#MYTH BUSTING 
Why 'sine waves' used be various TKD organizations are scientifically baseless and unnatural  
Movements not used by any of the 'real combat arts'. The power of striking comes from the Hip twist or the projection of the shoulders (as in boxing) and the natural  movement of the shoulders and hips in the process of executing an explosive power technique.
The above principals are incorporated in Yun Jung Do remembering that Grandmaster Yun was the chairman of Technique of ITF
Tae Kwon  Do  world wide and one of the original masters under General Choi (founder of ITF TKD) before he resigned in 1987 after
22 years in ITF.
Grandmaster Yun never was an advocate of "sine waves" but today 2020 we find the above organizations have made a "theory" about  "patterns or Tuls". 
These 'unscientific' theory's were left behind by Yun Jung Do in 1989 as we moved forward on a the basis of natural human movement based on the execution of explosive power "Skills and Drills".
Everybody is entitled to advocate whatever "theory" however, proving the "theory" is a totally different matter .
Yun Jung Do has removed "unnatural movements " out of our syllabus, in fact as we evolved out of ITF Tae kwon do Grandmaster Yun re-created the YJD Patters or Tuls in a simplified form taking out any of the non-sensical movements that he used to teach in
ITF Tae Kwon Do .
The reason he did this, is not only was he the former chairman of technique of ITF TKD, he was there when General Choi actually designed the original ITF patterns and much of the movements were designed to "fit" the Korean philosophy of General Choi (actual historical calligraphy)  more then be of any practical self-defenses applications  within the pattern itself .
Under the direction of General Choi Grandmaster Yun and Grandmaster Park Jung Tae had to follow another pattern designed in honor of the North Korean president ? while this is, I suppose , philosophically interesting , it had little to do with a direct self defense applications , rather then the practitioner actually tracing out the Korean calligraphy (written by General Choi) in the form of a human martial arts pattern of tul.
This is why Grandmaster Yun created Yun Jung Do as he was 'sick and tired' of teaching what he knew on many fronts was simply 'philosophical' forms or patterns-Tuls.
So in Yung Jung Do the focus is not on patterns as such but the 'component skills and drills' that must be trained thousands of times in practical self-defense combinations .
Anybody who has  trained under Grandmaster Yun knew his speed and strike power was exceptional , this is why I resigned from ITF and followed GM Yun , I wanted to follow a genuine authentic Grandmaster who could deliver and practice what he preached . I was not interested in Korean politics , however interesting that was historically.

Today 2020-21 YOU have a choice to join the NEW GENERATION OF 
HEALYS INTEGRATED COMBAT SOLUTIONS  

spearheaded by Grandmaster Yun and senior Instructor Graham Healy . 
Or as Albert Einstein said repeating the same 'historical' thing over and over again and expecting a different result
is the definition of Insanity. 
My personal point of view is this "anything I teach I can apply in the real world" in real self-defense situations and have done on many occasions , I do not what to waste my time on miscellaneous non effective patterns,  but prefer to focus on the SKILLS & DRILLS and EXPLOSIVE POWER Techniques and that's exactly what we do in Yun Jung Do -Healy's  Integrated Self-defense academy.
Plus we are FOCUSING on Personal Development of the Individual in Mind , Body and Spirit 
Which is UNIVERSAL APPLYING TO ALL PEOPLE and ALL NATIONS GLOBALLY 
We are building the 
NEXT GENERATION 
HEALYS INTEGRATED COMBAT SOLUTIONS 
why don't you Join Us ?
Graham Healy