The Physics of Rebounding for Super Speed

from blackbeltmag.com - https://blackbeltmag.com/physics-and-kenpo/wrap-up

(part 1)

Every session in the dojo should be another step towards our ultimate goal, which is why we must take our training seriously. However, we also need to be able to appreciate moments of levity. That’s why I’d like to start today’s discussion with a quote from Master Ken regarding fighting a Kenpoist.

“In Kenpo, students are actually encouraged to hit themselves during a fight. Which means if you fight a Kenpo black belt long enough, eventually he’ll kick his own a**.”

This is, of course, a joke about the rebounding slap seen performed by Kenpoists all over the world. If you are a Kenpo practitioner, you are most likely aware of the reason behind this action of rebounding and its potential applications. If your art doesn’t employ this concept, then it may appear funny and foolish. To an outsider it can look like a guy slapping himself for no apparent reason, which may be true in some cases. However, a skilled and self-aware Kenpoist is conscious of their actions and uses rebounding to harnesses and immediately rerelease power.

“Harness and immediately rerelease power.” What does this mean?

Let’s take a moment to consider a baseball and what happens to it from pitch to a homerun hit. A pitcher throws a baseball at roughly 90mph. The batter swings his bat to strike the ball with a barrel speed of his bat around 80mph. There’s a loud cracking sound as the bat smacks the ball and, nearly instantaneously, the ball is sent off in a direction nearly opposite of its original path at over 100mph. Both the bat and the ball act upon one another. The heavier and continuously powered bat absorbs the energy of the ball and continues on its path. A homerun ball results from the bat’s massive force acting on the baseball creating huge acceleration of the ball opposite its original path when it left the pitcher’s hand.

Now that we have a visual example in mind, let’s get into the science of this action. A force from the bat is acting upon the ball to change its direction. The physics equations for what is happening in this example are as follows:

F=ma

Force = mass x acceleration

Force is equal to the mass of an object multiplied by the acceleration of that same object.

To deeper understand the resulting change of direction of the ball we must define “acceleration.” That is where the following equation comes into play.

a = (vf–vi)/Δt

Acceleration is equal to the change in velocity (resulting velocity – initial velocity) of an object divided by the amount of time it takes for that change to happen. We plug these pieces of the “Acceleration equation” into the original “Force” equation (F=ma) for “a” and end up with the following representation of the force exercised on the ball while it is in contact with the bat.

F = (mvf–mvi)/Δt

Here we are shown that the FORCE exerted on the ball by the bat is equal to the mass of the ball (m) multiplied by the final velocity (vf) of the ball minus the mass of the ball times the initial speed of the ball (vi). Pay special attention to how the positive and negative of the velocity affects the outcome. Because they are moving in opposite directions the initial velocity is considered a negative because it’s going in the opposite direction of where it ends up heading. The net result of the subtraction in the equation is that it is added to the first part of the equation. The (mvf-mvi) is then divided by the amount of time (Δt) the bat is in contact with the ball for our final understanding of the force used to create that change in speed and direction.

As we wrap our mind around these equations and how they relate to speed and acceleration, the overall take-home message I want to impart is the following:

The greater the change in directional speed of an object and the shorter the time frame in which the change of speed happens the greater the observed force must be.

The exact numbers for the speeds of the bat and ball are not the important part here. What is important is the overall concept. The speed at which the ball leaves the bat is enhanced and is greater than the speed of either object’s original movement. Imagine for a moment that the batter no longer had a bat. Instead, he was forced to catch the ball barehanded and, with the same hand, throw it back as fast as he could. He would have to decelerate the pitched ball’s speed by absorbing the moving ball’s force with his musculature and then reaccelerate it to throw it towards the outfield wall. It’s safe to say that it would take longer to get the ball moving towards the outfield and would also leave his hand with less velocity than in the previous example where it was hammered off the bat.

