It is really perverse that runners like talking about their injuries and limitations.
I'm back up to my 50-mile weeks -- plus, despite what appears to be a IT-Band injury. The IT-Band is a group of tendons stretching from the knee to the hip. When they get irritated it is often very much like sciatica -- the leg acts like it isn't getting a proper electrical fire. And, at times it can be painful to the extent the leg won't bend. http://www.rice.edu/~jenky/sports/itband.v2.html. I experience it mainly on downhill runs. I'm forced to limit my runs to road work and I'm staying off the trails. But, I'm getting a huge amount of great, long, speedwork in -- particularly when I come across another runner. One of my favorite speedwork sites is a long frontage road along the I-5 freeway. During rush hour, I can beat the traffic from one exit to the other a mile away.
The IT-Band injury takes a whale of a long time to heal; it may never. I suspect I got it in my 100-mile run on my Hokas, and then aggravated it running the 50-miler a month later without proper medial support. I'd been feeling twinges for a year, however, not thinking anything.
As well, my kidney stones are really attacking me after each run. I've been putting off the surgery for three years; now, it is getting miserable. I'll run myself into a hospital if I keep putting in daily 15 miles runs with zero water.
The fun and joy of long running!