The correlation between postural control and upper limb position sense in people with chronic ankle instability

Background: Chronic ankle instability (CAI) is attributed to functional instability driven by insufficient proprioception. However, it is not clear whether the deficits are related to global impaired performance or to specific decrease in ankle motor-control. The aim of this study was to assess the correlation between lower limb postural control and upper limb position sense among people with CAI, in order to further explore the function of the central neural control in people with CAI. Methods: Fourteen participants (10 males, 4 females) with self-reported CAI and 14 age- and gender-matched, healthy controls participated in this study. Each participant completed single-limb stance postural control tests and shoulder position sense tests. The Overall Stability Index (OSI) was used as a measure of postural stability. The average of the absolute error score (AES) was calculated as a measure of shoulder position sense. Pearson correlations between the scores of the four body sites -lower limb postural stability (preferred/non-preferred), shoulder (preferred/non-preferred) were determined separately for each group. Results: In the control group, significant correlations were found between the OSI score of the right and left ankles (r = 0.887, p < 0.001), between the AES of the right and left shoulders (r = 0.656, p = 0.011), as well as between the OSI score and the AES of the non-preferred side (r = 0.649, p = 0.012). In the CAI group, significant correlation was found only between the OSI score at both ankles (r = 0.6, p = 0.002). Conclusions: Individuals with CAI demonstrated lower limb postural control and upper limb position sense similar to those shown in healthy controls. However, correlations between the lower and upper limbs were observed only in the healthy controls. Clinicians can use this information and employ activities that focus on coordinating the upper and lower extremities when designing neuromuscular control training programs for people with CAI.