and marching are the most common causes of stress fractures. Stress fractures are also known as stress reactions, bone stress injuries, and fatigue fractures.

In this study, the medical records of over 150,000 soldiers from Finland were reviewed. All soldiers had been sent to the military hospital for an MRI because of pain caused by exercise. The most common pain pattern affected the pelvis, hip, thigh, or knee.

The goal of the study was to identify risk factors for stress fractures that could be identified by magnetic resonance imaging (MRI). Stress fractures diagnosed by x-ray were not included.

The results showed that stress fractures are most likely to occur in the first eight weeks of basic military training. This suggests the need to look more closely at the basic training program and possibly make some changes to reduce stress bone injuries.

Women are more likely to have stress fractures, especially sacral fractures. This is because of the wide pelvis and leg alignment in females. For both men and women, older age, poor physical fitness, and low muscle strength were the most common risk factors.

Age and gender can’t be changed. But fitness and weakness can be addressed early on in the training in order to prevent stress fractures. The authors suggest an injury-prevention program at the start of military training for all recruits, but especially for anyone with the risk factors identified.