[sn9]

Ok how do you "intervene" with muscle? Do you surgically transplant it?

It's a thing that exists. Genetic differences are not interventions. Those are also simply things that exist.

An intervention is a change in treatment or behavior that induces a change with effects we want.

Differences between individuals are not interventions.

The intervention of interest is building muscle through strength training.

[cthalupa]

There's a significant number of posts in this larger thread saying that it is basically just the benefits of exercise that is providing the positive health outcome and not just having the muscle, and I interpreted intervention in a broader manner based on that context.

My point is simply that muscle in and of itself has positive benefits, even if you didn't need to do another healthy activity to maintain or gain it.