domingo, 11 de febrero de 2007

Introduction to the Summer Olympics


Summer Olympics

The Summer Olympic Games or the Games of the Olympiad are an
international multi-sport event held every four years, organised by the International Olympic Committee. The Olympics are the most prestigious of such events in the world. Olympic victory is widely considered to be the most prestigious achievement in sports. Medals are awarded in each event, with gold medals for first place, silver for second and bronze for third, a tradition which started in 1904. The Games have expanded from a 43-event competition with fewer than 250 men competing to including over 10,000 competitors of both genders from 202 nations. Organisers for the 2008 Summer Olympics in Beijing expect approximately 10,500 athletes to take part in the 302 events on the programme for the Games. The 2004 Summer Olympics, for which organisers had also expected 10,500 competitors, drew a total of 11,099 in the 301 events offered. Competitors are entered by a National Olympic Committee (NOC) to represent their country of citizenship. National anthems and flags accompany the medal ceremonies, and tables showing the number of medals won by each country are widely used. In general only recognised nations are represented, but a few sovereign-disputed countries are allowed to take part. The country of the Republic of China (Taiwan) has been required by the International Olympic Committee to compete using the name "Chinese Taipei" in order to avoid provoking the People's Republic of China (PRC).

sábado, 10 de febrero de 2007

Archery


Archery

Archery is the practice of using a bow to shoot arrows. Archery has historically been used in hunting and combat and has become a precision sport. A person practicing archery is called an archer, and one who is fond of or an expert at archery is sometimes called a toxophilite.

History

The bow probably originated for use in hunting and was then adopted as a tool of warfare. It was one of the earliest forms of artillery. Bows eventually replaced the atlatl as the predominant means for launching projectiles. Classical civilizations, notably the Persians, Macedonians, Nubians, Greeks, Parthians, Indians, Japanese,Chinese, and Koreans, fielded large numbers of archers in their armies. Arrows proved exceptionally destructive against massed formations, and the use of archers often proved decisive.
During the
Middle Ages, archery in warfare was not as prevalent and dominant in Western Europe as popular myth dictates. Archers were quite often the lowest-paid soldiers in an army or were conscripted from the peasantry. This was due to the cheap nature of the bow and arrow, as compared to the expense needed to equip a professional man-at-arms with good armour and a sword. Professional archers required a lifetime of training and expensive bows to be effective, and were thus rare in Europe .
Archery was highly developed in
Asia and in the Islamic world. The horse archers were the main military force of most of the Equestrian Nomads. In modern times, horse archery continues to be practised in some Asian countries but is not used in international competition. Central Asian tribesmen were extremely adept at archery on horseback. Archery is the national sport of the Kingdom of Bhutan.
The advent of
firearms rendered bows obsolete in warfare. Early firearms were vastly inferior in range, rate-of-fire, and armor penetration to high-quality bows, but required significantly less training to use properly. Armies equipped with guns could thus provide superior firepower by sheer weight of numbers, and highly-trained archers became obsolete. Equipment A recurve bow is the only class of bow that is shot at the Olympic Games. Unlike the compound, its basic shape is still similar to that of a traditional longbow. Its defining feature is that the ends of the limbs curve forwards slightly, which increases the power gained from the bow and smoothens the draw. Recurves are used primarily for target competition; archery on a flat, open field at circular targets. Modern recurve and compound bows have are now often made from wood/fiberglass laminates or a combination of aluminum alloys and carbon fiber. Some archers today equip their bows with sights, stabilizers and/or shock absorbers.

Types of arrows and fletching

Arrows are made of solid wood, fiberglass, aluminum alloy tubing, or carbon fiber shafts. Wooden arrows are prone to warping, and are not easily straightened. Fiberglass arrows are brittle, but are more easily produced to uniform specifications. Aluminum shafts were a very popular high-performance choice in the later half of the 20th century due to their light weight, and subsequently higher speed and flatter trajectories. They were more easily straightened when bent, but are susceptible to being "robin hooded" if one arrow hit the back of another precisely. Carbon arrows are very light, and fly faster and flatter than aluminum arrows. They became popular in the 1990s. The material and diameter (and, in the case of aluminum, the thickness of the tube wall) of the arrow contribute to its stiffness, or spine. This must be matched to the draw weight of the bow to ensure accuracy. Most bowhunters prefer aluminum or wood arrows to fiberglass or carbon arrows. Aluminum arrows are easily adjusted to fly straight when a broadhead is attached to them, and wooden arrows are simply cheap and expendable. Carbon arrows are quite hard to adjust so that they fly straight when a broadhead is attached to them.

