Wow!...those are impressive race times! Was your weight around 170 or so when you ran those times especially the track mile & the 19:13 5K? Btw, you got me on the weight this week as I'm holding steady at 170 on my short 5-6 frame (down considerbly from my college football & powerlifting days decades ago where I weighed a porky 190 lbs. Lol).
And looking at the snapshot of your year-end race review, those are almost identical times I ran in the mile, 5K & 10K back in my early 40s - some 17 yrs ago! Presently, I would need to add 4 minutes on average for the 5K, and I'm hitting right around a slow 7:25 or so for my weekly "just for fun" track mile TT (just me, myself & the wind. Lol). Again - impressive times for a bigger runner at your age, IMO.
As I mentioned before, your weekly training for that block is almost identical to my weekly training throughout the year. However, I go 12-13 miles spread out over 3 days (at your 9:50+ pace) with Sunday's 4 miler finishing off with a track mile TT. Anymore than that in either volume or intensity, and my chronic injuries & OA rebel and show no mercy. Lol. No your limits is my motto nowadays. Interestingly, I'm doing exactly the same spinning sessions both in duration and cadence that you do, except I spin at the local 24 hr fitness on the four days that I don't run - plus lots of strength training & rehab excercises - which is keeping running though probably on barrowed time.
Curious: What's the diagnosis of your knee injury? My primary injury from MRI imaging is a completely ruptured PTT (and a secondary finding of OA) of my ankle (compliments of trying to outkick a young buck on an uphill finish at a 5K several years ago. Lol). Over the years, and only after turning 50, I've also sustained a grade-2 Achilles tear, patellar tendinitis, and a recent finding of some hip OA (plus a bad back from a MV accident). This is where regular icing & acetaminophen become your best friends. Lol.
Years ago I was having trouble with my knee (opposite leg from the ruptured ankle) in terms of post-running soreness and the joint giving out when pivoting or changing directions - definitely some stability issues. Got another MRI with a finding of a degenerative ACL tear but otherwise a good articular cartilage and stable LCL, MCL, & PCL ligaments. I figured the ACL may have been from a few knee sprains back in my college football days, but interestingly the MSK radiologist I chatted with said degenerative ACL tears are a pretty common finding with a lot of avid runners over age 50. Normally they're asymptomatic or cause generally minor problems. But they can lead to the dreaded OA over time particularly with the mechanical stresses placed on the knee from a high-impact activity like running.