You may be wondering how this baseball analogy applies to Martial Arts. The idea of this parallel to baseball is to have us look at our torso compared to the bat and our hands to the baseball. After a hand strike is thrown, it returns to us. We don’t simply leave it out there for an attacker to grab or manipulate. So, as it returns toward the bulk of our body, we must instantaneously decide if it is to be deployed again or will it stay back in a fighting or checking position. If we’re deploying it once more, we can reduce the time out of battery and increase its velocity back into the fight by rebounding the hand off our torso. Like in the baseball example, the projectile bounces off the heavier object and it forced back towards whence it came.

In Part 2, we will delve further into the practical application, the lab of the dojo if you will, and increase our understanding of the rebounding principle.

Salute,

Ian Lauer

B.A. Chemistry

from blackbeltmag.com - https://blackbeltmag.com/rebounding-for-speed-part-2

(part 2)

In Part 1 of “The Physics of Rebounding for Superspeed” we took an in depth look at the physics behind the force production necessary to change the direction of our hands and quickly create effective weapons. In case you have forgotten or missed Part 1, the take home message of all the fancy physics equations is:

The greater the change in directional speed of an object and the shorter the time frame in which the change of speed happens the greater the observed force must be.

Now that you’re here reading part 2, it means you intellectually understand this concept and are curious how to apply it to your Martial Arts training. Or you already use rebounding and wish to maximize its effectiveness. Allow me a moment to share the first experience I had of a rebounding happening in my body and me simply being along for the ride.

I remember it like it was yesterday. I had been told the principle before but still had to consciously think about how to apply it. It wasn’t something that just happened naturally. Because I was still thinking through each move within the attempt to rebound, everything was choppy without flow. That was up until around the time I was a purple belt working towards blue in American Kenpo. That’s when it changed for me. I was practicing the Parting Wings technique and I heard the rebound happen, and it occurred without conscious thought to make it happen.

For those unfamiliar with the Parting Wings technique, allow me to explain. An attacker tries to push you in the chest with both hands. In response, you step back with your right foot into a left neutral bow and do two simultaneous outward hand sword blocks. Then you settle into a forward bow with a right inward hand sword to the ribs. As the strike happens, your left-hand bounces from its previous block and recoils to your upper chest. It smacks against your chest at the same time your right-hand sword hits your opponent.

At the time of this smack, the body is rotating towards the attacker due to your transition from neutral bow to forward bow. The left hand then bounces off your chest with a smacking sound and is redeployed into battle and consequently very quickly strikes the adversary with an outward hand sword to the neck as you return to neutral bow. There is a more to the Parting Wings technique, but this was the very moment when my eyes were opened to rebounding and its potential applications.

After this realization, I started looking back at previously learned techniques and found that many of them also use this principle. For example, a few of my favorites that have rebounding applications learned at earlier levels in the American Kenpo curriculum are the purple belt technique Leaping Crane, orange belt technique Five Swords, and yellow belt technique Alternating Maces, among others.

If you are a Kenpoist and know these techniques, might I suggest you try working them through for a few reps and identify the rebounding opportunities. If you study an art that doesn’t utilize rebounding, revisit the described actions in the beginning phase of Parting Wings above and see if rebounding is something you can assimilate to enhance your hand speed.

Kenpoist or not, if you wish to incorporate this principle, it is important to keep an eye out for opportunities to effectively apply rebounding and practice, practice, practice. That’s what it takes to get good at any skill. And the greater our mastery of rebounding, the faster our strikes become and the more rapidly they can be consistently deployed. By digging back into our training techniques with rebounding in mind, we afford ourselves the opportunity to tighten up and improve our overall skill set as a Martial Artist.

After this realization, I started looking back at previously learned techniques and found that many of them also use this principle. For example, a few of my favorites that have rebounding applications learned at earlier levels in the American Kenpo curriculum are the purple belt technique Leaping Crane, orange belt technique Five Swords, and yellow belt technique Alternating Maces, among others.

