Open Access
Kim, Sun
Graduate Program:
Master of Science
Document Type:
Master Thesis
Date of Defense:
November 19, 2008
Committee Members:
  • Mark L, Latash, Thesis Advisor
  • Mark Latash, Thesis Advisor
  • Finger Force Enslaving Kinetics Kinematics
The main goal of this dissertation has been to study the inter-dependence between actions of the fingers of the human hand. Earlier studies quantified finger inter-dependence in either isometric conditions using force production tasks, or in nearly isotonic conditions using finger movement tasks. We addressed a common situation when a person holds an object using a subset of the digits of the hand and moves one of the digits. Participants moved one of the fingers (task finger) of the right hand trying to follow a cyclic, ramp-like flexion-extension template at different frequencies. The other fingers (non-task fingers) were restricted from moving; their fingertip pressing forces were recorded and analyzed. The index finger motion caused the smallest force production by the non-task fingers. Larger forces were produced by the neighbors of the task finger; these forces showed strong modulation over the range of motion of the task finger. The forces were higher during the flexion phase of the movement cycle as compared to the extension phase. The index of enslaving expressed in N/rad depended on the movement speed and was higher when the task finger moved through the more flexed postures. These observations suggest an important role of central, neural mechanisms in the patterns of finger interdependence. They also suggest that methods of analysis of finger coordination based on an assumption of universal matrices of finger interdependence should consider the specific features of the studied tasks.