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 (SDCP(group)) and seven controls [typically developing (TD(group))]. 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 TD(group), 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 SDCP(group), 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.