Effect of Contraction History on Torque Deficits by Stretches of Active Rat Skeletal Muscles

Details

• Personal Author:
  Stauber WT ; Willems MET
• Description:
  Effects of contraction history on torque deficits by stretches of active skeletal muscles were examined. After three contractions using maximal and submaximal activation (80 and 20 Hz) at an ankle position of 40 (i.e., long muscle length) and with maximal activation at 120 (i.e., short muscle length), the isometric and stretch torques (15 stretches) of rat plantar flexor muscles (bout 1) were measured. Controls were unconditioned. Stretches (i.e., ankle rotation from 90 to 40, velocity: 50 s-1) were imposed on maximal isometric contractions at 90 (i.e., preloaded stretches). All groups performed a second bout following 2 hours of rest after bout 1. After maximal contractions at long muscle length, preload torque at 90 and stretch torque at 40 for stretch 1 of bout 1 were 25% and 18% lower than the other groups. However, for all groups, bout 1 ended and bout 2 began and ended with similar isometric and stretch torques. Stretches early in bout 2, with preloads similar to stretches in bout 1, had greater stretch torques resulting in larger torque deficits. Torque deficits, possibly caused by damage to muscle structures and excitation-contraction uncoupling, were not prevented by a history of isometric contractions. Different contraction histories can result in similar isometric torques but different stretch torques. [Description provided by NIOSH]
• Subjects:
  Animals Laboratories Musculoskeletal System Occupational Health Safety
• Keywords:
  Animal Studies Author Keywords: Injury Eccentric Contractions Injuries Isometric Contractions Laboratory Animals Muscles Muscle Tissue Musculoskeletal System Prevention Skeletal System Warm-up

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• ISSN:
  1066-7814
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  323-335
• Volume:
  27
• Issue:
  4
• NIOSHTIC Number:
  nn:20029538
• Citation:
  Can J Appl Physiol 2002 Aug; 27(4):323-335
• Contact Point Address:
  Department of Biochemistry, P.O. Box 9142, West Virginia University Health Sciences Center, Morgantown, WV 26506-9142
• Federal Fiscal Year:
  2002
• NORA Priority Area:
  Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
• Performing Organization:
  West Virginia University, Morgantown, West Virginia
• Peer Reviewed:
  True
• Start Date:
  19920101
• Source Full Name:
  Canadian Journal of Applied Physiology
• End Date:
  20050531
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:4ff51a3cd7ba6b6583704639a8da16e9905389a14afa208fd8fccce6f6f28ff22cb59e4a07b6910de7c4a5cdcc145fafbc53a1f8b099ef86384c8ab94abc4c41
• Download URL:
  https://stacks.cdc.gov/view/cdc/190493/cdc_190493_DS1.pdf
• File Type:
  [PDF - 1.96 MB ]