Bungee jumping

Not to be confused with reverse bungee.

Bungee jumping off the Victoria Falls Bridge in Zambia/Zimbabwe

Bungee jumping (/ˈbʌndʒiː/; also spelled "bungy" jumping, which is the usual spelling in New Zealand and several other countries)^[1][2] is an activity that involves jumping from a tall structure while connected to a large elastic cord. The tall structure is usually a fixed object, such as a building, bridge or crane; but it is also possible to jump from a movable object, such as a hot-air-balloon or helicopter, that has the ability to hover above the ground. The thrill comes from the free-falling and the rebound.^[3] When the person jumps, the cord stretches and the jumper flies upwards again as the cord recoils, and continues to oscillate up and down until all the kinetic energy is dissipated.

History

The first modern bungee jumps were made on 1 April 1979 from the 250-foot (76 m) Clifton Suspension Bridge in Bristol, by David Kirke, Geoff Tabin, and Simon Keeling,^[4][5] all members of the Oxford University Dangerous Sports Club.^[6] The students had come up with the idea after discussing a "vine jumping" ritual carried out by certain natives of Vanuatu.^[5] The jumpers were arrested shortly after, but continued with jumps in the US from the Golden Gate Bridge and the Royal Gorge Bridge (this last jump sponsored by and televised on the American programme That's Incredible), spreading the concept worldwide. By 1982, they were jumping from mobile cranes and hot air balloons.

Organised commercial bungee jumping began with the New Zealander, A J Hackett, who made his first jump from Auckland's Greenhithe Bridge in 1986.^[7] During the following years, Hackett performed a number of jumps from bridges and other structures (including the Eiffel Tower), building public interest in the sport, and opening the world's first permanent commercial bungee site, the Kawarau Bridge Bungy at the Kawarau Gorge Suspension Bridge near Queenstown in the South Island of New Zealand.^[8] Hackett remains one of the largest commercial operators, with concerns in several countries.

Several million successful jumps have taken place since 1980. This safety record is attributable to bungee operators rigorously conforming to standards and guidelines governing jumps, such as double checking calculations and fittings for every jump. As with any sport, injuries can still occur (see below), and there have been fatalities. A relatively common mistake in fatality cases is to use a cord that is too long. The cord should be substantially shorter than the height of the jumping platform to allow it room to stretch. When the cord becomes taut and then is stretched, the tension in the cord progressively increases. Initially the tension is less than the jumper's weight and the jumper continues to accelerate downwards. At some point, the tension equals the jumper's weight and the acceleration is temporarily zero. With further stretching, the jumper has an increasing upward acceleration and at some point has zero vertical velocity before recoiling upward. See also Potential energy for a discussion of the spring constant and the force required to distort bungee cords and other spring-like objects.

The Bloukrans River Bridge was the first bridge to be 'bungee jumped off' in Africa when Face Adrenalin introduced bungee jumping to the African continent in 1990. Bloukrans Bridge Bungy has been operated commercially by Face Adrenalin since 1997, and is the highest commercial bridge bungy in the world.^[9]

In April 2008 a 37-year-old Durban man, Carl Mosca Dionisio, made bungee jumping history when he jumped off a 30 m (100 ft) tower attached to a bungee cord made entirely of 18,500 condoms.^{[10] [11] [12] [13]}

The word "bungee"

The word "bungee" originates from West Country dialect of English language, meaning "Anything thick and squat", as defined by James Jennings in his book "Observations of Some of the Dialects in The West of England" published 1825. Around 1930, the name became used for a rubber eraser. The Oxford English Dictionary records the use in 1938 of the phrase bungy-launching of gliders using an elasticized cord.^[14]

Land diving is a rite of passage for boys of the South Pacific island of Pentecost

Earlier tethered jumping

The land diving (Sa: Gol) of Pentecost Island in Vanuatu is an ancient ritual in which young men jump from tall wooden platforms with vines tied to their ankles as a test of their courage and passage into manhood. Unlike in modern bungee-jumping, land-divers intentionally hit the ground, but the vines absorb sufficient force to make the impact non-lethal.^[15][16] The land-diving ritual on Pentecost has been claimed as an inspiration by AJ Hackett, prompting calls from the islanders' representatives for compensation for what they view as the unauthorised appropriation of their cultural property.^[17]

A similar practice, only with a much slower pace for falling, has been practised as the Danza de los Voladores de Papantla or the 'Papantla flyers' of central Mexico, a tradition dating back to the days of the Aztecs.

A tower 4,000 feet (1,200 m) high with a system to drop a "car" suspended by a cable of "best rubber" was proposed for the Chicago World Fair, 1892-1893. The car, seating two hundred people, would be shoved from a platform on the tower and then bounce to a stop. The designer engineer suggested that for safety the ground below "be covered with eight feet of feather bedding". The proposal was declined by the Fair's organizers.^[18]

Jump from Nevis Highwire Platform in New Zealand

Equipment

Bungee Jump in Normandy, France (Souleuvre Viaduct)

The elastic rope first used in bungee jumping, and still used by many commercial operators, is factory-produced braided shock cord. This special bungee cord consists of many latex strands enclosed in a tough outer cover. The outer cover may be applied when the latex is pre-stressed, so that the cord's resistance to extension is already significant at the cord's natural length. This gives a harder, sharper bounce. The braided cover also provides significant durability benefits. Other operators, including A. J. Hackett and most southern-hemisphere operators, use unbraided cords with exposed latex strands. These give a softer, longer bounce and can be home-produced.

Accidents where participants became detached led many commercial operators to use a body harness, if only as a backup for an ankle attachment. Body harnesses generally derive from climbing equipment rather than parachute equipment.

