ObjectiveTo examine the association between physical activity-related injuries and participation in walking versus running.DesignNested case-control study.SettingCooper Clinic Preventive Medicine Center, Dallas, Texas.Participants5,327 men and women undergoing exams between 1987 and 1995 and completing follow-up health history questionnaires in 1990 or 1995. Participants were classified as those reporting regular participation in walking or jogging/running at baseline. Those reporting both or neither activity were excluded from the study (n = 1404). Cases (698 men, 169 women) were those reporting physical activity-related injuries requiring physician visits in the previous year on the follow-up questionnaire. Controls (2,358 men, 698 women) were randomly selected from the remaining population.Main Outcome MeasuresLogistic regression was used to examine the risk of injury in walkers versus runners and risk of injury by exercise dose while considering age, body mass index, previous injury, and strength training.ResultsThere was a significantly lower risk of injury for walkers compared with runners in young (<45 years old) (odds ratio [OR] = 0.75, 95% confidence interval [CI] = 0.58–0.97) and older (≥45 years) men (OR = 0.64, 95% CI = 0.49–0.82), and a nonsignificantly lower risk among young (OR = 0.73, 95% CI = 0.39–1.37) and older women (OR = 0.72, 95% CI = 0.38–1.35). There was no effect of greater amounts of walking on injuries for either gender; however, there was a higher injury risk associated with running 15–30 min/day (OR = 1.36, 95% CI = 1.07–1.73) and 30+ min/day (OR = 1.52, 95% CI = 1.14–2.04) compared with <15 min/day among men, but not among women.ConclusionsThis low risk of musculoskeletal injury suggests that participation in walking can be safely recommended as a way to improve health and fitness.