Employing a spring element explicitly as a robot leg, we can reproduce the structure of a robotic leg module equivalent to animal's leg with muscles. And, in order to improve the moving speed of such a robot, mechanical structure (hardware) and motion control (software) referring to an actual animal should be taken into consideration. In this study, aiming at clarifying the efficient kicking by the legs of the robot with spring elements, we experimentally investigated the influence of three robotic parameters such as "period of the leg swing", "angle of the leg swing", and "total weight of the robot" on the moving speed. As a result, we confirmed that the relationship between each parameter of the robot and the moving speed was nonlinear and very complex.