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The Effect of Using a Laptopstation Compared to Using a Standard
Laptop PC on the Cervical Spine Torque, Perceived Strain and
Productivity.
Berkhout, A.L., Hendriksson-Larsén, K. and Bongers, P. (2004), Applied
Ergonomics, 35 (2), 147-152
The objective of this study was to assess the effect of using a laptopstation and a
laptop PC and how this difference in work set-up affected the mechanical load on the
neck (C7-Th1 segment), the subjective evaluation of strain on the neck and productivity.
Ten healthy male students at Umeå University, Sweden with an average of 10 years of
PC work experience and an average of 18 months of laptop PC work experience
participated in the study. For each research subject measurements were divided into two
parts; sitting working at the ErgoQ laptopstation in test situation A, and sitting working at
a conventional laptop PC, test situation B. Each part took 4 h and was scheduled on two
consecutive days. Photography and biomechanical analysis was used to calculate the
torque at the neck. To examine perceived strain the Borg Scale was used and to assess
performance a productivity score was calculated. The results in the study demonstrated a
significant (p<0.05) difference with the use of the laptop station resulting in decreased
torque at the C7-Th1 segment, less perceived strain at the neck and a higher productivity
score (17% increase). In conclusion, the results of the study confirm the importance of
adjustable work tools that recognize anthropometric differences and biomechanics to
meet the needs of individual customers during continuous visual display terminal work.
Upper Quadrant Postural Changes of School Children in Response to
Interaction With Different Information Technologies
Briggs, A., Straker, L., et al. (2004), Ergonomics, 47(7), 790-819.
The objective of this study was to quantitatively analyze the sitting posture of
school children interacting with both old (book) and new (laptop and desktop computers)
information technologies to test the hypothesis that posture is effected by the type of
information technology (IT) used. A mixed model design was used to test the effect of IT
type (within subjects) and age and gender (between subjects). The sitting posture of 32
children aged 4-17 years was measured whilst they read from a book, laptop, and desktop
computer at a standard school chair and desk. Video images were captured and then
digitized to calculate mean angles for head tilt, neck flexion, trunk flexion, and gaze
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angle. Posture was found to be influenced by IT type (p < 0.001), age (p < 0.001) and
gender (p = 0.024) and significantly correlated to the stature of the participants.
Measurement of resting posture and the maximal range of motion of the upper and lower
cervical spines in the sagittal plane was also undertaken. The biophysical impact and the
suitability of the three different information technologies are discussed.
Recent Ergonomic Features of Notebook PCs
Yoshitake, R. and Moriguchi, K. (2003), “Ergonomics in the Digital Age.",
Proceedings of the XVth Triennial Congress of the International Ergonomics
Association and the 7th Joint Conference of the Ergonomics Society of Korea
and the Japan Ergonomics Society”, Vol. 3, Seoul, Korea, August 24-29,
2003. Ergonomics Society of Korea, Seoul, Korea. 2pp .
Notebook PCs are spreading in the market and they are effectively used by mobile
workers. Since portability is one of the most important features for notebook PCs, they
have different features from desktop PCs. Therefore ergonomics considerations for
notebook PCs are needed when notebook PCs are used both at the office and at home. In
this paper, the ergonomics characteristics of notebook PCs are introduced.
Towards the Promotion of Health and Safety in the Use of Notebook
Personal Computers
Saito, S., Jonai, H. and Villanueva, M.B.G. (2003), “Ergonomics in the Digital
Age," Proceedings of the XVth Triennial Congress of the International
Ergonomics Association and the 7th Joint Conference of the Ergonomics
Society of Korea and the Japan Ergonomics Society”, Vol. 3, Seoul, Korea,
August 24-29, 2003. 3pp
The compact design of notebook personal computers does not allow the same
range of adjustability seen with desktop types. Hence, more constrained posture and
impeded performance have been reported among its users. A proactive approach to avert
foreseeable health problems is the issuance of ergonomics guidelines for notebook
personal computers. This paper presents the rationale and essential features of the
guidelines.
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Ergonomic Concerns in the Use of a Notebook PC
Jonai, H., Villanueva, M.B.G., Sotoyama, M., Marumoto, T. and Saito, S.
(2003), “Ergonomics in the Digital Age," Proceedings of the XVth Triennial
Congress of the International Ergonomics Association and the 7th Joint
Conference of the Ergonomics Society of Korea and the Japan Ergonomics
Society”, Vol.3, Seoul, Korea, August 24-29, 2003. 3pp
VDT work is considered constraining because it requires a definite position for
the eyes in order to see well and the hands in order to use the keyboard or mouse. Some
researchers have pointed out that the use of a notebook PC would produce more
ergonomics problems than a desktop computer. Recommendations on how to reduce
physical stress while using a notebook PC are proposed in this paper.
Ergonomic Evaluation of Work Posture for Using a Notebook PC
Saito, S., Katoh, Z. and Miyao, M. (2003), Ergonomic concerns in the use of a
notebook PC. In “Ergonomics in the Digital Age. Proceedings of the XVth
Triennial Congress of the International Ergonomics Association and the 7th
Joint Conference of the Ergonomics Society of Korea and the Japan
Ergonomics Society”, Vol.3, Seoul, Korea, August 24-29, 2003. 4pp
The aim of this study was to evaluate working conditions using notebook PCs
(NPC) in terms of visual and musculoskeletal comfort. Work posture using an NPC was a
remarkably short viewing distance and forward head inclination. To prevent visual and
musculoskeletal disorders using notebook PCs , these VDT devices should be arranged to
give each operator a more upright head and neck position. The addition of a mechanism
for adjustment of the height of the flat panel display would avoid the poor posture.
A Comparison of the Postures Assumed When Using Laptop
Computers and Desktop Computers
Straker, L., Jones K.J. and Miller J. (1997), Applied Ergonomics, 28 (4), 263268.
This study evaluated the postural implications of using a laptop computer. Laptop
computer screens and keyboards are joined, and are therefore unable to be adjusted
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separately in terms of screen height and distance, and keyboard height and distance. The
posture required for their use is likely to be constrained, as little adjustment can be made
for the anthropometric differences of users. In addition to the postural constraints, the
study looked at discomfort levels and performance when using laptops as compared with
desktops. Statistical analysis showed significantly greater neck flexion and head tilt with
laptop use. The other body angles measured (trunk, shoulder, elbow, wrist, and scapula
and neck protraction/retraction) showed no statistical differences. The average discomfort
experienced after using the laptop for 20min, although appearing greater than the
discomfort experienced after using the desktop, was not significantly greater. When using
the laptop, subjects tended to perform better than when using the desktop, though not
significantly so. Possible reasons for the results are discussed and implications of the
findings outlined.