Hi ohashwi, you would be best to use the "pre-PT" forum, as there is a plethora of information over there on how to go about reaching towards your dream.
However, I will give you a brief answer, but I do really recommend checking out past threads on the pre-PT forum! The fact of the matter is, it does not matter what you get your under graduate degree in as long as you take all the pre-requisite courses. For example, I am newly licensed (woohoo!) and my undergrad degree was in elementary education. So, degree doesn't matter- that being said if you are not 100% sure you want to go into PT school it would be wise to choose an undergrad degree that you would be able to get a job in so that you aren't up the river without a paddle. So, given the three majors you mentioned, if it were me, I would definitely choose athletic training. You can get a job as an athletic trainer, but it also gives you a good base for PT school. In my opinion, I feel that exercise science is one of the most useless majors. It's nearly impossible (in my experience) to find a job in and unless you are 100% sure you are going to continue and do something for grad school, I wouldn't suggest anyone do that major. (The reason why I have that opinion is because I had thought about getting my masters in exercise science and went to the local university to talk to the program director/department chair and she literally stared me in the face and told me not to join her department that it was useless. So, I figure if the people teaching it can't sell the product, I probably shouldn't do it.)
Also, you need to be aware that *everyone* says they only want to work with athletes or they only want to do orthopedics and the truth of the matter is PT is a hell of a lot more than that- I would suggest you do some shadowing in different settings (acute care, skilled nursing, home care, out-patient, rehab) to see if PT is a profession you would be interested in. When I went into PT school I told myself I wasn't going to limit myself into only liking what the general public knows about PT, and I was pleasantly surprised with all the other niches present.
