I spoke to a personal trainer about hiring and he kindly introduced me to the fitness manager, I gave my resume and set up a time for a formal interview. The interview was short and to the point, why I was interested in becoming a trainer with no background in the field. They are often looking for trainers so as long as you can commit you are pretty much hired. The more certifications you have the better, especially in pay but you don't have to be certified right away to be hired. They do a lot of in-house training, and many times will offer discounted rates on certifications so it can be a good thing to start from scratch in a corporate setting.