After the pain I felt in my foot while running (or bouldering or sometimes just walking) didn't lessen after a couple of weeks, I decided to actually get it checked out by a doctor. The verdict? A stress fracture in my third metatarsal.
I've been given this big boot to wear and told not to run or climb for the next six weeks. The boot is pretty much the same one I wore when I broke my calcaneus (on the same foot) a few years ago, which seems weird because this is so much less of an injury. At least I'm not on crutches for this one. I have a suspicion I mostly have to wear it because the doctor (who was great, by the way) wants me to actually take the no running or climbing thing seriously. Which is hard. But, as she pointed out, it's a small fracture now but I have the potential to make it much worse if I keep doing what I've been doing.
The real kicker is that it means I won't be able to run either the Boston or the Big Sur marathons that I had been training for. And they're making it harder to qualify for Boston after this year, so I'll have to up my game if I want to run it a future year. Or try to qualify at an easier race; I qualified at Big Sur last year, which is notoriously hilly.
As much as I like the concept of this new trend of barefoot running, the doctor said she thought running in my barefoot shoes is probably what did me in. Apparently I'm a supinator, the opposite of a pronator. I have high, inflexible arches that don't do as great of a job absorbing shock as I run, making me more prone to things like stress fractures if I don't have sufficient padding.
I guess I'll have to be a little more sedentary this next few weeks. Or become more aquatic; floating shouldn't further stress out my feet.