Fatigue Influences the Dynamic Stability of the Torso

Details

• Personal Author:
  Gottipati P ; Granata KP
• Description:
  Fatigue in the extensor muscles of the torso affects neuromuscular recruitment and control of the spine. The goal of this study was to test whether fatigue influences stability of dynamic torso movements. A controlled laboratory experiment measured the change in the maximum finite-time Lyapunov exponent, lambda(max), before and after fatigue of the extensor muscles. Non-linear analyses were used to compute stability from the embedding dimension and Lyapunov exponent recorded during repetitive dynamic trunk flexion tasks. Torso extensor muscles were fatigued to 60% of their unfatigued isometric maximum voluntary exertion force then stability was re-measured. Independent variables included fatigue, task asymmetry and lower-limb constraint. lambda(max) values increased with fatigue suggesting poorer dynamic stability when fatigued. Embedding dimension declined with fatigue indicating reduced dynamic complexity when fatigued. Fatigue-related changes in spinal stability may contribute to the risk of low-back injury during fatiguing occupational lifting tasks. The findings reported here indicate that one mechanism by which fatigue contributes to low back disorders may be spinal instability. This information may contribute to the development of ergonomic countermeasures to help prevent low back disorders. [Description provided by NIOSH]
• Subjects:
  Mining Occupational Health Safety
• Keywords:
  Back-injuries Biodynamics Biological-function Biomechanical-modeling Biomechanics Ergonomics Fatigue Fatigue-properties Mathematical-models Muscle-contraction Muscle-physiology Muscle-tension Muscles Musculoskeletal-system Physiological-factors Physiological-fatigue Physiological-stress Physiological-testing Physiology Posture Qualitative-analysis Risk-analysis Risk-factors Spinal-cord Spinal-cord-disorders Statistical-analysis

  More +
• ISSN:
  0014-0139
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  51
• Issue:
  8
• NIOSHTIC Number:
  nn:20034639
• Citation:
  Ergonomics 2008 Aug; 51(8):1258-1271
• Contact Point Address:
  The Kevin P Granata Musculoskeletal Biomechanics Laboratory, Department of Mechanical Engineering, School of Biomedical Engineering and Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
• Federal Fiscal Year:
  2008
• NORA Priority Area:
  Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
• Performing Organization:
  Virginia Polytechnic Institute and State University
• Peer Reviewed:
  True
• Start Date:
  20010930
• Source Full Name:
  Ergonomics
• End Date:
  20050929
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:0f0e604996f828b40e5ff8319c6824b83146afd96782bcb6d33d41e2efc9ffe5d3e9bac8ee4a9cce46824bb7c144d2a1987e36595e82127b350929e637370d0e
• Download URL:
  https://stacks.cdc.gov/view/cdc/186776/cdc_186776_DS1.pdf
• File Type:
  [PDF - 953.68 KB ]