Background and objectives: Chronic ankle instability (CAI) is a common sequela of recurrent lateral ankle sprains, producing impaired balance, reduced functional ability, and persistent pain. Rehabilitation traditionally targets either distal (foot) or proximal (hip) musculature. This study compared the effectiveness of intrinsic foot muscle strengthening combined with balance training against gluteal muscle strengthening combined with balance training in improving functional outcomes in adults with CAI.
Methods: Forty participants with CAI (CAIT ≤ 24) were randomly allocated in a 1:1 ratio to Group A (n = 20; intrinsic foot muscle strengthening + balance training) or Group B (n = 20; gluteal muscle strengthening + balance training). The intervention ran for 8 weeks, three supervised 45-minute sessions per week (24 sessions). Assessment was performed by a blinded assessor pre- and post-intervention. Analysis used paired and independent t-tests and repeated-measures ANOVA, with significance set at p < 0.05.
Outcome measures: Primary outcomes were the Cumberland Ankle Instability Tool (CAIT) and Star Excursion Balance Test (SEBT). Secondary outcomes were the Foot and Ankle Ability Measure (FAAM), Manual Muscle Testing (MMT), and the Visual Analogue Scale (VAS) for pain.
Results: Both groups improved significantly across all outcomes after intervention (p < 0.001). Group B showed significantly greater gains than Group A in functional stability, neuromuscular efficiency, and pain reduction (all between-group p < 0.001), with very large to extremely large effect sizes (Cohen's d 2.90–5.11). A significant time-by-group interaction confirmed a steeper recovery trend in Group B.
Conclusion: Both intrinsic foot muscle strengthening and gluteal muscle strengthening combined with balance training are effective for managing CAI; however, gluteal strengthening combined with balance training produces superior functional and pain outcomes, supporting a proximal-to-distal, kinetic-chain rehabilitation approach.