The option offense is a generic term that is used to describe a wide variety of offensive systems in American football. Option offenses are characterized as such due to the predominance of option running plays employed in these schemes. Option offenses have traditionally relied heavily upon running plays, though modern option offenses now incorporate a large number of passing plays. Because they are run-based, option offenses are very effective in managing the game clock, giving the opposing team less time to score, and keeping the option team's defense from tiring. However, this also means that when the option team is losing near the end of the game, and needs to score quickly, it is at a disadvantage. These schemes rely on timing, deception, and split-second decision-making under pressure, which, in turn, requires flawless execution and discipline.