Do axes of rotation change during fast and slow motions of the dominant and non-dominate arms?

^(*) Univ. Paris-Sud. URCIAMS – Motor Control & Perception team, Orsay F-91405, France
^(†) Univ. du Sud – Toulon Var, HandiBio, EA 4322, La Garde F-83957, France
^(‡) Clemson Univ. Department of Psychology, Clemson, SC 29634, USA
E-mail: Clint.Hansen@u-psud.fr, rezzoug@univ-tln.fr, gorce@univ-tln.fr

Abstract

The velocity-dependent change in rotational axes observed in the control of unconstrained 3D arm rotations for the dominant limb seems to conform to a minimum inertia resistance (MIR) principle [4]. This is an efficient biomechanical solution that allows for the reduction of torques. We tested whether the MIR principle governs rotating movement when subjects were instructed to maintain the shoulder-elbow joint axis close to horizontal for both dominant and non dominant limbs. Subjects (n=12) performed externalinternal rotations of their arms in two angular positions (90° versus 150°), two angular velocities (slow (S) versus fast (F)), and in two sensory conditions (kinaesthetic (K) versus visuo- kinaesthetic (VK)). We expected more scattered displacements of the rotation axis employed for rotating the non dominant limb compared to the dominant limb. The results showed that the rotational axis of a multiarticulated limb coincided with SH-EL at S & F velocity for both arms.