I attended a convention a long time ago, it might have been an aerobics convention somewhere in Canada.
One of the tools on display was a triangular array of 6 foot (190cm) high pillars that you stood in the middle of. Each pillar had pads that were hit sensitive and that lit up. If one (or more) lit up, the idea was to tap the pad quickly. A pad could light up on any of the three columns and for me I found that after each strike I was better able to perceive (and hit) the next pad if I returned to the center each time.
And so one way to think of "center" or being centered is that you are ready for anything.
In the case of the three pillars, by being in the center of all three, and by being aware of all three (not just focused on any one or two) I would see a pad light up and ideally be able to strike it with ease from my centered position.
Because the arrangement was triangular, orientation mattered also. Rather than having my back to any one column I had my back facing the midpoint between two columns so that I could easily see the back two columns using peripheral vision and a slight turn of the head.
So being centered isn't just about physical positioning for ease of hitting, but also for ease of sensing.
My dad taught me the same idea with respect to driving. He drilled into me to always position the car with respect to other cars so that I had room to maneuver but also so that I could more easily see what is happening around me. With space around me I could not only see I could also respond in such a way to stay safe.
Note that the two situations are slightly different. In one I'm trying to hit a target that lights up, in the other I'm trying to not hit other cars. But in both situations the same basic principles matter.
In order to do what I want to do
I need to be able to:
A recent goal has been to do both Tai Ji and yoga without my hip popping all of the time.
A hip pop, if you haven't experienced it, is like something within the hip joint is suddenly adjusting, like a tendon or ligament suddenly jumps from one position to the other, like plucking a guitar string. At least that's what it feels like.
Part of it is the type of movements that I do and teach. I notice it in my students also after doing particular movements.
Movements that cause hip popping tend to be from positions where the hips are bearing weight and there is a transition from one position to another. It may be particular prevalent at the limits of hip joint mobility, say coming out of a forward bent, or turning the pelvis to maximum either to the left or right.
Moving slowly I can often feel when a pop is about to happen. There's a slight increase in tension. Not an uncomfortable amount, just indicative that popping is about to occur.
Having spotted the indicators, I can then sometimes adjust either the thigh or pelvis to relieve that tension before popping occurs.
With yoga and tai ji both, preventing hip popping may also be a matter of creating additional tension in the right places. Positioning of the feet, heels, ankles and knees as well as tension across these joints can have an affect on tension and positioning of the hip joint. So as well as focusing on the hip joint I'm also focused on these parts of the body also.
With tai ji, all of the above applies, but there is an additional factor that I've also found extremely helpful of late.
And it goes back to the idea of center.
How do you center a joint? Another word for this is centration. How do you centrate a joint?
To center (or centrate) the hip joint, some suggest that maximum contact between ball and socket of the hip joint is important.
My understanding is that the ball and socket of the hip joint don't actually touch. Instead, in the ideal, space is maintained between the two by a combination of tension and pressure. The tension occurs in the joint capsule envelope and is in part due to muscular activation. The pressure comes from the fluid within the joint capsule envelope and is dependent on tension within the joint capsule envelope.
The tension is important because it is generated by muscle activation and because it is something that can be sensed.
With a hip joint bearing weight, the weight of the body could press down on a joint potentially squeezing fluid from out between butting joint surfaces allowing bones to touch. To prevent this, muscle activity could be used to add tension to the joint capsule to resist fluid being squeezed out from between the two bones.
When moving, with the hip weighted, a movement might take the hip out of a range where one set of muscles is activated and another takes over to keep maintain joint capsule tension and thus fluid pressure.
Or it may be that some connective tissue structure has to keep active to keep the joint safe and so undergoes a dramatic (and twanging) change as the body shifts.
Another scenario is shifting weight from one foot to another, something that frequently occurs in Tai ji. Here the hip to consider is the hip that is about to bear weight. Is it positioned so that it is as ready as possible to take that weight shift?
Going back to the three columns game, position and orientation affected my ability to see all three columns at once. With driving, positioning relative to other cars affected how much I was able to see around me.
Positioning and orientation affects body awareness also.
An adjustment of the pelvis relative to the femur or vice versa can affect the feel of a hip whether or not it is bearing weight. And now when I do tai ji and am getting ready to move the pelvis and/or shift weight from one foot to another, I pay attention to both the weight bearing hip and the non weight-bearing hip. Both are important, and if I adjust them and position them correctly, I can make transitions without either hip suddenly popping.
Note that in this case the focus is on adjusting positioning to affect tension and thus "feel".
One thing to remember when working on improving body awareness and body control is that muscle tension and tension in general affects the position of the body but the position of the body affects muscle tension.
And this is true too in the three columns game. With optimal positioning, being centered, I could not only easily sense what was happening, I could easily respond. And with driving a car, the same thing, with space around me I could sense what is happening around me and have room to respond.
You could think of being centered as the equivalent of opening or closing a door.
With a door open things can come in (sensory information) and things can go out (response). With the door closed, neither can occur.
One thing that has come from this methodology is that I deliberately limit some movements. I may not shift weight completely to one foot with the hip internally rotated. Or if I do then it will require some adjustment of pelvic tilt both in the front to back direction and the left to right direction (in this case, left to right means whether one hip is higher or lower than the other).
This requires awareness. I have to feel my pelvis and femur in order to know how to limit movement effectively.
In terms of movement quality, the most important thing when learning to avoid hip popping is to move slowly and smoothly. Only by moving slowly and slowly can you learn to feel when the hip is about to pop and either stop to readjust or adjust on the fly. And if you haven't got the necessary awareness then moving slowly and smoothly can help you learn it.
In terms of feeling and controlling the parts of the body, the only way I know how to do it effectively is to focus on little bits at a time.
And that is basically what I teach in most of my classes, feeling and controlling the parts of the body so that you can get better at operating it.