Complex sentence: The rules for the sport of fencing are regulated by national sporting associations--in the United States, the United States Fencing Association (USFA) and internationally by the International Fencing Federation, or "Fédération Internationale d'Escrime" (FIE).
Split into simpler sentences: The rules for the sport of fencing are regulated by the national sporting association. International rules are regulated by the International Fencing Federation, or "Fédération Internationale d'Escrime" (FIE).