title: Effects of biomechanical and task constraints on the organization of movement in precision aiming.
abstract: Nine participants performed a reciprocal precision aiming task under different experimental conditions. Due to the anisotropy of the work space, varying the direction of motion (from 0 degrees to 315 degrees in steps of 45 degrees ) allowed exploration of the effects of biomechanical constraints that were found to affect the duration of movement but not the shape of the kinematic pattern. Varying the size of the targets to be attained (W: 2.5, 1.25, and 0.625 cm, for a constant intertarget distance of 10 cm) and the nature (linear or non-linear) of the mapping between effector space (motion of a handheld stylus on a graphics tablet) and task space (motion of a pointer between targets on a computer screen) also led to changes in movement duration. However, the latter type of constraint gave rise to systematic changes in the pattern of movement, with progressively more difficult tasks being characterized by progressively less harmonic motion patterns. We conclude that in contrast to (biomechanical) constraints at the level of the effector, (informational) constraints at the level of the task affect the processes underlying movement organization. For the range of values studied, the effects of these two types of constraint can be considered to be independent.
authors.affiliation: UMR 6152 Mouvement and Perception, University of the Mediterranean and CNRS, 163 avenue de Luminy--CP 910, 13288 Marseille cédex 09, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Fernandez
authors.forename: Reinoud J
authors.initials: RJ
authors.lastname: Bootsma
mesh_terms: D000328:Adult; D000465:Algorithms; D016880:Anisotropy; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009068:Movement / Q000502:physiology*; D009949:Orientation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013028:Space Perception / Q000502:physiology