Posture adjustment of finite element (FE) human body model is a significant step in accident reconstruction and investigation on pedestrian kinematical and injury outcomes. A rapid posture adjustment algorithm for pedestrian lower extremities was developed to account for realistic joint kinematics during a gait cycle. Under the kinematic constraints from joint anatomy, the algorithm calculated the posture of the lower extremity at any instant of a gait cycle from the open kinematic chain linked by the hip, knee and ankle joints in sequence. Joint motions were predicted based on subject‐specific geometry, following the rules of joint motion based on the literature. Mesh morphing method were implemented to calculate nodal coordinates of soft tissues around the joints.

As an application example, the proposed algorithm was exercised on the midsize male GHBMC pedestrian model and three different walking postures within a gait cycle were generated. These models were used to simulate a typical vehicle‐to‐pedestrian crash scenario. Pre‐crash posture showed significant effect on the injury risks of lower extremities, indicating necessity of taking pre‐crash postures into account for pedestrian injury investigation.