Diving (sport): Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
No edit summary
No edit summary
Line 1: Line 1:
{{Refimprove|date=April 2008}}
[[Image:[[Image:Example.jpg]]'''Bold text''']]{{Refimprove|date=April 2008}}


{{two other uses|the sport of jumping into water, often acrobatically|swimming below the surface of the water|underwater diving||Dive}}
{{two other uses|the sport of jumping into water, often acrobatically|swimming below the surface of the water|underwater diving||Dive}}

Revision as of 22:14, 10 October 2008

[[Image:Bold text]]

Template:Two other uses

Arvid Spångberg (1908 Summer Olympics)
A man dives into the Great South Bay of Long Island.

Diving refers to the sport of performing acrobatics whilst jumping or falling into water from a platform or springboard of a certain height. Diving is an internationally-recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a common recreational pastime in places where swimming is popular.

While not a particularly popular participant sport, diving is one of the more popular Olympic sports with spectators. Successful competitors possess many of the same characteristics as gymnasts and dancers, including strength, flexibility, kinaesthetic judgment and air awareness.

Diving tower at the 2008 Euros

In the recent past, the success and prominence of Greg Louganis led to American strength internationally. More recently, the greatest diving nation has been China, which came to prominence several decades ago when the sport was revolutionized by national coach Liang Boxi and after intense study of the dominant Louganis. China has lost few world titles since. Other powers are generally those which import Chinese coaches, including Australia and Canada.

Competitive diving

Competitive Springboard Diving
File:10MeterTower.jpg
Competitive Platform Diving

Most diving competitions consist of three disciplines: 1m and 3m springboards, and the platform. Competitive athletes are divided by gender, and often by age groups as well. In platform events, competitors are allowed to perform their dives on either the five, seven and a half (generally just called seven) or ten meter towers. In major diving meets, including the Olympic Games and the World Championships, platform diving is from the 10 meter height.

Divers must perform a set number of dives according to various established requirements, including somersaults and twists in various directions and from different starting positions. Divers are judged on whether and how well they completed all aspects of the dive, the conformance of their body to the requirements of the nominated dive, and the amount of splash created by their entry to the water. Theoretically, a score out of ten is supposed to be broken down into three points for the takeoff, three for the flight, and three for the entry, with one more available to give the judges flexibility.

The raw score is multiplied by a difficulty factor, derived from the number and combination of movements attempted. The diver with the highest total score after a sequence of dives is declared the winner.

Synchronized diving

Synchronized diving was adopted as an Olympic sport in 2000. In this event, two divers form a team and attempt to perform dives simultaneously. The dives are usually identical; however, sometimes the dives may be opposites, in what is called a pinwheel. In these events, synchronicity is valued as highly as technical skill.

Scoring the dive

Ultimately, the judges' scores given on each dive are subjective. However, there are specific rules governing how a dive is supposed to be scored. Usually a score factors three elements of the dive: the approach, the flight, and the entry. The primary factors affecting the scoring are: (1) the platform selected (10-meter, 7.5-meter, or 5-meter), (2) if a hand-stand is required, the length of time and quality of the hold, (3) the height of the diver at the apex of the dive, with extra height resulting in a higher score, (4) the distance of the diver from the diving apparatus throughout the dive (a diver must not be dangerously close, should not be too far away, but should ideally be within 2 feet (0.61 m) of the platform), (5) the properly defined body position of the diver according to the dive being performed, including pointed toes and feet touching at all times, (6) the proper amounts of rotation and revolution upon completion of the dive and entry into the water, and (7) angle of entry (a diver should enter the water straight, without any angle). Many judges award divers for the amount of splash created by the diver on entry, with less splash resulting in a higher score.

