Context: Individuals with chronic ankle instability (CAI) rely more on visual information during postural control due to impaired proprioceptive function. The increased reliance on visual information may increase the risk of injury when their vision is limited during complex sports activities. Stroboscopic glasses may help elicit sensory reweighting during postural control. Therefore, we assumed that the glasses would induce and train CAI patients to reweight sensory information for the somatosensory system during dynamic balance training. Purpose: (1) to identify the effects of the 4-week dynamic balance training on the reliance of visual information during postural control in patients with CAI and (2) to compare the effects of the 4-week dynamic balance with and without stroboscopic glasses on postural control in patients with CAI. Methods: This study was a randomized controlled trial. Twenty-eight CAI patients were equally assigned to one of 2 groups: a strobe group (6 males and 8 females) or a control group (8 males and 6 females). The 4-week dynamic balance training consisted of multiple single-legged exercises. The strobe group wore stroboscopic glasses during the training, but the control group did not. The main outcome measures included the following: self-reported function measures, static postural control (center of posture (COP)-based measures), and dynamic postural control including the Dynamic Postural Stability Index (DPSI), and the Star Excursion Balance Test (SEBT). There were 3 visual conditions in the static postural control (eyes-open (EO), strobe vision (SV), and eyes-closed (EC)), and 2 conditions in the dynamic postural control (EO and SV). Two-way randomized block ANOVAs were used to assess changes in postural control in each group and condition by using pretest-posttest mean differences. Results: The strobe group showed a higher difference in COP velocity in medial-lateral direction (VelML) and vertical stability index (VSI) under the SV condition compared with the control group (p = .005 and .004, respectively). In addition, the strobe group had significant decreases in VelML, DPSI, and VSI at the posttest compared with the pretest (p = .0001, .01, and .005, respectively). Conclusion: The 4-week dynamic balance training with stroboscopic glasses appeared to be effective in improving postural control and altering visual reliance in patients with CAI.

Context: Chronic ankle instability (CAI) individuals experience residual symptoms including pain, swelling, ankle instability, etc. A small majority of CAI individuals report ankle pain during daily or physical activity. Despite the known negative effects of chronic pain on neuromuscular control, there is a paucity of research exploring the specific impact of chronic pain mechanisms on altered neuromuscular control in CAI individuals. Purpose: The purpose of this study was to identify the effects of pain levels on static and dynamic postural control and visual reliance in CAI individuals. Methods: A total of 60 participants were recruited, consisting of 20 CAI individuals with high pain, 20 CAI individuals with low pain, and 20 healthy controls. Participants performed static postural control with eyes open and closed, the star excursion balance test (SEBT), and single-leg hop stabilization. One-way ANOVA assessed differences in Romberg ratios, SEBT, dynamic postural stability index, and self-reported outcomes. Two-way ANOVA (3x2) was used to assess differences in static postural control across the three groups. Results: The high pain group showed decreased mediolateral (ML) direction of static postural stability in eyes closed and a higher Romberg ratio in ML direction compared to the low pain group. The high pain group showed decreased reach distance and increased dynamic postural control in vertical and dynamic postural stability index compared to the healthy control group and low pain group, respectively. Conclusions: The levels of chronic pain can have a significant impact on both static and dynamic postural control and visual reliance in CAI individuals. Therefore, fluctuating chronic pain levels may result in alterations in motor outcomes.