Biomechanics and Electromyography of a Cumulative Lumbar Disorder: Response to Static Flexion

Details

• Personal Author:
  Baratta RV ; Burger E ; Solomonow M ; Zhou BH
• Description:
  To assess the mechanical and neurological processes active in the development of a cumulative trauma disorder (CTD) associated with repetitive exposure to periods of static lumbar flexion. The spine of the feline model was subjected to a series of three 10 min sessions of static lumbar flexion with each session followed by a 10 min rest. A 7 h rest period was implemented after the series of three flexion-rest sessions while monitoring viscoelastic (disks, ligaments, etc.) creep and multifidus EMG. A model was fitted to the experimental data from the flexion-rest period and the 7 h recovery period. The creep developed in each 10 min static flexion period did not fully recovery during the following 10 min rest, resulting in a large cumulative creep at the end of the flexion-rest period. The cumulative creep did not fully recover over the following 7 h rest period. A neuromuscular disorder consisting of reduced muscular activity superimposed by spasms during static flexion periods and hyperexcitability during the 7 h recovery was evident. Comparison of the data to previous tests of continuous static flexion for 20 min reveal that the neuromuscular disorder elicited by the series of three 10 min flexion-rest was substantially attenuated when compared to a single 20 min static flexion although the overall work time was 50% larger. Frequent rest periods are highly beneficial in attenuating the development of a CTD, yet not able to prevent it, as viscoelastic tissues residual creep accumulates and its recovery is of extremely long duration. The data provides direct biomechanical and physiological evidence that explain the development of a CTD due to prolonged exposure to static lumbar flexion as well as confirms the epidemiological data correlating such work conditions with substantial increase in symptoms of low back disorders. The benefit of frequent rest periods in attenuating the risk of such a disorder is validated as an effective intervention. [Description provided by NIOSH]
• Subjects:
  Animals Biomechanical Phenomena Cumulative Trauma Disorders Epidemiology Musculoskeletal Diseases Musculoskeletal System Occupational Health Safety
• Keywords:
  Animal Studies Back Injuries Biomechanics Cumulative Trauma Disorders Neuromuscular System Disorders Rest Periods Spasms
• ISSN:
  0268-0033
• 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
• Volume:
  18
• Issue:
  10
• NIOSHTIC Number:
  nn:20029246
• Citation:
  Clin Biomech 2003 Dec; 18(10):890-898
• Contact Point Address:
  Occupational Medicine Research Center, Bioengineering Laboratory, Department of Orthopaedic Surgery, Louisiana State University Health Sciences Center, 2025 Gravier Street--Suite 400, New Orleans, LA 70112, USA
• Email:
  msolom@lsuhsc.edu
• Federal Fiscal Year:
  2004
• 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:
  Clinical Biomechanics
• End Date:
  20031030
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:d21403ff335d68a4bbb8e2f2835cbe71ba75fb3d0d5f34174d7d79916267f12d1d524cc35f5126a3f0ef754f146c5234b131fe880c8e916f4ba40f3b59e8061e
• Download URL:
  https://stacks.cdc.gov/view/cdc/190278/cdc_190278_DS1.pdf
• File Type:
  [PDF - 334.49 KB ]