Reduction of muscle activity during repeated reach and retrieval with gravity compensation in stroke patients

Active movement of the affected arm is important in the training of arm function after stroke. By supporting the weight of the arm during movements, either in conventional treatment or in other approaches such as robot-aided therapy, active arm movements can be facilitated. Studies into the influence of arm support display encouraging results for its use in post-stroke arm rehabilitation. The objective of the present study was to investigate the influence of gravity compensation on muscle activity during reach and retrieval movements of stroke patients. Eight stroke patients performed repeated reach and retrieval movements with and without gravity compensation. Comparison of muscle activity of shoulder and elbow muscles in both conditions showed that the level of muscle activity was reduced with gravity compensation, while movement execution was comparable. This implies that gravity compensation may facilitate active use of the arm during post-stroke rehabilitation.