Feather fletches

Fletching is traditionally made from turkey feathers, but solid plastic vanes are also used. Feathers will typically be 3-6" long, while vanes are often only 1-2". They are attached at the nock (rear) end of the arrow with glue, or, traditionally, some type of string such as silk. The fletching is equally spaced around the shaft with one (the cock) placed such that it is perpendicular to the bow when nocked on the string. Three feathers (two hens plus the cock) is the most common configuration, though four or (very rarely) five are used. The fletching is attached at a slight angle, to introduce a stabilizing spin to the arrow while in flight. Oversized fletching can be used to accentuate drag and thus limit the range of the arrow signficantly; these arrows are called flu-flus.

Types of arrowheads

Target points are bullet-shaped with a sharp point, designed to penetrate target butts easily without causing excessive wear on them. Field tips have a distinct shoulder, so that missed shots out of doors don't become as stuck in obstacles such as tree stumps. A broadhead is used in hunting, not target practice. It has, usually, two to four razor sharp blades that cause massive bleeding leading to a quick, humane kill. Blunts are occasionally used for types of target shooting when the goal is to knock something over, not penetrate it.

Athletics


Athletics

Athletics, also known as track and field or track and field athletics, is a collection of sports events that involve running, throwing and jumping. The name is derived from the Greek word "athlon" meaning "contest". Some languages (e.g., German and Russian) refer to these sports as "light athletics" to distinguish them from "heavy athletics," like weight lifting, wrestling, etc.

History

Athletics was the original event at the first Olympics back in 776 BCE where the only event held was the stadium-length foot race or "stade". There were several other "Games" held throughout Europe in the classical era:

The Pythian Games (founded 527 BCE) held in Delphi every four years The Nemean Games (founded 516 BCE) held in Argolid every two years The Isthmian Games (founded 523 BCE) held on the Isthmus of Corinth every two years (one year being that which followed the Olympics) The Roman Games – Arising from Etruscan rather than purely Greek roots, the Roman Games deemphasized footraces and throwing. Instead, the Greek sports of chariot racing and wrestling, as well as the Etruscan sport of gladiatorial combat, took center stage.
Other peoples enjoyed athletic contests, such as the
Celts, Teutons and Goths who succeeded the Romans. However, these were often related to combat training, and were not very well organized. In the Middle Ages the sons of noblemen would be trained in running, leaping and wrestling, in addition to riding, jousting and arms-training. Contests between rivals and friends may have been common on both official and unofficial grounds. Many athletic sports have found favour in Europe throughout the ages. However, in Britain they fell out of favour between the 13th and 16th centuries due to government restrictions on sports aiming to reduce the practice of archery. After this ban was lifted in the 17th century sports began to flourish once more, but it was not until the 19th century that organization began to appear. This included the incorporation of regular sports and exercise into school regimes. The Royal Military College, Sandhurst has claimed to be the first to adopt this in 1812 and 1825 but without any supporting evidence. The earliest recorded meeting was organised at Shrewsbury, Shropshire in 1840 by the Royal Shrewsbury School Hunt. There are details of the meeting in a series of letters written 60 years later by CT Robinson who was a pupil there from 1838 to 1841.
Modern athletic events are usually organized around a 400 metre running track, on which most of the running events take place. Field events (vaulting, jumping, and throwing) often take place in the field in the centre of the track. Many athletic events have an ancient origin and were already conducted in competitive form by the ancient
Greeks. Athletics was included in the first modern Olympic Games in 1896 and has been part of the program ever since, providing the backbone of the Olympics. Women were not allowed to participate in track and field events in the Olympics until 1928. An international governing body, the IAAF was founded in 1912. The IAAF established separate outdoor World Championships in 1983. Other major events include the World Indoor Championships and the European Championships. The sport has a very high profile during major championships, especially the Olympics, but otherwise ranks well down the list of sports by public interest in almost all countries. The leading regular circuit of events takes place in Europe each summer, and includes the Golden League events.

