The other day I saw a video about learning to ride a bicycle that has been adjusted so that the front wheel turns left when the rider turns it to the right. If you haven't seen it, it is well worth 8 minutes. If you don't have 8 minutes, the gist of the film clip is that learning to ride a bicycle is an activity that requires a specific set of left-right balances. Once you learn those specific balances, they become unconscious. The person in this film clip taught his young son to ride a backwards-engineered bicycle, and he did so with the same degree of difficulty he would have learned to ride a conventionally-engineered bicycle. The grown-up person (who had learned to ride a conventional bicycle as a child) had a great deal more trouble. After he finally got the hang of the backwards-engineered bicycle, he could no longer ride a conventional bicycle.
After watching the video I became acutely aware of my left-right balances when playing the viola. When I would move myself from one side of the music stand to the other, the (very familiar) music felt and sounded a little bit different. A lot can be gained by changing our position in relation to the music stand when we are reading music.
But my real understanding of how the left-right balance bicycle problem relates to music making happened this morning when I was practicing the 10th Prelude from the first book of Bach's Well-Tempered Clavier (BWV 855) on the piano.
Since I spent the plastic years of childhood NOT learning how to have both hands do similar yet sometimes opposite things on the piano in order to make music move forward in a balanced, deliberate, and speedy way (particularly in the Presto section), I find this Prelude particularly difficult.
Perhaps adult pianists who try to play this Prelude with crossed hands might understand something about what the beginning adult pianist goes through concerning left and right balances.