A Runner's Personality

Could it be that you need me
To keep you out, to run you faster
Promise me you'll let me be
The one, the worst of all your enemies
Pretending you're a friend to me
Say that we'll be nemeses 

While sitting in the lab listening to Jonathan Coulton's new album, I found myself humming the chorus to Nemeses over and over. Then I began to think about the lyrics one day on a run... sure, sometimes trying to set a PR is motivation enough for me, but I think most of us can relate to this:

So, what is it? I mean, I wouldn't describe myself as an overly competitive person... but if someone gives me the one-over at the start or does a double-take and then speeds up to stay ahead of me on a training run, suddenly it's on. I mean, I've run hard at the end of a race when I'm close to hitting a PR... but this does not compare to the sprint that will ensue if someone wearing a running skort or basketball shorts (hey, we all have our limits) tries to pass me in the last 1/4-mile. And, have I ever mentioned that the whole reason I started racing again was because I got mad when I saw that someone I went to college with (who hadn't run back then) ran a half marathon?!

On an intellectual level, this makes no sense. So, this got me thinking... why do I? Which got me thinking... do runners share a common personality trait that this can be traced back to? So, I looked it up, and came across this study- competitive cyclists scored lower than the population average on tension, depression, anger, fatigue, and confusion, and above the population average on vigor. To my surprise, I also found that a lot had Type-A tendencies. And, I came across this LetsRun thread, which was a little less than complimentary!