Prevention of pelvic stress fractures in female army recruits.

In 1991-1992, a pelvic stress fracture incidence of 11.2% was recorded in a cohort of 143 female Australian Army recruits. An incidence of 0.1% was recorded in a cohort of male recruits trained in the 1992-1993 year using a nearly identical program. A number of preventive strategies were instituted in an attempt to reduce the high incidence of injury in female recruits. Route march speed was reduced from 7.5 to 5 km/h, running occurred on softer surfaces, individual step length was promoted instead of marching in step, march and run formations were more widely spaced, and interval-running training replaced traditional middle-distance runs. Pelvic stress fracture incidence decreased significantly to 0.6% in an immediately subsequent cohort of 161 female recruits (chi 2 = 15.12 for 1 df; p < 0.001). It is likely that the preventive strategies reduced bone strain by reducing the frequency and forces of impact during the training period.