How does one "prepare" to work in training?

What makes a "training professional?"  Interestingly, the May/June edition of Training Magazine has a feature article, "2015 Emerging Training Leaders" and the formal degrees of the 25 individuals featured include: journalism, psychology, social work, biology (2), mechanical engineering, education (whew! we were getting worried), entrepreneurial studies, English lit, ecommerce, communications (warmer), genetics and French. 

Things that make you go "hmmm." (Thanks Arsenio Hall)