Setting appropriate timing and force parameters of muscle activity is a significant part of producing skillful movement behavior: Data reported here suggest that an important characteristic of children with developmental coordination disorders (DCD) is inconsistency and lack of precision in regulating timing and force characteristics of muscle activity to correct for perturbations to balance. Children with and without DCD stood on a moveable platform. Balance was perturbed under fully redundant sensory conditions and under conditions where vision was removed or vestibular input was modified. EMG activity in tibialis anterior and quadriceps leg muscles was recorded. Children with normal motor development produced less force than children with DCD. Children with DCD tended to rely on proximal muscle activity to respond to perturbations to balance and, in contrast to children with normal motor development, modified temporal but not force characteristics of muscle activity when the sensory framework for balance was modified.
