In a number of my previous posts, I have emphasised the importance and the role of multi-directional forces. In this short post, I try to give a supplementary explanation, which is kept simple and hopefully can help practice.
To simplify for the sake of discussion, let’s regard that whenever there is a joint, there is always a corresponding joint socket containing it, although such “socket” may vary a lot anatomically. (You can view it as in the mind world, not in the physical world.)
The characteristics of a joint harnessed by your mind can be described as follows. It behaves like a self-powered motor. It doesn’t rely on neighbouring entities (muscles, tissues and alike) to switch it on, but directly started by your mind. And it spins from its own centre to bring about rotations, i.e. it is not turned at the periphery, though around the centre, to rotate.
A joint (joint T) is housed in a joint socket (socket T). While joint T spins (on its own) to rotate the bone attached to it, socket T has its own movement separate from joint T. Such movement is caused by the bone constituting socket T – the bone being rotated by the joint (joint S spinning on its own) preceding it. Following the same relationship, joint T spins socket U through the bone connecting them.
Now you can see how multi-directional force is made possible by joint rotating. While joint T spins socket U forward, socket T is being spinned inward by joint S. The inward-moving socket T brings joint T along, together with T’s connecting bone, socket U and joint U, giving them an inward momentum too. Thus any contact with the T’s connecting bone will experience both forward and inward forces simultaneously. For example, the elbow joint (T) spins the wrist socket (U) forward, while the shoulder joint (S) spins the elbow socket (T) inward. A contact with the forearm (the bone connecting the elbow and the wrist) will have to counter both forward (usually head-on) and inward (usually converging) forces at the same time.
You can extend such application.
The wrist joint further spins the bottom finger sockets slightly downward, while the bottom finger joints spin the next finger segment sockets further downward to the floor. And so on. This will result in a strong “curving” momentum causing the contact at the forearm, where various forces of different directions are acting simultaneously, expelled away (when above) or shot obliquely downward to the floor (when underneath).
The implication for practice is: When opening up (by soften-melting) a joint, don’t treat it just as one entity (if this didn’t help), but two – a joint and a socket. While train to spin from a joint, also in parallel train to move the socket simultaneously but separately. This is the basis for achieving multi-directional forces.