Motor-unit recruitment in VDU tasks: a methodological analysis

摘要

A prevalent ailment among operators at computer terminals is chronic shoulder pain of the myalgia type, localized to the trapezius muscle. It is hypothesized that such pains are due to overuse of low threshold motor-units. However, it is not known if a stereotypic discharge pattern is at hand in practical working situations. The present study introduces multi-lead fine wire electrodes for signal acquisition in experimental situations miming computer and other types of light manual work. Signal decomposition using motor-unit action potential (MUAP) residuals was applied with partial success. Preliminary results using these techniques indicate that there are low threshold motor-units which are active in different arm postures, in static and dynamic conditions as well.