Comment by machomaster

Muscle memory is a real thing.

Gaining it is hard and slow, but once you do it, you can easily maintain it with very low volume (1 time a week with very reduced volume/weights). And even if you don't train for years/decades, you still rapidly get it back once you start again.

That's why one of the best investments in people health should be weight training during the teenage years/20s. Getting muscles and strength is the easiest at that point of life, and you will reap the benefits for the rest of one's life.