Tucking the Tailbone in T’ai-Chi-Form Practice: Good or Bad?

by Robert Chuckrow, Ph.D.

Some Yoga and T’ai-Chi teachers erroneously have students tuck their tailbones to reduce an excessive curvature of the lumbar spine. Doing so fails to get to the root of the problem, adds an additional problem, and starts a “pelvis-spine war.” A look at a skeltal drawing will reveal that the spine and pelvis are interconnected by the sacroiliac joint and have a degree of independent movement. One problem is that many who try to tuck their tailbones actually manage do so by tilting their pelvis, thereby forcing their tailbones to tilt and lumbar spines to straighten (not a good idea). Others force their tailbones to tilt without moving their pelvises (also not a good idea).

Han Xiong Ba Bei

In T’ai Chi, there is a saying, “han xiong ba bei,” which means hollow the front and expand the back. The back referred to is mainly the lower back, which for most people, is excessively curved inward.

Han Xiong Ba Bei Characters

The characters for han xiong ba bei.

Han Xiong Ba Bei Pronunciation

The pinyin pronunciation for han xiong ba bei.

Causes of Excessive Lower-Back Curvature

Many people—especially women—experience lower-back problems. Such problems can result from heels on shoes, improper lifting of heavy objects, overweight, and copying adults with poor posture when very young. A detrimental, excessive curvature of the lower back often originates from heels on shoes, which unnaturally lift the backs of the legs, causing the body to tilt forward (see Figure below). To compensate, the top of the body must lean backward, thus harmfully accentuating the lumbar curve of the spine (“swayback”).

Effect of Heels on Posture

A Demonstration of the harmful postural effect of heels on shoes. Note how the pelvis is thrust forward, causing the inward curve of the lower back to be unnaturally exaggerated.

An excessive lumbar curve weakens the ability of the body to exert forward force. It also throws off the posture of the entire spine and causes other problems including lower-back pain. My book, Tai Chi Dynamics, has a section on han xiong ba bei and how muscular expansion plays a role. I also explain by means of force diagrams how an excessive lumbar curve makes the body weak, how using contraction makes the body weak, but how using muscular expansion makes the body strong.

Unfortunately, han siong ba bei is sometimes misinterpreted by T’ai-Chi practitioners and teachers to mean “tuck the tailbone forward,” which indirectly forces the lumbar curve to be reduced. However, reducing that curve by tucking, which pits one part of the body against another, goes against the T’ai Chi principles and is a harmful, unnatural way of treating the body. There is a big difference between (a) achieving han siong ba bei by sending neural messages to extend the muscles that control the lumbar curve and (b) forcing the lumbar spine into place by means of contracting muscles that are in a different part of the body.

An Exercise for Reeducating Your Use of Your Lower Back

You will need a pillow and a small towel. The height of the pillow should be such that when you lie on your back with your head on the pillow, your cervical spine is in its optimal alignment. Roll up the towel. Lie on the floor with the towel under your lower back and your head on the pillow. Start by surrendering to gravity, relaxing every part of your body. Relaxation is essential to achieving an awareness of what parts are involved in activating a movement. Next, gently press your lower back into the towel by using the muscles around the part of the spine touching the towel. Only a tiny amount of movement is necessary. There may be a tendency to use other parts such as your abdomen, ribs, pelvis, legs, etc. However, the goal is to use only the muscles that are involved, namely those around that part of the spine.

Habitually accentuating the curve in your lower back involves a lack of awareness that you are overusing the associated muscles, so the object is to gain this awareness. After a while, try lifting your lower back away from the towel slightly. Then try arching your spine to one side and then the other slightly.

When you feel that you want to stop, roll over onto one side, and using your arms, come up sideways to a sitting position. This way of rising off the floor minimizes tensing the muscles around the spine and reverting to your habitual way of using those muscles. Then slowly come up to standing, and feel your whole body. It is also useful to recreate that heavy feeling you get after taking a hot bath.

It may take some time to learn how to move your lumbar spine independently, but once you have learned to do so, you will become aware of habitual tension in that region and have the tools to release it.

How the T’ai-Chi Principles and Philosophy Apply

The most basic T’ai-Chi principle is that of the separation of yin and yang. The front of the body is yin, the back is yang. The yin elements that apply are inactive, supportive, and concave. The yang elements that apply are active, expanded, and convex. Tucking the tailbone requires contracting the front, which reverses yin and yang; that is, the front becomes active (yang), and the back becomes inactive (yin). Moreover, the T’ai-Chi principles teach us not to force anything and to have every joint in its most neutral alignment. For example, the T’ai-Chi Classics say, “In any action, the whole body must be made as light and free-moving as possible, so light that the addition of a feather will be felt for its weight, and so free-moving that a fly cannot alight on it without setting it in motion.” Fixating the tailbone, pelvis, and thigh joints in an off-centered alignment is antithetical to the basic principles of T’ai Chi.

The correct way to work on a person’s excessive curvature of the spine is through exercises that reveal to the person that he/she is using a lot of force to sustain the excessive curvature. Once that habitual force is released, the spine gradually assumes its natural shape.

I have successfully worked with a number of students on this issue over the years. The critical stage is to learn to extend the muscles of the lower back (read about muscular extension). My experience is that most people require quite a bit of instruction and practice in this regard.

Whereas it is important to be able to attain a state of han xiong ba bei when it is needed for exerting a large forward force, doing the form in such a continued state of extension has no purpose because you are not exerting a large force on another person. The natural lumbar curve is appropriate for standing and locomoting, as occurs in the movements of the T’ai-Chi form. Holding the body in a state of unnecessary tension is a fixation, which is also against the T’ai-Chi principles. Instead, in doing the T’ai-Chi form, it is only necessary to allow the pelvis to float and the lumbar curve and tailbone to release naturally. Of course, those practitioners who are unable to achieve han xiong ba bei without tucking will need to retrain their thinking and learn to attain the natural, released shape of their lumbar spines.

Here is a link pertaining to tailbone-tucking in which “tucking” is done by pulling the pelvis forward by contracting abdominal muscles rather than by extending the lower-back muscles! https://www.youtube.com/watch?v=H31_SUtj4o0.

©Copyright 2011 by Robert Chuckrow

More Articles on T’ai Chi

Tai Chi Dynamics Book

Home Page