EMG changes during acquisition of a motor skill.

Currently there are only a few studies which attempt to explain the neuromuscular changes which accompany skilled motor learning. Conflicting results have created the need for further research concerned with the electromyographical correlates of motor skill acquisition. A shuffleboard task was devised that isolated the triceps as the major agonist and the biceps as the major antagonist. Ten undergraduate males enrolled at Iowa State University participated in the study. Multivariate analysis and single degree of freedom components based on polynomial regression were used to test linear, quadratic and cubic trends for eight EMG characteristics plus movement time obtained from a systematic sampling of practice trials. Results indicated that trial period means for movement time, latency period and time to peak activity for the triceps exhibited significant linear trends (negative) during practice. No changes were seen in the integrated electromyograms for either the triceps or biceps. It was concluded that force parameters as measured by integrated EMG activity could be determined very early in the learning process and the distribution of these forces through various aspects of timing characterized learning.