That message alone would discourage most people I know from going to the gym. Is the gym implying that someone with a prosthetic or in a wheelchair or who had a congential problem or is trying to get fit but is overweight has low standards?
Now I'm sure it was just someone's attempt at being pithy and trying to garner memberships and they didnt' think about it too much. But really, that was pretty shallow and callous.
In a cheerful demeanor I suggested they change it to be less insenstive, less judgemental, less superficial.
I didn't state this but I would prefer (at least in the context of a "fitness gym"):
"Your state of mind has a direct relationship with the health of your body. Elevate the fitness of both!"