Indoor track and field

There are two seasons for track and field. There is an indoor season, run during the winter and an outdoor season, run during the spring and summer. Most indoor tracks are 200 meters, however, less frequently, there are smaller and larger tracks that measure from between 120 (13.3 laps to a mile) to 300 meters. The typical indoor track consists of four to eight lanes (usually six) instead of the six to ten (usually eight) on an outdoor track. Often an indoor track will have banked turns to compensate for the tight bends. In an indoor track meet athletes contest the same events as an outdoor meet with the exception of the 100 m and 110 m/100 m hurdles (replaced by the 60 m sprint and 60 m hurdles at most levels and sometimes the 55m sprint and 55m hurdles at the high school level), and the 10,000 m run, 3,000m steeplechase, and 400m hurdles. Indoor meets also have the addition of a 3,000 m run normally at both the collegiate and elite level instead of the 10,000 m. The 5,000 m is the longest event commonly run indoors, although there are situations where longer distances have been raced. In the mid 20th century, there was a series of races 'duel races' at Madison Square Garden's (NY) indoor track, some of which featured two men racing a marathon (26.2 miles). However, this is an extremely rare occurrence, for obvious reasons. In some occasions, there may also be a 500 m race instead the open 400 m normally found outdoors, and in many collegiate championship races indoors both are contested.

Outdoor track and field

The outdoor track and field season begins in the spring and may last through the summer. Usually the tracks are an oval shape track of 400 meters. However, some old tracks are still measured in yards, so they measure 440 yards. The track consists of 6-10 lanes and, for the bigger tracks, a steeplechase lane with a water pit. This can be inside or outside the track, making for a tighter turn or a wider turn. Often schools will place a playing field in the middle of the track, usually football/soccer/lacrosse, due to their size and shape. This inner field is usually known as the infield. Recently, some of these fields have been made out of AstroTurf or FieldTurf instead of grass. Field events consist of the high jump, pole vault, long jump, triple jump and shot put. They also consist of the javelin, hammer and discus throws; however, often these are outside of the stadium because they take up a large amount of space and may damage grass fields. However, many tracks without a playing field in the middle use the infield for the throwing events.

Badminton


Badminton

Badminton is a racket sport played by either two opposing players (singles) or two opposing pairs (doubles), who take positions on opposite halves of a rectangular court that is divided by a net. Players score points by striking a shuttlecock with their rackets so that it passes over the net and lands in their opponents' half of the court. A rally ends once the shuttlecock has struck the ground, and the shuttlecock may only be struck once by each side before it passes over the net.
The shuttlecock is a feathered projectile whose unique aerodynamic properties cause it to fly differently from the balls used in most racket sports; in particular, the feathers create much higher
drag, causing the shuttlecock to decelerate more rapidly than a ball. Shuttlecock flight is strongly affected by wind, and so competitive badminton is always played indoors. Badminton is also played outdoors as a casual recreational activity, often as a garden or beach game.
Badminton is an
Olympic sport with five competitive disciplines: men's and women's singles, men's and women's doubles, and mixed doubles, in which each pair is a man and a woman. At high levels of play, the sport demands excellent fitness: players require aerobic stamina, strength, and speed. It is also a technical sport, requiring good hand-eye coordination and the development of sophisticated racket skills.

