Why do it?
To slow aging.
What is effective muscle building after 50?
It is you proactively taking control and not just letting the effects of declining strength control your outcome.
From this study:
Do the opposite.
Yea. Want to know how to build muscle at 50?
Watch the old guys training in your gym and do the opposite. See the guy walking on the treadmill? Don’t do that. Go lift some weights.