Inter-limb coupling in individuals with transtibial amputation during bilateral stance is direction dependent

Peter C. Raffalt, Jenny A. Kent, Nick Stergiou*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We investigated the control of upright standing in individuals with unilateral transtibial amputation (TTA) by assessing the inter-limb coupling and the coupling between the center of pressure beneath both limbs combined (COPNET) and the center of pressure (COP) beneath the prosthetic limb and the intact limb. Twenty-one adults with TTA and eighteen unimpaired adults completed 90 s of standing on two parallel force plates. The inter-limb coupling and the coupling between the COP beneath each limb and the COPNET were assessed by quantifying the synchronization of the COP signals. This included the number of epochs with synchronized signals, the total duration of signal synchronization and the relative phase and deviation phase between the signals. Additionally, magnitude and temporal characteristics of the COP displacements were quantified. Individuals with TTA exhibited looser inter-limb coupling in the anterior-posterior direction, characterized by more shifts between epochs with synchronized signals, shorter total duration of signal synchronization, less in-phase coordination patterns and a higher deviation phase between the two limbs, compared to unimpaired individuals. This coincided with a larger and more irregular postural sway in the TTA group. No group difference was observed in the mediolateral direction. The coupling between the COPNET and the COP beneath the individual limbs was similarly direction dependent, and tighter for the intact side, suggesting that an intact limb-driven strategy was utilized.

Original languageEnglish
Article number102861
JournalHuman Movement Science
Volume79
ISSN0167-9457
DOIs
Publication statusPublished - 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 Elsevier B.V.

Keywords

  • Center of pressure dynamics
  • Phase synchronization
  • Postural control
  • Prosthesis

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