Posted: Yesterday at 09:50
1) what do you think are you recovery, easy, tempo and speedwork paces.?
2) what proportion of your training running fell into each of the above buckets?
Reson being your 5k and half marathon PBs are consistent with those of a well trained 3:15 marathoner. However it is possible that they are being run with a heavy reliance on your anerobic system and glucose metabolism. Marathon running on the other hand will burn through all your carbs unless its done in a much more efficient aerobic way and (this is debated) metabolising a different fat/carbs mix along the way.
Long story short - if your aerobic base isnt up to the job, there will be nowhere to hide over 26.2 miles and the wheels will come off. You might get away with it and gut your way thorugh a fast 10k or even half, getting nods from the GFA marathoners around you. Then totally fail on race day becaue you havent trained the right systems in your own body for that distance.