Effects of recruitment, rate coding and twitch property noise on the variability and complexity of muscle force: a simulation study

The magnitude and complexity of skeletal muscle force variability has been shown to change e.g. with different force levels [1], with fatigue [1], and with ageing. The purpose of this study was to use motor unit models to determine how the location of noise inputs affect variability at different activation levels. Models that changed whether a motor neuron (mu) fires and its firing rate and noise in the twitch parameters had the largest effects on force magnitude and complexity.