Not sure but, I remember reading somewhere that toning up isn't a whole new physical transfermation but the result of your nerves being more alert. "Muscle tone is residule tension is a relaxed state" - Unknown (forget who said this. I think this author is saying that the stronger you are the harder you will be. Please comment.
-------------- \"Gold medals aren\'t really made of gold. They\'re made of sweat, determination, and a hard-to-find alloy called guts.\" - Dan Gable
That is the biomechanical term for tone. Not the term you are thinking of. You are thinking of it as an aesthetic term, meaning something similar to muscle definition.