If you can't walk, walk anyway
Sports are nice because the lessons are often simple.
I was thinking of the middle of the 2013 Kodiak 50 miler up in Big Bear Lake, California. Not the whole thing, just a segment in the middle, from the bottom of Siberia Creek to the top and then over. It is certainly a top three toughest race segments that I ever dealt with. I don't remember how many miles that segment was. Call it seven or eight miles. What does it matter.
There was supposed to be an aid station at the bottom. Maybe there was later, I don't know. I was the third runner to the bottom and there was no one there but a photographer. I wasn't out of water yet, but I would be soon. I didn't fill up at the aid station at the top. It's a running race, not a water carrying race. If you're not going to drink the water—and heading downhill in the shade of trees doesn't require much of it—don't carry it.
As the great philsopher once said: womp womp.
I typically run the uphills. It was my secret weapon. If you can't be fast, be tough. The trail footing was fairly loose rock, not the sort of thing that's worth pushing through, so I walked. Trudged, really. In the sun. Out of water. Scrubby trees. Tightening up. A brown bear cub ran across the trail in front of me. Freeze. No mom to be seen. No water. Switchbacks. Sun. Miles. Only a bag of gummy bears in the pocket of the hip belt I carried my water bottle in. Couldn't break them down, couldn't swallow them. Unscrewed my water bottle lid and tried to lick any remaining water out of the threads. Couple drops there. Caught up to another runner. (Walker. Trudger, really.) On and on and on and on until the aid station table hove into view.
I prefer to get in and out of the aid stations. Don't stop unless you have. Smile and crack jokes, enjoy the company before you're off on the trail again with nothing but the monsters in your head for company. This aid station though... I remember drinking three Cokes. Two other runners (walkers) made it to the station. I headed off down the trail... then off on a side trail to take a moment to excrete blood. Back to the trail. A little more walking. Then the inflection point that I really remember.
Endurance running, like any community of zealots, has a number of insipid cliches. They probably help sometimes. The one that stuck with me is: if you can't run, walk; if you can't walk, walk anyway. There were probably ten or fifteen miles left. Or eight or whatever. I created a game. Run one minute, walk one minute. Run two minutes, walk one minute. Run three minutes, walk one minute. At some point, I didn't need to do the walking anymore. Eventually I caught the three runners from the previous aid station at the next aid station. One of them finished up with me and we got second and third.
It was a hard day. And a long time ago. Just stay upright, moving forward. All focus compressed into a single point. Not all, but some strength comes from within, and once you find what shelf it's hidden on, you know you can come back and find it later if you believe.