Many people think that fitness models in commercials for popular products like the Total Gym or what have you got to being that buff and ripped from using the product they are advertising. This is a common psychological misconception, and one that advertisers rely on when utilizing fitness models for their commercials. It is the simple process of association.

Our brain is filled with mental shortcuts in order to process life and the stimuli that come into our perception more easily. It would be way too complicated to sort everything out, so our brain associates things to one another and bundles them up. This simple process is behind almost every advertising campaign out there. Why do they put a start athlete on Cheerios? To associate the "breakfast of champions" with someone visually. When you eat Cheerios, you eat champion food. Same with fitness models and fitness machines. Your brain thinks, "Gosh if those good looking people are using it, it must be a good product!"

So remember that our brain is hardwired to value the packaging more than the product, and advertisers are very keenly aware of this fact!