Atrayu

Okay so, I write casually in my free time. Usually medieval fantasy. There are generally horses in the story somewhere. I always find myself wondering random things like... how fast can a horse run? How long can it run at top speed before needing to rest? What happens if it isn't rested and is made to continue running?

Questions like this plague me, especially since I really don't want to buy a whole book on horses just to get these simple answers. heh. Anyone have any helpful info for me regarding these questions?

Thanks.