I'm not a marathon runner (last year during the summer I famously asked someone: "how do you run long distances?"), but my level of respect for the men and women of all ages that train and compete on a regular basis went through the roof once I hit the 30km mark.
I was given advice to not go hard for the first 30k and that once you hit the 30-35k mark something happens to your body.
Well for me it was cramps. In my quads. For 12.2kms.
If you've ever had muscle cramps, you know how they can do this to you:
So imagine that for 12.2kms. Or better yet, for nearly two hours. Yes, two hours of being barely able to pick up your legs cause you have little chainsaws tearing apart your muscle fibers.
Marathoners are a different breed of human being. My hats off to you.
Check out some official race photos of here.