Electromyography of the Thigh Muscles During Lifting Tasks in Kneeling and Squatting Postures

Details

• Personal Author:
  Gallagher S ; Pollard J ; Porter, William L.
• Description:
  Underground coal miners who work in low-seam mines frequently handle materials in kneeling or squatting postures. To assess quadriceps and hamstring muscle demands in these postures, nine participants performed lateral load transfers in kneeling and squatting postures, during which electromyographic (EMG) data were collected. EMG activity was obtained at five points throughout the transfer for three quadriceps muscles and two hamstring muscles from each thigh. ANOVA results indicated that EMG data for nine of 10 thigh muscles were affected by an interaction between posture and angular position of the load lifted (p50.001). Muscles of the right thigh were most active during the lifting portion of the task (lifting a block from the participant's right) and activity decreased as the block was transferred to the left. Left thigh muscles showed the opposite pattern. EMG activity for the majority of thigh muscles was affected by the size of the base of support provided by different postures, with lower EMG activity observed with a larger base of support and increased activity in postures where base of support was reduced (p50.05). Thigh EMG activity was lowest in postures with fully flexed knees, which may explain worker preference for this posture. However, such postures are also associated with increased risk of meniscal damage. Statement of Relevance: Kneeling and squatting postures are sometimes used for manual lifting activities, but are associated with increased knee injury risk. This paper examines the EMG responses of knee extensors/flexors to lifting in these postures, discusses the impact of posture and kneepads on muscle recruitment and explores the implications for work in such postures. [Description provided by NIOSH]
• Subjects:
  Biomechanical Phenomena Electrophysiology Ergonomics Mining Musculoskeletal System Occupational Health Safety
• Keywords:
  Author Keywords: Electromyography Biomechanics Body-mechanics Body-regions Electrophysiological-measurements Injury-prevention Knee-injuries Knee-protection Knee Disorders Kneeling Longwall-mining Manual-lifting Manual Material Handling Miners Motion-studies Muscle-physiology Musculoskeletal-system Posture Skeletal-movement Squatting Underground-miners

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• Series:
  Mining Publications
• ISSN:
  0014-0139
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OMSHR - Office of Mine Safety and Health Research
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  91-102
• Volume:
  54
• Issue:
  1
• NIOSHTIC Number:
  nn:20038118
• Citation:
  Ergonomics 2011 Jan; 54(1):91-102
• Contact Point Address:
  Sean Gallagher, National Institute for Occupational Safety and Health, OMSHR, PO Box 18070, Pittsburgh, PA 15236-0070, USA
• Email:
  sgallagher@cdc.gov
• Federal Fiscal Year:
  2011
• Peer Reviewed:
  True
• Source Full Name:
  Ergonomics
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:086f6214172f3e4ea7ecf248f982bb19b07512ac17df1fc7fc134d11694d14404036b9bae113ae7ec391af39a93d28fc708c00f21e08f5562a2e0674b9c329e5
• Download URL:
  https://stacks.cdc.gov/view/cdc/227300/cdc_227300_DS1.pdf
• File Type:
  [PDF - 1.60 MB ]