The Effect of Restricted Ankle Dorsiflexion on Knee Injury Risk During Landing

<i>Purpose</i>: This study utilized a combination of musculoskeletal modeling and finite element analysis to investigate the effects of varying ankle dorsiflexion ranges on knee joint loading, soft tissue stress distribution, and the coactivation patterns of muscles surrounding the knee during landing. <i>Methods</i>: Based on the Weight-Bearing Lunge Test (WBLT), a total of 32 basketball players into two groups: normal dorsiflexion (ND) and limited dorsiflexion (LD) and conducted six countermovement jumps (CMJ) while collecting motion and force data. Personalized musculoskeletal models were created using OpenSim to analyze kinematics and kinetics, and Helium-free MRI and CT scans were used for finite element modeling to assess internal tissue stress in the knee. <i>Results</i>: During landing, the patellofemoral joint contact force in LD was reduced compared to the ND. The coactivation of muscles around the knee joint decreased. The von Mises stress in the tibial cartilage, meniscus, anterior cruciate ligament and posterior cruciate ligament were elevated. <i>Conclusions</i>: The results suggest that increased ankle dorsiflexion during landing may effectively reduce internal tissue stress in the knee joint while enhancing muscle coactivation around the knee joint and increasing patellofemoral joint contact force. These findings provide valuable theoretical support for strategies to reduce the risk of knee injuries during landing. Additionally, they offer reliable technical approaches and theoretical insights for studying injury mechanisms in other sports activities, such as running and lateral jumping.