| 1. |
- Jackson, Jennie A., et al.
(författare)
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Is what you see what you get? : Standard inclinometry of set upper arm elevation angles
- 2015
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Ingår i: Applied Ergonomics. - : Elsevier BV. - 0003-6870 .- 1872-9126. ; 47, s. 242-252
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Tidskriftsartikel (refereegranskat)abstract
- Previous research suggests inclinometers (INC) underestimate upper arm elevation. This study was designed to quantify possible bias in occupationally relevant postures, and test whether INC performance could be improved using calibration. Participants were meticulously positioned in set arm flexion and abduction angles between 0 degrees and 150 degrees. Different subject-specific and group-level regression models comprising linear and quadratic components describing the relationship between set and INC-registered elevation were developed using subsets of data, and validated using additional data. INC measured arm elevation showed a downward bias, particularly above 600. INC data adjusted using the regression models were superior to unadjusted data; a subject-specific, two-point calibration based on measurements at 0 and 900 gave results closest to the 'true' set angles. Thus, inclinometer measured arm elevation data required calibration to arrive at 'true' elevation angles. Calibration to a common measurement scale should be considered when comparing arm elevation data collected using different methods.
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| 2. |
- 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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| 3. |
- Larisch, Lisa-Marie, et al.
(författare)
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Effects of two randomized and controlled multi-component interventions focusing on 24-hour movement behavior among office workers: A compositional data analysis
- 2021
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Intervention studies aiming at changing movement behavior have usually not accounted for the compositional nature of time-use data. Compositional data analysis (CoDA) has been sug-gested as a useful strategy for analyzing such data. The aim of this study was to examine the effects of two multi-component interventions on 24-h movement behavior (using CoDA) and on cardi-orespiratory fitness among office workers; one focusing on reducing sedentariness and the other on increasing physical activity. Office workers (n = 263) were cluster randomized into one of two 6-month intervention groups, or a control group. Time spent in sedentary behavior, light-intensity, moderate and vigorous physical activity, and time in bed were assessed using accelerometers and diaries, both for 24 h in total, and for work and leisure time separately. Cardiorespiratory fitness was estimated using a sub-maximal cycle ergometer test. Intervention effects were analyzed using linear mixed models. No intervention effects were found, either for 24-h behaviors in total, or for work and leisure time behaviors separately. Cardiorespiratory fitness did not change significantly. Despite a thorough analysis of 24-h behaviors using CoDA, no intervention effects were found, nei-ther for behaviors in total, nor for work and leisure time behaviors separately. Cardiorespiratory fitness did not change significantly. Although the design of the multi-component interventions was based on theoretical frameworks, and included cognitive behavioral therapy counselling, which has been proven effective in other populations, issues related to implementation of and compliance with some intervention components may have led to the observed lack of intervention effect.
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| 4. |
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| 5. |
- Takala, Esa-Pekka, et al.
(författare)
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Systematic evaluation of observational methods assessing biomechanical exposures at work
- 2010
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Finnish Institute of Occupational Health; National Research Centre for the  . - 0355-3140 .- 1795-990X. ; 36:1, s. 3-24
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: This systematic review aimed to identify published observational methods assessing biomechanical exposures in occupational settings and evaluate them with reference to the needs of different users.Methods: We searched scientific databases and the internet for material from 1965 to September 2008. Methods were included if they were primarily based on the systematic observation of work, the observation target was the human body, and the method was clearly described in the literature. A systematic evaluation procedure was developed to assess concurrent and predictive validity, repeatability, and aspects related to utility. At least two evaluators independently carried out this evaluation.Results: We identified 30 eligible observational methods. Of these, 19 had been compared with some other method(s), varying from expert evaluation to data obtained from video recordings or through the use of technical instruments. Generally, the observations showed moderate-to-good agreement with the corresponding assessments made from video recordings; agreement was the best for large-scale body postures and work actions. Postures of wrist and hand as well as trunk rotation seemed to be more difficult to observe correctly. Intra- and inter-observer repeatability were reported for 7 and 17 methods, respectively, and were judged mostly to be moderate or good.Conclusions: With training, observers can reach consistent results on clearly visible body postures and work activities. Many observational tools exist, but none evaluated in this study appeared to be generally superior. When selecting a method, users should define their needs and assess how results will influence decision-making
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| 6. |
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| 7. |
- Mathiassen, Svend Erik, et al.
