Effects of task complexity on coordination of inter-limb and within-limb forces in static bimanual manipulation

Motor Control. 2010 Oct;14(4):528-44. doi: 10.1123/mcj.14.4.528.

Abstract

Coordination of the hand grip (G; acting normally to the grasping surface) and load forces (L; acting in parallel) in bimanual static tasks was studied. L symmetry (either the magnitude or direction) and frequency were manipulated in healthy participants (N = 14). More complex tasks (i.e., the higher frequency and/or asymmetric ones) revealed expected deterioration in both the task performance (accuracy of the prescribed L force profiles) and force coordination (G/L ratio and G-L correlation) suggesting importance of L frequency and symmetry in prehension activities. However, the same tasks revealed a more prominent deterioration of interlimb than the within-limb force coordination. This could be interpreted by two partly different and noncompeting neural control mechanisms where the coordination of interlimb forces may be based on ad-hoc and task-specific muscle coordination (often referred to as muscle synergies) while the within-limb coordination of G and L could be based on more stable and partly reflex mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Female
  • Hand Strength / physiology*
  • Humans
  • Male
  • Motor Activity / physiology*
  • Motor Skills / physiology*
  • Muscle Contraction / physiology*
  • Weight-Bearing / physiology