from the NN London preview, Bekele claimed he never prepared well for his track records(@ 6:40 in video below) and could have gone better (although I'm sure we all think that about our PRs). I think this corresponds to what Canova has stated that he never even trained for 10,000m but just did it as part of his 5,000m training.
https://www.youtube.com/watch?v=-yEszvMC8Go
All, hindsight, but think he could have actually gone better than his 12:37 and 26:17?