3/05/2012

Volleyball

Volleyball

Volleyball is a team sport in which two teams of six players are separated by a net. Each team tries to score points by grounding a ball on the other team's court under organized rules. It has been a part of the official program of the Summer Olympic Games since 1964.
A scene of Volleyball play in Ervadi village.

The complete rules are extensive. But simply, play proceeds as follows: A player on one of the teams begins a 'rally' by serving the ball (tossing or releasing it and then hitting it with a hand or arm), from behind the back boundary line of the court, over the net, and into the receiving team's court. The receiving team must not let the ball be grounded within their court. They may touch the ball as many as three times. Typically, the first two touches are used to set up for an attack, an attempt to direct the ball back over the net in such a way that the serving team is unable to prevent it from being grounded in their court.

The rally continues, with each team allowed as many as three consecutive touches, until either (1): a team makes a kill, grounding the ball on the opponent's court and winning the rally; or (2): a team commits a fault and loses the rally. The team that wins the rally is awarded a point, and serves the ball to start the next rally. A few of the most common faults include:

    causing the ball to touch the ground outside the opponents' court or without first passing over the net;
    catching and throwing the ball;
    double hit: two consecutive contacts with the ball made by the same player;
    four consecutive contacts with the ball made by the same team.
    net foul: touching the net during play.

The ball is usually played with the hands or arms, but players can legally strike or push (short contact) the ball with any part of the body.

A number of consistent techniques have evolved in volleyball, including spiking and blocking (because these plays are made above the top of the net, the vertical jump is an athletic skill emphasized in the sport) as well as passing, setting, and specialized player positions and offensive and defensive structures.

History
Vallyball action.

Vallyball action.

Vallyball action.

Vallyball action.

Vallyball action.

Vallyball action.
Vallyball action.

Origin of volleyball

On February 9, 1895, in Holyoke, Massachusetts (USA), William G. Morgan, a YMCA physical education director, created a new game called Mintonette as a pastime to be played preferably indoors and by any number of players. The game took some of its characteristics from tennis and handball. Another indoor sport, basketball, was catching on in the area, having been invented just ten miles (sixteen kilometers) away in the city of Springfield, Massachusetts, only four years before. Mintonette was designed to be an indoor sport less rough than basketball for older members of the YMCA, while still requiring a bit of athletic effort.

The first rules, written down by William G Morgan, called for a net 6 ft 6 in (1.98 m) high, a 25×50 ft (7.6×15.2 m) court, and any number of players. A match was composed of nine innings with three serves for each team in each inning, and no limit to the number of ball contacts for each team before sending the ball to the opponents’ court. In case of a serving error, a second try was allowed. Hitting the ball into the net was considered a foul (with loss of the point or a side-out)—except in the case of the first-try serve.

After an observer, Alfred Halstead, noticed the volleying nature of the game at its first exhibition match in 1896, played at the International YMCA Training School (now called Springfield College), the game quickly became known as volleyball (it was originally spelled as two words: "volley ball"). Volleyball rules were slightly modified by the International YMCA Training School and the game spread around the country to various YMCAs.
Japanese American women playing volleyball, Manzanar internment camp, California, ca. 1943.
Refinements and later developments

The first official ball used in volleyball is disputed; some sources say that Spalding created the first official ball in 1896, while others claim it was created in 1900.The rules evolved over time: in the Philippines by 1916, the skill and power of the set and spike had been introduced, and four years later a "three hits" rule and a rule against hitting from the back row were established. In 1917, the game was changed from 21 to 15 points. In 1919, about 16,000 volleyballs were distributed by the American Expeditionary Forces to their troops and allies, which sparked the growth of volleyball in new countries.

The first country outside the United States to adopt volleyball was Canada in 1900.[4] An international federation, the Fédération Internationale de Volleyball (FIVB), was founded in 1947, and the first World Championships were held in 1949 for men and 1952 for women. The sport is now popular in Brazil, in Europe (where especially Italy, the Netherlands, and countries from Eastern Europe have been major forces since the late 1980s), in Russia, and in other countries including China and the rest of Asia, as well as in the United States.

Beach volleyball, a variation of the game played on sand and with only two players per team, became a FIVB-endorsed variation in 1987 and was added to the Olympic program at the 1996 Summer Olympics Volleyball is also a sport at the Paralympics managed by the World Organization Volleyball for Disabled.
Volleyball in the Olympics
Main article: Volleyball at the Summer Olympics

The history of Olympic volleyball traces back to the 1924 Summer Olympics in Paris, where volleyball was played as part of an American sports demonstration event. After the foundation of FIVB and some continental confederations, it began to be considered for official inclusion. In 1957, a special tournament was held at the 53rd IOC session in Sofia, Bulgaria to support such request. The competition was a success, and the sport was officially included in the program for the 1964 Summer Olympics.

The Olympic volleyball tournament was originally a simple competition: all teams played against each other team and then were ranked by wins, set average, and point average. One disadvantage of this round-robin system is that medal winners could be determined before the end of the games, making the audience lose interest in the outcome of the remaining matches. To cope with this situation, the competition was split into two phases with the addition of a "final round" elimination tournament consisting of quarterfinals, semifinals, and finals matches in 1972. The number of teams involved in the Olympic tournament has grown steadily since 1964. Since 1996, both men's and women's events count twelve participant nations. Each of the five continental volleyball confederations has at least one affiliated national federation involved in the Olympic Games.

The U.S.S.R. won men's gold in both 1964 and 1968. After taking bronze in 1964 and silver in 1968, Japan finally won the gold for men's volleyball in 1972. Women's gold went to Japan in 1964 and again in 1976. That year, the introduction of a new offensive skill, the backrow attack, allowed Poland to win the men's competition over the Soviets in a very tight five-set match. Since the strongest teams in men's volleyball at the time belonged to the Eastern Bloc, the American-led boycott of the 1980 Summer Olympics did not have as great an effect on these events as it had on the women's. The U.S.S.R. collected their third Olympic Gold Medal in men's volleyball with a 3–1 victory over Bulgaria (the Soviet women won that year as well, their third gold as well). With the U.S.S.R. boycotting the 1984 Olympic Games in Los Angeles, the U.S. was able to sweep Brazil in the finals to win the men's gold medal. Italy won its first medal (bronze in the men's competition) in 1984, foreshadowing a rise in prominence for their volleyball teams.

At the 1988 Games, Karch Kiraly and Steve Timmons led the U.S. men's team to a second straight gold medal. In 1992, underrated Brazil upset favourites C.I.S., Netherlands, and Italy in the men's competition for the country's first volleyball Olympic gold medal. Runner-up Netherlands, men's silver medalist in 1992, came back under team leaders Ron Zwerver and Olof van der Meulen in the 1996 Games for a five-set win over Italy. A men's bronze medalist in 1996, Serbia and Montenegro (playing in 1996 and 2000 as the Federal Republic of Yugoslavia) beat Russia in the gold medal match in 2000, winning their first gold medal ever. In 2004, Brazil won its second men's volleyball gold medal beating Italy in the finals. In the 2008 Games, the USA beat Brazil in the men's volleyball final.

Rules of the game

Volleyball court

The court

The game is played on a volleyball court 18 meters (59 feet) long and 9 meters (29.5 feet) wide, divided into two 9 m × 9 m halves by a one-meter (40-inch) wide net placed so that the top of the net is 2.43 meters (7 feet 11 5/8 inches) above the center of the court for men's competition, and 2.24 meters (7 feet 4 1/8 inches) for women's competition (these heights are varied for veterans and junior competitions).

There is a line 3 meters from and parallel to the net in each team court which is considered the "attack line". This "3 meter" (or 10 foot) line divides the court into "back row" and "front row" areas (also back court and front court). These are in turn divided into 3 areas each: these are numbered as follows, starting from area "1", which is the position of the serving player:
VolleyballRotation.svg

After a team gains the serve (also known as siding out), its members must rotate in a clockwise direction, with the player previously in area "2" moving to area "1" and so on, with the player from area "1" moving to area "6".

