"At GORUCK events, people's foot care is surprisingly poor," said the former ultra runner somewhere around Mile 20. I smarted at the comment, but I couldn't deny it: the inside of my own boot was slowly grating my little toe like parmesan. ... This was the first time I'd encountered a serious distance runner, though, and it became clear that that community was privy to an advanced science of foot health as foreign to the rest of us as architecture was to Visigoths and Huns.