出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/12/26 18:27:09」(JST)
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Ambidexterity is the state of being equally adept in the use of both left and right hand, and also using them at the same time.[1][2] Only about one percent of people are naturally ambidextrous.[3] The degree of versatility with each hand is generally the qualitative factor in determining a person's ambidexterity.
In modern times, it is more common to find some people considered ambidextrous who were originally left handed and who learned to be ambidextrous, either deliberately or during childhood institutions such as schools, or jobs where right-handed habits are often emphasized or required. Since many everyday devices (such as can openers and scissors) are asymmetrical and designed for right-handed people, many left-handers learn to use them right-handedly due to the rarity or lack of left-handed models. Thus, left-handed people are much more likely to develop motor skills in their non-dominant hand than right-handed people (who are not subjected to left-favoring devices). Right-handers may become ambidextrous due to an injury of their right hand or arm. Ambidexterity is often encouraged in activities requiring a great deal of skill in both hands, such as knitting, typing on a computer, juggling, swimming, percussion, keyboard music, baseball, paintball, lacrosse, surgery, boxing, martial arts, Capoeira, Parkour, Association Football, and basketball.
The word "ambidextrous" is derived from the Latin roots ambi-, meaning "both", and dexter, meaning "right" or "favorable". Thus, "ambidextrous" is literally "both right" or "both favorable". The term ambidexter in English was originally used in a legal sense of jurors who accepted bribes from both parties for their verdict.[4] The Latin word is derived from classical Greek roots from the word 'αμφι-δέξιος'
According to Vaughan Heussenstamm, ambidexterity can be learned in adulthood by allowing the non-dominant hand to learn demanding tasks. If the less-skilled hand is used for a long enough period of time, it will eventually dominate that skill.[5]
In athletics, Jonathan Edwards, a now-retired British triple jumper who still holds the world record in that event, was known to be able to kick with either foot while he played rugby. He displayed unprecedented ambidexterity while jumping off either foot during his competitive jumps.
Ambidexterity is highly prized in the sport of baseball. "Switch hitting" is the most common phenomenon, and is highly prized because a batter usually has a higher statistical chance of successfully hitting the baseball when it is thrown by an opposite-handed pitcher. Therefore, an ambidextrous hitter can bat from whichever side is most advantageous to him in that situation. Pete Rose, who had more hits than anyone else in the history of Major League Baseball, was a switch hitter.[6]
Switch pitchers also exist. Tony Mullane won 284 games in the 19th century.[7][8] Elton Chamberlain and Larry Corcoran were also notable ambidextrous pitchers. In the 20th century, Greg A. Harris was the only major league pitcher to pitch with both his left and his right arm. A natural right-hander, by 1986 he could throw well enough with his left hand that he felt capable of pitching with either hand in a game. Harris wasn't allowed to throw left-handed in a regular-season game until September 28, 1995, the penultimate game of his career. Against the Cincinnati Reds in the ninth inning, Harris (then a member of the Montreal Expos) retired Reggie Sanders pitching right-handed, then switched to his left hand for the next two hitters, Hal Morris and Ed Taubensee, who both batted left-handed. Harris walked Morris but got Taubensee to ground out. He then went back to his right hand to retire Bret Boone to end the inning. One Division I NCAA pitcher, Pat Venditte formerly of the Creighton Bluejays, and the New York Yankees Class AA affiliate Trenton Thunder, and now with the Oakland Athletics regularly pitches with both arms. Venditte became the 21st century's first switch pitcher in MLB with his debut on June 5, 2015 against the Boston Red Sox, pitching two innings, allowing only one hit and recording five outs right-handed and one out left-handed.
Billy Wagner was a natural right-handed pitcher in his youth, but after breaking his throwing arm twice, he taught himself how to use his left arm by throwing nothing but fastballs against a barn wall. He became a dominant left-handed relief pitcher, most known for his 100+ mph (161+ km/h) fastball. In his 1999 season, Wagner captured the National League Relief Man of the Year Award as a Houston Astro.
Toronto Blue Jays pitcher Brett Cecil is naturally right-handed, but starting from a very early age, threw with his left. As such, he writes and performs most tasks with the right side of his body, but throws with his left.