To reduce the subjectivity of scoring in major meets, panels of five or seven judges are assembled. In the case where five judges are assembled, the highest and lowest scores are discarded and the middle three are summed and multiplied by the DD (Degree of Difficulty -- determined from a combination of the moves undertaken, in which position and from what height). In major international events, seven judges are assembled. In these circumstances, the highest and lowest scores are again discarded and the middle five are summed, then ratioed by 3/5, and multiplied by the DD, so as to provide consistent comparison with 5-judge events. Accordingly, it is extremely difficult for one judge to manipulate scores.

There is a general misconception about scoring and judging. In serious meets, the absolute score is somewhat meaningless. It is the relative score, not the absolute score that wins meets. Accordingly, good judging implies consistent scoring across the dives. Specifically, if a judge consistently gives low scores for all divers, or consistently gives high scores for the same divers, the judging will yield fair relative results and will cause divers to place in the correct order. However, absolute scores have significance to the individual divers. Besides the obvious instances of setting records, absolute scores are also used for rankings and qualifications for higher level meets.

Competitive strategy

To win dive meets, divers create a dive list in advance of the meet. To win the meet the diver must accumulate more points than other divers. Usually simple dives with low DDs will look good to spectators but will not win meets. The competitive diver will attempt the highest DD dives possible with which they can achieve consistent, high scores. If divers are scoring 8 or 9 on most dives, it may be a sign of their extreme skill, or it may be a sign that their dive list is not competitive, and they may lose the meet to a diver with higher DDs and lower scores.

In competition, divers must submit their lists beforehand, and past a certain deadline (usually when the event is announced shortly before it begins) they cannot change their dives under any circumstances. If they fail to perform the dive announced, even if they physically cannot execute the dive announced, even if they perform a more difficult dive, they will receive a score of zero. Under exceptional circumstances, a redive may be granted, but these are exceedingly rare (usually for very young divers just learning how to compete, or if some event outside the diver's control has caused them to be unable to perform).

There are some American meets which will allow changes of the position of the dive even after the dive has been announced immediately before execution, but these are an exception to the rules generally observed internationally.

Generally, NCAA rules allow for dives to be changed while the diver is on the board, but the diver must request the change directly after the dive is announced. This applies especially in cases where the wrong dive is announced. If the diver pauses during his or her hurdle to ask for a change of dive, it will be declared a balk and the change of dive will not be permitted.

Under FINA law, no dive may be changed after the deadline for the dive-sheet to be submitted (generally a period ranging from one hour to 24 hours, depending on the rulings made by the event organiser.

It is the diver's responsibility to ensure that the dive-sheet is filled in correctly, and also to correct the referee or announcer before the dive if they describe it incorrectly. If a dive is performed which is as submitted but not as (incorrectly) announced, it is declared failed and scores zero according to a strict reading of the FINA law. But in practice, a re-dive would usually be granted in these circumstances.

Diving and other sports

Divers do not consider themselves swimmers. While each sport shares a pool, and may compete side by side when doing so for their schools, the two sports are very different. Swimming is a full body exercise with emphasis on upper body strength and speed, diving is a full body exercise with emphasis on grace and execution; swimmers most frequently suffer overuse injuries, divers most frequently suffer impact injuries or strains.

The sister sport of diving is gymnastics. Many divers begin their training as gymnasts, and switch sports for one reason or another. Two of the most common are that they simply prefer diving, or that they develop a chronic injury that makes continuing gymnastics impossible. Gymnastics provides young divers with unique skills that help them perform complex and risky dives, but there are downsides; some habits developed in gymnastics can interfere with the correct technique of diving.

Governance

Diving is the best! The global governing body of diving is FINA, which also governs swimming, synchronized swimming, water polo and open water swimming. Almost invariably, at national level, diving shares a governing body with the other aquatic sports.

This is frequently a source of political friction as the committees are naturally dominated by swimming officials who do not necessarily share or understand the concerns of the diving community. Divers often feel, for example, that they do not get adequate support over issues like the provision of facilities. Other areas of concern are the selection of personnel for the specialised Diving committees and for coaching and officiating at events, and the team selection for international competitions.

