Differences in Typing Forces, Muscle Activity, Wrist Posture, Typing Performance, and Self-Reported Comfort Among Conventional and Ultra-Low Travel Keyboards

Details

• Personal Author:
  Johnson PW ; Kia K ; Kim JH ; Sisley J
• Description:
  This study investigated the relative impact of ultra-low travel keyboards on typing force, muscle activity, wrist posture, typing performance, and self-reported comfort/preference as compared to a conventional keyboard. In a repeated-measures laboratory-based study, 20 subjects were invited to type for 10 min on each of five keyboards with different travel distances of 0.5, 0.7, 1.2, 1.6 (ultra-low travel keyboards), and 2.0 mm (a conventional keyboard). During the typing sessions, we measured typing force; muscle activity in extrinsic finger muscles (flexor digitorum superficialis and extensor digitorum communis), shoulder (trapezius) and neck (splenius capitis); wrist posture; typing performance; and self-reported comfort/preference. While using the ultra-low travel keyboards, subjects typed with less force and wrist extension, and had more ulnar deviation (p's < 0.0001) compared with conventional keyboard. However, these differences in typing forces were less than 0.5 N and less than 4 degrees for both wrist extension and ulnar deviation. The general trend of data did not show any consistent or substantial differences in muscle activity (less than 2 %MVC) and typing performance (<5 WPM in speed; < 3% in accuracy), despite the observed statistical difference in the finger flexors and extensors muscle activity (p's < 0.19) and typing performance (p < 0.0001). However, the subjects preferred using conventional keyboards in most of the investigated self-reported comfort and preference criteria (p's < 0.4). In conclusion, these small differences indicate that using ultra-low travel keyboards may not have substantial differences in biomechanical exposures and typing performance compared to conventional keyboard; however, the subjective responses indicated that the ultra-low keyboards with the shortest key travel tended to be the least preferred. [Description provided by NIOSH]
• Subjects:
  Biomechanical Phenomena Computers Environmental Exposure Ergonomics Laboratories Musculoskeletal Diseases Musculoskeletal System Occupational Health Safety
• Keywords:
  Author Keywords: Computer-related Musculoskeletal Disorders Biomechanics Computer Equipment Electromyography Equipment Design Exposure Levels Force Force-displacement Characteristics Keyboards Key Travel Distance Laboratory Testing MSD Muscle Function Musculoskeletal Disorders Posture Upper Extremities Usability

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• ISSN:
  0003-6870
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Oregon ; OSHA Region 10 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  10-16
• Volume:
  74
• NIOSHTIC Number:
  nn:20055009
• Citation:
  Appl Ergon 2019 Jan; 74:10-16
• Contact Point Address:
  Jeong Ho Kim, College of Public Health and Human Sciences, Oregon State University, 20B Milam Hall, Corvallis, OR 97331
• Email:
  jay.kim@oregonstate.edu
• Federal Fiscal Year:
  2019
• Performing Organization:
  University of Washington
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Applied Ergonomics
• End Date:
  20250630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:52bec9727b89f7de6bcdc9e4f5c4ba51dd429c375f24b4c7386a148926d1a38c921fa7ee4aaa445e5e572b8b568e22b2f8f3d7c1aa577cad149815c54cc037a2
• Download URL:
  https://stacks.cdc.gov/view/cdc/217413/cdc_217413_DS1.pdf
• File Type:
  [PDF - 656.82 KB ]