Neuromuscular and biomechanical functions subserving finger dexterity in musicians
Exceptional finger dexterity enables skillful motor actions such as those required for musical performance. However, it has been not known whether specialized neuromuscular or biomechanical features subserve the dexterity. We aimed to identify the features firstly differentiating the finger dexterity between trained and untrained individuals and secondly accounting for the individual differences in the dexterity across trained individuals. To this aim, two studies were conducted. The first study (Study 1) compared the finger motor dexterity and several neuromuscular and biomechanical characteristics of the fingers between pianists and musically untrained individuals (non-musicians). The results showed no differences in any biomechanical features between the groups with different musical expertise. However, the pianists exhibited faster individual finger movements and more independent control of movements between the fingers. These observations indicate expertise-dependence of the finger motor skills and neuromuscular control of the fingers. The second study (Study 2) assessed individual differences in the finger dexterity between trained pianists. A penalized regression determined an association of the maximum movement speed of the pianists individual fingers with both finger muscular strength and biomechanical characteristics of the hand, but not with independent movement control between the fingers. In addition, none of these features covaried with measures of early and deliberate piano practice. Taken together, these findings indicate that distinct biological factors of finger motor dexterity differentiate between the effects of piano training and individual differences across skilled pianists.