"I can't even reach them."
The runner on my left shares an amused look with me as we both stretch uselessly upwards. He gives up and jogs around the monkeybars, one of a dozen or so obstacles in the 11km Survival of the Fittest race in Nottingham. But I'm not quite ready to bail. Experimentally, I grab the vertical pipe that supports the bars with both hands, pull myself upwards, then transfer one hand, then the other, to the bars. Even on the wet, muddy steel, my grip holds.
I wasn't expecting that to work. I start swinging forwards.
"If you can't make it, feel free to just do as much as you can!"
The faux drill instructor supervising the obstacle perhaps thinks that that passes for encouragement - or maybe he's using reverse psychology.
In front of me, a big guy falls off. I'm moving so fast that I catch up to the racer in front of him and, swinging out of control, nearly kick him in the back.
I clear the bars and run on.
They chuck a few other obstacles at us, but only the freezing swim across the river gives me trouble. The waterslide into the water is great fun, but by the halfway point I'm flagging as the cold eats into my strength, and starting to get worried. After I haul myself onto the muddy bank, I stagger for a few metres, unable to immediately run - and my skin feels like it's burning. But that's the only point that's hard.
Approaching the end of the course, still running, I'm cold and I'm hungry, but I'm not tired, and I'm finding that genuinely surprising. But if you do enough of something you inevitably, imperceptibly, get good at it. The body changes slowly, but the mind's perception of it changes more slowly still.
Of course, just before the finish line, I come up against the Wall of Fame - an eight-foot, sheer, rain-slicked barrier. The runners in front of me are jumping, scrambling, grasping hands offered by people sitting on the top, disappearing over the other side. I know that if I can just get my fingertips on top of that wall I can haul myself up and over. I charge at it, leap.. and don't even come close.
The runner behind me gives me a boost. I pause on the top to offer her a hand up, but she doesn't need it.