Finding the correct hand motions for fast play is part of the exploratory period. It will probably involve some trial and error. Once you've discovered the correct motions, you should only do a few fast repetitions to be sure that these motions indeed work. You are not really practicing these fast motions, only testing them, so only a few repetitions are necessary.
Thanks for your answer
So, I'm supposed to just play a very small piece fast twice or three times
and then switch to slow motion practice?
Do you use this method?
Do you think this may prevent possible injuries you may get from playing fast first?
Also, I wonder: after you've witched from fast to slow motion should you bring the piece up to speed gradually (put always using the same motions you will use at fast speed) or maybe you just repeat the small passage a lot of times at slow motion and then switch again immediately to fast motion
So, when you use slow motion practice do you use gradually increment of speed or just switch from slow to fast?
Then you begin your slow motion practice. Here you do many repetitions in slow motion. You're totally relaxed and in control. However, an amazing thing will begin to happen. As you practice these slow motion movements accurately, eventually your hand will naturally want to go faster.
Yes I've noticed this too
repetition by repetition the hand wnt to go faster as it get aquaninted with the small passages movements and rhythm
But I've noticed this especially when I switch from right hand to left hand
When I play the passage with the left hand I let my hand rest and after few seconds or minutes when I switch again to right hand, the hand wants to go faster, actually, it is able to go faster now
Should I slow it dows in this case or let the hand choose the speed it wants?
I also wondered if you have ever used the alternating fast and slow practice that Chang himself suggests, once or twice slow and once or twice fast and so on till you have the passage at speed
Now, a summary of this wouold be:
You can injury by using the "playing fast first" method if you
1) choose a passage that is too long
2) play the fast exploratory speed first too many times
But you can avoid injuries if you
1) choose a very small passage
2) do very few fast exploratory repetitions before switching to slow motion practice
Is that right ?
I also wonder another thing
If you use this method, do you have ever experinced the problem of having to find the correct hand motion of a small passage by playing it fast first few times before switching to slow motion, but your fingers are somehwat not able to move at such fast speed even if the passage is very small and the
repetition are vey few... you simply can't even do one repetition of the small passage at such a speed
If that happened to you, what did you do in this instance?
Thanks a lot for your precious answer
Daniel