Quarter body move difficult with no Yin/Yang separation

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Quarter body move "hard" with no Yin/Yang separation

There is harmony to be found in the quest to foster "internal strength" (neijin) in the body.  One has to first understand the yin-yang principles that underpin "internal strength" and become proficient with them. Neijin manifests in the muscles and skeleton of the human body but depends more on the harmonious motion of the numerous segments of the body than the size of muscles. The "harmony" comes from an internal (musculoskeletal) ability balance.  This balancing in this video, for instance, comes with the segmentation and subsequent alignment along the spinal column.  In this instance, however, it is located primarily in the upper quadrant or "quarter body".  The sensation of movement although directed by the mind in the upper quadrant does reach as far down as the gluteus maximus.  The "harmonious" movement consists of one part of the body moving while the other part is still.  This is called the delineation of Yin and Yang, stillness and movement.  The better the delineation,  the better the "energy channel" for the cultivation of inner strength.  The better the "energy channel" the better the growth of Qi.  Qi then is dependent on this "ideal" for motion, specifically, that which works in conjunction with the principles of Yin and Yang.