Nigel wrote:
In the book Daniels' Running Formula, Jack Daniels says we are limited to approximately 20%-25% improvement from training. He's talking about V02 max, but because V02 is related to actual running speed, it comes to almost the same thing.
Imagine a young, healthy, non-running but active 18 year old. He goes down to the track, sees some guys doing interval miles and joins them for the last one. He runs his heart out and clocks 5mins flat. Daniels is saying that with a couple of years of training, he could become a 4 minute miler. Of course, if his pre-training best was 6 minutes, his potential best would be about 4min50.
Bekele has run 12min37 for 5k. That's 14.7mph and it's 23% faster than the 12mph he needs to have run 15min30 before starting training. Sounds about right to me.
Jim Ryun ran a 5:38 for his first mile, and he got a 3:55 in high school.
I don't know much about Bekele's early childhood, but he could be a big responder like Ryun. In that case, Bekele wouldn't be able to run a sub 15:30 off of 5 miles/week.