In our professional careers as keyboard players, (piano, organ, and synth) we are often required to sit down and play involved polyphonic music at the drop of a hat, so to speak.
I think we can break down the issue of being warmed up for peak performance into three areas.
First, there is the issue of preparation, how we practice leading up to the performance. Many classical players recommend practicing the pieces at a slow tempo, then medium, and finally fast--even on the day of the performance. It tells one a lot about how these folks achieve and maintain a high degree of accuracy on such complex musical material. They say …