COLLECTIVE VARIABLES IN DYNAMIC POSTURAL STABILITY

Open Access
- Author:
- Dutt-mazumder, Aviroop
- Graduate Program:
- Kinesiology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- November 19, 2015
- Committee Members:
- Karl Maxim Newell, Dissertation Advisor/Co-Advisor
Karl Maxim Newell, Committee Chair/Co-Chair
John Henry Challis, Committee Member
Kristina A Neely, Committee Member
Peter Cm Molenaar, Committee Member - Keywords:
- multi-joint coordination
posture
collective variables
kinematics - Abstract:
- This study investigated aspects of Bernstein's (1967) postulates on the degrees of freedom (dof) problem and the degenerate pathways through which coordination patterns are acquired in skill acquisition. The central focus was an investigation of the proposition that the postural system controls a collective variable to realize the demands of the task. The experimental paradigm used a set of dynamical support bases including a tilted platform (Experiment 1), a sinusoidal translating support surface (Experiment 2), and a ski-simulator (Experiment 3) to address the organization of redundant individual (dof) in the control of upright standing balance tasks. It was hypothesized that the set of experiments would further augment our understanding regarding the mechanisms involved in the control of posture in such dynamic base of support tasks among humans. The collective pattern of findings is consistent with the conclusion that the coupling of center of mass-center of pressure (Experiments 1 and 2) and the coupling of center of mass-platform (Experiment 3) act as a collective variable. This was supported by the faster time scale motions of the joints and their synergies and reflects the structural integrity of the system for dynamic postural stability across the conducted experiments. Furthermore, the center of mass and head reflect independent motions in the postural tasks. The findings reveal that for multi-joint postural tasks, the collective variable adopts two stable coordination patterns in-phase or anti-phase as a function of the scaling of a control parameter.