What is Neijin (Inner Strength)?

Presented at the 17th World Congress on Qigong, Tai Chi, and TCM, Sep 3 2016, San Francisco, California by C.P. Ong Ph.D., Scientist of the Year Award 2016.

What is neijin?

Tai Chi Chuan (Taijiquan) practitioners harbor the dream of developing the magic of Neijin (Internal Strength). Neijin—the stuff of the kungfu prowess of Taijiquan—is mysterious because the art of Taijiquan resides in the internal, not characterized by the vigor of physical activities that we are familiar with. Neijin seems to defy physics, but there is no new physics.

A good place to start to understand neijin is at the waist, which is the source of power actions in sports, work and martial arts. Taijiquan’s term for waist power is specific, called dang-yao jin 裆腰劲, which translates as waist-groin power. The terminology indicates that the power is derived from the actions of both the groin (dang) and waist (yao). This involves the play of the pelvic platform, called the kua 胯, and Taijiquan places the greatest emphasis on the kua in practice. Indeed, the classics of Taijiquan1 are replete with references to the waist-groin region as the control center (Zhu zai yu yao … 主宰于腰).

The Biomechanics of waist power

In generating waist power, the upper body rotates in one direction, and the lower body turns in the opposite direction in support. Where should the division of the rotational motions between the upper and lower body be? If only the shoulder and chest were turning to power the upper body action, the rest of the muscles below would be underutilized, a common flaw. If the division of the rotations occurred at the knees, then the muscle mass below would have to support a much larger mass above, which would cause injuries to the knees or ankles. The division at the kua junction represents the most proportionate distribution of muscle masses between the upper and lower body, which can be seen in the power actions of Fig. 1 below.

Rotation power of the waist-groin.

Rotation power of the waist-groin..

There is another factor of anatomy. The vertebral column ends at the sacrum which sits on the pelvic (iliac) base at a flat joint, called the sacral-iliac joint (SIJ). The SIJ forms the hub of the transfer of forces between the upper and lower body via the three levers, the spine and the legs through the pelvic platform.2

The hub function of the SIJ has actually been observed in the classics:
If body cannot maneuver to take timely advantage (de ji de shi 得机得势), then the

problem is at the waist and legs (Qi bing bi yu yao tui qiu zhi 其病必于腰腿求之).

Force produced by the body

The body produces two kinds of forces. The first is the force of the contractile actions of the muscles, which produce motion. The second is the force that results when the body’s motion is resisted. This is the force the inflicts damage to the nose when the head stands in the way of the fist. We are cognitive of the motion but not of the force of muscle contractions. We are cognitive of force only when there is a change in the body motion (momentum).

The force that the body is cognizant of from Newton’s Second Law of Motion: Average Force = Change in Momentum/Time duration of the change.

The key to producing more force is to generate more momentum. Besides the obvious factors of increasing body mass and velocity, the issues of generating greater momentum involve:

  • The body segments moving in coherence
  • The alignment of muscle actions
  • The spinal rotation due to torsion from curvatures (the Spinal Engine)
  • The harmony of the fascial envelops of muscles and internal organs

Inner Balance

Taijiquan’s game plan to generate greater momentum is to regulate the body segments to move in unison. The traditional theory couches this in the principle of harmony—to be in accord with the Taiji principles of yin and yang. This yin-yang harmony pervades every thing Chinese—in food, arts, music, fengshui, etc. In Traditional Chinese Medicine (TCM) health is a good store of the life-force energy, Qi, circulating in harmony.

Taijiquan incorporates qi in the application of the yin-yang metaphysics to the art of body motion. But there is no quantitative analysis in Taiji theory to tell us what is the harmony of yin and yang. In the manifestation of yin and yang we can develop the cognition of excesses or deficiencies of yin or yang, and hence of yin-yang imbalance. In the musculoskeletal framework, we discern yin-yang imbalances as excesses or deficiencies of muscle actions underlying the body posture and motion.

We define yin-yang balance in Taijiquan, called inner balance, as a state where the muscle actions underlying the body posture or motion are not excessive or deficient. Once we have cognition of the errors of muscle actions, we can work to resolve them towards a better state of balance. But, even as this points to a pragmatic approach, we encounter problems. We cannot allocate so much muscle actions here and so much there to resolve the imbalance as in a scale balance nor are we cognitive of the muscle actions directly.

