Should I practice Fast or Slow for Technical issues??

[lance132]

I have been confused on how I should practice lately. I am playing some pieces that are technically demanding.
- Beethoven Pathetique
- Chopin Polonaise in A-flat major Heroic
There are some spots in these pieces that are technically challenging for me and my question is - How do I go about practicing these places. Should I practice them slow or fast?
Most people swear on slow practice others say slow practice is a waste of time for fast passages.
I'm confused as to who is right. I just wanna know which one is better and bring more efficient results.

[chopinrabbitthing]

Quite demanding indeed.
Personally I'd go slowly, because it solves any minor problems and makes sure that I'm sure what is going on.

You probably have to try and see for yourself to see which helps better. Maybe it might help to play fast in some sections, or the other way around.

I've never heard anyone say that slow practice is a waste of time. If you can play it really well and confidently slow, you can speed it up however much you need to.

[brogers70]

I don't disagree with Mr. Rabbit. I'd also suggest practicing very short bits at tempo or even faster, just to see what movements work at that speed. There's rarely a problem if the passage is short enough, even as short as two notes. Then make short, overlapping passages; get each one up to speed separately, and try linking them up.

Slow practice is definitely good, but only if you've already found the motions you will use at the fast tempo. Otherwise you ingrain inefficient movements, and when you try to speed them up you hit a wall.

[Bob]

Why not both?

[iansinclair]

As Bob says -- both.  Sort of, at least in my humble (?) opinion.  What you don't want to do is practise at a tempo faster than you can play reasonably accurately, because what happens is either the hard bits get uneven or they are unconsciously slowed down (trust me, I do it myself!)(do as I say, not as I do...).  That said, there is no harm to playing the easier sections right up to tempo.  The harder sections can be worked on more slowly, but I would advise getting into them and out of them by at least two measures at the same tempo on either side, as it were, of the hard section.  Confusing, sorry.  For example -- suppose there is a ten measure bit of the Polonaise which is a real bear.  Work on it at a tempo which you can manage -- but include the two preceding measures and the two following measures at the same time (total of 14 measures, in this example).

In fact, as a general rule, I would never practise just a hard bit by itself.  I would always lead into it and continue on out of it, at least to encompass the entire phrase.

[gvans]

Right. Ian and Bob are correct. Do both, but don't play so fast when you play fast that you muck things up. Fingering at slow tempo may not work at a brisk tempo. Also, try to play REALLY slow, glacially slow, and perfectly. That often proves to be the hardest tempo of all.

Mixing up practice tempos is best, it helps keep one interested and focused.
Mindless repetition at the same tempo--sonata so good. Capisce?

[nyiregyhazi]

As Bob says -- both.  Sort of, at least in my humble (?) opinion.  What you don't want to do is practise at a tempo faster than you can play reasonably accurately, because what happens is either the hard bits get uneven or they are unconsciously slowed down (trust me, I do it myself!)(do as I say, not as I do...).  That said, there is no harm to playing the easier sections right up to tempo.  The harder sections can be worked on more slowly, but I would advise getting into them and out of them by at least two measures at the same tempo on either side, as it were, of the hard section.  Confusing, sorry.  For example -- suppose there is a ten measure bit of the Polonaise which is a real bear.  Work on it at a tempo which you can manage -- but include the two preceding measures and the two following measures at the same time (total of 14 measures, in this example).

In fact, as a general rule, I would never practise just a hard bit by itself.  I would always lead into it and continue on out of it, at least to encompass the entire phrase.

Why do you specify precisely 2 measures on each side? I don't follow. That's as likely to mean starting in odd places mid-phrase as just practising a hard part- but with vastly less benefit available from doing so (seeing as the extra bars are not only taken out of a phrase but also steal attention from that which is hard, rather than help to focus on it). I don't think a specific formula works here. You just have to use common sense when it comes to fitting things into a context. I disagree that phrases must always be complete but I'd want a clear benefit anytime they are broken and a plan for putting them back together. All too often, having a lead in just distracts the brain from what is necessary to sort an issue that is at first better isolated from other worries. It's fine to take things out of context for maintenance and then put them back into a whole idea straight after.

