I so much want to jump in here and defend the old guy (I'm an old guy). However, I can not find a single thing to defend. Just ramblings from a 'use to be' (I'm a use to be). I stopped lifting at age 72 after 60 years hoisting iron. 2 years now only 25 pushups in the morning and lots of mountain hiking. I at least look like an 'old guy' who 'use to be' a Bodybuilder.
I can tell you all about atrophy....but why bore you.
Being about your age (70 years old), I recently resumed exercising at the gym after and extended layoff for a variety of reasons including some health issues. I use the term exercising because what I am doing is a combination of cardio and weight training using relatively low weight resistance.
For example the first day back, when I did squats, I used just the bar, focusing instead on form and going really deep. After two weeks and 6 visits to the gym, I was using 35 lb. plates on each side for my final 10 rep set. On other movements the resistance is not much different than it was when I first started lifting as a kid. This feels really good and right for my body.
It's incredible to think it took me over 50 years to come to the realization that more is not always better. Bigger is sometimes just bigger and not healthier. In the past, I've massed up to 225 lbs. much of it muscle (I prefer to believe). These days, I weigh 185 lbs with a 32" waist. I have not taken other measurements because I don't care that much about arm or leg size as long as I look decent in clothes. Amazingly, the low resistance squats seem to be helping alleviate knee pain.
Vince can hold onto his dream of growing bigger arms against all odds. These are choices we make. I wish him every success in this endeavor because it seems to be what drives and inspires him to hit the gym. Me....I'm way past wanting to look like a superhero at all costs.