History and development

Battledore and Shuttlecock, an antecedent to the modern game of Badminton. 1854, from the John Leech Archive
Games with a shuttlecock are widely believed to have originated in ancient
Greece about 2000 years ago. From there they spread via the Indo-Greek kingdoms to India and then further east to China and Siam (now Thailand).
In
England since medieval times a children's game called Battledore and Shuttlecock was popular. Children would use paddles (Battledores) and work together to keep the Shuttlecock up in the air and prevent it from reaching the ground. It was popular enough to be a nuisance on the street of London in 1854 when the magazine Punch published a cartoon depicting it.
In the
1860s, British Army officers in Pune, India, began playing the game of Battledore and Shuttlecock, but they added a competitive element by including a net. As the city of Pune was formerly known as Poona, the game was known as Poona at that time.
About this same time, the
Duke of Beaufort was entertaining soldiers at his estate called "Badminton House", where the soldiers played Poona. The Duke of Beaufort’s non-military guests began referring to the game as "the badminton game", and thus the game became known as "Badminton".
In 1877, the first badminton club in the world, Bath Badminton Club,transcribed the rules of badminton for the first time. However, in 1893, the Badminton Association of England published the first proper set of rules, similar to that of today, and officially launched badminton in a house called "Dunbar" at 6 Waverley Grove,
Portsmouth, England on September 13 of that year. They also started the All England Open Badminton Championships, the first badminton competition in the world, in 1899.
The
Badminton World Federation (BWF) was established in 1934 with Canada, Denmark, England, France, the Netherlands, Ireland, New Zealand, Scotland, and Wales as its founding members. India joined as an affiliate in 1936. The BWF now governs international badminton and develops the sport globally.

Laws of the game

The following information is a simplified summary of the Laws, not a complete reproduction. The definitive source of the Laws is the IBF Laws publication, although the digital distribution of the Laws contains poor reproductions of the diagrams.
Playing court dimensions
The court is rectangular and divided into halves by a net. Courts are almost always marked for both singles and doubles play, although the laws permit a court to be marked for singles only. The doubles court is wider than the singles court, but the doubles service court is shorter than the singles service court.
The full width of the court is 6.1 metres, and in singles this width is reduced to 5.18 metres. The full length of the court is 13.4 metres. The service courts are marked by a centre line dividing the width of the court, by a short service line at a distance of 1.98 metres from the net, and by the outer side and back boundaries. In doubles, the service court is also marked by a long service line, which is 0.78 metres from the back boundary.
The net is 1.55 metres (5 ft 1 inch) high at the edges and 1.524 metres (5 ft) high in the centre. The net posts are placed over the doubles side lines, even when singles is played.
Surprisingly, there is no mention in the Laws of a minimum height for the ceiling above the court. Nonetheless, a badminton court will not be suitable if the ceiling is likely to be hit on a high serve.

Equipment laws

The Laws specify which equipment may be used. In particular, the Laws restrict the design and size of rackets and shuttlecocks. The Laws also provide for testing a shuttlecock for the correct speed:
3.1 To test a shuttle, use a full underhand stroke which makes contact with the shuttle over the back boundary line. The shuttle shall be hit at an upward angle and in a direction parallel to the side lines.
3.2 A shuttle of the correct speed will land not less than 530 mm and not more than 990 mm short of the other back boundary line....

Equipment

Rackets

Badminton rackets are light, with top quality rackets weighing between about 70 and 100 grams (without strings).They are composed of carbon fibre composite (graphite reinforced plastic), which may be augmented by a variety of materials. Carbon fibre has an excellent strength to weight ratio, is stiff, and gives excellent kinetic energy transfer. Before the adoption of carbon fibre composite, rackets were made of light metals such as aluminium. Earlier still, rackets were made of wood. Cheap rackets are still often made of metal, but wooden rackets are no longer manufactured for the ordinary market, due to their excessive weight and cost.
There is a wide variety of racket designs, although the racket size and shape are limited by the Laws. Different rackets have playing characteristics that appeal to different players. The traditional oval head shape is still available, but an isometric head shape is increasingly common in new rackets.

Shuttlecock

A shuttlecock (often abbreviated to shuttle) is a high-drag projectile, with an open conical shape: the cone is formed from sixteen overlapping goose feather embedded into a rounded cork base. The cork is covered with thin leather.
Shuttles with a
plastic skirt are often used by recreational players to reduce their costs: feathered shuttles break easily.

Shoes

Badminton shoes are lightweight with soles of rubber or similar high-grip, non-marking materials.

