ABSTRACT
Arm movements are obviously influenced by kinematic requirements. For example, reaching and pointing movements generally rely on visual information about the three-dimensional, spatial location of the target. The free kinematic variables of a reaching movement seem to be specified at least partially as an outcome of the optimization of dynamic kinetic factors. Thus although it is clear that reaching is a spatially-defined kinematic problem, the fundamental algorithm of neural control appears to be significantly influenced by the optimal dynamic kinetic solution. The experimental paradigm provided a general test of the existence of a Donders’ law for reaching movements. Historically, Hollerbach and colleagues were among the first investigators to break away from the experimental focus on either kinematic or quasi-static control algorithms, and to highlight the distinction between quasi-static and dynamic torques. These investigators described the kinetic scaling algorithm that would be necessary to achieve the observed kinematic scaling of the typical “bell-shaped” velocity profile.
