| 1. |
- Wahlström, Jens, et al.
(författare)
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Full-Shift Trunk and Upper Arm Postures and Movements Among Aircraft Baggage Handlers
- 2016
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 60:8, s. 977-90
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The present study assessed full-shift trunk and upper arm postural exposure amplitudes, frequencies, and durations among Swedish airport baggage handlers and aimed to determine whether exposures differ between workers at the ramp (loading and unloading aircraft) and baggage sorting areas.METHODS: Trunk and upper arm postures were measured using inclinometers during three full work shifts on each of 27 male baggage handlers working at a large Swedish airport. Sixteen of the baggage handlers worked on the ramp and 11 in the sorting area. Variables summarizing postures and movements were calculated, and mean values and variance components between subjects and within subject (between days) were estimated using restricted maximum likelihood algorithms in a one-way random effect model.RESULTS: In total, data from 79 full shifts (651h) were collected with a mean recording time of 495min per shift (range 319-632). On average, baggage handlers worked with the right and left arm elevated >60° for 6.4% and 6.3% of the total workday, respectively. The 90th percentile trunk forward projection (FP) was 34.1°, and the 50th percentile trunk movement velocity was 8° s(-1). For most trunk (FP) and upper arm exposure variables, between-subject variability was considerable, suggesting that the flight baggage handlers were not a homogeneously exposed group. A notable between-days variability pointed to the contents of the job differing on different days. Peak exposures (>90°) were higher for ramp workers than for sorting area workers (trunk 0.6% ramp versus 0.3% sorting; right arm 1.3% ramp versus 0.7% sorting).CONCLUSIONS: Trunk and upper arm postures and movements among flight baggage handlers measured by inclinometry were similar to those found in other jobs comprising manual material handling, known to be associated with increased risks for musculoskeletal disorders. The results showed that full-shift trunk (FP) and, to some extent, peak arm exposures were higher for ramp workers compared with sorting workers.
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| 2. |
- Trask, Catherine, et al.
(författare)
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Cost-efficient assessment of biomechanical exposure in occupational groups, exemplified by posture observation and inclinometry
- 2014
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 40:3, s. 252-265
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: This study compared the cost-efficiency of observation and inclinometer assessment of trunk and upper arm inclination in a population of flight baggage handlers, as an illustration of a general procedure for addressing the trade-off between resource consumption and statistical performance in occupational epidemiology.Methods: Trunk and upper arm inclination with respect to the line of gravity were assessed for 3 days on each of 27 airport baggage handlers using simultaneous recordings by inclinometers and video. Labour and equipment costs associated with data collection and data processing were tracked throughout. Statistical performance, in terms of the inverse of the standard deviation and root mean squared error of the group mean exposure, was computed from the variance components within and between workers, and bias (with inclinometer assumed to produce ‘correct’ inclination angles). The behavior of the trade-off between cost and efficiency with changed sample size, as well as with changed logistics for data collection and processing, was investigated using simulations.Results: At similar total costs, time spent at trunk and arm inclination angles greater than 60 degrees as well as 90th percentile arm inclination were estimated at higher precision using inclinometers, while median inclination and 90th percentile trunk inclination was determined more precisely using observation. This hierarchy persisted in a scenario where the study was immediately reproduced in another population, while inclinometry was more cost-efficient than observation for all three posture variables in a scenario where data were already collected and only needed to be processed. Observations showed to be biased relative to the –assumed to be correct – inclinometer data, and so inclinometry became the most cost-efficient option for all posture variables and irrespective of scenario when statistical performance was measured by bias and precision combined.Conclusions: Inclinometers were more cost-efficient in use than observation for two out of three posture metrics investigated when statistical performance was measured only in terms of precision. Since observations were biased, inclinometers consistently outperformed observation when both bias and precision were included in statistical performance. The presented general model for assessing cost-efficiency may be used for designing exposure assessment strategies with considerations not only to statistical criteria, but even to costs. The empirical data provide a specific basis for planning assessments of working postures in occupational groups.
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| 3. |
- Trask, Catherine, et al.
