Dynamic performance of vibration induced anterior-posterior sway during upright posture in normal subjects.
Human postural control works as a dynamic feedback control system. The dynamic performance of postural control for anterior-posterior movements during upright posture are defined by three parameters. These parameters reflect the stiffness, the damping and the swiftness of a response to an induced perturbation. In the present study 23 normal subjects were investigated. Both with open and closed eyes, there was a negative correlation between swiftness and stiffness. With open eyes there was also a weak correlation between swiftness and damping. When the subjects were tested with open eyes there was a prominent and highly significant increase of stiffness and a reduction of swiftness of the responses. It was found that proprioceptive information from the calf muscles contributes in postural control of movements up to 1 Hz and visual information is important for movements up to 0.05 Hz. The present findings suggest that postural control changes dynamic strategies depending on the available sensory feedback.
Magnusson
M
M
Department of Oto-Rhino-Laryngology, University Hospital, Lund, Sweden.
Johansson
R
R
D000293:Adolescent; D000328:Adult; D005246:Feedback; D006801:Humans; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D014732:Vibration; D014785:Vision, Ocular / Q000502:physiology