Modeling movements of a long hand-held tool with effects of moments of inertia

The current experiment aimed to investigate the effects of weight position on movement time in target acquisition tasks. Subsequently, a simple mathematical model was developed to describe the movement time with the moments of inertia. Ten right-handed participants conducted continuous Fitts pointing tasks using a laparoscopic instrument as a long hand-held tool. The results showed significant effects of weight position on movement time. Furthermore, an extended Fitts’ law model is proposed for the moments of inertia produced by the hand, instrument, and a constant mass in different positions. This predictive model accounted for 63% of the variance in movement time. The predictive model proposed in the present study can be applied not only to estimate movement time given a particular target width, instrument movement amplitude, and weight position of a long hand-held tool but also to standardize movement time and establish training standards.