(författare)
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Bias and imprecision in posture percentile variables estimated from short exposure samples
- 2012
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Ingår i: BMC Medical Research Methodology. - : BioMed Central. - 1471-2288. ; 12:1, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundUpper arm postures are believed to be an important risk determinant for musculoskeletal disorder development in the neck and shoulders. The 10th and 90th percentiles of the angular elevation distribution have been reported in many studies as measures of neutral and extreme postural exposures, and variation has been quantified by the 10th-90th percentile range. Further, the 50th percentile is commonly reported as a measure of "average" exposure. These four variables have been estimated using samples of observed or directly measured postures, typically using sampling durations between 5 and 120 min.MethodsThe present study examined the statistical properties of estimated full-shift values of the 10th, 50th and 90th percentile and the 10th-90th percentile range of right upper arm elevation obtained from samples of seven different durations, ranging from 5 to 240 min. The sampling strategies were realized by simulation, using a parent data set of 73 full-shift, continuous inclinometer recordings among hairdressers. For each shift, sampling duration and exposure variable, the mean, standard deviation and sample dispersion limits (2.5% and 97.5%) of all possible sample estimates obtained at one minute intervals were calculated and compared to the true full-shift exposure value.ResultsEstimates of the 10th percentile proved to be upward biased with limited sampling, and those of the 90th percentile and the percentile range, downward biased. The 50th percentile was also slightly upwards biased. For all variables, bias was more severe with shorter sampling durations, and it correlated significantly with the true full-shift value for the 10th and 90th percentiles and the percentile range. As expected, shorter samples led to decreased precision of the estimate; sample standard deviations correlated strongly with true full-shift exposure values.ConclusionsThe documented risk of pronounced bias and low precision of percentile estimates obtained from short posture samples presents a concern in ergonomics research and practice, and suggests that alternative, unbiased exposure variables should be considered if data collection resources are restricted.
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| 8. |
- Toomingas, Allan, et al.
(författare)
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Variation between seated and standing/walking postures among male and female call centre operators
- 2012
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Ingår i: BMC Public Health. - London : Springer Science and Business Media LLC. - 1471-2458. ; 12, s. 154-
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of the present study was to assess variation in gross body posture amongst male and female call centre operators using whole-day registrations of seated and standing/walking periods, analyzed and described by a number of novel variables. Methods: Body postures, identified as either seated or standing/walking, were recorded using inclinometers throughout an entire work shift for 43 male and 97 female call centre operators at 16 call centres. Data were analyzed using an extensive set of variables describing occurrence of postures, switches between postures, posture similarities across the day, and compliance with posture recommendations. Results: The majority of the operators, both male and female, spent more than 80% of the shift in a seated posture. The average number of switches between seated and standing/walking or vice versa was 10.4 per hour. Female operators spent, on average, 11% of the day in periods of sustained sitting longer than 1 hour; male operators only 4.6% of the day (p=0.013). Only 38% of the operators followed current standard recommendations of having an uninterrupted break from seated work, lasting a minimum of 5minutes within a one hour of work and only 11% of operators had a 10 minute (or longer) uninterrupted break. Substantial variation between operators was observed in many variables. Since work tasks were essentially similar across operators and were expected to be similar across days, this indicates individual differences in working technique. Conclusions: The dominance of seated work for extended periods indicates that efforts should be made at call centres to introduce more gross physical variation during the work day. Appropriate and effective initiatives for realizing this intervention need to be identified
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| 9. |
- 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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| 10. |
- Wahlström, Jens, et al.
(författare)
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Upper arm postures and movements in female hairdressers across four full working days
- 2010
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press. - 0003-4878 .- 1475-3162. ; 54:5, s. 584-594
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To describe upper arm postures and movements among female hairdressers, including the variability between hairdressers, between days within hairdresser, and between tasks, as a basis for understanding the characteristics of exposures in the job, considering possible sources of variation and recovery, and discussing appropriate exposure assessment strategies.Methods: Data on upper arm postures were collected using inclinometers during four working days the same week from 28 female hairdressers working in 13 salons. Twenty of the hairdressers noted customer on and off times in a diary, to allow separate analyses of customer tasks (CT) and auxiliary non-customer tasks (AT), including breaks. For a number of posture and movement variables, mean values and variance components between subjects (BS) and within subjects between days (BD) were estimated using restricted maximum likelihood algorithms in one-way random effect models.Results: For the 20 hairdressers with diaries, CT accounted for 279 min (58%) (SDBS = 39 min and SDBD = 85 min) of the working day and AT and breaks for 207 min (42%) (SDBS = 46 min and SDBD = 88 min). The hairdressers worked with the right arm elevated >60° for 6.8% of the whole job (SDBS = 2.8% and SDBD = 2.0%). On average, the hairdressers worked with the right arm elevated >60° for 9.0% of the time during CT, compared to 3.7% during AT, resulting in a contrast between tasks of 0.35.Conclusions: Hairdressers may be at risk for developing musculoskeletal disorders in the neck and shoulders due to a considerable occurrence of highly elevated arms, especially during CT. On the other hand, we do not find reasons to classify hairdressing as a job with too little variation. Posture variability between days within hairdressers was in the same order of magnitude as that between hairdressers, suggesting that ‘typical’ workdays do not exist. The exposure contrast between CT and AT for variables describing elevated arm postures indicates that for these variables a simple task-based approach for estimating job exposure could be successful.
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