Voluntary and reflex muscle synergies in upper limbs

Tytus Wojtara, Fady Alnajjar, Shingo Shimoda, Hidenori Kimura

Research output: Chapter in Book/Report/Conference proceedingChapter

2 Citations (Scopus)


It is known that the human muscles can be controlled both intentionally and by automatic responses. However how exactly the neural signals received by the muscles are produced is still unknown. One of the concepts created to answer this question are the muscle synergies. This concept however, doesn’t take into account whether the neural signals are of voluntary or involuntary origin. Most researchers apply this concept to analyze exclusively automatic responses or exclusively voluntary movements or both without distinguishing between them. We propose an extended synergy model that explicitly accounts for both voluntary and involuntary neural signals and try to verify it experimentally.We examine reaching movements with and without constraints that provoke automatic responses. The general goal of this research is the creation of a measure of recovery level in upper limb rehabilitation after brain stroke, as well as, a rehabilitation assisting device. We introduce the synergy stability index and with experiments we show that the synergy stability is lower for movements with disturbance that provoke an involuntary movement.

Original languageEnglish
Title of host publicationBiosystems and Biorobotics
PublisherSpringer International Publishing
Number of pages6
Publication statusPublished - 2013
Externally publishedYes

Publication series

NameBiosystems and Biorobotics
ISSN (Print)2195-3562
ISSN (Electronic)2195-3570

ASJC Scopus subject areas

  • Biomedical Engineering
  • Mechanical Engineering
  • Artificial Intelligence


Dive into the research topics of 'Voluntary and reflex muscle synergies in upper limbs'. Together they form a unique fingerprint.

Cite this