The proposed research represents a systematic and controlled investigation of electromyographic feedback in motor learning. Studies are reviewed that suggest that training procedures which use audio and visual display of electromyographic signals to augment sensory feedback from skeletal muscles lead to improved voluntary control of skeletal muscle responses, both in normal individuals and in persons with motor dysfunction. The studies reported to date, however, have seldom gone beyond the simple demonstration of an effect to a detailed examination of the learning processes involved. Studies are proposed investigating the specific effects of EMG feedback, those directly attributable to the provision of electromyographically augmented feedback during learning, on the acquistion of skeletal muscle responses. These studies employ normal human subjects working with an unfamiliar and poorly controlled muscle, and also subjects with residual motor dysfunction subsequent to central system damage. An additional study with normal subjects examines the effects of schedule of EMG feedback presentation on the acquisition of a motor response and on transfer of training to the non-feedback condition. A final study with normal subjects assesses the relative effects of information and incentive on the acquistion of a skeletal muscle response. Studies such as these which question the nature and extent of currently reported feedback-related effects are essential for the development of treatment procedures which are both clinically effective and scientifically sound.