However, we can cultivate cognition and sensations of the effects of the errors of muscle actions. In a medical checkup, the doctor puts a stethoscope on your chest, and asks that you breath in. In doing so, the chest is heaved up, and the body becomes top-heavy, which falls easily with a gentle nudge. While the body is in physical balance, the abdomen is hollowed, weakening internally the support column of the midsection, and rendering the structure less strong in balance. The body can learn from the top-heaviness as an effect of yin-yang imbalance of muscle actions.

There are many varying combinations of muscle actions underlying a body posture and motion. What should be the preferred combinations of muscle actions for a given body posture or motion? Taijiquan’s answer is inner balance, namely, the combination of muscle actions with lesser errors. That is, the practice seeks states of lesser errors towards inner balance. But will the body listen?

Book cover of Generating Inner Strength Through Taijiquan

Book cover of Generating Inner Strength Through Taijiquan

Responses of neurobiology

The body is stubborn in its neural responses to recruit muscles, out of habits and convenience, which often turn out to be bad strategy or to bring harm to the body. For example in picking up a box, the hands reach out and the body leans forward. The back muscles fire by reflex to keep the body from falling over. In lifting the box, the weight pulls the body further down, requiring more muscle actions to keep balance. As a result, much of the muscle power goes to the reflex response to keep balance, and little to do the task at hand. There is no feedback of the debilitating effects of the muscle actions that cause chronic backaches. One could move closer to the box, bend down to lift the box with better leverage with the aid of the leg muscles in the same task.

Similarly, in throwing a punch, the muscles of the arm and shoulder tend to dominate. This dominance causes the arm to lunge forward ahead of the rest of the body, cutting the muscle power of the rest of the body to the punch. The body can learn to sense and associate the weakness of the punch to the lack of alignment of the muscle actions.

Although we are presumed to have control of the voluntary movements in the somatic nervous system, we have no direct control—we have no communication with the muscles. The control we have is only at the command level, at the top hierarchy of the motor system. This leaves a huge gap of neural activities between the command and the innervation of muscles that produce the motion at the bottom hierarchy. We have no cognition of any feedback in the gap to guide a preferred combination of muscles relative to the action of the command. Training is at the mercy of this gap of neurobiology.3

The responses of neurobiology work very well for bipedal balance and functionality, but not so in summoning the muscles needed to power performance actions in sports. Golfers have the comparable muscle masses to deliver long drives, but train as hard as they do, amateur players seldom can improve their golf swings in significant terms of a hundred yards. We cannot at will elicit neural responses to fire the right combination of muscles and we actually do not know which ones they are.

To overcome this problem, Taijiquan resorts to the yin-yang theory and qi via the yi-qi-motion paradigm:

Yi dao qi dao qi dao shen dong 意到气到气到身动 Command activates qi; qi signal arrives, and motion is activated.

In the response to the yi (mind) command, Taiji uses qi to signal the activation of muscles underlying the action or motion commanded.

Fangsong and Qi

We take Qi (气), the life-force energy, as given in TCM, but we can think of it as a composite of bioenergy, any energy involved in biological processes. The bioenergy becomes of great interest when it is accessible as biomarkers.

The first sensation of qi-energetics most commonly felt is tingling and warmth in the hands, due to increased blood flow or perfusion. However, Taijiquan relies more on changes in the bioenergy associated with the balance and alignment of muscle actions in the cultivation of inner balance. The experience of discomfort of tenseness or unease in a posture gives the initial sense of bioenergy that results from the internal imbalance of muscle actions.

To illustrate internal imbalance at a basic level, extend an arm out and hold it in balance. The arm is in physical balance but the muscle actions supporting it can vary, for instance, when stretched or drooped. Holding the arm up for ten minutes, tenseness and aches in the muscles would set in, which indicates excessiveness in some muscle actions. Upon sensing the discomfort, the body triggers a reflex response of relaxation, which brings some relief.

This response is called fangsong (放松), which is “to relax and let go.” The reflex response is operationally a reset of the muscle actions, which improves the support with less discomfort. This operation represents the rudiments of the tool, also called fangsong that reduces the errors of imbalances. The lessening of the tenseness by fangsong is accompanied by an ease of flow of motion, which sensation is cultivated as a biomarker of qi energy.

Fangsong is a process of practice that works to continually resolve the errors in the balance and alignment between the outer muscles that activate physical motion and the inner muscles that secure and stabilize the joints and structure. Fangsong restrains the outer muscles from dominating and allows the inner muscles to fire more, and thus to align in balance. The increased activation levels of the inner muscles at the hip joints in fangsong are often experienced as a surge of heat as qi.

