Background Long-term piano training might induce some biochemical and structural adaptations in the intrinsic muscles of the hand or change the motor strategy of the nervous system. The main purpose of this study was to analyze whether the intrinsic muscles of the hands of pianists and sedentary controls differ in electromyographic characteristics at different strengths. Methods Fifteen college piano students and 15 sedentary controls were asked to sit on an examination bench and perform first dorsal interosseous muscle contractions for 1 minute. The motor unit potentials were recorded during various percentages of maximal voluntary muscle contraction (MVC) by automatic decomposition electromyography. Results The pianists demonstrated a significantly higher firing rate, shorter duration, and higher amplitude of motor unit potentials during minimal muscle contractions than the sedentary controls. But when comparing all the parameters at other degrees of contractions, the pianists were found to have significantly higher firing rate only at 25% and 50% of MVC, and higher amplitude at maximal contraction than the control group. The amplitude at maximal control contraction was higher in pianists than in controls. Conclusion These results imply that high-frequency and highly efficient muscle fibers are recruited in pianists when minimal muscle contractions are performed, which also indicate that by using smaller motor units, pianists may delicately control their fine motor performance.