There are sometimes attempts to separate the governing body as a means to resolve these frustrations, but they are rarely successful. For example, in the UK the Great Britain Diving Federation was formed in 1992 with the intention of taking over the governance of Diving from the ASA (Amateur Swimming Association). Although it initially received widespread support from the diving community, the FINA requirement that international competitors had to be registered with their National Governing Body was a major factor in the abandonment of this ambition a few years later.

Since FINA refused to rescind recognition of the ASA as the British governing body for all aquatic sports including diving, this meant that the elite divers had to belong to ASA affiliated clubs in order to be eligible for selection to international competition.

In the United States scholastic diving is almost always part of the school’s swim team. Diving is a separate sport in Olympic and Club Diving. The NCAA will separate diving from swimming in special diving competitions after the swim season is completed.

Safety

A sign prohibiting diving at a beach in Kirkland, Washington

There is a general perception of diving as being a dangerous activity, and this has contributed to the decline in availability of facilities. In fact, despite the apparent risk, the statistical incidence of injury in supervised training and competition is extremely low.[citation needed]

The majority of accidents that are classified as 'diving-related' are incidents caused by individuals jumping from structures such as bridges or piers into water of inadequate depth. Because of this many beaches and pools prohibit diving in shallow waters or when a lifeguard is not on duty.

After an incident in Washington state in 1993, most US and other pool builders are reluctant to equip a residential swimming pool with a diving springboard, so home diving pools are much less common these days. In the incident 14-year-old Shawn Meneely made a "suicide dive" (his hands at his sides - so his head hit the bottom first) in a private swimming pool and was seriously injured (tetraplegic). Family lawyer Fred Zeder successfully sued the diving board manufacturer, the pool builder, and the National Spa & Pool Institute over the inappropriate depth of the pool.[1] The NSPI had specified a minimum depth of 7 ft 6 in (2.55m) which proved to be insufficient in the above case. The pool into which Meneelly dove was not constructed exactly to the published standards. The standards had changed after the diving board was installed on the non-compliant pool by the homeowner. But the courts held that the pool "was close enough" to the standards to hold NSPI liable. The multi-million dollar lawsuit was eventually settled in 2001 for $6,600,000USD ($US8,000,000 after interest was added) in favor of the plaintiff. [2] The NSPI was held to be liable, and was financially strained by the case. It filed twice for Chapter 11 bankruptcy protection and was successfully reorganized into a new swimming pool industry association.[1]

Within competitive diving, FINA takes regulatory steps to ensure that athletes are protected from the inherent dangers of the sport. For example, they impose restrictions according to age on the heights of platforms which divers may compete on.

Group D (11 & under): 5m

Group C (12/13 year): 5m & 7.5m

Group B (14/15 year): 5m, 7.5m & 10m

Group A (16/18 year): 5m, 7.5m & 10m

Group D divers have only recently been allowed to compete tower at all. In the past, the age group could compete only springboard, in order to discourage young children from taking on the greater risks of tower diving. Group D tower was introduced to counteract the phenomenon of coaches pushing young divers to compete in higher age categories, thus putting them at even greater risk.

However, some divers may safely dive in higher age categories in order to dive on higher platforms. Usually this occurs when advanced Group C divers wish to compete on the 10m.

Dive groups

A male diver performs a reverse from a 1 meter springboard in the tuck position

There are six "groups" into which dives are classified: Forward, Back, Inward, Reverse, Twist, and Armstand. The latter applies only to Platform competitions, whereas the other five apply to both Springboard and Platform.

  • In the Forward Group (Group 1), the diver takes off facing forward and rotates forward
  • In the Back Group (2), the diver takes off with their back to the water and rotates backward
  • In the Reverse Group (3), the diver takes off facing forward and rotates backward
  • In the Inward Group (4), the diver takes off with their back to the water and rotates forward
  • Any dive incorporating an axial twisting movement is in the Twist group (5).
  • Any dive commencing from a handstand is in the Armstand group (6).(only on platform)

Dive positions

During the flight of the dive, one of the four positions may be specified:

  • Straight - with no bend at the knees or hips
  • Pike - with knees straight but a tight bend at the hips
  • Tuck - body folded up in a tight ball, hands holding the shins and toes pointed.
  • Free - Some sequence of the above positions.

