The proposed study consists in moving several bones such as pelvis, femur and tibia in conditions as similar as possible to those obtained in a walking subject, to evidence the functioning of this hip and knee joints. The analysis is performed during the stance phase when the joints are loaded. This study is the first phase of a research consisting in: (i) the visualization of the motion of joints in both normal and pathologic subjects; and (ii) the calculation in real time of articular loading caused by muscular forces when sustaining both the external and inertial loads. This research will provide the kinematic and dynamic boundary conditions applied to both a knee and a hip prosthesis of the patient in movement.