The team courts are surrounded by an area called the free zone which is a minimum of 3 meters wide and which the players may enter and play within after the service of the ball.[9] All lines denoting the boundaries of the team court and the attack zone are drawn or painted within the dimensions of the area and are therefore a part of the court or zone. If a ball comes in contact with the line, the ball is considered to be "in". An antenna is placed on each side of the net perpendicular to the sideline and is a vertical extension of the side boundary of the court. A ball passing over the net must pass completely between the antennae (or their theoretical extensions to the ceiling) without contacting them.

The ball

FIVB regulations state that the ball must be spherical, made of leather or synthetic leather, have a circumference of 65–67 cm, a weight of 260–280 g and an inside pressure of 0.30–0.325 kg/cm2.[10] Other governing bodies have similar regulations.
Game play
Buddhist monks play volleyball in the Himalayan state of Sikkim, India.

Each team consists of six players. To get play started, a team is chosen to serve by coin toss. A player from the serving team throws the ball into the air and attempts to hit the ball so it passes over the net on a course such that it will land in the opposing team's court (the serve). The opposing team must use a combination of no more than three contacts with the volleyball to return the ball to the opponent's side of the net. These contacts usually consist first of the bump or pass so that the ball's trajectory is aimed towards the player designated as the setter; second of the set (usually an over-hand pass using wrists to push finger-tips at the ball) by the setter so that the ball's trajectory is aimed towards a spot where one of the players designated as an attacker can hit it, and third by the attacker who spikes (jumping, raising one arm above the head and hitting the ball so it will move quickly down to the ground on the opponent's court) to return the ball over the net. The team with possession of the ball that is trying to attack the ball as described is said to be on offense.

The team on defense attempts to prevent the attacker from directing the ball into their court: players at the net jump and reach above the top (and if possible, across the plane) of the net in order to block the attacked ball. If the ball is hit around, above, or through the block, the defensive players arranged in the rest of the court attempt to control the ball with a dig (usually a fore-arm pass of a hard-driven ball). After a successful dig, the team transitions to offense.

The game continues in this manner, rallying back and forth, until the ball touches the court within the boundaries or until an error is made. The most frequent errors that are made are either to fail to return the ball over the net within the allowed three touches, or to cause the ball to land outside the court. A ball is "in" if any part of it touches a sideline or end-line, and a strong spike may compress the ball enough when it lands that a ball which at first appears to be going out may actually be in. Players may travel well outside the court to play a ball that has gone over a sideline or end-line in the air.

Other common errors include a player touching the ball twice in succession, a player "catching" the ball, a player touching the net while attempting to play the ball, or a player penetrating under the net into the opponent's court. There are a large number of other errors specified in the rules, although most of them are infrequent occurrences. These errors include back-row or libero players spiking the ball or blocking (back-row players may spike the ball if they jump from behind the attack line), players not being in the correct position when the ball is served, attacking the serve in the front court and above the height of the net, using another player as a source of support to reach the ball, stepping over the back boundary line when serving, taking more than 8 seconds to serve,[11] or playing the ball when it is above the opponent's court.
Scoring

When the ball contacts the floor within the court boundaries or an error is made, the team that did not make the error is awarded a point, whether they served the ball or not. If the ball hits the line, the ball is counted as in. The team that won the point serves for the next point. If the team that won the point served in the previous point, the same player serves again. If the team that won the point did not serve the previous point, the players of the team rotate their position on the court in a clockwise manner. The game continues, with the first team to score 25 points (and be two points ahead) awarded the set. Matches are best-of-five sets and the fifth set (if necessary) is usually played to 15 points. (Scoring differs between leagues, tournaments, and levels; high schools sometimes play best-of-three to 25; in the NCAA games are played best-of-five to 25 as of the 2008 season.)

Before 1999, points could be scored only when a team had the serve (side-out scoring) and all sets went up to only 15 points. The FIVB changed the rules in 1999 (with the changes being compulsory in 2000) to use the current scoring system (formerly known as rally point system), primarily to make the length of the match more predictable and to make the game more spectator- and television-friendly.
Libero

In 1998 the libero player was introduced internationally. The libero is a player specialized in defensive skills: the libero must wear a contrasting jersey color from his or her teammates and cannot block or attack the ball when it is entirely above net height. When the ball is not in play, the libero can replace any back-row player, without prior notice to the officials. This replacement does not count against the substitution limit each team is allowed per set, although the libero may be replaced only by the player whom he or she replaced.

The libero may function as a setter only under certain restrictions. If she/he makes an overhand set, she/he must be standing behind (and not stepping on) the 3-meter line; otherwise, the ball cannot be attacked above the net in front of the 3-meter line. An underhand pass is allowed from any part of the court.

The libero is, generally, the most skilled defensive player on the team. There is also a libero tracking sheet, where the referees or officiating team must keep track of who the libero subs in and out for. There may only be one libero per set (game), although there may be a different libero in the beginning of any new set (game).

Furthermore, a libero is not allowed to serve, according to international rules, with the exception of the NCAA women's volleyball games, where a 2004 rule change allows the libero to serve, but only in a specific rotation. That is, the libero can only serve for one person, not for all of the people for whom he or she goes in. That rule change was also applied to high school and junior high play soon after.
Recent rule changes

Other rule changes enacted in 2000 include allowing serves in which the ball touches the net, as long as it goes over the net into the opponents' court. Also, the service area was expanded to allow players to serve from anywhere behind the end line but still within the theoretical extension of the sidelines. Other changes were made to lighten up calls on faults for carries and double-touches, such as allowing multiple contacts by a single player ("double-hits") on a team's first contact provided that they are a part of a single play on the ball.

In 2008, the NCAA changed the minimum number of points needed to win any of the first four sets from 30 to 25 for women's volleyball (men's volleyball remained at 30.) If a fifth (deciding) set is reached, the minimum required score remains at 15. In addition, the word "game" is now referred to as "set".

Changes in rules have been studied and announced by FIVB in recent years, and they have released the updated rules in 2009.
Skills

Competitive teams master six basic skills: serve, pass, set, attack, block and dig. Each of these skills comprises a number of specific techniques that have been introduced over the years and are now considered standard practice in high-level volleyball.
Serve
Setting up for an overhand serve.
A player making a jump serve.

A player stands behind the inline and serves the ball, in an attempt to drive it into the opponent's court. His or her main objective is to make it land inside the court; it is also desirable to set the ball's direction, speed and acceleration so that it becomes difficult for the receiver to handle it properly. A serve is called an "ace" when the ball lands directly onto the court or travels outside the court after being touched by an opponent.

In contemporary volleyball, many types of serves are employed:

    Underhand: a serve in which the player strikes the ball below the waist instead of tossing it up and striking it with an overhand throwing motion. Underhand serves are considered very easy to receive and are rarely employed in high-level competitions.
    Sky ball serve: a specific type of underhand serve occasionally used in beach volleyball, where the ball is hit so high it comes down almost in a straight line. This serve was invented and employed almost exclusively by the Brazilian team in the early 1980s and is now considered outdated. In Brazil, this serve is called Jornada nas Estrelas (Star Trek).
    Topspin: an overhand serve where the player tosses the ball high and hits it with a wrist span, giving it topspin which causes it to drop faster than it would otherwise and helps maintain a straight flight path. Topspin serves are generally hit hard and aimed at a specific returner or part of the court. Standing topspin serves are rarely used above the high school level of play.
    Float: an overhand serve where the ball is hit with no spin so that its path becomes unpredictable, akin to a knuckleball in baseball.
    Jump serve: an overhand serve where the ball is first tossed high in the air, then the player makes a timed approach and jumps to make contact with the ball, hitting it with much pace and topspin. This is the most popular serve amongst college and professional teams.
    Jump float: an overhand serve where the ball is tossed high enough that the player may jump before hitting it similarly to a standing float serve. The ball is tossed lower than a topspin jump serve, but contact is still made while in the air. This serve is becoming more popular amongst college and professional players because it has a certain unpredictability in its flight pattern.