These positions are referred to by the letters A, B,C and D respectively.

Dive numbers

In competition, the dives are referred to by a schematic system of three- or four-digit numbers. The letter to indicate the position is appended to the end of the number.

The first digit of the number indicates the dive group as defined above.

For groups 1 to 4, the number consists of three digits and a letter of the alphabet. The third digit represents the number of half-somersaults. The second digit is either 0 or 1; with 1 signifying a "flying" variation of the basic movement: ie the first half somersault is performed in the straight position, and then the piked or tucked shape is assumed.

For example:

  • 101A - Forward Dive Straight
  • 203C - Back one-and-a-half somersaults, tuck
  • 307C - Reverse three-and-a-half somersaults, tuck
  • 113B - Flying forward one-and-a-half somersaults, pike

For Group 5, the dive number has 4 digits. The second digit indicates the group (1-4) of the underlying movement; the third digit indicates the number of half-somersaults, and the fourth indicates the number of half-twists.

For example:

  • 5211A - Back dive, half twist, straight position.
  • 5337D - Reverse one and a half somersaults with three and a half twists, in the Free position.

For Group 6 - Armstand - the dive number has either three, four or five digits: Three digits for dives without twist and four for dives with twists.

In non-twisting armstand dives, the second digit indicates the direction of rotation (0 = no rotation, 1 = forward, 2 = backward, 3 = reverse, 4 = inward) and the third digit indicates the number of half-somersaults. Inward-rotating armstand dives have never been performed, and are generally regarded as physically impossible.

For example:

  • 600A - Armstand dive straight
  • 612B - Armstand forward somersault pike
  • 624C - Armstand back double somersault tuck

For twisting Armstand dives, the dive number again has 4 digits, but rather than beginning with the number 5, the number 6 remains as the first digit, indicating that the "twister" will be performed from an Armstand. The second digit indicates the direction of rotation - as above, the third is the number of half-somersaults, and the fourth is the number of half-twists:

e.g. 6243D - armstand back double-somersault with one and a half twists in the free position

All of these dives come with DD (degree of difficulty) this is an indication of how difficult/complex a dive is. The score that the dive receives is multiplied by the DD (also known as tariff) to give the dive a final score. Before a diver competes they must decide on a "list" this is a number of optional dives and compulsory dives. The optionals come with a DD limit. this means that a diver must select X number of dives and the combined DD limit must be no more than the limit set by the competition/organisation etc.

Until the mid 1990s the tariff was decided by the FINA diving committee, and divers could only select from the range of dives in the published tariff table. Since then, the tariff is calculated by a formula based on various factors such as the number of twist and somersaults, the height, the group etc., and divers are free to submit new combinations.

Mechanics of diving

Tomb of the Diver, Paestum, Italy, a Greek fresco dated 470 BC

At the moment of take-off, two critical aspects of the dive are determined, and cannot subsequently be altered during the execution. One is the trajectory of the dive, and the other is the magnitude of the angular momentum.

The speed of rotation - and therefore the total amount of rotation - may be varied from moment to moment by changing the shape of the body, in accordance with the law of conservation of angular momentum.

The center of mass of the diver follows a parabolic path in free-fall under the influence of gravity (ignoring the effects of air resistance, which are negligible at the speeds involved).

Trajectory

Since the parabola is symmetrical, the travel away from the board as the diver passes it is twice the amount of the forward travel at the peak of the flight. Excessive forward distance to the entry point is penalized when scoring a dive, but obviously an adequate clearance from the diving board is essential on safety grounds.

The greatest possible height that can be achieved is desirable for several reasons:

  • The height attained is itself one of the factors that the judges will reward.
  • A greater height gives a longer flight time and therefore longer to execute the moves.
  • For any given clearance when passing the board, the forward travel distance to the entry point will be less for a higher trajectory.

