The 4rd finger is generally less mobile than the first 3 and the 5th is less powerful
There are evidently physiological reasons for this. Look up âmobility of 4th fingerâ or âringâ finger and discover the fascinating reason.
I learned about this inherent physical limitation early in my piano lessons. My teacher explained and said that was the reason for more practice! And she was right.
I didnât research it carefully today but if I remember correctly, the problem is the way the nerves, muscles, and tendons are interconnected. Finger 4 is the biggest problem - I think I was told that to independently lift the 4th finger the brain has to send signals to the muscles that lift several fingers, then at the same time, counter that by telling the non-4th fingers to stay down. Yikes.
Also, I read once that only a very small percentage of people are born with an extra muscle or tendon (canât remember the details, it was a half century ago) but regardless, there is still hope for the rest of us - we just have to work overtime to get good use from the 4th finger! I refuse to use the physical limitation as an excuse. (However, it does kind of make me wonder if some of the most famous virtuosos in the world the were born with the extra equipment. Or maybe they simply worked harder.)
There is much on the internet about exercising the fingers. Here is the first one I saw:
For me, the biggest problem to overcome was performing a key trill with the 3rd and 4th fingers, and worse, between the 4th and 5th fingers. Itâs still not as easy for me as trilling the 2nd and 3rd but did get faster and easier after years of practice. (Easier for me with the right hand than the left.) To this day I still do a lot of finger exercises, riding in a car, while reading, etc.
Such finger exercise and practice also helped me with the trumpet, horn, and guitar (and typewriter/keyboard), and although I donât play sax, oboe, etc, I suspect they have similar exercises.
Perhaps all this is one reason a teacher may suggest playing with just 3 fingers. That would avoid the need for the all that silly extra exercise and practice.
JKJ