Examining procedural consolidation with visuomotor learning in the lower limb.

To investigate the effects of interference tasks in the early stages of motor learning, we used a computerized motor skill analyzer (CMSA) for the lower limb that evaluates the accuracy and speed of movements in tracking tasks. Forty-five healthy subjects were randomly divided into three groups: a control group without an interference task, a mirror image interference group, and a point symmetry interference group. The practice and measurement of motor-learning trials were carried out as follows: (1) 10 practice trials followed by 10 measurement trials in the morning of the first day. (2) 10 measurement trials 6-7 awake hours after the first measurement. (3) 10 measurement trials on the morning of day 2. In the learning interference groups, 10 trials of the mirror image or point symmetry task were performed immediately after the first measurement. Although motor skills of the control group improved, those of the learning interference groups did not. This suggests that a second task performed immediately after the first task interferes with the consolidation of motor skill learning demanding complex visuomotor transformation.