Evidence for preventive strategies to lessen running injuries is needed as these occur in 40%-50% of runners on an annual basis. Many factors influence running injuries, but strong evidence for prevention only exists for training modification primarily by reducing weekly mileage. Two anatomical factors - cavus feet and leg length inequality - demonstrate a link to injury. Weak evidence suggests that orthotics may lessen risk of stress fracture, but no clear evidence proves they will reduce the risk of those athletes with leg length inequality or cavus feet. This article reviews other potential injury variables, including strength, biomechanics, stretching, warm-up, nutrition, psychological factors, and shoes. Additional research is needed to determine whether interventions to address any of these will help prevent running injury.