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Diving
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Diving

Diving has several meanings: plunging deliberately or acrobatically into water, swimming while under water, and using underwater breathing apparatus (such as when scuba diving or surface supplied diving).

Species of amphibious animals such as marine mammals and some seabirds dive to catch their prey underwater. Items of marine equipment like submarines and remotely operated vehicles are said to dive when they descend in the water.

Competitive diving

When people dive in the first sense, they deliberately enter a body of water by jumping in, usually in a posture that minimises drag on entry. Arms are stretched forwards parallel to straightened legs and torso.

Competitive swimmers enter the water by diving from a set height above a specially constructed pool. Dives are performed either from springboards — long, flexible planks that bend as the divers repeatedly jump on the end of the board to gain height and speed before diving — or from rigid platforms of greater height. In elite competition, there are two springboard height competitions, at 1 metre and 3 metres; and a platform competition at 10 metres.

Such divers may perform a variety of dives, making somersaults and twists in various orientations and from different starting positions (including platform dives from an initial handstand). Divers are judged on whether 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 (less being better). The raw score is then multiplied by a difficulty factor, derived from the number of movements attempted. The diver with the highest total score after a sequence of dives (usually eight in elite competition) is declared the winner.

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, including strength, flexibility, and kinaesthetic judgment.

Synchronized diving was adopted as an Olympic sport in 2004. In this event, two divers form a team and attempt to perform identical dives simultaneously. This is an impressive spectacle, and requires great co-ordination between the team-mates.

Recreational diving

The ability to dive and swim 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 with or without breathing apparatus.

Learning to swim underwater

Assuming that you can swim on the surface, the main obstacle to diving is likely to be the psychological barrier of immersing your head. To overcome this, try hard to keep your eyes open while under the water. Don't be afraid of water getting into your eyes; although chlorinated water can sting, it is not harmful. (Salt water is less irritating.) Your eyes, nose and ears will become accustomed to immersion; plugs and goggles are advisable when there is a risk of infection, for long periods of training, or for competitive swimming.

The crucial step in gaining underwater mobility is adopting a suitable posture. To do this, first try to reach an object on the floor of the pool (or other body of water) that is within your depth. It will be difficult to reach from an upright posture. To get your hands to the object, jump up, bend your body well forward, throw your feet in the air, and try to reach the object, head foremost.

The next exercise might be to swim a few metres towards the object on the surface, and then dive for it. It is difficult at first to get the chest below the surface; but if your legs are thrown well up in the air, their weight will force your body downwards. This is surface diving (also known as a jackknife).

Swimming underwater should follow quite naturally given some practice. It is largely a matter of maintaining a slightly inverted posture so as to counteract the natural buoyancy of the lungs. Strokes used in surface swimming must be adapted somewhat, and some arm movements (such as the crawl) cannot be used.

Learning to dive into water

Diving in this sense is not as difficult as it looks; again the main barrier is psychological, as diving head-first into the surface seems likely to hurt. It does, but only if the water is entered with a large splash. For safety reasons, diving should always be done into deep water and without goggles, which can damage the eyes.

It is best to start by entering some water where the surface is close to or level with the edge. Stoop down until you are nearly double, put your hands together over your head, lean over until they nearly touch the surface, and try to glide, rather than fall, into the water. With practise the height of entry can be increased. Next, you can try taking short run, and leaping head first into the water.

To make a clean entry, you should keep your body, arms, and legs quite stiff, and in a straight line. Tuck your head in so that your hands break the surface in front of it.


See also: scuba diving, snorkeling, free diving.

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