So, I'm doing some base training (about 80mpw, strides 2x a week, tempo, fartlek, long run, easy runs at 6:45-7 15:30 5k pr) and having a problem where I just become increasingly tight toward the end of my easy runs. Like I'll start a little tight, get looser, but then the tightness just ratchets back up. Usually ending runs tighter than when I started.
What's the LR diagnosis here?