Muscular effort in four keyboard designs

The paper is addressed to the issue of health and safety in data entry task s. Its importance is in examining basic geometrical measures in the design of keyboards for optimal usage in data processing. Seven professional typis ts participated in the investigation, operating four different keyboard geo metry's. The keyboards were characterized as flat, negative, Tony and apart designs. The study includes objective and subjective parameters to identif y geometrical measures for postural comfort and muscular efforts. EMG recor dings were analyzed to determine four muscles' effort. The study indicates that a negative slope design has a geometrical advantage over three other k eyboards. EMG findings show that the effort of the Flexor muscle, while key ing with a negative keyboard design, is less by 36% than the effort found u sing Tony design, and by 58% less than using an apart design (p < 0.05). Ty ping quality was 64% lower when using Tony design and 60% lower when using apart design compared to the negative design (p < 0.05). Relevance to industry. The growing problem of work-related hazards in the expanding population of computer users was the rationale for this study which addressed itself to t he issue of design for safety and performance in keyboard operations. (C) 2 000 Elsevier Science B.V. All rights reserved.