Wrist and shoulder posture and muscle activity during touch-screen tablet use: effects of usage configuration, tablet type, and interacting hand

Details

• Personal Author:
  Dennerlein, Jack T. ; Marinelli K ; Odell D ; Trudeau M ; Young JG
• Description:
  BACKGROUND: Due to its rapid growth in popularity, there is an imminent need for ergonomic evaluation of the touch-screen tablet computing form-factor. OBJECTIVE: The aim of this study was to assess postures of the shoulders and wrists and their associated muscle activity during touch-screen tablet use. METHODS: Fifteen experienced adult tablet users completed a set of simulated software tasks on two media tablets in a total of seven user configurations. Configurations consisted of a combination of a support condition (held with one hand, two hands or in a case), a location (on the lap or table surface), and a software task (web browsing, email, and game). Shoulder postures were measured by using an infra-red LED marker based motion analysis system, wrist postures by electro-goniometry, and shoulder (upper trapezius and anterior deltoid) and forearm (flexor carpi radialis, flexor carp ulnaris, and extensor radialis) muscle activity by surface electromyography. RESULTS: Postures and muscle activity for the wrist significantly varied across configurations and between hands, but not across the two tablets tested.Wrist extension was high for all configurations and particularly for the dominant hand when a tablet was placed on the lap (mean = 38.). Software tasks involving the virtual keyboard (e-mailing) corresponded to higher wrist extensor muscle activity (50th percentile = 9.5% MVC) and wrist flexion/extension acceleration (mean = 322./s2). High levels of wrist radial deviation were observed for the non-dominant hand when it was used to tilt and hold the tablet (mean = 13.). Observed differences in posture and muscle activity of the shoulder were driven by tablet location. CONCLUSION: Touch-screen tablet users are exposed to extreme wrist postures that are less neutral than other computing technologies and may be at greater risk of developing musculoskeletal symptoms. Tablets should be placed in cases or stands that adjust the tilt of the screen rather than supporting and tilting the tablet with only one hand. [Description provided by NIOSH]
• Subjects:
  Biomechanical Phenomena Communications Media Computers Ergonomics Eye Laboratories Musculoskeletal System Occupational Health Safety Sense Organs Software

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• Keywords:
  Author Keywords: Slate Computing Biomechanics Communication-systems Computer-equipment Computer-software Equipment-design Humans Laboratory-testing Measurement-equipment Media Tablets Mobile Computing Motion-studies Muscle-function Muscles Musculoskeletal-system Physiological-measurements Physiological-testing Posture Simulation-methods Visual-fields Visual-motility

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• ISSN:
  1051-9815
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; Massachusetts ; Michigan ; OSHA Region 1 ; OSHA Region 10 ; OSHA Region 5 ; OSHA Region 9 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  59-71
• Volume:
  45
• Issue:
  1
• NIOSHTIC Number:
  nn:20043046
• Citation:
  Work 2013 May; 45(1):59-71
• Contact Point Address:
  Jack T. Dennerlein, Northeastern University, Department of Physical Therapy, 6 Robinson Hall, 360 Huntington Ave, Boston, MA 02115, USA
• Email:
  j.dennerlein@neu.edu
• Federal Fiscal Year:
  2013
• Performing Organization:
  Harvard University School of Public Health
• Peer Reviewed:
  True
• Start Date:
  20070301
• Source Full Name:
  Work
• End Date:
  20120228
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:a19a170f7e7eed77965b3bf144eaebeef386e6ed0cbf74f6aa6133fdafbffe6ddbc4474e8db2cf2f930796b716db1016c820810e89ebd1807204be33c7da38d4
• Download URL:
  https://stacks.cdc.gov/view/cdc/195068/cdc_195068_DS1.pdf
• File Type:
  [PDF - 2.13 MB ]