BACKGROUND:Stroboscopic visual training can force sensory reweighting to restore the original weights by increasing sensitivity to proprioceptive information,which may be an effective method to improve proprioception. OBJECTIVE:To determine the effects of balance training in three conditions,low frequency,high frequency and normal vision,on ankle proprioception in patients with chronic ankle instability. METHODS:Thirty-six patients with chronic ankle instability recruited from the students of Southwest Medical University were randomly assigned to a low-frequency vision training group,a high-frequency vision training group,and a normal vision training group,with 12 subjects in each group.Subjects in the three groups underwent progressive hop stabilization and balance training,in which the low-frequency vision training group and the high-frequency vision training group wore stroboscopic spectacles during the training,with a stroboscopic frequency of 1.75 and 5 Hz,respectively.The training in each group was performed three times a week for 4 consecutive weeks.Assessments,including ankle proprioception,ankle stability self-assessment and dynamic postural stability,were performed before training and within 1 week after the completion of training. RESULTS AND CONCLUSION:There was a significant main effect of time factor in ankle proprioception(P<0.05).Compared with the pre-training period,subjects in the low-frequency vision training group and the high-frequency vision training group showed significant improvement in ankle proprioception after 4 weeks of training(P<0.05);and subjects in the low-frequency vision training group showed a significant improvement in ankle proprioception compared with that of the normal vision training group after 4 weeks of training(P<0.05).There were significant main effects of time factor and group×time interaction in ankle proprioception(P<0.05).Compared with the pre-training period,the ankle stability self-assessment in all three groups was improved after 4 weeks of training(P<0.05).And the ankle stability self-assessment in high-frequency visual training group was higher than that in normal vision training group after 4 weeks of training(P<0.05).Compared with the pre-training period,subjects in the low-frequency vision training group and the high-frequency vision training group showed significant improvements in forward dynamic postural stability,posteromedial dynamic postural stability,and posterolateral dynamic postural stability after 4 weeks of training(P<0.05),while in the normal vision training group,forward dynamic postural stability and posterolateral dynamic postural stability were significantly improved after 4 weeks of training(P≤0.05).To conclude,balance training under stroboscopic visual conditioning improves proprioception,ankle stability self-assessment,and dynamic postural stability in patients with chronic ankle instability regardless of frequency.