[pianoplunker]

Right. Ian and Bob are correct. Do both, but don't play so fast when you play fast that you muck things up. Fingering at slow tempo may not work at a brisk tempo. Also, try to play REALLY slow, glacially slow, and perfectly. That often proves to be the hardest tempo of all.

Mixing up practice tempos is best, it helps keep one interested and focused.
Mindless repetition at the same tempo--sonata so good. Capisce?

Good post but you forgot the disclaimer that you English sonata so good. LOL

[awesom_o]

In fact, as a general rule, I would never practise just a hard bit by itself.  I would always lead into it and continue on out of it, at least to encompass the entire phrase.

This is something I agree strongly with!

[nick]

Discovering the best fingering at a pretty fast tempo first.

Once notes are learned well, practice at half speed (50% of goal), no pedal,  as you are training your hand/fingers to play relaxed, no extraneous motions. This builds "relaxed" strength for faster playing.

After some time, try a 3/4 speed run, only occasionally, no pedal! All conditions of the 50 % practice speed observed.

After some time try a 85% run occasionally, making sure no errors, all conditions the same.

After more time, 100% should be obtained.

As you see, the bulk of time is at 50% throughout.

This is what I do with success. Good luck.

Nick

[pytheamateur]

Even a pianist of Rachmaninov's calibre has to practise slow.  There is a well-known anecdote of him practising Chopin's double-thirds etude at a very slow speed.  And he was practising a piece that he had learnt many years ago.

[pianoplunker]

I have been confused on how I should practice lately. I am playing some pieces that are technically demanding.
- Beethoven Pathetique
- Chopin Polonaise in A-flat major Heroic
There are some spots in these pieces that are technically challenging for me and my question is - How do I go about practicing these places. Should I practice them slow or fast?
Most people swear on slow practice others say slow practice is a waste of time for fast passages.
I'm confused as to who is right. I just wanna know which one is better and bring more efficient results.

It is not really one or the other. If you are practicing a fast passage slowly, then once in a while practice  it faster for a sanity check on your fingering. The main thing to avoid is "playing" fast over and over during practice. 

[j_menz]

Practicing slowly only helps if you practice slowly what you will do quickly - fingerings and all movements. If you practice some other way slowly, it won't help. Slow practice ingrains and you need to make sure that what becomes ingrained is what you need to do when you play it fast.

[greglloydmusic]

Hi Lance123,

As a teacher for 27 years, I tell all my students to do everything slowly to start with and build it up in tempo when it feels ready.

I make them speak aloud and hand clap the rhythms in the piece slowly first, then I let them add in the notes and I find they speed up to the required tempo without even knowing it.

If you fully understand the tune tempo shouldn't be a problem.

Hope this helps

Best

Greg

[falala]

There's only one kind of practice that is ever any use - EVER. And that's the kind where you play the right notes.

Practising the wrong notes strengthens in your muscles, mind and nervous system the feeling and memory of play the wrong notes.

Practising the right notes strengthens the feeling of playing the right notes.

So, if you can already play the pieces note perfectly with great reliability, there may be a case for only practising quickly, for musical aspects. But since you described the pieces as "technically demanding for me" I'm guessing you cant - in which case, you need to play them at a speed where can get the notes right (as well as breaking them up into short sections, as mentioned above).

How on Earth anybody can think there can be any OTHER way to practise music one has not technically mastered yet than slowly, is beyond me.

[timothy42b]

Practising the wrong notes strengthens in your muscles, mind and nervous system the feeling and memory of play the wrong notes.

Practising the right notes strengthens the feeling of playing the right notes.

I emphatically disagree.

Whether the notes are right or wrong is almost immaterial.

You can play the right notes with the wrong mechanics, or the wrong notes with the right mechanics. 

Neither gets the desired results, but playing the right notes incorrectly is disastrous. 

That is the reason that slow practice, when uninformed by some work at speed first, teaches bad habits and speed walls.

