Exercise physiologists agree: muscle memory is real. But how are these 'memories' stored? A review has a simple answer: nuclei gained during training persist even when muscle cells shrink due to disuse or start to break down. This means we can 'bank' nuclei in our youth to prevent frailty in old age -- and makes steroid use in competitive sport a perfect but irredeemable crime.
"Anabolic steroids produce a permanent increase in users' capacity for muscle development. In keeping with this, studies show that mice given testosterone acquire new myonuclei that persist long after the steroid use ends."
Source: https://www.sciencedaily.com/releases/2019/01/190125084106.htm
From what I understand this has been proposed for a while, but scientists have disagreed on whether this is the case or not. Now it's essentially confirmed.
I think this is very interesting. In the light of this, should we really allow athletes convicted of doping to compete again?