Athletic training can be a very rewarding career, but it does have some negative aspects.
The main one that comes to mind is the number of hours you general work. Putting in 50 or more hours a week is pretty common for an ATC, even 60 can be common at times. Working weekends and holidays is very common as well. If you have a family, it can be very difficult at times to balance the two. Salary is fairly limited as well.