Bungee Jumping

History
The word "bungee" (pronounced /ˈbʌndʒiː/) originates from West Country dialect, 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 word bungy, as used by A J Hackett, is "Kiwi slang for an Elastic Strap". Cloth-covered rubber cords with hooks on the ends have been available for decades under the generic name bungy cords.
In the 1950s David Attenborough and a BBC film crew brought back footage of the "land divers" (known as "Naghol") of Pentecost Island in Vanuatu, young men who jumped from tall wooden platforms with vines tied to their ankles as a test of their courage and passage into manhood. 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.

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, Chris Baker, Simon Keeling, Tim Hunt and Alan Weston of the Oxford University Dangerous Sports Club. The jumpers were arrested shortly after, but continued with jumps in the US from the Golden Gate and Royal Gorge bridges, (this last jump sponsored by and televised on the American program That's Incredible) spreading the concept worldwide. By 1982 they were jumping from mobile cranes and hot air balloons.
Commercial bungee jumping began with the New Zealander, A J Hackett, who made his first jump from Auckland's Greenhithe Bridge in 1986. 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 Queenstown in the South Island of New Zealand. Hackett remains one of the largest commercial operators, with concerns in several countries.
Despite the inherent danger of jumping from a great height, several million successful jumps have taken place since 1980. This 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 reaches its natural length the jumper either starts to slow down or keeps accelerating depending upon the speed of descent. One may not even start to slow until the cord has been stretched a significant amount, because the cord's resistance to distortion is zero at the natural length, and increases only gradually after, taking some time to even equal the jumper's weight. See also Potential energy for a discussion of the spring constant and the force required to distort bungee cords and other spring-like objects.

Equipments
The elastic rope first used in bungee jumping, and still used by many commercial operators, is factory-produced braided shock cord. This 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 in which the latex strands are exposed (pictured at right). These give a softer, longer bounce and can be home-produced.
Although there is a certain elegance in using only a simple ankle attachment, accidents in which participants became detached led many commercial operators to use a body harness, if only as a backup for an ankle attachment. Body harnesses are generally derived from climbing equipment rather than parachute equipment.


Highest Jump
In August 2005, AJ Hackett added a SkyJump to the Macau Tower, making it the world's highest jump at 233 metres (764 ft). 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 does have a "Guide cable" system which 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.
There is another commercial bungee jump currently in operation which is just 13m smaller, at 220 metres (720 ft). This jump, which is made without guide ropes, is located near Locarno, Switzerland and takes place from the top of the Verzasca Dam. This jump was prominently featured in the opening scene of the James Bond film GoldenEye.
The Bloukrans Bridge in South Africa and the Verzasca Dam jumps are pure freefall swinging bungee from a single cord.
Bloukrans Bridge was opened in 1997 and uses a pendulum bungee system. It is 216m high, from the platform to the river below.
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.

Variations

Catapult

In "Catapult" (Reverse Bungee or Bungee Rocket) the 'jumper' starts on the ground. The jumper is secured and the cord 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.
"Twin Tower" is similar with two oblique cords.

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 which is used to mark 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 participants waist to a harness. Those bungee cords are linked to steel cables along which they can slide due to stainless pulleys. The participants ride bike, sled or ski before jumping.

Safety And Injuries
Injuries occurring as a result of bungee jumping may be divided into those which may occur secondary to equipment mishap or tragic accident and those which may occur regardless of any safety measures. In the first instance, one can be injured during a jump if the safety harness fails, the cord elasticity is miscalculated, or the cord is not properly connected to the jump platform. In 1986 Michael Lush died of multplie injuries after bungee jumping for a stunt on a BBC television programme and in 1997, Laura Patterson, one of a 16-member professional bungee jumping team, died of massive cranial trauma when she jumped from the top level of the Louisiana Superdome and collided head-first into the concrete-based playing field. She was practising for an exhibition intended to be performed during the halftime show of Super Bowl XXXI Injuries which may occur despite equipment being made safe are generally related to the abrupt rise in upper body intravascular pressure during recoil of the bungee cord. Damage to eyesight has been the most frequently reported complication with respect to this. Impaired eyesight secondary to retinal haemorrhage may be transient or take several weeks to resolve In one case, a 26 year old woman's eyesight was still impaired after 7 months 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. More recently, carotid artey dissection leading to a type of stroke after bungee jumping has also been described. All of these injuries have occurred in fit and healthy people in their twenties and thirties.