Limb-Segment Selection in Graphic Movements: Part 1: A Space-Domain Analysis

摘要

The paper examines how people select specific combinations of limb segments tocarry out physical tasks. Four determinants of limb-segment selection are hypothesized. First, it is recognized that the range of motion which a limb segment can achieve delimits the range of amplitudes for which it can be used. Second, it is argued that each limb segment has an optimal movement amplitude and frequency which can be attributed to its length and mass. Third, it is reasoned that joint characteristics restrict the number of directions in which limb segments can be moved. Finally, a non-anatomical factor is considered, viz., hysteresis, which results from a tendency to maintain the use of an already recruited limb-segment pattern over time. It reports an experiment in which the selection of limb segments is investigated in a graphic task. It is concluded that limb-segment coordination is adaptively related to (1) anatomical features of the motor system, i.e., the size and inertia of limb segments and joint characteristics, and (2) an economic principle which minimizes the selection of new limb-segment patterns. It discusses the scope of the findings in view of the literature on graphic movement coordination.