Impact of Muscle Length During Stretch-Shortening Contractions on Real-Time and Temporal Muscle Performance Measures in Rats In Vivo

Details

• Personal Author:
  Baker BA ; Cutlip, Robert G. ; Geronilla KB ; Kashon ML ; Miller, G. Roger ; Schopper AW
• Description:
  The objective of the present study was to investigate the impact of muscle length during stretch-shortening cycles on static and dynamic muscle performance. Animals were randomly assigned to an isometric (control, Con, n = 12), a short-muscle-length (S-Inj, 1.22-2.09 rad, n = 12), or a long-muscle-length (L-Inj, 1.57-2.44 rad, n = 12) group. The dorsiflexor muscles were exposed in vivo to 7 sets of 10 stretch-shortening contractions (conducted at 8.72 rad/s) or 7 sets of isometric contractions of the same stimulation duration by using a custom-designed dynamometer. Performance was characterized by multipositional isometric exertions and positive, negative, and net work before exposure, 6 h after exposure, and 48 h after exposure to contractions. Real-time muscle performance during the stretch-shortening cycles was characterized by stretch-shortening parameters and negative, positive, and net work. The S-Inj group recovery (force difference) was similar to the Con group force difference at 48 h, whereas the L-Inj group force difference was statistically greater at 1.39, 1.57, and 1.74 rad than the Con group force difference (P < 0.05). Negative work (P < 0.05) and net work (P < 0.05) were statistically lower in the S-Inj and L-Inj groups than in the Con group 48 h after exposure to contractions. Of the real-time parameters, there was a difference in cyclic force with treatment during the stretch-shortening cycles (P < 0.0001), with the L-Inj group being the most affected. Thus longer ranges of motion result in a more profound isometric force decrement 48 h after exposure to contractions and in real-time changes in eccentric forces. [Description provided by NIOSH]
• Subjects:
  Animals Laboratories Musculoskeletal System Occupational Exposure Occupational Health Safety
• Keywords:
  Animal-studies In-vivo-studies Injuries Laboratory-animals Muscle-contraction Muscle-tension Muscles Occupational-exposure Simulation-methods
• ISSN:
  8750-7587
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  96
• Issue:
  2
• NIOSHTIC Number:
  nn:20024742
• Citation:
  J Appl Physiol 2004 Feb; 96(2):507-516
• Contact Point Address:
  R. G. Cutlip, National Institute for Occupational Safety and Health, Health Effects Laboratory Division, 1095 Don Nehlen Dr., M/S 2027, Morgantown, WV 26505
• Email:
  rgc8@cdc.gov
• Federal Fiscal Year:
  2004
• NORA Priority Area:
  Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
• Peer Reviewed:
  True
• Source Full Name:
  Journal of Applied Physiology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:91e1ac00385b9cf02f966a9379c1a6e674f3404a8d64c01629f5db354dd9c0f9092e8d7ce9f1b7a502c2a6c64ffc9114756e8caa868956b84525165357d7c870
• Download URL:
  https://stacks.cdc.gov/view/cdc/196380/cdc_196380_DS1.pdf
• File Type:
  [PDF - 455.71 KB ]