The one-platoon system, also known as iron man football, is a
Each system was used at different times in American
Prior to 1941, virtually all football players saw action on "both sides of the ball," playing in both offensive and defensive roles. From 1941 to 1952, the
For the 1953 season, the NCAA emplaced a set of new rules requiring the use of a one-platoon system, primarily due to financial reasons.
 One source indicated that only one player was allowed to be substituted between plays;
 however, according to the NCAA, the actual rule allowed a player to enter the game only once in each quarter.
For the 1964 season, after 11 seasons of the mandate requiring one-platoon (though with gradual liberalization of substitution rules from 1953 forward),
 the NCAA repealed the rules enforcing its use and allowed an unlimited number of player substitutions.
 This allowed, starting with the 1964 season,
 teams to form separate offensive and defensive units as well as "