From Amby Burfoot's most recent column.
https://www.podiumrunner.com/culture/run-long-run-healthy-weekly-roundup-february-10-2022/
How Kenyan runners train
Kenyan distance runners train hard and race fast. We all know that. Apparently, they also have a high incidence of Achilles tendon injury—13.9%. I was more interested in the training data since we rarely see hard data of this sort from Kenya. Runners “in high altitude training camps” ran an average of 170 km/week (about 106 miles). They had an average pace of 8:07 per mile, which means the men likely ran at about 7:40 pace and the women at 8:30 pace. That’s at altitude of course, but amazingly slower than their race paces. More at African J for Physical Activity & Health Sciences.