skin diving

 

act of swimming freely underwater. It is done with the aid of a face mask, swimming fins for the feet, and either a snorkel breathing tube or scuba [acronym for self-contained underwater breathing apparatus] gear. The fins increase the propulsion and agility of the swimmer. Skin diving is used in scientific, commercial, and military activities and in recent years has gained enormous popularity as a beach sport. Free underwater swimming is not new, and as long ago as the 8th cent. B.C. Greek divers, unconnected to the surface by air hoses or lines, collected sponges and mollusks in depths as great as 100 ft (30 m). The Greeks and Romans employed underwater warriors, trained to hold their breath for long periods of time, to sabotage enemy fleets. In the Pacific islands natives have long practiced skin diving and spear fishing. Many improvements in skin-diving equipment were made during World War II, and the so-called frogmen of the U.S. and British navies played a vital role in operations. An important development of this period was scuba diving with an Aqua-lung (see diving, deep-sea). The scuba diver, with his greater mobility, has replaced in many areas of underwater activity the conventional sea diver who is encumbered by heavy equipment and limited by a lifeline and air hose. However, it is dangerous for a scuba diver to work below a 130-ft (40-m) depth, and although free dives have been made to more than 300 ft (91 m), conventional dress and equipment are generally used for deep descents.

Bibliography

See J. Strykowski, Diving for Fun (3d ed. 1971); H. Hass, Challenging the Deep (tr. 1973).

Free-diving is any of various aquatic activities that share the practice of breath-hold underwater diving. Examples include breathhold spearfishing, freedive photography, apnea competitions and, to a degree, snorkeling. The activity that garners the most public attention is competitive apnea, an extreme sport, in which competitors attempt to attain great depths, times or distances on a single breath without direct assistance of an underwater breathing apparatus.

Description

Freediving is a technique used with various aquatic activities. While in general all aquatic activities that include breath-hold diving might be classified as a part of freediving, some sports are more accepted than others. Examples of recognized freediving activities are (non-) competitive freediving, (non-) competitive spearfishing, freedive photography and mermaid shows. Less recognised examples of freediving include, but are not limited to, synchronised swimming, underwater rugby, underwater hockey, underwater hunting other than spearfishing and snorkeling. The discussion remains whether freediving is only a synonym for breath-hold diving or whether it describes a specific group of underwater activities. Freediving is often strongly associated with competitive breath-hold diving or Competitive Apnea. It is a sport in which competitors attempt to attain great depths, times, or distances on a single breath and without the assistance of breathing apparatus like SCUBA. The following remainder of this article will only discuss competitive freediving as an athletic sport.

Competitive freediving

Competitive freediving is currently governed by two world associations: AIDA International and CMAS. Most types of competitive freediving have in common that it is an individual sport based on the best individual achievement. An exception to this rule is the bi-annual World Championship for Teams, held by AIDA, where the combined score of the team members makes up the team's total points. There are currently nine disciplines used by official governing bodies and a dozen disciplines that are only practiced locally. In this article, the recognized disciplines of AIDA and CMAS will be described. All disciplines can be done by both men and women and, while done outdoors, no differences in the environment between records are recognized any longer. The disciplines of AIDA can be done both in competition and as a record attempt, with the exception of Variable Weight and No limits, which are both only done as record attempts. The following official disciplines are recognized by AIDA, CMAS, or both.

Pool disciplines

• Static Apnea is timed breath holding and is usually attempted in a pool. (AIDA)
• Dynamic Apnea with fins. This is underwater swimming in a pool for distance. For this discipline the athlete can choose whether to use bi-fins or the monofin. (AIDA), (CMAS)
• Dynamic Apnea without fins. This is underwater swimming in a pool for distance without any swimming aids like fins. (AIDA)

Depth disciplines

For all AIDA disciplines, the depth the athlete will attempt is announced before the dive. This is accepted practice for both competitions and record attempts.

• Constant Weight with fins. The athlete has to dive to the depth following a guide line that he or she is not allowed to actively use during the dive. The ‘constant weight’ ("poids constant") refers to the fact that the athlete is not allowed to drop the weights during the dive. Both bi-fins and mono-fin can be used during this discipline (AIDA).
• Constant Weight without fins follows the identical rules as Constant Weight with fins, except no swimming aids such as fins are allowed. This discipline is the youngest discipline within competitive freediving and is recognised by AIDA International since 2003.(AIDA)
• Free Immersion is the discipline in which the athlete uses the guideline to pull him or herself down to depth and back to the surface. It is known for its ease compared with the Constant Weight disciplines, while the athlete is still not allowed to release weights (AIDA).
• Variable Weight is a record discipline that uses a weighted sled for descent. Athletes return to the surface by pulling themselves up along a line or swimming while using their fins (AIDA).
• No Limits is a record discipline that allows the athlete to use any means of breath-hold diving to depth and return to the surface as long as a guideline is used to measure the distance. Most divers use a weighted sled to dive down and use an air-filled bag to return to the surface (AIDA).
• "The Cube" is also known as "Jump Blue" and is a discipline in which an athlete has to descend to 15 meters and swim as far as possible in a cubic form of 15 x 15 meters. (CMAS only)

Each organization has its own rules on recognizing an attempt. These can be found on the website from the respective organizations..

Physiology of free-diving

The human body has several adaptations under diving conditions, which stem from the mammalian diving reflex. These adaptations enable the human body to endure depth and lack of oxygen far beyond what would be possible without the reflex.

