My back continues to hurt. I think it's gotten better, but not good enough to safely ride outdoors. So, I decided to do an indoor training ride on Zwift. The first half of the ride was mostly modest tempo. I was being passed left and right. I did the London loop. I wasn't sure how to ride other routes. More investigating on that later. My legs felt good. Obviously, my (lower left) back was the weakest link. It limited the amount of time I could stand on the pedals. Suffice it to say, I stood up only on the steeper portions of the ride. I was approaching my usual tempo on the last 15 minutes or so. I was able to put in a sprint over the last kicker. Gear is working well. I had no serious problems today. Although, the simulator tends to flicker here and there. Not was much as the previous time. It's intermittent and last about the same time it takes to blink your eyes. Noticeable, annoying, but not a game breaker. There were 800+ riders today. I think I finished around 80 something. So, overall, I felt good despite my lower back issue. I was able to push it into the upper 130 BPM's. No other ailments noted. I think I got the settings on Zwift in lock-down. It worked without fiddling around. The cadence sensor was the last thing to be recognized. A few turn of the pedals fixed that problem.