Forced oscillations of the ankle joint.

Details

• Personal Author:
  Agarwal GC ; Gottlieb GL
• Description:
  The effects of low frequency forced vibration (3-30 hertz) applied to the ankle joint are studied in six normal human subjects. The subjects sat in a chair with the right foot strapped to a foot-plate which permitted only dorsiflexion-plantarflexion about the ankle joint. Significant nonlinearities were seen in the angular rotation of the foot over 8 to 12 hertz with torque as the driving input. The effective compliance has sharp resonance near 6.5 hertz when tonic, voluntary muscle activity is present. A two-cycle-average response was obtained for a 10 second data record by taking successive intervals equal to twice the modulation period. Fourier transform of a 10 second data record showed generation of harmonics and subharmonics of the drive frequencies. For the angular rotation, a significant proportion of the power is in harmonic frequencies when the drive frequency is from 8 to 12 hertz. The following phenomena were seen in the data: slowly increasing amplitudes of oscillation (to a limit) at drive frequencies near resonance; self-sustaining oscillations of the ankle joint near the resonant frequency after the modulation signal to the motor is turned off, particularly in the fatigued limb; and distortion (from the sinusoidal) of angular rotation during which there are spontaneous recurrences of oscillation at the drive frequency.
• Subjects:
  Accidents, Occupational Cadmium Chromium Electroplating Nickel Occupational Health Preceptorship Safety
• Keywords:
  Muscle-function Muscles Musculoskeletal-system Musculoskeletal-system-functions Physical-properties Physiological-factors
• Document Type:
  Text
• Genre:
  Conference/Symposia Proceedings
• Place as Subject:
  Illinois ; Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  50-59
• NIOSHTIC Number:
  nn:00074650
• Citation:
  Proceedings of the international occupational hand-arm vibration conference, October 28-31, 1975, Cincinnati, Ohio. Wasserman DE, Taylor W, Curry MG, eds. Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 77-170, 1977 Apr; :50-59
• Federal Fiscal Year:
  1977
• Peer Reviewed:
  False
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:91c90d41aacf8408e8746fdcddb5c725aee42f0254318eab4d62c9e317972591892c50905b5fa9256085c1a01dc774eaede78430009ba611a7377ca293e9c360
• Download URL:
  https://stacks.cdc.gov/view/cdc/178848/cdc_178848_DS1.pdf
• File Type:
  [PDF - 1.34 MB ]