A model of visual and musculoskeletal strain associated with computer monitor placement was developed. The main premise of which is that monitor placement decisions must take into consideration development of both visual and musculoskeletal strains. Certain factors in the model that were thought to affect one or both types of strain, or that were considered important to rule out for effect, were tested in a lab setting. These factors were viewing angle (eye level, midlevel, low level), monitor size (14 in., 19 in.), keyboard familiarity (touch typist, nontouch typist), and task (reading, mousing, typing). Outcomes included indicators of visual and musculoskeletal strain, preference, and performance. Muscle activity was generally greater for the low viewing angle, for the standard monitor (14 in.), and for non-touch typists. Participants preferred the midlevel placement. Task performance was slightly diminished with eye-level placement. Results are interpreted in relation to the model and to several hypotheses that were formed to focus the inquiry. Actual or potential applications of this research include monitor placement decisions in the design or modification of computer workstations
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References
1.
Aarås, A., Horgen, G., Bjorset, H. H., Ro, O., & Thoresen, M. (1998). Musculoskeletal, visual and psychosocial stress in VDU operators before and after multidisciplinary ergonomic interventions. Applied Ergonomics, 29, 335–354.
2.
Ankrum, D. R., & Nemeth, K. J. (1995). Posture, comfort, and monitor placement. Ergonomics in Design, 31, 7–9.
3.
Bauer, W. & Wittig, T. (1998). Influence of screen and copy holder positions on head posture, muscle activity and user judgement. Applied Ergonomics, 29, 185–192.
4.
Bergqvist, U. O., & Knave, B. G. (1994). Eye discomfort and work with visual display terminals. Scandinavian Journal of Work, Environment, and Health, 20, 27–33.
5.
Bergqvist, U. O., Wolgast, E., Nilsson, B., & Voss, M. (1995). Musculoskeletal disorders among visual display terminal workers: Individual, ergonomic, and work organizational factors. Ergonomics, 38, 763–776.
6.
Borg, G. A. V. (1982). Psychophysical bases of perceived exertion. Medicine and Science in Sports and Exercise, 14, 377–381.
7.
Burgess-Limerick, R., Plooy, A., & Ankrum, D. R. (1998). The effect of imposed and self-selected computer monitor height on posture and gaze angle. Clinical Biomechanics, 13, 584–592.
8.
Cailliet, R. (1991). Neck and arm pain (3rd ed.). Philadelphia: F. A. Davis.
9.
Chaffin, D. B. (1973). Localized muscle fatigue-Definition and measurement. Journal of Occupational Medicine15, 346–354.
10.
de Wall, M., van Riel, M. P. J. M., Aghina, J. C. F. M., Burdorf, A., & Snijders, C. J. (1992). Improving the sitting posture of CAD/CAM workers by increasing VDU monitor working height. Ergonomics, 35, 427–436.
11.
Grandjean, E.Hünting, W., & Pidermann, M. (1983). VDT workstation design: Preferred settings and their effects. Human Factors, 25, 161–175.
12.
Gray, F. E., Hanson, J. A., & Jones, F. P. (1966). Postural aspects of neck muscle tension. Ergonomics, 9, 245–256.
13.
Grieco, A.Molteni, G., Piccoli, B., & Perris, R. (1982). Field study In newspaper printing: A systematic approach to VDU operator strain. In E. Grandjean & E. Vigliani (Eds.), Ergonomic aspects of visual display terminals (pp. 185–194). London: Taylor & Francis.
14.
Guthrie, E. R. (1952). The psychology of learning.New York: Harper Row.
15.
Hagberg, M.Silverstein, B., Wells, R., Smith, M. J., Hendrick, H. W., Carayon, P., & Perusse, M. (1995). Work related musculoskeletal disorders (WMSDs): A reference book for prevention.London: Taylor & Francis.
16.
Hamilton, N. (1996). Source document position as it affects head position and neck muscle tension. Ergonomics, 39, 593–610.
17.
Heuer, H. & Owens, D. A. (1989). Vertical gaze direction and the resting posture of the eyes. Perception, 18, 363–377.
18.
Hill, S. G., & Kroemer, K. H. E. (1986). Preferred declination of the line of sight. Human Factors, 28, 127–134.
19.
Human Factors and Ergonomics Society (1988). American national standard for human factors engineering of visual display terminal workstations (ANSI/HFS 100-1988). Santa Monica, CA: Human Factors and Ergonomics Society.
20.
Hunting, W.Laubli, T., & Grandjean, E. (1981). Postural and visual loads at VDT workplaces: I. Constrained postures. Ergonomics, 24, 917–931.
21.
ISO. (1992). Ergonomic requirements for office work with visual display terminals (VDTs) - Workplace requirements (ISO 9241- 3). Geneva: International Organization for Standardization.
22.
Jampel, R. S., & Shi, D. X. (1992). The primary position of the eyes, the resetting saccade, and the transverse visual head plane. Investigative Ophthalmology & Visual Science, 33, 2501–2510.
23.
Jaschinski, W.Heuer, H., & Kylian, H. (1998). Preferred position of visual displays relative to the eyes: A field study of visual strain and individual differences. Ergonomics, 41, 1034–1049.
24.
