LaoDan wrote:The importance is for avoiding the “butting cow” (顶牛 ding niu) error (using primarily horizontal force) that is often witnessed especially in things like push-hands. The rounded groin instead produces a more vertical force into the legs, like an architectural arch that directs forces down into the support columns (the lower legs) rather than outwards. Vertical force aligns with gravity and favors what we naturally practice every time we stand up.
I see your planned article is in its early stages
but I’ve never heard the descriptions you use to describe horizontal force in Taiji.
I'm not saying you're wrong, however,
In Yang Style Vertical and Horizontal force is used & also combined.
Actually, there are many examples of using horizontal force in Yang Style writings.
For instance, Chen Weiming talks about using horizontal motion in applying Ward-off.
LaoDan wrote:...Here is a quote from my preliminary incomplete draft:
We habitually respond to forces in front of us by pushing back (resisting), or by pulling to our rear. This is, in effect, responding horizontally. We have taught ourselves from childhood to use our weight against resistant objects that we wish to move, which is reflected in the sayings “put your back into it” or “throwing your weight around.” If we push or pull against something that suddenly gives way, we can lose our balance and may fall down. This is the result of acting on forces horizontally. This horizontal approach can be exploited because of the loss of stability when the pressure suddenly changes, and Taijiquan warns against leaning against the opponent.
On the topic of losing stability, in his book
The Essence and Applications of Taijiquan,
Yang Chengfu talks about using Horizontally energy to destabilize the opponent.
Chengfu wrote:At the same time, take the left hand and lift it up in front of the chest, with the heart of the palm facing in. The elbow drops slightly. Then, using my wrist to attach to the opponents arm between the elbow and wrist, I use horizontal energy (heng jin) to ward off forward and upwardly (peng qu). One must not show a stiff and wooden appearance; then, when the opponents strength has already been shifted by me, his position becomes unstable of its own accord.
Essence & Applications
It's interesting that you view horizontal force as "Strength against strength."
LaoDan wrote:To me it is about favoring vertical forces as opposed to horizontal ones like a butting cow. Not that a butting cow cannot produce powerful force, but that is just training strength against strength rather than optimizing structure (i.e., stacking the structure vertically with gravity). I think that we train to act differently than we act instinctively, and we want to maximize the springs through our legs rather than bracing (and tensing) to act horizontally.
In Yang Style it's opposite;
Horizontal motions are used to neutralize & Stick.
Anyway, just a few quick thoughts.
Don't know if any of this is helpful for your planned article.