The Parkour, l'art du déplacement

Parkour
Parkour (sometimes abbreviated to PK) or l'art du déplacement (English: the art of movement) is an activity with the aim of moving from one point to another as efficiently and quickly as possible, using principally the abilities of the human body. It is meant to help one overcome obstacles, which can be anything in the surrounding environment—from branches and rocks to rails and concrete walls—and can be practiced in both rural and urban areas. Parkour practitioners are referred to as traceurs, or traceuses for females.
Founded by David Belle in France, parkour focuses on practicing efficient movements to develop one's body and mind to be able to overcome obstacles in an emergency.

Overview
Parkour is a physical activity that is difficult to categorize. Often miscategorized as a sport or an extreme sport, parkour has no set of rules, team work, formal hierarchy, or competitiveness. It is an art or discipline that resembles self-defense in the ancient martial arts. According to David Belle, "the physical aspect of parkour is getting over all the obstacles in your path as you would in an emergency. You want to move in such a way, with any movement, as to help you gain the most ground on someone or something, whether escaping from it or chasing toward it." Thus, when faced with a hostile confrontation with a person, one will be able to speak, fight, or flee. As martial arts are a form of training for the fight, parkour is a form of training for the flight. Because of its unique nature, it is often said that parkour is in its own category.
A characteristic of parkour is efficiency. Practitioners move not only as fast as they can, but also in the most direct and efficient way possible; a characteristic that distinguishes it from the similar practice of free running, which places more emphasis on freedom of movement, such as acrobatics.Efficiency also involves avoiding injuries, short and long-term, part of why parkour's unofficial motto is être et durer (to be and to last). Those who are skilled at this activity normally have an extremely keen spatial awareness (a.k.a. air sense).[citation needed]
Traceurs say that parkour also influences one's thought process by enhancing self-confidence and critical-thinking skills that allow one to overcome everyday physical and mental obstacles. A study by Neuropsychiatrie de l'Enfance et de l'Adolescence in France reflects that traceurs seek for more sensation and leadership than gymnastic practitioners.

Terminology
The first terms used to describe this form of training were l'art du déplacement and le parcours.
The term parkour IPA: [paʁˈkuʁ] was defined by David Belle and his friend Hubert Koundé. It derives from parcours du combattant, the classic obstacle course method of military training proposed by Georges Hébert.
Traceur [tʁasœʁ] and traceuse [tʁasøz] are substantives derived from the French verb tracer which normally means "to trace",or "to draw", but also translates as "to go fast".

Movements
There are fewer predefined movements in parkour than gymnastics, as it does not have a list of appropriate "moves". Each obstacle a traceur faces presents a unique challenge on how they can overcome it effectively, which depends on their body type, speed and angle of approach, the physical make-up of the obstacle, etc. Parkour is about training the bodymind to react to those obstacles appropriately with a technique that works. Often that technique cannot and need not be classified and given a name. In many cases effective parkour techniques depend on fast redistribution of body weight and the use of momentum to perform seemingly impossible or difficult body manoeuvres at speed. Absorption and redistribution of energy is also an important factor, such as body rolls when landing which reduce impact forces on the legs and spine, allowing a traceur to jump from greater heights than those often considered sensible in other forms of acrobatics and gymnastics.
According to David Belle, you want to move in such a way that will help you gain the most ground as if escaping or chasing something. Also, wherever you go, you must be able to get back, if you go from A to B, you need to be able to get back from B to A, but not necessarily with the same movements or passements.
Despite this, there are many basic techniques that are emphasized to beginners for their versatility and effectiveness. Most important are good jumping and landing techniques. The roll, used to limit impact after a drop and to carry one's momentum onward, is often stressed as the most important technique to learn. Many traceurs develop joint problems from too many large drops and rolling incorrectly. Parkour has sometimes received concerns for its health issues due to large drops. Communities in Great Britain have been warned by law enforcement or fire and rescue of the risk in jumping in the high buildings. Although David Belle has never been seriously injured while practising parkour, there is no careful study about the health issues of large drops and traceurs stress gradual progression to avoid any problems. Despite this, the American traceur Mark Toorock and Lanier Johnson, executive director of the American Sports Medicine Institute say that injuries are rare because parkour is based on the control of movements not on what cannot be controlled.