At just 30 years old, Yuki Kawauchi is in a distance running category of his own. As of January 1, he has run the most sub-2:20 marathons of anyone, ever—76. He’s also run the most sub-2:12 marathons of anyone, ever—25. Kawauchi—one guy—has run more sub-2:10 marathons since 2011 than the whole United States put together. … Rupp, like most athletes at that level, ran two marathons in 2017. Kawauchi ran 12.
The confidence that is built by doing ultra long-distance jogging, the knowledge in the second half when things are getting tough that I’ve run 50 km and 100 km so I know for sure that my stamina isn’t going to break in the second half. The internationals running next to me haven’t done 100 km so I know that my legs are the ones that are still going to keep moving when things get down and dirty
For someone who only trains once a day like I have ever since I was at Gakushuin University, I feel that adding ultra long-distance jogging trail runs on my days off has been effective in improving my physical and mental ability to hold it together in the second half of the marathon. … in my case I’m typically averaging about 600 km a month.