Baseball


Baseball

Baseball is a sport played between two teams usually of nine players each. It is a bat-and-ball game in which a pitcher throws (pitches) a hard, fist-sized, leather-covered ball toward a batter on the opposing team. The batter attempts to hit the baseball with a tapered cylindrical bat, made of wood (as required in professional baseball) or a variety of other materials (as allowed in many nonprofessional games). A team scores runs only when batting, by advancing its players—primarily via hits—counterclockwise past a series of four markers called bases arranged at the corners of a ninety-foot square, or "diamond." The game, played without time restriction, is structured around nine segments called innings. In each inning, both teams are given the opportunity to bat and score runs; a team's half-inning ends when three outs are recorded against that team.

History of baseball

The distinct evolution of baseball from among the various bat-and-ball games is difficult to trace with precision. While there has been general agreement that modern baseball is a North American development from the older game
rounders, the 2006 book Baseball Before We Knew It: A Search for the Roots of the Game, by David Block, argues against that notion.The earliest known mention of the sport is in a 1744 British publication, A Little Pretty Pocket-Book, by John Newbery. It contains a wood-cut illustration of boys playing "base-ball," showing a set-up roughly similar to the modern game, and a rhymed description of the sport. The earliest known American reference to the game was published in a 1791 Pittsfield, Massachusetts, statute that prohibited the playing of baseball within 80 yards of the town's new meeting house. The English novelist Jane Austen made a reference to children playing "base-ball" on a village green in her book Northanger Abbey, which was written between 1798 and 1803 (though not published until 1818).
The first full documentation of a baseball game in North America is Dr. Adam Ford's contemporary description of a game that took place in 1838 on
June 4 (Militia Muster Day) in Beachville, Ontario; this report was related in an 1886 edition of Sporting Life magazine in a letter by former St. Marys, Ontario, resident Dr. Matthew Harris. In 1845, Alexander Cartwright of New York City led the codification of an early list of rules (the so-called Knickerbocker Rules), from which today's have evolved. While there are reports of Cartwright's club, the New York Knickerbockers, playing games in 1845, the game now recognized as the first in U.S. history to be officially recorded took place on June 19, 1846, in Hoboken, New Jersey, with the "New York Nine" defeating the Knickerbockers, 23–1, in four innings.

