Your question is important. From the answer everything will eventually come.
Unfortunately a forum is not the best way to answer it. Even the best way – watching you play, showing you how I play, and then hands-on to suggest how to move, so that you can
see the movement,
feel the movement and
hear the sound produced by the movement – may still not lead to the answer.
When you ask:
how do you prevent (i.e. detect early enough) muscle tiredness or really harmful motions, especially when searching for and exploring new ways of moving?
I cannot really answer, because you are the one feeling the tiredness, so only you can detect it.
However I will give you an example that may point you in the right direction and at the same time highlight the difficulties of discussing this through a verbal description.
Consider the following sequence of notes: (Consider the f major scale: F – G - A – Bb – C – D – E – F1 right in the middle of the piano).
Bb – F – Bb – C – D – Bb – D – Eb – F1
What would be the best movement to play this passage at speed with perfect clarity on each note (with the right hand)?
Incidentally this is the first motif in Scarlatti sonata K70. In one of the editions I have, the following fingering is suggested:
Bb – F – Bb – C – D – Bb – D – Eb – F1
3 – 1 – 2 – 3 – 4 – 2 –
3 - 4– 5
I found this fingering extremely awkward, in particular the highlighted fingers. Negotiating the Eb with a fourth finger was only possible at the expense of the sound: using this fingering resulted in a very irregular and uneven passage at speed, and often in wrong notes. Now you have two very distinct possibilities here:
1. My technique was not good enough, and that was the reason why I could not negotiate the passage with that fingering. If that is the case, I must develop the technique by practising the passage with this fingering. Given the size of the passage and the fact that the really awkward part refers to only two notes, 5 – 10 minutes practice should be more than enough to either develop the technique and master the passage, or experience such an improvement in regards to the first trials that I would be reassured that indeed the fingering was appropriate and my technique was lacking. However if after 5 – 10 minutes I could not master the passage to my content or see any clear and definite improvement, then that fingering and the technique it implied was not for me (it may work fine for someone else though).
2. The fingering was inappropriate for my physicality, and I would have to find and alternative fingering together with the implied movements. In this particular case, this is the fingering I come up with after some experimentation:
Bb – F – Bb – C – D – Bb – D – Eb – F1
3 – 1 – 2 – 3 – 4 – 2 –
4 - 3 – 5
A tiny difference is it not? And yet almost immediately (in about 2 seconds) the passage came absolutely clean and without any effort whatsoever. I knew immediately that I was onto something good. However it still took 5 – 10 minutes to work out the peculiar movement of arm/forearm/hand/fingers that this fingering required. There was a slant of the hand without which it would not work. There was a “walking” movement of the fingers without which the fingering likewise would not work.
I suggest at this point that you go to the piano and try this motif with both fingerings and decide if you can make sense of what I am saying. This is ridiculously easy to demonstrate and guide someone’s hand so that they experience what I am describing. Saying it in words however can lead to all sorts of misunderstandings.
How did I come up with such a fingering? There is the experience of many years investigating this sort of thing both in myself and on my students. There is the fact (which I happen to know) that during the Baroque passing the 3rd over the 4th was the rule rather than the exception. There is my philosophy that movement never comes from the fingers: the fingers are at the end of the movement. And I believe in changing what you are doing until you get the result you want.
Most importantly, fingering for fast passages like this one cannot be decided with slow playing. The first fingering will work fine as long as you play slowly. It will fall apart the moment you increase modestly the speed. Of course once you figure out the fingering/movement required at speed it will be all right – and beneficial – to practise it in
slow motion.
So now for the question of time. It should not take more than 5 – 10 minutes to decide on any movement covering a passage of this small size. If after 5-10 minutes, the passage is not mastered or substantial improvement is not apparent, you must change your technique.
On the other hand, it may take several weeks of experimentation to find that perfect movement that will make the performance of the passage not only perfect, but
easy. But these several weeks will not be devoted to a single fingering/technique/movement, but to a myriad of different options each taking 5 –10 minutes to be accepted or discarded.
In the beginning it will take forever and you will be discouraged with such an approach. But soon, as you get to know your body, its limitations and the techniques to which it respond well, the process accelerates. To the point where by just looking at a score you will know instantly how to best move to play it.
It is also important that you do your investigating with hands separate, since hand memory is acquired with hands together, and once an inappropriate technique (for you – for the passage) is ingrained in hand memory it will be there pretty much forever. So only start hands together practice after you have figured out the technique.
Now with these principles and ideas in mind, approach trills. Trills have different problems depending on the piece/style/period. It is really too long a subject. But I suspect that you are talking about long trills whose main problem is the stamina to get them going. There were several threads on these with plenty of ideas for you to experiment with. I will just remind you of this: The muscles used in piano playing are small and numerous. Mostly they are located in the forearms (get an anatomy book and investigate). Muscle that is not used atrophies. Muscle takes 3 – 6 months to grow and will only grow if exercised regularly (every 36 hours). If you have not done long trills before, you will not have the necessary muscles to do them. You will need to grow them. Think “the Bride” (Kill Bill). She was in a coma. When she awoke, she knew what to do, but she did not have the muscles to do it. But at least she knew what to do. Now imagine if besides not having the muscles she did not have a clue on how to use them.
I don’t know if you know pianist Jack Gibbons (you may have heard of him). Some years ago, he had a horrific car accident and his left arm was pretty much destroyed. It was rebuilt (he has so much metal I his bones that he must take copies of his X-rays with him if he wants to board a plane). Yet he was able to rebuild all his technique from scratch in a bit more than a year, and now he is back concertizing. Why can’t anyone acquire all the technique in one year, like he did? Simple: because he knew exactly what to do. (And acquiring that knowledge took him many years).
I hope this helps.
Best wishes,
Bernhard.
Topic: exploring new movemnt - avoid fatigue