Characteristics of postural corrective responses before and after Long-Term spaceflights

Dimitry Sayenko, A. A. Artamonov, I. B. Kozlovskaya

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Balance function is dramatically deteriorated after exposure to microgravity. The purpose of the present study was to investigate the role and the contribution of different gravity sensory systems to the development of balance impairment after long-term spaceflights. Postural perturbations (pushes to the chest) of the threshold, medium, and sub-maximal intensities were produced in eight cosmonauts before, and on the day 3, 7, and 11 following spaceflight. Postural corrective responses were analyzed by anterior-posterior body sway fluctuation and electromyographic activity of leg muscles. The characteristics of the postural corrective responses changed significantly on the day 3 following spaceflight: the amplitude of posterior sway caused by perturbation of threshold intensity was increased reaching 135% of preflight value; the corrective responses lasted more than 6 s in 50% of all trials, while it did not last more than 4 s in 96% before spaceflight. The EMG responses were characterized by increased contribution of medium- and long-latency reactions. On the day 11 following spaceflight, most of the characteristics of postural corrective responses were close to preflight values. We assumed that the balance alterations after spaceflight are caused by changes in weightlessness of functions of two main gravity sensory systems, namely, weight-bearing and vestibular one. The deficit of weight-bearing afferentation triggers a decline of the extensors' muscle tone, while changes of vestibular function cause a decline of accuracy of postural corrections.

Original languageEnglish (US)
Pages (from-to)594-601
Number of pages8
JournalHuman Physiology
Volume37
Issue number5
DOIs
StatePublished - Sep 1 2011

Keywords

  • muscle tone
  • postural corrective responses
  • space flight
  • support afferentation
  • vestibular apparatus

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Fingerprint Dive into the research topics of 'Characteristics of postural corrective responses before and after Long-Term spaceflights'. Together they form a unique fingerprint.

Cite this