[gvans]

Timothy speaks the truth. In chamber music, even at an amateur level, you often don't have the luxury to learn a piece perfectly before a rehearsal. In that case, you just have to play at tempo, hit as many important notes as you can, leave out un-important notes, and get on with it. If you insist on waiting until you have the piece learned to perfection, your chamber music partners will have long disappeared to make music with some other pianist.


 

[falala]

I emphatically disagree.

Whether the notes are right or wrong is almost immaterial.

You can play the right notes with the wrong mechanics, or the wrong notes with the right mechanics.  

Neither gets the desired results, but playing the right notes incorrectly is disastrous.

That may be true - I'd need more clarification of what you mean. But it doesn't negate my point.

It may be that for practice to be effective, you need the right notes AND the right mechanics.

But there's no way practice can be effective when it's resulting in the wrong notes. Apart from anything else, the fact of delivering the right notes is one part (only one, mind you) of what defines the "right" mechanics in the first place. Yes, it also has to deliver the right phrasing, articulation etc. But if you have a lovely well-thought-out mechanical approach to a piece that consistently results in you playing the wrong notes, then it is the wrong approach. By definition.

To say that whether the notes are right or wrong is "almost immaterial" is simply ridiculous. Just because a lot ELSE is required as well, doesn't negate the fact that you need to play the right notes. It's one of the basic necessities of playing any instrument.

[falala]

Timothy speaks the truth. In chamber music, even at an amateur level, you often don't have the luxury to learn a piece perfectly before a rehearsal. In that case, you just have to play at tempo, hit as many important notes as you can, leave out un-important notes, and get on with it. If you insist on waiting until you have the piece learned to perfection, your chamber music partners will have long disappeared to make music with some other pianist.

That's surely true, but it's not what the OP was asking about. He was asking about the best way to practise technically demanding pieces of solo repertoire over a period of time. I'm assuming he's looking for a more technically perfectionist approach and result than you're describing. He can correct me if I'm wrong, but that's how his post appears. It doesn't say anything about fudging chamber music parts quickly.

[timothy42b]

Apart from anything else, the fact of delivering the right notes is one part (only one, mind you) of what defines the "right" mechanics in the first place. Yes, it also has to deliver the right phrasing, articulation etc. But if you have a lovely well-thought-out mechanical approach to a piece that consistently results in you playing the wrong notes, then it is the wrong approach. By definition.

By mechanics I mean ergonomically correct motion:  posture, relaxation, rotation, arm weight, angle of forearm and wrist, shoulder position, etc.  Everything physical that contributes to landing on the key with the correct velocity. 

The comment from an earlier post was that playing the right notes strengthens the feeling in muscles, mind, and nervous system of playing correctly.  It does not.  The right notes are EASY compared to doing the rest of the mechanics correctly, at least in the early stages.

Otherwise we wouldn't need a teacher.  A method book and listening for mistakes would be plenty.

[falala]

By mechanics I mean ergonomically correct motion:  posture, relaxation, rotation, arm weight, angle of forearm and wrist, shoulder position, etc.  Everything physical that contributes to landing on the key with the correct velocity. 

The comment from an earlier post was that playing the right notes strengthens the feeling in muscles, mind, and nervous system of playing correctly.

No it wasn't. The comment was:

Practising the right notes strengthens the feeling of playing the right notes.

It only mentions the correct NOTES, not the correct everything else. And it's self-evidently true. When you do something, many many times, your brain creates neural pathways for it that make it more likely you will do the same thing next time. It's true of performing a set of muscular actions resulting in the depressing of a particular sequence of piano keys, just as it is of speaking a language or riding a bicycle. It's basic learning. 

It does not.  The right notes are EASY compared to doing the rest of the mechanics correctly, at least in the early stages.

This bullshit really gets my goat I'm afraid - the idea that playing advanced solo classical piano repertoire with all the notes correct is so easy, and we shouldn't concern ourselves too much with it because it's the other things that are important. Yes, of course the other things are important. But before you even GET to the other things, there's the massive issue of actually playing the piece correctly that you have to address if you want a hope of competing with the thousands of other people that can do it.

