For a few years now I have had what I believe is patellar tendonitis. The symptoms are weakness and pain below the knee cap when I run longer distances, say more than five miles. The farther I go, the more it hurts. It prevents me from running fast on downhills, which is bad (especially when your not particularly fast on the uphills).
I haven't done anything about it because it goes away quickly. It doesn't bother me when I walk, and it usually doesn't effect future runs after a day or two. But now I want to do the Grand Traverse this fall in Duluth. At least the 20, and 27 sounds like "fun". But I have to get past the tendonitis to train properly and complete 20+ miles on the Duluth hills.
Starting to look at necessary strengthening exercises now:
https://runnersconnect.net/running-injury-preventi...