Analysis of actuating forces and joint reaction forces are essential to determine the capacity of actuators, to control the system and to design the components. This paper presents an algorithm tha t calculates actuating forces(or torques) depending on the various driving types to produce a given system motion. The joint reaction forces(or torques) of multibody systems with closed-loops are analyzed in the Cartesian coordinate space using the inverse velocity transformation technique. Two numerical examples were carried out to verify the algorithm proposed.