I've not been able to do much due to asthma, especially with the recent wildfires. I did want to get posted what I'd like to be doing, which is training to race 800m. Ultras were where my knowledge broke down 15 years (!) ago, but going the opposite direction, things fall apart at the long sprints.
Stage 1 would be just running 4 miles per day easy in 30-35 minutes.
Stage 2 would be incorporating speed workouts, but done at 75% effort, which is about race pace for races 15-20 times as long (for example, if 800m pace is 100%, 75% is about 15K pace).
Stage 3 would be running at 100% every 5 days. That would give the following workouts:
NOTE THIS IS NOT A WEEK'S WORKOUTS.
M 4x200m, 4x100m @ 400m pace - 4 minute recoveries
T 4x400m @800m pace (full recovery)
W 8x600m at 5K pace (2:1 run:recovery)
Th 3x (3x300m @800m pace - 1 min.) - 10 min. between sets
F 20x100m @800m pace - 1 min recovery
Sa 800m time trial
S 3x(1200m @ 5k, 400m faster) 2:1 run:recovery
The best I could hope for, next year in my new age class would be about 2:35 for 800m. The state record for my age class is 2:23.