Man versus Horse Marathon
en.wikipedia.org
en.wikipedia.org
It seems the race is also long-term optimised for humans to win. There are a lot more human competitors (> 10:1 ratio). The prize fund increased by 1000 pounds per year until a human won, no doubt attracting faster and faster athletes in increasing numbers.
The course has also been varied making year on year comparisons difficult.
I suppose so, but that only gets you so far. If you did a human vs F1 race it wouldn't really matter how many humans were competing or how big the prize pool was, the car would still win every time. :p
I couldn't find more information on whether there are other things done to favor human over the house.
Terrain can be tricky.