科研之友
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摘要
Objective. - An Achilles tendon (AT) vibration is known to disrupt the postural control in standing ("vibration-induced falling", VIE) and to backward tilt the postural vertical in restrained sitting position, suggesting a link between AT vibration and internal representations involved in postural control. A recalibration of some troubles in body orientation by oriented sensory manipulations could be of great clinical interest. In order to use the VIE paradigm in a procedure suitable for a rehabilitation context, AT vibration deserves to be more investigated in sitting, for security reasons, and first in young participants. Method. - In 12 healthy participants (6 men/6 women; 23.3 +/- 1.9 years), posturographic data to AT vibrations (85 Hz) were recorded over 30 s standing and 405 sitting trials. Results. - Surprisingly, four types of differences were found between standing and sitting AT vibrations: presence/absence of VIE and kinesthetic illusion, opposite directions of the centre of foot pressure (CoP) displacements, different temporal profiles. In standing: VIE without kinesthetic illusion, rapid backward shift of CoP with a peak of -54.6 +/- 11.3 mm (with respect to baseline P < 0.001) 2.8 +/- 0.2s after vibration onset. In sitting: surprising systematic forward shift of the CoP throughout the duration of AT vibration with a maximum of 27.9 +/- 18.9 mm (P < 0.05 with respect to the baseline) 19.6 +/- 0.3 s after vibration onset, associated with a kinesthetic illusion in most subjects. Conclusion. - The present study invalidates our idea to extend in sitting the VIE paradigm but the unexpected results open a new window about the basic mechanisms underlying muscle vibration effects.
- 出版日期2013-10
