Impact behaviors of human knee joint during triple-jump based on multi-body dynamics and finite element analysis

In order to better understand the effects of triple-jump movement on jumpers, impact behaviors of left knee joint of a healthy man athlete were studied. Based on CT and MRI scanning pictures of the jumper's knee joint, a three-dimensional model was built, including complete femur, tibia, fibular, patellar, cartilages and main ligaments of the knee joint. Then, a method combining finite element analysis (FEA) and multi-body dynamic analysis (MDA) was used to simulate a real human triple-jump. Finally, the loading data, such as, muscle force and joint reaction obtained from an MDA were impulted into a finite element model to compute stress, strain and displacement variations of the knee joint under impact conditions. The numerical simulation results showed that the stress, stain and the displacement of medical cartilage are larger than those of lateral cartilage; the contact force and contact areas increase with increase in load, consequently, this can incur severer wear contours of the knee joint and badly injure the jumper. The computation results matched reasonably the research results in the published literatures. The results demonstrated the importance of performing MDA as a preliminary step to FEA in biomechanical fields, and the proposed method had a potential to generate a better understanding of injury mechanisms of jumpers.