Well, most traditional martial artists like to call this chi gong or Taiji Chuan or internal power, but I’ll use the more Westernized labels and translations, of my own devising. Since they make more sense to an English native audience, including myself on that matter.
Now the number one issue most people have when they start on this path, is leg conditioning and training. The legs are the power we normally use and stand on, to resist the gravity pull of the Earth on our upper and lower masses. So for a beginner, that’s where it starts, and for internal power as expressed in martial arts, it’s also the source of the power so to speak. The other source is your center of gravity, the dantien or middle of your guts and lower spine.
In the purely physics dimension, this doesn’t include any hidden or mysterious energies, we’re just dealing with gravity for the moment. And gravity, at least, is something Westerners have been taught a lot about. It is part of their paradigm in a way that power from the air or power from feeling/neural electricity, isn’t.
On the Chinese side, the beginning stance for a lot of leg conditioning is mabu or horse stance. Meaning, stand as if you are riding a horse… which could be a problem for Westerners that have never even seen a horse let alone stepped up to mount one. Most modern horses have stirrups attached… well attached somewhere, not a horse expert here. The stirrups hang down from near the saddle, so there’s nothing underneath the stirrup holding it up, so when you step on it, you are basically dragging it from its attachment point, which doesn’t move probably because it’s attached to the saddle, your seat. And the saddle is attached to the horse. What this means is that the stirrup is slippery, when you step on it. You have to direct all your weight in a straight vertical vector down on it, without wiggling else you might just push the stirrup to the side, slip through with your foot, and start getting dragged by your stirrup attached to your foot as the horse walks around in horror. Steppe barbarians and nomadic archers didn’t have stirrups, they invented them and later it got passed on to the Byzantines and the Westerners. A steppe archer can shoot his bow, on a horse without stirrups or saddles, merely via the power of his legs and thighs.
Cutting a long analysis short, the point is that when you step up to mount the horse, you need your legs spaced wide as in the mabu, but you also must direct your weight so that it becomes a vertical line through the bottom of your feet. If your begins sliding out from your base, like you’re doing a split, then you need to pull them back together using your inner leg muscles. Which, presumably, are the ones that kill people when they start using them, since they normally don’t use that when running or walking. Only skaters or ice skaters might use them or people walking on very slippery surfaces.
Theory about using gravity as an internal power source sounds simple perhaps, but the details are rather messy and complicated, as it would be for most other physical activities rather than abstract studies.
So that is perhaps why the Chinese internal masters stood on one leg, like a crane, all the time, with their body structured as if it was stone.
However, there’s a problem. Merely stabilizing your mass vector down or up, doesn’t give you horizontal power. Unless your enemy is right below your foot or right above your head, you can’t project energy into them if you cannot channel vertical vectors from gravity into horizontal vectors of force. That’s another tricky part when it comes to body mechanics, because the human body is made out of “Gears” or what doctors like to call joints and other connective tissues. For each joint which separates the point at which gravity powers flows into your body, to the point where it separates from your body, any malfunction can dissipate and eliminate that power.
To put it another way, if you jump on top of someone’s stomach, and assuming your weight is directly completely in one vector down, concentrated, that is using the power of gravity, your entire mass, and accelerating it at 9.8 m/s/s into the target. Internal power in martial art or neijia, seeks to take that foot drop and convert it into a horizontal attack vector force that channels and deposits the resulting power from the legs to something else.
However, your hands and shoulders are not designed to do that. You are not a monkey. Your legs and foot may be used to the stress of supporting your weight against the earth’s gravity well, but your hands are not. Especially one handed, like a punch. For each joint that exists in the human body, ankles and wrists including, is a potential failure source. Most people fail to generate the power or they fail to channel it. But if they did successfully channel it, they could just as easily break their own bones or joints or something else valuable, because they failed to resist the flow of power. Force flows in the direction with the least resistance, after all. You can shoot a bullet into a concrete wall, but that doesn’t mean it won’t bounce the bullet back into you, just because the bullet is traveling very fast. Sure, you can bring enough explosives or powder to penetrate even concrete, but if you are standing near the explosion, you also get blown away. So people use shaped charges, to shape the force in one direction. With det cord, even if the shaped charge fails, the user is safely some x miles away. With internal power, that doesn’t work. You are basically connected to the explosion of your power, by touch. There’s no shockwave in the air which allows you to connect distant target to your source of power, like a detonation cord would. Sort of like how a vacuum doesn’t transmit the shockwave from a nuke very well.
One of the first sets of feedback I got which verified I was using some kind of power, was that when punching air, my shoulders started to hurt. And when I fixed that, my elbow and wrist started to hurt. And when I fixed that mechanically by changing body techniques, my fingers hurt. What the Chinese call fajing or power projection. Air has little resistance, so whatever energy you put in there, just goes back into your body. Which is why the joints hurt, they are being ‘pulled out’, literally. For the shoulders, it’s normally just blowback when people tense them up and hench them, instead of seating the shoulders down like a socket or nail making a board flat. There are other ways of testing power projection, such as breaking boards or transmitting a shockwave through one material and destroying another material behind it. Although at a certain point, your hands start being destroyed, if the target is significantly harder than it. Which is why some people use iron palm conditioning or basically, deadening the nerves and increasing the strength of the hand tissues through constant repetition of trauma and impact. The neijia users probably just goes with the flat palm, like when a person does a hand stand or puts the palm down on the ground to stop them from face smashing. Less absolute reach distance compared to hitting with the fist, but you’ll still have a working hand after a few hits.
So normally after a person works on their legs, they work on their hands. Or it may be even vice a versa. External conditioning of the arms to create better hits, and then better leg conditioning to increase acceleration/de-acceleration when moving into and out of range of the enemy. Those two elements, the base foundation and the end point where the force projectile comes out of, tend to be the most focused on by beginners, whether for practical or cultural reasons. For boxers, they call it “hand speed”. The ability for your hand to accelerate and travel from your guard to the target in x seconds. Neijia users don’t always need hand speed for offensive, since they can just close the distance by using their legs, along with their hands. Or bump into someone using the shoulder, and use that as the point of power expression, impact, explosion.
The elbow is the next tricky proposition for people to work on, probably between beginner and intermediate. Between walking and running. Or between walking and swimming.
After that is the shoulders, which can be really difficult as most people are not aware of how their shoulders move or even that they are moving them.
Then the back and the spine.
From the point of view of the legs, it’s the foot first, the knees, and then the hips. Hips > Knees > foot in terms of ease of learning, from my pov. Gross motor to the more delicate, dexterity control needed via skill.
People have probably noticed that I haven’t said or written a word about techniques to use, other than to refer to them indirectly. That’s because from a certain of point, you don’t need an over complicated technique if you have the basic foundations which allow the channeling of gravity based power. Just as someone stronger and bigger than you doesn’t need technique to make you into the equivalent of a junkyard compacted car. Power is power, even in the hands of the inexperienced or incompetent.
Of course, many users of weijia or neijia, external and internal power sources, are not satisfied to stopping with the fundamental physical conditioning portions. They want the technique, the philosophy, the Way of Life, even, attached to this power, not merely the basic elements. Human ambition, so to speak. But once you know how to mix your own colors and have something to paint with, what you do next is really up to you.
For the background and subtext on vectors, this post I wrote covers it somewhat.