So this article is a little misleading. There is only one type of athletic trainer (in the U.S. at least) and they require a four year bachelor or two years masters degree.
A personal trainer does not require a degree and is not in the same profession or vein as athletic training. An athletic trainer is an allied health profession and while some of us athletic trainers (ATC for short) may work in fitness on the side, the overwhelming majority do medical coverage for high school or college athletics. We also work in doctors' offices, performance arts and with fire/police/military.
This article has the gist of things, but I just wanted to make sure that those interested in the profession know it is a medical profession and while we deal with athletics, we have the general medical knowledge and orthopedic knowledge to work with any active person or profession.