Throwing darts utilizes the interaction torque of the elbow joint

Acquiring the skillful movements of experts is a difficult task in many fields. If we find quantitative indices of skillful movement, we can develop an adaptive training system using the indices. We focused on throwing darts in our previous study. It was found that optimization criteria of sum of squared joint torque changes over time was negatively correlated with subject´s scores, suggesting that the experts optimally controlled the shoulder elevations and rotation around the elbow joint in terms of dynamics. In this study, we investigate the relationship between the skill level of subjects and their utilization joint torque components such as the muscular torque, interaction torque and gravity torque. It is shown found that the sum of squared joint torque components of the subjects correlates with their scores, suggesting that the subjects who can take higher scores utilize the interaction torque of the elbow joint without shoulder displacement.