It's like a marathon that gets easier as you go on. Marathons actually get a lot harder as you go on. Miles 0-16 are no different from regular short runs, 17-2

It's like a marathon that gets easier as you go on. Marathons actually get a lot harder as you go on. Miles 0-16 are no different from regular short runs, 17-20 is hard and you start to flag, 21-24 is brutally difficult, and 24-26.2 is easier for psychological reasons.