This sounds like a very interesting book!
It seems to me that most if not all musical instruments have the potential for causing pain, repetitive motion injury and at least discomfort.
Is there a musical instrument that involves only natural body motions? Maybe the Kazoo.
I'm currently trying to learn how to play guitar, and my left hand hurts because I'm trying to bend my fingers in un-natural ways.
Yes - all instruments do - musicians of all types get injured at approximately the same same rate... but the injuries of non-symmetrical instrumentalists such as guitar or the flute are 2x as severe, on average.
re: natural movements.... The trick is to figure out natural movements that operate the instrument. Natural movements are the most efficient anyway