Tuesday, November 30, 2010
History of Diving
* Diving is the sport of jumping or falling into water from a platform or springboard, sometimes while performing acrobatics. Diving is an internationally-recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a recreational pastime.
* Diving is one of the most popular Olympic sports with spectators. Competitors possess many of the same characteristics as gymnasts and dancers, including strength, flexibility, kinaesthetic judgment and air awareness.
* China 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. The success of Greg Louganis has led to American strength in diving internationally. Other noted countries in the sport include Italy, Australia and Canada.
Competitive springboard diving
Arvid Spångberg (1908 Summer Olympics)
* A man dives into the Great South Bay of Long Island
* Most diving competitions consist of three disciplines: 1m and 3m springboards, and the platform. Competitive athletes are divided by gender, and often by age group. 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 have to perform a set number of dives according to established requirements, including somersaults and twists. 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 dive, and the amount of splash created by their entry to the water. A possible score out of ten is 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.
* Synchronized diving was adopted as an Olympic sport in 2000. Two divers form a team and perform dives simultaneously. The dives are usually identical; however, sometimes the dives may be opposites, in what is called a pinwheel. In these events, the diving is judged both on the quality of execution and the synchronicity - in timing of take-off and entry, height and forward travel.
Scoring the dive
There are rules governing the scoring of a dive. Usually a score considers three elements of the dive: the approach, the flight, and the entry. The primary factors affecting the scoring are:
the platform selected (10 meter, 7.5 meter, or 5 meter)
1. if a hand-stand is required, the length of time and quality of the hold
2. the height of the diver at the apex of the dive, with extra height resulting in a higher score
3. 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)
4. the properly defined body position of the diver according to the dive being performed, including pointed toes and feet touching at all times
5. the proper amounts of rotation and revolution upon completion of the dive and entry into the water
6. 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 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. Often, 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 once past a deadline (usually when the event is announced or shortly before it begins) they cannot change their dives. If they fail to perform the dive announced, even if they physically cannot execute the dive announced or 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).
* 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.
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).
* 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 more time to execute maneuvers.
* for any given clearance when passing the board, the forward travel distance to the entry point will be less for a higher trajectory.