I'm 59. Had 9 surgeries. 3 weeks since my laminectomy, 13 months since my cervical fusion. 8 months since I blew out my ACL. Need a knee replacement.
Until I blew the disk out which caused this recent surgery I was still pretty strong and explosive. Despite being a little too heavy.
I ride with the bike club and can still hit 53 mph plus on the downhill and almost 40 mph on the flat. If my back hadn't gone I think I'd be over the top. I was pushing 1700 watts.
I am not sure if I will have anything when I come back due to the nerve damage. That seems to be the limitation.
I hammered myself racing - Jumps,to 400 m runner, lots of work. Early surgery from a traffic accident forced me to sprints. So I have a lot of history of injury which I ran through. I doubt your issues are similar, but I think I mine are extreme.
I have found that as you get older you really have to manage your rest. I suspect that you need to take more off days than you believed, and focus on freshness. You should also try to make sure things you took for granted are managed. Like your core strength, and keeping the weight off. Added weight is a killer for old runners. Everything blows up. Ankles, knees, feet, neck, back. All due to too much load.
Take up flower arrangements on the off days. Stay away from the Hard Work.
Paula Newbury Fraser was top Tri lady who came back when she was really old and did almost as well, and on half the work. She said rest and recovery was the most important thing to an athlete as they get older. I am not talking 35 year olds. But 45 plus.
Soreness used to be a badge of courage for me. Now its something I try to manage.