Change scores will be calculated for each subject to determine an Index of Improvement (IP) and an Index of Learning (IL). The IP is defined as the change in each variable as a ratio of post- to pre-test values. An IP of 1 indicates no change whereas negative and positive values indicate that the value decreased or increased respectively. For some variables, positive ratios will indicate improvement (endpoint velocity, endpoint smoothness, angle measures, phase amplitudes) while for others, improvement will be demonstrated by negative ratios (movement time, movement precision). The IL, used to determine if subjects retain improvements after training for each follow-up epoch, is defined as the change in the variable at retention- compared to post-test. IL values of 1 indicate that the improvement is maintained (no change), of negative value that the parameter decreased and of positive value that the parameter increased.