Complex sentence: It was popularized by Chicago Bears defensive coordinator Buddy Ryan, who later became head coach of the Philadelphia Eagles and Arizona Cardinals, and used (as of 2009) by his son, Rex, coach of the New York Jets.
Split into simpler sentences: It was popularized by Chicago Bears defensive coordinator Buddy Ryan, who later became head coach of the Philadelphia Eagles and Arizona Cardinals. It is used (as of 2009) by Ryan's son, Rex, coach of the New York Jets.