Effects of Chronic Swelling on Dynamic Balance in Chronic Ankle Instability

OBJECTIVES Chronic ankle instability (CAI) is associated with impaired dynamic postural control and reduced self-reported function. Although swelling is commonly reported in individuals with CAI, it remains unclear whether swelling contributes to additional balance deficits. Therefore, the purpose of this study was to examine dynamic postural control and self-reported function in individuals with CAI classified by swelling status.METHODS: Physically active young adults were assigned to 3 groups: CAI with swelling (CAI-S; n = 15), CAI without swelling (CAI-NS; n = 15), and healthy controls (CON; n = 15). Swelling status was assessed using tape measures. Dynamic postural control was evaluated using the Y-Balance Test (YBT) with normalized reach distances in the anterior (ANT), posteromedial (PM), and posterolateral (PL) directions. Self-reported function was assessed using the Foot and Ankle Ability Measure (FAAM-ADL and FAAM-Sport) and the Ankle Instability Instrument (AII). One-way ANOVA was used to examine group differences with post hoc comparisons and effect sizes (Cohen’s d).RESULTS The CAI-S group demonstrated a shorter ANT reach distance (61.68 ± 6.69%) than CON (70.66 ± 13.98%; <i>p</i> < 0.01), whereas CAI-NS (63.25 ± 6.28%) did not differ from CON (<i>p</i> = 0.07). In contrast, both CAI-S (PM: 106.16 ± 7.33%, PL: 100.91 ± 10.46%) and CAI-NS (PM: 108.23 ± 13.76%, PL: 101.38 ± 10.46%) exhibited shorter PM and PL reach distances compared with CON (PM: 117.53 ± 8.93%, PL: 114.09 ± 8.17%; all <i>p</i> < 0.01), with no differences between CAI groups. Both CAI groups reported worse self-reported outcomes than CON, including lower FAAM-ADL and FAAM-Sport scores and higher AII scores, with no differences between CAI subgroups.CONCLUSIONS Ankle swelling was associated with direction-specific impairments in dynamic balance, particularly in the ANT direction, whereas multidirectional balance deficits and reduced self-reported function appear to be common in CAI regardless of swelling status.