Evaluation of Single-leg Balance during Landing from 20- and 40-centimeter Heights in Individuals with and without Chronic Ankle Instability

Objective This study aimed to assess balance performance using kinematic measures of the center of pressure during single-leg landings from two different heights in individuals with chronic ankle instability (CAI), and to compare the findings with those from healthy individuals.Methods A total of 34 male participants aged 20 to 40 years (17 with CAI and 17 healthy controls) were recruited.Participants performed single-leg landings from heights of 20 and 40 centimeters onto a Kistler force plate, followed by maintaining a single-leg standing posture for 10 seconds.The measured variables included path length, sway amplitude, mean radial displacement, and sway area of the center of pressure (COP).Multivariate analysis of variance (MANOVA) was used for betweengroup comparisons, and repeated-measures ANOVA was applied for within-group analyses.Results Individuals with CAI demonstrated significantly greater COP path length in the frontal plane during landings from both heights compared to the healthy group.Additionally, increasing the landing height was associated with significantly greater path length and sway amplitude in the sagittal plane, mean radial displacement, and COP sway area (p < 0.05). ConclusionThe findings suggest that individuals with chronic ankle instability exhibit impaired balance, particularly in the frontal plane, during single-leg landings.Therefore, rehabilitation programs should focus on improving balance and stabilizing COP fluctuations by targeting the muscles involved in postural control.These results may inform therapeutic strategies and contribute to re-injury prevention in this population.