How do you become an athletic trainer for a college or professional team?

Question

what must i major in?

Answer 1

some colleges and universities offer majors in Sports Science, see if anything like that is offered in your area.  

Answer 2

Major in sports science or Kinesiology.  The other path is to be a athelete at least at the college level.  Most of these upper level trainers usually are degreed with a Bachelors or Masters.  Work on network skills while your working on your degree as well.  You will need them to get a job in the end.  Also, you'll need to go to a sports school (e.g. - a college with a major sports program like a Stanford, UT, Florida, USC, etc etc etc) for the name recognition.