The role of trait anxiety on static balance performance in control and anxiogenic situations.

Recent studies have highlighted interactions between state anxiety, sensory processing involved in motor performance, and personality traits such as trait anxiety. In the present study, we investigated the effects of moderate state anxiety on static balance performance with eyes open and eyes closed in two groups of healthy subjects with contrasting trait anxiety. We found that an anxiogenic condition induces larger and faster body swaying in both groups in the eyes-open test. This suggests that state anxiety could modify the processing of the different sensory inputs involved in balance control whatever the subjects' trait anxiety level. When vision is absent, precision of static balance control in individuals with intermediate level of trait anxiety - characterized by a higher visual dependence - is more disrupted than in low trait anxiety subjects. Moreover, moderate state anxiety seems to disturb the ability to use vestibular and/or somatosensory inputs in individuals with low anxiety, but not in individuals with intermediate trait anxiety. These results on inter-individual differences provide a first insight into the inter-dependence between trait anxiety, state anxiety and static balance control.