In basketball a player may choose to make a pass or shot with the weaker hand. NBA stars Kobe Bryant, Kyrie Irving, Carlos Boozer, David Lee, John Wall, Derrick Rose, Chandler Parsons, Andrew Bogut and Michael Beasley are ambidextrous players. Bogut is stronger in the post with his left-handed hook shot than he is with his natural right hand. Brothers Marc and Pau Gasol can make hook shots with either hand while the right hand is dominant for each. Bob Cousy, a Boston Celtics legend was forced to play with left hand in high school when he injured his right hand, thus making him effectively ambidextrous. Tristan Thompson is a natural left-hander, but he consciously attempts to convert to shooting right-handed for the 2013-2014 season.[9] LA Clippers center DeAndre Jordan who is left-handed, shoots with his left hand but has been known to dunk with his right hand. Indiana Pacers center Roy Hibbert shoots his hook shots equally well with either hand. Oklahoma City Thunder left-handed point guard Derek Fisher used to dunk with his right hand in his early years. Candace Parker, forward for the WNBA Sparks team, also has equal dominance with either hand. Los Angeles Lakers superstar Kobe Bryant shoots with either hand, although his right hand is dominant: due to an injury to the right hand, he was forced to shoot with his left. Paul George, Tracy McGrady and Vince Carter are all noted to be right-handed, but rotates clockwise for dunks, but Carter is able to also spin anti-clockwise, as he did during high school.[10] McGrady also spins anti-clockwise for his baseline dunks. Larry Bird, LeBron James, Danny Ainge and Gary Payton shoot right-handed, but does almost everything left-handed off the courts.
In skateboarding, being able to skate successfully with not only one's dominant foot forward but also the less dominant one is called "switch skating" and is a prized ability. Notable switch skateboarders include Rodney Mullen, Eric Koston, Guy Mariano, Paul Rodriguez Jr., Mike Mo Capaldi, and Bob Burnquist. Similarly, surfers who ride equally well in either stance are said to be surfing "switch-foot". Also, snowboarding at the advanced level requires the ability to ride equally well in either.
In combat sports fighters may choose to face their opponent with either the left shoulder forward in a right-handed stance ("orthodox") or the right shoulder forward in a left-handed stance ("south-paw"), thus a degree of cross dominance is useful. In boxing, Manny Pacquiao has a southpaw stance in the ring even though he is really ambidextrous outside the ring.
In cricket, it is also beneficial to be able to use both arms. Ambidextrous fielders can make one handed catches or throws with either hand. Sachin Tendulkar uses his left hand for writing, but bats and bowls with right hand. There are many players who are naturally right handed but bat left and vice versa. Sourav Ganguly uses his right hand for writing and bowls with the right hand, too, but bats with his left hand. Players due to injuries may also switch arms for fielding. Phillip Hughes batted, bowled and fielded left handed before a shoulder injury. Australian batsman George Bailey also due to sustaining an injury, taught himself to throw with his weaker left arm. He is now often seen throughout matches switching between arms as he throws the ball. See also reverse sweep and switch hitting.
In cue sports, players can reach farther across the table if they are able to play with either hand, since the cue must either be placed on the left or the right side of the body. English snooker player Ronnie O'Sullivan[11] is a rarity amongst the current ranks of top snooker professionals, in that he is able to play to world standard with either hand. While he lacks power in his left arm, his ability to alternate hands allows him to take shots that would otherwise require awkward cueing or the use of a rest. When he first displayed this ability in the 1996 World Championship against the Canadian player Alain Robidoux, Robidoux accused him of disrespect. O'Sullivan responded that he played better with his left hand than Robidoux could with his right.[12] O'Sullivan was summoned to a disciplinary hearing in response to Robidoux's formal complaint, where he had to prove that he could play to a high level with his left hand. Many people think O'Sullivan had to play a match against former professional Rex Williams, but this never took place. On Eurosport's coverage of the 2014 International Championships, commentator David Hendon confirmed that O'Sullivan never played the match against Rex Williams.
In figure skating, most skaters who are right-handed spin and jump to the left, and vice versa for left-handed individuals. Olympic Champion figure skater John Curry notably performed his jumps in one direction (anti-clockwise) while spinning predominantly in the other. Very few skaters have such an ability to perform jumps and spins in both directions, and it is now considered a "difficult variation" in spins under the ISU Judging System to rotate in the non-dominant direction. Michelle Kwan used an opposite-rotating camel spin in some of her programs as a signature move. No point bonus exists for opposite direction jumps or bi-directional combination jumps, despite their being much harder to perfect.
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In association football, being able to kick with either foot provides more options for both passing and scoring, as well as the ability to play on either side of the pitch. Therefore, players with the ability to use their weaker foot with proficiency are valuable in any team. Former football players Andreas Brehme, Zinedine Zidane,[13] Zico,[14] Sócrates,[15] Johan Cruyff,[16] Alfredo Di Stefano,[17] Paolo Maldini, Ronaldo and Pavel Nedvěd are ambidextrous from birth. Toni Kroos, Adriano Correia, Julian Draxler, Wesley Sneijder, David Villa, Hernanes, Ross Barkley, Marek Hamšík, Adel Taarabt, Jack Rodwell, Adam Lallana, Santi Cazorla,[18] Neymar, Francesco Totti, and Cristiano Ronaldo are all examples of ambidextrous footballers.
