Running a Sub-3 marathon is a key landmark for any club runner, and a huge stretch for most of us mere mortals. To put Sub-3 into perspective, the mean time for all runners at the recent London Marathon was 4:30.45. Running 2:59.59 or quicker would put you in the top 5% of the field! I never considered myself an endurance athlete, and the thought of running 26.2 miles would have historically filled me with dread. Even worse, I would...