With such a topic so broad we truly try to cover the basics from all angles in this group. Nothing too big or too small. Nutrition is as significant if not more as exercise is to reaching your goals so learn all you can.
Some gyms will hire anyone with a bicep muscle as a trainer, others will require some type of certification - there are many to choose from.
Working with athletes is more specialized - ask gatormade, I believe that is what he does.
-------------- "To be able to go to the gym and train hard is a joy and a privelege, even though the hard work necessitates driving yourself through considerable discomfort. Savor this privelege and blessing, and revel in it."
Stuart McRobert, Beyond Brawn