Pass
A woman making a forearm pass or bump.

Also called reception, the pass is the attempt by a team to properly handle the opponent's serve, or any form of attack. Proper handling includes not only preventing the ball from touching the court, but also making it reach the position where the setter is standing quickly and precisely.

The skill of passing involves fundamentally two specific techniques: underarm pass, or bump, where the ball touches the inside part of the joined forearms or platform, at waist line; and overhand pass, where it is handled with the fingertips, like a set, above the head. Either are acceptable in professional and beach volleyball, however there are much tighter regulations on the overhand pass in beach volleyball.

Set

Jump set

The set is usually the second contact that a team makes with the ball. The main goal of setting is to put the ball in the air in such a way that it can be driven by an attack into the opponent's court. The setter coordinates the offensive movements of a team, and is the player who ultimately decides which player will actually attack the ball.

As with passing, one may distinguish between an overhand and a bump set. Since the former allows for more control over the speed and direction of the ball, the bump is used only when the ball is so low it cannot be properly handled with fingertips, or in beach volleyball where rules regulating overhand setting are more stringent. In the case of a set, one also speaks of a front or back set, meaning whether the ball is passed in the direction the setter is facing or behind the setter. There is also a jump set that is used when the ball is too close to the net. In this case the setter usually jumps off his or her right foot straight up to avoid going into the net. The setter usually stands about ⅔ of the way from the left to the right of the net and faces the left (the larger portion of net that he or she can see).

Sometimes a setter refrains from raising the ball for a teammate to perform an attack and tries to play it directly onto the opponent's court. This movement is called a "dump". This can only be performed when the setter is in the front row, otherwise it constitutes an illegal back court attack. The most common dumps are to 'throw' the ball behind the setter or in front of the setter to zones 2 and 4. More experienced setters toss the ball into the deep corners or spike the ball on the second hit.

Attack

The attack, also known as the spike, is usually the third contact a team makes with the ball. The object of attacking is to handle the ball so that it lands on the opponent's court and cannot be defended. A player makes a series of steps (the "approach"), jumps, and swings at the ball.

Ideally the contact with the ball is made at the apex of the hitter's jump. At the moment of contact, the hitter's arm is fully extended above his or her head and slightly forward, making the highest possible contact while maintaining the ability to deliver a powerful hit. The hitter uses arm swing, wrist snap, and a rapid forward contraction of the entire body to drive the ball. A 'bounce' is a slang term for a very hard/loud spike that follows an almost straight trajectory steeply downward into the opponent's court and bounces very high into the air. A "kill" is the slang term for an attack that is not returned by the other team thus resulting in a point.

Contemporary volleyball comprises a number of attacking techniques:

    Backcourt (or backrow)/pipe attack: an attack performed by a back row player. The player must jump from behind the 3-meter line before making contact with the ball, but may land in front of the 3-meter line.
    Line and Cross-court Shot: refers to whether the ball flies in a straight trajectory parallel to the side lines, or crosses through the court in an angle. A cross-court shot with a very pronounced angle, resulting in the ball landing near the 3-meter line, is called a cut shot.
    Dip/Dink/Tip/Cheat/Dump: the player does not try to make a hit, but touches the ball lightly, so that it lands on an area of the opponent's court that is not being covered by the defense.
    Tool/Wipe/Block-abuse: the player does not try to make a hard spike, but hits the ball so that it touches the opponent's block and then bounces off-court.
    Off-speed hit: the player does not hit the ball hard, reducing its speed and thus confusing the opponent's defense.
    Quick hit/"One": an attack (usually by the middle blocker) where the approach and jump begin before the setter contacts the ball. The set (called a "quick set") is placed only slightly above the net and the ball is struck by the hitter almost immediately after leaving the setter's hands. Quick attacks are often effective because they isolate the middle blocker to be the only blocker on the hit.
    Slide: a variation of the quick hit that uses a low back set. The middle hitter steps around the setter and hits from behind him or her.
    Double quick hit/"Stack"/"Tandem": a variation of quick hit where two hitters, one in front and one behind the setter or both in front of the setter, jump to perform a quick hit at the same time. It can be used to deceive opposite blockers and free a fourth hitter attacking from backcourt, maybe without block at all.

Block

3 players performing a block

Blocking refers to the actions taken by players standing at the net to stop or alter an opponent's attack.

A block that is aimed at completely stopping an attack, thus making the ball remain in the opponent's court, is called offensive. A well-executed offensive block is performed by jumping and reaching to penetrate with one's arms and hands over the net and into the opponent's area. It requires anticipating the direction the ball will go once the attack takes place. It may also require calculating the best foot work to executing the "perfect" block.

The jump should be timed so as to intercept the ball's trajectory prior to it crossing over the net. Palms are held deflected downward about 45–60 degrees toward the interior of the opponents court. A "roof" is a spectacular offensive block that redirects the power and speed of the attack straight down to the attacker's floor, as if the attacker hit the ball into the underside of a peaked house roof.

By contrast, it is called a defensive, or "soft" block if the goal is to control and deflect the hard-driven ball up so that it slows down and becomes more easy to be defended. A well-executed soft-block is performed by jumping and placing one's hands above the net with no penetration into the opponent's court and with the palms up and fingers pointing backward.

Blocking is also classified according to the number of players involved. Thus, one may speak of single (or solo), double, or triple block.

Successful blocking does not always result in a "roof" and many times does not even touch the ball. While it’s obvious that a block was a success when the attacker is roofed, a block that consistently forces the attacker away from his or her 'power' or preferred attack into a more easily controlled shot by the defense is also a highly successful block.

At the same time, the block position influences the positions where other defenders place themselves while opponent hitters are spiking.

Dig

Woman going for a dig.

Digging is the ability to prevent the ball from touching one's court after a spike or attack, particularly a ball that is nearly touching the ground. In many aspects, this skill is similar to passing, or bumping: overhand dig and bump are also used to distinguish between defensive actions taken with fingertips or with joined arms. It varies from passing however in that is it a much more reflex based skill, especially at the higher levels. It is especially important while digging for players to stay on their toes; several players choose to employ a split step to make sure they're ready to move in any direction.

Some specific techniques are more common in digging than in passing. A player may sometimes perform a "dive", i.e., throw his or her body in the air with a forward movement in an attempt to save the ball, and land on his or her chest. When the player also slides his or her hand under a ball that is almost touching the court, this is called a "pancake". The pancake is frequently used in indoor volleyball, but rarely if ever in beach volleyball because the uneven and infirm nature of the sand court limits the chances that the ball will make a good, clean contact with the hand. When used correctly, it is one of the more spectacular defensive volleyball plays.

Sometimes a player may also be forced to drop his or her body quickly to the floor in order to save the ball. In this situation, the player makes use of a specific rolling technique to minimize the chances of injuries.
Team Play

Volleyball is essentially a game of transition from one of the above skills to the next, with choreographed team movement between plays on the ball. These team movements are determined by the teams chosen serve receive system, offensive system, coverage system, and defensive system.

The serve receive system is the formation used by the receiving team to attempt to pass the ball to the designated setter. Systems can consist of 5 receivers, 4 receivers, 3 receivers, and in some cases 2 receivers. The most popular formation at higher levels is a 3 receiver formation consisting of two left sides and a libero receiving every rotation. This allows middles and right sides to become more specialized at hitting and blocking.

Offensive systems are the formations used by the offense to attempt to ground the ball in to the opposing court (or otherwise score points). Formations often include designated player positions with skill specialization (described in more detail under Player Specialization). Popular formations include the 4-2, 6-2, and 5-1 systems (described in more detail under Formations). There are also several different attacking schemes teams can use to keep the opposing defense off balance.

Coverage systems are the formations used by the offense to protect their court in the case of a blocked attack. Executed by the 5 offensive players not directly attacking the ball, players move to assigned positions around the attacker in order to dig up any ball that deflects off the block back in to their own court. Popular formations include the 2-3 system and the 1-2-2 system. In lieu of a system, some teams just use a random coverage with the players nearest the hitter.

