The effects of muscle vibration on anticipatory postural adjustments

Harm Slijper, Mark Latash

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

The current study investigated the influence of changes in sensory information related to postural stability on anticipatory postural adjustments (APAs) in standing subjects. Subjects performed fast arm movements and a load release task while standing on a stable force platform or on an unstable board. We manipulated sensory information through vibration of the Achilles tendons and additional finger touch (contact forces under 1 N). Changes in the background activity of leg, trunk, and arm muscles and displacements of the center of pressure (COP) were quantified within time intervals typical for APAs. In the arm movement task, leg and trunk muscles showed a significant drop in the APAs with finger touch, while the vibration and standing on the unstable board each led to an increase in the APA magnitude. In the load release task, ventral muscles decreased their APA activity with touch, while dorsal muscles showed increased inhibition during APAs. During vibration, dorsal and ventral muscles showed increased excitation and inhibition during APAs, respectively. An additional analysis of APAs at a joint level, has shown that in both tasks, an index related to the co-activation of agonist-antagonist muscle pairs (C-index) was modulated with touch, vibration, and stability particularly in leg muscles. Small changes in the other index related to reciprocal activation (R-index) were found only in trunk muscles. Light touch and vibration induced opposing changes in the C-index, suggesting their opposite effects on the stabilization of a reference point or vertical. We conclude that the central nervous system deploys patterns of adjustments in which increased co-contraction of distal muscles and reciprocal adjustments in trunk muscles are modified to ensure equilibrium under postural instability.

Original languageEnglish (US)
Pages (from-to)57-72
Number of pages16
JournalBrain research
Volume1015
Issue number1-2
DOIs
StatePublished - Jul 23 2004

Fingerprint

Social Adjustment
Vibration
Muscles
Touch
Leg
Arm
Fingers
Postural Balance
Achilles Tendon
Muscle Contraction
Central Nervous System
Joints

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

Cite this

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The effects of muscle vibration on anticipatory postural adjustments. / Slijper, Harm; Latash, Mark.

In: Brain research, Vol. 1015, No. 1-2, 23.07.2004, p. 57-72.

Research output: Contribution to journalArticle

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