The highest jump

Looking down from atop the Verzasca Dam bungee tower near Locarno in Ticino, Switzerland

In August 2005, AJ Hackett added a SkyJump to the Macau Tower, making it the world's highest jump at 233 metres (764 ft).^[19] The SkyJump did not qualify as the world's highest bungee as it is not strictly speaking a bungee jump, but instead what is referred to as a 'Decelerator-Descent' jump, using a steel cable and decelerator system, rather than an elastic rope. On 17 December 2006, the Macau Tower started operating a proper bungee jump, which became the "Highest Commercial Bungee Jump In The World" according to the Guinness Book of Records. The Macau Tower Bungy has a "Guide cable" system that limits swing (the jump is very close to the structure of the tower itself) but does not have any effect on the speed of descent, so this still qualifies the jump for the World Record.

Another commercial bungee jump currently in operation is just 13m smaller, at 220 metres (720 ft). This jump, made without guide ropes, is from the top of the Verzasca Dam near Locarno, Switzerland. It appears in the opening scene of the James Bond film GoldenEye. The Bloukrans Bridge Bungy in South Africa and the Verzasca Dam jumps are pure freefall swinging bungee from a single cord.

Guinness only records jumps from fixed objects to guarantee the accuracy of the measurement. John Kockleman however recorded a 2,200-foot (670 m) bungee jump from a hot air balloon in California in 1989. In 1991 Andrew Salisbury jumped from 9,000 feet (2,700 m) from a helicopter over Cancun for a television program and with Reebok sponsorship. The full stretch was recorded at 3,157 feet (962 m). He landed safely under parachute.

One commercial jump higher than all others is at the Royal Gorge Bridge in Colorado. The height of the platform is 321 metres (1,053 ft). However, this jump is rarely available, as part of the Royal Gorge Go Fast Games—first in 2005, then again in 2007. Previous to this the record was held in West Virginia, USA, by New Zealander Chris Allum, who bungee jumped 823 ft (251m) from the New River Gorge Bridge on "Bridge Day" 1992 to set a world's record for the longest bungee jump from a fixed structure.

Bungee jumping from the Souleuvre Viaduct in Normandy

Variations

Catapult

In "Catapult" (Reverse Bungee or Bungee Rocket) the 'jumper' starts on the ground.^[20] The jumper is secured and the cord is stretched, then released and shooting the jumper up into the air. This is often achieved using either a crane or a hoist attached to a (semi-)perma structure. This simplifies the action of stretching the cord and later lowering the participant to the ground.

Trampoline

"Bungy Trampoline" uses, as its name suggests, elements from bungy and trampolining. The participant begins on a trampoline and is fitted into a body harness, which is attached via bungy cords to two high poles on either side of the trampoline. As they begin to jump, the bungy cords are tightened, allowing a higher jump than could normally be made from a trampoline alone.

Running

"Bungee Running" involves no jumping as such. It merely consists of, as the name suggests, running along a track (often inflatable) with a bungee cord attached. One often has a velcro-backed marker that marks how far the runner got before the bungee cord pulled back. This activity can often be found at fairs and carnivals and is often most popular with children.

Ramp

Bungee jumping off a ramp. Two rubber cords - the "bungees" - are tied around the participant's waist to a harness. Those bungee cords are linked to steel cables along which they can slide due to stainless pulleys. The participants bicycle, sled or ski before jumping.

SCAD Diving

SCAD diving (Suspended Catch Air Device) is similar to bungee jumping in that the participant is dropped from a height, but in this variation there is no cord; instead the participant free falls into a net.^[21][22]

Safety and possible injury

Jumping at Kawarau Gorge Suspension Bridge in Queenstown, New Zealand, April 2007.

Bungee jumping injuries may be divided into those that occur after jumping secondary to equipment mishap or tragic accident, and those that occur regardless of safety measures.

In the first instance, injury can happen if the safety harness fails, the cord length is miscalculated,^[23] or the cord is not properly connected to the jump platform. In 1986, Michael Lush died of multiple injuries after bungee jumping for a stunt on a BBC television programme.

Injuries that occur despite safety measures generally relate to the abrupt rise in upper body intravascular pressure during bungee cord recoil. Eyesight damage is the most frequently reported complication.^{[24][25][26][27][28]} Impaired eyesight secondary to retinal haemorrhage may be transient ^[26] or take several weeks to resolve.^[29] In one case, a 26-year-old woman's eyesight was still impaired after 7 months.^[30] Whiplash injuries may occur as the jumper is jolted on the bungee cord and in at least one case, this has led to quadriplegia secondary to a broken neck. Very serious injury can also occur if the jumper's neck or body gets entangled in the cord.^[31] More recently, carotid artery dissection leading to a type of stroke after bungee jumping has also been described.^[32] All of these injuries have occurred in fit and healthy people in their twenties and thirties. Bungee jumping has also been shown to increase stress and decrease immune function.^[33]

In popular culture

In the film GoldenEye, James Bond makes a jump over the edge of a dam in Russia (in reality the dam is in Switzerland: Verzasca Dam, and the jump was genuine, not an animated special effect). The jump in the dam later makes an appearance as a Roadblock task in the 14th season of the reality competition series The Amazing Race.

A fictional proto-bungee jump is a Hawaiian point in the Michael Chabon novel The Amazing Adventures of Kavalier and Clay.

In the film Selena, in which Jennifer Lopez plays Selena Quintanilla-Perez, her character is shown bungee jumping at a carnival. This actual event took place shortly before Selena's murder on March 31, 1995.

In the video game Aero the Acro-Bat, Aero will perform bungee jumping to obtain items like keys to open gates in a level.^[34]

References

External links

• Media related to Bungee jumping at Wikimedia Commons
• The dictionary definition of bungee jumping at Wiktionary