Yes, the mental fortitude is much overblown aspect.
Yes, there is this thing as mental fortitude and you can even train it to persist to run hard, especially when you "kick" at the end of a race.
But this only helps to a very small degree, the most of the result is due to more mundane aspects like your experience with running, your running efficiency, your aerobic capacity, your additional fat you are carrying with you, whether you have been running regularly recently, etc.
I am regular runner (10 miles every morning). If I have an injury and are out of running for two months, I will have very hard time at the same speed and duration as before the injury and no mental fortitude will help me get the same result come race time. My mental fortitude counts for less than my last two months of running history.
Even just a tiny bit of experience with running can dramatically improve your results. And that is not necessarily by improving your fitness. I remember when I started running I would get large increases in results every single day. I was very proud of myself until somebody told me this is normal and has nothing to do with my fitness -- my brain is getting rewired to coordinate my movements better and this helps running efficiency. Another important aspect of running you learn within first days is how it feels to be running at a sustainable pace. If you don't have any experience you are very likely to run too fast, accumulate lactate and be unable to finish the distance or have to slow down considerably. Because you don't have any idea how hard is appropriate for the challenge and your ability.
And one more argument against mental fortitude. I think it has very little value the better you are at running. The better you are at running the closer you run to your physical limits and once you understand it, the brain alone cannot make you run faster if your body simply is not able to produce required output.
If you observer Eliud Kipchoge, for example, beating yet another marathon record, you will notice he is feeling good and smiling throughout the race and at the finish line. Yes, there is probably some pain and discomfort but really, he is just executing a meticulously prepared plan. The work has already been done and he can't run faster than his ability and he knows is ability to perfection. He knows if he runs even a tiny bit faster than he should, it will actually put him above his ability and produce a slower result. There is maybe last couple miles where he is judging his reservers and decides whether to run a tiny bit faster or stay at his plan and that's about it.
I had to use mental fortitude to finish my first marathon (when my body cut the power at 20 miles), but that's just because I was undertrained and unprepared. Now when I run I know perfectly the pace I need to keep to finish the race and there isn't temptation to "push it" because I know if I do this it will produce a worse result.
(yes, I know running long distance like 5k-42.2k is very different from sprinting. I am just an amateur who runs a lot who is also a nerd and want to understand a lot about everything I do.)
Your observation on neurological efficiency generalizes to all physical activities.
If you practiced pull-ups every day, you would become very efficient at pull-ups and possibly double the number you can do. At the same time, it isn't impossible for seemingly related measurements of strength (such as the biceps curl and deadlift) to get worse as your body "overfits" its adaptation to the pull-ups.
It is less impressive than you think. I run slow all the time (zone 1/zone 2) and only very occasionally do tempo/threshold/intervals. I only add those in my marathon training block.
The distance is only one factor, the other factor is intensity. If you keep intensity low you can increase the volume a lot.
Most untrained people get their heart rate up to zone 2 by just walking a little faster or in more difficult terrain. But they can easily walk fast for an hour or two. The only difference is that I have to be running to get to the same level of exertion.
My runs are all easy and enjoyable and I don't have to fight myself to go out and I feel perfectly fine right after the run. I run 10 miles because that's about 1h 15-20 minutes which is the most I can pack into my busy morning. I am using that time to rethink some stuff, listen to the news or audiobooks so not all time is lost.
An interesting feature of running is that if you do it correctly you can be quickly progressing to doing things that couple of months ago you thought impossible. For example, what once was a very strenuous run was an easy stroll couple months later, if I did things correctly inbetween.
Another example, for years I had trouble with my Achilles tendon which would flare up every time I reached particular weekly mileage (about 20-30 miles). For many years I thought I am never going to be good at this, but then I got an advice from my physiotherapist to do some strength training and calisthenics targeting my Achilles and my problems suddenly went away. From then on I understood it is all about problem solving and I am a nerd.
Running isn’t an activity where you need much mental fortitude.
But in sailing in 10 Beaufort or climbing in extreme weather it is all about mental fortitude not physical strength or training. Some people just quit, give up and others stand at the steering wheel for 6 hours despite soaked clothes and blowing gale.
In extreme weather, the weather is what is testing your mental fortitude. In many such situations you can’t “just quit” once you have entered the conditions, other than essentially committing suicide by ceasing to protect yourself. You can’t turn off the weather and go home just because you’re unhappy.
In running, it is your own body that is testing your mental fortitude. To be more specific, it is the extreme physical discomfort one experiences while training and competing. And unlike life-or-death extreme weather, you really can quit at any point. It is a totally optional activity at all times. So yes, it requires quite a lot of mental fortitude to keep doing something so physically unpleasant, every day, in pursuit of a personal goal.
Heck, I am observing candidates giving up during interviews or experienced software engineers giving up during outages. I would say both also require mental fortitude.
I mean, I’ve quit an interview process several times - usually because they were dragging it out, or because the interview process hinted to me I’d not enjoy working there.
Interviews are bidirectional information exchanges - the company is also pitching itself to the candidate during the process.
Yes, there is this thing as mental fortitude and you can even train it to persist to run hard, especially when you "kick" at the end of a race.
But this only helps to a very small degree, the most of the result is due to more mundane aspects like your experience with running, your running efficiency, your aerobic capacity, your additional fat you are carrying with you, whether you have been running regularly recently, etc.
I am regular runner (10 miles every morning). If I have an injury and are out of running for two months, I will have very hard time at the same speed and duration as before the injury and no mental fortitude will help me get the same result come race time. My mental fortitude counts for less than my last two months of running history.
Even just a tiny bit of experience with running can dramatically improve your results. And that is not necessarily by improving your fitness. I remember when I started running I would get large increases in results every single day. I was very proud of myself until somebody told me this is normal and has nothing to do with my fitness -- my brain is getting rewired to coordinate my movements better and this helps running efficiency. Another important aspect of running you learn within first days is how it feels to be running at a sustainable pace. If you don't have any experience you are very likely to run too fast, accumulate lactate and be unable to finish the distance or have to slow down considerably. Because you don't have any idea how hard is appropriate for the challenge and your ability.
And one more argument against mental fortitude. I think it has very little value the better you are at running. The better you are at running the closer you run to your physical limits and once you understand it, the brain alone cannot make you run faster if your body simply is not able to produce required output.
If you observer Eliud Kipchoge, for example, beating yet another marathon record, you will notice he is feeling good and smiling throughout the race and at the finish line. Yes, there is probably some pain and discomfort but really, he is just executing a meticulously prepared plan. The work has already been done and he can't run faster than his ability and he knows is ability to perfection. He knows if he runs even a tiny bit faster than he should, it will actually put him above his ability and produce a slower result. There is maybe last couple miles where he is judging his reservers and decides whether to run a tiny bit faster or stay at his plan and that's about it.
I had to use mental fortitude to finish my first marathon (when my body cut the power at 20 miles), but that's just because I was undertrained and unprepared. Now when I run I know perfectly the pace I need to keep to finish the race and there isn't temptation to "push it" because I know if I do this it will produce a worse result.
(yes, I know running long distance like 5k-42.2k is very different from sprinting. I am just an amateur who runs a lot who is also a nerd and want to understand a lot about everything I do.)