Muscles act as low-pass filters on neuromotor noise

Abstract

Recently and in the past, the concept of neuromotor noise has been used to explain a wide variety of motor control phenomenon. In this article the origin of neuromotor noise and its management by the motor system is explored by reporting an experiment on isometric force applications. Isometric force applications allow the study of force generation in its pure form, without contamination by biomechancial properties such as inertia and viscosity. It is shown that there is an optimal force level for muscles to operate at that lays around 30% of Maximum Voluntary Contraction. It is suggested that co-contraction of opposing muscle groups can be used to achieve this optimal force level in a wide range of tasks. Power Spectral Density Analysis (PSDA) of muscular force was used to distinguish several sources of neuromotor noise.