Prevention of ankle sprain, the most common sporting injury, is only possible once risk factors have been identified. Voluntary strength, proprioception, postural sway, and range of motion are possible risk factors. A systematic review was carried out to investigate these possibilities. Eligible studies were those with longitudinal design investigating ankle sprain in subjects aged > or = 15 years. The studies had to have measured range of motion, voluntary strength, proprioception, or postural sway before monitoring incidence of lateral ankle sprain. Dorsiflexion range strongly predicted risk of ankle sprain. Postural sway and possibly proprioception were also predictors. Therefore the preliminary evidence suggests that people with reduced ankle dorsiflexion range may be at increased risk of ankle sprain.