5.25 km, 3.25 miles (approximate).
This one started out so promising. I stretched my calves really well and was clipping along without my watch telling me I was too slow - in fact it told me I was too fast a few time!
But 3k in my calves were on fire and I had to stop and stretch. Went again, no go. So I walked (and walked) until I was on this gorgeous flat stretch of dirt path, the kind where the trees make a tunnel. So I ran again, and focused on my form, tried to engage my glutes and pick up my knees. I saw a tik tok about running form and it said to focus on "driving your knees upward".
And it worked. My calves were totally fine. But it also sped me up. Enough that my heart rate was quite high. But I gutted through the heart rate (it was surprisingly hard to slow down while "driving my knees upward") and finished the run and my calves were fine.
So, apparently when I'm super slow like now, I'm a shuffler, and the shuffling is destroying my calves. So in the end it was a good run despite the very annoying middle piece.