title: Postural control and contingent negative variation during transient floor translation while standing with the ankle fixed.
abstract: BACKGROUND
  Adaptation changes in postural muscle activity and anticipatory attention were investigated with the ankle joint fixed to change postural control strategies during transient floor translation.
  
  
  METHODS
  For 15 healthy young adults, 40 transient floor translations (S2) in the anterior direction were applied 2 s after an auditory warning signal (S1), under conditions with or without fixation of the ankle. Activity of the frontal postural muscles (tibialis anterior (TA), rectus femoris (RF), rectus abdominis) and contingent negative variation (CNV, brain potential) were analyzed for 20 trials each of the early and latter halves under each fixation condition.
  
  
  RESULTS
  With fixation, peak amplitude of muscle activity after S2 was significantly decreased in TA and increased in RF. These muscles showed marked adaptive decreases. The early component of CNV reduced with adaptation, particularly under fixation condition. Only in RF, background activity increased just before S2, with adaptation under fixation. A significant correlation was found between timings of CNV peak and RF activation just before S2 only after adaptation under fixation.
  
  
  CONCLUSIONS
  These results suggest that the main activation muscle changes from TA to RF with fixation. Under such condition, attention would be focused on the knee with adaptation, and the need for heightening attention in the early stage may have declined. Correspondingly, the timing to heighten stiffness of the RF became later, and attention would have been paid to RF activation just before S2.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Vitalii
authors.initials: V
authors.lastname: Lytnev
authors.affiliation: Department of Sports and Health, Kanazawa Gakuin University, 10 Sue-machi, Kanazawa, 920-1392, Japan. fujikatu@kanazawa-gu.ac.jp.
authors.forename: Katsuo
authors.initials: K
authors.lastname: Fujiwara
authors.affiliation: Department of Rehabilitation, Japan Health Care College, 6-17-3 Megumino-nishi, Eniwa, 061-1373, Japan.
authors.forename: Naoe
authors.initials: N
authors.lastname: Kiyota
authors.affiliation: Department of Rehabilitation Science, Osaka Health Science University, 1-9-27 Tenma, Kita-ku, Osaka, 530-0043, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Irei
authors.affiliation: Department of Sports and Health, Kanazawa Gakuin University, 10 Sue-machi, Kanazawa, 920-1392, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Toyama
authors.affiliation: Department of Physical Therapy, Hokkaido Bunkyo University, 5-196-1 Kogane-chuo, Eniwa, 061-1449, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Yaguchi
mesh_terms: D000161:Acoustic Stimulation; D000222:Adaptation, Physiological; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D004856:Postural Balance / Q000502:physiology*; D011187:Posture; D055815:Young Adult
keywords: Contingent negative variation; Floor translation; Joint fixation; Postural control