Hand span and digital motion on the keyboard: concerns of overuse syndrome in musicians

To investigate the hand motion of pianists when they performed an octave and a chord, which accounted for 74% of the piano techniques that the subjects practiced at the onset of overuse hand problems. The octave position was to strike 2 keys that were 16.7 cm apart simultaneously with the thumb and small finger, and the chord position was to strike 3 keys with 4.8 cm between the borders.

The abduction angle of both the thumbs and the small fingers of 10 pianists while playing a chord and an octave were measured repeatedly with a video-based passive marker detection system. The angles were compared between pianists with large hand spans and those with small hand spans.

When playing the octave both the maximal and minimal abduction angles of the thumb were significantly larger for the smaller-hand pianists as compared with the pianists with larger hand spans. When playing the chord the maximal abduction angle of the thumb of small-hand-span pianists was significantly larger than that of large-hand-span pianists. The abduction of the small finger, however, did not differ during performance of either the octave or the chord.

These results suggest that the small-hand-span pianists must abduct the thumb more than large-hand-span pianists while minimizing movement of the small finger. This may cause de Quervain's tenosynovitis in pianists.