Control of rotation

The magnitude of angular momentum remains constant throughout the dive, but since

angular momentum = rotational velocity × moment of inertia,

and the moment of inertia is larger when the body has an increased radius, the speed of rotation may be increased by moving the body into a compact shape, and reduced by opening out into a straight position.

Since the tucked shape is the most compact, it gives the most control over rotational speed, and dives in this position are easier to perform. Dives in the straight position are hardest, since there is almost no scope for altering the speed, so the angular momentum must be created at take-off with a very high degree of accuracy. (A small amount of control is available by moving the position of the arms and by a slight hollowing of the back).

Notice that the opening of the body for the entry does not stop the rotation, but merely slows it down. The vertical entry achieved by expert divers is largely an illusion created by starting the entry slightly short of vertical, so that the legs are vertical as they disappear beneath the surface. A small amount of additional tuning is available by 'entry save' techniques, whereby underwater movements of the upper body and arms against the viscosity of the water affect the position of the legs.

Twisting

A twisting dive performed from a 1 meter springboard.

Dives with multiple twists and somersaults are some of the most spectacular movements, as well as the most challenging to perform.

The rules state that twisting 'must not be generated manifestly on take-off'. Consequently, divers must use some of the somersaulting angular momentum to generate twisting movements. The physics of twisting can be explained by looking at the components of the angular momentum vector.

As the diver leaves the board, the total angular momentum vector is horizontal, pointing directly to the left for a forward dive for example. For twisting rotation to exist, it is necessary to tilt the body sideways after takeoff, so that there is now a small component of this horizontal angular momentum vector along the body's long axis. The tilt can be seen in the photo.

The tilting is done by the arms, which are outstretched to the sides just before the twist. When one arm is moved up and the other is moved down (like turning a big steering wheel), the body reacts by tilting to the side, which then begins the twisting rotation. At the completion of the required number of twist rotations, the arm motion is reversed (the steering wheel is turned back), which removes the body's tilt and stops the twisting rotation.

An alternative explanation is that the moving arms have precession torque on them which set the body into twisting rotation. Moving the arms back produces opposite torque which stop the twisting rotation.

Entry

The rules state that the body should be vertical, or nearly so, for entry. The arms must be beside the body for feet-first dives and extended forwards in line for "head-first" dives. It used to be common for the hands to be interlocked with the fingers extended towards the water, but a different technique has become favoured during the last few decades. Now the usual practice is for one hand to grasp the other with palms down to strike the water with a flat surface (the so-called "rip entry"). This creates a vacuum between the hands, arms and head which with a vertical entry will pull down and under any splash until deep enough to have minimal effect on the surface of the water. Once a diver is completely under the water they may choose to roll or scoop in the same direction their dive was rotating to pull the splash away from the channel which they have just created.

Template:Globalize/Eng

United States diving

Divers can compete in several venues, which may each have age and experience limitations.

Summer diving

In the United States, summer diving is usually limited to one meter diving at community or country club pools. Some pools organize to form intra-pool competitions. These competitions are usually designed to accommodate all school-age children. One of the largest and oldest competitions in the United States is found in the Northern Virginia area where 47 pools compete against each other every summer (with over 380 divers in NVSL's "Cracker Jack" meet).

High school diving

In the United States scholastic diving at the high school level is usually limited to one meter diving (But some schools use 3 meter springboards.). Scores from those one meter dives contribute to the swim team's overall score.

Club diving

In the United States, pre-college divers interested in three meter or tower diving should consider a club sanctioned by USA Diving or AAU Diving. There is a group called Future Championship. Top club divers are usually called "junior Olympic", or JO divers. JO divers compete for spots on national teams. Divers over the age of 19 years of age cannot compete in these events as a JO diver.

USA Diving sanctions one East-West one and three meter event in the winter time with an Eastern champion and Western champion determined. In the summer USA Diving sanctions a national event with tower competitions offered.

