Factors Associated with Stress Fractures in Military Recruits

A study of 101 military recruits in basic training was performed to identify factors which may predispose to stress fractures. The majority of soldiers with stress fractures developed the first symptoms within the first three weeks of training. Of the subjects with fractures, 66% directly related the injury to the new routine of marching and running. It is well known that a new exercise routine which applies stress to bone leads to a remodeling phase to strengthen the bone. Unfortunately during the early period of remodeling excessive resorption temporarily decreases the ability of bone to withstand force. This process is more marked during the second to third week after the beginning of the new exercise routine. Modification of basic training to accommodate this temporary bone weakness could decrease the frequency of stress fractures.