Defensive systems are the formations used by the defense to protect against the ball being grounded in to their court by the opposing team. The system will outline which players are responsible for which areas of the court depending on where the opposing team is attacking from. Popular systems include the 6-Up, 6-Back-Deep, and 6-Back-Slide defense. There are also several different blocking schemes teams can employ to disrupt the opposing teams offense.

Some teams, when they are ready to serve, will line up their other five players in a screen to obscure the view of the receiving team. This action is only illegal if the server makes use of the screen, so the call is made at the referees discretion as to the impact the screen made on the receivers ability to pass the ball. The most common style of screening involves a W formation designed to take up as much horizontal space as possible.

Coaching

Basic

Coaching for volleyball can be classified under two main categories: match coaching and developmental coaching. The objective of match coaching is to win a match by managing a team's strategy. Developmental coaching emphasizes player development through the reinforcement of basic skills during exercises known as "drills." Drills promote repetition and refinement of volleyball movements, particularly in footwork patterns, body positioning relative to others, and ball contact. A coach will construct drills that simulate match situations thereby encouraging speed of movement, anticipation, timing, communication, and team-work. At the various stages of a player's career, a coach will tailor drills to meet the strategic requirements of the team. The American Volleyball Coaches Association is the largest organization in the world dedicated exclusively to volleyball coaching.
Strategy
An image from an international match between Italy and Russia in 2005. A Russian player on the left has just served, with three men of his team next to the net moving to their assigned block positions from the starting ones. Two others, in the back-row positions, are preparing for defense. Italy, on the right, has three men in a line, each preparing to pass if the ball reaches him. The setter is waiting for their pass while the middle hitter with no. 10 will jump for a quick hit if the pass is good enough. Alessandro Fei (no. 14) has no passing duties and is preparing for a back-row hit on the right side of the field. Note the two liberos with different color dress. Middle hitters/blockers are commonly substituted by liberos in their back-row positions.
Player specialization

There are 5 positions filled on every volleyball team at the elite level. Setter, Outside Hitter/Left Side Hitter, Middle Hitter, Opposite Hitter/Right Side Hitter and Libero/Defensive Specialist. Each of these positions plays a specific, key role in winning a volleyball match.

    Setters have the task for orchestrating the offense of the team. They aim for second touch and their main responsibility is to place the ball in the air where the attackers can place the ball into the opponents' court for a point. They have to be able to operate with the hitters, manage the tempo of their side of the court and choose the right attackers to set. Setters need to have swift and skillful appraisal and tactical accuracy, and must be quick at moving around the court.
    Liberos are defensive players who are responsible for receiving the attack or serve. They are usually the players on the court with the quickest reaction time and best passing skills. Libero means 'free' as they have the ability to substitute for any other player on the court during each play. They do not necessarily need to be tall, as they never play at the net, which allows shorter players with strong passing and defensive skills to excel in the position and play an important role in the team's success. A player designated as a libero for a match may not play other roles during that match. Liberos wear a different color jersey than their teammates.
    Middle blockers or Middle hitters are players that can perform very fast attacks that usually take place near the setter. They are specialized in blocking, since they must attempt to stop equally fast plays from their opponents and then quickly set up a double block at the sides of the court. In non-beginners play, every team will have two middle hitters.
    Outside hitters or Left side hitters attack from near the left antenna. The outside hitter is usually the most consistent hitter on the team and gets the most sets. Inaccurate first passes usually result in a set to the outside hitter rather than middle or opposite. Since most sets to the outside are high, the outside hitter may take a longer approach, always starting from outside the court sideline. In non-beginners play, there are again two outside hitters on every team in every match.
    Opposite hitters or Right side hitters carry the defensive workload for a volleyball team in the front row. Their primary responsibilities are to put up a well formed block against the opponents Outside Hitters and serve as a backup setter. Sets to the opposite usually go to the right side of the antennae.

At some levels where substitutions are unlimited, teams will make use of a Defensive Specialist in place of or in addition to a Libero. This position does not have unique rules like the libero position, instead, these players are used to substitute out a poor back row defender using regular substitution rules. A defensive specialist is often used if you have a particularly poor back court defender in right side or left side, but your team is already using a libero to take out your middles. Most often, the situation involves a team using a right side player with a big block who must be subbed out in the back row because they aren't able to effectively play back court defense. Similarly, teams might use a Serving Specialist to sub out a poor server situationally.
Formations

The three standard volleyball formations are known as "4–2", "6–2" and "5–1", which refers to the number of hitters and setters respectively. 4–2 is a basic formation used only in beginners' play, while 5–1 is by far the most common formation in high-level play.
4–2

The 4–2 formation has four hitters and two setters. The setters usually set from the middle front or right front position. The team will therefore have two front-row attackers at all times. In the international 4–2, the setters set from the right front position. The international 4–2 translates more easily into other forms of offense.

The setters line up opposite each other in the rotation. The typical lineup has two outside hitters. By aligning like positions opposite themselves in the rotation, there will always be one of each position in the front and back rows. After service, the players in the front row move into their assigned positions, so that the setter is always in middle front. Alternatively, the setter moves into the right front and has both a middle and an outside attacker; the disadvantage here lies in the lack of an offside hitter, allowing one of the other team's blockers to "cheat in" on a middle block.

The clear disadvantage to this offensive formation is that there are only two attackers, leaving a team with fewer offensive weapons.

Another aspect is to see the setter as an attacking force, albeit a weakened force, because when the setter is in the front court they are able to 'tip' or 'dump', so when the ball is close to the net on the second touch, the setter may opt to hit the ball over with one hand. This means that the blocker who would otherwise not have to block the setter is engaged and may allow one of the hitters to have an easier attack.
6–2

In the 6–2 formation, a player always comes forward from the back row to set. The three front row players are all in attacking positions. Thus, all six players act as hitters at one time or another, while two can act as setters. So the 6–2 formation is actually a 4–2 system, but the back-row setter penetrates to set.

The 6–2 lineup thus requires two setters, who line up opposite to each other in the rotation. In addition to the setters, a typical lineup will have two middle hitters and two outside hitters. By aligning like positions opposite themselves in the rotation, there will always be one of each position in the front and back rows. After service, the players in the front row move into their assigned positions.

The advantage of the 6–2 is that there are always three front-row hitters available, maximizing the offensive possibilities. However, not only does the 6–2 require a team to possess two people capable of performing the highly specialized role of setter, it also requires both of those players to be effective offensive hitters when not in the setter position. At the international level, only the Cuban National Women's Team employs this kind of formation. It is also used in Women's NCAA play, partially due to the variant rules used which allow 12[16] substitutions per set (as opposed to the 6 allowed in the standard rules).
5–1

The 5–1 formation has only one player who assumes setting responsibilities regardless of his or her position in the rotation. The team will therefore have three front-row attackers when the setter is in the back row, and only two when the setter is in the front row, for a total of five possible attackers.

The player opposite the setter in a 5–1 rotation is called the opposite hitter. In general, opposite hitters do not pass; they stand behind their teammates when the opponent is serving. The opposite hitter may be used as a third attack option (back-row attack) when the setter is in the front row: this is the normal option used to increase the attack capabilities of modern volleyball teams. Normally the opposite hitter is the most technical skilled hitter of the team. Back-row attacks generally come from the back-right position,known as zone 1, but are increasingly performed from back-center in high-level play.

The big advantage of this system is that the setter always has 3 hitters to vary sets with. If the setter does this well, the opponent's middle blocker may not have enough time to block with the outside blocker, increasing the chance for the attacking team to make a point.

There is another advantage, the same as that of a 4–2 formation: when the setter is a front-row player, he or she is allowed to jump and "dump" the ball onto the opponent's side. This too can confuse the opponent's blocking players: the setter can jump and dump or can set to one of the hitters. A good setter knows this and thus won't only jump to dump or to set for a quick hit, but when setting outside as well to confuse the opponent.