AAU Diving sanctions one national event per year in the summer. AAU competes on the one, three, and tower to determine the All-American team.

College diving

The University of Houston's CRWC Natatorium is home to the United States' largest collegiate swimming pool

In the United States scholastic diving at the college level requires one and three meter diving. Scores from the one and three meter competition contribute to the swim team's overall meet score. College divers interested in tower diving may compete in the NCAA separate from swim team events. NCAA Divisions II and III do not usually compete platform; if a diver wishes to compete platform in college, he or she must attend a Division I school. Each of the different divisions also has different rules on number of dives in each competition. Division II schools compete with 10 dives in competition whereas Division III schools compete with 11. Division I schools only compete with 6 dives in competition.

A number of colleges and universities offer scholarships to men and women who have competitive diving skills. These scholarships are usually offered to divers with age-group or club diving experience.

The NCAA limits the number of years a college student can represent any school in competitions. The limit is four years, but could be less under certain circumstances.

Master Diving

In the United States divers who continue diving past their college years can compete in Master Diving programs. Master diving programs are frequently offered by college or club programs.

Masters' Diving events are normally conducted in age-groups of 5 or 10 years, and attract competitors of a wide range of ages and experience (many, indeed, are newcomers to the sport); the oldest competitor in a Masters' Diving Championship was Viola Krahn, who at the age of 101 was the first person in any sport, male or female, anywhere in the world, to compete in an age-group of 100+ years in a nationally organized competition.

British diving

In Britain, diving competitions on all boards run throughout the year. National Masters' Championships are held two or three times per year.

Canadian diving

In Canada, elite competitive diving is regulated by DPC (Diving Plongeon Canada). The main competitive season runs from roughly February to July, although some competitions may be held in January or December, and many divers (particularly international level athletes) will train and compete year round.

Most provincial level competitions consist of events for 6 different age groups (Groups A, B, C, D, E, and Open) for both genders on each of the three board levels. These age groups roughly correspond to those standardized by FINA, with the addition of a youngest age group for divers 9 and under, Group E, which does not compete nationally (although divers of this age may choose to compete Group D). The age group Open is so called because divers of any age, including over 18, may compete in these events, so long as their dives meet a minimum standard of difficulty.

Divers can qualify to compete at the age group national championships, or junior national championships, in their age groups as assigned by FINA up to the age of 18. This competition is held annually in July. Qualification is based on achieving minimum scores at earlier competitions in the season determined by DPC according to the results of the preceding year's national competition.

Divers older than 18, or advanced divers of younger ages, can qualify for the senior national championships, which are held twice each year, once roughly in March and once in June or July. Once again, qualification is based on achieving minimum scores at earlier competitions; in this case, within the 12 months preceding the national championships.

Famous divers

Non-competitive diving

Man and woman jumping off a cliff at Colliding Rivers, Glide, OR.

Diving is also popular as a non-competitive activity that is often simply done for pleasure or thrills. Such diving usually emphasizes the airborne experience, and the height of the dive, but does not emphasize what goes on once the diver enters the water. The ability to dive underwater can be a useful emergency skill, and is an important part of watersport and navy safety training. More generally, entering water from a height is an enjoyable leisure activity, as is underwater swimming.

A man jumping into Lake Michigan.

Such non-competitive diving can occur both indoors and outdoors. Outdoor diving typically takes place from cliffs or other rock formations either into fresh or salt water. However, man-made diving platforms are sometimes constructed in popular swimming destinations. Outdoor diving requires knowledge of the water depth and currents as conditions can be dangerous. Despite these risks the activity has proven to be very popular due to its thrilling nature.

See also

References

  1. ^ a b Brown, AmyJo (30 January 2004). "No Diving?". Pool & Spa News. Retrieved 2007-04-15.
  2. ^ Appeals Court State of WA, Docket Number:18036-1-III Title: Shawn Meneely, et al v.S. R. Smith,inc,. et al.

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Diving_(sport)&oldid=244457901"