Study Design Controlled laboratory study. Background Recurrent ankle sprains associated with chronic ankle instability (CAI) occur not only in challenging sports but also in daily walking. Understanding whether and how CAI alters feedback and feedforward controls during walking may be important for developing interventions for CAI prevention or treatment.
OBJECTIVE To understand whether CAI is associated with changes in feedback and feedforward control when subjected to experimental perturbation during walking.
METHODS Twelve subjects with CAI and 12 control subjects walked on a treadmill while adapting to external loading generating inversion perturbation at the ankle joint. Ankle kinematics around heel contact during and after the adaptation were compared between the two groups.
RESULTS Both healthy and CAI groups showed an increase in eversion around heel contact in early adaptation to the external loading. However, the CAI group adapted back towards the baseline while the healthy controls showed further increase in eversion in late adaptation. When the external loading was removed in the post adaptation period, healthy controls showed an aftereffect consisting of an increase in eversion around heel contact but the CAI group showed no aftereffect.
CONCLUSION The results provide preliminary evidence that CAI may alter individuals' feedback and feedforward control during walking. J Orthop Sports Phys Ther, Epub 5 Aug 2016. doi:10.2519/jospt.2016.6403.