Influence of controlled masticatory muscle activity on dynamic reactive balance

Background The influence of the stomatognatic system on human posture control has been investigated under static conditions, but the effects on dynamic balance have not yet been considered. Objective Investigating the influence of different functional stomatognatic activities (jaw clenching (JAW), tongue pressing (TON) and habitual jaw position (HAB)) on postural performance during a dynamic reactive balance task. Methods Forty-eight physically active and healthy adults were assigned to three groups differing in oral-motor tasks (JAW, TON or HAB). Dynamic reactive balance was assessed by an oscillating platform which was externally perturbed in four directions. Performance was quantified by means of Lehr's damping ratio. Mean speeds of the selected anatomical regions (head, trunk, pelvis, knee and foot) were analysed to determine significant performance differences. Results The groups differed significantly in balance performance in direction F (i.e., forwards acceleration of the platform). Post hoc tests revealed that the JAW group had significantly better performance compared with both the HAB and TON groups. Better performance was associated with a decreased mean speed of the analysed anatomical regions. Conclusion JAW can improve dynamic reactive balance but the occurrence of positive effects seems to be task-specific and not general. TON seems not to have any observable effects on dynamic reactive balance performance, at least when evaluating it with an oscillating platform. JAW might be a valuable strategy which could possibly reduce the risk of falls in elderly people; however, further investigations are still needed.