While digital technologies offer a host of new sonic possibilities, we are no longer dealing with the physical vibrations of strings, tubes and solid bodies as the sound source, but rather with the impalpable numerical streams of digital signal processing (DSP). As a result, when we perform with digital musical instruments (DMIs), we can no longer make use of haptic feedback provided through the body of the instrument itself. Furthermore, many DMIs are derived from interfaces designed for effortlessly smooth human-computer interaction. Here, however, the struggle afforded by the resistance and physical forces of acoustic instruments, which I will argue is integral to musical performance, is all but lost. This paper discusses the musical outcomes of an exploration into the use of a haptic interface as an instrument for the performance of digital music. I will argue that it is the reintroduction of these tangible forces that is crucial for the articulation and effectuation of sonic ideas. In particular, the instrument will be discussed in relation to the work Running Backwards, Uphill (2011) for piano trio and live electronics, where a potentially high level of sophistication of expression was required that would allow the laptop performer to embody the musical intentions of the piece.