Parkour is a physical discipline created by David Belle that uses movement to overcome obstacles in a person's environment. It aims to strengthen both the mind and body. Belle was influenced by Georges Hebert's theory of focusing on one's own abilities without technology. Parkour traces a person's movement based on Newton's Second Law relating force, mass and acceleration. It has grown in popularity globally through media exposure and influenced action movies and video games. Military and law enforcement now use parkour techniques in training programs.