It depends on the exact field.
For instance, I trained with and under several former physical therapists. Most program directors would look favorably on such applicants.
In the same vein, podiatrists are physicians. They're basically specialized surgeons. Having completed a podiatry residency is going to demonstrate professional and academic rigor, which is going to be a plus.
Athletic trainer is mostly going to be a neutral thing. It might at most suggest that you're likely to be interested in sports medicine, which is just one aspect among many withing the PM&R field.
But you're going to get a lot of raised eyebrows if you're a chiropractor or naturopath applying to med school. Your interviewers are going to view your discipline as based in charlatanism, and they won't be wrong to do so. If you're considering some other career before med school, I'd advise something grounded in empirical evidence.
