Influence of motoneuron firing synchronization on SEMG characteristics in dependence of electrode position

and Christoph Anders. Influence of motoneuron firing syn-chronization on SEMG characteristics in dependence of elec-trode position. J Appl Physiol 91: 1588–1599, 2001.—The frequency content of the surface electromyography (SEMG) signal, expressed as median frequency (MF), is often as-sumed to reflect the decline of muscle fiber conduction veloc-ity in fatigue. MF also decreases when motor unit firings synchronize, and we hypothesized that this effect can explain the electrode-dependent pattern in our previous recordings from the trapezius muscle. An existing motoneuron (MN) model describes the afterhyperpolarization following a spike as an exponential function on which membrane noise is superimposed. Splitting the noise into a common and an individual component extended the model to a MN pool with a tunable level of firing synchrony. An analytical volum