Complex sentence: In 1953 the NCAA changed the game by canceling a rule that was in place since World War Two, a team could no longer make multiple substitutions and have specific players for each position, only one substitution could be made per play.
Split into simpler sentences: In 1953 the National Collegiate Athletic Association changed the game by canceling a rule that was in place since World War Two. A team could no longer make multiple substitutions and have specific players for each position, only one substitution could be made per play.