title: Over-stimulation of the vestibular system and body balance.
abstract: The purpose of this study was to examine whether an over-stimulation of the vestibular system, induced by thousands of time saccadic head stimulations, affects the vestibular sensitivity, and consequently if such a phenomenon could contribute to the deterioration of postural stability observed after a long distance running exercise. Eighteen athletic subjects performed a 20.5 km over ground race with an average speed of 15 km x h(-1), corresponding roughly to 7,500 strides shocks with associated saccadic accelerations transmitted to the head. A preliminary validation of the exercise protocol was realized to confirm the effect of the sustained exercise on body balance by recording standard postural parameters. A visually perceived eye level (VPEL) task was used to indirectly assess otolithic sensitivity motionless or undergoing low centrifugation conditions, before and after exercise. Results obtained from body balance analysis confirmed a decreased postural stability illustrated by increased postural oscillations after the 20.5 km run. Under low centrifugation conditions, results showed a lowering of the VPEL with the increase of the gravito-inertial acceleration in accordance with the literature. However, no significant change in the VPEL after a sustained running exercise was observed. In conclusion, the vestibular sensitivity at the otolithic level does not seem to be altered by an intensive running exercise and then failed to play a key role in the post-exercise deterioration of postural stability.
authors.affiliation: Centre de Recherches du Service de Santé des Armées, Département des Facteurs Humains, La Tronche - Grenoble, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Charles
authors.forename: Corinne
authors.initials: C
authors.lastname: Cian
authors.forename: Vincent
authors.initials: V
authors.lastname: Nougier
authors.forename: Xavier A
authors.initials: XA
authors.lastname: Bigard
authors.forename: Agnés
authors.initials: A
authors.lastname: Job
authors.forename: Christian
authors.initials: C
authors.lastname: Raphel
mesh_terms: D000054:Acceleration; D000328:Adult; D005403:Fixation, Ocular; D006112:Gravitation; D006801:Humans; D008297:Male; D009991:Oscillometry; D010037:Otolithic Membrane / Q000502:physiology; D004856:Postural Balance / Q000502:physiology*; D012420:Running / Q000502:physiology*; D012438:Saccades; D014722:Vestibule, Labyrinth / Q000502:physiology*