Body alignment and postural muscle activity at quiet standing and anteroposterior stability limits in children with spastic diplegic cerebral palsy

Purpose. We investigated body alignment and muscle activity at quiet standing and anteroposterior stability limits in children with spastic diplegic cerebral palsy (SDCP). Method. Body alignment and electromyographic (EMG) activity of ventral and dorsal lower limb muscles at three different standing positions were compared between seven children with SDCP (SDCPgroup) and seven controls [typically developing (TDgroup)]. We also compared these measurements in a child with SDCP before and after a 3-week training in which the child leant forward and maintained the forward-leaning posture with the help of a physiotherapist who manually held her lower limbs fixed in position. Results. In TDgroup, EMG activity of the dorsal muscles increased at the extreme forward-leaning position, whereas that of the ventral muscles increased at the extreme backward-leaning position. In SDCPgroup, such direction-specific increases were observed in lower leg muscles but not in thigh muscles. As a result of training, direction-specific activity in the dorsal muscles improved, and crouch posture was also improved. Conclusions. Our findings suggest that children with SDCP have difficulty modulating muscle activity while standing and that the quadriceps plays a critical role in maintaining couch posture. In addition, crouch posture may be improved by the training which focuses on control of the dorsal muscles.