I never really thought about it, but I can tell you this much. I have boys that have run for the Dana Hills program in high school. They are both sprinters. The older one is running 400 in college, and the younger one is doing multiple sprint/relay events in high school.
Both kids have played soccer at lunch and basic stuff like that, but neither has run one step of "distance training," and frankly, neither would be caught dead running XC or 1600/3200. The only distance running at all that either did was running a mile once every week or two in PE. I think the younger one might have run 1.5 miles in PE once.
Off that "training" my older son ran about 5:50 in PE and my younger one ran something like 6:05 or 6:10. We didn't write the times down as we didn't find them remarkable. Plenty of other kids in their PE classes ran times like that. I congratulated them, and that was about it.
BTW, at Dana Hills, the qualifying time for 9th grade girls to run distance on the track team is 7:00. It is 6:00 for 9th grade boys. You don't make it onto the track team if you're a distance runner and you can't run that. Also, there are cuts in cross country.
Again, we never considered any of this remarkable. Those are just times that kids around here (Orange County, CA) normally run.