Originally Posted by Szczuldo

then it's your pedal stroke, your hips should not be rocking back and forth when you are on the saddle. Wait...are you mashing? if so then your probably moving your entire body so you can put enough force on the pedals and in doing so you are making yourself less efficient. Maybe try spinning a larger gear and see what that does for you. You should also consider getting rollers, those will help smooth your pedal stroke.