Performance of Rat Plantar Flexor Muscles by Active Stretching During Ankle Rotations and Isometric Contractions

Details

• Personal Author:
  Stauber WT ; Willems ME
• Description:
  The performance of rat plantar flexor muscles by repeated stretches (30) using velocity-controlled ankle rotations from 1.57 to 0.70 rad (0.87 rad s-1: slow stretch, 10.47 rad s-1: fast stretch) and repeated isometric contractions (30) at 1.13 rad was examined. Performance was assessed by the isometric force at ankle positions of 1.57 and 0.70 rad and the time to produce 50% of the maximal force at 1.57 rad. Stretches were superimposed on maximally active muscles. Rest periods (3 min) between contractions (1900 ms) eliminated effects of fatigue. Isometric contractions resulted in a linear reduction in force at 1.57 rad (total deficit 13.8%). For slow and fast stretches, half of the total deficit at 1.57 rad (about 30%) was completed after six stretches. From stretch number 18 to number 30, slow stretches tend to produce greater force deficits, although this was not significant (two way ANOVA, P=0.09). Half contraction times increased linearly for stretches but were larger than for isometric contractions. Reductions in isometric force were greater at an ankle position of 1.57 rad than at 0.70 rad. One hour of rest following the stretches and isometric contractions did not restore muscle performance. It is concluded that isometric contractions of skeletal muscle can create a force deficit which is much less than that following stretches. The velocity of ankle rotations producing stretches of rat plantar flexor muscles working in situ is not a factor in reducing muscle performance. [Description provided by NIOSH]
• Subjects:
  Dust Engineering Mining Occupational Health Safety
• Keywords:
  Animals Animal Studies Fatigue Laboratory Animals Muscles Musculoskeletal System Skeletal System
• ISSN:
  0195-9131
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  31
• NIOSHTIC Number:
  nn:20029519
• Citation:
  Med Sci Sports Exerc 1999 May; 31(Suppl 5):S74
• Contact Point Address:
  Department of Biochemistry, P.O. Box 9142, West Virginia University Health Sciences Center, Morgantown, WV 26506-9142
• Federal Fiscal Year:
  1999
• NORA Priority Area:
  Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
• Performing Organization:
  West Virginia University, Morgantown, West Virginia
• Peer Reviewed:
  False
• Start Date:
  19920101
• Source Full Name:
  Medicine and Science in Sports and Exercise
• Supplement:
  5
• End Date:
  20050531
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:913df3b05e9db0e8a2d0a2db0179e6a0cbb7981d75610ec52a86de9c0a1a3ceea6b014e906b8b64c31990fe45caeea4ba27ba1868792bad570e50c63e1156d50
• Download URL:
  https://stacks.cdc.gov/view/cdc/190475/cdc_190475_DS1.pdf
• File Type:
  [PDF - 37.75 KB ]