At the advanced stages of practice, when qi is sufficiently developed, the fangsong tool relies more on qi as a medium to discern and resolve the imbalances. And the fangsong tool sharpens and refines organically to get at the deeper and subtler errors of muscle actions. In this way, the margin of errors tapers in the fangsong resolution, and the path eventually converges to inner balance.

In the meantime the yi-qi-motion paradigm is realized in the maturity of qi development. Following the yi-command, qi drives the motion forging the unity of qi dynamics (internal) and

motion (external)—nei wai jie he 内外结合. Thus, the yi-command at the top of the motor hierarchy transmits via qi to muscle innervation at the bottom in the discipline of Taiji motion.

Master CP Ong (front) teaching Tai Chi Chuan.

Master CP Ong (front) teaching Tai Chi Chuan.

The Kua Junction and Dantian Centrality

The training of inner balance involves resolving imbalances at the “hundred joints,” which is formidable enough, but what makes it even more formidable is that resolving the errors at one joint requires recalibration at the other joints because of the tensile integrity of the body frame. We find a practical and elegant solution to this seemingly intractable problem in the soft organic logic of yin and yang and qi.

Guided by the Principle of Three Sections and the Principle of Three Harmonies4, the many joints are subdivided into sections and correspondences of three for the fangsong resolution to work through systematically, and then through the further subdivisions in refinement. But more than a simplification scheme, the principles guide the transmission of motion through the joints and the harmony of the correspondences.

For instance, the fangsong in the correspondence of the shoulder and kua (pelvis) aligns and balances the torso, which unifies its motion and momentum. In the three-section division, the principle prescribes that the hand as extremity leads, which induces the the driving force at the shoulder as root, to transmit the motion through the elbow (as the middle section) smoothly.

In essence, the principles reduce the issues of the complex of “hundred joints” to the kua (pelvic) junction serving as a base of reference in the fangsong resolution. This reinforces the eminent status of the kua junction as the division between the upper and lower body in generating waist-groin power, discussed earlier. In practice, it means that the fangsong resolution becomes a continual play of muscle activations of the pelvic platform and of the SIJ and the hip joints.

Crucially, the constant reference to the kua is nurturing a centrality of motion at the midpoint of the junction, which coincides functionally with the dantian location. And this is at the same level of the SIJ. The centrality of the danitan affirms the SIJ as the hub of the transfer of forces between the three levers, the spine of the upper-body and the legs of the lower body.

In other words, from the perspective of practice, the fangsong resolution is cultivating qi that accentuates the centrality of the dantian—filling up the lower abdomen and concentrating at the dantian, which is called dantian qi. Thus, the practice of fangsong of the myriad joints is reduced to cultivating the fullness of dantian qi to establish the centrality of the dantian. The fullness of dantian qi signifies that the central status of the dantian is formed (yi dantian wei hexin xing cheng 以丹田为核心形成), and represents the mastery of the art. The establishment of dantian centrality bestows inner balance. The guiding qi in the yi-qi-motion paradigm is dantian qi, and the inspired motion is in accord with the Taiji principles. Neijin is born of this motion.


We conclude by summing up. Taijiquan’s methodology of fangsong-relaxation resolves muscle actions that are too excessive (yang) or too lax (yin) towards inner balance, and in the process cultivates qi energy. As qi develops more fully, Taiji relies on qi as a neural feedback to elicit responses that balance and align the underlying muscle actions. This regulates the many different segments of the body to move in unison and harmonizes the body’s internal momentum. Thus the ideal motion of Taijiquan is produced and the force that arises therefrom (by a change in momentum) is consummate—the force of neijin. This is summed up in the equation below, which paraphrases Chen Xiaowang: Neijin = Qi + Muscle actions

About the Author:C.P. Ong is the Executive Vice-President of the USA Wushu-Kungfu Federation. He a 12th generation Chen Family Taijiquan disciple of both Chen Xiaowang and Chen Zhenglei. He first began his Taiji studies in 1972 learning the Guang Ping Yang Style from Master Y.C. Chiang in Berkeley, CA. He is also a student of vipassana (insight) meditation and has attended several intensive meditation retreats in Buddhist monasteries in Yangon, Myanmar. He received his Ph.D. in Mathematics from U.C. Berkeley in 1973. Recent Publications include Generating Inner Strength Through Taijiquan, Int J Complement Alt Med 2016, 3(3): 00076, http://medcraveonline.com/IJCAM/IJCAM-03-00076.pdf and The Central Status of the Dantian, Cover Feature, Tai Chi Magazine, Spring 2016. Contact information: cpTaiji@gmail.com.

Highlights of Master Ong’s presentation at the 17th World Congress on Qigong, Tai Chi, and TCM.

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