Clinical effects of targeted forefoot and rearfoot training on dynamic balance, postural stability, gait biomechanics, and joint function in individuals with chronic ankle instability: study protocol for a prospective randomized controlled trial

BACKGROUND: The forefoot and rearfoot can individually contribute to the development of chronic ankle instability (CAI) after an ankle injury. The aim of this study is to evaluate the effects of targeted forefoot and rearfoot stability training on dynamic balance, postural stability, gait biomechanics, and self-reported joint function in individuals with CAI. METHODS: This study is a prospective, single-center, interventional, randomized controlled trial with two comparison groups, either a usual balance training group or a control group. Individuals (18-44 years) with a self-reported ankle instability, a history of at least one ankle injury at least 12 months ago with typical signs of inflammation, two or more episodes of "giving way" within the previous 6 months, and a Cumberland Ankle Instability Tool score ≤ 24 are included. Exclusion criteria include acute injury, lower extremity surgery or fracture, neurological disease, chronic overuse injuries such as Achilles or patellar tendinopathy, and current participation in a targeted ankle rehabilitation program. The primary outcome measures are dynamic balance as measured by the Y-Balance Test and postural stability as assessed by the Modified Balance Error Scoring System. Secondary outcome measures include gait biomechanics measured by 3D gait analysis and self-reported ankle function assessed by the Foot and Ankle Ability Measure. DISCUSSION: Since there is a lack of information regarding the effects of targeted forefoot and rearfoot exercises on ankle stability, this study has the potential to improve future treatment plans and provide healthcare practitioners with an alternative treatment for CAI. TRIAL REGISTRATION: DRKS (German Clinical Trials Register)-DRKS00034295, retrospectively registered on May 22, 2024 (Reason: The study was originally designed as a randomized controlled pilot study; therefore, the first participants were enrolled without registering the study, which was then caught up as soon as possible); URL: https://drks.de/register/de/trial/DRKS00034295/preview .