Yeah exactly. Continuing to use your muscles so they don’t deteriorate, sleeping a good amount, and eating a decent diet that includes enough protein to sustain them.

You will still get less strong with age even if you do this but vast bulk of sarcopenia is just atrophy. Also worth noting that preservation is easier than gaining. Meaning if you get strong you can keep most of it with less effort than it took to acquire it.

The wikipedia has a good overview of factors and prevention https://en.wikipedia.org/wiki/Sarcopenia