- A forced arm exercise was investigated as a means of eliminating head-hitting in two children. During sessions restraints used to manage subjects were removed. After a baseline measure, required practice of repeated vertical arm movements was made contingent upon each response. Later, this procedure was combined with reinforcement under a differential reinforcement of other behavior schedule. Arm exercise alone produced a substantial decrease in head-hitting, while the combination treatment engendered near-zero levels. Subsequently, reduction of head-hitting was extended to several contexts by regular ward staff. This type of treatment appears as effective with self-injurious behavior as it is with stereotyped behavior.