So many times have you performed the complete Transcendental Etudes, or Rachmaninov Concerto No. 3? How did the audience respond to your cool "right notes are immaterial" kind of style?

Otherwise we wouldn't need a teacher.  A method book and listening for mistakes would be plenty.

Of course you'd need a teacher because playing the right notes is HARD, you can't just work out how to do it on your own, and you need help from someone who knows how.

[coda_colossale]

Slow practice doesn't help me. Fast practice doesn't help me either. So I prefer not to practice at all.

[nick]

I read the argument and I say all of  Falala's posts are accurate in my experience.
  I will also add that the term "slow practice" can mean different things to different people.
An elite runner training slowly is pretty darn fast! I've seen them.
  After correct notes are learned I am not in favor of Real Slow practice(met 40 as it seems pointless. But the practice must be perfect with NO STRAIN or pushing for speed. My practice speed feels easy, like I could do it all day at that speed. My speed may be different than another's. As an example, I am playing the 3rd move. to Moonlight. I like the speed of 110 right now. I'll try it at 138 once most days and love the sound, but only once if even that.

Nick

[pianoplunker]

Timothy speaks the truth. In chamber music, even at an amateur level, you often don't have the luxury to learn a piece perfectly before a rehearsal. In that case, you just have to play at tempo, hit as many important notes as you can, leave out un-important notes, and get on with it. If you insist on waiting until you have the piece learned to perfection, your chamber music partners will have long disappeared to make music with some other pianist.


 

It is perfectly normal to make mistakes at rehearsal. That is why they call it rehearsal. If you cant get rid of bugaboos by the third rehearsal you may need to reconsider if the music is too advanced for you. Because if you are aiming for a specific date, you need to have the basics down early on

[pianoplunker]

Slow practice doesn't help me. Fast practice doesn't help me either. So I prefer not to practice at all.

That is what I was hoping for, but then I practiced with another human being.....

[dima_76557]

This bullshit really gets my goat I'm afraid - the idea that playing advanced solo classical piano repertoire with all the notes correct is so easy, and we shouldn't concern ourselves too much with it because it's the other things that are important.

You must have misunderstood timothy42b's very wise words. That is not what he was implying. What I perceived him to be saying is the following: By simply practising the notes correctly in whatever tempo without paying attention to the required functional mechanics, one is ultimately bound to fail. It may work for some time for some, but at a certain point, the whole technique starts falling apart, not to speak of the notorious "speed walls" we create for ourselves with such practice.

[timothy42b]

You must have misunderstood timothy42b's very wise words. That is not what he was implying. What I perceived him to be saying is the following: By simply practising the notes correctly in whatever tempo without paying attention to the required functional mechanics, one is ultimately bound to fail.

That is what I intended to convey.  I do apologize for not being clear enough.

[nick]

You must have misunderstood timothy42b's very wise words. That is not what he was implying. What I perceived him to be saying is the following: By simply practising the notes correctly in whatever tempo without paying attention to the required functional mechanics, one is ultimately bound to fail.

I still disagree with this. There is a certain assumption most of us expect when as an adult with some piano training, that certain mechanics are observed, like economy of motion for key depression and fingering. Playing the thumb on consecutive notes in a scale is ridiculous. So with that basic understanding in mind, playing the correct notes in the correct rhythm and tempo will not cause failure. I think that of all the elements in learning a piece of music, correct notes and rhythm would be the most important. One may need to tweak the method, amount of weight on the fingers etc, but the basic cause and effect would be the notes, tempo and rhythm. Even if one started with very raised fingers, the underlying elements of notes rhythm and tempo are still the most important because one can tweak the method through observation. But without the notes and rhythm we don't have a lot to work with.
 

Nick

[dima_76557]

I still disagree with this.

I respect this. However, everybody has a different "ceiling". It is never too late to recognize that something is lacking behind all the correct notes, rhythms and tempi (fast or slow doesn't matter). If one is not so lucky, however, or is too stubborn to "listen" to the tell-tale signs of upcoming disaster (as in my case a couple of years ago, for example), nature will simply block the lot from functioning properly.

