"No citizen has a right to be an amateur in the matter of physical training...what a disgrace it is for a person to grow old without ever seeing the beauty and strength of which the body is capable."Socrates
This is quote says it all.
You don't have a right to be an amateur in your training.
You were given an amazing body that can do amazing things.
Decide to express the beauty and strength that comes with what you've been given. It's not a task; it's a responsibility.
Your body responds to what you tell it to do. It becomes stronger and more resilient with training. It becomes weak and undependable with movement dormancy.
There is no maintaining. You are either getting better or you are getting worse. This goes for your health and performance as much as anything else.
As the great Arnold Schwarzenneger said, "I don't walk away from things that are unfinished."
Your body is never a finished product, it is something you must master continually to get the most out of it.
Choose to see all you're body is capable of. Don't be an amateur in your physical training.