11 June 2018

Sine Wave Motion Q&A

About a year ago, someone on a Facebook-group posted a few questions about the sine wave motion. I stumbled on my reply to these questions and thought that they might be interesting to some readers of my blog. 

Does sine wave and knee spring action describe the same motion? 

Many Korean activities refer to the bending and extending of the knees. Different activities use different terms. For instance the term used in traditional dance might be different from the term used in Taekkyeon, but in practice it is basically the same principle. One such a term is ogeum-jil 오금 질. Ogeum literally refers to the back of the knee and jil means an action; in other words, the bending action of the knee joint. Although I haven’t confirmed this, it is likely that the term “knee spring” which was one of the early terms associated with ITF Taekwon-Do’s sine wave motion may have been a rough translation of ogeum-jil. Another term used in more everyday situations to describe the up-and-down motion accomplished by the bending of the knee gumshil 굼실. This term can for instance be used to describe the oscillating, wave-like locomotion of a worm, and is a term I’ve come across in Taekkyeon to describe their bouncy stepping. Finally, to answer the question, it is my opinion that knee-spring and sine-wave motion is the same thing in as far the sine-wave motion is most often accomplished through knee-spring.

When performing a sine wave, is the movement always “down, up/down”? 

My simple answer is no. Although the most common expression of the sine wave motion is “relax-rise-fall”, this is not the only way it manifests. Take for instance the palm upward block in Gae-Baek Teul where the motion is relax-rise. I personally also do my forearm rising blocks as relax-rise. There are also instances where you may already be in a “raised” position and only dropping is necessary, or you are already in a lowered position and you may only want to rise (imagine doing an upward punch, moving from an L-stance to a vertical stance).

It is useful to think of sine wave motion as the vertical displacement of the body mass. In traditional Korean dance, this is referred to as “verticality”. Sometimes you want do drop your body mass, other times you may want to lift your body mass. It all depends on the technique and purpose.

Is a sine wave performed for every technique execution? 

If you think of the sinewave motion as “relax-rise-fall”, then the answer is no. There are however two principles of what the sinewave motion tries to accomplish in practically every technique; (1) starting from relaxation and (2) accelerating the body mass in the direction of the technique.

An interesting related question is if hip twist is performed in every technique. To this I would answer no, as well. There are for example techniques such as a wedging block or twin punch that does not contain a hip-twist as you can’t rotate your hips in opposite directions at the same time.

Many techniques benefit from both a sine wave motion and a hip-twist, while some techniques can only benefit from one or the other.

What movement causes the initial downward motion? 

Relaxation.

Does a sine wave motion include a knee spring action? 

Yes. See, the answer to the first question.

When did Taekwon-Do introduce the “down, up/down” motion? 

When I look at old footage, I recognize the seeds for “verticality” already from the late 1950s. It seems that it only became formalized in the 1980s, when the initial relaxation became emphasized. This conscious relaxation is, in my mind, the most dramatic evolution to Taekwon-Do movement.

Is hip twist used to help power a technique? 

Yes. Acceleration of the body mass in the direction of the technique is accomplished in two ways: hip twist and rising or dropping the body in the direction of the technique.

To initiate a step, does the student push off with the foot in motion, relax the stationary knee or both? 

It depends on the technique, the initial stance and the next stance. (See a related post: "Motion Without Movement."

Does the 2017 North Korean Demo Team in Muju perform sine wave during Chon-Ji? If so, during which movements? 

Yes. All of them.

29 May 2018

A Personal Anecdote about Siblings Sparring

This post will be somewhat autobiographical and is inspired by a recent discussion on Facebook about siblings sparring against each other at competitions.

Me on the left at about 17 years old, and my brother on the right
at around 24 years old. In the middle, Abrie, one of our friends at the time.

My brother and I started Taekwon-Do together, hence we were at the same rank for most of our early martial arts careers. (He stopped at 3rd degree, but I'm still going.) Although he was older and heavier than me, we still ended up having to compete against each other on several occasions. As colour belts, I personally found it very hard to compete against him in sparring and only won against him one time -- and according to him it is because he let me win. His perspective may very well be true, as the idea of purposefully hurting a member of my family is something that I never could feel comfortable with (and still don't). I'm older and much more experienced now, and have the control and skill to spar against someone without ill-intend. This is something I didn't have when I started TKD.

My parents were not very involved in our Taekwon-Do careers, so in our case, the decision was left to us. Thinking back, I found it traumatic to spar (it felt like fighting, not sparring) against my brother and I think that for me personally it would have been better not to have compete against him in sparring. I didn't have the maturity to be able to differentiate between fighting and friendly competition. My brother on the other hand was far less sensitive than I was as a child, and I don't think it affected him much at all.

