Although the crowd was small- there were only five of us- the ride to breakfast was fine. The weather wasn't even too bad despite the cold temperatures; I think all of us were properly attired. Breakfast was fine. I rode with the group back to where they get on the trail and instead of riding back to the starting point with them I set off on my own to ride home.
The first couple miles were fine, but then my left knee started to hurt. No biggie, I thought, I've felt a little pain in my knees before and just rode through it. But this time it got worse and worse and worse. I actually had to stop a few times to get off the bike; at that point I was having muscle spasms in my leg. The up-hills were the worst. I considered calling the wife and sagging home, but pressed on.
Then the achy knee started to get downright painful. When I rested the knee it was hard to put weight on it. Still, I thought I could make it home. I was getting close- about a mile out- and then it happened: the rear tire went flat. I noticed it in the median of of a road.
From there I just got off the *@$##& bike and walked the rest of the way home, knee hurting, rim bouncing on every little bump.
I made it home in one piece. I popped some Advil and crashed for a couple hours. The knee's been sore but not very painful after that. Since I'm transitioning job sites and going back and forth, I'm not bicycle commuting right now. Hopefully the rest will let the knee heal.
I think the cause might be some adjustments I made to the bike; I think I may have been hyper-extending the knee on the downstroke. So I lowered my seat a little bit but I still haven't fixed the flat. Maybe over the holidays I'll feel like dealing with it.