The mental marathon
Running is a mental activity, even though you might think otherwise. Even though you need good lung capacity, core strength, and leg strength, it's still mostly mental. I don't know about short-distance running, but anything above 10k is a mental sport where you are pushing yourself to the limits on a regular basis.
The thought process going on in the mind of a long-distance runner is something like this:
- At the start: "Should I really run? Maybe I can stop now because I haven't covered much distance anyway, and I'm not feeling it today."
- Halfway through: "I already completed half the course; just have to keep up until I finish. Just focus on your breath and take one stride at a time."
- Near the end (last few laps): "Man, I love running. My body feels amazing; I wish I could make this feeling last longer."
- A few hours after finishing: "Man! My legs are sore. My knees took a beating today; I shouldn't have gone in the first place." (You guessed it, it will happen again.)
This translates to other parts of your life. You develop resilience and equanimity through running.