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Investigation of applied forces in alphanumeric keyboard work
T J Armstrong1, J A Foulke, B J Martin
1Center for Ergonomics, University of Michigan, Ann Arbor 48109-2117.
American Industrial Hygiene Association Journal
|January 1, 1994
Summary
Keyboard reaction forces can indicate finger forces during typing. Peak forces exceeded activation forces, suggesting users bottom out keys. Further research is needed on keyboard use and musculoskeletal disorders.
Area of Science:
- Ergonomics
- Human-Computer Interaction
- Occupational Health
Background:
- Keyboard use is prevalent, raising concerns about repetitive strain injuries.
- Assessing finger forces in keyboard users is crucial for occupational health.
- Understanding the force-displacement relationship in keyboards is key to mitigating injury risk.
Purpose of the Study:
- To evaluate keyboard reaction forces as an index of finger forces exerted by users.
- To investigate the relationship between keyboard reaction forces and key force-displacement characteristics.
- To inform occupational health professionals on assessing keyboard-related strain.
Main Methods:
- Tested three QWERTY keyboards according to ANSI/HFS 100-1988 standards.
- Measured peak forces, pre-travel displacement, and total key travel.
- Recorded keyboard reaction forces from 10 subjects typing alphanumeric sentences.
Main Results:
- Peak keystroke forces were 2.5 to 3.9 times the activation forces.
- Subjects consistently bottomed out keys during typing.
- The keyboard with the lowest activation force yielded the lowest average peak forces.
Conclusions:
- Keyboard reaction forces serve as a viable index for finger forces in keying tasks.
- Consistent bottoming out of keys indicates potential for increased strain.
- Further investigation is required to link keyboard reaction forces to fatigue and chronic musculoskeletal disorders.