Thomas Mark: What Every Pianists needs to know about the body (2003, GIA Publications, Chicago)

(中譯)
[p.142-3] According to some studies, doubling the force multiplies stress on the tendons not by two but by five. Depressing keys on the piano does not require much force; the standard touch weight for a well-regulated piano is only 50g, about the weight of 10 U.S. five-cent pieces. It is easy for pianists to fall into the habit of using more force than needed, and because of the extremely high levels of repetition involved in piano playing, excessive force is potentially injurious.

How does it come about that a good pianist may play in a way that stresses the body? I think there are two principal reasons. First, most people’s technique is not deliberately chosen. That is, the person does not analyze the movements needed to play a passage and practice those movements. Instead, the person just finds a way, by hook or crook and trial and error, to get to the right notes. With constant repetition the movements become habits. Sometimes, movements acquired this way will be efficient. But there is no guarantee. Our bodies can become used to inefficient movements as well as efficient ones, when we are used to them, the inefficient ones feel “normal.” The movement that can cause injury do not necessarily feel bad or painful. Indeed, they are not dangerous in non-repetitive tasks. They are dangerous for pianists because piano playing is extremely repetitive.

The second way in which people come to move stressfully is that they are taught stressful movements. No teacher would knowingly teach harmful movements. But too few teachers understand the principles of efficient movement, and some ways of moving that are dangerous to our health are firmly established in traditional pedagogy.