Remember that "exercise" I wrote about cpl of years back for the thumb?
I think that the aim of that exercise was to get the thumb in a Cziffra/Rubinstein position that is being able to resist the key with the second joint of the thumb a sort of thumb knuckle".
I would be very interested to see your exercise to develop that joint. I have some of my own which I will share later on.
It is actually no fantasy to give functional significance to that joint. It turns out that we have more than one arch in the hand as we can see here: (you can click on the names of the arches to see how they are positioned in the hand). The one we are talking about (the thumb's middle joint included) is the so-called "distal transverse arch", sometimes called "metacarpal arch" that runs from the thumb's middle joint over the metacarpals to the pinky. All those arches should be able to bear a considerable work load as a whole and in their separate elements in a healthy virtuoso technique. A weakly developed distal transverse arch will inevitably lead to pain/lack of comfort in the pinky area in certain "athletic" repertoire, even though the longitudinal arch (the one most of the posts on this forum seem to be focused on) may be well developed. Training the thumb's middle joint properly somehow unites the upper half of the thumb with the surface of the hand in octave and chord technique (the hand becomes "bigger" so to speak), while the thumb is still independent enough with the other part to fulfill other functions in finger work etc.
Paul
I just can't quite follow the mechanical basis for impact avoidance here. I can only see two really obvious ways to avoid impact. One is to let the joints bend out during landing, just like the way people's knees bend when landing a jump. This slows down the rate of energy transfer (like a cricketer pulling his hand back while catching a ball). However unlike when landing the body (where the mass is necessarily at a speed outside of our control and need merely have the energy dissipated more gradually) we need to pass on speed through the equivalent to the feet. It you have give in your pianistic legs, you need far more momentum to be sent at the keyboard to get the same acceleration. You also have to pull back not to collapse into a cluster (the knees are much better at absorbing energy). I don't regard anything based around give as being in any way functional, as it destroys the acceleration of the key and demands more brute force if we wish to play really loud. If it works its not so much the illusion of give, as a state that is ready for useful movement.
The only alternative I can see to this flawed version is when momentum is redirected- via springing out of a landing that is not entirely vertical. It pushes momentum away from the point of landing and thus prevents the sense of crushing down. I just can't see any other basis to dissipate energy without impact besides these two. The energy cannot be destroyed, so you can either push it away in another direction, or you can relax to spread out the moment of impact during a longer time. I know I can bounce off safely with either thumb (including when at full length). I can see a role of lengthening (to stabilise without stiffness) but I just can't follow what else there is for it to offer. General muscle tonus doesn't really explain energy absorption, except when in the context of slowing down a collapse. Other than that (as anything collapse based is functionally ineffective) seems to depend either on fixing or trying to move in direct opposition to the collapsing force.
By the way, strictly speaking, even grasping would be a very high impact landing except when done just right. Squeezing inwards would cause an immense sense of collision when falling straight down. It's only when lightening up (and giving a slight forward impulse, to create an indirect line of landing) that the grasp helps the momentum to be bounce harmlessly up and away. I've learned how to do this now, but it's definitely tougher within a concept of falling rather than whipping or flicking the hand in an active rather than passive fashion. Gravity cannot be removed from the line of descent but there are some very important extras.
I remembered that I made this clip ages ago to illustrate that issue. At the start I deliberately use give in the hand. Although good for landing a jump, you can see how it kills all the sound. Afterwards I showed the simple energy transfer associated with with expanding. I'm sure that rubinstein is doing at least a little of that, rather than either collapsing slightly or stiffening against it. I sometimes do it with a more significant lengthening of the thumb during sound, but it honestly works fine if the thumb has found full length already, as the long as the direction of movement is up and not straight down.
https://youtu.be/30a9N3oDBd0
I'm sure that rubinstein is doing at least a little of that, rather than either collapsing slightly or stiffening against it.
Rubinstein is not collapsing and he is not stiffening. He must indeed be expanding his hand at least a little bit, but that element is not visible in the clip since we have got the wrong angle.
P.S.: To get Rubinstein's sound effect, though, you really need to use the whole arm, Andrew! Slightly diagonally forward into the key is best for tone control. In your clip, you come straight down with too small a playing unit. Afraid of hurting either your piano or your playing apparatus, huh? (just kidding)
Paul
Don't worry, I'm not afraid to go all out sometimes. To be honest rubinstein's sound doesn't do it for me here though. It's interesting that he's in such a hurry to get on to the second octave. I don't think the whole arm descent gives a good resonance that lets the sound ring effectively, which probably links to that sense of haste. I prefer a more resonant and lasting organ like quality here- like the big sound nyiregyhazi often makes while still playing nowhere even close to his maximum volume. I sometimes start directly from the key, but sometimes I'll add just a small hand drop to the hand action. However, in such an exposed texture I don't really like such a large arm drop. It doesn't seem to give the same sense of ringing out. I try to make a big sound but with a sense of slight restraint, rather than by going all out towards my max. For me, the whole arm impulse only makes it more difficult to make a lasting rather than aggressive tone. Although not as as brash as someone like kissin tends to be, it's not a result that I find satisfying compared to my ideal for the passage.
