The Effect of Training and Handedness on the Performance of Two Simple Motor Tasks

Abstract

In the first experimental series nine right-handed and nine left-handed subjects were tested on each side on two tasks. The first task measured the accuracy of reproduction of pressure in attempted extension of the elbow joint, and the second the speed of oscillation of attempted flexion and extension of the elbow joint. The results showed no significant difference in performance on the two sides in the accuracy task but a significant difference in performance on the speed task. In the second experimental series the effect of 15-minutes daily training on each of two tasks over a four-week period was investigated on six subjects. The two tasks were the same as those used in the first experimental series, and attempted movement at the metacarpo-phalangeal joint as well as the elbow joint was studied. The mean results of all subjects showed a significant reduction in the mean error of the “accuracy” task over the training period for both the finger and arm. However, further analysis suggests that this may have been due to a clarifying of the subjects’ concept of the target value rather than an improvement in his ability to grade the appropriate muscle contractions. A significant increase in the mean speed of oscillation over the training period was also recorded for both finger and arm. This improvement was accompanied in most instances by a corresponding decrease in variation of cycle length of the individual oscillations, which is interpreted as an improvement in the subjects’ “timing” of the appropriate muscle contractions.