Adrian Peterson running with the ball
Before the emergence of the T-formation in the 1940s, all members of the offensive backfield were legitimate threats to run or pass the ball. Most teams used four offensive backs on every play: a quarterback, two halfbacks, and a . The quarterback began each play a quarter of the way back, the halfbacks began each play side by side and halfway back, and the fullback began each play the farthest back.
Historically, from the 1870s through the 1950s, the halfback position was both an offensive and defensive position. Now that most offensive formations have only one or two running backs, the original designations do not mean as much, as the fullback is now usually a lead blocker (technically a halfback), while the halfback or tailback (called such because he stands at the "tail" of the I) lines up behind the fullback. There has also been a shift in most offense’s dependence on halfbacks, as the quarterback is now generally considered the most essential part of a team. However, the average output of the halfback has not changed.
In the related sport of , is usually a defensive rather than offensive position since the 1980s, though used to also refer to an offensive position similar to a slotback that could line up off the tight end or behind the quarterback. Older systems require the halfback be proficient at throwing the ball downfield as well.
Many of the "scat backs" in the modern era produce more total yards and touchdowns than their ancestor "power backs" by breaking off big plays on outside runs and receptions. The spread offense and the hurry-up offense change the halfback’s role but create more opportunity for these plays. The spread, the hurry-up, and the pro-style offenses dominate American football but the "smash-mouth" style of play is far from extinct. A power-running scheme is often utilized to counter an effective Spread attack, as it allows a team to control the clock and keep the ball out of the opposing offense’s control. This strategy is utilized in NFL, college, and all other forms of American football. The need for "power backs" is very prevalent, alongside the need for "scat backs", and anything in between.
In the past few decades the role of the halfback has gone through a great shift as most offensive game plans are now fueled by creativity and finesse instead of raw force. Stamina and durability is more important than ever in the hurry-up offense. On the other hand, speed is often valued over strength, and pass-catching ability is sometimes valued over blocking proficiency. Power was once the most desired trait in a halfback, but has been over taken by the need for a diverse skill set.
In the last few decades the running back’s individual share of offensive output has declined as quarterbacks are generally treated as the cornerstone of the offense. The demands of an up-tempo offense also favor a multiple running back system.
From the dawn of American football through the 1880s most offensive schemes focused on the running game. In a running based game plan the halfback was typically the cornerstone of the offense. This system focused on a physical run attack concentrated in the inside of the field, and therefore depended on a skilled "power back." There were no forward passes, and pure speed took a backseat to tackle-breaking and ability. There was a focus on physicality over finesse, as this type of playing style earned the moniker of "smash mouth" football.
Back Willie Heston of Fielding Yost's "point-a-minute" team has been acknowledged as the first to play at what later was designated as the tailback position on offense. Prior to Heston, left halfbacks ran plays in one direction, and right halfbacks ran plays in the other direction. Because of Heston's speed and agility, Yost placed Heston in the tailback position so that he could carry the ball on plays to either side of the line.
Heston's charging ability and open-field running have also been credited with leading to the origin of the "seven man line and a diamond on defense." Minnesota's coaching staff of Henry L. Williams and Pudge Heffelfinger devised the strategy in 1903 to stop Heston. Minnesota had previously used the then-traditional nine-man line with the fullback backing up the line and a safety man down the field. Heffelfinger suggested that the halfbacks be pulled out of the line and stationed behind the tackles, thus requiring Heston to break through an initial seven-man line and a secondary line consisting of the fullback and two halfbacks. Known as the Minnesota shift, the formation became a standard practice. In 1936, Arch Ward credited Heston with leading to one of the "noteworthy transitions" in football history.
St. Louis University halfback Brad Robinson
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The sport's first triple threat, Bradbury Robinson of St. Louis University, ran, passed, received and out of the halfback position. It was as a halfback that Robinson threw the first legal forward pass to teammate Jack Schneider in a game at Carroll College on September 5, 1906. Halfback Jim Thorpe rushed for some 2,000 yards in 1912 as a member of the . In 1928, Ken Strong accounted for some 3,000 yards. Don Hutson, one of the sport's first great receivers, had his passes in college tossed by halfback Dixie Howell.