Dependence of safety margins in grip force on isometric push force levels in lateral pinch.

Details

• Personal Author:
  Seo NJ
• Description:
  This study examined the relationship between safety margin and force level during an isometric push task in a lateral pinch posture. Ten participants grasped an object with an aluminium- or rubber-finished grip surface using a lateral pinch posture and exerted 20%, 40%, 60%, 80% and 100% of maximum push force while voluntary grip force was recorded. Then minimum required grip force was measured for each push force level. Mean safety margin, the difference between voluntary and minimum required grip forces, was 25% maximum voluntary contraction (MVC) when averaged for all push levels. Safety margin significantly increased with increasing push force for both grip surfaces. Grip force used during maximum push exertion was only 74% lateral pinch grip MVC. Possible underlying mechanisms for increasing safety margin with increasing push force are discussed as well as the implication of this finding for ergonomic analysis. This study demonstrates that ergonomic analyses of push tasks that involve friction force should account for safety margin and reduced grip strength during the push. Failure to consider these can result in overestimation of people's push capability. [Description provided by NIOSH]
• Subjects:
  Biomechanical Phenomena Ergonomics Musculoskeletal System Occupational Health Safety
• Keywords:
  Author Keywords: Safety Margin; Lateral Pinch; Hand; Grip Force; Push Biomechanics; Biomechanical Modeling; Ergonomics; Force; Upper Extremities; Posture;
• ISSN:
  0014-0139
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Illinois ; Michigan ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  52
• Issue:
  7
• NIOSHTIC Number:
  nn:20065341
• Citation:
  Ergonomics 2009 Jul; 52(7):840-847
• Contact Point Address:
  Na Jin Seo, Sensory Motor Performance Program, Rehabilitation Institute of Chicago, 345 E. Superior St., Suite 1406, Chicago, IL, 60611, USA
• Email:
  n-seo@northwestern.edu
• Federal Fiscal Year:
  2009
• Performing Organization:
  University of Michigan, Ann Arbor
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Ergonomics
• End Date:
  20280630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:93c5ecf00de3383a867aa6956126ab46a458599671fc57e43bf24573ab590c810274fcc9c1a0c230ac5a3c145037d290b0252defdb1dc59751b80a3ca5e24a32
• Download URL:
  https://stacks.cdc.gov/view/cdc/248839/cdc_248839_DS1.pdf
• File Type:
  [PDF - 275.17 KB ]