Running metric

It's been in the back of my mind for some time now; I've been vaguely aware of its general consistency. In most races, my finishing position percentiles have seemed to be fairly close to each other, whether relative to the entire race field, men only, or my age group. The pattern has seemed to persist, regardless of the type of race or size of field. Curiosity piqued, I went through my race results and did some quick spreadsheet work (See plot). The x-axis is my finishing positions, and the y-axis is the total number of runners, whether of the

entire field, men only, or my age group. The blue trend line, with an R-sq = 0.6577, suggests that the size of a race field (all groupings, all types of races) is a fair indicator of my finishing position. This result also suggests that the population distribution of race paces is fairly consistent, at least for the same geographical region in which most of the races took place, and reflects the consistency of my pace across races. There are some uncertainties in my statistics here. For example, I mixed the results based on the entire field, men only, and age group. Also, for some of the larger races that had fields in the 10s of thousands, I scaled the results to be less than a thousand, to fit in the plot.

In any case, what's of more interest to me are the red, dashed lines, which are the 50th to 90th percentiles. So, if my result fell on the 50th percentile, then 50% of the field crossed the finish line after I did. The blue trend line is just above the 50th percentile, which accords with my general vague sense, over the years, that I usually finish near the bottom of the top half of the field. But, as the data show, there are also some outliers that are of higher percentiles (a few near the 90th--must have been relatively slow fields!). This is interesting because I can use the location of the trend line relative to the percentiles as a metric for my running progress. I'd be interested to know what you use as metrics.

GPS watch - unfair advantage?

I've heard about the central governor theory of fatigue before, but it was coming across it in Scott Jurek's book, Eat & Run, that got me googling for more. There are tons of writings on this topic, pros and cons. As I read up more on this, I'll come back to it in future updates. For now, I'm going to just use, as a working definition of central governor, that from Wikipedia: "a proposed process in the brain that regulates exercise in regard to a neurally calculated safe exertion by the body. In particular, physical activity is controlled so that its intensity cannot threaten the body's homeostasis by causing anoxia damage to the heart." This control is experienced as fatigue. First suggested by A.V. Hill in the mid-1920s, this theory has been more recently proposed by Tim Noakes of the University of Cape Town, South Africa as the Hill/Noakes Central Governor Model. In Jurek's book, he told the story about his friend Brian Morrison, for whom he paced in the 2006 Western States 100. Morrison, who was leading the race by more than 10 minutes, going into the Placerville High School track in Auburn, CA, just 300 yards from the finish, collapsed and couldn't finish on his own. His body apparently just "shut down." There are many other similar stories in marathon races. As runners, we all are aware of the mental aspect of running. We all run races faster than we train. We all run the last stretch to the finish faster, even though we felt spent just before. And, as I recently found out, I ran faster longer on a training run, when paced by someone else.

What does all this have to do with a GPS watch? Well, if the central governor theory is correct, then knowing exactly how much distance is left, in the race or in any particular stretch (such as to the next aid station), allows a runner to calibrate and thus run closer to one's physiological potential. And, with a GPS watch, one knows exactly (almost). I found this out during my recent half marathon at Dances with Dirt - Devil's Lake, where I ran with my very basic GPS watch and found myself running faster in several "last stretches" to the aid stations. Unfair advantage?

My basic GPS watch, from Timex (one of many brands available).