Development of Tensioning and Braking Mechanisms for Lower Limb to Reduce the Load on Anterior Cruciate Ligament in Landing Motion

Abstract

Anterior cruciate ligament (ACL) injuries are among the most common ligament injuries, with one contributing factor being excessive knee valgus angles during the landing motion after jumps. In this research, the authors have worked on an approach to constrain knee valgus motion by applying mechanical stimuli to the lower limb. As an approach of applying stimuli, we focused on the tension transmission pathway through myofascial and the mechanoreceptors in the toes, which contribute to the body motion coordination. Based on this pathway, we placed a wire along the surface of the lower limb and developed two mechanisms to constrain knee valgus motion using wire tension. The first one is a tensioning mechanism that allows for adjustable wire tension, enabling investigation of movement conditions that influence valgus motion during landings. Second one is braking mechanism that incorporates a mechanism to brake the wire only during landing in knee valgus motion, for use in practical situations. The knee valgus angle measured in the jumping experiments indicated that each device could affect constraining valgus motion.