The 5–1 offense is actually a mix of 6–2 and 4–2: when the setter is in the front row, the offense looks like a 4–2; when the setter is in the back row, the offense looks like a 6–2.

Variations and related games

There are many variations on the basic rules of volleyball. By far the most popular of these is beach volleyball, which is played on sand with two people per team, and rivals the main sport in popularity.

Some games related to volleyball include:

    Footvolley: A sport from Brazil in which the hands and arms are not used but most else is like beach volleyball.
    Hooverball: Popularized by President Herbert Hoover, it is played with a volleyball net and a medicine ball; it is scored like tennis, but the ball is caught and then thrown back. The weight of the medicine ball can make the sport to be quite physically demanding; annual championship tournaments are held annually in West Branch, Iowa.
    Newcomb ball (sometimes spelled "Nuke 'Em"): In this game, the ball is caught and thrown instead of hit; it rivaled volleyball in popularity until the 1920s.
    Prisoner Ball: Also played with volleyball court and a volleyball, the object of the game is to get your opponents "out".
    Throwball became popular with women players at the YMCA College of Physical Education in Chennai (India) in the 1940s.
    Buka ball: This is a rather similar game played only with the feet.
    Beachball volleyball: A game of indoor volleyball played with a beach ball instead of a volleyball.

Vallybal.  

2/28/2012

Snooker

Snooker


Snooker  is a cue sport that is played on a green baize-covered table with pockets in each of the four corners and in the middle of each of the long side cushions. The (baize) cloth on a snooker table has a directional nap running from the balk end of the table towards the end with the (black ball) spot. This affects how a ball rolls depending on which direction it is hit or shot. A regular (full-size) table is 12 × 6 ft (3.7 × 1.8 m). It is played using a cue and 22 snooker balls: one white cue ball, 15 red balls worth one point each, and six balls of different colours: yellow (2 points), green (3), brown (4), blue (5), pink (6) and black (7). A player (or team) wins a frame (individual game) of snooker by scoring more points than the opponent(s), using the cue ball to pot the red and coloured balls. A player wins a match when a certain number of frames have been won.

Snooker, generally regarded as having been invented in India by British Army officers, is popular in many of the English-speaking and Commonwealth countries,] with top professional players attaining multi-million pound career earnings from the game. The sport is now increasingly popular in China.




History



It is commonly accepted that snooker originated in the later half of the 19th century. Billiards had been a popular activity amongst British Army officers stationed in India, and variations on the more traditional billiard games were devised. One variation, devised in the officers' mess in Jabalpur during 1874 or 1875,was to add coloured balls in addition to the reds and black which were used for pyramid pool and life pool.The rules were formally finalized in 1884 by Sir Neville Chamberlain at Ootacamund. The word snooker also has military origins, being a slang term for first-year cadets or inexperienced personnel. One version of events states that Colonel Sir Neville Chamberlain of the Devonshire regiment was playing this new game when his opponent failed to pot a ball and Chamberlain called him a snooker. It thus became attached to the billiards game now bearing its name as inexperienced players were labelled as snookers.[8]

The game of snooker grew in the latter half of the 19th century and the early 20th century, and by 1927 the first World Snooker Championship had been organised by Joe Davis who, as a professional English billiards and snooker player, moved the game from a pastime activity into a more professional sphere. Joe Davis won every world championship until 1946 when he retired. The game went into a decline through the 1950s and 1960s with little interest generated outside of those who played. In 1959, Davis introduced a variation of the game, known as snooker plus, to try to improve the game's popularity by adding two extra colours. However, it never caught on.

A major advance occurred in 1969, when David Attenborough commissioned the snooker tournament Pot Black to demonstrate the potential of colour television, with the green table and multi-coloured balls being ideal for showing off the advantages of colour broadcasting. The TV series became a ratings success and was for a time the second most popular show on BBC Two. Interest in the game increased and the 1978 World Championship was the first to be fully televised. The game quickly became a mainstream sport in the UK, Ireland and much of the Commonwealth and has enjoyed much success in the last 30 years, with most of the ranking tournaments being televised. In 1985 a total of 18.5 million viewers watched the concluding frame of the world championship final between Dennis Taylor and Steve Davis. In recent years the loss of tobacco sponsorship has led to a decrease in the number of professional tournaments, although some new sponsors have been sourced; and the popularity of the game in the Far East and China, with emerging talents such as Liang Wenbo and more established players such as Ding Junhui and Marco Fu, bodes well for the future of the sport in that part of the world.

The game


The object of the game is to score more points than the opponent by potting object balls in a predefined order. At the start of a frame, the balls are positioned as shown and the players take turns to hit a shot in a single strike from the tip of the cue, their aim being to pot one of the red balls and score a point. Whenever a red ball is potted, the shooter is allowed to pot one of the colours. If successful, they score the value of the colour potted, and it is returned to its correct position on the table. This process continues until they fail to pot the desired ball, at which point their opponent comes back to the table to play the next shot. The game continues in this manner until all the reds are potted and only the 6 colours are left on the table; at that point the aim is to pot the colours in the order yellow 2, green 3, brown 4, blue 5, pink 6, black 7, with the balls not being returned to play. When the final ball is potted, the player with the most points wins.

Points may also be scored in a game when a player's opponent fouls. A foul can occur for numerous reasons, such as hitting a colour first when the player was attempting to hit a red, potting the cue ball, or failing to escape from "a snooker" (a situation where the previous player finished their turn leaving the cue ball in a position where the object ball cannot be hit directly). Points gained from a foul vary from a minimum of 4 to a maximum of 7 if the black ball is involved.

One game, from the balls in their starting position until the last ball is potted, is called a frame. A match generally consists of a predefined number of frames and the player who wins the most frames wins the match overall. Most professional matches require a player to win five frames, and are called 'Best of Nine' as that is the maximum possible number of frames. Tournament finals are usually best of 17 or best of 19, while the World Championship uses longer matches – ranging from best of 19 in the qualifiers and the first round proper, up to 35 frames in length (first to 18), and is played over two days.

Professional and competitive amateur matches are officiated by a referee who is the sole judge of fair play. The referee also respots the colours on to the table and calls out how many points the player has scored during a break. Professional players usually play the game in a sporting manner, declaring fouls the referee has missed, acknowledging good shots from their opponent, or holding up a hand to apologise for fortunate shots.

Other terminology used in snooker includes a player's break, which refers to the total number of consecutive points a player has amassed (excluding fouls) when at one visit to the table. A player attaining a break of 15, for example, could have reached it by potting a red then a black, then a red then a pink, before failing to pot the next red. The traditional maximum break in snooker is to pot all reds with blacks then all colours, which would yield 147 points; this is often known as a "147" or a "maximum".

Accessories used for snooker include chalk for the tip of the cue, rests of various sorts (needed often, due to the length of a full-size table), a triangle to rack the reds, and a scoreboard. One drawback of snooker on a full-size table is the size of the room (22 by 16 feet (6.7 × 4.9 m)), which is the minimum required for comfortable cueing room on all sides.[20] This limits the number of locations in which the game can easily be played. While pool tables are common to many pubs, snooker tends to be played either in private surroundings or in public snooker halls. The game can also be played on smaller tables using fewer red balls. The variants in table size are: 10' × 5', 9' × 4.5', 8' × 4', 6' × 3' (the smallest for realistic play) and 4' × 2'. Smaller tables can come in a variety of styles, such as fold away or dining-table convertible.

Governance and tournaments




The World Professional Billiards and Snooker Association (WPBSA, also known as World Snooker), founded in 1968 as the Professional Billiard Players' Association, is the governing body for the professional game. Its subsidiary, World Snooker, based in Bristol, England, organises the professional tour. Over the years the board of the WPBSA has changed many times, which some argue is an indication of in-fighting within the sport. The amateur game is governed by the International Billiards and Snooker Federation (IBSF).

