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Elizabeth Bassey-Duke receives MSc with Dinstinction

Date Released: Wed, 15 April 2015 09:07 +0200

Miriam Mattison who was Elizabeth's supervisor for her MSc research, provides the following insight into the research project, which was field-based at local citrus farms in the Eastern Cape.

Elizabeth’s thesis title was: An ergonomics intervention study into the physiological, perceptual and productivity effects of three citrus harvesting bag designs in the Eastern Cape of South Africa- a combined laboratory and field approach.

During an ergonomics fieldtrip, Elizabeth identified that citrus harvesters were suffering from shoulder and back pains, which were attributed to the unilateral load carriage of the current harvesting bag they utilize, which places pressure on the load-carrying shoulder and promotes an asymmetrical working posture, particularly with a full load of citrus, which weighs around 12-13kg. Elizabeth set out to redesign this harvesting bag and ended up with two alternative options: one looked like the conventional one-sided shoulder strap bag, but had a hip belt added to it, thereby redirecting the weight of the citrus from the shoulder to the hips; the second design resembled a hiking backpack – the load was distributed over both shoulders (eliminating the asymmetry) and the hips.

To test whether her re-designs were indeed effective in reducing the stresses on the musculoskeletal system, she performed some extensive testing in the laboratory (muscle activity and perceived exertion). She also conducted some testing in the field on the actual harvesters to determine how they perceived the new bag designs, as well as assessing the new bags on productivity.

Interestingly, she found contradictory results: the backpack design, which yielded the most favourable results in the laboratory, was not accepted by harvesters, who preferred the shoulder-strap bag with the hip belt. This indicates that a direct transfer interventions devised in a laboratory to the field setting is not necessarily effective if social, educational, cultural and economic factors are not considered, particularly in the context of an industrially developing country.


Elizabeth pictured here with the asymmetric shoulder bag

Keba Thloahle (L) assisting Elizabeth (wearing backpack design)

The challenges faced: many !!! They ranged from design issues (for the bags), developing the laboratory simulation of the harvesting task, to testing during the field phase of the project. The field testing phase was probably the toughest due to the general challenges faced with intervention research, including communication barriers, unpredictable weather which interfered in the work processes and  workers’ reluctance to participate despite extensive explanations and demonstrations.