It is very likely that my inability to differentiate between friendly sparring and a fight had to do with the history of my brother and I, rather than only my immaturity at the time. My brother is much older than me (7 years) and when we were younger--that is, before we started TKD--he used to bully me. Hence, for me personally it was difficult to differentiate between friendly sparring and fighting when it came to the two of us. I don't think I usually had the same trouble of differentiation when I sparred against other people.

There was only one time that I can remember, around the same time as the picture above was taken, that the sparring turned into a fight. During the competition, right as we started the round, my opponent cursed me because I had beat his friend in a previous bout. I lost my temper and went quite hard; I broke his jaw and he had to be rushed to hospital with a bad concussion. Not one of my proudest moments. Again, this is an example of how, as a teenager, what was simply a sparring match became a "fight" when the other kid made it "personal". Thankfully, I'm not generally a violent person by nature and have seldom had such experiences of losing my temper again. With time and maturity comes calmness.

With this in mind, would it have been better if I did not partake in sparring until I learned to differentiate between sparring and fighting?

Apart from the martial arts which I started as a teenager, I never did other contact sports as a child, nor had I other rough-and-tumble opportunities with my father or older males. I think a child learns to differentiate between "play fighting" and "real fighting" in these contexts and because I missed out on such opportunities I learn those lessons much later in the dojang.

So, no I don't think it would have been better were I not to have been exposed to sparring. I think it served an important function to teach me social concepts like physical contact, hard play, and healthy competition over "fighting". While I do think sparring was good for me, I also think sparring my brother was not good for me (or us).

So, should siblings (children) spar each other at tournaments?

It may be better to speak with the children individually and privately to assess how they feel about it. If they don't have problems with competing against each other, it shouldn't be an issue. However, if it makes one of them feel uncomfortable, I'd suggest that other ways be found, for instance letting them compete in patterns, or in other divisions. Also, if one child already feels inferior to his or her sibling, having the kid lose yet again against the better (often older) sibling is not necessarily a good idea. In fact, parents often think it is good to have their kids participate in the same activities, but that is not always wise. Some children need to find their own unique activities to excel in and not always be in competition for the same thing with their sibling(s). A wise parent knows that their children are different and requires particular parenting.

Literally decades later, and I am still of the opinion that the competition between my brother and I was not a good thing. I believe it affected our relationship negatively in more ways than one.

At the same time, I'm very thankful that my brother and I took up Taekwon-Do together. We are very different people with regards to our characters, worldviews, political opinions, and most other aspects of our personality. The martial arts, however, was something we had in common -- a love we shared.

I'm certain that had we not started it together, I would have been unlikely that I would have enrolled by myself. I was an introvert. Thankfully, my extroverted brother's enthusiasm had me excited enough to try it too. As a colour belt, there were many an evening that I didn't feel like going to training, but my brother encouraged me and set an example for me. I am appreciative of that. Now, about 25 years later, my brother has long since stopped formal martial arts practise, but I'm still hooked. I sometimes wonder how it would be not to do martial arts, but the very idea seems too strange to imagine. Martial arts have become so much a part of me, there is literally not a day that goes by without me thinking about some aspect of it.

13 May 2018

Flexibility and Current Science


A recent academic publication (April 2018) (see the abstract here) provides a meta-analysis of the current literature (23 articles) regarding types of stretching and their effectiveness. The conclusion is that static stretching provides the greatest increase in flexibility (range of motion) compared to other types of stretching. Stretching should be done at least five times per week. (The full article suggests that there is no benefit to stretch every day of the week. Five days per week is enough; six days per week is okay, but seven days per week has no additional benefit. I'm guessing a day or two of rest per week may actually be beneficial, although it is not mentioned.) The stretching duration should be at least five minutes; however, there is no benefit for stretching more than ten minutes. So in short, for the greatest increase in flexibility, use:

  • static stretching 
  • five days per week 
  • for around 8 minutes per muscle group. 
To get the most out of your time, try to do stretches that include several muscles at once. For instance, the regular front split stretches the psoas and quads in the rear leg and the hamstring of the front leg -- and if you flex the front foot and toes back, the calf muscles are stretched too. In this way you can stretch at least four muscles groups by doing just one regular stretch.

By focussing on more than one muscle group, it will still require at least 30 minutes of almost daily devotion to get general, overall flexibility of the lower-body. Therefore, I recommend Netflix-stretching. 😅 I also recommend using PNF-stretching initially to quickly get into a deep stretch, and then staying in the deep stretch for the suggested eight minutes.

Finally, remember, that if you feel any severe pain, sharp or stinging pain or extreme burning sensations, stop the stretch immediately. Also, refrain from hard stretching while injured.

