Action sports, adventure sports or extreme sports are activities perceived as involving a high degree of risk. These activities often involve speed, height, a high level of physical exertion and highly specialized gear. Extreme tourism overlaps with extreme sport. The two share the same main attraction, "adrenaline rush" caused by an element of risk, and differ mostly in the degree of engagement and professionalism.
The definition of extreme sports is not exact and the origin of the terms is unclear, but it gained popularity in the 1990s when it was picked up by marketing companies to promote the X Games and when the Extreme Sports Channel and Extreme International launched. More recently, the commonly used definition from research is "a competitive (comparison or self-evaluative) activity within which the participant is subjected to natural or unusual physical and mental challenges such as speed, height, depth or natural forces and where fast and accurate cognitive perceptual processing may be required for a successful outcome" by Dr. Rhonda Cohen (2012).
While the use of the term "extreme sport" has spread everywhere to describe a multitude of different activities, exactly which sports are considered 'extreme' is debatable. There are, however, several characteristics common to most extreme sports. While they are not the exclusive domain of youth, extreme sports tend to have a younger-than-average target demographic. Extreme sports are also rarely sanctioned by schools for their physical education curriculum. Extreme sports tend to be more solitary than many of the popular traditional sports (rafting and paintballing are notable exceptions, as they are done in teams).
Activities categorized by media as extreme sports differ from traditional sports due to the higher number of inherently uncontrollable variables. These environmental variables are frequently weather and terrain related, including wind, snow, water and mountains. Because these natural phenomena cannot be controlled, they inevitably affect the outcome of the given activity or event.