Abstract
In this paper, we analyze human skillful motion in tossing an object. Two different types of motions coexist in this motion: the one is to catch an object softly and the other is to push it up quickly and strongly. We focus on the motions of the wrist and MP joint during this motion and investigate the collaboration of two joints in order to generate smooth and powerful tossing motion. From several experimental results, we can observe the transfer timing of MP joint motion from catching to pushing up is delayed than that of the wrist motion. Due to the delay, the muscle around MP joint is stretched rapidly by the weight of the object and the elastic energy is stored in stretched muscles. In pushing up motion, the release of energy is efficiently used to realize quick and powerful finger motion.