Famous pianists like Artur Rubinstein are also known to have revised their technique later in life (some a few times even) because up to a point, they had only been training pieces with all the requirements you indicated without paying special attention to certain elements of movement and choreography.

Besides, from what I understand, retraining is a lucrative business nowadays. Repetitive stress injuries bring misery to more instrumentalists than you can ever imagine.

Here is a description of how musicians can get into trouble, and what can be done to either prevent or cure: https://www.pianomap.com/injuries/index.html

[falala]

That is what I intended to convey.  I do apologize for not being clear enough.

OK. Thanks for the clarification.

I think the misunderstanding was that I never meant to suggest it was enough to "SIMPLY practise the notes correctly". Of course it isn't. All I meant was that practising in such a way that you play the notes correctly is a necessary precondition to even getting started with anything useful. If the way you are practising consistently results in lots of wrong notes, then it's not useful. So the maximum speed you should be practising at is one at which you can play the right notes. You absolutely must, of course, then attend to all the issues of mechanics necessary in order to play those notes both better and faster.

Playing the right notes is necessary but not sufficient. 

[nick]

OK. Thanks for the clarification.

I think the misunderstanding was that I never meant to suggest it was enough to "SIMPLY practise the notes correctly". Of course it isn't. All I meant was that practising in such a way that you play the notes correctly is a necessary precondition to even getting started with anything useful. If the way you are practising consistently results in lots of wrong notes, then it's not useful. So the maximum speed you should be practising at is one at which you can play the right notes. You absolutely must, of course, then attend to all the issues of mechanics necessary in order to play those notes both better and faster.

Playing the right notes is necessary but not sufficient.  

My point exactly. And the "tweaking" was the other elements, but the foundation is notes, rhythm, tempo.
Nick

Nick

[dima_76557]

@ falala & nick

At the risk of sounding like a nerd, very often, especially in the virtuoso repertoire, the best solution to a technical problem is SKIPPING notes (filling them in much later), provided that the basic rhythm of the piece and the body dynamics of motion are maintained.
P.S.: You thus create long lines in your head and your body starts feeling where it has to go. The skipped notes then easily fall into place. Sometimes this solves a problem in 10 minutes, while the traditional training of all the correct details at once could take months.

[nick]

@ falala & nick

At the risk of sounding like a nerd, very often, especially in the virtuoso repertoire, the best solution to a technical problem is SKIPPING notes (filling them in much later), provided that the basic rhythm of the piece and the body dynamics of motion are maintained.
P.S.: You thus create long lines in your head and your body starts feeling where it has to go. The skipped notes then easily fall into place. Sometimes this solves a problem in 10 minutes, while the traditional training of all the correct details at once could take months.

I can see where this could work for some people. I don't do this but do something similar in a way, in that on some difficult parts get the main notes firmly in my mind and lightly play the surrounding notes very lightly, often changing fingering back and forth, sometimes after a week trial or more. This sounds similar to " the long lines in one's head". But I never skip notes.
  Tell me, after you do this and you are playing correctly all the notes, is it possible to see where you went wrong, how you were not able to play them all before? I was thinking you could learn from that and then not need to do it, unless you like it. Since the result may be the same.  No harm I guess.

Nick

[falala]

@ falala & nick

At the risk of sounding like a nerd, very often, especially in the virtuoso repertoire, the best solution to a technical problem is SKIPPING notes (filling them in much later), provided that the basic rhythm of the piece and the body dynamics of motion are maintained.
P.S.: You thus create long lines in your head and your body starts feeling where it has to go. The skipped notes then easily fall into place. Sometimes this solves a problem in 10 minutes, while the traditional training of all the correct details at once could take months.

Yes, I can see how that would work.

To clarify: what I meant by playing "the right notes" is simply playing the notes that one INTENDS to play. This could be all kinds of things other than playing the whole piece literally as is. It could mean playing short sections; one hand at a time; one voice at a time; and yes - playing various "skeleton" versions of the piece as you describe.

