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Nonlinear Analysis of Dynamic Spine Stability in Healthy and Low Back Pain Patients During Repetitive Flexion Extension Tasks

Moeini Sedeh, Samaneh | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45350 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Arjmand, Navid
  7. Abstract:
  8. Objective: Stability is important to prevent falls during occupational and daily living activities. Control parameters such as speed, direction of motion and external load can affect stability pattern. The purpose of this study was to evaluate the effect of the mentioned control parameters on stability control pattern.
    Methods: Kinematic data (rotation angles) to 19 healthy volunteers and 19 patients with low back pain associated with repeated trunk bending motion in eight different conditions of speed (high and slow), direction (symmetric and asymmetric planes) and external load (with and without load), was evaluated. Since the volunteers do during dynamic movements, they must also be dynamic stability is investigated. It is necessary to note that in various analyzes variability of kinematic data is used as criterion for measuring stability. Because of the nonlinear analyzes quantify the structure or organization of the variations present in a time series, to assess the stability of the system have been appropriate. Two methods for quantifying a system’s dynamic stability have been applied to trunk motion: local stability (quantified by finite time maximum Lyapunov exponents, λ_S and λ_L) and orbital stability (quantified as maximum Floquet multipliers, MF).
    Results: Result of analysis of variance showed that direction, speed and load effects significantly affected maximum Lyapunov exponents and maximum Floquet multipliers. All interaction effects except direction × load and speed × load significantly affected stability criteria used in research.
    Conclusion: In this research maximum Lyapunov exponents and maximum Floquet multipliers methods for quantifying a system’s dynamic stability have been applied to trunk motion. Control parameters such as speed, direction of motion and external load can affect stability pattern and postural control during repetitive trunk bending movment
  9. Keywords:
  10. Dynamic Stability ; Maximum Lyapunov ; Maximum Floauet Multipliers ; Repetive Trunk Bending Movment

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