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The crowd holds its breath as a helmet-clad skateboarder flies off an 8-foot ledge and lands on a 2-inch metal handrail.  He skids along the handrail, bypassing three flights of stairs, and leaps over a row of hedges nearly as tall as himself.  At the end of the strenuous course, the skateboarder pauses for a moment to reflect on his run.  Sure, he'd wowed the crowd, but was it enough for a win.  Had he skated fast enough and jumped high enough?  Should he have taken more risks?

Gone are the days when skateboarding was a simple glide down a flat sidewalk and the only obstacle was getting past the neighbor's dog. Today's skateboarders stretch physics to the limit and thrive on the thrill of risk taking. While some would question their sanity, participating in seemingly dangerous sports is a growing trend.

Extreme sports and those who seek risks were the focus of a Sept. 6, 1999, Time magazine cover story.  The article suggested that Generations X and Y have fewer real risks to face and; therefore, some feel the need to live out challenges through risky behavior.  While previous generations were burdened with global wars and the threat of world destruction, recent generations have lived through a relatively peaceful era.

For whatever reason, extreme sports are getting more attention that ever.   In 1995 ESPN jumped on the bandwagon with the first Extreme Games, now known as simply "X Games."  The televised event is broken into two annual bouts: the Winter X Games and the Summer X Games.  Both seasons have specific sports, just like the Olympics.  Only, these sports would never fly at the Olympics.  Some of the events include aggressive in-line skating, bicycle stunt riding, snowboarding, skysurfing, street luge, ice climbing and, of course, skateboarding.

Skateboarding Tricks
Although skateboards have been around for at least half a century, the style of skateboarding has evolved.  In the early 1970s, the complexity of skateboarding escalated with the invention of a new type of wheel that allowed for more traction, speed and smoothness.  As skateboarders began executing a wider range of maneuvers and tricks, insurance companies were forced to raise rates and many skateparks had to close.  Skateboarders were forced onto the streets to practice and had to build their own plywood ramps. Thus, street skating was born.

Among the tricks developed during this era is one that has become a skateboarding fundamental and the basis for other, more complicated maneuvers.  The "ollie" was invented in the late 1970s by Alan "Ollie" Gelfand.  Simply put, the ollie is a jumping technique that allows skaters to hop over obstacles.  While in midair, the board appears to stick to the skater's feet.   Many people assume that the skater's shoes are somehow attached to the board.  They're not.  It's just a matter of science.

"Ollie Science"
Three forces act on a skater while performing an ollie: The skater's weight, the force of gravity on the board, and the force of the ground pushing up on the skateboard.  These three forces balance out to zero, which means the skater rolls along at a constant speed unless another force is added.

To add the fourth force, the skater crouches down, creating a low center of gravity and then accelerates upward by quickly straightening his legs and throwing his arms in the air.  It is important that the rear foot exerts a much greater force on the tail of the skateboard than the front foot exerts on the nose.  As the tail of the board slams into the ground, the ground responds with a force that causes the board to bounce upward.

When the board is in the air, the skater slides his front foot forward.  The friction between the bottom of the skater's shoe and the rough surface of the board drags the board upward even higher.  Next, the front foot of the board is pushed down, which causes the back of the board to rise.  At this point, the skateboard appears to be stuck to the rider's feet.  As the force of gravity takes over, the skater and board begin to descend, and the skater bends his knees to cushion the impact of the ground.

Classroom Discussion...
1.  Why is it necessary for the skater to crouch before jumping?
2. A type of sandpaper called grip tape often is affixed to the top of skateboards.  What affect would grip tape have on an ollie?

Street Luge
If hanging in midair with only a skateboard for comfort sounds risky, imagine traveling 65 miles per hour downhill.  Still not dangerous enough?  What about lying down on a skateboard-like contraption with no brakes?

That is the premise of street luge.  Like most extreme sports, street luge evolved from existing popular sports.  It is a combination of ice luge and skateboarding.  The luges are aluminum frames with steel seats where the rider reclines on his back.  Four large urethane wheels provide the road traction.  Steering is done by shifting body weight from side to side.

The racecourse normally is lined with bales of hay and drops hundreds of feet in 6/10 of a mile.  That's pretty steep.  For safety, the riders wear full-body leather suits, treadless shoes, motorcycle-like helmets, and ultra-padded deerskin gloves.  The gloves are padded with two layers of deerskin, one layer of kevlar and one layer of plastic.  The special helmets are fitted with serious neck support, and knee and elbow pads are always worn.  Although extreme sports are risky by nature, most extreme athletes take safety seriously.

