Well to your original question, yes run durability should be trainable.
I mean, your race result seems pretty solid; it seems like there isn’t a major issue in your training - solid run training, nutrition, etc. (assuming you did 90g carbs per hour on the bike, and not 90g total on the bike). It’s possible your overall training just needs something to level up - could be just compounding good training over another year or three, could be adding a bit of volume, could be changing up the intensity distribution a little (ex: sub in threshold and/or more tempo work for VO2, which may reduce your overall run intensity load, but be more 70.3 effort specific; or maybe some kind of progression run), could be adding in some of the strength training mentioned, could be reducing some life stress to improve recovery.
With the caveat of the idea that any measurement system isn’t totally applicable to an individual, let’s just look at your race from a Jack Daniels VDOT table perspective:
10K of 40’ = VDOT of 51.9
- Easy pace = 4:59 ~ 5:28/k
- Marathon pace = 4:23 (some say that a good 70.3 run is near one’s marathon pace)
- Took the liberty of looking at the tracker (not always accurate), you started near 4:30, ended around 5:10/k pace, for an average of near 4:45/k pace. That is sort of right in between that M pace and E pace from Jack Daniels, which in general is a reasonable spot for many people (Jack Daniels’ Marathon pace is more of an “ideal” pace given proper marathon training). Perhaps if you want to sustain that potential M pace you need slightly different, more specific run training.
Doing the same exercise with your open half of 1:31 = VDOT of 50.3
- Easy pace = 5:06 ~ 5:37
- Marathon pace = 4:30
- This half marathon time predicts a 10K time of 41:07, or just a bit slower than your recent PB. So your 40’ 10k could indicate you are a bit more optimized for that shorter, more intense effort, and little less optimized for these longer efforts (hence the durability question).
- I bet your Olympic/Standard distance would be quite good at the moment.
It’s possible your opening pace of near 4:30 might just have been a little hot (assuming that number is accurate, again I’m going off the tracker). I wonder how you might have felt starting at 4:50 or 4:45/k and holding it steady or potentially being able to increase the pace just slightly over the back half or the last 5k or so.
It’s also possible that temperature played a role too.
One other interesting resource on potential times: I like this thread from many years ago. The graphic seems to be gone, but I found another copy of it here. I believe I am attributing this table to the correct thread, and @Ale_Martinez, but not positive; also, the tri times are derived from original Jack Daniels VDOT tables. Anyways, your 1:40 is pretty spot on according to an open half time of 1:31. Your 40’ 10k time suggests potential of anywhere from 1:38 to 1:33 high, given the right training for you.
It seems like your efforts are worth applauding. It seems like a faster run is possible, but that getting to a lower run time might be a function of finding the right variable to change up. Good luck!
I would be quite interested to hear the thoughts of others. I find these types of threads some of the most interesting on slowtwitch.
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