ilanarama: a mountain (mountain)
[personal profile] ilanarama
Apologies to my friends who read this for other topics (I will be doing a vacation road-trip in mid-December, and promise lots of photos of the Big Sur coast and Death Valley!) but this journal is pretty much all running all the time now, and it will be until CIM which is OMG JUST TWO WEEKS FROM TOMORROW!!!1!one!

Anyway, I mentioned a while back that I was thinking about the topic of racing weight. There's a discussion now (it's periodical, I think) on RWOL's Marathon forum. Conventional wisdom holds that weight loss is good for 2 seconds/mile/pound, assuming that it doesn't put you into dangerously underweight territory.

My problem is that I can't separate 'speed due to weight loss' from 'speed due to improved fitness', because the two are so closely related, at least for me. I tend to lose weight when I run a lot. Am I faster because I'm lighter, or because I've trained better?

Here's an interesting (and to me, telling) graph, pulled from my SportTracks log.

mpw and weight

This is my mileage (per week, running only) as solid bars, and my weight (average over the week - I weigh myself first thing in the morning most days, though not every day) as the triangle tabs, for the year. Last year, if you recall, I took off from late October through late November to raft the Grand Canyon; then I slowly built up my miles to the Canyonlands Half Marathon in mid-March. After that I ran just for fun and exercise, with time off here and there for mountain bike and raft trips, and then came our England trip with lots of hiking but very little running (and I didn't weigh myself, either, until I came back!). It wasn't until July that I really started building my mileage back up for my fall race season.

The correlation between weight and mpw isn't precise, but it's there. I think it's pretty obvious that the more I run, the less I weigh, although my weight range is fairly small overall. It's possible there is a signal of a brief increase in weight when I up my miles, followed by a drop - this might be from eating more before my hunger signals stabilize, but it also might be completely imaginary.

I don't 'diet' per se - I love food - but I cook most things from high-quality scratch ingredients. I drink more alcohol than I should, and also eat more sweets than I should - at least most of the sweets I eat are homemade cookies and cake! So pretty much all variation in my weight is due to physical activity (which includes things other than running, of course).

Talking about this with some runner friends (shout-out to my Women on the Move buddies!) it turns out that some people tend to lose weight when they run more, and others, to gain. (This is not counting people who "gain weight when they run" because they feel that a 2 mile jog justifies a 500-calorie 'energy shake'). Of course more running means you get hungrier, and eat more overall, but at least for me it's easier to maintain a caloric deficit through activity.

But I think that it might be related to body types in some way. At least in my quick and very nonscientific survey, the more traditionally female bodied types (hourglasses and pears) mostly gain weight when they run more, because they put on muscle. The more masculine skinny-muscled apple-shapes like me lose weight, because we lose fat. (My potbelly is much smaller now. Unfortunately, so are my breasts.)

I posted about weight shortly before running the Houston Marathon in January 2012; I'd gone on a short vacation to California around New Year's, and my weight had gone up due to eating more, but when I came back home and went back to my normal eating habits, it dropped right back down. I also posted a link (to an article which is no longer there, unfortunately) to a survey of elite and semi-elite runners, in which the average height for the women was 5'4" - my height - and the average weight was 112.4, which, I noted, I hadn't weighed since college...

...take a look at that graph again. Yep, I seem to be down to my college weight (early 1980s), more or less; I've actually been averaging about 112.6 but that's close enough. And it's kind of amazing, to me, since I have always regarded 114-116 as my 'racing weight', the lowest my body wants to be and still be healthy.

But I am pretty sure it's just due to how much I'm running. I've been averaging around 63mpw for the past three months. In contrast, when I ran Houston I averaged around 50mpw for the same period of time before the race. (And I weighed 116.6 just before going to Houston, and when I returned, so I assume I weighed about that for the race.)

I'm hoping I'll be able to keep my weight stable where it is for the next two weeks, so it will be this low for CIM. Unfortunately Thanksgiving falls smack dab in the middle of taper, so I will not only be running less I will be eating more, unless I can exercise more self-control than I normally have. But unless I entirely go nuts, I should weigh less at CIM than I ever have for a marathon. And unless I totally blow my race execution, or get sick or injured in the next two weeks (OH PLEASE NO) I should run my fastest marathon yet.

(no subject)

Date: 2013-11-24 02:11 am (UTC)
traveller42: (Default)
From: [personal profile] traveller42
If I read your chart correctly, there is less than 10 pounds variation in there. That says that the weight loss time signal is less than 9 minutes for the whole distance. I think you will have a hard time separating that from the improved fitness signal.

Good luck with the plan!

Also, I can't wait for the trip report (and the photos).

(no subject)

Date: 2013-11-24 07:44 am (UTC)
blnchflr: Running (running)
From: [personal profile] blnchflr
Have you done an actual correlational analysis, or are you just eyeballing it from the chart? I'm only asking, because I'm trying to learn statistics, and correlational analysis is sorta fun, and I'm trying to think whether one wouldn't want to correlate mileage one week with with weight the following, instead of the same week? And maybe crosscheck that with weight one week and mileage the next, which hopefully wouldn't show correlation?

But as for weight and performance, yes, it'd be hard to separate from improved fitness.

Interesting post - numbers <3

I would love to track my weight to try and correlate with mileage/performance, but that'd mean ACTUALLY for reals getting around to buying scales and figuring out where to store them in my tiny apartment, and I think I just can't be bothered by now…

(no subject)

Date: 2013-11-24 06:37 pm (UTC)
blnchflr: Captain America Civil War (Default)
From: [personal profile] blnchflr
Yes? I've been wanting to get around to trying cor an on numbers of my own, so maybe this will get me started :)

(no subject)

Date: 2013-11-25 12:30 am (UTC)
From: [identity profile]
Whether you can separate the effect or not, I'd think being lighter has to be a positive thing for running speed (up to the point that you wither away enough to lose strength).

I've only recently managed to get rid of my "trip weight"! I'll think twice before I pay for my meals in advance again. I bet if I'd had to fork out cash every night, I'd have eaten a lot fewer three-course meals!


ilanarama: me, The Other Half, Moab UT 2009 (Default)

August 2017

131415 16171819
20212223 242526

My running PRs:

5K: 21:03 (downhill) 21:43 (loop)
10K: 43:06 (downhill)
10M: 1:12:59
13.1M: 1:35:55
26.2M: 3:23:31

You can reach me by email at heyheyilana @


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