- A-Z Publications
- Ergonomics SA : Journal of the Ergonomics Society of South Africa
- Previous Issues
- Volume 25, Issue 1, 2013
Ergonomics SA : Journal of the Ergonomics Society of South Africa - Volume 25, Issue 1, 2013
Volume 25, Issue 1, 2013
Author Candice ChristieSource: Ergonomics SA : Journal of the Ergonomics Society of South Africa 25, pp 1 –2 (2013)More Less
This edition of the journal is dedicated to the lifetime work of Professor John Wilson (1951-2013) who has been described as the 'father of rail human factors'. His work was instrumental in the development of tools used routinely, worldwide, to predict workloads on signallers. He was a well known figure in the field of ergonomics and human factors and many of our teachings in South Africa have been based on his work. He started working at Loughborough University in 1974 and joined the University of Nottingham in 1983 during which time he also worked for periods at the University of California (1987-1989) and the University of New South Wales (2006-2008). He will be remembered for his exceptional contribution to the field and our heartfelt sympathies are extended to his work colleagues and family.
Source: Ergonomics SA : Journal of the Ergonomics Society of South Africa 25, pp 3 –12 (2013)More Less
Some of the vision problems associated with the use of computers have been attributed to poor ergonomic factors compliance. The aim of this study was to investigate the ergonomic factors that might lead to computer vision syndrome (CVS) among non-presbyopic computer users in a University staff population. A complete eye examination was performed on each participant before he or she was interviewed using a structured questionnaire probing into demographic status and factors that could lead to CVS. Eighty seven participants were included in the study. An observation and measurement of the participant's computer workstation was then made in order to identify the risk factors leading to CVS. Data were analysed with descriptive statistics. 72% of participants reported taking breaks after 2 hours while 28% reported taking breaks after every hour of computer use. Eye strain and visual fatigue (89%), headaches (81%), neck and back pains (77%) were the most severe and frequently reported symptoms among the participants. In general, the computer workstations were not ergonomically designed and users were not aware that they were not adhering to ergonomic requirements for computer use. This suggests the need for awareness campaigns on ergonomic factors that can prevent computer vision syndrome among computer users and early intervention programs for computer users that experience computer vision syndrome.
Source: Ergonomics SA : Journal of the Ergonomics Society of South Africa 25, pp 13 –25 (2013)More Less
The increased implementation of in-vehicle information systems presented in the different perceptual modalities and the implications this has on driver distraction has prompted a research focus in this area. The present study investigated the effect of attending to a secondary comprehension task in three different perceptual modalities on driver performance. Twenty four students participated. There were three modality conditions (central visual, peripheral visual, auditory) and two difficulty conditions (low and high). The central vision condition presented text in the central visual field, the peripheral visual condition presented text in the horizontal periphery, while pre-recorded texts were played in the auditory condition. Results confirmed that driving performance decreases with concurrent secondary task attention in any perceptual modality. Auditory distraction degrades driver performance the least (~19%) compared to pure driving, followed by central visual distraction (~31%) followed by peripheral visual distraction (~54%). These differences can be attributed to superior time-sharing of the audio-visual dichotomy, as predicted by multiple resource theory.
Surveying perceptions and practices of Philippine vegetable growers on pesticide safety and ergonomicsAuthor J.L. LuSource: Ergonomics SA : Journal of the Ergonomics Society of South Africa 25, pp 26 –38 (2013)More Less
This cross-sectional study established potential pesticide exposures and pesticide safety practices among vegetable growers in Benguet, Philippines. The study found that pesticide use was prevalent. Common work practices found a number of deficiencies, including leaking backpacks, improper labeling of pesticide containers, unvented greenhouses, sprayers and other devices not cleaned after use, not following reentry intervals, and not laundering clothing and personal protective equipment after use. These factors are ergonomic issues. Identifying and evaluating the pattern of their use would be key to the appropriateness of intervention measures. Farmers' knowledge on other equally important safety aspects of pesticide is vital in reducing pesticide exposure.
Source: Ergonomics SA : Journal of the Ergonomics Society of South Africa 25, pp 39 –51 (2013)More Less
The purpose of this study was to examine differences in muscular activation between males and females while walking in restricted postures. Restricted postures are evident in various industries, including mining, construction and agriculture. These postures are associated with musculoskeletal disorders and lower back pain. Studies generally focus on a male workforce; however, more females are entering industrial workplaces. Twelve male and 12 female subjects between the ages of 18 and 25 years participated in the study. Subjects walked on a treadmill at a speed of 3.5 km/h for four minutes under conditions of upright walking, and stooped walking under restrictions at 85% and 70% of stature. Electromyographic activity was measured on seven muscles (trapezius, latissimus dorsi, erector spinae, rectus femoris, biceps femoris, medial gastrocnemius and tibialus anterior). Ratings of Perceived Exertion (RPE) and Body Discomfort were also obtained. The extent of vertical restriction significantly altered levels of muscle activation. Female subjects had significantly lower levels of activation of the medial gastrocnemius than males. Local RPE was greatest under the lowest restriction, and body discomfort of the neck, lower back and hamstrings was evident during restricted walking. Work place design and interventions should consider these consequences.
The effects of different types of cognitive tasks in conjunction with circadian regulation on heart rate variability and performance parametersSource: Ergonomics SA : Journal of the Ergonomics Society of South Africa 25, pp 52 –67 (2013)More Less
This study aimed to determine to which extent heart rate variability (HRV) is sensitive to changes in different forms of cognitive workload. The second objective was to determine the effects of cognitive tasks on HRV during different times of the day, in conjunction with the variability of performance parameters. Five tasks were utilized, each at two levels of difficulty in order to ascertain specific cognitive resources. These tasks included a reading task, a decision-making task, a memory task and two forms of modified Fitts tasks. Only one of the modified Fitts tasks, which isolated motor organisation and the spelling error parameter for the difficult reading task showed a time of day effect with respect to performance. With respect to HRV, time domain analysis (rMSSD) and the low frequency (LF) band of a frequency domain analysis showed an overall significant effect of difficulty over all five tasks. The LF band, the high frequency (HF) band, rMSSD and heart rate frequency were sensitive to changes in cognitive workload for the memory task. The LF band was also sensitive to changes in cognitive workload for the modified Fitts task, which isolated motor organisation. The LF-HF ratio was the only HRV parameter that was influenced by the time of day during cognitive task performance. In conclusion, in some instances, HRV was sensitive to changes in cognitive workload for specific HRV parameters and tasks, with selected HRV variables also being affected by time of day. However, no straightforward assignment of workload to HRV parameters and vice versa can be made yet.