Extreme sports are activities with a high level of danger based on speed, height, physical exertion, and chance of serious injury or death. All extreme sports are risky, hence the name extreme, and leave athletes "amped," or overcome by an adrenaline rush. Although that is most likely the appeal of it, certain activities pose more danger than the rest.
River Surfing
Surfing in an ocean is dangerous if you take into account the animals that could be lurking for food and the fierceness of waves that can crash down upon your tiny body, as in the recent big wave surfing. However, a new branch of surfing has taken over South America and is slowly creeping into the United States.
In river surfing, popular along the Amazon, the surfer rides a tidal bore, water that has come in from rising tidal waves, and attempts to go for miles. Now, instead of sharks, you have the alligators to contend with, and aside from the simple fear of drowning as the water sucks you under, you must dodge rocks and tree branches along the way.
Cliff Diving
Olympic pool diving is a sport with difficult techniques that must be practiced. Although the beauty (and high score) of that perfect dive is something all divers hope for, there is little risk. I suppose there is a chance in you-know-where of diving too low and hitting the bottom, but it is not likely. There have been instances of a diver smacking his head off the platform, ala Greg Louganis in the 1988 Olympics in Seoul, Korea. But again, the odds are slim.
Those fear-seekers who want to up the ante of traditional diving can try cliff diving. In much the same goal of a beautiful jump, divers leap from a cliff edge into the pool of water below. Cliff diving can reach heights of 28 meters, roughly 91 feet. When falling so far, acceleration increases and divers must have a tight vertical form upon entering the water so to avoid bodily contortion, similar to that sustained after jumping off a building onto the cement. As if that weren't enough to worry about, divers must also be aware of shallow areas and jagged rocks, since the visibility is not clear like in a swimming pool.
Sledging
Take a canoe, cut off the back half, lay stomach-down inside, slide into the water donning a wetsuit, helmet, and flippers, and race down the rapids. There you have it - sledging. This cross between white water rafting and boogie-boarding was invented in Europe and popularized in New Zealand. It has the same hazards as rafting - rocks and, of course, drowning - but sledging is actually more dangerous. Your limbs will be flailing around, smacking off of every river obstacle you pass, and rather than a paddle to guide your direction, muscles will be stressed to their limits as your body fights its way through the current.
Sky Diving/BASE jumping
People were not born with wings, but that sure hasn't stopped them from soaring through the air. Jumping out of a plane was once reserved for trained military professionals, but is now an adventure for anyone 18 years of age or older willing to free fall for the ten minutes or so it takes to descend two miles from the clouds to the earth. Parachute mishaps are not the norm, but the chance always exists for a malfunction, leading your body to accelerate and spin uncontrollably until stopped only by the ground.
BASE jumping, and acronym for Building, Antenna, Span, and Earth, is a branch of sky diving. The concept is the same, only this sport entails scaling a building or some other large stationary object and hurdling off in hopes that your parachute will slow you down before reaching the concrete.
T.S. Eliot said, "Only those who will risk going too far can possibly find out how far one can go." There is no limit to the imagination of extreme sports. Despite the risks, people continue to test themselves and break free from their comfort zones as they attempt the unimaginable.