Motion analysis of the fingers and wrist of the pianist

To better understand the injury mechanism associated with overuse syndromes of pianists, it is necessary to simultaneously measure the position and range of motion of hand and wrist joints. A system that allows such simultaneous measurement is described. It is a video-based passive marker detection system that calculates the three-dimensional positions of retro-reflective markers placed on the forearm, hand, and fingers. The tracking of these markers allows for the calculation of the different joint angles over time. Ten pianists were studied while playing a scale and a chord passage to demonstrate the feasibility of the new system. Motion analysis of the performance of the scale passage demonstrated primarily flexion of the metacarpophalangeal (MCP) joint at the striking key and extension at the proximal interphalangeal (PIP) joint. In contrast, playing of the chord passage required repeated flexion predominantly at the wrist joint. The maximum extension angle of the wrist in scale was significantly smaller than that in chord. However, the maximum extension angle of the MCP and PIP joints in scale were much larger than those in chord, and the maximum flexion angle of the distal interphalangeal (DIP) joint in scale was much larger than that in chord. These results showed that while there are many variations of finger motion and position in playing the piano, specific joints can be identified that are affected to a greater extent in repetition of motion. This developed motion measurement system has been found to be feasible for studying joint movement in piano performance.