Jaschinski-Kruza, W. (1991). Eyestrain in VDU users: Viewing distance and the resting position of ocular muscles. Human Factors, 33, 69–83.
25.
Jonsson, B. (1978). Kinesiology, with special reference to electromyographic kinesiology. In W. A. Cobb & H. Van Duijn (Eds.), Contemporary clinical neurophysiology (pp. 417–428). Amsterdam: Elsevier Scientific.
26.
Kendall, F. P., & McCreary, E. K. (1983). Muscles, testing and function (3rd ed.). Baltimore: Waverly.
27.
Kilbom, Å., & Persson, J. (1987). Work technique and its consequences for musculoskeletal disorders. Ergonomics, 30, 273–279.
28.
Kumar, S. (1994). A computer desk for bifocal lens wearers, with special emphasis on selected telecommunication tasks. Ergonomics, 37, 1669–1678.
29.
Lie, I. & Fostervold, K. I. (1994). VDT-work with different gaze inclinations. In Proceedings of the WWDU'94 (pp. D40--D42). Milan: Institute of Occupational Health.
30.
Lu, H. & Aghazadeh, F. (1993). VDT positions: Effect on performance and comfort. In Proceedings of the Human Factors and Ergonomics Society 37th Annual Meeting (pp. 397--400). Santa Monica, CA: Human Factors and Ergonomics Society.
31.
Lundervold, A. (1958). Electromyographic investigations during typewriting. Ergonomics, 1, 226–233.
32.
Menozzi, M. v.Buol, A., Krueger, H., & Miège, C. (1994). Direction of gaze and comfort: Discovering the relation for the ergonomic optimization of visual tasks. Ophthalmic and Physiological Optics, 14, 393–399.
33.
Mon-Williams, M., Burgess-Limerick, R., Plooy, A., & Wann, J. (1999). Vertical gaze direction and postural adjustment: An extension of the Heuer model. Journal of Experimental Psychology: Applied, 5, 35–53.
34.
Raine, S. & Twomey, L. T. (1997). Head and shoulder posture variations in 160 asymptomatic women and men. Archives of Physical Medicine and Rehabilitation, 78, 1215–1223.
35.
Ripple, P. H. (1952). Variation of accommodation in vertical directions of gaze. American Journal of Ophthalmology, 35, 1630–1634.
36.
Schmidt, R. A. (1991). Motor learning and performance: From principles to practice.Champaign, IL: Human Kinetics.
37.
Schüldt, K., Ekholm, J., Harms-Ringdahl, K., Nemeth, G., & Arborelius, U. P. (1986). Effects of changes in sitting work posture on static neck and shoulder muscle activity. Ergonomics, 29, 1525–1537.
38.
Sjøgaard, G., & Søgaard, K. (1998). Muscle injury in repetitive motion disorders. Clinical Orthopaedics and Related Research, 351, 21–31.
39.
Sotoyama, M.Jonai, H., & Saito, S. (1996). Analysis of ocular surface area for comfortable VDT workstation layout. Ergonomics, 39, 877–884.
40.
Staudte, H.-W., & Dühr, N. (1994). Age- and sex-dependent force-related function of the cervical spine. European Spine Journal, 3, 155–161.
41.
Turville, K. L., Psihogios, J. P., Ulmer, T. R., & Mirka, G. A. (1998). The effects of video display terminal height on the operator: A comparison of the 15 degree and 40 degree recommendations. Applied Ergonomics, 29, 239–246.
42.
Tyrrell, R. A., & Leibowitz, H. W. (1990). The relation of vergence effort to reports of visual fatigue following prolonged near work. Human Factors, 32, 341–357.
43.
Villanueva, M. B., Jonai, H., & Saito, S. (1998). Ergonomic aspects of portable personal computers with flat panel displays (PCFPDs): Evaluation of posture, muscle activities, discomfort and performance. Industrial Health, 36, 282–289.
44.
Villanueva, M. B., Jonai, H., Sotoyama, M., Hisanaga, N., Takeuchi, Y., & Saito, S. (1997). Sitting posture and neck and shoulder muscle activities at different screen height settings of the visual display terminal. Industrial Health, 35, 330–336.
45.
Villanueva, M. B., Sotoyama, M., Jonai, H., Takeuchi, Y., & Saito, S. (1996). Adjustments of posture and viewing parameters of the eye to changes in the screen height of the visual display terminal. Ergonomics, 39, 933–945.
46.
Watson, D. H., & Trott, P. H. (1993). Cervical headache: An investigation of natural head posture and upper cervical flexor muscle performance. Cephalgia, 13, 272–284.
47.
Carolyn M. Sommerich is an assistant professor of industrial engineering at North Carolina State University, Raleigh, North Carolina. She received a Ph.D. in industrial and systems engineering from Ohio State University in 1994.
48.
Sharon M. B. Joines is an ergonomist at the North Carolina Ergonomics Resource Center and a Ph.D. student at North Carolina State University, Raleigh, North Carolina. She received an M.S. in industrial engineering from North Carolina State University in 1996.
49.
Jennie P. Psihogios is Hardware Usability and Ergonomics Team Leader for the Human Factors Engineering Group at NCR Corporation, Duluth, Georgia. She received an M.S. in industrial engineering from North Carolina State University in 1998.
