In recent decades, the technological progress has contributed to the development of appliances that significantly improve human life. The biomedical field has benefited more than others from this innovation process. In particular, robotics advances have led to the development of prostheses that allow who suffered the amputation of a lower limb to walk almost like a healthy person. Although sophisticated, the current solutions are not yet able to completely reestablish the function of their biological counterpart. According to authors' opinion this deficiency is principally due to the lack of suitable development and verification methods rather than of appropriate technology resources. Therefore, an innovative bench for testing lower limb prostheses considering working conditions more realistic than those defined by the legislation in force is presented in this paper. The mechanical setup is composed of a 6-axis industrial robot and a custom 2-axis active force plate. The first one is used to replicate the movements of the limb residual segment in space. The second one to load the prosthetic foot both in longitudinal and vertical direction, that is, in the sagittal plane. Both the design choices and the operation procedure are illustrated. Then, a numerical model of the bench is developed in order to assess the merits and the limits of the proposed solution.