My wakeup heart rate was 52 this morning. I had a good energy level, and I looked forward to my run. After my walking warmup, I started the run shortly after 12:oo noon. The sky was sunny, the high temperature was expected to be in the low 40s (F), and itr was a beautiful day for running.
After I had run about a third of a mile, I felt what I thought was a cramp coming in the hamstring of my right leg. I immediately stopped running, and about two seconds after I stopped, the cramp hit. I felt the muscle that was cramping, and it was very hard. I stretched my hams for a few seconds while massaging the muscle. The muscle felt better, and I started running. I could tell the cramp was still there, and I stopped and repeated the stretching and massaging. I again started running and stopped within a few steps due to the cramp.
My leg felt OK when walking, so I walked to the end of the new north path and back to the parking lot (1.5 miles total), all the time massaging the muscle. The massaging didn't reduce the hardness of the muscle, so I aborted my run and went home.
Later: The condition in my leg is more serious than I had realized. My leg feels fine while I'm sitting, but if I walk, both of my legs tighten up and I can feel the "cramp" in my right leg, and I have a very low energy level. Climbing the stairs to my bedroom to take an afternoon nap was painful in my right leg.
This is really a strange situation. I felt great in the morning before my run, but after a third of a mile, I didn't feel good at all.