Relationships Between Balance And Self-reported Function In Civilians And Military Service Memberswith Chronic Ankle Instability

PURPOSE: Investigate within-group relationships between static balance, dynamic balance, and self-reported function in civilians and military service members with chronic ankle instability (CAI). METHODS: 82 adults with CAI (age = 25.7 ± 7.3 years; 35 females, 53 civilians) participated. Self-reported function was assessed with the Foot and Ankle Disability Index (FADI) Sport scale. Single limb static balance was assessed using a force plate in eyes closed conditions for three 10-second trials. The anterior-posterior (AP) and medial-lateral (ML) components of center of pressure were used to calculate mean and standard deviation time-to-boundary measures. Dynamic balance was assessed with an inertial measurement unit placed at L4/5 during a forward jump hop-to-stabilization task. Dynamic postural stability index (DPSI) values were calculated as the root mean square of both accelerations (Acc) and angular velocities (Gyro) respectively in the AP, ML, and Vertical directions and combined for resultant magnitudes. Pearson correlation coefficients were calculated between measures of static balance, dynamic balance, and self-reported function in each group. RESULTS: The average FADI Sport scores were 76.6 ± 14.4% for civilians and 63.6 ± 16.9% for service members. In both civilians and service members there were no significant correlations between FADI Sport scores and any balance measures (see Table). Both cohorts showed strong correlations within static balance measures, though only the civilian cohort showed a significant correlation between dynamic balance resultant measures (r = 0.47, p < .001). Notably, there were no significant correlations between measures of static and dynamic balance in either cohort. CONCLUSION: Measures of static and dynamic balance provide distinct information from self-reported function in both civilians and service members with CAI.Supported by the Congressionally Directed Medical Research Programs, grant W81XWH-20-2-0035. The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S. Government.