This question is repeatedly raised in many emails I receive from young pianists and will certainly be asked many more times.
This sentence was sent to me recently (2023) by one of my students by video and in fact it alone suffices to illustrate the point of my article. In other words - he who plays slowly, progresses quickly.
Generally speaking, the basis of efficient piano technique is alternation, i.e. the ability to pass, sometimes even extremely quickly, from a state of high muscle tension to their almost complete relaxation and vice versa. This is needed to fast and precisely regulate the speed at which the weight of the Motor Apparatus (MA) falls on the keyboard and its return to a state of equilibrium, that is, to hover just over the keyboard. If the weight were to be kept on the bottom of the keyboard for too long, the overloaded fingers would bog down in the keyboard, making it impossible to achieve fast and efficient technique, and even possibly leading to permanent tendon or muscle damage! And else, if the entire weight of the MA is held too high above the keyboard, the sound will be superficial, unbalanced, and the technique will in principle be quite fast, but choppy and inaccurate due to the lack of energy to be supplied to the keys. The trick then is to quickly oscillate the entire weight of the MA with precision. While this theoretical principle is relatively easy to understand, its application can prove quite difficult, since every slightest movement must be carefully balanced, memorized and reproduced later in a well-defined sequence. If the movements are too large, the resulting excessive inertia of the arms and hands will slow down the tempo. If, on the other hand, the movements are too small, the MA won’t be able to do its work.
Most of the piano players, regardless of their level, want to play very fast right away, not realizing that fast playing is just a spectacular “tip of the iceberg”: (photo: Uwe Kils, Wikipedia), while the enormous work required to play fast with precision remains invisible. The basis of fast playing is SLOW exercise or, at most, MEDIUM TEMPO, because only then can you fully control all the necessary components of the musical text, which at the beginning of work on the piece have not yet been completely mastered.
If you start playing too fast at this early stage, you may eventually develop a certain proficiency, but your play will lack the most essential, fundamental musical elements. In other words, you must give your muscles and your brain a chance to assimilate the new text and hand layout on the keyboard. Also, don’t forget that fast playing USES and DESTROYS the model of the piece created In memory, as there can always be minor faults that are skipped when playing the fast version. Our brain registers everything, so there is a high risk that it will permanently remember a mistake and unexpectedly replace a correct reflex with it. That is why professional musicians play the entire program in medium tempo after a concert in order to REPAIR their model version, i.e. to remove accidental faults.
How to gradually increase the tempo