Say if I ran a 2:55 in the thon as a result of some ok high mileage training (70, 80+ miles per week), and if I kept training this way for a year, then for 5 years straight, how much would someone who's in their late 30's progress?
Would 5 minutes per year be reasonable? Or would it be closer to 10 minutes?
Similarly, how much would someone progress given the same training and the 2:55 starting point, if they were in their late 20's? Late 40's?