Countering postural posteffects following prolonged exposure to whole-body vibration: a sensorimotor treatment.

Postural stability of bulldozer operators after a day of work is investigated. When operators are no longer exposed to whole-body vibration (WBV) generated by their vehicle, their sensorimotor coordination and body representation remain altered. A sensorimotor treatment based on a set of customized voluntary movements is tested to counter and prevent potential post-work accidents due to prolonged exposure to WBV. This treatment includes muscle stretching, joint rotations, and plantar pressures, all known to minimize the deleterious effects of prolonged exposure to mechanical vibrations. The postural stability of participants (drivers; N = 12) was assessed via the area of an ellipse computed from the X and Y displacements of the center-of-pressure (CoP) in the horizontal plane when they executed a simple balance task before driving, after driving, and after driving and having performed the sensorimotor treatment. An ancillary experiment is also reported in which a group of non-driver participants (N = 12) performed the same postural task three times during the same day but without exposure to WBV or the sensorimotor treatment. Prolonged exposure to WBV significantly increased postural instability in bulldozer drivers after they operated their vehicle compared to prior to their day of work. The sensorimotor treatment allowed postural stability to return to a level that was not significantly different from that before driving. The results reveal that (1) the postural system remains perturbed after prolonged exposure to WBV due to operating a bulldozer and (2) treatment immediately after driving provides a "sensorimotor recalibration" and a significant decrease in WBV-induced postural instability. If confirmed in different contexts, the postural re-stabilizing effect of the sensorimotor treatment would constitute a simple, rapid, inexpensive, and efficient means to prevent post-work accidents due to balance-related issues.