Professional snooker players can play on the World Snooker main tour ranking circuit. Ranking points, earned by players through their performances over the previous two seasons, determine the current world ranking. A player's ranking determines what level of qualification they require for ranking tournaments. The elite of professional snooker is generally regarded as the "Top 16" ranking players, who are not required to pre-qualify for any of the tournaments. The tour contains 96 players – the top 64 from the previous two seasons, the 8 highest ranked professional players on the Players Tour Championship Order of Merit who are not in the top 64, 12 players from the Q School, and various regional, junior and amateur champions.

The most important event in professional snooker is the World Championship, held annually since 1927 (except during the World War II and between 1958 and 1963). The tournament has been held at the Crucible Theatre in Sheffield, England since 1977, and was sponsored by Embassy from 1976 to 2005.Since 2005, tobacco companies have not been allowed to sponsor sporting events in the United Kingdom, and the World Championship had to find a new sponsor. It was announced in January 2006 that the 2006–2010 world championships would be sponsored by online casino 888.com. The Championship is currently sponsored by BetFred.com after 888.com pulled out of their five year sponsorship deal after three years. On 15 April 2009 the World Snooker Championship website announced that Betfred.com would be the new sponsor of the World Championship for the next four years.

The status of winning the World Championship is great, and it is the most highly valued prize in professional snooker, both in terms of financial reward (£250,000 for the winner) as well as ranking points and prestige. The World Championship is televised extensively in the UK by the BBC and gains significant coverage in Europe on Eurosport and in the Far East.

The group of tournaments that come next in importance are the other ranking tournaments. Players in these tournaments score world ranking points. A high ranking ensures qualification for next year's tournaments, invitations to invitational tournaments and an advantageous draw in tournaments. The most prestigious of these after the World Championship is the UK Championship. Third in line are the invitational tournaments, to which most of the highest ranked players are invited. The most important tournament in this category is The Masters,[38] which to most players is the second or third most sought-after prize.[39]

In an attempt to answer criticisms that televised matches can be slow or get bogged down in lengthy safety exchanges and that long matches causes problems for advertisers,[40] an alternative series of timed tournaments has been organised by Matchroom Sport Chairman Barry Hearn. The shot-timed Premier League Snooker was established, with seven players invited to compete at regular United Kingdom venues, televised on Sky Sports. Players have twenty-five seconds to take each shot, with five time-outs per player per match. While some success has been achieved with this format it generally does not receive the same amount of press attention or status as the regular ranking tournaments.

There are also other tournaments that have less importance, earn no world ranking points and are not televised. These can change on a year-to-year basis depending on calendars and sponsors.

Equipment

This section requires expansion with:
a sentence or two about the balls & table; link to the main articles on these topics..




Chalk and cue.

Chalk

The tip of the cue is 'chalked' to ensure good contact between the cue and the cue-ball.

Cue

A stick, made of wood or fibreglass, the tip of which is used to strike the cue-ball.

Extension

A shorter baton that fits over, or screws into, the back end of the cue, effectively lengthening it. Is used for shots where the cue-ball is a long distance from the player.

Rest

A stick with an X-shaped head that is used to support the cue when the cue ball is out of reach at normal extension.

Rest head adaptor

An attachment that slips onto a conventional rest head to make a spider or just to give a slightly different bridge.

Hook rest

Identical to the normal rest, yet with a hooked metal end. It is used to set the rest around another ball. The hook rest is the most recent invention in snooker.

Spider

Similar to the rest but with an arch-shaped head; it is used to elevate and support the tip of the cue above the height of the cue-ball.

Swan (or swan-neck spider)

This equipment, consisting of a rest with a single extended neck and a fork-like prong at the end, is used to give extra cueing distance over a group of balls.

Triangle/Rack

The piece of equipment is used for gathering the red balls into the formation required for the break to start a frame.

Extended rest

Similar to the regular rest, but with a mechanism at the butt end which makes it possible to extend the rest by up to three feet.

Extended spider

A hybrid of the swan and the spider. Its purpose is to bridge over large packs of reds. Is less common these days in professional snooker but can be used in situations where the position of one or more balls prevents the spider being placed where the striker desires.

Half butt

Usually housed underneath the side of the table, the half butt is a combination of a table length rest and cue which is rarely used unless the cue ball needs to be struck in such a way that the entire length of the table is the actual obstacle.

Ball marker

A multi-purpose instrument with a 'D' shaped notch, which a referee can (1) place next to a ball, in order to mark the position of it. They can then remove the ball to clean it; (2) use to judge if a ball is preventing a colour from being placed on its spot; (3) use to judge if the cue ball can hit the extreme edge of a "ball on" when awarding a free ball (by placing it alongside the potentially intervening ball).

The Cloth

The cloth is usually a green baize with a directional nap. The nap will affect the direction of the cue ball depending on which direction the cue ball is shot and also on whether left or right side (spin) is placed on the ball. Even if the cue ball is hit in exactly the same way, the nap will cause a different effect depending on whether the ball is hit down table (towards the black ball spot) or up table towards the balk line. The cloth on a snooker table should never be vacuumed as this can destroy the nap, especially if the vacuum head has beater brushes. The best method is to brush the cloth in a straight line from the balk end to the far end. Multiple brush strokes are fine as long as they are are straight in direction (i.e. not across the table). Some table men will also then drag a dampened cloth wrapped around a short piece of board (like a two by four) to collect any remaining fine dust and help lay the nap down.

Notable players

See also: List of snooker players by number of ranking titles and List of snooker players with over 100 century breaks

In the professional era that began with Joe Davis in the 1930s and continues up until the present day, a relatively small number of players have succeeded at the top level.Reaching and maintaining a place amongst the snooker elite is a tough task, with the standards of the game being such that it requires many years of dedication and effort as well as natural ability.

Certain players have tended to dominate the sport through the decades. John Pulman is generally regarded as the principal player through the 1960s, Ray Reardon through the 1970s, Steve Davis through the 1980s and Stephen Hendry through the 1990s, winning 6 (1970, 1973–76 and 1978), 6 (1981, 1983, 1984 and 1987–89) and 7 (1990, 1992–96 and 1999) World Championships respectively. No one dominated in the 2000s, however Ronnie O'Sullivan winning the title on three occasions (2001, 2004 and 2008) and Mark Williams and John Higgins winning twice (2000, 2003 and 2007, 2009 respectively). Higgins has four world titles in total, having won his first title in 1998 and his fourth in 2011. Last successful title defence was in 1996 when Hendry won the sixth of his seven titles (and 5th in a row).




 

 

1/26/2012

Running

Running

"Runner" redirects here. For other uses, see Runner (disambiguation).
This article is about the type of locomotion in humans. For running in horses, see Horse gait. For locomotion in dogs, see Gait (dog). For general locomotion, see Gait. For other uses, see Running (disambiguation).

Running is a means of terrestrial locomotion allowing humans and other animals to move rapidly on foot. It is simply defined in athletics terms as a gait in which at regular points during the running cycle both feet are off the ground. This is in contrast to walking, where one foot is always in contact with the ground, the legs are kept mostly straight and the center of gravity vaults over the legs in an inverted pendulum fashion. A characteristic feature of a running body from the viewpoint of spring-mass mechanics, is that changes in kinetic and potential energy within a stride occur simultaneously, with energy storage accomplished by springy tendons and passive muscle elasticity.The term running can refer to any of a variety of speeds ranging from jogging to sprinting.

The ancestors of mankind developed the ability to run for long distances about four and a half million years ago[citation needed], probably in order to hunt animals. Competitive running grew out of religious festivals in various areas. Records of competitive racing date back to the Tailteann Games in Ireland in 1829 BCE, while the first recorded Olympic Games took place in 776 BCE.

Running
Running motion.

History

It is thought that human running evolved at least four and a half million years ago out of the ability of the ape-like Australopithecus, an early ancestor of humans, to walk upright on two legs.The scientists, Dennis Bramble and Daniel Lieberman, have put forward a theory that early man developed as an endurance runner in order to hunt animals, and that human features such as the nuchal ligament, abundant sweat glands, the Achilles tendons, big knee joints and muscular glutei maximi, were a response to that running development.

