Ergonomic requirements for computer input devices

Status:

completed 12/2006

Aims:

Detailed requirements profiles, in particular containing criteria for body posture and biomechanical stress, are required for practicable testing of the ergonomic aspects of computer input devices. The annexes of the standards DIN EN ISO 9241-9, "Ergonomic requirements for office work with visual display terminals (VDTs) - Part 9: Requirements for non-keyboard input devices" and DIN EN ISO 9241-4, "Ergonomic requirements for office work with visual display terminals (VDTs) - Part 4: Keyboard requirements for visual display terminals" contain information on means of testing and assessing the fitness for use, efficiency and effectiveness, user satisfaction, and other assessment methods. The introductions to Annexes C and D of DIN EN ISO 9241-9 explicitly state that this information concerning methods involving assessment scales, analyses of body posture and measurements of biomechanical stress is mentioned in this context for the purpose of encouraging research in these areas. It would be desirable for the results of such research to lead to further information becoming available on the ergonomic design of input devices. The methods for the analysis of body posture and the measurement of biomechanical stress which have been used to date, particularly those referred to, are technically very involved and require specially trained test managers. The objective of this project was therefore to produce a catalogue of ergonomic criteria for computer input devices which could be included in a test method for use by occupational physicians and workplace designers.

Activities/Methods:

A literature survey was first to be performed for the purpose of analysing existing knowledge on the ergonomics of input devices. Based upon this survey, a catalogue of physiological/biomechanical criteria was to be drawn up for the ergonomic assessment of input devices. The results were to be documented in a report containing a description of the progress of research, the catalogue of selected physiological/biomechanical criteria, the rationale for the selected criteria, and a proposal for their assessment.

Results:

The results of the literature survey are available in the form of a report for the following input devices: keyboard, mouse, trackball, and tablet & stylus. During assessment of the ergonomics literature, the use of handrests and armrests was found to have a major influence upon the ergonomic assessment of input devices. The literature study was therefore extended to include this subject. The report first describes the procedure followed for the survey and evaluation of the ergonomics literature. The criteria identified for the input devices referred to above and their biomechanical/physiological justification are then presented and explained, and discussed with reference to the standards DIN EN ISO 9241-9 and DIN EN ISO 9241-4. Finally, a checklist is drawn up for keyboard and mouse. The purpose of the checklist is to assist occupational physicians in recognizing work-related causes of complaints, and in finding suitable solutions, possibly in conjunction with ergonomics experts, OH&S professionals and/or other persons concerned with OH&S issues.

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