Muscular Dysfunction Elicited by Creep of Lumbar Viscoelastic Tissue

Details

• Personal Author:
  Baratta RV ; Burger E ; Gedalia A ; Solomonow M ; Zhou BH ; Zieske A
• Description:
  The biomechanics, histology and electromyography of the lumbar viscoelastic tissues and multifidus muscles of the in vivo feline were investigated during 20 min of static as well as cyclic flexion under load control and during 7 h of rest following the flexion. It was shown that the creep developed in the viscoelastic tissues during the 20 min of static or cyclic flexion did not fully recover over the 7 h of following rest. It was further seen that a neuromuscular disorder with five distinct components developed during and after the static and cyclic flexion. The neuromuscular disorder consisted of a decreasing magnitude of reflexive EMG from the multifidus upon flexion as well as of superimposed spasms. The recovery period was characterized by an initial muscle hyperexcitability, a slowly increasing reflexive EMG and a delayed hyperexcitability. Histological data from the supraspinous ligament demonstrate significant increase (x 10) in neutrophil density in the ligament 2 h into the recovery and even larger increase (x 100) 6 h into the recovery from the 20 min flexion, indicating an acute soft tissue inflammation. It was concluded that sustained static or cyclic loading of lumbar viscoelastic tissues may cause micro-damage in the collagen structure, which in turn reflexively elicit spasms in the multifidus as well as hyperexcitability early in the recovery when the majority of the creep recovers. The micro-damage, however, results in the time dependent development of inflammation. In all cases, the spasms, initial and delayed hyperexcitabilities represent increased muscular forces applied across the intervertebral joints in an attempt to limit the range of motion and unload the viscoelastic tissues in order to prevent further damage and to promote healing. It is suggested that a significant insight is gained as to the development and implications of a common idiopathic low back disorder as well as to the development of cumulative trauma disorders. [Description provided by NIOSH]
• Subjects:
  Manufacturing And Industrial Facilities Mining Occupational Health Safety
• Keywords:
  Animal-studies Animals Back-injuries In-vivo-study Laboratory-animals Muscles Muscular-disorders Musculoskeletal-system Musculoskeletal-system-disorders Spasms Spinal-cord Tension

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• ISSN:
  1050-6411
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Louisiana ; OSHA Region 6
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  381-396
• Volume:
  13
• Issue:
  4
• NIOSHTIC Number:
  nn:20024549
• Citation:
  J Electromyogr Kinesiol 2003 Aug; 13(4):381-396
• Contact Point Address:
  Moshe Solomonow, Bioengineering Laboratory, Occupational Medicine Research Center, Department of Orthopaedic Surgery, Louisiana State University Health Sciences Center, 2025 Gravier Street, Suite 400, New Orleans, Louisiana 70112, USA
• Email:
  msolom@lsuhsc.edu
• Federal Fiscal Year:
  2003
• NORA Priority Area:
  Disease and Injury: Low Back Disorders
• Performing Organization:
  Louisiana State University, Health Sciences Center, New Orleans, Louisiana
• Peer Reviewed:
  True
• Start Date:
  20000501
• Source Full Name:
  Journal of Electromyography and Kinesiology
• End Date:
  20031030
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:4d7dfbec5e956259fa6a2a700097be7df5b1baa2559ad9293a6daaa4ffdabc8c8b3d66b7f5a5d458175ab2d7c2ee6afe38a868f6faa97372dbc5ff9fcb47ff2d
• Download URL:
  https://stacks.cdc.gov/view/cdc/196309/cdc_196309_DS1.pdf
• File Type:
  [PDF - 631.77 KB ]