The thesis examined the importance for movement control of perceptual information about the relation of the actor to the environment and about the actor's action capabilities and bodily characteristics. In four experiments it was shown that providing better information improves perceptuo-motor performance in Cerebral Palsied (CP) children. The first two studies investigated whether CP and normal children find abstract tasks more difficult than concrete tasks. CP children were found to perform better on a concrete bang-the-drum-task than on an abstract move-as-far-as-you-can task. The underlying movement kinematics were also different, although the movements involved in both tasks were indistinguishable by eye. Thus, improving information about the CP child's relation to the environment by making a task more concrete improves movement control. The importance of perceiving one's action capabilities was studied in an interceptive timing task in which CP and nursery children were striking an accelerating ball. The results showed that both groups controlled initiation of the striking movements by the value of an optic variable tau specifying time-to-contact under constant velocity (thus treating the accelerating ball as if it was travelling at a constant speed). However, the affected hand of the CP children initiated the striking actions at a significant larger tau value, thus allowing for its relative slowness. The children's striking movements were also analysed in more detail to test a theory of how deceleration and timing of the hand are conjointly controlled.