Complex sentence: He was a key leader in the International Taekwon-Do Federation (ITF) under General H. H. Choi, but founded the Global Taekwon-Do Federation in 1990 after leaving the ITF.
Split into simpler sentences: He was a key leader in the International Taekwon-Do Federation (ITF) under General Choi. Park founded the Global Taekwon-Do Federation in 1990, after leaving the ITF.