Control of rapid elbow extension movement.
Normal human subjects made rapid extensions of the elbow from an initial position to visual targets at different angular distances (9 degrees-54 degrees). We recorded joint angle, acceleration, and surface electromyograms (EMGs) with a monopolar electrode from the triceps and the biceps brachii muscles. Both the agonist triceps and antagonist biceps initiated their activation with a slow EMG wave (AGslw and ANTslw). The amplitude of the AGslw increased with angular distance moved, but its duration remained constant. The amplitude of the ANTslw varied among subjects with distance moved. The duration of the ANTslw was approximately constant but more variable than that of the AGslw. The onset of the ANTslw was delayed with increasing movement distance. Our results indicate that movement distance is controlled, at the motoneuron pool level, by the interval of a set of pulses sent to the agonist and antagonist muscles in association with pulse amplitude modulation to the agonist muscle.
Yamazaki
Y
Y
Department of Health and Physical Education, Nagoya Institute of Technology, Japan.
Suzuki
M
M
Mano
T
T
D000328:Adult; D004551:Elbow Joint / Q000294:innervation / Q000502:physiology*; D004576:Electromyography / Q000379:methods; D006801:Humans; D008297:Male; D009043:Motor Activity; D009068:Movement; D009132:Muscles / Q000294:innervation / Q000502:physiology*; D013997:Time Factors