Marathon Pacing Strategy

taking lead from a comment from Rick to my previous post, I would to list some personal guidelines of mine:

- after many observations, I think that negative split is possible and definitely the best strategy for a marathon in the 2h20'-3h00' hrs range (for people targeting 4hrs of so, the situation might be different because it is a much longer time on your feet so also peripheral fatigue might be of stronger influence).
If you target to reach the 25k mark with something in the tank, then it is "only" 1 hours of effort left (more or less).
All the stories about glycogen exhaustion and so on really give solid base to run a first half in more moderate effort and then give it all...

- my personal preference is to run always with HRM so that I can start the marathon with the first 5k at 80% HRmax and then gradually build up to 85% after 15k to keep until when you must forget about the HR and just push harder to keep the pace.
Usually the recommended average HR for a marathon is around 85% HRmax. But if you start straight at 85%, then it become unsustainable after 25-30k and eventually you will lose speed and also the HR will drop (for exhaustion of glycogen reserves).
If starting at a more moderate pace/effort (85%) the HR can gradually rise and keep on rising for all the race even reaching 10K effort level (90-92% of the max).

Better than whatever I could say, I found this GREAT pace calculator for the marathon
http://feelrace.com/marathonperfekt.html


It is 99% the same principle as I would follow and gives you both the progression of pace and HR to follow... amazing online resource