But ultimately, it all comes back to having a clear idea what one intends to play, and playing it.

When one isn't already in the position of being able to play a virtuosic piece note perfectly up to speed, one has to make various compromises about the intention. This may consist of compromising speed, number of hands, length of section to be practised, amount of detail or whatever. But having made the compromise, one plays what one intended to play. Then work on reducing the compromises.

[dima_76557]

 Tell me, after you do this and you are playing correctly all the notes, is it possible to see where you went wrong, how you were not able to play them all before?

What I wrote was not to prove anything about "right" or "wrong". It was intended to get the "slow" and "fast" factor into perspective.

The problem with some new pieces we are trying to learn is that there can be so many details that one is forced to practise VERY slowly to get them all, so slowly that one forgets about the driving force, the pulse, the heartbeat of the piece.

Without that basic pulse, however, you can't solve technical problems satisfactorily. Most technical problems are actually musical problems, you see? In many virtuoso works, one is actually better served by temporarily playing clusters in between the "main ideas" than by getting all the notes right, otherwise the music dies in the process of all that slave labor.

Doing it that way, it won't feel "fast", but it will still be "musically satisfactory". It will also save lots of time, and the end result will be better in all respects without a doubt.

[nick]

The problem with some new pieces we are trying to learn is that there can be so many details that one is forced to practise VERY slowly to get them all, so slowly that one forgets about the driving force, the pulse, the heartbeat of the piece.

I practice all of my pieces VERY Slowly at first precisely for that reason! (getting all the details) I can hear the music coming through even though it is very slow. The speed pics up in a pretty short time to a reasonable speed by repetition. Fingering is sometimes arrived at by playing a small part very fast.  But the logic of skipping notes at first escapes me. Every single note is learned and and then repeat, repeat repeat. I am a plodder I guess, and it always seems to work, and much older than you I assume. Oh well, to each his own. Good luck.

Nick

[toomuchpolitics]

Personally I find this type of practice extremely useful when my students or I want to gain evenness and speed:

.

I teach op13 a lot.  Would you like me to make you a little video with some practice suggestions?  I'm happy to do that for you - no charge! Just let me know.

[timothy42b]

I have an example from the trombone world
(maybe it has no application to piano, I dunno; nyi usually jumps in about now to insult me)

Listen to Rolling Thunder

We're attempting it in one of the community bands I play in
Now understand that community bands are groups of fun loving amateurs with no audition requirements

A piece like this is within the grasp of top conservatory bands like Eastman or Dallas or most but not all military bands, but taken at tempo is way beyond virtuosic for many groups

To play this at MM 160 demands clean double tonguing and fast accurate slide technique

Neither can be developed moving slowly   So the way most amateur trombone players attempt this is to start somewhere about MM 60 or 70 and put it up one beat a week, and utterly fail no matter how long they live

While all the pros can do this one, I'm the only amateur I know who can pull it off
I learned it at tempo, setting the metronome to 160, and playing the whole measure but not changing the note, then changing one note, then changing two notes, etc

Now that I can play it at speed, I am trying to refine it, making it cleaner and working out minor intonation faults   I have to slow down to do that, but I use the same technique as when playing fast  You can't hear all those problems at speed in normal acoustic settings but I know I can continue to get this one better and better

[lostinidlewonder]

You practice slow and fast but how is the critical point. There is no point doing either mindlessly or uncontrollably.

You can use controlled pausing between parts which are causing you the most problems. Controlled pausing means you freeze your hands and only move when you know where to go next.

Everything you play even while practicing should highlight a controlled effortless technique. If you feel tense then something is wrong. Practice so you only feel comfortable, practice so you can still hear what you are playing, there is no use going so slow that you lose the musical context.

Using correct fingering is the most important issue, there is no use practicing with bad fingering.

You can also practice with different rhythms, neglected notes, create exercises to act as a catalyst to improve your technical problems etc etc.


These ideas are all easy to talk about but where exactly in the music do you apply it? Are all your fingerings correct? So many issues that cannot be solved with writing unless you have context to discuss.

