A mystery of plantar arch 土踏まずの不思議
As karateka we are aware that most of us have a gap under the arch of our foot when we are in a standing position. The arch, the inner part of the foot is slightly raised off the ground and we know that this part is called the plantar arch or simply the arch. We feel so natural with the construction of our feet with this arch. We think nothing of this unless you happen to have flat feet or fallen arches. This means you have no arch, or the arch is very low (see illustration right). However, this does not necessarily mean you have a problem. They say that a significant number of people with fallen arches or flat feet experience no pain and have no problems. On the other hand, some do experience pain in their feet, especially when the connecting ligaments and muscles are strained. The leg joints may also be affected, resulting in pain. If the ankles turn inwards because of flat feet the most likely affected areas will be the feet, ankles and knees. We will not go into the problem of a flat arch as we are focusing on the mystery of plantar arch in this article.
I call this a mystery since we, as human beings are the only animal who have a plantar arch in their foot. Did you know this? If you did, then why do you think we have this peculiar construction? The more I learn about our body and its construction, the more I am convinced that someone great (called God by some) has designed our body and made it into a fine masterpiece. I truly believe this. It is true that most four legged animals such as dogs, horses, etc. can run faster than us. But look at all the skillful things we can do with our body using two legs such as riding a bike, skiing, skating, surfing, dancing, doing karate to name a few. Few dogs and horses can imitate any of those feats.
OK, let us go back to the subject of the planar arch. So the question was “why do we have this arch?” Believe it or not, it all comes down to the fact that we are the only mammal that walks on two legs. You may say, “So what?” I know most of the people are not very interested in this subject as they are not aware that this fact can be critically important. In fact, just knowing this fact itself may affect the way you move your legs and specifically your feet. Let me explain how this will affect your physical movements, but first, let us review how the leg constructions of a man, a dog and a deer leg (see illustration left) to see if there are any differences. Isn’t it interesting? Yes, indeed it is.
The first one, of course, is a human. We know how we stand and what the bone structure looks like. The second one is the rear leg of a dog. The third one is that of a deer. So, now you can see the differences in the bone construction. What differences do you see? Yes, our leg is straight whereas those of a dog and a deer are bent or crooked. Is this important? Yes, it is but I will explain why it is important later. What else do you see that is different? Do you see the lines with the bone structures of a dog and a deer in the illustration above? Those lines, believe it or not, show where their heels are.
Look at the photos below so you can identify clearly where the heels of the rear leg are located.
What do you think? Their heels are located very high and they do not touch the ground like ours do. It is like the right leg (bent one) in the photo of a human leg. If we walk on the ball of the foot then we will be walking like a dog or a deer. Our feet get tired very quickly so we cannot walk in this fashion for a long period of time.
However, it looks like the ladies like this style of walking more than men so they invented the special shoes, high heel (photo right). These shoes certainly make you taller and your legs look longer. However, we hear about the possible harm from wearing this type of shoes for a long time. We will not go into this subject as we are focusing on our feet in a normal standing posture. So, back to the photos of a dog and a deer above. A dog stands on their paws which is equivalent to the combination of our toes and the ball of a foot. In the case of a deer, they have a hoof. A hoof is the tip of a toe of an ungulate mammal (such as horses, rhinos, cattle, etc) strengthened by a thick, horny, keratin covering. In other words, they are walking on their nails like ballerinas attempt to do. But look at the toes and the nails of a ballerina here (photo left). Obviously this way of walking is not fit for us.
Also, notice their front legs are rather straight, similar to our legs. Though the heels of the front leg are not touching the ground they are much lower. This is important and we need to find out why.
Let us look at the bio mechanics of those animals (our samples are a dog and a deer). Comparing their front leg and the hind leg, it is obvious the hind leg has bigger muscles which means it is used mainly for acceleration when they run. Of course, they also use the front leg by pulling (the best example can be seen in the running of a cheetah, the world’s fastest land mammal) but the main power comes from the hind leg pushing the ground. So, the front leg is used more or less for balance and the leg does not need to be bent at the knee.
Would a dog put the heels of the hind legs down to the ground? Yes, it does but that is when it sits down or to balance itself as it lifts the front legs up (photos right). These positions are definitely not for action or a quick movement. When it wants to jump forward, it will bring its rear up and lower the front. A cat usually show this position before it jumps after a mouse or a squirrel. The front legs are also bent as it needs to bring the rear higher to bring the momentum forward when it starts to run. The photo on the left is a big cat showing it is assuming the position to pounce on its target.
