2019 Colfax Half Marathon

A mile-high sub-1:30 (despite making some mistakes)!

May 19, 2019 (updated May 19, 2019)Filed under blog#fitness#runningMarkdown source

Assumed audience: people into the details of endurance running and races. (Yes, I know that’s probably a vanishingly small part of my normal readership. That’s just fine.)

Today I ran the half marathon event in the Colfax Marathon. You can see the details here (I prefer Strava’s presentation, but you have to have an account to see most of it.) I finished at 1:29:56 wall time, and 1:29:50 chip time. (The difference is because I started at the back of the first corral instead of the front and had to wait for a few dozen people to get moving in front of me.)

I am exceedingly pleased with this outcome. It would have gone better had I followed my race plan and not pushed so hard on the climbs—and the fact that I am still a bit sick I noticed throughout. Still: I could not be happier with my first race at altitude.

  • 58th overall, out of 4617 = top 1.25%
  • 48th among men, out of 1830 = top 2.7%
  • 19th among 30–39-year-olds, out of 671 = top 2.9%

This is particularly happy because it’s coming on only about 3 months of active training. That bodes well for future efforts with more miles under my feet!


Somewhat more details observations on the race:

  1. I went out too fast. I felt really good at first, and paid for it at the end. This is not new to me; I’ve done it in most races. Over the summer, I need to actively practice doing negative splits on tempo runs—and I need to do that with both downhills and uphills… see the next point! I also need to practice hitting specific tempos so I can do a better job holding myself to a given speed at a given time.

  2. Hills, even little ones like this, still just murder my legs’ ability to keep spinning. Especially given the profile of my next race (it has literally 4× as much climb as today’s race did, and it starts ~1,800 feet higher), I need to spend some time this summer doing two things (in addition to continuing strength training and the point noted in #1):

    1. Cycling! That should be a really helpful complement and strengthen exactly the muscles I need.
    2. Speed work! Now that I have a really solid aerobic base again, I need to start amping up my anaerobic capacity in kind.
  3. Not being sick would also help. Not that I can perfectly control that, of course, but I could feel the effect that had in terms of general physical fatigue and getting light-headed and a rather unhappy headache for the last five miles or so.

  4. Bringing my own water is essential. I can never hydrate well enough with cups along the way. Best bet is probably a belt: I don’t need a lot, but more than I had today. I hydrated reasonably well ahead of the race, but I do not doubt this contributed to the headache and light-headedness. (I know they were at least partially from being sick, though, because I had those symptoms all week.)

  5. Next time I run a race, I want to actually plan out a specific tempo and effort level on a per-mile basis, and see how that works. I suspect it will help. The main possible downside I see is that I might under-do it going at it that way, but if I end up having a lot of juice left I can probably make up a fair bit of that just by crushing the final 5k.

All of those thoughts on what I do next notwithstanding, I remain really happy with this outcome, and I am glad to be getting back into the swing of things.

One final note: the best data I can find online suggests that 5,000 feet of altitude is worth ~15–20 seconds/mile at this distance; that would make this race very close to my best. I suspect I would have run the same course at sea level somewhat faster… but not 15–20s/mi faster. Why? See #1 and #2 above: the real problem was that I went out too fast and didn’t have enough leg strength left over at the end, not that I didn’t have the aerobic or anaerobic capacity. (Looking at the heart rate data from the race confirms this, and I noticed it even during the run: my problem the last few miles was leg endurance; my HR was actually dropping in miles 10–13.)