Effects of sudden unexpected mechanical perturbation training aimed at the primary prevention of inversion ankle sprain on reactiveness of ankle movement and cortical activity in normal young adults.

[Purpose] To determine the effects of sudden unexpected mechanical perturbation training aimed at the primary prevention of inversion ankle sprain on the reactiveness of ankle eversion movement and cortical activity. [Participants and Methods] Sixty healthy participants were randomly allocated equally into 1) the sudden unexpected mechanical perturbation training group, 2) self-paced training group, or 3) control group. The first two groups performed each course of training 3 days per week for 4 weeks. During pre-training and post-training, the latency to peak amplitude on the surface electromyography of the peroneus longus and the time to reposition the plate back to its initial position under the right foot after sudden unexpected mechanical perturbation were measured. Functional near-infrared spectroscopy was used to measure the changes in the concentration of oxygenated hemoglobin. [Results] The latency to peak amplitude was significantly shorter in group 1 than in group 2; time to reposition the plate was the shortest among the 3 groups during post-training. The changes in the concentration of oxygenated hemoglobin were significantly increased in the supplementary motor and pre-motor areas during post-training than during pre-training in group 1. [Conclusion] Sudden unexpected mechanical perturbation training may facilitate the primary prevention of inversion ankle sprain via the positive effects on the reactiveness of ankle eversion movement and cortical activity.