The adaptations made by the human body while underwater and at high pressure include:

• Bradycardia: Drop in heart pulse rate.
• Vasoconstriction: Blood vessels shrink. Blood stream directed away from limbs for the benefit of heart, lungs and brain.
• Splenic contraction: Releasing red blood cells carrying oxygen.
• Blood shift: Blood plasma fills up blood vessels in the lung and reduces residual volume. Without this adaptation, the human lung would shrink and wrap into its walls, causing permanent damage, at depths greater than 30 meters.

Training

Training for free diving can take many forms, many of them out of water.

One example is the apnea walk. This consists of a preparation "breathe-up", followed by a short (typically 1 minute) breath hold taken at rest. Without breaking the hold, the participant then initiates a walk for as far as they can, until it becomes necessary to breathe again. Athletes can do close to 400 meters in training this way.

This form of training is good for accustoming muscles to work under anaerobic conditions, and for tolerance to CO₂ build-up in the circulation. It is also easy to gauge progress, as increasing distance can be measured.

Before diving, untrained free divers may hyperventilate, resulting in a lower level of CO₂ in their lungs and bloodstream. This postpones the start of stimulation to the breathing centre of the brain, and thus delays the warning signals of running out of air. As the oxygen level of the blood is not increased by hyperventilation, this is very dangerous and may result in drowning. (For more detail refer to the articles shallow water blackout and deep water blackout.) Trained freedivers are well aware of this and will limit their immediate pre-dive breathing, typically to a maximum of two or three breaths taken slowly and deeply so as to maximize oxygen saturation whilst not depressing blood CO₂ levels. However this does not, of itself, eliminate the risk of deep or shallow water blackout and diving with a 'buddy' who remains observing at the surface is the standard practice.

Official world records as of September, 2007 (AIDA)

• Static Apnea
  • women: Natalia Molchanova (Russia), 8m00s
  • men: Tom Sietas (Germany), 9m08s

• Dynamic Apnea
  • women: Natalia Molchanova (Russia), 200 metres
  • men: Dave Mullins (New Zealand), 244 metres

• Dynamic Apnea, without fins
  • women: Natalia Molchanova (Russia), 149 metres
  • men: Stig Severinsen (Denmark), 186 metres

• Constant Weight
  • women: Mandy-Rae Cruickshank (Canada), -88 metres
  • men: Herbert Nitsch (Austria), -111 metres

• Constant Weight without fins
  • women: Natalia Molchanova (Russia), -55 metres
  • men: William Trubridge (New Zealand), -82 metres

• Free Immersion
  • women: Natalia Molchanova (Russia), -80 metres
  • men: Martin Štěpánek (Czech Republic), -106 metres

• Variable Weight
  • women: Tanya Streeter (Cayman Islands), -122 metres
  • men: Carlos Coste (Venezuela), -140 metres

• No limits
  • women: Tanya Streeter (Cayman Islands), -160 metres
  • men: Herbert Nitsch (Austria), -214 metres

Free-diving in fiction

• In the Canadian television series Corner Gas, the character Karen Pelly (Tara Spencer-Nairn) competed in static apnea, ranking fifth in Canada with a personal best of over six minutes.
• The Big Blue starring Rosanna Arquette, Jean Reno, and Jean Marc-Barr is a romance film about two world-class free-divers and is partly based on fact.
• Into The Blue starring Paul Walker, Jessica Alba, Scott Caan, and Ashley Scott. A group of divers find themselves in deep trouble with a drug lord after they come upon the illicit cargo of a sunken airplane.
• The Greater Meaning of Water (2007) Starring Justin Williford, Mark Brunetti, and Holly London. An independent film about competitive freediving focusing on the "zen of freediving".[1]
• In the computer game The Secret of Monkey Island, the main character, Guybrush Threepwood, boasts being able to hold his breath for ten minutes. Although not exactly free-diving, Guybrush ends up underwater in a certain point of the game, and dies if the player doesn't solve the puzzle in ten minutes.

Some famous competitive apnea divers

Agustín Di Francisco Anabel Briseno Audrey Mestre Ant Williams Bill Strömberg Carlos Coste Davide Carrera Deborah Andollo Dave Mullins Danai Varveri Enzo Maiorca Erez Beatus Eric Fattah Francisco "Pipin" Ferreras Giancarlo Bellingrath it:Gianluca Genoni

Guillaume Néry Herbert Nitsch Jacques Mayol Karol Meyer Loïc Leferme Lotta Ericsson Mandy-Rae Cruickshank Martin Štěpánek Natalia Molchanova Patrick Musimu Peter Pedersen Pierre Frolla

Ryuozo Shinomiya Sebastien Murat Stephane MIFSUD Stig Aavall Severinsen Tanya Streeter Tom Sietas Topi Lintukangas Umberto Pelizzari Walter Steyn William Trubridge William Winram Yasemin Dalkilic

See also

• Apnea
• Shallow water blackout
• Deep water blackout

External links

• AIDA - Association Internationale Pour Le Developpment De L'Apnee
• CMAS - Confederation Mondiale des activities subaquatiques
• APNEA MANIA, massive freedive info
• FREEDIVE CENTRAL - all about freedivers and competitions
• Aquatic Safety Research Group - Medical issues
• Apnea Academy- A global teaching organisation for underwater apnea - presided over by Umberto Pelizzari
• DeeperBlue.net- Popular website for discussion and news
• Freediving Introduction

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