title: Postural adaptation during arm raising in children with and without unilateral cerebral palsy.
abstract: Postural sway during arm movements were related to the size of the base of support (BOS) and the limits of stability (LOS) of children with unilateral cerebral palsy (USCP) and typically developing (TD) children. For half of the trials the mechanical disturbance due to the rapid arm movement was increased by attaching small weights at the wrists. The participants stood with both feet on a large force plate, which recorded the displacements of the center of pressure (CoP). The results showed that in the children with USCP the LOS forward and toward the non-dominant (more-affected) side were smaller than in the TD children whereas the LOS backward and toward the dominant (less-affected) side did not differ between the two groups. When rapidly moving the arms the children with USCP swayed over a larger portion of their base of support in the forward direction and toward their more-affected side. In addition, the maximal sway toward the more-affected side during arm movement exceeded the LOS while balance was maintained. These effects increased when the movements were performed with the weights at the wrists. These results show that an area of permissible sway, which was not spontaneously explored during the leaning task, was required to maintain balance during the supra-postural task. Training to enlarge the LOS that includes weight shifts toward the more-affected side might reduce the area of the BOS that is self-perceived as less secure.
authors.affiliation: Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, Van Der Boechorststraat 9, Amsterdam 1081 BT, The Netherlands. Electronic address: a.ledebt@vu.nl.
authors.forename: Annick
authors.initials: A
authors.lastname: Ledebt
authors.affiliation: Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, Van Der Boechorststraat 9, Amsterdam 1081 BT, The Netherlands.
authors.forename: Geert J P
authors.initials: GJ
authors.lastname: Savelsbergh
mesh_terms: D002547:Cerebral Palsy / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009043:Motor Activity; D009048:Motor Skills; D010291:Paresis / Q000175:diagnosis; D004856:Postural Balance; D011187:Posture; D012016:Reference Values; D016474:Weight-Bearing
keywords: Balance; Base of support; Center of pressure; Congenital hemiparesis; Limits of stability; Postural adjustments