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Tittel [sv]
Kostnadseffektiv modellering av fysisk arbetsbelastning - en empirisk studie av arbetsställningar i industrin
Tittel [en]
Cost-efficient modeling of physical work load - an empirical study of work postures in industry
Abstract [sv]
Hos både forskare och praktiker som mäter fysisk belastning i arbetslivet finns behov av att samla in så mycket information som möjligt i förhållande till de investerade resurserna. Man vill använda sig av datainsamlingsmetoder som ger tillförlitliga data till en låg kostnad. En föga beforskad strategi för att åstadkomma det är att identifiera enkla och billiga variabler om arbetet och arbetsbelastningen som kan användas för att uppskatta resultatet av dyrare, mer komplicerade, mätningar av fysisk belastning. I projektet kommer därför resurskrävande direkta mätningar av fysisk belastning i form av arbetsställning att göras på personalen vid ett företag, samtidigt som lätt åtkomlig information samlas in om personalens upplevda belastning, objektiva belastningsfaktorer och verksamheten inom organisationen. I anslutning till detta kommer kostnaden för att samla in de olika datatyperna att beräknas. De insamlade data kommer sedan att användas för att bygga statistiska regressionsmodeller av förhållandet mellan de kostsamma direkta mätningarna av arbetsställning och de billigare indirekta måtten på belastning. Modellerna kommer att utvärderas dels med avseende på deras förmåga att prediktera den uppmätta arbetsställningen, och dels med avseende på den kostnad som det innebär att använda dem. Det kan medföra att den modell som ger det i statistisk mening bästa estimatet av arbetsställningen inte nödvändigtvis är den optimala modellen att arbeta med ur resurssynpunkt. Om kostnaderna för insamling av de nödvändiga variablerna är för stora i förhållande till modellens statistiska prestanda, så kan en modell med lägre förklaringsgrad och billigare variabler vara mer tilltalande att använda i praktiken. Projektet förväntas leda till praktiskt tillämpbar kunskap om optimering av resurser vid mätning av arbetsställning i arbetslivet, för såväl forskare som praktiker med behov av att samla in sådana data.
Publikasjoner (6 av 6) Visa alla publikasjoner
Trask, C., Mathiassen, S. E., Rostami, M. & Heiden, M. (2017). Observer variability in posture assessment from video recordings: the effect of partly visible periods. Applied Ergonomics, 60, 275-281
Åpne denne publikasjonen i ny fane eller vindu >>Observer variability in posture assessment from video recordings: the effect of partly visible periods
2017 (engelsk)Inngår i: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 60, s. 275-281Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Observers rank partly visible postures on video frames differently than fully visible postures, but it’s not clear if this is due to differences in observer perception. This study investigated the effect of posture visibility on between-observer variability in assessments of trunk and arm posture.  Trained observers assessed trunk and arm postures from video recordings of 84 pulp mill shifts using a work sampling approach; postures were also categorized as ‘fully’ or ‘partly’ visible.  Between-worker, between-day, and between-observer variance components and corresponding confidence intervals were calculated. Although no consistent gradient was seen for the right upper arm, trunk posture showed smaller between-observer variance when all observers rated a posture as fully visible. This suggests that, partly- visible data, especially when observers disagree as to the level of visibility, introduces more between-observer variability when compared to fully visible data.  Some previously-identified differences in daily posture summaries may be related to this phenomenon.

Emneord
Observation, inter-rater agreement, posture, exposure assessment, pulp mill
HSV kategori
Identifikatorer
urn:nbn:se:hig:diva-21286 (URN)10.1016/j.apergo.2016.12.009 (DOI)000394485400028 ()28166886 (PubMedID)2-s2.0-85007047071 (Scopus ID)
Forskningsfinansiär
Forte, Swedish Research Council for Health, Working Life and Welfare, 2009-1761Forte, Swedish Research Council for Health, Working Life and Welfare, 2010-00748
Merknad

Funding agency:

Canada Research Chairs program

Tilgjengelig fra: 2016-02-29 Laget: 2016-02-29 Sist oppdatert: 2019-10-04bibliografisk kontrollert
Heiden, M., Garza, J., Trask, C. & Mathiassen, S. E. (2017). Predicting directly measured trunk and upper arm postures in paper mill work from administrative data, workers’ ratings and posture observations. Annals of Work Exposures & Health, 61(2), 207-217
Åpne denne publikasjonen i ny fane eller vindu >>Predicting directly measured trunk and upper arm postures in paper mill work from administrative data, workers’ ratings and posture observations
2017 (engelsk)Inngår i: Annals of Work Exposures & Health, ISSN 2398-7308, Vol. 61, nr 2, s. 207-217Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Introduction: A cost-efficient alternative to measuring working postures directly could be to build statistical models for predicting results of such measurements from cheaper data, and apply these models to samples in which only the latter data are available. The present study aimed to build and assess the performance of statistical models predicting inclinometer-assessed trunk and arm posture among paper mill workers. Separate models were built using administrative data, workers’ ratings of their exposure, and observations of the work from video recordings as predictors.

Methods: Trunk and upper arm postures were measured using inclinometry on 28 paper mill workers during three work shifts each. Simultaneously, the workers were video filmed, and their postures were assessed by observation of the videos afterwards. Workers’ ratings of exposure, and administrative data on staff and production during the shifts were also collected. Linear mixed models were fitted for predicting inclinometer-assessed exposure variables (median trunk and upper arm angle, proportion of time with neutral trunk and upper arm posture, and frequency of periods in neutral trunk and upper arm inclination) from administrative data, workers’ ratings, and observations, respectively. Performance was evaluated in terms of Akaike information criterion, proportion of variance explained (R2), and standard error of the model estimate (SE). For models performing well, validity was assessed by bootstrap resampling.

Results: Models based on administrative data performed poorly (R2≤15%) and would not be useful for assessing posture in this population. Models using workers’ ratings of exposure performed slightly better (8%≤R2≤27% for trunk posture; 14%≤R2≤36% for arm posture). The best model was obtained when using observational data for predicting frequency of periods with neutral arm inclination. It explained 56% of the variance in the postural exposure, and its SE was 5.6. Bootstrap validation of this model showed similar expected performance in other samples (5th-95th percentile: R2=45-63%; SE=5.1-6.2).

Conclusions: Observational data had a better ability to predict inclinometer-assessed upper arm exposures than workers’ ratings or administrative data, but they are typically more expensive to obtain. The results encourage comparisons of the cost-efficiency of modeling based on administrative data, workers’ ratings, and observation.

Emneord
exposure assessment, statistical modeling, musculoskeletal epidemiology
HSV kategori
Identifikatorer
urn:nbn:se:hig:diva-21448 (URN)10.1093/annweh/wxw026 (DOI)000405566900008 ()28395353 (PubMedID)2-s2.0-85017305651 (Scopus ID)
Forskningsfinansiär
Forte, Swedish Research Council for Health, Working Life and Welfare, 2010-0748Forte, Swedish Research Council for Health, Working Life and Welfare, 2009-01761
Tilgjengelig fra: 2016-04-29 Laget: 2016-04-29 Sist oppdatert: 2019-10-04bibliografisk kontrollert
Heiden, M., Garza, J., Trask, C. & Mathiassen, S. E. (2016). Cost-efficient assessment of variation in arm posture during paper mill work. In: : . Paper presented at Ninth International Conference on the Prevention of Work-Related Musculoskeletal Disorders (PREMUS), June 20-23, 2016, Toronto, Canada.
Åpne denne publikasjonen i ny fane eller vindu >>Cost-efficient assessment of variation in arm posture during paper mill work
2016 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

Background. Arm posture is a recognized risk factor for occupational upper extremity musculoskeletal disorders and thus often assessed in research and practice. Posture assessment methods differ in cost, feasibility and, perhaps, bias. An attractive approach could be to build statistical models for predicting results of expensive direct measurements of arm posture from cheaper or more accessible data, and apply them to large samples in which only the latter data are available. We aimed to build and assess the performance of such prediction models in a random sample of paper mill workers.

