Muscle Synergies and Coherence Networks Reflect Different Modes of Coordination During Walking

Jennifer N. Kerkman, Annike Bekius, Tjeerd W. Boonstra, Andreas Daffertshofer*, Nadia Dominici

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


When walking speed is increased, the frequency ratio between the arm and leg swing switches spontaneously from 2:1 to 1:1. We examined whether these switches are accompanied by changes in functional connectivity between multiple muscles. Subjects walked on a treadmill with their arms swinging along their body while kinematics and surface electromyography (EMG) of 26 bilateral muscles across the body were recorded. Walking speed was varied from very slow to normal. We decomposed EMG envelopes and intermuscular coherence spectra using non-negative matrix factorization (NMF), and the resulting modes were combined into multiplex networks and analyzed for their community structure. We found five relevant muscle synergies that significantly differed in activation patterns between 1:1 and 2:1 arm-leg coordination and the transition period between them. The corresponding multiplex network contained a single module indicating pronounced muscle co-activation patterns across the whole body during a gait cycle. NMF of the coherence spectra distinguished three EMG frequency bands: 4–8, 8–22, and 22–60 Hz. The community structure of the multiplex network revealed four modules, which clustered functional and anatomical linked muscles across modes of coordination. Intermuscular coherence at 4–22 Hz between upper and lower body and within the legs was particularly pronounced for 1:1 arm-leg coordination and was diminished when switching between modes of coordination. These findings suggest that the stability of arm-leg coordination is associated with modulations in long-distant neuromuscular connectivity.

Original languageEnglish
Article number751
Pages (from-to)1-13
Number of pages13
JournalFrontiers in Physiology
Issue numberJuly
Early online date24 Jul 2020
Publication statusPublished - Jul 2020


This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (“Learn2Walk”; Grant Agreement No. 715945) and the Dutch Organisation for Scientific Research (NWO) VIDI grant (“FirSTeps”; Grant Agreement No. 016.156.346).

FundersFunder number
Horizon 2020 Framework Programme715945
European Research Council
Nederlandse Organisatie voor Wetenschappelijk Onderzoek016.156.346


    • electromyography
    • interlimb coordination
    • locomotion
    • muscle networks
    • muscle synergies


    Dive into the research topics of 'Muscle Synergies and Coherence Networks Reflect Different Modes of Coordination During Walking'. Together they form a unique fingerprint.

    Cite this