Three miles into the run, I stopped to stretch because my SI joint on the right side was acting up just a little bit. In the process of leaning over and stretching, with my right stretched out onto a fire hydrant, I suddenly felt a very strange sensation on the left side of my lower back, like muscles that shouldn't be touching one another were suddenly best buddies. I knew this was not good. When I put my foot back on the ground and tried to stand up straight, I couldn't. I tried again, and with real effort, stood up straight. Ok, I'll just stretch it out a little, right? Nope. I hobbled three miles home, knowing I wouldn't be running for a few days. | 