Positive afferent feedback to the human soleus muscle during quiet standing

Johan van Doornik, Christine Azevedo Coste, Junichi Ushiba, Thomas Sinkjær

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Introduction: In this study we investigated the mechanisms responsible for soleus muscle contraction during quiet standing. Methods: Subjects stood on a platform that was randomly moved forward or downward or rotated around the ankle. Results: Downward perturbation caused a shortlatency drop in averaged rectified soleus electromyography (SOL EMG). SOL drop increased monotonically with downward acceleration amplitude. Ischemia above the knee abolished or diminished this drop. Ischemia above the ankle had no diminishing effect. Vibration of the Achilles tendon had a diminishing effect on the amplitude of SOL responses. Conclusions: The short-latency drop in SOL observed for downward perturbation might be due to a decrease in positive afferent feedback due to the sudden decrease in body weight. This implies the existence of an ongoing afferent feedback loop toward the SOL motoneuron pool from force-sensitive receptors. Both Ia and Ib afferents probably play a role in the responses observed.

Original languageEnglish
Pages (from-to)726-732
Number of pages7
JournalMuscle and Nerve
Volume43
Issue number5
DOIs
Publication statusPublished - 2011 May 1

Keywords

  • Afferent feedback
  • Ground perturbation
  • Postural control
  • Posture
  • Standing

ASJC Scopus subject areas

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)

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