Is there a limit to the human body in the mile.?

"Because of the new healthcare and society, in America and other deveoped nations, it is not mandatory for poeple to be skinny and fit for them to survive. Because of that, there is no specific reason beyond random chance that humans will develop into faster milers."

I agree that it has been centuries since "some" cultures needed running ability for survival but you can look at native Americans up to at least the 1700's and running was a necessary part of their culture.

So the gene pool of natural running traits would seem to shrink. But the concentration of those with positive traits are still high. There are a lot of factors that increase the likelyhood that two runners with superior genes would couple.

1. They are brought to the same place on a regular basis due to financial and psychological motivations. "Races are the watering hole of runners"

2. The act of long distance running reduces the ability to mask the smells that inervate our baser drives.

3. After-race parties are well known incubators for reduced inhibition.

4. The fact that good runners are extremely thin and don't earn wads of money make them less attractive to large segments of society, esp. breeders carrying those superficial aesthetically pleasing genes.

I'm also interested in how someone feels the answer to running would be the recruitment of more muscle cells at the same time. Do they want a longer, more explosive stride? If Max VO2 is the limiting factor it might be a more efficient use - maybe fewer cells to do more of the work. For example, a lot of muscles during running are just used for balance and stabalization. Maybe that is a reason why there are fewer taller runners. More skeletal muscles are needed to keep they erect, ie depletion of a finite resource - O2