For me it would depend upon the certification and the manner in which the individual earned their credential.
My first credential was through the London YMCA. It took me six months to complete the course. Both the theoretical and practical components were part of the course. The practical exam required that I bring in 15 persons and teach a group fitness class in front of an independent body of examiners from the Royal Society of Arts. In addition, there was a theoretical exam.
For me that was one of the many pivotal experiences in my career. When I finally began working as a group fitness instructor not only did I have a certification but I had the confidence before I accepted my first job.
If a personal trainer or group fitness instructor who took their course through the 16-week university level course offered by an ACE education partners, I would feel confident hiring him or her. For me that fact that both pivotal components are included in the course is increases the likelihood of their knowledge of ability being put in to practice.