The rhythm in piano songs is captured and later performed by the musical mind after the body has solved the technical problems such as fingering and accuracy.
There is a phrase in Ballade Pour Adeline that squeezed in it a continuous stream of demisemiquavers both in the bass clef and treble clef, as shown in Image 1 below.
Even though the time signature of the song indicates 4/4, the arrangement of the notes in the phrase shown in Image 1 meant playing 16 beats in 4 seconds. I have been taught to practice slow when learning a song for the first time, the advice has served me well and I do not doubt its soundness. However, played slow the rhythm of the phrase does not voice right.
After a couple of weeks of this, I threw caution to the wind and blazed through the phrase as fast as I could knowing I would make playing mistakes. As expected, numerous mistakes in accuracy were made but overall the rhythm I was aiming for, at last became recognizable.
From then onwards, I only had to practice landing my fingers on the keys with precision, which was a straightforward technical problem, since the musical problem with the rhythm was already solved.
It seemed odd to me that I only managed to get the rhythm right when I played up to speed. Usually I had to practice slow to get it, then build up speed incrementally. It made me think and realized that I had been practicing slow for weeks which trained my fingers, hands and arms to make roughly movements that were headed in the right direction at the piano. While my senses, hearing and vision were communicating with the mind trying to untie the rhythmic knot.
It became undone once I went back to the piano after listening to a recording of the phrase. By then, due to the effort put in since weeks earlier, mind and body were able to play correctly by listening to my memory of the recording I heard.
The effort I put in in the preceding weeks leading up to the successful execution of the phrase involved building strength in the fifth finger and gaining speed incrementally. I practiced with the phrase itself for this purpose and did not use other exercises. At the same time, listened closely to the sounds I was making and tinkered with adjustments to produce the accurate rhythm.
The accurate rhythm would not have been made possible had I not first worked on building strength in the fifth fingers of both hands. It was due to the fact that, chords consisting of notes played with the fifth fingers were present in the bass clef as well as the treble clef.
Using the actual keys involved in playing the phrase, with the fingers of my right hand I used the thumb, index and fifth finger each to press on the keys of G,B and E and rested at the bottom of the keybed. Then played C and D one at a time repeatedly using the 3rd and 4th finger. As shown in Image 2 below.
With the fingers of my left hand, I then mirrored the exercise in the bass clef by using the thumb, index and middle finger each to press on the keys of E,D and C and rested at the bottom of the keybed. Then played A and G one at a time repeatedly using the 4th and 5th finger. As shown in Image 3 below.
Another form of the exercise that is equally effective in strengthening the fifth finger is to position it on C, press down on D using the 4th finger and hold the D while playing the notes around it. Beginning with the C played by the fifth finger and ending with G played by the thumb.