If you are a Kenpoist and know these techniques, might I suggest you try working them through for a few reps and identify the rebounding opportunities. If you study an art that doesn’t utilize rebounding, revisit the described actions in the beginning phase of Parting Wings above and see if rebounding is something you can assimilate to enhance your hand speed.

Kenpoist or not, if you wish to incorporate this principle, it is important to keep an eye out for opportunities to effectively apply rebounding and practice, practice, practice. That’s what it takes to get good at any skill. And the greater our mastery of rebounding, the faster our strikes become and the more rapidly they can be consistently deployed. By digging back into our training techniques with rebounding in mind, we afford ourselves the opportunity to tighten up and improve our overall skill set as a Martial Artist.

Salute,

Ian Lauer

B.A. Chemistry

Dan Inosanto talks about friendship with Bruce Lee, mentions Ed Parker

Mr. Chapél on Bruce Lee and JKD

(a post from Mr. Chapél on Facebook, August 2022)

A reminder that Bruce Lee's JKD is not a style of martial arts any more than Ed Parker's Kenpo Karate. 

Both were designed to suggest students should follow a particular regimen to achieve the best outcome for the individual. Unfortunately, JKD doesn't actually set any parameters or even suggest specifics for encounters beyond a straight punch reflecting the rudiments of its roots in Wing Chun. This is not surprising considering Bruce's youth and time having a formal teacher, which was relatively short and done by the age of 18. 

A perusal of Bruce Lee's written works is mostly philosophical with much of his Tao of JKD being little drawings and quotes from other philosophers and was compiled after his death. Most of his written works surfaced after he had passed and most displayed essentially the same lead leg knife edge kick to the knee, back-fist combination trapping the lead hand. Classic Wing Chun. 

Although his association with Dan Inosanto brought additional knowledge to him, as well as with Gene LeBell, and others. Bruce's genius was his gift to assimilate physical movement, and he did that with everyone he came in contact with, while his celebrity students paid the bills. 

So in many ways, JKD is like EPKK. But, Ed Parker's version is light years ahead of the concept. By creating an actual guideline curriculum, and providing concepts of execution, as well as suggesting specific encounter scenarios, Mr. Parker was constantly pointing students in the correct direction while giving them the flexibility to tailor to their liking. None of this exists in JKD, and even Bruce's number one training partner, Dan Inosanto doesn't teach JKD, essentially because it only exists philosophically on a conceptual level. 

So in that sense, there is a definite connection between the two (JKD & EPKK), and Bruce's relationship with Ed Parker and others had a definite impact. It was even Mr. Parker who suggested Bruce Lee needed to learn to kick. Imagine that, but at the time Bruce only had Wing Chun experience with very limited kicking skills. So Mr. Parker sent Bruce to Sea Oh Choi of Hapkido over on 3rd and Fairfax, (in L.A. ) at the time and we (Cliff Stewart, Hugh Van Putten, and myself) got to watch Mr. Choi "teach" Bruce "how" to kick, especially for the movies. 

Mr. Parker said Bruce was a tremendous athletic talent, He said, "If you show Bruce something the first time he might do it almost as good as you. A second time he could do it as well as you, and if you weren't careful and showed him a third time, he might do it better than you." 

That was his gift, although he was not knowledgeable, he continued to grow and absorb from those around him without having a formal teacher. 

Had he lived, and if he had chosen to, he would have been a tremendous martial artist beyond the screen stuff. But, you see, Bruce was not interested in being the best martial artist in the world. Bruce wanted to be an actor, he wanted to be Steve McQueen, and had he achieved that status who knows if he would have continued to grow beyond the obvious screen prowess he already possessed. 

However, my biggest complaint about Bruce devotees is they tend to take his screen persona as real life instead of the "reel life" that it is. On top of that, the philosophy of training he espoused was major league flawed for anyone but himself. To do what Bruce did, you would have needed to have Bruce Lee's gift. Most do not. 