In the video below you can listen to a discussion about stretching in general and also hear about the article mentioned above:



10 April 2018

The Twisting Kick

The twisting kick 비틀어차기 as it is called in ITF Taekwon-Do is, I believe, an iconic kick of Korean martial arts. It is a prominent kick in ITF Taekwon-Do, practised in Kukki Taekwondo (although much less so in WT Taekwondo*), it is a staple kick in Taekkyeon, and can also be found in Tang Soo Do curricula, with variations of it present in Hapkido as well. It is a kick seldom observed in Japanese and Chinese martial arts, although variations of it is sure to be present in some non-Korean martial arts. I have found it an effective technique to use on non-Korean stylists whom are unfamiliar with this deceptive kick.

Twisting Kick at Middle Height
Photo taken by VS Force ©

The term "twisting" is a translation of the Korean biteul-eo 비틀어, based on the verb biteul-da 비틀다, which means to twist or wring something, for instance wringing water out of a wet towel. In the case of the twisting kick, it denotes the outward corkscrew motion of the kick, and also the twisting motion that occurs throughout the body when kicking; often the torso and arms are twisted in the opposite direction of the turning of the hips and vector of the kick. Not only is the kick surprisingly deceptive because of its uncommon out-curved line trajectory, but with correct training it can also be quite powerful because of the way it accelerates. To get power in the kick, one has to strongly rotate the hip outwards, swinging the knee in an arc towards the target, and finally flicking the lower leg out, all in a smooth whip-like snap. The twisting kick is almost always performed with the ball of the foot in ITF Taekwon-Do, as I demonstrate in the photo above.

The video below is a tutorial for how the kick is usually performed in ITF Taekwon-Do.


You can see a WT / Kukki Taekwondo tutorial of their version of the twisting kick here.

For beginners, I teach the twisting kick in steps: First, lift the knee up as if you are going to do a front kick. Next, drop the knee side-ways, so that your lower leg aims towards the horizontal. Finally, flick the lower leg out, into a snap kick. Now attempt to do these steps fluidly, rather than separately. To do the kick at middle and high heights, the knee should be brought diagonally across (rather than straight up), then the hips should be swung outward so that the kick comes out in a nice C-shape arc toward the target.

High Twisting Kick
Image from ITF Encyclopaedia, Vol. 4
In ITF Taekwon-Do one is usually admonished to keep the standing foot flat at the moment of impact because it ensures a more stable base. However, there are certain kicks, such as this one and the spinning reverse turning kick, where the forces involved in the kick put a lot of strain on the knee-joint of the standing leg. Therefore, especially when the target is at a weird angle, I'm a little lax with the flat-foot rule. I let the tensions in my joints and body indicate if it is "safe" to put my heal flat or not. Generally, when I perform this kick at middle or high sections, I do not have my standing foot flat, but rotate on the ball of the foot. Pictures in the ITF Encyclopaedia also show the heel of the standing foot lifted off the floor at the moment of impact.


At lower heights, the twisting kick is quite effective when targeting the lower shin, side of the knee, the inner thigh, and the groin of an opponent positioned in front of you. The side of the knee can be kicked either on the inside or outside and will cause the opponent's leg to buckle. Be careful, as the knee and supporting tendons can be seriously harmed by such an attack, especially when the leg which is being attacked is bearing much weight.

As a middle section kick, it is ideally used when an opponent stands to the side-front of you. Common targets include the floating ribs, bladder, solar plexus (diaphragm), and kidneys. In ITF Taekwon-Do the ball of the foot is the primary attacking tool. When wearing shoes, the toes (tip of the shoe) is an effective weapon. For a middle twisting kick the instep is not an effective attacking tool and not prescribed in ITF Taekwon-Do. However, an often under utilized option is the knee. The twisting knee kick works very well at a middle height for someone standing close to you and towards your oblique.


High Twisting Kick
Photo taken by VS Force ©


High Twisting Kick
Image from ITF Encyclopaedia, Vol. 4
As a high kick, a flexible practitioner may effectively employ this kick against an opponent standing right next to them, kicking their face. The knock-out point on the side of the chin (acupressure point ST-5, known in Korean as daeyeong 대영) is a good target. In the Korean martial art Taekkyeon the high twisting kick is often used for an opponent in front of you. Using the instep as the attacking tool, the kick targets vital spots on the side of the head, such as the chin, the angle of mandible, or temple.

In Taekkyeon, the twisting kick is known as naechagi 내차기, and is usually used to attack either the lower limb or the head. The low kick targets the ankle or lower shin, inner thigh or inside of the knee; while the high kick is aimed at the head. An attack to the head is called a high (nopeun 노픈) naechagi or a gyeotchigi 곁치기. The video below shows a gyeotchigi.