General structure

Baseball is played between two teams of nine players each on a
baseball field, under the authority of one or more officials, called umpires. There are usually four umpires in major league games; up to six (and as few as one) may officiate depending on the league and the importance of the game. There are four bases. Numbered counter-clockwise, first, second and third bases are cushions (sometimes informally referred to as bags) shaped as 15 in (38 cm) squares which are raised a short distance above the ground; together with home plate, the fourth "base," they form a square with sides of 90 ft (27.4 m) called the diamond. Home base (plate) is a pentagonal rubber slab known as simply home. The field is divided into two main sections:
The infield, containing the four bases, is for defensive and offensive purposes bounded by the foul lines and the grass line (see figure). However, the infield technically consists of only the area within the bases, including the foul lines.
The outfield is the grassed area beyond the infield grass line (for general purposes; see above under infield), between the foul lines, and bounded by a wall or fence. Again, there is a technical difference; properly speaking, the outfield consists of all fair ground beyond the square of the infield and its bases. The area between the foul lines, including the foul lines (the foul lines are in fair territory), is fair territory, and the area outside the foul lines is foul territory.
The game is played in nine
innings (although it can be played with fewer, such as it is in little league games) in which each team gets one turn to bat and try to score runs while the other pitches and defends in the field. An inning is broken up into two halves in which the away team bats in the top (first) half, and the home team bats in the bottom (second) half. In baseball, the defense always has the ball — a fact that differentiates it from most other team sports. The teams switch every time the defending team gets three players of the batting team out. The winner is the team with the most runs after nine innings. If the home team is ahead after the top of the ninth, play does not continue into the bottom half. In the case of a tie, additional innings are played until one team comes out ahead at the end of an inning. If the home team takes the lead anytime during the bottom of the ninth or of any inning thereafter, play stops and the home team is declared the winner.
The basic contest is always between the
pitcher for the fielding team, and a batter. The pitcher throws—pitches—the ball towards home plate, where the catcher for the fielding team waits (in a crouched stance) to receive it. Behind the catcher stands the home plate umpire. The batter stands in one of the batter's boxes and tries to hit the ball with a bat. The pitcher must keep one foot in contact with the top or front of the pitcher's rubber — a 24" x 6" (~ 61 cm x 15 cm) plate located atop the pitcher's mound — during the entire pitch, so he can only take one step backward and one forward in delivering the ball. The catcher's job is to receive any pitches that the batter does not hit and to "call" the game by a series of hand movements that signal to the pitcher what pitch to throw and where. If the pitcher disagrees with the call, he will "shake off" the catcher by shaking his head; he accepts the sign by nodding. The catcher's role becomes more crucial depending on how the game is going, and how the pitcher responds to a given situation. Each pitch begins a new play, which might consist of nothing more than the pitch itself.
Each half-inning, the goal of the defending team is to get three members of the other team out. A player who is out must leave the field and wait for his next turn
at bat. There are many ways to get batters and baserunners out; some of the most common are catching a batted ball in the air, tag outs, force outs, and strikeouts. After the fielding team has put out three players from the opposing team, that half of the inning is over and the team in the field and the team at bat switch places; there is no upper limit to the number that may bat in rotation before three outs are recorded. Going through the entire order in an inning is referred to as "batting around". It is indicative of a high scoring inning. A complete inning consists of each opposing side having a turn (three outs) on offense.
The goal of the team at bat is to score more runs than the opposition; a player may do so only by batting, then
becoming a base runner, touching all the bases in order (via one or more plays), and finally touching home plate. To that end, the goal of each batter is to enable baserunners to score or to become a baserunner himself. The batter attempts to hit the ball into fair territory — between the baselines — in such a way that the defending players cannot get them or the baserunners out. In general, the pitcher attempts to prevent this by pitching the ball in such a way that the batter cannot hit it cleanly or, ideally, at all.A baserunner who successfully touches home plate after touching all previous bases in order scores a run. In an enclosed field, a fair ball hit over the fence on the fly is normally an automatic home run, which entitles the batter and all runners to touch all the bases and score. A home run hit with all bases occupied ('bases loaded') is called a grand slam.

Basketball


Basketball

Basketball is a sport in which two teams of five players each try to score points on one another by throwing a ball through a hoop (the basket) under organized rules.
Points are scored by passing the ball through the basket from above; the team with more points at the end of the game wins. The ball can be advanced on the court by bouncing it (
dribbling) or passing it between teammates. Disruptive physical contact (foul) is not permitted and there are restrictions on how the ball can be handled (violations).
Through time, basketball has developed to involve common techniques of shooting, passing and dribbling, as well as players' positions, and offensive and defensive structures. While competitive basketball is carefully regulated, numerous
variations of basketball have developed for casual play. In some countries, basketball is also a popular spectator sport.
While competitive basketball is primarily an indoor sport, played on a
basketball court, less regulated variations have become exceedingly popular as an outdoor sport among inner city groups.

