Effects of Gait Biofeedback and Impairment-based Rehabilitation in Individuals With Chronic Ankle Instability

Individuals with chronic ankle instability (CAI) have demonstrated altered gait patterns. Gait training may be necessary to address these alterations as protocols focusing solely on strength or balance have not been shown to impact walking gait. Biofeedback about the foot position during walking may help improve gait biomechanics. The purpose is to determine whether a 4-week rehabilitation program that includes biofeedback has beneficial effects on self-reported function and ankle gait kinematics compared to rehabilitation alone in people with CAI. The design is a single-blinded randomized controlled trial. Participants will complete baseline self-reported function questionnaires and walking gait trials and then be randomized to complete 4- weeks of supervised rehabilitation with or without audiovisual biofeedback. Follow up emails will ask for participant information about ankle health and to complete questionnaires about their ankle for 6 months and 12 months after completing rehabilitation.

This study will require 10 visits for all participants. Both groups will participate in baseline and follow-up gait assessments involving walking on a treadmill at 1.34 m/s. Follow-up visits will be conducted within 72 hours of the participant's final rehabilitation session. Using a rigid cluster marker setup, reflective markers will be placed on the upper back, sacrum, and bilaterally on the thigh, shank, rearfoot, and forefoot. A 5-minute familiarization period will be completed to ensure participants are comfortable and walking as normally as possible. Following the familiarization period, 1-minute of continuous gait data will be collected. The data collected during baseline and follow-up gait assessments will be used to analyze the primary and secondary outcome measures for kinematics. Participants will also complete the patient reported outcomes (FAAM ADL \& Sport Subscale) at the baseline and follow-up visits.

Impairment-based Rehabilitation:

Four weeks of supervised rehabilitation (8 sessions) will be provided to both groups. This rehabilitation paradigm has been previously reported by Donovan and Hertel. Impairment-based rehabilitation involves identifying and treating deficits in 4 broad domains including range of motion (ROM), strength, balance, and functional exercises by using an "asses, treat, re-assess" approach. Previously reported intervention methods will be used in this study. The clinician administering the rehabilitation will be blinded to the subjects' intervention group status.

Intervention:

Gait training using visual feedback for frontal plane ankle position at initial contact (IC) will be projected onto a screen in front of the treadmill.

Gait Training Protocol:

The goal of this protocol is to improve the position of the ankle at IC using visual feedback gait training over the course of 4 weeks. The intervention group will participate in 2 sessions of gait training per week for 4 weeks using intermittent feedback described by Noehren et al. The Motion Monitor is a software system uses body movements to provide visual feedback to the participant by using information from retroreflective markers on the body that are captured by the cameras. The software will use the position of the rearfoot marker cluster in relation to the shank marker cluster to determine the rearfoot inversion angle at IC and provide visual biofeedback information for the next step. Visual feedback in the shape of a line will be displayed as an image projected onto a screen in front of the treadmill representing frontal plane inversion angle. The line will adjust (similar to a teeter-totter) according to the position of the foot and will change color accordingly. When the ankle position is too inverted, the line will turn red and an audio tone will be heard by the participant. When the ankle position is in a good position, the line will turn green and the tone will not be heard.

Eligibility Criteria:
Inclusion Criteria:

* \>1 Ankle Sprain (\>12 months prior)
* Physically active (\>1.5 hr/week)
* \> 10 on Identification of Functional Ankle Instability (IdFAI)
* \< 90 Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL)
* \< 85 FAAM Sport

Exclusion Criteria:

* Hx of LE fracture
* Hx of LE surgery
* Hx of ankle sprain within last 6 weeks
* Participating in physical therapy for ankle
* Multiple Sclerosis
* Marfan's Syndrome
* Lumbosacral Radiculopathy
* Ehlers-Danlos Syndrome
* Diabetes Mellitus
* Pregnant (self-reported)
* Unable to provide informed consent