This allowed, starting with the 1964 season, teams to form separate offensive and defensive units as well as "special teams" which would be employed in kicking situations. By the early 1970s, however, some university administrators, coaches and others were calling for a return to the days of one-platoon football. The sport of arena football used a limited one-platoon system (from which quarterbacks, kickers and one "specialist" were exempt) from its inception until 2007.