Association of core muscle strength and endurance with chronic ankle instability- A cross-sectional study

Abstract Background Chronic Ankle Instability (CAI) accounts for over 40% of cases following an ankle sprain, often leading to debilitating and long-term consequences. Emerging research indicated that deficits in core muscle strength and endurance may contribute to the persistence of CAI. The current study aims to investigate the association between core strength and endurance with CAI. Methods A total of 128 participants were enrolled, including 64 participants with CAI (mean age: 22.73 ± 1.929) and 64 participants without instability (mean age: 21.89 ± 1.691). Ankle instability was evaluated using the Cumberland Ankle Instability Tool (CAIT). Core strength was assessed using a pressure biofeedback device, and endurance was assessed using the McGill trunk endurance battery. Between-group comparisons were conducted using the Mann–Whitney U test. Pearson correlation and multiple linear regression analyses were performed to identify key predictors of CAIT, including the interaction effects. Results The CAI group revealed significantly lower endurance in trunk flexors (p = 0.003, r = 0.31) and extensors (p = 0.011, r = 0.26). No significant difference was observed in core strength (p = 0.954). CAIT scores were significantly associated with left lateral flexor endurance (r = 0.28, p = 0.012). The final regression model indicated that left lateral flexor endurance was the most consistent predictor (β = 0.074, p = 0.055), accounting for 70.5% of the variance in CAIT scores (adjusted R² = 0.705). A near-significant interaction effect (p = 0.054) suggested that this association may differ by group. Conclusion Lateral flexor core endurance is a critical factor for functional ankle stability. Integrating targeted core endurance training into the rehabilitation programs for CAI is beneficial. Trial registration: The study was registered with the Clinical Trial Registry of India (CTRI/2023/08/056445) on 11/08/2023.