chronic ankle instability

Examining Postural Control With and Without Visual Feedback in Individuals with history of Ankle Sprain

Lateral ankle sprains are common orthopedic injuries and often result in chronic ankle instability (CAI). Studies have shown that the CAI population typically has decreased ankle proprioception and possibly a greater reliance on visual feedback when compared to healthy controls. However, little is known about how the postural control characteristics change in those with and without CAI when external visual feedback is manipulated. Purpose: To compare postural control characteristics of persons with CAI, Copers and healthy adults when performing a single leg balance test with and without external feedback. Method: The definition for CAI used for this study includes persons who have experienced recurrent ankle sprains, in addition to self-reported “feelings of instability” and “giving way,” and a score on the Identification of Functional Ankle Instability (IdFAI) of 11 or greater. 18 participants with CAI, 15 Copers, and 18 healthy controls (mean age of all groups: 22 years) performed the Athlete Single Leg Test on the Biodex Balance System (BBS) at Level 4 which involved a high degree of platform instability. All participants completed 2 trials without and with feedback in that order. Center of pressure position was recorded and the two trial mean was used for further analysis. Overall stability index (OSI) defined as the mean distance of the center of pressure from the center of the platform was obtained from the system. Sway area was calculated using custom Matlab script. Separate 3 (Group) x 2 (Feedback) mixed ANOVAs were run using overall stability index (OSI), and sway area as dependent variables. Results: Significant feedback main effect showed participants had significantly lower (better) OSI value with feedback (1.4±0.1) compared to without feedback (2.6±0.2; P < 0.001) but sway area with feedback (8.61±2.33cm2) was similar to without feedback (10.94±2.43 cm2). There was no significant group main effect or interaction observed for either of the variables. Conclusion: Results suggest that external visual feedback may not play a significant role in helping persons with CAI improve their postural control.
Listed In: Orthopedic Research, Physical Therapy


Chronic ankle instability (CAI) patients often exhibit altered walking mechanics, due to strength and proprioceptive deficits associated with CAI. Reduced strength and proprioception function may alter walking energetic patterns, by reducing energy absorption and generation capability. It is unclear whether strength and proprioceptive training can affect walking energetics for CAI patients. PURPOSE: To examine the effect of a 6-week ankle and hip rehab program on ankle, knee, and hip joint energetic patterns during walking in CAI patients. METHODS: 15 CAI patients (23 ± 2 yrs, 178 ± 8 cm, 76 ± 9 kg, 83 ± 7% FAAM ADL, 56 ± 10% FAAM Sports, 3.6 ± 1.1 MAII, 4.7 ± 2.0 ankle sprains) performed ankle and hip strength and proprioceptive exercises (i.e., theraband, wobble board, etc.) 3 times per week, for 6 weeks (rehab group). 14 CAI patients (22 ± 2 yrs, 177 ± 9 cm, 75 ± 12 kg, 81 ± 9% FAAM ADL, 56 ± 12% FAAM Sports, 3.4 ± 1.2 MAII, 5.9 ± 3.3 sprains) performed no rehab exercises (control group). We measured ankle, knee, and hip joint power during walking for all patients before and after 6 week duration. Functional statistics (α = 0.05) were used to evaluate the influence of the rehab exercises on joint power for both groups across the entire stance phase of walking. RESULTS: The rehab intervention resulted in up to 0.07 W/kg more positive ankle power (concentric) between 19 and 26% of stance and up to 0.06 W/kg more positive knee power (concentric) between 40 and 48% of stance. No changes were detected in hip joint power during the stance phase of walking. CONCLUSION: Strength and proprioceptive training resulted in an improved gait energetic efficiency via increased ankle and knee power generation during mid-stance. As greater muscular strength can lead to an increase in power absorption and generation, the intervention focusing on strength could be beneficial in improving walking energetics in a CAI population.
Listed In: Biomechanics, Gait