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In the transportation industry, human technicians are involved in weighing loads that are being transported. The procedure to weigh such loads requires the human operator to maintain the scales which are located in confined spaces, known as scale pits. Unfortunately, these scale pits were not designed with considerable attention to ergonomics or safety issues that may impact the technician. This paper examines the ergonomic concerns associated with the design of Scale-pits. Specifically, in this research, two case studies were used to assess the risk of falling due to loss of balance, as well as the perceived level of exertion and body discomfort experienced as a result of moving around in the small pit area. The studies conducted in this paper and previous research findings indicate that scale technicians are negatively impacted by the awkward posture positions that they have to assume when moving around and performing work in the restricted space of a scale pit. Also, the case studies analyzed in this paper indicate that scale technicians are likely to experience a decrease in their balance or stability as the work task parameters change which influences an increase in their perceived level of exertion. Also, these technicians may experience a higher perceived level of exertion and an increase in body discomfort due to the awkward postures that they have to assume when moving around and working in the restricted areas within the pit.

Carpal tunnel syndrome (CTS) remains one of the most commonly reported and studied work related musculoskeletal disorders. Categorical representations of exposures has been critical in identifying associations between risk factors and CTS, however, quantification of exposure-response relationships require using continuous exposure data. Also, few interactions between risk factors, especially between risk factor categories, have been investigated. The objectives of this study were to investigate the utility of using continuous exposure data and to identify interaction effects of risk factors, both within and between risk factor categories, for predicting CTS. A cross sectional study was performed at a fish processing facility in which 53 participants were evaluated during normal task performance. Due to task asymmetry, each hand was considered separately, providing 106 hands for analysis. Direct measurement and a questionnaire were used to quantify exposures to common occupational and personal risk factors. Stepwise logistic regression analysis was performed to identify three models for predicting CTS and assess predictive ability using: occupational risk factors only (three-way interactions considered), personal risk factors only (two-way interactions considered), and a mixed model considering two-way interactions across risk factor categories and previously identified significant interactions. Models including only occupational or personal risk factors were moderately accurate overall (73% and 77% respectively), but were not sensitive in differentiating between CTS cases and non-cases (39% and 33% respectively). The mixed model was found to be accurate (88%) and sensitive (78%), though only one interaction effect was included. The results of this study illustrate the importance of using continuous exposure data, especially in job tasks where exposures to occupational risk factors is similar, when differentiating between high and low risk job tasks.