Stability and performance are two main issues in motion of bipeds. To ensure stability of motion, a biped needs to follow specific pattern to comply with a stability criterion such as zero moment point. However, there are infinity many patterns of motion which ensure stability, so one might think of achieving better performance by choosing proper parameters of motion. Step length and step period are among major parameters through which we control our motion. Change of these parameters results in change in pattern of motion and consequently affects major characteristics of motion such as stability, speed and energy consumption. In this paper we used genetic algorithm for stable path planning for motion with different values of step length and step period. Considering actuators limit, feasible domain of motion is found. Then maximum feasible speed and consumed power is calculated and reported.