Quantitative assessments of static and dynamic balance performance in patients with chronic ankle instability.

Patients with chronic ankle instability (CAI) have postural-control deficits during center-of-pressure excursions than do healthy individuals. While an external analysis of center-of-pressure excursions in CAI has been performed, a quantitative analysis of center-of-gravity movements, to detect the balance deficits associated with CAI, has yet to be performed. Therefore, the aim of the study is to quantify the balance deficits in patients with unilateral CAI.Forty-four patients with unilateral CAI (24 men; age, 31.7 ± 5.5 years) and 26 uninjured volunteers (12 men; age, 28.6 ± 5.9 years) underwent Neurocom Balance Manager assessments of dynamic and static balance responses in limits of stability, unilateral stance, and forward lunge tests.In the limits of stability test, there were no significant group differences in the forward direction; however, reaction times were longer in the CAI group than in the control group in the backward (P = .037, effect size [ES] = 0.49) and rightward directions (P = .032, ES  = 0.47). Furthermore, the CAI group showed more excursions in the rightward (P = .046, ES = 0.50) and leftward directions (P = .002, ES = 0.80), and less directional control in the leftward direction (P = .036, ES = 0.59). In the unilateral stance test, the center of gravity sway velocity was faster in the CAI group than in the control group, whether eyes were opened or closed (P < .05). There were no significant group differences in forward lunge-test outcomes.Patients with CAI have poor static and dynamic balance performance compared to that in healthy counterparts. Thus, balance retraining should be an essential component of rehabilitation programs for patients with CAI.