When I began Wujifa stance practice, I was told to "drop". I thought "tuck" meant "drop" so I tucked and I was told to not tuck but to drop. I really didn't know what my instructor wanted. What was the difference between drop and tuck? Was drop akin to un-tuck? Was drop just a little less arch? What was the difference in the feeling of arch, drop and tuck?
I struggled with this puzzle for years, never being able to really kinesthetically feel the difference. Only in recent months have I been able to distinguish these different feelings and to a lesser degree, the feeling of the intention to arch, drop and tuck.
The following videos explain the mechanics of pelvic positioning through the frame of "Muscle Balancing". (I never heard of muscle balancing before writing this article. As a layman, I like these explanations and I think they fit here.)
"What are Muscle Imbalances?" by Jeff Gordan Parker - Muscle Balance Training
"What is a Muscle Imbalance?" by Sam Visnic - Back Pain Relief Blog
"The Psoas Muscle and Lower Back Pain" by Sam Visnic - Back Pain Relief Blog
Even though these videos discuss muscle imbalance for the purpose of relieving back pain, the discussion seems relevant to understanding the structural, mechanical aspects of Zhan Zhuang particularly in regards to the muscular forces acting on the pelvis which helps explain why this section of the body, the tan-tian, is so challenging to calibrate.
What is interesting to me is that I can now notice that arch and tuck each require a bit of muscular force. And since one of the principles of Zhan Zhuang is to relax, it doesn't make sense to use one muscular force (tuck) to counter another muscular force (arch) when the goal is to relax with balance and structure.
If one understands relax and structure, this leads to an understanding of balance. If one understands balance and relax, it leads to an understanding of structure. Understanding structure and balance leads to an understanding of relax. Remember, relax is not limp. Structure is not rigid. Balance is not polarity.Noticing that arch and tuck each require muscular force, I now know that tuck is not relax. Tuck did not lead me to the feeling of drop or sink. Also, I now notice that when I arch, I feel a "pulling up" from my heals and when I "tuck" I feel a pulling up from the front of my thighs. Only inbetween, in drop, do I not feel that "pulling up" feeling but rather an openness, an opportunity to not pull up, to drop.
Going a step further, when I'm practicing stance in class, my instructor will notice ever subtler levels of my residual tuck habit. Where I think and feel like I'm in drop (relaxed between arch and tuck), he will notice that my intention is off the bulls-eye of drop and is slightly into arch or tuck. Sometimes a very slight physical movement is needed to make the correction and sometimes a slight recalibration of my intention to is all that is needed. I cannot yet notice myself where my "intention to" is mis-calibrated.
The below stick figure diagram attempts to illustrate the direction of the intention to tuck, the intention to drop, and the intention to arch (the red arrows). Over time and with practice I've been able to "loosen my hips" without control, to developing some kinesthetic control, calibrating from gross mechanical muscular movements to finer discernment of where the "intention to" is focused; moving from the outer arrows to becoming more perpendicular to the ground.
This is one aspect of my ever changing Zhan Zhuang practice. This is where I am now. Happy practicing everyone!