Abstract
The specific aim of this project was to evaluate how children coordinate movements that combine reaching and whole-body turning. When adults perform turn and reach (T&R) movements, they rotate their torso and extend their arm simultaneously rather than sequentially, generating large Coriolis forces. These Coriolis forces do not degrade reaching movement endpoint accuracy or curvature indicating an adult capacity for context-specific dynamic motor compensation. Our motivation for studying T&R performance in children came from studies showing that such context-specific motor adaptation is a developmental achievement which emerges around the age of eight years. We predicted that children older than eight years would conduct T&R movements simultaneously, like adults, and that younger children would coordinate T&R movements in a sequenced fashion in order to minimize Coriolis force. An alternate prediction was that all children would coordinate T&R movements synchronously and thereby self-generate Coriolis forces but that children older than eight years would reach accurately while younger children would show deviations in their movements correlated with the magnitude of Coriolis force generated. We were unable to obtain results for younger children due to poor tracking data. We found that children 8-12 years old conduct T&R movements in a synchronous fashion and generate Coriolis forces comparable to adults when taking their proportionate size into account. However, their movement curvatures were altered by their selfgenerated Coriolis forces, a result which is not seen in adults. Future studies will improve the recording methodology to explore the developmental patterns of T&R movements in the youngest children.