The definition of rubato is a flexibility/freedom in the performance of a rhythm. Basically, rubato is when a performer doesn’t stick to the strict rhythms written by the composer, but alters them to give more expression to the performance.
Rubato is one of the most controversial performing techniques in music. It divides opinion like no other aspect I can think of. On one extreme, I have heard performance coaches say that the tempo indicated by a composer must be strictly adhered to. On the other extreme, I have heard teachers say that such tempos are merely a rough guide and that the pulse in music should be forever shifting like the human pulse. I am always wary of such extreme views, but I do think there are some questions you should ask as a performer when considering the amount of rubato to use:
What are the composer’s intentions?
This is a good starting point (even if you are the composer). What is the composer trying to say through this piece of music? How is the use of rubato going to contribute to this? Sometimes this is easy to answer as the composer may have written “rubato” at the start of the piece. However, at other times it may be more complex. You may have to think about what mood/emotion the composer is looking to create – a romantic dreamy mood may be more conducive to the use of rubato than if the composer is trying to create a regimented efficient mood. In the example below, I use quite a lot of rubato in my piece “Elegy” as it is a very melancholic mood and the use of rubato helps me to express this:
What is stylistically “appropriate”?
I am very nervous about using the word “appropriate” because it opens up a whole array of controversies. However, it is worth asking whether rubato is typically used in the style of music you are playing. For example, rubato is more likely to be stylistically effective in Romantic piano music than it is in a Baroque fugue.
In the end it all comes down to this question – what do you as the performer think works for you and your audience? You can take into account the questions listed above, but you simply have to make a decision and go with it. Try it out in front of people and see what they think. Alternatively, you can try recording it with different amounts of rubato. Hearing a recording is one of the best ways of hearing what does (and sometimes more importantly) what does not work!