Competitive running grew out of religious festivals in various areas such as Greece, Egypt, Asia, and the Rift Valley in Africa. The Tailteann Games, an Irish sporting festival in honour of the goddess Tailtiu, dates back to 1829 BCE, and is one of the earliest records of competitive running. The origins of the Olympics are shrouded in myth, though the first recorded game took place in 776 BCE.

Motion

Humans leap from one leg to the other while running. Each leap raises the center of gravity during take-off and lowers it on landing as the knee bends to absorb the shock. At mid arc, both feet are momentarily off the ground. This continual rise and fall of bodyweight expends energy opposing gravity and absorbing shock during take-off and landing. Running on a track requires more energy than walking to cover the same distance due to air resistance at higher speeds. As reported by Hall et al. males on a track running at a pace of 6.3 mph use 1.20 times as much energy to travel the same distance as walking at a pace of 3.15 mph, but on a treadmill running 6.3 mph uses just 1.01 times as much energy to travel the same distance as walking at 3.15 mph. Therefore, running is less efficient than walking in terms of calories expended per unit distance, though it is faster.

In 2004, scientists at the University of Utah and Harvard University hypothesized that the ability of humans to sustain long-distance endurance running may have been instrumental in the evolution of the human form.

Lower body motion

Running is executed as a sequence of strides, which alternate between the two legs. Each leg's stride can be roughly divided into three phases: support, drive, and recovery. Support and drive occur when the foot is in contact with the ground. Recovery occurs when the foot is off the ground. Since only one foot is on the ground at a time in running, one leg is always in recovery, while the other goes through support and drive. Then, briefly, as the runner leaps through the air, both legs are in recovery. These phases are described in detail below.


Support

During the support phase, the foot is in contact with the ground and supports the body against gravity. The body's centre of mass is typically somewhere in the lower abdominal area between the hips. The supporting foot touches the ground slightly ahead of the point that lies directly below the body's centre of mass. The knee joint is at its greatest extension just prior to the support phase. When contact is made with the ground, the knee joint begins to flex, and the extent it flexes varies with running style. Stiff-legged running styles reduce knee flexion, and looser, or more dynamic, running styles increase it. As the supporting leg bends at the knee, the pelvis dips down on the opposite side. These motions absorb shock and are opposed by the coordinated action of several muscles. The pelvic dip is opposed by the tensor fasciae lataeilio-tibial band of the supporting leg, the hip abductor, and the abdominals and lower back muscles. The knee flexion is opposed by the Muscle contraction[clarification needed] eccentric contraction of the quadriceps muscle. The supporting hip continues to extend, and the body's centre of mass passes over the supporting leg. The knee then begins to extend, and the opposite hip rises from its brief dip. The support phase begins to transition into drive.
Drive

The support phase quickly transitions into the drive phase. The drive leg extends at the knee joint, and at the hips, such that the toe maintains contact with the ground as that leg trails behind the body. The foot pushes backward and also down, creating a diagonal force vector, which, in an efficient running style, is aimed squarely at the runner's centre of mass. Since the diagonal vector has a vertical component, the drive phase continues to provide some support against gravity and can be regarded as an extension of the support phase. During the drive, the foot may extend also, by a flexing of the soleus and gastrocnemius muscle in the calf. In some running styles, notably long-distance "shuffles" which keep the feet close to the ground, the ankle remains more or less rigid during drive. Because the knee joint straightens, though not completely, much of the power of the drive comes from the quadriceps muscle group, and in some running styles, additional power comes from the calves as they extend the foot for a longer drive. This motion is most exhibited in sprinting.

There has been much discussion about the exact nature of the drive phase, because it has now been shown scientifically that the quadriceps have no activity after the supporting phase; this has become known as the extensor paradox in running.[9] Essentially, the body automatically turns off the quadriceps after the body weight moves forward of its supporting foot. This has led to a hypothesis that there is no driving phase in running, and that the runner's own body weight is providing the propulsion during this time, essentially falling through a gravitational torque created as the general centres of mass of the runner is in a forward position from the supporting foot.
Recovery

When the driving toe loses contact with the ground, the recovery phase begins. During recovery, the hip flexes, which rapidly drives the knee forward. Much of the motion of the lower leg is driven by the forces transferred from the upper leg rather than by the action of the muscles. As the knee kicks forward, it exerts torque against the lower leg through the knee joint, causing the leg to snap upward. The degree of leg lift can be consciously adjusted by the runner, with additional muscle power. During the last stage of recovery, the hip achieves maximal flexion, and, as the lower leg rapidly unfolds, which it does in a passive way, the knee joint also reaches its greatest, though not full, extension. During this extension of the leg and flexion of the hip, the hamstring and gluteal muscles are required to stretch rapidly. Muscles which are stretched respond by contracting by a reflex action. Recovery ends when the foot comes into contact with the ground, transitioning again into the support phase.

Upper body motion

The motions of the upper body are essential to maintaining balance, and a forward motion for optimal running. They compensate for the motions of the lower body, keeping the body in rotational balance. A leg's recovery is matched by a forward drive of the opposite arm, and a leg's support and drive motions are balanced by backward movement of the opposite arm. The shoulders and torso are also involved. Because the leg drive is slower than the kick of recovery, the arm thrusting backward is slower also. The forward arm drive is more forceful and rapid.

The more force exerted by the lower body, the more exaggerated the upper body motions have to be to absorb the momentum. While it is possible to run without movements of the arms, the spine and shoulders will generally still be recruited. Using the arms to absorb the forces aids in maintaining balance at higher speed. Otherwise, optimal force would be hard to attain for fear of falling over.

Most of the energy expended in running goes to the compensating motions, and so considerable gains in running speed as well as economy can be made by eliminating wasteful or incorrect motions. For instance, if the force vector in the drive phase is aimed too far away from the centre of mass of the body, it will transfer an angular momentum to the body which has to be absorbed.

The faster the running, the more energy has to be dissipated through compensating motions throughout the entire body. This is why elite sprinters have powerful upper body physiques. As the competitive distance increases, there is a rapid drop in the upper body and overall muscle mass typically exhibited by the people who compete at a high level in each respective event. Long distance runners typically have lean muscles.
Elements of good running technique

Upright posture and a slight forward lean

Leaning forward places a runner's center of mass on the front part of the foot, which avoids landing on the heel and facilitates the use of the spring mechanism of the foot. It also makes it easier for the runner to avoid landing the foot in front of the center of mass and the resultant braking effect. While upright posture is essential, a runner should maintain a relaxed frame and use his/her core to keep posture upright and stable. This helps prevent injury as long as the body is neither rigid nor tense. The most common running mistakes are tilting the chin up and scrunching shoulders.[citation needed]

Stride rate and types

Exercise physiologists have found that the stride rates are extremely consistent across professional runners, between 185 and 200 steps per minute. The main difference between long- and short-distance runners is the length of stride rather than the rate of stride.

During running, the speed at which the runner moves may be calculated by multiplying the cadence (steps per second) by the stride length. Running is often measured in terms of pace in minutes per mile or kilometer. Fast stride rates coincide with the rate one pumps one's arms. The faster one's arms move up and down, parallel with the body, the faster the rate of stride. Different types of stride are necessary for different types of running. When sprinting, runners stay on their toes bringing their legs up, using shorter and faster strides. Long distance runners tend to have more relaxed strides that vary.
Running injuries

Because of its high-impact nature, many injuries are associated with running. They include "runner's knee" (pain in the knee), shin splints, pulled muscles (especially the hamstring), twisted ankles, iliotibial band syndrome, plantar fasciitis, Achilles tendinitis, and stress fractures.[citation needed] Repetitive stress on the same tissues without enough time for recovery or running with improper form can lead to many of the above. Runners generally attempt to minimize these injuries by warming up before exercise, focusing on proper running form, performing strength training exercises, eating a well balanced diet, allowing time for recovery, and "icing" (applying ice to sore muscles or taking an ice bath).[citation needed]

Foot blisters are also common among runners. Specialized socks greatly help to prevent blisters.

