Three-dimensional drawings in isometric conditions: relation between geometry and kinematics

Exp Brain Res. 1992;88(3):685-90. doi: 10.1007/BF00228198.


Normal human subjects grasped a 3-D isometric handle with an otherwise unrestrained, pronated hand and exerted forces continuously to draw circles, ellipses and lemniscates (figure-eights) in specified planes in the presence or absence of a 3-D visual force-feedback cursor and a visual template. Under any of these conditions and in all subjects, a significant positive correlation was observed between the instantaneous curvature and angular velocity, and between the instantaneous radius of curvature and tangential velocity; that is, when the force trajectory was most curved, the tangential velocity was lowest. This finding is similar to that obtained by Viviani and Terzuolo (1982) for 2-D drawing arm movements and supports the notion that central constraints give rise to the relation between geometric and kinematic parameters of the trajectory.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Female
  • Forearm / physiology
  • Hand / physiology
  • Humans
  • Isometric Contraction*
  • Male
  • Mathematics*
  • Models, Biological*
  • Movement
  • Muscles / physiology
  • Reference Values