Mathematical Modeling and Simulation of Seated Stability

Details

• Personal Author:
  Nussbaum MA ; Ross SD ; Tanaka ML
• Description:
  Various methods have been used to quantify the kinematic variability or stability of the human spine. However, each of these methods evaluates dynamic behavior within the stable region of state space. In contrast, our goal was to determine the extent of the stable region. A 2D mathematical model was developed for a human sitting on an unstable seat apparatus (i.e., the "wobble chair"). Forward dynamic simulations were used to compute trajectories based on the initial state. From these trajectories, a scalar field of trajectory divergence was calculated, specifically a finite time Lyapunov exponent (FTLE) field. Theoretically, ridges of local maxima within this field are expected to partition the state space into regions of qualitatively different behavior. We found that ridges formed at the boundary between regions of stability and failure (i.e., falling). The location of the basin of stability found using the FTLE field matched well with the basin of stability determined by an alternative method. In addition, an equilibrium manifold was found, which describes a set of equilibrium configurations that act as a low dimensional attractor in the controlled system. These simulations are a first step in developing a method to locate state space boundaries for torso stability. Identifying these boundaries may provide a framework for assessing factors that contribute to health risks associated with spinal injury and poor balance recovery (e.g., age, fatigue, load/weight, and distribution). Furthermore, an approach is presented that can be adapted to find state space boundaries in other biomechanical applications. [Description provided by NIOSH]
• Subjects:
  Biomechanical Phenomena Environmental Monitoring Musculoskeletal Diseases Musculoskeletal System Nervous System Occupational Health Safety
• Keywords:
  Author Keywords: Basin Of Stability Back-injuries Biodynamics Biomechanical-modeling Biomechanics Environmental-control Environmental-physiology Forward Dynamic Simulation Kinesiology Kinetics Lagrangian Coherent Structures LCS Lyapunov Muscle-contraction Muscle-physiology Muscle-tension Muscles Musculoskeletal-system Physical-reactions Posture Spinal-cord Spinal-cord-disorders Spinal Stability

  More +
• ISSN:
  0021-9290
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  North Carolina ; OSHA Region 3 ; OSHA Region 4 ; Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  43
• Issue:
  5
• NIOSHTIC Number:
  nn:20037008
• Citation:
  J Biomech 2010 Mar; 43(5):906-912
• Contact Point Address:
  Martin L. Tanaka, Department of Orthopaedic Surgery, Wake Forest University, Winston-Salem, NC 27157, USA
• Email:
  mtanaka@wfubmc.edu
• Federal Fiscal Year:
  2010
• NORA Priority Area:
  Services ; Healthcare and Social Assistance
• Performing Organization:
  Virginia Polytechnic Institute and State University
• Peer Reviewed:
  True
• Start Date:
  20060801
• Source Full Name:
  Journal of Biomechanics
• End Date:
  20120731
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1d2724bf4c12cfb42eab0df218cd85659b87179859c3d9b04f2902c1750b6398822506d46193f1b96fb6a0c8ab4fdafed5c6860c2187756d8f2d3bf279eaf2fd
• Download URL:
  https://stacks.cdc.gov/view/cdc/188187/cdc_188187_DS1.pdf
• File Type:
  [PDF - 865.83 KB ]