The Right Fit Matters: A 12-Millimeter Narrower Keyboard per Octave Reduces Muscle Fatigue in Pianists with Smaller Hands

Muscle fatigue and smaller hand spans are considered important risk factors of injuries for pianists. The objective of the present study was to assess the effect of keyboard size and hand anthropometry on perceived exertion and the evolution of upper-limb muscle fatigue in 20 expert pianists performing a repetitive piano task, while controlling for performance parameters. Muscle fatigue was assessed using surface electromyography (EMG), including a high-density EMG grid placed on the right posterior forearm and wireless EMG sensors on the right upper-limb muscles. The myoelectric manifestation of fatigue was quantified using variations in the median EMG frequency at different time intervals throughout the task. All upper-limb muscles exhibited fatigue. Smaller hand size was found to be a contributing factor to increased perceived exertion and muscle fatigue in finger/wrist extensor muscles. When pianists with smaller hands played on a smaller keyboard (DS6.0 keyboard), perceived exertion decreased, the radial area of finger/wrist extensors showed fewer signs of fatigue, and playing speed (tempo) was faster toward the end of the task. The DS6.0 keyboard can help reduce muscle fatigue in pianists with smaller hands. However, as hand-size and keyboard-size effects were localized in different areas of the posterior forearm, the DS6.0 keyboard might reduce but not fully mitigate hand-size disparities between pianists.