History

In early December 1891, Dr. James Naismith, a Canadian physician from McGill University and minister on the faculty of a college for YMCA professionals (today, Springfield College) in Springfield, Massachusetts, USA, sought a vigorous indoor game to keep his students occupied and at proper levels of fitness during the long New England winters. After rejecting other ideas as either too rough or poorly suited to walled-in gymnasiums, he wrote the basic rules and nailed a peach basket onto an 10-foot (3.05 m) elevated track. In contrast with modern basketball nets, this peach basket retained its bottom, so balls scored into the basket had to be poked out with a long dowel each time. A soccer ball was used to shoot goals. His handwritten diaries of the time indicate that he was nervous about this invention, which incorporated rules from a Canadian children's game called "Duck on a Rock", as many had failed before it.
Naismith's new game is quite similar to the game of team handball, which had already been invented in the early 1890s.
The first official basketball game was played in the YMCA gymnasium on
January 20, 1892 with nine players, on a court just half the size of a present-day National Basketball Association (NBA) court. "Basket ball", the name suggested by one of Naismith's students, was popular from the beginning.
Women's basketball began in 1892 at
Smith College when Senda Berenson, a physical education teacher, modified Naismith's rules for women.
Basketball's early adherents were dispatched to YMCAs throughout the United States, and it quickly spread through the USA and Canada. By 1895, it was well established at several women's high schools. While the YMCA was responsible for initially developing and spreading the game, within a decade it discouraged the new sport, as rough play and rowdy crowds began to detract from the YMCA's primary mission. However, other amateur sports clubs, colleges, and professional clubs quickly filled the void. In the years before World War I, the
Amateur Athletic Union and the Intercollegiate Athletic Association (forerunner of the NCAA) vied for control over the rules for the game.
Basketball was originally played with a
soccer ball. The first balls made specifically for basketball were brown, and it was only in the late 1950s that Tony Hinkle, searching for a ball that would be more visible to players and spectators alike, introduced the orange ball that is now in common use.
Dribbling, the bouncing of the ball up and down while moving, was not part of the original game except for the "bounce pass" to teammates. Passing the ball was the primary means of ball movement. Dribbling was eventually introduced but limited by the asymmetric shape of early balls. Dribbling only became a major part of the game around the 1950s as manufacturing improved the ball shape.
Basketball,
netball, volleyball, and lacrosse are the only ball games which have been identified as being invented by North Americans. Other ball games, such as baseball and Canadian football, have Commonwealth of Nations, European, Asian or African connections.

Rules and regulations

Measurements and time limits discussed in this section often vary among tournaments and organizations; international and NBA rules are used in this section.
The object of the game is to outscore one's opponents by throwing the ball through the opponents' basket from above while preventing the opponents from doing so on their own. An attempt to score in this way is called a
shot. A successful shot is worth two points, or three points if it is taken from beyond the three-point arc which is 6.25 meters (20 ft 6 in) from the basket in international games and 23 ft 9 in (7.24 m) in NBA games.

Playing regulations

Games are played in four quarters of 10 (international) or 12 minutes (NBA). College games use two 20 minute halves while most high school games use eight minute quarters. Fifteen minutes are allowed for a half-time break, and two minutes are allowed at the other breaks. Overtime periods are five minutes long. Teams exchange baskets for the second half. The time allowed is actual playing time; the clock is stopped while the play is not active. Therefore, games generally take much longer to complete than the allotted game time, typically about two hours.
Five players from each team may be on the court at one time. Teams can have up to seven substitutes. Substitutions are unlimited but can only be done when play is stopped. Teams also have a
coach, who oversees the development and strategies of the team, and other team personnel such as assistant coaches, managers, statisticians, doctors and trainers.
For both men's and women's teams, a standard uniform consists of a pair of shorts and a
jersey with a clearly visible number, unique within the team, printed on both the front and back. Players wear high-top sneakers that provide extra ankle support. Typically, team names, players' names and sometimes sponsors are printed on the uniforms.
A limited number of time-outs, clock stoppages requested by a coach for a short meeting with the players, are allowed. They generally last no longer than one minute unless, for televised games, a commercial break is needed.
The game is controlled by the officials consisting of the referee ("crew chief" in the NBA), one or two umpires ("referees" in the NBA) and the table officials. The table officials are responsible for keeping track of each teams scoring, timekeeping, individual and team
fouls, player substitutions, team possession arrow, and the shot clock.

Equipment

The only essential equipment in basketball is the ball and the court: a flat, rectangular surface with baskets at opposite ends. Competitive levels require the use of more equipment such as clocks, scoresheets, scoreboards, alternating possession arrows, and whistle-operated stop-clock systems.
A regulation
basketball court in international games is 28 by 15 meters (approx. 92 by 49 ft) and in the NBA is 94 by 50 feet (29 by 15 m). Most courts are made of wood. A cast iron basket with net and backboard hang over each end of the court. At almost all levels of competition, the top of the rim is exactly 10 feet (3.05 m) above the court and 4 feet (1.2 m) inside the baseline. While variation is possible in the dimensions of the court and backboard, it is considered important for the basket to be of the correct height; a rim that is off by but a few inches can have an adverse effect on shooting.

