My 4th London Marathon (92,93,94 & 04). Previous PB was 3.18, trained hard for 3.15. Did four 20-21 mile training runs. The 21 milers were 2.30 to 2.35 with no stops, so I was in good shape for 3.15. Had a slight muscle strain three weeks out, so hardly ran during 'taper time.'
The start was even slower than I expected (mile 1 in 9 mins in spite of being in Pen 2) and I was 2 mins behind schedule at 4 miles. Then fell into a better pace and should have been able to bang out mile after mile at 7/7.15 pace. By halfway I was just inside my target but it felt too hard. It all fell apart @ 19-21. Had to stop and got cramp - never had that before. In the end 3.35, my worst result.
So where did I go wrong and how do I improve? I'd done the training, I'd taken on liquid, I had my jelly babies etc etc.
Should I have continued 'slowly' ie outside my target time, trusting that I could then run the whole way thereby eventually acheiving 3.15? That would effectively mean running a negative split which I really don't think I could do in a Marathon. My training runs were 7/7.15 pace from start to finish. How do you train for the fact that on the day it is not like that?
Advice greatly appreciated,