The Effect of Alternative Keyboards on Discomfort and Typing Kinematics

Details

• Personal Author:
  Baker NA ; Lee ZM
• Description:
  Non-neutral postures of the arm/hand during keyboard operation are considered to be risk factors for musculoskeletal disorders (MSD) and musculoskeletal discomfort. Alternative keyboards have built-in angles designed to eliminate non-neutral postures. They have become the number one selling keyboards in the US based on the assumption that they reduce discomfort by eliminating these types of postures. While studies demonstrate that alternative keyboards improve non-neutral postures, there are few studies that suggest that they reduce discomfort. This crossover, randomized trial evaluated the effectiveness of an alternative, fixed, split-angle (FSA) keyboard (Microsoft Natural) compared to a flat standard (ST) keyboard. Eighty-five participants were randomly assigned to either Group 1 (ST keyboard switched to FSA keyboard) or Group 2 (FSA switched to ST keyboard). Participants documented discomfort of the neck, back, and right/left arm/hand weekly for 12 months (5-6 months per keyboard), and identified the usability of their current keyboard monthly. We obtained kinematics data on participants' postures during keyboard use at baseline, 5-6 months, and 12 months. Eighty-five participants enrolled in the study, 44 in Group 1 and 41 in Group 2. Data analyses were completed on 77 participants. Participants were primarily female, aged 44 years (SD = 12.4 years) and worked an average of 6.2 hours per day at the computer. Ninety-three percent reported a level 2 or greater discomfort, on a scale to 10, for the neck, 85.7% reported discomfort in the back, and 89.6% and 59.7% reported discomfort in the right and left arm/hands respectively. There were no significant differences in the proportion of participants experiencing musculoskeletal discomfort when using the FSA keyboard in comparison to the ST keyboard after 5 to 6 months for all body parts. In all cases, a majority of participants started with discomfort, within 5 to 15 weeks the proportion had dropped to approximately 20%, regardless of the keyboard used. At 20-24 weeks the keyboards were switched. The proportion of participants with discomfort remained essentially stable at approximately 20% and continued at that level for the remainder of the study. Participants reported that the ST keyboard was significantly more usable than the FSA keyboard even after 5 to 6 months of use, although half of the sample reported that they would prefer to continue using the FSA keyboard. We completed kinematics data analyses on 40 participants. The FSA keyboard significantly reduced non-neutral postures for the forearm/wrist, but significantly increased non-neutral postures for left middle and ring and left/right little finger MCP flexion/extension. Kinematics remained stable from baseline to follow-up. There were few significant associations between discomfort and postures. The results do not support the use of FSA keyboards to reduce the burden of discomfort for computer operators. FSA keyboards were no more effective at reducing musculoskeletal discomfort than flat ST keyboards. Additionally, many computer operators found FSA keyboards difficult to use. Given that FSA keyboards are no more effective than ST keyboards in reducing discomfort and potentially more difficult to use, employers should be cautious about purchasing and implementing FSA keyboards with their computer operators. [Description provided by NIOSH]
• Subjects:
  Computers Ergonomics Musculoskeletal Diseases Musculoskeletal System Occupational Health Safety
• Keywords:
  Computer Equipment Keyboard Operators Keyboards MSD Musculoskeletal Disorders Posture Upper Extremities
• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-18
• NIOSHTIC Number:
  nn:20056584
• NTIS Accession Number:
  PB2019-101408
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R01-OH-008961, 2013 Nov; :1-18
• Contact Point Address:
  Nancy A. Baker, ScD, MPH, OTR/L, University of Pittsburgh, 5012 Forbes Tower, Pittsburgh, PA 15260
• Email:
  nab36@pitt.edu
• Federal Fiscal Year:
  2014
• NORA Priority Area:
  Services ; Healthcare and Social Assistance
• Performing Organization:
  University of Pittsburgh at Pittsburgh
• Peer Reviewed:
  False
• Start Date:
  20080901
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20130831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1264aad0b5699d30d50b10f43d442f0b612a9657bd915ba9407f765450f58c80713e8a30f2259a09b8fd93a017776d67d043bc9a30ad4ab3b55e7db636734ba7
• Download URL:
  https://stacks.cdc.gov/view/cdc/218902/cdc_218902_DS1.pdf
• File Type:
  [PDF - 232.20 KB ]