In rugby league and rugby union being ambidextrous is an advantage when it comes to passing the ball between teammates as well as being able to use both feet by the halves is an advantage in gaining field position by kicking the ball ahead. Jonny Wilkinson is a prime example of a union player who is equally good at kicking off both feet, for example he normally place kicks using his left, but dropped the goal that won the Rugby World Cup in 2003 with his right.
In American football, it is especially advantageous to be able to use both arms. Ambidextrous receivers can make one-handed catches with either hand; linemen can hold their shoulders square and produce an equal amount of power with both arms; and punters can handle a bad snap and roll out and punt with either leg, limiting the chance of a block.
Some players find cross-dominance advantageous in golf, especially if a left-handed player utilizes right-handed clubs. Having more precise coordination with the left hand is believed to allow better-controlled, and stronger drives. Mac O'Grady was a touring pro who played right-handed, yet could play "scratch" (no handicap) golf left-handed. He lobbied the USGA for years to be certified as an amateur "lefty" and a pro "righty" to no avail.[19] Although not ambidextrous, Phil Mickelson and Mike Weir are both right-handers who golf left-handed; Ben Hogan was the opposite, being a natural left-hander who played golf right-handed. This is known as cross-dominance or mixed-handedness. Katelyn Johnson is a famous ambidextrous women's golf player.
Ice hockey players may shoot from the left or right side of the body. For the most part, right-handed players shoot left and, likewise, most left-handed players shoot right as the player will often wield the stick one-handed. The dominant hand is typically placed on the top of the stick to allow for better stickhandling and control of the puck. Players who learn the game in the USA will generally play with their stronger hand in the middle of the stick, thus putting more power into slapshots. Gordie Howe was one of few players capable of doing both, although this was at a time when the blade of the stick was not curved.[20]
Another ice hockey player, goaltender Bill Durnan, was nicknamed "Dr. Strangeglove" for his ability to catch the puck with either hand. This feat won him the Vezina Trophy, then for the National Hockey League's goalie with the lowest goals-against average, six times out of only seven seasons. He had developed this ability playing for church-league teams in Toronto and Montreal to make up for his poor lateral movement.
Chelsie Homer is a famous female ice hockey ambidextrous player.[citation needed]
Field hockey players are forced to play right-handed. The rules of the game denote that the ball can only be struck with the flat side of the stick. Only one player Laeeq Ahmed on Pakistan National Hockey team, played with unorthodox left hand below and right hand up side of stick grip with full command. He played from 1991 to 1992 for the national team. Perhaps to avoid confusing referees, left-handed sticks are rare.
The Traditional Martial Arts tend to feature a larger number of practitioners who have intentionally developed ambidexterity to a high degree, compared to athletes in Combat Sports. This is because unlike sports, which have structured rules and common player preferences, traditional martial arts are intended for situations such as self-defense, in which a wider array of physical challenges may occur.
Some arts and schools practice all or most techniques and movements with both sides, while others emphasize that some techniques should only be trained on the right or the left (though both sides tend to eventually receive nearly equal attention). This may be for a number of reasons. Some of these arts rely on the tendency of right-handed people to move differently with the left side than with the right, and attempt to take advantage of this. Similarly, certain weapons are more often carried on one side. For instance, most weapons in ancient China were wielded primarily with the right hand and on the right side; this habit has carried on to the practice of those weapons in modern times. As an example, in Xing Yi Quan, most schools that teach spear-fighting only practice on the right side, despite the fact the much of the rest of the art is ambidextrous in practice.
In professional sports car racing, drivers who participate in various events in both the United States and Europe will sometimes encounter machines with the steering wheel mounted on different sides of the car. While steering ability is largely unaffected, the hand used for shifting changes. This is further complicated by the fact that the shift pattern relative to the driver changes, e.g. a gear change that requires moving the lever toward the driver in a left-hand-drive vehicle becomes a movement away from the driver in a right-hand-drive vehicle. A driver skilled in shifting with the opposite hand is at an advantage.
Also notice that the more widely adopted left foot braking technique in modern race cars requires a sensitive left foot to operate and a left-hand-driver with a more dominated left foot may brake better than those who brakes with right foot or whose left foot isn't dominated, this drastically shorten the time from maximum acceleration to maximum deceleration and left footer possesses a much greater advantages in racing.
