Keyboard operating posture and actuation force: Implications for muscle over-use
✍ Scribed by M.J. Rose
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 602 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0003-6870
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✦ Synopsis
A substantial proportion of the problems in keyboard operator 'Over-use Syndromes' occur in the wrist and finger extensor muscle group. Biomechanical analysis shows these muscles to be subject to substantial sustained static (isometric) muscle contraction during the work task. This study measured the maximum relaxed finger press forces for 60 subjects in three arm support methods, in order to predict what the minimum keypress force should be to permit finger support sufficient to facilitate relaxation of finger extensor muscles. It was postulated that the minimum key activation force should accommodate the 95 percentile predicted population relaxed finger weights. The predicted force of 0.8 newton is within limits previously proposed for performance criteria, and which have been found practical commercially.