Animate footsteps in FPS

I met a problem when i tried to make character walk like in P.T - video

I created camera shake and tried to set parameters. As i could see from the video character moves like z = +0 afterwards it comes to +5 and back to +0 for a seconds or so. So i tried to make my oscillator to amplitude 5.0 and set frequency to 1 and time to 1 sec. And there are a problem. Character moves up and crouches afterwards. So i start to think i chose the wrong instrument for that. How can it be solved?