Ummmm...Well I am close to the second example, LOL! I am not yet allowed (again) to train with weights. The last time I could do squats was well over a decade ago and I was even then, older than he is now. I did multiple sets of 20 reps with 300lbs to 400lbs. I used stands made by my late brother and a pair of sawhorses in the event I could not complete a rep. My best leg extension at home was 225lbs. for one set of 100 reps. That was hard, almost as hard as my 100 rep squat with 225lbs in the mid '80s. I was shaking on that one, LOL!
Those days are long gone and yes, I have difficulty with but continue to accept that reality, but as Lone Watie would say, I endeavor to persevere! 
rightfully so, you shouldn't be doing the same shit you did at 19 when you're 50, your training should evolve as your life does. The training should enhance your life,
if you dont you end up in a wheelchair or a functional cripple like bhanks is. You've already mastered the barbell, how many ppl in the history of the world could say the did 400 for 20? why continue to try to emulate old glory days.. make new ones. I would imagine for most us here movement and strength sports is a bit of a passion,move on to the next thing. Rock climbing, trail running, calisthenics, grapple, get a cheap spud harness and pull your car around your neighborhood shirtless for the ladies to mire(if you have a kid have the steer and marvel at how rad their dad is). there's so much you can do and it can be fun as hell.