This information is really for advanced or existing taekwondo students.
Taekwondo was founded in 1955. Back in 1983, the original NLTKD was a founder member of the new TAGB, and we cut our political ties to General Choi Hong Hi . We stuck with the traditional style of patterns as the Sine Wave style that Gen Choi apparently began to advocate was unknown to us at the time.
According to the well rated book “A Killing Art: The Untold History of Tae Kwon Do” by Alex Gillis, the Sine Wave was a “gift” to the North Korean’s (citation) from General Choi Hong Hi and to distinguish Taekwondo from its Karate origins AND traditional Taekwondo. So basically the “Sine Wave” style was created for political reasons. For more info on General Choi Hong Hi see wiki.
Ask anyone to punch as hard as possible and he or she will naturally twist their hips and shoulders. It is a natural movement hard coded into our DNA. The “hip twist” technique has been used for centuries in most fighting and martial arts styles. The NLTKD practices it too.
In competition sparring, example Taekwondo, kick boxing, regular boxing or MMA, everyone uses “hip twist” to generate power and speed. Sine Wave is non-existent anywhere in the real world.
Now bear in mind, no one ever joins a martial arts club to learn patterns, so adding a bobbing up and down movement called “Sine Wave” to patterns lessons seems pointless. People join a martial arts club for fitness, self defence, sparring and/or confidence. The sine wave style does nothing to help achieve these goals.
So that is why the NLTKD does not teach Sine Wave style. We teach the original Traditional style Taekwondo as in the video below and still practiced in many taekwondo schools worldwide.