by E. Paul Zehr
Unless you actively practice martial arts or other activities like gymnastics, you don’t really spend much time each day thinking about your center of mass. The center of mass, also called the center of gravity, refers to the central point on an object or body through which the force of gravity acts. If you were a big sphere of a material with constant density, your center of mass would be right in the very middle. However, since you aren’t a sphere and you don’t have constant density (your bones, muscle, and connective tissue all have different densities; think back to Chapter 1 when we talked about body composition), your center of mass isn’t as easy to locate.
Having said that, we can consider your center of mass to be roughly near your belly button in height above the ground and approximately in the middle of your abdomen. When you are standing we can imagine a line of force because of gravity acting straight down at this point.
To get a feeling for the idea of stability and base of support related to the position of the center of mass, you can do your own simple test. If you just stand up and assume a posture where you feel stable, your center of mass is within a base of support defined by where your feet are. If you are standing with your feet slightly apart and on the same line, your center of mass is right between your feet. That fact that you aren’t falling over (and aren’t holding on to anything for support) means that your center of mass is within your base of support. Now, start to lean forward slightly. As you continue to lean forward at some point you will feel yourself go off balance and will try to correct for this by stepping forward. It is at that precise moment where you felt the need to step forward that your center of mass strayed outside your base of support. In throwing someone you are trying to manipulate that exact scenario in order to tumble them to the ground.
As with other aspects of the human body we have examined in this book, you might be surprised to know that you are creating and storing energy when you stand still. Can you recall our discussion of potential and kinetic energy? We discussed a rock pushed to the top of a hill. The movement uphill was kinetic; when the rock reached the top of the hill, it was storing potential energy and just needed a little tap to roll down the hill rapidly. This concept of energy can also be seen in the first law of thermodynamics: energy is neither created nor destroyed.
So when you are standing still you are storing energy. This potential energy is calculated as the mass of the object times the height of the object above the ground times the acceleration due to gravity. The force of gravity has the potential to do work on this object, in this case a person, and the act of falling is the conversion of the energy from potential to kinetic energy.
By the way, you make use of these principles every day even if you aren’t a martial artist or a gymnast. The “simple” act of walking really involves continually pushing your center of mass outside your base of support and then catching up to your falling body with a subsequent step. Think about the—probably infrequent—times when you have fallen while walking. Usually something happens to one of your feet that causes a trip or prevents a forward step, thus keeping you out of your center of mass and off balance.
Well, throwing in martial arts just means basically doing those things on purpose instead of having them occur accidentally. Kind of accidentally on purpose, you might say! Figure 10.2 shows an example of this taken from “The Batman vs. The Cat-woman!” (Batman #3, 1940). In the first panel, the bad guy can be seen trying to plunge a knife downward into the Dark Knight. However, Batman grabs the wrist of the attacker and then, without stopping the downward projection of the blade, swiftly turns his body and pulls the arm farther downward. This extra pull is the concept of adding forces together we talked about already. The next panel shows how the attacking fiend is now thrown off balance and crashes to the floor. The figure also shows a cartoon schematic of judo’s seoi-nage (hand throw). It is easy to see when looking at these drawings that Batman really was applying basic judo principles in his early encounters.
They All Fall Down
Batman seems to get thrown almost as much as he throws Gotham City’s worst. Let’s look at why he doesn’t get seriously injured from the falls. One way we can think about it is to examine what happens to professional sports entertainment performers such as those in WWE to keep them from injuring themselves when falling. Sure, the throwing and scenarios leading up to throwing in the wrestling bouts may seem to be and probably are contrived. However, the performers are actually thrown through the air and actually land on the canvas. How is it they (mostly) emerge unscathed?
Figure 10.2. Batman does judo (top). The bad guy can be seen trying to plunge a knife downward into the Dark Knight. However, Batman grabs the wrist of the attacker and then, without stopping the downward projection of the blade, swiftly turns his body and pulls the arm farther downward. You can compare this move with the cartoon schematic (bottom) of judo’s seoi-nage (hand throw). The arrows show the main points of overlap between Batman’s move and a real judo throw. Top panel from “The Batman vs. The Cat-Woman” (Batman #3, 1940); bottom panel modified from Imamura et al. (2006).
The basic concept is actually rather simple and relates again to the concept of transfer of energy from potential to kinetic. Recall that before being thrown, the opponent is standing and has a certain value of potential energy. When he is thrown, the energy will be transformed into kinetic energy. If that energy isn’t used up or dissipated, it can cause injury. So we will have to discover a way that the wrestlers and Batman dissipate energy when they throw or are being thrown. Bear with me, I promise we will!
Think of the way racing cars in NASCAR or Formula 1 racing seem to almost disintegrate—except for the cage protecting the drivers—in an accident. This is so the huge energies involved in any crash can be dissipated or taken up and dispersed into breaking up the vehicle and not breaking up the driver. Well, break-falling in martial arts (yes, this does mean how to break your fall!) is quite similar in principle.
