Effects of dual-task paradigm on the injury potential during landing among individuals with chronic ankle instability

Purpose Chronic ankle instability (CAI) causes maladaptive neuroplastic changes in the central nervous system, which may lead to high injury potential under dual-task conditions. This study aims to explore the effects of dual-task paradigm on the injury potential during landing among individuals with CAI.Methods Twenty participants with CAI (4 female and 16 male, 12 were affected with their right limbs and 8 were affected with their left limbs, 20.4 +/- 1.7 years, 176.9 +/- 5.0 cm, and 72.0 +/- 11.1 kg) and eighteen without CAI (6 female and 12 male, 20.2 +/- 1.5 years, 173.5 +/- 7.0 cm, and 70.3 +/- 10.8 kg) were recruited. They drop-landed on a trap-door device, with their affected or matched limbs on a flippable platform, under single- (drop-landing only) and dual-task (drop-landing while subtracting of serial threes) conditions. A twelve-camera motion capture system was used to capture the kinematic data. Two-way ANOVA with mixed design (CAI vs non-CAI groups by single-vs dual-task conditions) was used to analyze the data.Results Significant group-by-condition interactions were detected in the ankle inversion angle (P = 0.040, eta 2 p = 0.012) and ankle inversion angular velocity (P = 0.038, eta 2 p = 0.114). Both indicators decreased among individuals without CAI from single-to dual-task conditions, while remained unchanged among those with CAI; and they were higher among individuals with CAI under both single- and dual-task conditions, compared to those without CAI.Conclusion Individuals with CAI have a reduced ability to limit ankle inversion compared to those without CAI. Under dual-task conditions, individuals without CAI limited their ankle inversion, while those with CAI did not. Drop-landing, especially under dual-task conditions, poses a high risk of excessive ankle inversion for individuals with CAI.