Hi Teal. As other posters have suggested, Certified Personal Trainers often DO conduct group fitness sessions. While there are definitely different skills sets required in working with one client one-on-one versus a small group versus a large group, many of the skills necessary for each of these are transferable. Great communication skills, being observant of what our clients are doing, having an organized and cohesive program/plan for the session so that people are not standing around waiting, maintaining a logical flow, and being able to keep a group of people motivated (where not everyone in the group will become motivated in the same way or by the same things) are all skills that are necessary when working with a group in my opinion.
Most CPT certificate allows you to do consultation, assessment, program design, and training in a one-on-one situation and up to a “small group,” which is usually up to 4 people. Even then, the restriction is that you have to have individually consult, assess, and design a program of each individual of that small group. You also can’t choreograph your instructions like that of group fitness nor choreograph the workout routine to music.
Thus, a group fitness certification is required to do group fitness (due to its structure). However, sometimes the education you receive while obtaining your CPT might allow you to challenge for a group fitness certification or at least allow you to skip some modules taught in a group fitness certification course (then again, it depends on the specialization of group fitness you want to do). For example, if your group fitness certification specialization is resistance training or portable equipment, then you might already have the necessary knowledge to challenge for the certification. If you want to specialize in aquatics or spin, then you might not be able to challenge based on what is taught to you for your CPT.
I teach classes at a local wellness center, and it is required to have a group exercise certification of the appropriate kind to teach classes. Some clubs may allow you otherwise.
However, the skill set is different, and a personal trainer certification will not teach those skills. I strongly recommend to get both and thus demonstrate that you approach this field professionally.