I know this, but never paid attention to it. The issue is that in my area, I can either run on a sidewalk, the street, or a treadmill, and I can't stand treadmills. Might just stick with biking for the foreseeable future.well, unless your life depends on it, no running on concrete.
It kills me that my son's old High school had their track around the football field paved. that is insane.
gym floors are glorified concrete.
Those are not sport surfaces.