Possibly no one, bet you didn’t expect to here that answer. This is an especially great question for those working towards becoming personal trainers or have ever had this “ray of light” like premonition break through the storm clouds and shine down on them. This quest for glory will yield immediate confusion at first. There are a ton of organizations that claim to certify trainers, yet you never have to go to any classes? You don’t even take a fitness test yourself? And really there is no one main governing body that resides over all of these so called certifying companies? These are the exact questioned addressed in the video below by the great Steven Turano. I always enjoy his videos and you should too if you are a frequent viewer here. Watch the video, and also search for discussion videos if you want to see more of Steve and his educational clips.