A thought occurred to me the other day when I was discussing the time it takes the human body to adapt to a consistently introduced new stress with my coach. My understanding is that it takes the typical human body three to four weeks to adapt to such a stress, in this case an increase in base mileage.
So for example, let's take a hypothetical runner "Scott" with some running experience and well-developed, efficient form, but little formal training. His year-long plan would look something like this:
Weeks 1-5: 30 miles
Weeks 6-10: 36 miles
Weeks 11-15: 43 miles
Weeks 16-20: 50 miles
And so on, until...
Weeks 46-52: About 90 miles
Or up to whatever Scott's goal mileage level is. He then holds at that level for a few more weeks before starting speedwork.
Has anyone ever tried to apply this principle for an extending base period (probably of at least 9 months)? What were the results? Did you or your runner hit a wall in terms of mileage level reached without injury?
I don't really have much use for such a training tactic as I have two seasons of racing a year, I just think it's an interesting thought experiment. I'm especially curious about how well it would work with younger runners.
I guess my key question is, what is the actual amount of time it takes to adjust to a mileage load?