Really interesting thing I came across:
When you think of the greats of our sport, you really come across 4 distinct eras in the 10k. Cheptegei, Farah, Bekele, Gebreselassie. These four have had their own share of dominating the event. You'd think that Bekele is much older than Farah. But, in reality, Bekele is only 1 year older.
Despite the closeness in age, we never really saw a true prime Bekele v prime Farah on the track in a championship. In championship races won by Bekele, Farah never was better than 6th (2007 5000m). In championship races won by Farah, Bekele DNFed (2011 10k) and was 4th (2012 10k). The 2012 10k is the closest we get, but it's hard to argue that was prime Bekele; he hadn't won a title since 2009 at the time.
I highly doubt age cheating comes into the equation for Bekele or Farah. Bekele is still out here at an Olympic-level in the marathon at age 42. I doubt there was ever lies about his age, or we'd be seeing a man qualifying for a top tier distance team in his high 40s. Farah was also quite an outlier for dominating the 10k in his 30s; I also doubt he was much older.
Bekele won titles from ages 21-27, Geb won titles from 20-27 and Cheptegei has won titles from 23-27. Farah is the outlier, winning titles from ages 28-34.
Why was Farah's peak so late compared to the other greats of the 10k?