The effect of muscle activity on knee flexion and extension in single-leg landing

Introduction & Objective: Landing is one of the common movements that can create an impact force of ۲ to ۱۲ times the body weight. This mechanical impact must be adjusted through the musculoskeletal system. The increase in impact forces during landing and the repetition of these forces are the basis for structural injury. The maximum vertical forces of ground reaction appear due to impact during landing, and the magnitude of these forces is related to the delay in their time. It has been reported that ۷۰% of knee injuries occur during landing from a jump, and the knee joint is the main part of the body that plays a role in absorbing and adjusting landing forces when landing from a jump. Various research has been conducted in this area, for example, Asaeda et al. in ۲۰۲۴ investigated the biomechanics of the lower limb during the execution of the single-leg landing movement under the influence of the presence or absence of fatigue. Also, in ۲۰۲۰, Park et al. investigated the biomechanics of lower limb landing during a single leg landing after joint cooling. This study aims to investigate the effect of muscle activity on knee flexion and extension in the sagittal plane of the knee joint at the moment of a single leg landing.