When the marathon is in a straight line, you can run left, middle and right. It will be better to run left on the left runway and right on the right runway. However, if you overtake others or get water towels, it depends on the situation. You can run whenever it is convenient. In short, there is no special rule to run that (left, middle and right) side, and you will not be fouled. Of course, if the organizer has a specially marked road section, you should follow the prescribed route.