Methods. 28 workers were recruited to the study, and their upper arm postures were measured during three full work shifts using inclinometers. Simultaneously, the workers were video filmed, and their arm posture and gross body posture were assessed by observing the video afterwards. Models for predicting the inclinometer-assessed duration (proportion of time) and frequency (number/min) of periods spent in neutral right arm posture (<20°) were fitted using subject and observer as random factors, measured shift (1, 2 or 3) as fixed factor, and either observed time in neutral right arm angle or observed gross body posture as predictor.

Results. For the proportion of time spent in neutral arm posture, the best performance was achieved by using observed gross body posture as predictor (explained variance: R2=26%; standard error: SE=9.8). For the frequency of periods spent in neutral arm posture, the corresponding model fit was R2=60% and SE=5.6. Bootstrap resample validation of the latter model showed an expected performance in other samples of R2=59-60% and SE=5.5-5.6 (5th-95th percentile).

Discussion. Surprisingly, we found that observed gross body posture was a better predictor of variation in arm posture than observed arm angles. The findings suggest that arm posture during paper mill work can be cost-efficiently assessed using simple observations.

HSV kategori
Identifikatorer
urn:nbn:se:hig:diva-21909 (URN)
Konferanse
Ninth International Conference on the Prevention of Work-Related Musculoskeletal Disorders (PREMUS), June 20-23, 2016, Toronto, Canada
Forskningsfinansiär
Forte, Swedish Research Council for Health, Working Life and Welfare, 2010-00748
Tilgjengelig fra: 2016-06-23 Laget: 2016-06-23 Sist oppdatert: 2019-10-04bibliografisk kontrollert
Garza, J., Mathiassen, S. E. & Heiden, M. (2016). Reliability of using observations when assessing different posture variables. In: : . Paper presented at Ninth International Conference on the Prevention of Work-Related Musculoskeletal Disorders (PREMUS), Toronto, June 20-23, 2016.
Åpne denne publikasjonen i ny fane eller vindu >>Reliability of using observations when assessing different posture variables
2016 (engelsk)Konferansepaper, Oral presentation with published abstract (Fagfellevurdert)
Abstract [en]

Background. Working in extreme postures has been identified as a risk factor for musculoskeletal symptoms. Directly measuring work postures is considered to be the most accurate approach for assessing these exposures, but it is often not feasible to directly measure posture due to time or budget constraints. Alternatively, direct measurements of postures can be predicted based on observations of workers’ postures. Since observers are known to differ in posture ratings, it may, however, be necessary to develop calibration procedures for each specific observer.

Methods. Arm and back postures of a random sample of 28 paper mill workers were measured via inclinometry and also were assessed by three observers from videos. Linear models with participant number and observer as random effects were resolved to assess whether or not observed postures were associated with the corresponding inclinometer values and if the effect of observer on slope and intercept was significant (p<0.05). The variance explained by these models was compared to the variance explained by corresponding linear models yet with observer entered as a fixed effect (i.e. allowing different slopes and intercepts for different observers).

Results. For all postures, the variance explained was similar when using observer as a fixed compared to a random effect (R-squared ranging from 0.41 to 0.56 for observer as fixed or random effect). Throughout, participant was the major source of variance.

Discussion. Our findings of similar amounts of variance explained when using observer as a fixed compared to a random effect for all postures indicates that calibration models developed for each individual observer may not necessarily perform better than a general calibration applying to any observer. Since posture observations explained only a small proportion of directly measured posture variance, observation may not be very useful in this setting

HSV kategori
Identifikatorer
urn:nbn:se:hig:diva-21915 (URN)
Konferanse
Ninth International Conference on the Prevention of Work-Related Musculoskeletal Disorders (PREMUS), Toronto, June 20-23, 2016
Forskningsfinansiär
Forte, Swedish Research Council for Health, Working Life and Welfare, 2010-00748
Tilgjengelig fra: 2016-06-23 Laget: 2016-06-23 Sist oppdatert: 2019-10-04bibliografisk kontrollert
Trask, C., Mathiassen, S. E., Rostami, M. & Heiden, M. (2016). Variance components of observed postural exposure - the effect of partly visible periods. In: : . Paper presented at Ninth International Conference on the Prevention of Work-Related Musculoskeletal Disorders (PREMUS), June 20-23, 2016, Toronto, Canada.
Åpne denne publikasjonen i ny fane eller vindu >>Variance components of observed postural exposure - the effect of partly visible periods
2016 (engelsk)Konferansepaper, Oral presentation with published abstract (Fagfellevurdert)
Abstract [en]

