Starting with the final design here, but iterations and options are below. They loved the use of darker colors and were sold on the back from the beginning. The front however took a little bit of tweaking until we arrived at a design they loved. I was given images of their gym and was told to help portray what the gym was like through their business card. Everything had a strong high energy feel in the gym with bright colors and accents all over, so it felt natural to use high contrast on their business cards.
In the end they used several different card options for different employee levels.