What credentials does a person need for an personal trainer?

they need to now how to take care of an injury in case someone get hurt so they'd probably want to take some docter or nurse classes what ever they are. ---------------------------------------------------------------- I had to take the ACE (American Council on Exercise) computerized examination for my job at a University Recreation Center. Some gyms don't require any prior experience or training (Such as 24 Hour fitness) but offer in-house training.