OBJECTIVES
Chronic Ankle Instability (CAI) often recurs following an initial Lateral Ankle Sprain (LAS). CAI not only impairs ankle joint movements but also disrupts muscle activity due to altered proprioception signals between ankle ligaments and the central nervous system. Consequently, biomechanical imbalances ensue, elevating the risk of additional musculoskeletal complications like posttraumatic osteoarthritis. To effectively manage and rehabilitate CAI, comprehensive analysis is crucial. In this regard, gait analysis stands as an invaluable tool for both biomechanical research and functional recovery. While existing research primarily uses stable surfaces for standardized results, recent findings indicate that unstable terrains like sand could offer rehabilitation advantages. However, studies focusing specifically on CAI patients remain relatively sparse. Therefore, this study aimed to conduct a comparative analysis of the gait characteristics in CAI patients on sand and paving blocks.
METHODS
This study included 30 participants (15 CAI patients and 15 controls) using randomized cross-over designs. CAI patients were selected based on having experienced a LAS at least 12 months prior and scoring 27 or lower on the Cumberland Ankle Instability Tool. Participants were asked to walk on both sand and paving blocks. To compare and analyze gait characteristics based on different types of surfaces, changes in the joint angles of the lower limbs during the gait cycle were analyzed using curve analysis and one-dimensional statistical parametric mapping. Spatiotemporal parameters and motor units were analyzed using a two-way repeated measures analysis of variance (Two-way RM ANOVA).
RESULTS
According to preliminary results, patients with CAI demonstrated significant differences in knee joint angles when walking on sand compared to paving blocks, particularly during 64.91% to 74.39% of the gait cycle (P=0.008). Additional differences were noted in motor unit variables including the number of motor units recruited, recruitment threshold, and mean firing rate.
CONCLUSION
Walking on sand substantially changes walking kinematics compared to walking on paving blocks and may cause greater postural instability in CAI patients. Therefore, walking on sand can be considered an alternative to improve postural control in patients undergoing walking rehabilitation.