Two main classes of techniques protect your body during a break-falling movement. One—the roll—is for use in those times when your body is projected outward (you go sideways) and the other—the break-fall—is for those times in which your body is projected downward. Breaking the fall is really about spreading the energy of the throw and the ground contact forces over as large a surface area and as large a time as possible. So our wrestlers will land as slowly and as spread out as possible. They wouldn’t want to land quickly on one foot or hand!
The forces of these throws are actually pretty large. If Batman is thrown over Catwoman’s shoulder, he would find the ground hitting him with a force of more than 5,000 N (more than a thousand pounds)! And that is the calculation if Catwoman just drops Batman from her shoulder and doesn’t actually throw him down. Breaking up this force involves having as much of the body as possible in contact with the ground. It also involves actually striking the ground on purpose with the arms and legs. There are therefore two actions occurring. One is to try to generate a large impulse (recall that impulse = force × time over which the force is applied) the other is to reduce the pressure (remember that pressure equals force divided by the area of applied force). To accomplish these things a judo expert like Batman will “roll with the forces” and strike the ground deliberately. This striking the ground creates an opposite reaction force to that experienced in the fall and helps to reduce the overall magnitude of any force involved when the whole body contacts the ground.
This can be seen many times in Batman comics. My favorite example is found in “Paint a Picture of Peril” (Detective Comics #397, 1970). As we read at the top of the panel “Batman’s intensive judo training serves him well! He wills his body to limpness and, at exactly the proper instant, twists to land on his shoulders and forearms.” He is then seen to perform a kind of back break-fall. Hitting the ground with his hands and forearms is what helps break the fall. It is clear that Batman knows how to throw and fall and to strike with great power. A well-trained fighter like Batman reall
y can bash as well as be bashed. We’ll talk more about the cumulative effects of getting bashed in Chapter 13. Before leaving this chapter, though, we should address the question: Where should Batman bash?
Where Should the Bat Bite?
Batman can clearly strike with great power and is skilled at applying joint locks and throws. (For those of you new to martial arts, I will explain the art of joint locking later in the chapter.) But where exactly, should his attacks be aimed? Is it OK to just hit anywhere or are certain places better than others? Clearly knocking his opponents unconscious would be great. However, that is really hard to do, and directing blows to the head carries with it the high potential for mortal injury, which we know from Chapter 9 that Batman wants to avoid.
Choosing where to strike comes down to attacking weak points in the body, of which there are actually quite a few. Some are pretty obvious, some less so. I want to discuss two kinds of attacks on weak points, striking weak points and using weak points in the skeleton for joint locks. We can categorize the weak points in a variety of ways. By the way, some of the things we’re going to briefly talk about here have gone by names like pressure points, vital points, or even the fear-inducing “death touch” in some overly hyped martial arts traditions. However, I prefer weak points because all of these things are literally parts of the body that are weak and exposed to attack. If I asked you to name weak points that would make good targets on the body, my bet is you would have groin at the top of the list. This might be followed by the throat and the solar plexus (that part of the chest just below the breast plate. You may know the last of these as the little bit you are not supposed to push on during CPR). Those are obvious ones for sure. You might not have thought of the armpit, the shin, the top of the foot, the inside of the arm, the outside of the thigh, or the small of the back. However, these are all weak points.
Weak points are places that cannot be made strong (so groin, throat, bridge of the nose), places where nerves run very shallow under the skin, or parts of the body that only move in certain ways.
Figure 10.3. Some weak points of the human body.
Figure 10.3 shows a simple diagram of the human body with some superficial weak points marked out. This kind of diagram can be found in many martial arts books and can be much more detailed than this one. These weak points and ways of attacking them are included in many martial arts systems. In Chinese arts they are often called chin’na, and in karate they are often referred to as tuite or kyusho. These terms refer to the general idea of kneading, striking, and impacting these weak areas.
When considering nerves as weak points, all you have to think about is your “funny bone.” We have all smacked our elbows into something and had that sharp jarring pain plus tingling in our arms. Well, you don’t have a special receptor in the elbow just for smacking on things and then informing you that you just smacked your elbow! Depending upon where you smack your elbow, you are activating the nerve fibers from the ulnar and median nerves that bring information to and from the skin and muscles of the forearm and hand. Well, attacks on weak points in the body where other nerves come close to the skin make use of this same basic idea. The reason they are so effective is that they are being attacked with great force and high pressure (as we discussed above), and the connections in the spinal cord that are activated evoke powerful reflexes that help destabilize an attacker.
