Can't remember where I read this but its good stuff
'Explaining young phenoms in our sport.
There are 5 major components involved:
1) Natural Talent
2) Anaerobic Development
3) Aerobic Development
4) Quality Coaching
5) Other (lifestyle, nutrition, habits, etc)
The current Junior systems in the U.S. and Britian (and many other countries as well) take athletes with #1 (Talent) and seek to quickly develop them with #2 (Anaerobic Development) and if #3 and # 4 are sufficient enough they have some early success (see your list of 15-16 yr old for 1500).
But the faster you get the more important it is to have all 5 things squared away.
From what I have seen the problem with the Junior systems is not with #1 or #2, we have plenty of #1 and know how to do #2. The problems with the Junior system is the lack of #3 at an early age, the lack of #4 to realize that #3 is lacking and #5 is lacking because of our modern lifestyle and the lack of discipline we show as a society.
I have seen #3, #4 and #5 kill off or stagnate countless talented American young phenoms.
Just having a deficieny in any 1 of those 5 areas can seriously set a young runner back, a deficieny in 2 makes it nearly impossible to make a world class level. But by having a lot of #1 and doing #2 you can show alot of promise early (and be proclaimed "The next big thing") only for your progress to be derailed by #3, #4 or #5. (Only 4 on your list make it to bette rthan 3:38)(po10 list)
There are those who have sufficient enough #1 that they can perform remarkably well despite weakness in other areas but they never make it all the way to the top.
Read this and think about it. Young phenoms and their parents, don't ignore any of these areas or be so blinded by your abundance of #1 and early success that you begin to believe that all 5 components don't apply to you and your ultimate success.'
Basically if you want some short term success, do lots of fast intervals. If you want long term success you want lots of aerobic work.