For the last two weekends, I’ve tried to run 10k for my “long” run of the week. Both times, I got about half way done and had to stop and just walk till the end.
After researching it, I don’t know if it’s my knee or my calf muscles, but both times it occurred I was doing uphill running. So I have gone flat, and back to intervals. Today I ran 10k on an indoor track, walking 200m and running either 400m or 600m, then repeating. And it was pain free.
So somewhere in the (a) softer track, (b) flat surface, and (c) pacing myself, is the solution. Now I’m going to find a flat outdoor run for sometime over the Thanksgiving weekend, and pace myself the same to see if I can do as well on asphalt as I can do inside.