A Flexed Wrist Results in Larger Muscle Stresses During Tapping

Details

• Personal Author:
  Asundi K ; Chen H ; Dennerlein, Jack T.
• Description:
  Sustained non-neutral wrist postures during computer use have been identified as a risk factor for tendon injuries. A possible mechanism for injury may be that these non-neutral postures lengthen muscles and thus increase passive loads. Three non-neutral wrist postures, adduction, extension, and flexion, are common during typing. Adducted and extended wrist postures have been observed during keyboard intensive tasks. Typing on a negatively tilted keyboard, which is intended to reduce wrist extension and thus the risk of musculoskeletal disorders, could result in flexed wrist postures. Non-neutral postures lengthen muscles selectively. Wrist adduction, extension, or flexion lengthens the abductor, flexor, or extensor muscles, respectively. The lengthened muscles develop passive stresses as a function of excursion and muscle elasticity. This study compared hand and forearm muscle stresses during index finger tapping across four wrist postures using a computational model. We hypothesized that non-neutral wrist postures would lead to larger muscle stresses than in neutral posture due to the influence of passive stresses. [Description provided by NIOSH]
• Subjects:
  Biomechanical Phenomena Computers Ergonomics Musculoskeletal Diseases Musculoskeletal System Occupational Health Safety
• Keywords:
  Biomechanics Computer Equipment Keyboards MSD Muscle Function Musculoskeletal Disorders Posture Upper Extremities
• Publisher:
  American Society of Biomechanics
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  Massachusetts ; OSHA Region 1
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20060537
• Citation:
  Proceedings of the 34th Annual Meeting of the American Society of Biomechanics, August 18-21, 2010, Providence, Rhode Island. Newark, DE: The American Society of Biomechanics, 2010 Aug; :111
• Email:
  jax@hsph.harvard.edu
• Federal Fiscal Year:
  2010
• NORA Priority Area:
  Services ; Wholesale and Retail Trade
• Performing Organization:
  Harvard University School of Public Health
• Peer Reviewed:
  False
• Start Date:
  20070301
• Source Full Name:
  Proceedings of the 34th Annual Meeting of the American Society of Biomechanics, August 18-21, 2010, Providence, Rhode Island
• End Date:
  20120331
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1b8fff8dcbe122a92966757521d458a700645c69d6d4e0a195991908c63f0ce65fff3859610da8084bcaf4f841a36bc4ee2ff605aa52b92149136a3182d31ffd
• Download URL:
  https://stacks.cdc.gov/view/cdc/224405/cdc_224405_DS1.pdf
• File Type:
  [PDF - 30.07 KB ]