Snowboarding
Snowboarding is a combination and modification of existing popular sports.  Snowboarding can be compared visually to skateboarding or surfing, only it's done on snow.  The rider stands on the board with one foot forward and facing one side of the board.  The feet are attached to the board via high-back or plate bindings.  The object is to make it from the top of a mountain to the bottom using only the snowboard.

Mountain Biking
Some extreme sports buck the flat surfaces of pre-designed racecourses and opt for a more natural terrain. In mountain biking, the rider has to be constantly aware of the obstacles ahead. When speeding downhill in a natural setting, the rider's balance is extremely vulnerable to any stone or branch that meets the tires of the bike.

Most mountain bikes have wide tires, while road bikes have thin tires.  Thin tires are better for smooth surfaces because there is less contact with the road, which means less friction. But on dirt trails, thin tires tend to sink into the dirt.  Tires on most mountain bikes are made of natural rubber and have rough treads.  This allows the tire to grip the dirt trail better and float over the rough surfaces.

Aerodynamics plays a huge role in bicycling speed.  Wind resistance provides the greatest obstacle for bicyclists.  The easiest way to overcome wind resistance is to become more streamlined.  That's why bike racers usually keep their heads bent close to the handlebars.

In road racing, bicyclists often travel in lines to improve performance, as do birds.  This is known as drafting.  As the bicycle moves, a low-pressure area is created directly behind the rider.  If a second rider moves into the area, the low pressure helps move the bicycle forward.  Surprisingly, the lead bicyclist's performance also improves when someone fills in the low-pressure area.   However, the lead bicyclist must still expend more energy.  The shorter the distance between the two bikes, the more effective is the drafting.

Beyond Extreme
Several sports go beyond what some call extreme.   Jumping from an aircraft at 10,000 or more feet puts skydiving in a different category.  Some might call it ultra extreme.  Others call it just plain crazy.

After jumping from an airplane, skydivers accelerate to around 120 miles in just a few seconds.  The free fall lasts about 40 to 60 seconds and the parachute deploys at an altitude of approximately 5000 feet.  Once the parachute opens there is a calm 4- to 10-minute ride to the ground.

BASE-Jumping
BASE-jumping is a relatively new sport.  Yet, it has a relatively high fatality rate.  BASE is an acronym for building, antenna, span (bridge) and earth (cliffs).   Jumpers leap from stationery objects and deploy a parachute.  Unlike skydiving, no aircraft is involved.

In its 18-year history, BASE-jumping has taken the lives of nearly 50 people.  In October 1999, a 60-year old parachutist plunged to her death when her parachute failed to open.  Ironically, the woman was jumping in protest of rules banning BASE-jumping off El Capitan in Yosemite National Park.  The jump-gone-wrong was a sad reminder that extreme sports sometimes can become too extreme.

Although extreme sports can be a rush for some, safety precautions should not be avoided merely to make the sport more dangerous.  Anyone who chooses to participate in an extreme sport should first consult a professional to determine what pre-training and proper equipment are needed for the sport.

Classroom Discussion...
1. Other than sports, what other types of risky behavior do you observe in society today?
2.  To what do you attribute the rise in popularity of extreme sports?
3.  What risk management steps could be taken to make an extreme sport safer?

Sources
Greenfeld, Karl Taro. "Life on the Edge." Time. 6 Sept. 1999.
Harris, Ron. "X Games' Street Luge Takes Speed and Spills to the Hills of San Francisco.”  Associated Press.  25 June 1998.
Koeppel, Don.  Extreme Sports Almanac.  Lowell House. 1998.
Tomlinson, Joe. Ultimate Encyclopedia of Extreme Sports.  Carlton Books. 1999.
"Frontside Forces and Fakie Flight: The Physics of Skateboarding Tricks." The Exploratorium. 1999. http://www.exploratorium.edu/skateboarding/trick.html
"Skateboarding" and "Skydiving" and "Mountain Biking." Comcast Online.  1999.
Wilson, Chris. "Skydive." http://www.cyberparent.com/sports/skydive.htm CyberSports. 1998.
"X Games." http://www.expn.com  ESPN.com. 1999.
"What is Snowboarding?"  DWL.  1999.

Risk vs. Reward | Split-Second Choices
Creative Decisions | Event Planning | Extreme Sports

Last Updated: 02/16/03
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