Fine motor control is achieved through the coordinated activation of groups of muscles, or "muscle synergies." Muscle synergies change after stroke as a consequence of the motor deficit. We investigated the pattern and longitudinal changes in upper limb muscle synergies during therapy in a largely unconstrained movement in patients with a broad spectrum of poststroke residual voluntary motor ca...

We recently showed that four muscle synergies can reproduce multiple muscle activation patterns in cats during postural responses to support surface translations. We now test the robustness of functional muscle synergies, which specify muscle groupings and the active force vectors produced during postural responses under several biomechanically distinct conditions. We aimed to determine whether...

This paper explores the concepts of synergy, economies of scope and complementary in an attempt to refine the concept of synergy. The paper develops a taxonomi consisting of four kinds of synergies: 1)The static and subadditive synergies consisting of economies of scope and asset amortization benefits, 2) the static and superadditive synergies known from the treatment by Ansoff (1965), 3) the d...

In daily lives, humans successfully transit their motions rather than performing separate movements. It has been widely acknowledged that there are four and five modules (called muscle synergy) in human sit-to-stand and walking motions, but it was still unclear how humans activate their redundant muscles to transit their movement from sitting to walking. Therefore this study hypothesize that hu...

Matrix factorization algorithms are commonly used to analyze muscle activity and provide insight into neuromuscular control. These algorithms identify low-dimensional subspaces, commonly referred to as synergies, which can describe variation in muscle activity during a task. Synergies are often interpreted as reflecting underlying neural control; however, it is unclear how these analyses are in...

Analyses of experimental data acquired from humans and other vertebrates have suggested that motor commands may emerge from the combination of a limited set of modules. While many studies have focused on physiological aspects of this modularity, in this paper we propose an investigation of its theoretical foundations. We consider the problem of controlling a planar kinematic chain, and we restr...

21 Recent evidence suggests that complex spatiotemporal patterns of muscle activity can be 22 explained using a low-dimensional set of muscle synergies or M-modes. While it is clear that 23 both spatial and temporal aspects of muscle coordination may both be low-dimensional, 24 constraints on spatial versus temporal features of muscle coordination likely involve different 25 neural control mech...

Much debate has arisen from research on muscle synergies with respect to both limb impedance control and energy consumption. Studies of limb impedance control in the context of reaching movements and postural tasks have produced divergent findings, and this study explores whether the use of synergies by the central nervous system (CNS) can resolve these findings and also provide insights on mec...

Investigation of neural representation of movement planning has attracted the attention of neuroscientists, as it may reveal the sensorimotor transformation essential to motor control. The analysis of muscle synergies based on the activity of agonist-antagonist (AA) muscle pairs may provide insight into such transformations, especially for a reference frame in the muscle space. In this study, w...

Recent evidence suggests that complex spatiotemporal patterns of muscle activity can be explained with a low-dimensional set of muscle synergies or M-modes. While it is clear that both spatial and temporal aspects of muscle coordination may be low dimensional, constraints on spatial versus temporal features of muscle coordination likely involve different neural control mechanisms. We hypothesiz...