Inside look: Joyciline Jepkosgei’s training ahead of half marathon world record finish
Nothing, I suspect, that will surprise you too much. A twitter thread by a couple people who would know say this is pretty much what everyone does in Iten. The difference, it is suggested, between it and "western training" is using the long run as a harder session, rather than accumulating extended time on feet for its own sake, and keeping in touch with faster stuff--even track work--while training for longer races. To be fair, I think that idea has infiltrated training thought on this continent to a significant degree. Even mainstream online calculators suggest a long run pace that's a little faster than your easy pace, these days, regardless of target distance, and significant work at marathon or half pace is par for many courses.