Complex sentence: American kickboxing was promulgated in Germany from its inception in the 1970s by Georg F. Brückner who in 1976 was co-founder of the World Association of Kickboxing Organizations.
Split into simpler sentences: American kickboxing was promulgated in Germany from its inception in the 1970s by Georg F. Brückner. Brückner in 1976 was co-founder of the World Association of Kickboxing Organizations.