Okay, let’s tackle this. So Stephen Rivera has a certification from the National Academy of Sports Medicine (NASM), which is a reputable organization. The average hourly rate for a personal trainer in the US can range from $25 to $100, depending on experience and location. Since Stephen is based in Stamford, Connecticut, a relatively affluent area, his rate might be on the higher side. Considering his NASM certification, which indicates a certain level of expertise, I'd estimate his rate to be around $40-$60 per hour. However, given the location and assuming he has some experience, I'll round down to $45 per hour.