This is a SLIP (Spring Loaded Inverted Pendulum) model based on human running gait analysis. The model is composed of a rigid body mass, a hip joint, a leg spring model, and a contact model with the ground. Additionally, the model includes running velocity control to provide the leg with stability. The simulation shows the leg hopping then moving forward in a running motion as the body mass is supported by the robotic leg.This model was developed by researchers at the Takanishi Laboratory of Waseda University.