Why don’t endurance athletes get tired? Do you remember when you were a kid. Your parents took you on a walk. It went on forever. Soon your energy had gone and your feet hurt. Eventually, and far too late, you ended up back at the car.
If you go out and do the same walk now you’ll discover that it’s not so far.
This story teaches us two things about long distance running.
Runners Start Like Children
The first is that runners are no different to that small child. When we start off we are full of energy. As we run further and further the aches and pains increase until it seems that we are running on willpower not strength. I’ve cried more as an adult whilst running, than I did on those ‘super long’ walks my parents took me on as a kid.
Where we are different is that our size and strength means that we can go further and faster. We have also much stronger will power. We carry on with less complaint even though it hurts
Perception of Reality Changes
The second is that our perception of time and distance changes. Having gone out for hundreds upon hundreds of 10km runs I know that they are easy. Having done fewer but still a significant number of half marathons and 2 hour runs they don’t worry me. I’ve done about 50 marathons or runs longer than 4 hours (it may be a lot more I don’t keep count) I know that I will be tired as a result.
As I run more frequently, build up my mileage and become more present in my running, time seems to compress and dilate all at once. I can run a long way, enjoying every moment of it, and be surprised that I have run for hours.
So we do get tired but we have learnt that it is part and parcel of existence. Small children are still learning that.
This answer originally appeared on Quora