Applied ergonomics
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The aim of this study was to determine whether body mass index (BMI) influences the risk of low back pain (LBP) in a population exposed to whole body vibration (WBV). For this a self-administered questionnaire was sent to 467 participants, driving occupational vehicles. Vibration measurements were performed according to ISO 2631-1 on a representative sample (n=30) of this population. ⋯ No significant increased risk was found for the onset of LBP with the increase of BMI, neither for the last 7 days (OR 1.02; 95% CI: 0.93-1.23) nor for the past 12 months LBP (OR 0.98; 95% CI: 0.89-1.09). Introducing the interaction with WBV exposure in the logistic regression model, did not result a significant increased risk in the onset of LBP-7 days (OR 0.97; 95% CI: 0.92-1.01) nor in the onset of LBP 12 months (OR 0.97; 95% CI: 0.93-1.01) either. Occupational participants exposed to WBV, with a high BMI do not have an increased risk for the development of LBP.
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This paper describes the observation of rearward movement (RM) of the heel following heel strike occurring during normal gait. Thirty-one participants recruited as part of a larger study on slip kinematics walked the length of an 8-m runway at a speed of 1.5 m/s. Several floor surfaces, presented dry and with contaminant, were used for the purpose of eliciting a wide range of small slip distances. ⋯ In trials where RMs were observed, forward slip distances were significantly less than for trials with no RMs, 2.17 (+/-3.87) mm vs. 12.58 (+/-10.71) mm, respectively. The time until the heel stopped moving during the post-heel strike period was not significantly different between RM and non-RM trials. Further investigation of this gait feature may improve understanding of normal gait patterns and may have implications for future slipmeter development.
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"Ergonomic" questionnaires are widely used in epidemiological field studies to study the association between workstation characteristics, work posture and musculoskeletal disorders among office workers. Findings have been inconsistent regarding the putative adverse effect of work postures. Underestimation of the true association might be present in studies due to misclassification of subjects to risk (i.e. exposed to non-neutral working postures) and no-risk categories (i.e. not exposed to non-neutral working postures) based on questionnaire responses. The objective of this study was to estimate the amount of misclassification resulting from the use of questionnaires. ⋯ The questionnaire collects reliable data on workstation characteristics and some individual characteristics during computer work (i.e. work movements and habits), but does not seem to be useful to collect data on work postures during computer work in epidemiological field studies among office workers.