(författare)
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Data collection costs in industrial environments for three occupational posture exposure assessment methods
- 2012
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Ingår i: BMC Medical Research Methodology. - : BioMed Central. - 1471-2288. ; 12:1, s. 89-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Documentation of posture measurement costs is rare and cost models that do exist are generally nave. This paper provides a comprehensive cost model for biomechanical exposure assessment in occupational studies, documents the monetary costs of three exposure assessment methods for different stakeholders in data collection, and uses simulations to evaluate the relative importance of cost components. Methods: Trunk and shoulder posture variables were assessed for 27 aircraft baggage handlers for 3 full shifts each using three methods typical to ergonomic studies: self-report via questionnaire, observation via video film, and full-shift inclinometer registration. The cost model accounted for expenses related to meetings to plan the study, administration, recruitment, equipment, training of data collectors, travel, and onsite data collection. Sensitivity analyses were conducted using simulated study parameters and cost components to investigate the impact on total study cost. Results: Inclinometry was the most expensive method (with a total study cost of (sic) 66,657), followed by observation ((sic) 55,369) and then self report ((sic) 36,865). The majority of costs (90%) were borne by researchers. Study design parameters such as sample size, measurement scheduling and spacing, concurrent measurements, location and travel, and equipment acquisition were shown to have wide-ranging impacts on costs. Conclusions: This study provided a general cost modeling approach that can facilitate decision making and planning of data collection in future studies, as well as investigation into cost efficiency and cost efficient study design. Empirical cost data from a large field study demonstrated the usefulness of the proposed models.
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| 4. |
- Trask, Catherine, et al.
(författare)
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Data processing costs for three posture assessment methods
- 2013
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Ingår i: BMC Medical Research Methodology. - : BioMed Central. - 1471-2288. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Data processing contributes a non-trivial proportion to total research costs, but documentation of these costs is rare. This paper employed a priori cost tracking for three posture assessment methods (self-report, observation of video, and inclinometry), developed a model describing the fixed and variable cost components, and simulated additional study scenarios to demonstrate the utility of the model.METHODS: Trunk and shoulder postures of aircraft baggage handlers were assessed for 80 working days using all three methods. A model was developed to estimate data processing phase costs, including fixed and variable components related to study planning and administration, custom software development, training of analysts, and processing time.RESULTS: Observation of video was the most costly data processing method with total cost of € 30,630, and was 1.2-fold more costly than inclinometry (€ 26,255), and 2.5-fold more costly than self-reported data (€ 12,491). Simulated scenarios showed altering design strategy could substantially impact processing costs. This was shown for both fixed parameters, such as software development and training costs, and variable parameters, such as the number of work-shift files processed, as well as the sampling frequency for video observation. When data collection and data processing costs were combined, the cost difference between video and inclinometer methods was reduced to 7%; simulated data showed this difference could be diminished and, even, reversed at larger study sample sizes. Self-report remained substantially less costly under all design strategies, but produced alternate exposure metrics.CONCLUSIONS: These findings build on the previously published data collection phase cost model by reporting costs for post-collection data processing of the same data set. Together, these models permit empirically based study planning and identification of cost-efficient study designs.
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| 5. |
- Trask, Catherine, et al.
(författare)
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Modeling costs of exposure assessment methods in industrial environments
- 2012
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Ingår i: Work. - 1051-9815 .- 1875-9270. ; 41:supplement 1, s. 6079-6086
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Tidskriftsartikel (refereegranskat)abstract
- Documentation of posture measurement cost is rare and cost models that do exist are generally naive. This paper provides a comprehensive cost model for ergonomic research, documents the monetary costs of three exposure assessment methods (inclinometry, video observation, and self-report), and discusses cost components. Trunk and shoulder posture were assessed for 27 aircraft baggage handlers for 3 full shifts each using three methods typical to ergonomics: self-report via questionnaire, observation via video film, and full-shift inclinometer registration. The model accounted for costs related to meetings to plan the study, administration, recruitment, equipment, training of data collectors, travel, and onsite data collection. Findings show that inclinometer was the most expensive method, followed by observation and then self report; the majority of costs (90%) were borne by researchers. Study design parameters such as sample size, measurement scheduling and spacing, concurrent measurements, location and travel, and equipment acquisition were shown to have wide-ranging impacts on costs. This study provided empirical cost data for use in cost models that can facilitate decision making and planning of future studies, and can be used to investigate cost efficiency in future studies.
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