A person in the know told me I should back off the mileage a bit and save it for when I get closer to a marathon. I ran 18 miles last week Sunday and wasn't looking forward to doing 20 this coming weekend. I don't want to injur my knee. I'm thinking about running the Portland marathon in the fall. Someone I run with spent over 8 hours this past Saturday running on the trails outside of Leavenworth, at times through hip-deep snow, for 22 miles ... and he considers himself an average runner.