The Principle of Forward and Backward Movement in Tai Chi (太極前進後退的動力原理)

The Principle of Forward and Backward Movement in Tai Chi (太極前進後退的動力原理)

In Tai Chi, whether advancing (前進), retreating (後退), or turning left and right (左顧右盼), the source of power is not muscular force or momentum but the rebound of gravity through the earth, activated through relaxation and grounding—this is known as "鬆沉後地" (sōng chén hòu dì), meaning "relax, sink, and connect with the ground."

1. Relaxing the Knees, Letting Qi Flow Downward (鬆膝，氣下流)

The movement begins by relaxing the knees (鬆開膝蓋 sōng kāi xī gài) so that the qi (氣)—the vital energy—can flow from the kua (胯, hips/groin) down into the soles of the feet (腳底). But importantly, it does not stop there. The qi continues to flow into the ground, forming an elastic connection with the earth, which provides the reactive force (反作用力) that propels the body forward or backward.

This process is not imagined but physically experienced as a subtle pressure through the feet and legs, known in classics as:

「氣由脊發，根於腳，行於腿，主宰於腰，形於手指。」

"Qi issues from the spine, roots in the feet, travels through the legs, is directed by the waist, and expresses in the fingers."

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2. Advancing and Retreating Use the Same Ground Pathway (進退一如，根在腳)

Whether moving forward or backward, the root (根 gēn) must remain in the feet. The body does not push forward nor does it pull backward, but rather the kua (胯) seeks the heel (胯找腳根 kuà zhǎo jiǎo gēn). The force from the ground moves up through the relaxed and aligned structure.

You don’t move by “sending the body forward,” but by receiving the ground force through the rear leg and letting it carry the body forward, like riding a wave from the earth.

「身隨步進，力由地起。」

"The body follows the step, power arises from the ground."

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3. Turning Left and Right — Spiral Rooting (左右旋轉，螺旋於腳底)

When turning or shifting direction—左顧右盼 (turning left and right)—the driving force comes not from rotating the waist independently, but from a spiraling action in the feet, especially the soles (腳底螺旋 jiǎo dǐ luó xuán). This spiral engages the fascia and connective tissues all the way up through the legs and into the kua, setting the whole body in coordinated rotation.

Instead of “turning the waist” (which could isolate and break the whole-body connection), we relax the waist and sink the kua (鬆腰落胯 sōng yāo luò kuà), allowing rotation to arise naturally from the ground path, with the two kua suspended in balanced flow.

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4. The Internal Sensation — Flowing Water Between the Kua (流水兩胯間)

When done correctly, one may feel as if there is a gentle stream flowing between the kua—a sensation of continuous energy connection and dynamic balance. This is poetically described as:

「流水兩胯間，意念在心田。」

"Flowing water between the hips, intent resides in the field of the heart."

This means the dantian (丹田) and heart-mind (心意) remain calm and centered, while the kua dynamically adjust, maintaining neutrality and rootedness, allowing the qi to cycle effortlessly.

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5. Conclusion: Stability in Stillness and Movement (動中有靜，靜中有根)

This approach requires no brute force, only deep relaxation (鬆), accurate alignment, and attentiveness to ground connection. Movement becomes natural, internally driven, and energetically alive.

The key is:

• Do not pull the body forward or backward. Let the kua find the heel (胯找腳根).

• Do not twist the waist independently. Instead, sink the kua and spiral from the feet.

• Maintain internal listening. Let the qi flow to and from the ground, never stuck at the feet.