Almost a decade ago I borrowed a book from my school library, which held the tale of a young Native American (if I remember correctly) boy who wanted to become the fastest one from his village, for his life dream was to become the village's mailman, who basically had to have a good memory and be very fast as to run from one place to the other. The kid had a friend who was faster than him and helped him achieve his dream. At one point in the story, the boy has to deliver a message that was crucial for the village, about an imminent enemy, I believe, and at his attempt, he completely ruined his legs in a non reversible way. Eventually he made a family and became a farmer, for he could no longer run, but was content he managed to achieve his dream, albeit briefly, and help his people.
I don't remember the title, author, or anything other than the story. It was a somewhat small book, since the story isn't that long. I read the book in Greek. What book is this?