The Effect of Additional Neuromuscular Training on Peri-Ankle Muscle Morphology and Function in Chronic Ankle Instability Subjects: A Randomized Controlled Trial

Background: Lateral ankle sprain is one of the most common musculoskeletal issues during sports and activities of daily living. This study investigated the effect of combined neuromuscular training and conventional training (including strengthening, range of motion, and balance exercises) on muscle morphology, dynamic balance, perceived ankle instability, and functional capacity in persons with chronic ankle instability (CAI). Hypothesis: The combination of neuromuscular and conventional training programs might result in additional benefits on the morphology of muscle, dynamic balance, and functional capacity in subjects with CAI. Study Design: A single-blind parallel-arm randomized controlled trial. Level of Evidence: Level 2. Methods: A total of 34 participants with CAI were divided randomly into experimental (EG) and control groups (CG). The EG received conventional and neuromuscular training, while the CG underwent conventional training. Cross-sectional areas of the peroneus longus and tibialis anterior muscles were measured using ultrasonography. Measurements included reaching direction distance, ankle instability, and the foot and ankle outcome score, all evaluated before and immediately after 12 intervention sessions and 4 weeks later in the follow-up phase. Results: Repeated-measures analysis of variance (ANOVA) revealed significant improvement in the EG, particularly in the cross-sectional area of the tibialis anterior muscle on the injured side and the posteromedial reaching direction displacement of the Y balance test. Moreover, the EG’s foot and ankle outcome scores increased significantly compared with the CG ( P < 0.05). However, the group effect size ranged from minor to moderate (Hedges g, 0.40-0.73). Conclusion: Combining neuromuscular and conventional training programs yields greater benefits than conventional training alone regarding tibialis anterior muscle morphology, posteromedial dynamic balance, and functional capacity in persons with CAI. Clinical Relevance: The combination of neuromuscular and conventional training programs could enhance muscle morphology, dynamic balance, perceived ankle instability, and functional capacity in persons with CAI.