Choi Hong Hi
The emphasis on speed and agility is a defining characteristic of Taekwondo and has its origins in analyses undertaken by Choi Hong Hi. The results of that analysis are known by ITF practitioners as Choi's "Theory of Power". Choi based his understanding of power on biomechanics and Newtonian physics as well as Chinese martial arts. For example, Choi observed that the kinetic energy of a strike increases quadratically with the speed of the strike, but increases only linearly with the mass of the striking object. In other words, speed is more important than size in terms of generating power. This principle was incorporated into the early design of Taekwondo and is still used.