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[Search of gravity force in the planning of arm pointing movements].

Authors
  • Papaxanthis, C1
  • Pozzo, T
  • 1 Groupe d'Analyse du Mouvement (GAM), UFR STAPS, Université de Bourgogne, Dijon, France. , (France)
Type
Published Article
Journal
Comptes rendus des seances de la Societe de biologie et de ses filiales
Publication Date
Jan 01, 1996
Volume
190
Issue
5-6
Pages
613–619
Identifiers
PMID: 9074726
Source
Medline
Language
French
License
Unknown

Abstract

Arm movements in two directions (downward assisted by gravity and upward against gravity) with three different loads (no load 0.5 and 1 kg) were studied in six subjects. Movements of the arm were recorded using an optoelectronic (2 TV, 100 Hz) system which allowed the computer reconstruction of joint motion. Analyses focused upon finger kinematics in the sagittal plane. Subjects showed curved paths for both directions and load conditions. The path's curvature changed significantly only as a function of the direction of the movement. Velocity profiles were unimodal for all conditions. Upward movements showed greater deceleration than acceleration times in contrast to downward movements which presented more symmetrical velocity profiles. The ratio of acceleration time to total movement time changed significantly only as a function of the direction of the movement but not as a function of the load. Results from this study provide indirect evidence that the CNS executes movements by taking advantage of gravity force.

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