They sell muscles as “symptoms of health” (the more muscles, the healthier), while pumping iron in order to become really big is actually a sign of weakness in many ways.
Most aspects of really intensive body-building are bad for the human body, and the damage done is often irreversible — think damaged joints, think weak hearts, think low self-esteem.
Especially the last category is very important for the PR of gyms: many men are prone to the idea that they need to look strong and tough, and that the latter can only be reached through developing muscle (instead of developing mental strength). “He who pumps too much iron has self-confidence issues,” as Bill Shakespeare used to say.
But Shakespeares also wrote a sonnet about “the heart of a big man,” and he was correct once again: advanced (that is to say: really big) body-builders actually have too much muscle, and it makes their hearts work (too) hard to supply the muscles with enough oxygen.
(In women, the accents are very different and more focused on body tone and general appearance, and come much closer to the actual health thing.)
The iron-y is that males who intensively pump iron are generically unattractive to women, exactly because it reveals their mental weakness as a compensation of something which is obviously lacking upstairs. Women know that actual heroes are usually rarely muscled at all, and that’s why boys had the posters of Rambo or Arnie Schwarzenegger in their childhood rooms, and girls had the posters of men with beautiful faces and charisma.
It was never about Sylvester or Arnold to begin with —
It’s still about Redford and Newman, all the way.