A modified version of Fog’s clip-pinching task developed by Todor and Lazarus (1986) was used to assess associated movement or motor overflow in children with and without learning disabilities (LD). Children with LD as a group displayed greater overflow at all levels of active limb force than their age-equivalent nondisabled peers. Children with LD who also have attention deficit hyperactivity disorder were variable in their ability to consciously inhibit overflow while children with LD without attention deficit hyperactivity disorder were able to override overflow given verbal cues to do so. Results indicate that children with LD, as a group, tend to be more affected by the force output requirement of this task due to other factors such as attention and inhibition that differ in degree from nondisabled age-matched control subjects, or at least that persist for a longer period of time in development. The degree to which the regulation of attention interacts with the regulation of force differs for the two subgroups of children with LD, those with and without attention deficit hyperactivity disorder.
Jo-Anne C. Lazarus is with the Department of Kinesiology, University of Wisconsin–Madison, 2000 Observatory Dr., Madison, WI 53706.