When Filming a Fitness Motivation Promo Video, it's important to grab as many like shots as possible. When I say like shots, I mean there is usually a lot going on in the gym and you need to try to be consistent with your shot selections from one exercise to the next. Grabbing a wide shot, cowboy shot, and close up of someone while they are working out in one set if possible will go a long way when you get into the editing room. It will also afford you the opportunity to go grab the same shots of other individuals on a singular set as well. This way, instead of trying to wait for someone to finish a set and go to their second or third set, you can get all you need for the shot selection for that exercise in one set. But you have to move fast, Frame up, and shoot. Going in with a game plan definitely helps!
Happy Filming!