Effect of a Balance Adjustment System on Postural Control in Patients with Chronic Ankle Instability.

Background/purpose: This study aimed to evaluate how a two-week program using the in-phase mode of a balance adjustment system (the BASYS) affected postural control in participants with chronic ankle instability (CAI). It was hypothesized that the in-phase mode on the BASYS would lead to improved postural control compared with training on a balance disc.

Study Design: Randomized control trial.

Methods: Twenty participants with CAI were recruited. The participants were divided into two intervention groups: the BASYS (n = 10) and Balance Disc (BD; cushion type, n = 10). All participants underwent six supervised training sessions over a two-week period. Static postural control during single leg standing with closed eyes was assessed for the CAI limb. We collected COP data while participants balanced on the BASYS. The test was performed for 30 sec, and the total trajectory length and 95% ellipse area were calculated. In the assessment of dynamic postural stability, Y-Balance tests-anterior, posteromedial, and posterolateral directions were measured on the CAI limb for all participants and normalized to the individual's leg length. Participants were recorded at three instances: pretraining (Pre), post-training 1 (Post1: after the first training), and post-training 2 (Post2: after the last training).

Results: There was an effect on time in the COP total trajectory length of the BASYS group, which was significantly decreased for Post 1 and Post 2 than for the Pre (p = 0.001, 0.0001). Group differences and time-by-group interactions were not observed for either of the Y-balance test reach distances.

Conclusions: The study's primary finding was that two weeks of intervention in the in-phase mode on the BASYS improved static postural control in participants with CAI.

Level Of Evidence: Level Ⅰ, randomized control trial.