In Hapkido the slap kick (bitgyeo chagi 빗겨 차기) is reminiscent of a twisting kick. The verb bitgyeo-da suggest a skidding quality. Hapkido's slap kick is similar to an ITF vertical kick, but it hits the target in a diagonal skidding motion, unlike the ITF vertical kick that slaps the target with more of penetrative force, rather than skidding. Hapkido's bitgyeo chagi also uses the instep as the attacking tool, like Taekkyeon's gyeotchigi; whereas ITF's vertical kick employs the footsword.  There is another kick in Hapkido that has a very slight twisting quality to it, namely the center-toe kick, also known as front toe kick or spear foot kick. The Korean jokki jireugi 족기 지르기 translates as toe-stabbing kick. The kick is performed like a front kick with the toes pointed (spear foot), however the extended leg twists outward in the hip-socket at the moment of impact. The most common target is the side of the groin or other sensitive areas and pressure points. I'm not sure if Hapkido's front toe kick really qualifies as a "twisting" kick as the general vector of the kick is not performed in a C-shape arc.

As for the twisting kick in non-Korean martial arts, I have not yet been convinced that it is the same kick. I've been pointed to the uchi mawashi geri and gyaku mawashi geri in the Karate styles. I've looked at several examples of these kicks on YouTube and what I've seen are simply not twisting kicks as I understand it; instead, they are what we in ITF Taekwon-Do may call hooking kick and outward vertical kick, or fan kick (buchae chagi 부채 차기). After more personal research I found a kick in Kyokushin Karate called uchi heisoku geri, which I think may very well be considered a twisting kick. I wonder if the fact that the founder of Kyokushin Karate was a Korean, may be the reason this kick is part of their curriculum. I've been told that there is an equivalent kick in some Chinese martial arts as well as in the Brazilian martial art Capoeira; however, I have not been pointed to specific examples to be able to confirm this.

The twisting kick is one of my favourite kicks. It is a relative short range kick, and is therefore useful in the punching range and because of its unconventional vector, it is quite difficult to notice and defend against. Before practising the twisting kick, I strongly recommend warming up your knees and stretching your groin and hip flexor muscles. Another tip for the kick is to keep your leg relaxed and perform the kick in a whip-like action as this will increase the speed and power of the kick.

...ooOoo...

* While the twisting kick is part of traditional Taekwon-Do curricula, and can therefore be found in some Kukki Taekwondo schools, I think it is seldom practiced in WT Taekwondo schools. It has been my experience that most WT Taekwondo practitioners I have spoken to, don't practice it, and surprisingly, many people don't know about it. I think the reason for this is that the twisting kick was not powerful enough to score a point in full-contact WT Taekwondo competitions, in part because it is often taught with the instep rather than the ball of the foot, in Kukki/WT schools. However, with the new WT rules that allow for points scored to the head with light contact kicks, it is foreseeable that the twisting kick may make a comeback.

14 March 2018

South Africa Trip 2018

My annual trip to South Africa in January and February this year was quite a blessed one. Apart from spending some quality time with family and friends, I also had the opportunity to visit several martial art schools and friends.

In Cape Town, I visited the Instructor Jaren Philips' ITF Taekwon-Do school in Green Point, where I shared some thoughts on Korean body culture and the overlap between Taekkyeon and ITF Taekwon-Do.

With black belts at the Green Point Dojang.
In Kwa-Zulu Natal I visited my friends at the Pinetown Stingers Dojang where we practiced some of break-falling and joint-manipulation techniques.

With some members of the Pinetown Stingers Club. 

In Centurion I presented an ITF principles seminar with participants attending from the greater Pretoria region, Potchefstroom, and the Vaal Triangle. The workshop centered on re-thinking how we apply fundamental motions in a practical manner that makes full use of different possibilities presented to us within the context of the Theory of Power.

WIth some participants at the workshop in Centurion.
I was delighted to be able to visit the Potcheftroom Taekwon-Do school this year. I started this dojang exactly 20 years ago and couldn't have imagined that it would continue to exist for such a long time. The school have always been relatively small, but the quality is consistent and under instructor Philip's care, I am happy say that the Potchefstroom Dojang is doing very well.

With some students at the Potchefstroom Taekwon-Do Club.

Apart from my Taekwon-Do adventures, I also gave an introductory Hapkido seminar in Cape Town. There are hopes that from a small Hapkido training group a Hapkido school will open in the Mother City.

With Anthony Lapperts
I also introduced, for the first time in South Africa, hopaesul -- the study of a Korean weapon known as hopae. The introduction was presented to some higher level black belts as an addendum to the Centurion workshop.

With the Korean weapon, hopae