Impact of motor fatigue on spatiotemporal parameters of gait under single-and dual-task conditions in individuals with chronic ankle instability and copers.

Introduction: Chronic ankle instability (CAI) is associated with altered gait mechanics and cognitive-motor deficits, while some individuals with a history of ankle sprain recover successfully as copers. Dual-tasking and fatigue represent common real-world challenges, but their combined effects on gait in CAI compared with copers remain unclear.

Purpose: To investigate the effects of motor fatigue on spatiotemporal gait parameters under single- and dual-task conditions in individuals with CAI compared with copers.

Methods: Thirty individuals with CAI (mean age 26.7 ± 7.2 years) and 30 age- and sex-matched copers, (mean age 24.48 ± 6.2 years) completed gait trials under single- and cognitive dual-task conditions, both before and after a fatiguing exercise protocol. Spatiotemporal gait parameters were recorded, and repeated-measures ANOVA with Bonferroni correction was used to examine main effects and interactions.

Results: Dual-tasking significantly altered gait in both groups, with increased step length (p = .005) and step time (p < .001) and reduced step width (p = .018) and step length variability compared with single-task walking (p = .036). Fatigue further modified spatiotemporal parameters. The individuals with CAI showed increased variability in step length, while copers demonstrated decreased variability in step time (p = .021). Cognitive performance remained stable across conditions.

Conclusion: Dual-tasking and fatigue interact to shape gait differently in CAI and coper groups. Rather than uniformly impairing gait, dual-tasking sometimes promoted more consistent walking, while fatigue destabilized gait, particularly in individuals with CAI. These findings highlight the importance of incorporating both cognitive and fatigue-related challenges into rehabilitation to better prepare individuals with CAI for real-world demands.