Objective: To determine whether a single high velocity, low amplitude thrust manipulation to the talocrural joint altered ankle range of motion.Design: A randomized, controlled and blinded study. Subjects: Asymptomatic male and female volunteers (N=41).Methods: Subjects were randomly assigned into either an experimental group (N=20) or a control group (N=21). Both ankles of subjects in the experimental group were manipulated using a single high velocity, low amplitude thrust to the talocrural joint. Pre and post measurements of passive dorsiflexion range of motion were collected.Results: No significant changes in dorsiflexion range of motion were detected between manipulated ankles and controls. A significantly greater pre-test dorsiflexion range of motion existed in those ankles where manipulation produced an audible cavitation. Conclusion:Manipulation of the ankle does not increase dorsiflexion range of motion in asymptomatic subjects. Ankles that displayed a greater pre-test range of dorsiflexion were more likely to cavitate, raising the possibility that ligament laxity may be associated with the tendency for ankles to cavitate.