Background. Previous studies have shown that video-based observation of postures that are only partly visible leads to different daily summary values than when postures are fully visible. However, the source of these differences is unclear. The purpose of this study was to estimate the between-observer variance of trunk and arm posture estimates (relative to within- and between-worker variance), and to investigate the effect of visibility on this observer variability of trunk and arm postural exposure estimates.

Methods. Video recordings were made of 28 pulp mill workers for three full shifts each. Trunk and arm postures were then estimated by trained observers using a work sampling approach; posture images were also assessed as being “fully” or “partly” visible. REML techniques were used to estimate the between-worker, between-day and betweenobserver components of variance at different visibility levels; Wald-based confidence intervals and p-values were used to determine sources of variation.

Results. Estimates of partly visible postures (as agreed upon by all observers) were lower than fully visible postures. However, more than 90% of trunk observations and 85% of arm observations did not have full agreement on visibility between observers. Right upper arm posture showed smaller between-observer variance when all observers rated a posture to be fully visible, as compared to all observers agreeing it was only partly visible. This suggests partly visible data introduces more methodological (i.e. between-observer) variability when compared to fully visible data. However, no significant differences in between-observer variability were found for the trunk, suggesting that other factors explain the reported differences in estimated postures between fully and partly visible data in this case.

Discussion. Future studies involving concurrent direct measurement would determine whether there is a true difference in posture between partly visible and fully visible periods, or whether the difference between fully and partly visible periods are related to observer performance.

HSV kategori
Identifikatorer
urn:nbn:se:hig:diva-21891 (URN)
Konferanse
Ninth International Conference on the Prevention of Work-Related Musculoskeletal Disorders (PREMUS), June 20-23, 2016, Toronto, Canada
Forskningsfinansiär
Forte, Swedish Research Council for Health, Working Life and Welfare, 2010-00748
Tilgjengelig fra: 2016-06-23 Laget: 2016-06-23 Sist oppdatert: 2019-10-04bibliografisk kontrollert
Heiden, M. & Mathiassen, S. E. (2015). Prediction of trunk and upper arm postures in paper mill workers by statistical modelling: an empirical validation study. In: Gitte Lindgaard & Dave Moore (Ed.), Proceedings of the 19th Triennial Congress of the International Ergonomics Association, Melbourne 9-14 August 2015: . Paper presented at 19th Triennial Congress of the International Ergonomics Association, 9-14 August 2015, Melbourne, Australia.
Åpne denne publikasjonen i ny fane eller vindu >>Prediction of trunk and upper arm postures in paper mill workers by statistical modelling: an empirical validation study
2015 (engelsk)Inngår i: Proceedings of the 19th Triennial Congress of the International Ergonomics Association, Melbourne 9-14 August 2015 / [ed] Gitte Lindgaard & Dave Moore, 2015Konferansepaper, Publicerat paper (Fagfellevurdert)
HSV kategori
Identifikatorer
urn:nbn:se:hig:diva-20117 (URN)
Konferanse
19th Triennial Congress of the International Ergonomics Association, 9-14 August 2015, Melbourne, Australia
Forskningsfinansiär
Forte, Swedish Research Council for Health, Working Life and Welfare, 2010-00748
Tilgjengelig fra: 2015-08-18 Laget: 2015-08-18 Sist oppdatert: 2019-10-04bibliografisk kontrollert
Principal InvestigatorHeiden, Marina
Koordinerande organisasjon
Högskolan i Gävle
Forskningsfinansiär
Tidsperiod
2011-01-01 - 2013-12-31
Identifikatorer
DiVA, id: project:304Prosjekt id: 2010-00748_Forte

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