[themusne]

     I am always taught to practice a piece very slowly first.But I have a stupid question to ask,anyone care to answer?If I have "no technical problem" when I play a  piece with fast tempo,why do I have to practice slowly?

[outin]

     I am always taught to practice a piece very slowly first.But I have a stupid question to ask,anyone care to answer?If I have "no technical problem" when I play a  piece with fast tempo,why do I have to practice slowly?

Why do you have to?

Practicing slowly does ensure better memorization and helps you avoid tension and mind your tone, but I see no reason why you can't alternate between fast and slow in the process of learning a piece. What works best also depends on what kind of a learner you are.

[j_menz]

If I have "no technical problem" when I play a  piece with fast tempo,why do I have to practice slowly?

Why do you have to practice it at all if that's the case?

[lazyfingers]

If you can't do something slowly, then what makes faster possible?

[outin]

If you can't do something slowly, then what makes faster possible?

Can't speak for anyone else, but for me slow can sometimes be more difficult because of how the memory functions. If I have learned things as "chunks", doing them very slowly can break the connection.

[lazyfingers]

Can't speak for anyone else, but for me slow can sometimes be more difficult because of how the memory functions. If I have learned things as "chunks", doing them very slowly can break the connection.

I am not referring to something written to be purposely slower than faster. I find the second movement of the Waldstein more difficult than the rest. Mainly because of the control that is entailed. Slow is actually more difficult than fast in that context.

However, for a fast piece to be played slow, if someone can't play that slowly, than it would probable not work well if played fast. If you can't play the 4th movement slowly, then prestissimo might be too much for you.

[dima_76557]

    I am always taught to practice a piece very slowly first.But I have a stupid question to ask,anyone care to answer?If I have "no technical problem" when I play a  piece with fast tempo,why do I have to practice slowly?

To develop and maintain quality and control, I guess. Exclusive and repeated fast practice tends to blur the quality of the end result (more and more details become unclear, mistakes start slipping in, etc.). I may be mistaken, but exclusive fast practice may also trigger performance anxiety (making you too nervous before an actual performance), depending on what kind of person you are.

P.S.: Even an inimitable maestro like Shura Cherkassky practised very slowly, even though he could clearly play everything a lot faster than required. We can actually see him do it at 7:13 in this clip of a rare interview with him:

At 0:51 of that same clip, he tells us how and why he does that. Although this may seem very mechanical to bystanders, it was a required procedure for the "last of the Romantics".

[outin]

However, for a fast piece to be played slow, if someone can't play that slowly, than it would probable not work well if played fast. If you can't play the 4th movement slowly, then prestissimo might be too much for you.

True.

I find it easier to first get a grasp of the piece in somewhat faster tempo before doing very slow practice. I wasn't thinking about playing at full tempo right away.  But practicing REALLY slowly seems always quite difficult...

[lazyfingers]

True.

I find it easier to first get a grasp of the piece in somewhat faster tempo before doing very slow practice. I wasn't thinking about playing at full tempo right away.  But practicing REALLY slowly seems always quite difficult...

It always amazes me that people claim that fast practice is the way to go. Excluding as you say an initial fast go to understand how it might go in terms of musicality, fingering etc. But practice itself?

Nothing whatsoever in human endeavour is ever practiced at performance speed! No runner ever learns to run at sub 4 minute mile, or sub 10 sec 100 metres! Why do we think we can do things at break neck speed for anything more complex than putting one foot in front of the other!

Once we sort out what fingering to use for breakneck speed (to which end we have endless assistance with fingering advice from whomever), it doesn't follow logically that we have to practice that same fingering at breakneck speed in order to perform at that speed.

[outin]

Once we sort our what fingering to use for breakneck speed, it doesn't follow logically that we have to practice that same fingering at breakneck speed in order to perform at that speed.

Then of course we agree

[lazyfingers]

But practicing REALLY slowly seems always quite difficult...

Having read this again, I agree. Bach's Fugues are killers when practiced slowly. But that is the only way to learn them and to get the notes precisely legato and synchronous.