Effects of Tai Chi training on lower-limb coordination pattern and variability during walking in patients with functional ankle instability: a pilot randomized controlled trial

Functional ankle Instability (FAI) is a common sequela of ankle sprains, characterized by recurrent “giving way” sensation and functional deficits associated with impaired lower-limb proprioception, neuromuscular control, and postural control. While Tai Chi, a traditional mind-body exercise, has been shown to positively affect balance ability and self-reported instability in patients with Chronic Ankle Instability (CAI), but its influence on lower-limb coordination patterns remains unclear. This study aimed to evaluate the effects of a 12-week Tai Chi intervention on the clinical outcomes and lower-limb gait coordination patterns in patients with FAI. A single-blinded randomized controlled trial was conducted, recruiting 28 FAI patients who were randomly divided into a Tai Chi intervention group and a health education control group. The Tai Chi group underwent 12 weeks of simplified 24-form Tai Chi training. Primary outcomes included lower-limb joint coordination patterns and coordination variability during walking, quantified using the Vector Coding technique via three-dimensional motion analysis system. Secondary outcomes included the Cumberland Ankle Instability Tool (CAIT) and the American Orthopaedic Foot & Ankle Society-Ankle Hindfoot Scale (AOFAS-AHS) scores, were also assessed pre- and post-intervention. Post-intervention, both groups showed improvements in CAIT and AOFAS-AHS scores, however the Tai Chi group exhibited significantly higher CAIT and AOFAS-AHS scores compared to the education group (P < 0.01). Regarding gait coordination patterns, the Tai Chi group showed a significant reduction in Hip-Ankle Pro-phase in the transversal plane and Knee-Ankle Dis-phase in the coronal plane (P < 0.05). No significant changes were observed in other coordination patterns. No significant between-group differences were observed in coordination variability. A 12-week Tai Chi intervention effectively improves subjective ankle stability and function outcomes in FAI patients. Furthermore, Tai Chi may enhance motor function in patients with FAI by suppressing maladaptive proximal compensatory strategies and improving distal joint dynamic control. These findings provide biomechanical evidence supporting the use of Tai Chi as a rehabilitation strategy for FAI.