Why do muscles need to lift weight to grow?

Question

As opposed to the human body controlling muscle growth from within?

In: 76

Answer 1

It’s the way of telling your body which muscles need to grow (and by how much).

Lifting makes tiny tears in your muscles. When they heal, your muscles gain some mass.

Its your body’s way of adapting. Instead of having a ton of muscle mass by default (which would be heavy, resource intensive, and wasteful), your body figures out which muscles to prioritize.