Relationship between visual and iinesthetic imagery, field dependence-independence, and complex motor skills

Visual imagery (VI) involves self-visualization of action, whereas kinesthetic imagery (KI) implies somesthetic sensations elicited by action. Motor imagery (MI) has been shown to enhance motor performance but inconsistent results were obtained depending on the respective impacts of VI and KI. It is hypothesized here that the type of MI may interact with individual characteristics such as field dependence-independence. As subjects' movements can be mainly checked out through exteroceptive or proprioceptive information, task requirements were also expected to influence MI. Witkin's Group Embedded Figures Test was implemented with two groups (n(1) = 10 gymnasts, n(2) = 10 tennis players). Athletes were asked to imagine a complex motor skill by alternate use of VI and KI. Skin resistance was selected as a peripheral indicator of MI and recorded continuously. Autonomic responses were compared by computing the VI/KI ratio. Results taking both the field-dependence test and MI type into account were not as clear as expected. As hypothesized, gymnasts were more field-independent than tennis players. VI/KI ratio analysis showed that a similar pattern was observed in the gymnasts group (ratio close to 1.0), whatever the type of imagery. This suggests that gymnasts are equally able to perform VI and KI. Fifty percent of the tennis players group showed a ratio higher than 1.0, suggesting that VI was more effective than KI. Conversely, the remaining 50% showed a below-1.0 ratio, suggesting more effective KI. Thus, some tennis players may make better use of VI than KI, and conversely some may make better use of KI than VI. These results indicate that MI training may be relatively independent of task requirements and be based mainly upon individual characteristics such as MI abilities. Finally, results indicate systematic overestimation in self-estimation of movement duration during MI, which was greater during KI than during VI, suggesting that athletes have greater trouble in feeling than in visualizing movement.