Abstract des Autors

Comparisons were made of voluntary movements of the right and left arms in normal human subjects. A series of movmeents of different amplitudes, made at the subject's own speed, was performed with one limb. After a rest period, the same series was repeated with the contralateral limb. The relaiton between movement peak velocity and movement amplitude was lienar and was the same for both arms. With repeated testing ove rperiods up to two months, the slope of the peak velocity - amplitude relation decreased during the first week, thereafter remaining unchanged. In a second series of experiments, six normal subjects continuously wore a 1 Ib (0.45 kg) weight strapped to their left (non-dominant) forearm for up to 1 week. This resulted in an increase in the slope of the peak-velocity/amplitude relaiton in this arm. A parallel change occurred in movements made independently by the right (non-loaded) arm. A similar matching of movement performance of the two limbs was seen following removal of the weight. The data is interpreted as providing support for the hypothesis that there is a single movement "command" which is applied to both limbs. The interaction of this command with the limbs which have similar second-order mechanical properties yields similar movements een when they are made independently. Verf.-Referat