Active Variable Compression-Shoes: Design and Evaluation of External Ankle Supporter to Prevent Ankle Sprain via Active Compression Mechanism

To increase ankle stability and avoid the degradation of physical ability, variable stiffness must be provided to the ankle joint in real-time. However, the existing methods to ensure this suffer from various problems. Thus, this study proposed a novel type of external ankle supporter named active variable compression shoes (AVC-Shoes) utilizing a wire-fabric mechanism. The design of the AVC-Shoes was inspired by the “heel locking taping” technique aiming to apply a compression force to the talocrural and subtalar joints, which are crucial for ensuring ankle stability. Furthermore, we customized the upper portion of the shoe to maintain physical capability without restricting natural motion. In addition, algorithms for variably adjusting stiffness during walking and in situations of ankle sprain were implemented. The experimental results confirmed that AVC-Shoes could variably adjust stiffness in the ankle joint in all directions, thus effectively increasing the time delay before an ankle angle change occurred in the event of a sprain.