Posted this in the Ronnie thread too.
IMHO - The term Hardness/Density (the way its used in the BB industry) is a way to describe the lack of fat in the muscle itself, that give it that puffy balloon look. Its a completely different term than traditional subcutaneous fat, because that just alows you to see the separation between muscle groups.
Todays competitors get shredded, but for whatever reason (Insulin IMHO), they dont get that super dense rock hard look of the 90's, and that is IM fat, not SC fat. See? Density/Hardness is a term to describe that effect.
In there quest to come in at the highest bodyweight no matter what, or maybe due to too much bulking they wind up not dieting off the fat that accumulates inside the muscle itself. It seems to happen rather quickly (In terms of careers length) now, where as it didnt happen to the old competitors until very late in their career. It seems like the only logical explanation is insulin, as that is the only drug that is well known to have blown up from then to now.