Recent trends in the field of anthropomorphic robotics involve approximation to the motion characteristics of the robot kinematics of a human body. The problem of high energy consumption in implementation of the kinematics of an anthropomorphic robot is partially solved by reduction of the weight of a design. In this regard, of special interest are the developments concerning the study of the stability of the structures and materials capable to withstand the set loads. In this paper a research was done of the stability of the basic structural elements of the lower extremities of Antares anthropomorphic robot under the influence of the external forces, such as straight-line power and twisting. The design of Antares robot employs actuators Dynamixel MX-64T and MX-28, the gears are made of a metal, which allows the robot to move with a given accuracy and a margin of safety. During modeling the assembly of the lower extremities were subjected to simulation of 2 types of loads, those were torque and "direct force" orientated in three directions: vertical (perpendicular to the transverse plane), lateral (normal to the front plane) and lateral (perpendicular to the sagittal plane). The direction of the applied force was selected on the basis of the fact that this force would have its maximal value, when the leg will be in a "sitting" position, therefore, the direction would be directed along the normal to the sagittal plane of the leg. In order to test the leg for twisting a situation was modeled, in which the robot was in the lying position with the inner part of its foot resting on the floor surface. During the study the values of the actuators' torques, intended to move the robot in space, were determined. The moments of rotation of the engine output shaft in a robot leg were determined: ankle, knee, hip joint. The maximal values of the rotational moments, able to withstand the construction of the hip and the thigh of 5 Nm and 5.2 Nm, respectively, were determined. During the simulation it was also found out that raising of the robot from "a sitting position" required 2.4 times less effort than the maximal torque developed by the engine, and the design of the leg could withstand the maximal torque of the motor rotation. On the basis of those data a conclusion was made, that the robot was able to jump in the vertical plane, and later this was proved successfully in real experiments.