Athlete's foot !
At first when I heard the name this morning from my friend's blog who liked running, I guessed it as injury caused by physical problem as same as he thought.
But not, it's caused by another problem, Fungus! It's caused by wet and warm atmosphere. And unfortunately he got the disease! He's been treating himself.
Hi Ken, maybe we should use Five fingers socks with the reasons of not only physical,I mean it can be help for running, but also prevent to chemical circumstance for Fungus. And we have to dry our shoes completely after every running.
It was difficult reading above explain with listening to NHK English. www