Can you think of any ideas regarding running that everyone from your Joe Schmo hobbyjogger to your top level elite to your running scientist to your nutjob runner can agree on? Concepts like increasing mileage to improve performance or raw speed being trainable are examples of clearly debated points. Taking a few steps back, most people agree that running is a healthy activity, but studies show up every so often about long-term distance running decreasing life expectancy or ruining joints, knees, etc. I'm not even sure that everyone can agree on the dictionary definition of "running" as I've seen self-proclaimed runners shuffling along without both feet leaving the ground at once.
I think just about everyone can get behind the need for hydration for ideal performance, even if they disagree on its actual specific effects or the necessary levels. I also think just about everyone will agree that for an individual, running faster corresponds to faster/harder breathing. What else? I've seen some seemingly very simple or self-evident ideas get debated.