I believe that mindset also has alot to do it..

Just like lifting weights increases your strength in body, life increases your strength in mind.

When times get tough and you want to give up, it's your mindset that keeps you pushing on through the pain and discomfort.

Add mindset to a solid base of fitness, improvements in training methods and increased pain tolerance - as you mentioned - and you're left with a high calibre, ultrarunning machine.

Thanks for sharing this article and good luck on your running adventures 😊