> Consider that the mental aspect of a race is inversely correlated to the distance of a race
I disagree with your quoted statement. I'd say the mental aspect is equally important in the 1/2 marathon as it is in the 5k. In the 1/2s I ran, the mental part was mostly fighting fatigue, whereas in the 5k, it was mostly fighting through pain (and fatigue too, but anaerobic fatigue instead of aerobic)