What are some career that have to do with muscles or fitness?

Like a fitness trainer or physical therapist.. but what are the different options?
As someone with MD and struggling with my own problems, and then succeeding the odds, I’m motivated to help other people with similar problems or just fitness overall, but I don’t want to work at a regular gym. I’m not super fit and muscular, but it’s just something that interests me and I just found out while taking a human anatomy class and learning all the muscles. I got so much into it and researching what each muscle does, and what exercises work those muscles, etc.
That helped me out a lot with MD, and I hope to one day help others.

any suggestions? All I can think of are physical therapists (because i’ve seen some), but there must be other careers/jobs out there in that field?