After about 18 months of running, at the end of last year I ran a 3:10 marathon off of 45-55 miles on 6 days a week (maxed out at 55 when my long run hit 20).
I want to break 3:00 at the same marathon this year (I am a chick)...do you think I can do it on the same mileage just by way of getting another year of running under my belt and more quality running, or do you think I need to bump my mileage? If so, how much?
No time to do doubles, so I have to stick to singles...
If you've only been running for 18 months, you may very well be able to improve 10 minutes on the same mileage and more quality, but I would recommend bumping mileage to 70 mpw. Particularly in light of your relatively low mileage, increasing mileage is the surest path toward major improvement in the marathon. Besides, it sounds as though you've got some talent. Might as well start to see how much.
I improved 50 mins over the space of 8 months and three marathons running slightly less mileage than you are doing.
My advice.
Add some longish repeats.
Start with 5x600
over the weeks increase to 6x1600.
Do them hard.
I have increased mileage in subsequent marathons and dropped the repeats. My times have suffered.
You learn by your mistakes.
Enough mileage wrote:
I improved 50 mins over the space of 8 months and three marathons running slightly less mileage than you are doing.
Obviously, some important details are missing from this history.
There are certainly some people who respond to the stimulus of higher mileage less than others do. There are also some who break down on higher mileage, but can handle higher intensity. I'm convinced, though, that for most marathoners, higher training volume (mileage) is the surest way to imoprove, especially if they're currently in the range of 50 mpw.