In tennis, a player may be able to reach balls on the backhand side more easily if they're able to use the weaker hand. An example of a player who is ambidextrous is Luke Jensen.[21] Rafael Nadal uses his right hand for writing, but plays tennis with left. There are many players who are naturally right handed but play lefty and vice versa. Evgenia Kulikovskaya is also an ambidextrous player, Kulikovskaya played with two forehands and no backhand, switching her racket hand depending on where the ball was coming. Jan-Michael Gambill is the opposite case of Kulikovskaya, since he played with a two handed forehand and backhand, although he served with his right hand. Other famous examples of a two handed forehand are Fabrice Santoro and Monica Seles. Seles' playing style was unusual in that she hit with two hands on both sides and, at the same time, always kept her (dominant) left hand at the base of her racket. This meant that she hit her forehand cross-handed.
Although it is quite uncommon, in badminton, ambidextrous players are able to switch the racquet between their hands, often to get to the awkward backhand corner quickly. As badminton can be a very fast sport, at professional levels of play, players might not have time to switch the racquet, as this disrupts their reaction time.
Although most artists have a favored hand, some artists use both of their hands for arts such as drawing and sculpturing. It is believed that Leonardo da Vinci utilized both of his hands after an injury to his right hand during his early childhood.[22]
A contemporary artist, Gur Keren, can draw with both his hands and even feet.[23][24]
Tribalogy is the artistic study of creating abstract lines and shapes on a surface using both hands at the same time. An artist who studies Tribalogy is referred to as a Tribalogist.[25]
In drum and bugle corps (and drum and bell corps), snare drummers, quads (tenors), and bass drummers need to be somewhat ambidextrous. Since they have to abide by what the composer/arranger has written, they have to learn to play their piece starting with either left or right. Former Beatles member Paul McCartney is left-handed (guitar and bass guitar), and had his guitar altered (restrung) for performing (as can be seen in many photos and videos throughout his musical career). The drummer of The Beatles, Ringo Starr, is left-handed as well, but he plays a right-handed drum kit. American instrumental guitarist Michael Angelo Batio is known for being able to play both right-handed and left-handed guitar proficiently. Irish guitar player Niall Horan, from boyband One Direction, applies on this case. He writes with the left hand but plays the guitar with the right one. The ambidexterity of Jimi Hendrix, perhaps the most widely-acclaimed rock guitarist, has been explored in a psychology paper.
With respect to tools, ambidextrous may be used to mean that the tool may be used equally well with either hand; an "ambidextrous knife" refers to the opening mechanism and locking mechanism on a folding knife. It can also mean that the tool can be interchanged between left and right in some other way, such as an "ambidextrous headset," which can be worn on either the left or right ear.[26][27] As an opposite example, some scissors are made specifically for use in one hand, and will not cut properly if used in the other hand. Left-handed as well as ambidextrous scissors are nowadays available.
In knitting, the use of two needles, the knitter must learn to use both needles seamlessly. Several factors also lead to ambidexterity, the chief one being if a person either favors their left hand over their right or if they learned to crochet before learning to knit. In that case, they either use the Continental method (yarn in left hand, work moving from left needle to right needle; sometimes called 'picking') or the English method (yarn held in right hand, work still moving from left to right needle; sometimes called 'throwing' and more common in the United States.)
Many modern small arms employ ambidextrous design to accommodate both the right- and left-handed operator. This is advantageous for marketing the firearm to military or law enforcement units because the firearms are distributed in a large scale. This eliminates the need for training left-handed operators to adapt to a right-handed firearm. Many right-handed persons shoot rifles left-handed because they have a left dominant eye.
The realities of modern urban combat also play a significant role in this development, with ambidextrously-designed firearms providing an advantage when required to shoot around cover from the weak shoulder.
The Scottish anatomist John Lizars was known to be ambidextrous, as well as Marco Abbondanza, the Italian eye surgeon.
Ambidexterity is also useful after surgery on a dominant hand or arm, as it allows the patient to use their non-dominant hand with equal facility as the limb which is recovering from surgery.
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| Side | Left | Both | Right |
| General | Ambidexterity | ||
| In cognitive abilities | Geschwind–Galaburda hypothesis | ||
| In brain |
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| In eyes | Ocular dominance | ||
| In hands | Left-handedness | Cross-dominance | Right-handedness |
| Handedness in boxing | Southpaw stance | Orthodox stance | |
| Handedness in people |
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| Handedness related to |
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| Handedness measurement | Edinburgh Handedness Inventory | ||
| Handedness genetics | LRRTM1 | ||
| In heart | Levocardia | Dextrocardia | |
| In major viscera | Situs solitus | Situs ambiguus | Situs inversus |
| In feet | Footedness | ||
| リンク元 | 「両手利き」「functional laterality」「ambidextrous」 |
機能的左右差