Neijin

In advanced traditional Chinese kung fu (martial arts), Neijin (Traditional Chinese: 內勁; pinyin: nèijìn) refers to the conscious control of the practitioner's qi, or "life energy" via strengthening self physical posture, to gain power delivery capability and efficiency advantages in combat.^[1] Nèijìn is developed by using "Neigong" (Traditional Chinese: 內功; pinyin: nèigōng) (內功), or "internal exercises," as opposed to "wàigōng" (外功), "external exercises."

Li vs. Neijin

Practitioners of kung fu refer to two separate forms of personal force: Li (Traditional Chinese: 力) refers to the more elementary use of tangible physical (or "external") force, such as that produced by muscles. Neijin (Traditional Chinese:內勁) or Neigong (Traditional Chinese: 內功), in contrast, refer to "internal" forces produced via advanced mental control over psychic energy (the qi).

The degree of Li force one can employ in kung fu depends on several variables such as resilience of muscles, strength of bones, speed and timing of attack and so on. An effective way to enhance the Li force is to exercise one's muscles and bones by applying increasing pressure on them (weight training, gym exercises, etc.).^[2] The stronger one's muscles and bones become, the more powerful and skillful the level of kung fu is.^[3]

On the other hand, the level of the Neijin force depends on the extent one can exercise over one's will power to release an inner qi energy. Within the framework of Chinese martial arts, every person is believed to possess the inborn energy of qi. Martial artists can harness the force of qi so that it is strong enough to be applied in combat. When qi is being directed by one's will, it is called Neijin.^[4]

The Li force is observable when it is employed. Unlike the Li force, Neijin is said to be invisible. Both Li and Neijin need the "pivot point", but Neijin is intelligent enough to deliver contact force near muscle force when able to minimize the resistance arm length of self body's mechanical disadvantage lever. At the point of attack, one must ‘song’ (loosen) himself to change the contact force angle and position for proper lever control, to generate all Neijin energy one possesses and to direct this energy stream through one's contact point with an opponent.^[5] The contact point only represents the gateway to conduct Neijin energy at the point of attack.^[6]

The kung fu component of Li force is limited by one's physical condition. When a person passes his/her prime age, one's kung fu ability will pass the optimum level, too. The degree of kung fu will decline when muscles and bones are not as strong as they used to be. On the other hand, the kung fu aspect of Neijin is said to continually grow as long as one lives and always practices in lever control.^[7]

Net force and lever control

Self controllable physical elements in martial art include: mass, muscle strength, and lever

Neijin needs net force control to maximize the force constraint based on one's muscle strength training and lever control to maximize the muscle force delivery efficiency. The following joint safety is also important for Neijin:

1. For extension, reserve flexion angle and prevent overextension^[8][9]

2. For active contact actions, keep parallel relation between shoulder/hip torque and elbow/knee pivot and avoid perpendicular relation between them^[10]

Net force control

Whatever one is going to strike, block or dodge(away from opponent or perpendicular to the distance between one and opponent),^[11] the following force sources for temporary self body mass or momentum increase can resist, stop the effect of contact force applied by opponent and even control self body's net force actively:

• self weight^[12][13][14]

• ground friction^{[15][16][17][18][19][20]}

• normal reaction forces from standing ground^[21][22] and holding wall,^[23][24] handrail,^[25][26] and opponent body^{[27][28][29][30][31]}

Lever control

When able to maintain the best mechanical disadvantage lever with the following two conditions by minimizing resistance arm in terms of major pivot joints(center of gravity, shoulder and hip, elbow and knee), the contact force can be near the muscle force:

1. Minimize the direction difference between net force control, contact force and major pivot joints movements

2. Minimize the perpendicular distance between the paths of net force control, contact force and major pivot joints movements

The worst mechanical disadvantage lever, which violates the two conditions, should be avoided in self body. With proper limb catch angle and timing,^[32][33] keeping the best mechanical disadvantage lever to control opponent's worst mechanical disadvantage lever will take the best mechanical advantage lever.^{[34][35][36][37][38]} Therefore, one's longer arm span (wingspan or reach) or leg length allows longer striking distance, but also allows opponent to take longer effort arm for destabilizing in stiking or controlling in grappling if the one's corresponding muscles are not strong enough to resist.

Sports example

The Neijin physical body structures with best self body mechanical disadvantage lever can be seen in following sports examples:

• Hands and legs in series(net force control and contact force are near parallel to spine)^{[39][40][41][42][43][44][45]}

• Hands in series(net force control and contact force are near parallel to shoulders distance)^[46][47]

• Hands and legs in parallel^{[48][49][50][51]}

• Hands in parallel^[52][53][54]

• Legs in parallel^[55][56]

When using a stick-like tool with self body best mechanical disadvantage lever, putting one end of the stick to a gap can get a fulcrum from the gap and take a temporary mechanical advantage lever which can amplify the Neijin force.^[57]

Training concepts

The key to unlock and nurture Neijin is said to be the practice of ‘song’ (Traditional Chinese: 鬆 ). The term ‘song’ can function as a verb which means to keep one's mind and body loose resilient and expanding like the consistency of cotton or clouds or relaxed yet concentrated like the sharp alertness of cats immediately before attack.^[58] The term can also be used as an adjective which has the same meaning as described above. The greater the extent one can achieve ‘song’ and minimize the use of Li, the greater the release of Neijin force.^[59][60]

Neijin trainees are often reminded to refrain from using the Li force, because the energy of Neijin will be locked and blocked whenever the Li force is applied. So, Neijin and Li are said to be mutually exclusive.^[61]

The Taijiquan master Yang Chengfu used the concept of ‘song’ as a benchmark in his daily teaching. It was his daily routine to keep reminding his disciples to ‘song’ thoroughly more than 10 times when he inspected them.^[62]

See also

• Neijia