These aren’t fitness instructors. The trainer in this medical setting is someone that has you perform exercises to restore mobility rather than for general fitness. There’s certainly a link between the two but that’s not why you go to a hospital to work out.

Kinesiology is the study of how the body moves. While the largest target audience for that is going to be people looking for a standard gym fitness trainer, the higher degrees are wasted on that sort of thing and are better used to restore the range of motion of an elbow after a car accident.