At such extreme distances your emotions are stretched taut like tendons ready to snap at the slightest touch. I wanted the world to stop. I wanted to cry like a baby and crawl home to mummy. I realised a painful, humiliating truth: I'm no kind of super athlete. I'm a wuss.
On hearing the news about Boston, I'm guessing runners and endurance athletes everywhere experienced an extra painful stab of empathy. To detonate bombs at that exact place and time, right at the sharpest end of the event, requires a very deliberate level of maliciousness.
The marathon is so much more than just a really long run. You come face to face with your own limits. The demons you confront in any endurance event are yours and yours alone.
At least, that's the way it should be. How obscene to have someone else's demons murdering people at the finish line.
When the bombers are eventually caught they should be made to run their own marathon. Barefoot. No interrogation, no questions, just push them on to the road and make them run. Maybe follow them with sharp sticks to help keep the pace up. And no physio at the end.
Ah, sweet retaliation. Check me out, stooping straight to the level of bitter fantasy.
I lose hope as I try to comprehend how anyone can be so callous and intentional about hurting other human beings. This kind of tragedy throws me into a spin of disbelief, fear, grief and anger, all of it twisted up with a degree of morbid curiosity that I try to hide from myself as I watch the internet footage from multiple angles.
It's pertinent to note that on the same day as the Boston marathon more than 50 people were killed in coordinated bombing attacks across Iraq. Reports say it was that country's deadliest day since March 19.
Hang on, what happened in Iraq on March 19? Oh. More bombings, another 50 people dead.
The horror of all this hits me at an intellectual level, but my Western bias means I am somehow more deeply affected by the Boston explosions. This shames me. What makes a man, woman or child's suffering any less significant just because they live on one patch of the Earth instead of another?
It makes me wonder if my insulated world view is part of the wider problem. Most of my education on global politics comes from movies, after all.
Whatever the case, from Boston to Baghdad we need to get our heads checked. We need to smile at our neighbours more and maybe even go running together. Surely humanity can do better than blowing up civilians.
Marcel Currin is a Tauranga writer and poet.