I’ve been running uphill for over an hour, scaling this narrow mountain trail, when we pass through some trees. This must be the top, I’m thinking, hopefully, as we crest the pass. But alas, rising up on the other side are more hulking mountains and snaking up through the middle of them, like a line of ants, are the tiny dots of the runners ahead of us.

“Putain,” swears the French runner behin...