In the life of the long-distance runner, two hard surfaces are familiar. One is asphalt and apparent and the other is like brick and invisible. The first you run on, the second you sometimes have to run through. This is no idle talk. Way back in 490BC, when gels were unknown and alcohol was possibly a refueller, Pheidippides, a messenger, ran 40km to deliver news of a battle and fell dead. Perhaps he, too, had hit The Wall.
Pheidippides' story is a bit more complicated - he apparently ran much further the previous day - but The Wall remains. It's a place of suffering and disorienting exhaustion and it's always lurking, waiting to examine you, asking how much you trained, interrogating your courage. "I call it a dark place," said twice-SEA Games marathon champion Soh Rui Yong.