Here is a graph of pace vs miles with both CIM and the Eugene marathon data on it the data has been smoothed a bit:
CIM is in blue..you can see that I was holding a magical 9:00 /mile with some slowdowns here and there until my kick at mile 21-ish.
Eugene, on the other hand shows a consistently faster pace with the war of attrition against fade starting at about mile 16...the pace slowed from about 8.50m/m to 9:16 m/m and then for the last 1.2 miles I was able to reverse the slide (the end was in sight!).
Now, look at the numbers on the title line: the average HR is higher for Eugene by about 3 bpm. The pace is of course 3 secs/mile faster (these are garmin paces so add 3-4 secs per mile to them). The efficiency in yards per beat of heart is about 2% better for CIM.
Both races have about 350 feet of uphills but CIM has an extra 350' or so of downhill. The equations say (check out my fav running calculator link below) that CIM is about 2 min faster at my paces.
Basically, my fitness for both cycles was pretty close but I ran faster this time with no downhill and with slightly higher temps.
I think if I had been able to run a CIM course in perfect weather at my current level of training I would have maybe been able to eek out a 3:53.
I have only been doing proper marathon training for two 400 mile cycles. I'm a lot stronger now and could probably take a bit more. What happens if I add lots of cross training (biking and swimming)?
My ergonomics are cleaned up a lot since I started. Yesterday was DOMS day and I had not much soreness at all after the fastest race of my life. I was able to go up and downstairs with no problems at all!
After CIM my AT was so bad it was a week until I could walk normally. This time it's only 3 days and I feel like I could go for a slow run no problem (I'm not though). I have some upper hamstring soreness (less than in training!) and some upper calf soreness (where the spasms were during the race).
So things are quite different now.
So this begs the question, what is the limit? Lose 5 lbs, have a perfect length training cycle with no bobbles could we get down another 10s / mile? maybe even sub 3:50?