OK now you may say and ask, “I understand the bio mechanism of a dog and a cat. But what does that got to do with us, especially with our karate?” Thank you for asking as I was waiting just for this question. This is exactly where I am going.
Here is an interesting photo (right) that I would like you to take a look at. What do you think? Yes, it is the starting position for a short distance runner. So, when you want to maximize your acceleration at the start you have to get down to this position looking like a big cat above. Doesn’t this tell you something? To move quickly, it is better to be (at least at first) down on four legs.
Now you may say, “OK I understand that the four legged animals have a ready to run position even if they stand still. I also realized that humans in order to have a quick start in their sprint run, it is better for them to crouch down and get their hands on the ground. But, what does this got to do with our feet and especially the planar arch that you are supposed to explain to us?”
Wonderful, now I can get in the real subject and, I believe, I am the first person to introduce this subject to the karate world though it may be well known in the medical or sports science world. You may or may not agree with my theory but let me explain how our feet are functioning for us.
When we decided to lift our front legs up hundreds of thousands of years ago and started to walk on two feet, we (or our Creator or Designer) made a remarkable adjustment or modification to our feet. Yes, it was our planar arch! How? OK let’s take a close look at our foot. The illustration (left) explains that in fact there are three arches in our foot. This is a very interesting and the key point which I explain later. Now, if you look at the bone structure you can see that we have two parts in our foot that contact firmly on the ground: ball of the foot and heel. As you are a smart reader you can probably guess what I am going to propose here. Yes, those two contact points are functioning as the front foot and the hind foot. To be precise, we have three contact points instead of only two (points A, B and C). This is amazing in that, if trained (this is the key word), we can have four front feet! We normally do not train our conscience and our body to differentiate the contact points in the ball of our foot. Most of us consider it as one spot, the ball of the foot (right). When you reach the expert level of dancing, ballet and athletes such as football, basketball and even track and field, the expert knows the difference and he/she uses those two points differently. Certainly, a martial arts expert should know this too. Though you must use both points (A and B) of a ball of foot, I recommend that we should prefer to use point B rather than A when you are moving forward. I will not go into the details of this in this article. Maybe in the future, I will write a more thorough article on this very point with the detailed explanation why it is better. Regardless, the “Designer” of our body allowed us to have four “feet” and we must remember that we can do some incredible body movements because of this fact. By skillfully manipulating these 3 points on each of our feet, we are able to do some complicated body movements such as dancing, figure skating, skiing, gymnastics and martial arts.
Even if you do not pay attention to the two points in the ball of the foot, I hope, at least, you agree that we have two contact points: the ball of the foot and the heel. Then, what is next? I want you to compare the rear leg of a human and a dog again (below left).
So, when a dog has to stand on the rear legs alone, what does it have to do? It sits down by bringing its heels down if it has to maintain the balance (below center). If it has to move forward (moving backward is almost impossible for it) it certainly cannot walk like a person so it has to hop. Right? It hops with both legs together (below right).
So how does this tie in with our karate movements? How does a dog hopping relate to karate? I will attempt to explain here.
Recently one person asked the following question. He said he had gotten into kumite competition in the 80’s. He learned the free sparring style with the hopping foot work as we commonly see in the WKF tournaments. In other words, the competitors are either standing on the ball of their foot or hopping (below left). However, as he watched the JKA kumite videos from the 60’s, the 70’s and even the 80’s, the competitors stood in a “flat foot” position with their heels firmly planted on the floor (below right)
He asked why and how this occurred. Here is my answer to his question. In 1981, our karate (specifically the JKA kata and kumite) experienced a change. I will talk about only kumite in this article. In 1981 JKA joined the JKF (Japan Karate Federation) so that the JKA competitors could compete, for the first time, in the 36th Kokumin Taiku Taikai (国民体育大会 All Japan National Athletic or Sports Festival) or Okutai (国体) which was held in Shiga Prefecture (滋賀県) in that very year. I know this because I was one of the competitors and represented my prefecture, Hyogo (兵庫県). Luckily I won first place in the JKA Hyogo Prefecture championship that year and captured the opportunity to participate in the athletic festival. I was, of course, a traditional JKA competitor with my feet flat on the floor so it was a little shocked to witness the hopping style kumite that had already been adopted by the Shito-ryu and other styles competitors. The JKA competitors had to change their fighting style because they could not win with the flat foot style. Let me explain why they could not. It was certainly not because the JKA competitors were slow or less powerful. We simply found the kumite rules were different. There were two major differences, though those two are somewhat interconnected. Let me explain. The first is the distance and the second was the power (or lack of it). We were strictly prohibited to touch or make a contact on the opponent especially in the jodan area. Even if it was a light touch to the opponent face, you were automatically disqualified. To the chudan area, it was similar though a very light touch was tolerated. Even if a fist is one inch away (with a fully extended arm) it
was considered waza ari. As you know, in the JKA kumite you basically have to be “there” to get a waza ari point. Bleeding nose and lips were very common and nobody got disqualified even if a competitor knocked his opponent tooth out. The second was the posture and the power behind a technique. In other words, the technique had to be “heavy” meaning the technique (tsuki and keri) had to be supported with the whole body behind it. If a punch is thrown with a fully extended arm but the body was turned sideways, it would not be considered as effective or waza ari. The techniques that were allowed in the Kokutai tournament were very light to me. Jumping in and throwing the arm out quickly seemed to be enough to win a point. The techniques I was familiar with was one punch one kill kind. On the other hand, at Kokutai the techniques were fast and light. From that perspective, it made sense that the competitors were hopping. So, remember that this hopping movement by a karate competitor is based on the same bio mechanism as a dog that has to hop with both feet together if it has to move forward or just to move around.