Another common, running-related injury is chafing, caused by repetitive rubbing of one piece of skin against another, or against an article of clothing. One common location for chafe to occur is the runner's upper thighs. The skin feels coarse and develops a rash-like look. A variety of deodorants and special anti-chafing creams are available to treat such problems. Chafe is also likely to occur on the nipple.


A cold bath is a popular treatment of subacute injuries or inflammation, muscular strains, and overall muscular soreness, but its efficacy is controversial. Some claim that for runners in particular, ice baths offer two distinct improvements over traditional techniques.[who?] First, immersion allows controlled, even constriction around all muscles, effectively closing microscopic damage that cannot be felt and numbing the pain that can. One may step into the tub to relieve sore calves, quads, hams, and connective tissues from hips to toes will gain the same benefits, making hydrotherapy an attractive preventive regimen. Saint Andrew's cross-country coach John O’Connell, a 2:48 masters marathoner, will hit the ice baths before the ibuprofen. "Pain relievers can disguise injury", he warns. "Ice baths treat both injury and soreness." The second advantage involves a physiological reaction provoked by the large amount of muscle submerged. Assuming one has overcome the mind's initial flight response in those first torturous minutes, the body fights back by invoking a "blood rush". This rapid transmission circulation flushes the damage-inflicting waste from the system, while the cold water on the outside preserves contraction. Like an oil change or a fluid dump, the blood rush revitalizes the very areas that demand fresh nutrients.

Some runners may experience injuries when running on concrete surfaces. The problem with running on concrete is that the body adjusts to this flat surface running and some of the muscles will become weaker, along with the added impact of running on a harder surface. Therefore it is advised to change terrain occasionally – such as trail, beach, or grass running. This is more unstable ground and allows the legs to strengthen different muscles. Runners should be wary of twisting their ankles on such terrain. Running downhill also increases knee stress and should therefore be avoided. Reducing the frequency and duration can also prevent injury.

Another injury prevention method common in the running community is stretching. Stretching is often recommended as a requirement to avoid running injuries, and it is almost uniformly performed by competitive runners of any level. Recent medical literature, however, finds mixed effects of stretching prior to running. One study found insufficient evidence to support the claim that stretching prior to running was effective in injury prevention or soreness reductionAnother, however, has demonstrated that stretching prior to running increases injuries, while stretching afterwards actually decreases them. The American College of Sports Medicine recommends that all stretching be done after exercise because this is when the muscles are most warmed up and capable of increasing flexibility. Recent studies have also shown that stretching will reduce the amount of strength the muscle can produce during that training session.

Barefoot running has been promoted as a means of reducing running related injuries though this position on barefoot running remains controversial and a majority of professionals advocate the wearing of appropriate shoes as the best method for avoiding injury.

Recent studies have shown that runners do not have more osteoarthritis than people who do not run.

Benefits of running

While there is the potential for injury in running (just as there is in any sport), there are many benefits. Some of these benefits include potential weight loss, improved cardiovascular and respiratory health (reducing the risk of cardiovascular and respiratory diseases), improved cardiovascular fitness, reduced total blood cholesterol, strengthening of bones (and potentially increased bone density), possible strengthening of the immune system and an improved self esteem and emotional state. Running, like all forms of regular exercise, can effectively slow or reverse the effects of aging.

Running can assist people in losing weight, staying in shape and improving body composition. Running increases your metabolism. Different speeds and distances are appropriate for different individual health and fitness levels. For new runners, it takes time to get into shape. The key is consistency and a slow increase in speed and distance. While running, it is best to pay attention to how one's body feels. If a runner is gasping for breath or feels exhausted while running, it may be beneficial to slow down or try a shorter distance for a few weeks. If a runner feels that the pace or distance is no longer challenging, then the runner may want to speed up or run farther.[citation needed]

Running can also have psychological benefits, as many participants in the sport report feeling an elated, euphoric state, often referred to as a "runner's high".Running is frequently recommended as therapy for people with clinical depression and people coping with addiction. A possible benefit may be the enjoyment of nature and scenery, which also improves psychological well-being (see Ecopsychology#Practical benefits).

In animal models, running has been shown to increase the number of newly born neurons within the brain. This finding could have significant implications in aging as well as learning and memory.
Running events

Running is both a competition and a type of training for sports that have running or endurance components. As a sport, it is split into events divided by distance and sometimes includes permutations such as the obstacles in steeplechase and hurdles. Running races are contests to determine which of the competitors is able to run a certain distance in the shortest time. Today, competitive running events make up the core of the sport of athletics. Events are usually grouped into several classes, each requiring substantially different athletic strengths and involving different tactics, training methods, and types of competitors.

Running competitions have probably existed for most of humanity's history and were a key part of the ancient Olympic Games as well as the modern Olympics. The activity of running went through a period of widespread popularity in the United States during the running boom of the 1970's. Over the next two decades, as many as 25 million Americans were doing some form of running or jogging – accounting for roughly one tenth of the population.[27] Today, road racing is a popular sport among non-professional athletes, who included over 7.7 million people in America alone in 2002.

Limits of speed

Footspeed, or sprint speed, is the maximum speed at which a human can run. It is affected by many factors, varies greatly throughout the population, and is important in athletics and many sports.

The fastest human footspeed on record is 44.72 km/h (27.79 mph), seen during a 100 meter sprint (average speed between the 60th and the 80th meter) by Usain Bolt.

Events by type

Track running

Track running events are individual or relay events with athletes racing over specified distances on an oval running track. The events are categorised as sprints, middle and long-distance, and hurdling.

Road running

Road running takes place on a measured course over an established road (as opposed to track and cross country running). These events normally range from distances of 5 kilometers to longer distances such as half marathons and marathons, and they may involve large numbers of runners or wheelchair entrants.

Cross country running

Cross country running takes place over open or rough terrain. The courses used at these events may include grass, mud, woodlands, hills, flat ground and water. It is a popular participatory sport, and is one of the events which, along with track and field, road running, and racewalking, makes up the umbrella sport of athletics.

Events by distance

Sprints


Sprints are short running events in athletics and track and field. Races over short distances are among the oldest running competitions. The first 13 editions of the Ancient Olympic Games featured only one event – the stadion race, which was a race from one end of the stadium to the other.There are three sprinting events which are currently held at the Olympics and outdoor World Championships: the 100 metres, 200 metres, and 400 metres. These events have their roots in races of imperial measurements which were later altered to metric: the 100 m evolved from the 100 yard dash, the 200 m distances came from the furlong (or 1/8 of a mile), and the 400 m was the successor to the 440 yard dash or quarter-mile race.

At the professional level, sprinters begin the race by assuming a crouching position in the starting blocks before leaning forward and gradually moving into an upright position as the race progresses and momentum is gained. Athletes remain in the same lane on the running track throughout all sprinting events, with the sole exception of the 400 m indoors. Races up to 100 m are largely focused upon acceleration to an athlete's maximum speed.All sprints beyond this distance increasingly incorporate an element of endurance. Human physiology dictates that a runner's near-top speed cannot be maintained for more than thirty seconds or so as lactic acid builds up and leg muscles begin to be deprived of oxygen.

The 60 metres is a common indoor event and it an indoor world championship event. Other less-common events include the 50 metres, 55 metres, 300 metres and 500 metres which are used in some high and collegiate competitions in the United States. The 150 metres, though rarely competed, has a star-studded history: Pietro Mennea set a world best in 198Olympic champions Michael Johnson and Donovan Bailey went head-to-head over the distance in 1997, and Usain Bolt improved Mennea's record in 2009.

Middle distance

Main article: Middle distance running

Middle distance running events are track races longer than sprints up to 3000 metres. The standard middle distances are the 800 metres, 1500 metres and mile run, although the 3000 metres may also be classified as a middle distance event. The 880 yard run, or half mile, was the forebear to the 800 m distance and it has its roots in competitions in the United Kingdom in the 1830s.The 1500 m came about as a result of running three laps of a 500 m track, which was commonplace in continental Europe in the 1900s.
Long distance
Marathon
Ultrarunning
Multiday running

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