Ergonomics SA : Journal of the Ergonomics Society of South Africa - latest Issue
Volume 28, Issue 2, 2016
Author Candice ChristieSource: Ergonomics SA : Journal of the Ergonomics Society of South Africa 28, pp 1 –1 (2016) http://dx.doi.org/10.4314/esa.v28i2.1More Less
I would like to welcome Dr. Jonathan Davy to the Editorial Board. Dr. Davy joins us as Associate Editor from Rhodes University. He has a PhD in Human Kinetics and Ergonomics and has expertise in the field of sleep research. I know that he will make a substantial contribution to the journal and I look forward to working with him.
Comparing fatigue responses between healthy individuals and asymptomatic low back pain sufferers - implications for return-to-work : a pilot studySource: Ergonomics SA : Journal of the Ergonomics Society of South Africa 28, pp 2 –18 (2016) http://dx.doi.org/10.4314/esa.v28i2.2More Less
Although most LBP episodes are acute, research suggests that up to two-thirds of people suffer pain relapses within a year. As muscle fatigue is considered a risk factor for the development of work-related musculoskeletal disorder, it was hypothesised that workers, who have seemingly recovered, i.e. are asymptomatic, display premature fatigue responses and may therefore be at elevated risk of re-injury. 30 volunteers were recruited: 10 without LBP history, 10 participants who experienced their last bout of symptoms between 9 and 12 months ago, and 10 participants who had been injured within the last 3 months. All groups were matched for basic demographic variables and individuals with LBP history were pain-free. Participants performed a self-paced repetitive lifting and lowering task until they reached a rating of perceived exertion (RPE) for the back of 17. Isometric back strength and joint position sense (deviation from 45o trunk flexion) were measured pre and post protocol. Task duration, back RPE, and sEMG of selected trunk and leg muscles were recorded throughout the protocol. Statistical significance was identified at p<0.05 using a one-way ANOVA with Tukey Post-hoc analyses. Although the groups with a LBP history displayed greater decrements in relative back strength, time to exertion and perceptions of effort, compared to the uninjured group, spectral analyses indicated that fewer LBP participants exhibited fatigue of the assessed muscles, and no differences were found for joint position sense compared to the uninjured participants. These results imply that previously injured participants displayed exaggerated subjective responses to the lifting task, which can be attributed to “fear avoidance behaviour”.
An investigation of posture and manual materials handling as risk factors for low back pain in delivery driversAuthor Olanrewaju O. OkunribidoSource: Ergonomics SA : Journal of the Ergonomics Society of South Africa 28, pp 19 –27 (2016) http://dx.doi.org/10.4314/esa.v28i2.3More Less
The prevalence of low back pain symptoms, posture and manual materials handling among delivery drivers was investigated. Information about health history, driving experience, work postures and MMH was obtained from 49 male and 2 female persons who did intra-city deliveries and drove vehicles such as trucks, vans and Lorries, using the Aberdeen Vibration Exposure questionnaire. Twelve of the drivers were observed over a typical work period during which their work postures were recorded once every minute for an accumulated 1-hour period and the tasks performed and loads handled were noted. Data analysis was performed with the statistical package SPSS 10.1 for Windows. Results indicated that in a typical workday, intra-city delivery drivers are exposed to whole body vibration for only relatively short periods of time. For them, postural stress from twisting of the torso and frequent handling of loads, appear to be the main contributors to low back pain.
Source: Ergonomics SA : Journal of the Ergonomics Society of South Africa 28, pp 28 –48 (2016) http://dx.doi.org/10.4314/esa.v28i2.4More LessThe literature indicates that ‘green’ building is so focused on ensuring a sustainable design to create an environment for the final occupants that meets environmentally, healthy standards, that construction workers' health is being overlooked.Two descriptive surveys were conducted among general contractor members of the East Cape Masters Builders Association (ECMBA) and members of the Eastern Cape Institute of Architects (ECIA) using self-administered questionnaires.The salient findings are: contractors and architects identified there is a major need for ‘green’ building to address construction worker health and safety (H&S); workers become ill due to being exposed to health hazards; contractors indicate job security and unrealistic time for activities are the main factors contributing to workers experiencing stress; unsatisfactory working conditions, long working hours and demanding construction activities / tasks also contribute to workers becoming stressed; workers experience work related musculoskeletal disorders (WMSDs) due to strenuous work tasks, psychosocial factors, and hand arm vibration syndrome.Conclusions include: construction workers are exposed to many ergonomic and H&S hazards which can cause them to become ill, experience stress, experience WMSDs, experience injuries and in some cases death, and also be absent from work; construction worker H&S is still not viewed as ‘a value’ in terms of ‘green’ building, and there is a need for focus on ‘designing for construction ergonomics and H&S’.
A Modular and Adjustable Ptosis Crutch as a non-Ssurgical, low cost solution for elevating the upper eyelid in Myasthenia GravisSource: Ergonomics SA : Journal of the Ergonomics Society of South Africa 28, pp 49 –60 (2016) http://dx.doi.org/10.4314/esa.v28i2.5More Less
Myasthenia Gravis (MG) is an autoimmune disorder that affects the neuromuscular junction. MG is characterised by the fatigable weakness of skeletal muscles, commonly affecting the eye and facial muscles. Africans with MG, particularly juveniles, are more likely to develop treatment-resistance of their ocular muscles, including severe blepharoptosis. Blepharoptosis, or ptosis, describes the condition of a drooping upper eyelid(s). Surgical correction of ptosis is often contraindicated in MG patients. In these cases, a non-surgical solution to elevate the ptotic eyelid above the visual axis is required.
Objective: To design a ptosis crutch to elevate the ptotic eyelid(s) of MG patients. The crutch should be low cost, modular and adjustable in nature. Method: A bottom-up approach was followed for the design of the ptosis crutch. The requirements were defined according to patient, clinician and designer specifications. It underwent numerous iterations before the final design was manufactured, using 3D printing. 87 design failures were observed before the final design was realised. It was the design, test, fail, redesign cycle that lead to the discovery of a device that satisfied the requirements.
Results: The ptosis crutch attaches to the superior border of the spectacle frame and is adjustable along the x, y and z-axes to cater for the inter-individual variability of horizontal eye position, globe projection and the eyelid elevation required.
Conclusion: MG patient feedback on the ptosis crutch has shown a promising outcome for the device. Future work will include obtaining long term user feedback on the ptosis crutch.