I should start with targets, because they matter much more than the history. 

First, my current goal: run Boston Marathon in 3h25'. Then I want to run some trail 50 miles or longer ultras with a good pace. Recently, on October 12-th 2013, I ran the Baltimore Marathon in 3h34'44". It's approximately 5 minutes better than my a year-old results of the same marathon. But I was trying to get it in 3h25', and until mile 16 it looked very achievable. On mile 16 my hamstrings started cramping.…