Bruce told people to throw away the inessential, but how do you know what is and isn't essential when you have no training and no experience? Interestingly, Bruce hated forms, but he did them before he discarded them, and is famously depicted in full Gung-Fu uniform on the cover of his first book doing a form. 

So Bruce gave good advice, but only from his own gifted and extremely talented perspective. Those significantly interested in Bruce Lee and his life should obtain a copy of Tom Bleecker's Book, "Unsettled Matters."

Chun-Li - Street Fighter kenpo

(from streetfighter.fandom)

Chun-Li is a world-class martial artist. She uses a mix of Tai Chi and Kempo. Earlier versions of the game erroneously stated her style to be Wu Shu. Many of her acrobatic moves do resemble this, but her actual attacks are based on the aforementioned styles.

Chun-Li's name is Mandarin for "spring beauty" (春 chūn, "spring"; 麗 lì, "beautiful"). It is properly romanized as Chunli in pinyin and pronounced "Chuen-lee", despite westerners commonly pronouncing it as "Chuhn-lee". The Japanese on'yomi rendering of the name is Shunrei.

Chun-Li's signature hairstyle is called "ox horns", a typical style in which Chinese children dress their hair; depictions of girls in Chinese paintings frequently show girls in ox horns.

Chun-Li wears a qipao, a Chinese dress imported over from Manchuria that became popular among girls during the early 20th century. Her outfit is modified to allow a far wider range of movement than a normal qipao. She also wears white combat/boxing boots of varying height (around calf-length in games such as the Street Fighter II series and older vs. Capcom titles, or around knee-high in games based around her 3rd Strike sprite) and a blue leotard with dark brown sheer pantyhose and a blue thong underneath with her qipao. Her qipao is blue with golden accents. She was originally supposed to wear a peach-colored qipao, as seen in her in-game profile and ending in the original Street Fighter II. Large spiked bracelets, whose ring is black steel and spikes are white/chrome polished steel are worn on both arms. According to supplementary materials, she wears the qipao in honor of her late mother, who passed away in her early childhood and whose only photo showed her in a qipao similar to her daughter's. The spiked metal bracelets she is known to wear are made of iron, and weigh approximately 7-10 kg (15-22 lbs) each. Chun-Li also wears them to help tone and exercise her body; the qipao is fitted with weights to help build body strength and finesse, while her bracelets are for the purpose of balancing her body when performing her kicking moves, including helping stabilize her center of gravity during a Hyakuretsukyaku and limit her during supers such as the Senretsukyaku to avoid overexerting her muscles. The spikes are also used for the purpose of intimidation.

link for t-shirt 

https://superareshop.com/

Nicki Minaj even did a rap/song called Chun-Li, although it has nothing to do with Chun-Li really. 

link to a clean version

https://www.youtube.com/watch?v=PsEB2rFGbSI

Kenpo Companion by Mr. Lee Wedlake

 (from Amazon)

Written in a uniquely accessible way and in-depth in its content, Lee Wedlake's Kenpo Companion is a comprehensive look at American Kenpo. With information from how to run a class to the intricacies of how the system is put together to real-life case studies of Kenpo in action, Senior Master Of The Arts Lee Wedlake, 10th Degree Black Belt, takes you through many different aspects of this unique and popular martial art.

Whether you are just starting out or are an experienced instructor, this is your must-have guidebook, and there is nobody better qualified than Lee Wedlake to be your guide.

(link to purchase)

https://www.amazon.com/Lee-Wedlakes-Kenpo-Companion-Wedlake/dp/B0BCSBNQX8

Grandmaster Villari

 (from the USSD Facebook page July 28, 2022)

It is with great sadness that we announce the passing of Grandmaster Frederick J. Villari a Great Figure and Legend in the Martial Arts Community and World Abroad. He was a Mentor, Teacher and Pioneer of the Shaolin Kempo Karate System. He will surely be missed and words cannot express the loss we feel today.

"Life and death are one thread,

the same line viewed from different sides"

- Lao Tzu

Mr. Kelly on extensions