Musicians injuries are surprisingly common. There is limited knowledge behind the biomechanics of pianist performance. This study presents the development of a novel instrumented piano key with integrated strain-based sensors that unobtrusively measures the force applied during finger-key interaction in pianists. Pianist perception of touch was experimentally assessed to determine sensitivity to changes in key mass properties. In general, pianists were unable to identify significant changes in the mass of the key. The prototype key successfully identified components of contact force and location. Design refinements are presented that will enable a second prototype to completely measure all components of the contact force and its location. The accuracy, precision, and resolution of data collected from this prototype clearly indicate that an instrumented key can be integrated in a piano to assess the fifinger key interactions in piano performance.