Athletes and soldiers must both develop and maintain high levels of physical fitness for the physically demanding tasks they perform; however, the routine physical activity necessary to achieve and sustain fitness can result in training-related injuries. This article reviews data from a systematic injury control programme developed by the US Army. Injury control requires 5 major steps: (i) surveillance to determine the size of the injury problem; (ii) studies to determine causes and risk factors for these injuries; (iii) studies to ascertain whether proposed interventions actually reduce injuries; (iv) implementation of effective interventions; and (v) monitoring to see whether interventions retain their effectiveness. Medical surveillance data from the US Army indicate that unintentional (accidental) injuries cause about 50% of deaths, 50% of disabilities, 30% of hospitalisations and 40 to 60% of outpatient visits. Epidemiological surveys show that the cumulative incidence of injuries (requiring an outpatient visit) in the 8 weeks of US Army basic training is about 25% for men and 55% for women; incidence rates for operational infantry, special forces and ranger units are about 10 to 12 injuries/100 soldier-months. Of the limited-duty days accrued by trainees and infantry soldiers who were treated in outpatient clinics, 80 to 90% were the result of training-related injuries. US Army studies document a number of potentially modifiable risk factors for these injuries, which include high amounts of running, low levels of physical fitness, high and low levels of flexibility, sedentary lifestyle and tobacco use, amongst others. Studies directed at interventions showed that limiting running distance can reduce the risk for stress fractures, that the use of ankle braces can reduce the likelihood of ankle sprains during airborne operations and that the use of shock-absorbing insoles does not reduce stress fractures during training. The US Army continues to develop a comprehensive injury prevention programme encompassing surveillance, research, programme implementation and monitoring. The findings from this programme, and the general principles of injury control therein, have a wide application in civilian sports and exercise programmes.