I see a MIDI project on the horizon. Operon from the openprosthetics group writes -

This is a step-by-step guide on how to make your very own prototype acoustic myography sensor. That means a sensor you can use to measure muscle sounds. What is this good for? well… it is a more affordable alternative to the electrodes used in powered prostheses (specially if you make your own). The short paper below describes briefly how this sensor works and the diagram illustrates how it is built.

instructables : Measure Muscle Sounds! Part 1: Electronic Board – Link.