Speaker
Description
Research on human motor behavior has extensively investigated the kinematics of both upper and lower limb. However, these two districts where often considered separately. Consequently, while it is well known that movements performed with either arms or legs exhibit highly variable motor implementation, the study of their potential covariation effects remains basically neglected. To fill this gap, a combined analysis of motor variability of the upper and lower limb was carried out. 16 healthy subjects completed a pointing task, vertical extensions of the dominant arm, and self-paced walking on dual-belt treadmill, while kinematics was recorded through optoelectronic cameras. Upper limb movement was described through shoulder elevation angle, angular velocities of flexion/extension of the elbow, and angular velocities of flexion/extension of the wrist. Lower limb movement was described through the angular velocities of flexion/extension of the hips, knees and ankles. The Procrustes transformation was then used to compute distance between movements (separately for upper and lower limb), and results served as input for (two separate) 2-dimensional Multidimensional scaling. Finally, the space of variability of each subject was quantified as the amount of the bi-dimensional space covered by the executed movements, separately for the limbs, and enclosed by an ellipse. Results indicate positive correlation effect (p<0.05) between the space of variability measured for the upper and the lower limb of each subject. These results may indicate the presence of common sources of variability both for upper and lower limb movements, in turn providing support for the existence of coherent individual motor fingerprint.
