4.5% wrote:
I don't know if other people had similar experiences, but I ran in vaporflys yesterday and my quads were destroyed in the hills and I thought I was going to have to drop out around 18-19. Then as soon as I hit the flatness of the last 5 miles my legs felt fine. So I don't know how much vaporflys actually help on hills.
FWIW I ran Chicago in vaporflys 2 months ago and my legs felt amazing the whole race and I could definitely feel the (4%) difference from other racing flats.
you seem very undertrained for any sort of hills. the last 5 miles aren't significantly different from miles 13-21, and there is basically one hill (a bridge) after mile 13.
I'll add my name to the HUGE list of people who have run CIM and think it's a fair course if there's no tailwind.
I'm from Sacramento and am very familiar with the course. I've run it in '15, '16, and '17, though only really raced it in 2016 when I ran 2:32, my current PR. I have run no other "fast" marathons other than Boston this year to compare times with.
My thoughts echo what some others who ran have said. The course is fast, but the weather in the last 4 years has been incredible and the competition was top-notch for 2:13-2:25 guys and 2:40-2:50 women since it was made the US champs course. next year will not be a US champs but I think the reputation it's built will still draw out lots of fast runners next year, although most likely fewer guys under 2:16 and fewer women under 2:40.
the people saying that the net 320 feet of downhill trumps everything else are idiots. a race could climb 15000 feet and then drop 15320 feet and it's not going to be a fast course. now obviously there's a point of inflection where the amount of climbing equals out the net 320', and I really believe that it's close to what CIM has (680' up, 1000' down roughly). A couple years ago I made a thread offering a spreadsheet that I made to CIM hopefuls, with precise mile splits accounting for every hill of the course, for any goal time. I made this using Strava's formulas for calculating grade-adjusted pace. the result I got at the end of my calcs said that a 6:00/mi "effort" on the CIM course, with zero wind, would result in running 5:59.0-5:59.5/mi. So basically I believe that CIM is 13 to 26 seconds (for a 2:37 marathon) FASTER than a perfectly flat course. now, if you add in the fact that your quads get a little beat up from the early downhills (the same reason why Boston feels hard), it probably gets even closer to that perfectly flat course. The results from my analysis also showed that an even split is the best way to run CIM, or to at least be within 15 seconds of an even split.
one last thing - regarding the benefit of drafting. I believe that for a runner running 4:00 mile pace, you're supposed to run about a half second faster behind a rabbit (per 400m lap) than you would solo. so if you are in the OTQ group the entire way and never lead or fall behind too much, that adds up to about 100 seconds of aid at 4min pace, which due to physics would be a little less at 5:00/mi and even less the slower you go (not a linear impact, as it's based on V^2).