Call yourself one internally. Don’t be public about it until someone else acknowledges it. You can convince yourself and that’s all that is required to have the OP effects outlined in the article. Just don’t go to the gym and tell the front desk you’re there to “train” like you compete in athletic competitions (origin of athlete) when you brought in your 40lb weight in your stomach.
I highly encourage anyone to try things. If you want to become an athlete or an artist. Call yourself one inside, internally, or write it down, post it’s or journals, just don’t go around in public with this “emperor’s new clothes” mentality.