Activation of the Shoulder Belt and Shoulder Muscles of Humans Related to Different Rates of Generation of Two-Joint Efforts by the Forearm

摘要: We studied coordination of central motor commands (CMCs) coming to the muscles that flex and extend shoulder elbow joints in course generation voluntary isometric efforts different directions by forearm. Dependences characteristics these on direction effort rate its were analyzed. Amplitudes rectified averaged EMGs recorded from a number belt considered correlates CMC intensity. The development given rise was realized horizontal-plane operational space; arm position corresponded 30 deg angle joint (external with respect frontal plane) 90 joint. plotted sector diagrams relative changes level dynamic stationary phases EMG activity for entire set generated rates rise. In formation rapid two-joint efforts, realization nonsynergic tasks (extension one flexion another one, vice versa) required significant activation functional both joints. Time organization extensors flexors related maximum relatively (rise time 0.12 0.13 0.25 sec, respectively) rather complex included phases. With parameters (both extension), appearance at 40 N controlled based coordinated interaction agonistic antagonistic muscles. It is concluded CMCs upon are similar their those under conditions forearm movements space an isotonic mode.