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1.1 1 xml info:srw/schema/1/mods-v3.2 Liebermann D G author Krasovsky T author Berman S author 2008 English The article characterizes hand paths and speed profiles for movements performed in a nonplanar, 2-dimensional workspace (a hemisphere of constant curvature). The authors assessed endpoint kinematics (i.e., paths and speeds) under the minimum-jerk model assumptions and calculated minimal amplitude paths (geodesics) and the corresponding speed profiles. The authors also calculated hand speeds using the 2/3 power law. They then compared modeled results with the empirical observations. In all, 10 participants moved their hands forward and backward from a common starting position toward 3 targets located within a hemispheric workspace of small or large curvature. Comparisons of modeled observed differences using 2-way RM-ANOVAs showed that movement direction had no clear influence on hand kinetics (p < .05). Workspace curvature affected the hand paths, which seldom followed geodesic lines. Constraining the paths to different curvatures did not affect the hand speed profiles. Minimum-jerk speed profiles closely matched the observations and were superior to those predicted by 2/3 power law (p < .001). The authors conclude that speed and path cannot be unambiguously linked under the minimum-jerk assumption when individuals move the hand in a nonplanar 2-dimensional workspace. In such a case, the hands do not follow geodesic paths, but they preserve the speed profile, regardless of the geometric features of the workspace. Adaptation Physiological Adult Algorithms Female Hand/*physiology Humans *Intention Kinesthesis/*physiology Male Models Statistical Movement/*physiology Psychomotor Performance/*physiology Reference Values Writing PMID:18980905 exported from refbase (https://refbase.nfshost.com/show.php?record=33), last updated on Mon, 31 Dec 2012 14:31:02 +0000 text http://www.ncbi.nlm.nih.gov/pubmed/18980905 http://www.ncbi.nlm.nih.gov/pubmed/18980905 10.3200/JMBR.40.6.516-531 18980905 Liebermann_etal2008 2008 continuing periodical academic journal 40 6 516 531 0022-2895 1