Think of the top of your foot. Have you ever accidentally dropped a hard object (maybe a jam jar or something) onto the top of your bare foot? If you have, you may recall that you pulled your foot away from the jar after it hit your foot. Well, what would happen if you were standing on that foot when that happened? Now imagine that you are at least allowed to have a sock and shoe on but instead of a jam jar it is Batman’s hard heel? You would fall down, of course. Batman has to exploit these weak points to be an effective fighter. And he does do this in many of his encounters. A clear example of this is found in the Batman Broken City story arc. Batman is relating one of his dreams (or nightmares really, since they center on the night his parents were killed) how he would disarm an opponent. He is certainly making good use of exploiting weak points in a similar ways to those in most fighting traditions when he says, “I know exactly the right bundle of nerves I need to squeeze to make him drop the gun.”
Now let’s turn to weak points in relation to joint locking. There are many different joint locking techniques that can be used on the arms, legs, head, and whole body. However, they all adhere to a very simple set of principles. These are to take the slack out of the arm (or leg, or . . . ) and make the joints bend in directions or ranges they don’t normally go.
So, imagine a “simple” wrist lock. If you want to lock to the wrist, that is, focus the discomfort on that part of the body, you have to be aware that the hand is the handle but that the arm is pretty much a big bungee cord. You can twist the handle but all the energy in the twisting is going to be taken up all the way along the hand up to the shoulder. So, the hard, forearm, arm, shoulder, and posture of the attacker all have to be manipulated by Batman to effectively cause discomfort in the wrist that will force the Joker to drop his gun. Now that the slack in the arm is taken up, Batman twists the wrist in directions that it doesn’t normally go. Your wrist is a bit tricky in how it moves. You can bend it up and down, side to side, and turn it over. So, that means all of these directions have to be taken into account in joint locking.
Gently try this on yourself. Place your right hand so that it is palm down. Now take your left hand and grasp your right then bend the right hand down as far as it will go. If you keep pushing, it starts to hurt, right? But your wrist can also twist. So, keep some gentle light pressure to keep the bend, but now twist your wrist and then lightly push on an angle. What you should notice is that this hurts a lot more! What you have done is remove the slack (this is actually reducing the degrees of freedom, but let’s keep it simple) from the wrist. You have now activated nociceptors, or pain signals, that we look at more closely in the next chapter when we discuss steps Batman takes to minimize pain and injury from battling crime.
So actions like joint locking help give Batman victory! That is pretty much all there is to it. Of course, applying a joint lock on a hostile opponent like Bane is maybe not quite as simple as that!
CHAPTER 11
Hardening the Batbody
CAN STICKS AND STONES
BREAK HIS BONES?
The suit had power . . . I could barely move in that suit. To this day, one hip has not been right because I practiced when I first kicked that guy on the roof, and it was very difficult to get my foot up that high. It was like fifty thousand rubber bands holding you down.
—Michael Keaton, quoted in Batman: The Complete History by Les Daniels
If you are going to make your living engaging in mortal combat with evildoers and ne’er-do-wells and you refuse to give yourself the offensive equalizer of something like a gun, you might want to beef up your defenses. Well, in all truth, Batman is the ridiculously wealthy Bruce Wayne. He doesn’t actually make his living doing that. However, it is a pretty obsessive hobby at best. What advantages can Batman try to give himself for his moonlighting adventures? I’ll discuss two main ones in this chapter. One is to harden his body by training, and the second is to harden his body by using a special suit—the batsuit.
There is a process that exists in many old martial arts traditions, particularly those coming from China and Okinawa. It involves training and conditioning body parts to be strong and resilient. It has been called “body hardening” and “body conditioning” and has been used for the hands, feet, shins, forearms, and even the forehead! Severe training in these methods can condition the body to the point that you can do extreme things like break baseball bats in half with your shin or smash concrete blocks with your head.
Now, would Batman do this kind of training, or not? Is it a good idea to do this training in the first place? While it does hurt to do this training, we also want to know if it
is harmful. We learned in Chapter 5 that bones respond to exercise stress, and in Chapter 10 that bones are strong enough that hands and feet can be used to break boards and concrete. Is a special method for training bones needed and, if so, how would it work?
The Method of Body Hardening
So, I’ll be completely honest here: the basic principle is very, very simple and quite obvious. It really amounts to continually banging the body part that is to be conditioned against a hard or coarse object like a wooden post. There are many advanced aspects to this, of course. Just as with any kind of physical training (such as we discussed in Part II) the approach is related to gradual progression of the stresses that are applied to the body. This allows for gradual adaptation to the stresses.
Many difficult forms of this have been described for different martial arts and often been closely related to Shaolin martial arts. For example, David Chow and Richard Spangler detail the process of “iron fist kung” where the hand must be repeatedly bashed into small pebbles, then rocks of increasing mass until punches are against 45-kilogram (100-pound) stones. The images in Figure 11.1 are from their book describing ancient and esoteric Chinese martial arts training called “hard chi kung.” On the left side of Figure 11.1 this method is shown for conditioning the head, and the image on the right illustrates a technique called “iron broom kung,” with a person conditioning his foot by hitting it against a tree. The main point is that the body part (head or leg in these examples) is repeatedly struck against other hard objects in an effort to “harden” and condition them.