Boxing


Boxing

Boxing, also called prizefighting (when referring to professional boxing), the sweet science (a common nickname among fans) or the gentleman's sport (used mainly in England), is a sport and martial art in which two participants of similar weight classification fight each other with their fists in a series of one to three-minute intervals called "rounds". In both Olympic and professional divisions, the combatants (called boxers or fighters) avoid their opponent's punches while trying to land punches of their own. Points are awarded for clean, solid blows to the legal area on the front of the opponent's body above the waistline, with hits to the head and torso being especially valuable. The fighter with the most points after the scheduled number of rounds is declared the winner. Victory may also be achieved if the opponent is knocked down and unable to get up before the referee counts to ten (a Knockout, or KO) or if the opponent is deemed too injured to continue (a Technical Knockout, or TKO). For record-keeping purposes, a TKO is usually counted as a knockout when calculating the total knockouts. A TKO can occur at any time.

Origins
Boxing most likely was invented in various cultures independently and had their origins in prehistorical periods.Archaeological evidence suggests boxing existed in Africa as early as 4000 BC with the earliest visual evidence for boxing appearing in Sumerian relief carvings from the 3rd millennium BC. The earliest evidence for it in the Mediterranean was around 1500 BC.
A mythical
Greek ruler named Theseus, said to have lived around the 9th century BC, allegedly invented a form of boxing in which two men sat face to face and beat each other with their fists until one of them was killed. In time, the boxers began to fight while standing and wearing gloves (with spikes) and wrappings on their arms below the elbows, although otherwise they competed naked.
First accepted as an
Olympic sport (the ancient Greeks called it Pygme/ Pygmachia) in 688 BC, participants trained on punching bags (called a korykos). Fighters wore leather straps (called himantes) over their hands, wrists, and sometimes breast, to protect them from injury. The straps left their fingers free.
In China in the
Zhou Dynasty 12th Century B.C., Shuai jiao, a form of wrestling that included boxing, was recorded in the Classic of Rites.This combat system included techniques such as strikes, throws, joint manipulation, and pressure point attacks.
Forms of boxing are mentioned in early
Buddhist sources. In the Lotus Sutra (Chapter 14), Gautama Buddha (563-483 BC) refers to boxing while speaking to Manjusri. Another early Buddhist sutra Hongyo-kyo describes a boxing contest between Gautama Buddha's half-brother Prince Nanda and his cousin Devadatta. The boxing martial art of Vajra Mushti was described in the Buddharata Sutra, written in the 5th century,though it was used by the Hindu Kshatriya caste centuries earlier.
In
ancient Rome, fighters were usually criminals and slaves who hoped to become champions and gain their freedom; however, free men also fought. Eventually, fist fighting became so popular that even aristocrats started fighting, but the practice was eventually banned by the caesar Augustus. In 500 A.D., the sport was banned altogether by christian Theodoric the Great.

Olympic boxing

Olympic (or Amateur) boxing is found at the Olympic Games and Commonwealth Games. Olympic boxing has point scoring system rather than physical damage or knockouts. Bouts comprise of four rounds of two minutes in Olympic and Commonwealth, and three rounds of two minutes in a national ABA (Amateur Boxing association) bout, each with a one-minute interval between rounds, but more recently the rounds are decided by the coaches and the timing is dependent on the age group.Competitors wear protective headgear and gloves with a white strip across the knuckle. A punch is considered a scoring punch only when the boxers connect with the white portion of the gloves. Each punch that lands on the head or torso is awarded a point. A referee monitors the fight to ensure that competitors use only legal blows (a belt worn over the torso represents the lower limit of punches - any boxer repeatedly landing "low blows" (below the belt) is disqualified). Referees also ensure that the boxers don't use holding tactics to prevent the opponent from swinging (if this occurs, the referee separates the opponents and orders them to continue boxing. Repeated holding can result in a boxer being penalized, or ultimately, disqualified). Referees will stop the bout if a boxer is seriously injured, if one boxer is significantly dominating the other or if the score is severely imbalanced.