Influence of vision and motor imagery styles on equilibrium control during whole-body rotations.

To investigate the influence of vision and motor imagery styles on equilibrium control, displacements of the supporting foot during spontaneous whole-body rotations ("pirouette") by expert female ballet dancers were analyzed using three-dimensional kinematics. Four turn types were defined according to direction (clockwise, CW vs. counterclockwise, CCW) and supporting foot (SF, left vs. right). Visual influences were examined by including two visual conditions (blindfolded vs. full-vision). Motor imagery styles were determined using the Vividness of Movement Imagery Questionnaire (VMIQ) (Kinesthetic, n = 4 vs. Visual/Kinesthetic, n = 6). Turning direction preference was assessed by a closed-response questionnaire in which all dancers indicated that they preferred CW turn direction. Kinesthetic dancers showed more SF displacement during CCW (non-preferred direction) than CW (preferred direction) pirouettes. However, Visual/Kinesthetic dancers showed no significant effect of turn direction. Furthermore, Kinesthetic dancers showed no significant effect of vision on SF displacement whereas Visual/Kinesthetic dancers showed significantly higher SF displacement when vision was occluded. Thus there appears to be a selective effect of vision on Visual/Kinesthetic dancers, and a selective effect of turn direction on Kinesthetic dancers. These results suggest that perceptual styles should be taken into consideration when training tasks that require fine equilibrium control because the factors that perturb balance differ depending on perceptual style.