Motor Redundancy: the problem of degrees of freedom in human movement science

Abstract

The purpose of this paper is to present a tutorial and applied view of motor redundancy, that is, the critical problem of redundant degrees of freedom in human movement that the central nervous system must deal with. Although extensive scientific work has been done over the past decades, the motor redundancy problem, originally postulated by Bernstein, is still an unresolved and exciting topic for researchers interested in understanding how the brain controls voluntary movements. In our attempt to summarize the development of this scientific problem and researchers’ efforts to understand it, we discuss theoretical approachesand applied studies from the last 40 years. Our discussion focuses on the central nervous system’s ability to control the infinite number of degrees of freedom that exist in human movements. Lastly, we indicate that there is still a vast area of study requiring new analytical strategies and a multidisciplinary perspective for a fuller understanding of how the human brain controls bodily movement.