The problem was different this time.
After finishing the run on September 20th my left leg felt sore but I incorrectly surmised it was my shin again. However, while it was a little tender, that was not the issue. Rather, it’s the ankle, which is new. I can still feel it some 12 days later, so I’m not going to be running again for at least a few more weeks. I’ve read that there is a small chance that regular running on a track or oval can lead to each leg getting a slightly different workout and can increase the risk of injury. I wonder if that’s what has happened here. When I do resume running, I am going to try switching direction every other time, so I run counter-clockwise one day then clockwise the next. I may also plan out my first runs away from the park.
Next week, with the ankle feeling better, I’m going to resume my free weights workout in the interim, so all of my other muscles can be sore and share in the fun, too.