If you happen to practice kendo (剣道), you may say “In kendo we lift our rear heel up even though we do not hop.” This is true. I have to say, with due respect, kendo’s techniques had become sport like even though they say that they keep the budo spirit. I am not a practitioner of kendo or kenjtsu but I can say this from my understanding the concept of budo or bujutsu. This is important so I will explain it further.
In Gorin no sho (五輪書) written by a famous samurai, Miyamoto Musashi (宮本武蔵), there is a statement that puzzled the modern day kendo practitioners. Musashi wrote that the heels must be firmly planted on the ground when you fight (with swords). In other words, he warned practitioners not to lift their heels up while assuming kamae and attacking. This statement was a puzzle as the kendo practitioners now lift their rear foot (typically their left foot) or heel off the floor (below left). If you look at the koryu kenjutsu (古流剣術 old time swordplay art) or Iaido (居合道 sword drawing art), you notice two differences (below right). One is the distance and the other is the heels. The distance in koryu kenjutsu where they practice with either a real sword or a wooden sword is typically much further than the distance that is used in kendo. In kendo they are already in close ma-ai (間合い distance) where one can strike the opponent by taking one step forward. Why? It is simply because there is no fear of getting cut by a sword. You may feel some shock to your head if you get hit by a shinai (竹刀 bamboo sword) but the fear factor is tremendously less than when you are facing a person with a real sword. The heel is up, obviously for a faster jump in which is the same reason why WKF competitors stand on the balls of feet. In kenjutsu and Iaido, the heels are down as their cuts are “heavy” with their full body weight behind thestrike which is the same concept as the karate punch and kick with kime.
We walk on two legs (bi-pedal walking). This is very unique as we are the only species that does this among the mammals and at the same time it requires fine balancing. Think of riding a bicycle. You can keep balance easily when you are moving forward. It is tremendously difficult once you stop your bike but try to keep the bike balanced without your feet on the ground. As we have been walking since we were one year old so we feel it is almost natural to be able to stand up and walk. However, we must remember it took us one year or even longer for some to acquire bi-pedal walking ability. I wrote a chapter on this particular subject, “Unstable balance” in my book, Shotokan Mysteries.
To compensate for lacking front legs, we now have a planar arch to create a ball of the foot. In fact, we have two contact points (#2 and #3 in the photo below) in the ball of a foot. If we can consider that the heel (#1 below) is a hind foot then we now have two front feet in each leg (four front feet!). This is not a joke. By being able to manipulate and use their “feet” we are capable of doing some intricate bodily movements that are impossible for the other animals such as dancing, figure skating, gymnastics, martial arts, etc.
In sports karate they have different objectives, thus the players hop on the ball of the foot. In budo karate, as we do in our kata, we must learn to keep our heels firmly on the floor. At the same time, we must learn how to move forward, backward and to turn using the correct parts of our feet. I wrote a chapter in another book of mine, Shotokan Transcendence about turning. If you are interested in this subject, please find the chapter, “What part of your foot do you use when you turn?”
The more we find out about our body and its incredible design, the more we appreciate what we have and the tremendous potential of what we can do with our body.
I look forward to receiving input from the sports scientists and/or kinesiology specialists on the points I described in this article.