Complex sentence: Prior to becoming a professional instructor, Herbert validated his skills as a serious martial artist and authority on effective personal protection by working in numerous conflict environments for various law enforcement groups, national media, certificated debt recovery companies and from working as a close quarter bodyguard.
Split into simpler sentences: Prior to becoming a professional instructor, Herbert validated his skills as a serious martial artist and authority on effective personal protection by working in a number of conflict based environments. Working for various law enforcement groups, the national media, certificated debt recovery companies and from working as a close quarter bodyguard.