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  • 701.
    Toomingas, Allan
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Hagberg, Mats
    Occupational & Environmental Medicine University of Gothenburg.
    Heiden, Marina
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Richter, Hans
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Westergren, Karl Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Wigaeus Tornqvist, Ewa
    School of Health Sciences, Jönköping University.
    Incidence and risk factors for symptoms from the eyes among professional computer users2012In: Work: A journal of Prevention, Assesment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 41, no Suppl. 1, p. 3560-3562Article in journal (Refereed)
    Abstract [en]

    Personal computers are used by a majority of the working population in their professions. Little is known about risk-factors for incident symptoms from the eyes among professional computer users. The aim was to study the incidence and risk-factors for symptoms from the eyes among professional computer users. This study is a part of a comprehensive prospective follow-up study of factors associated with the incidence of symptoms among professional computer users. 1531 computer users of different professions at 46 companies were invited, whereof 1283 answered a baseline questionnaire (498 men; 785 women) and 1246 at least one of 10 monthly follow-up questionnaires. The computer work-station and equipment were generally of a good standard. The majority used CRT displays. During the follow-up period 329 subjects reported eye symptoms. The overall incidence rate in the whole study group was 0.38 per person-year, 0.23 in the subgroup of subjects who were symptom free at baseline and 1.06 among subjects who reported eye symptoms at baseline. In the bivariate analyses significant associations were found with all explanatory variables, except BMI. The reduced multivariate model showed significant associations with extended computer work, visual discomfort (dose-response), eye symptoms at baseline (higher risk), sex (women=higher risk) and nicotine use. The incidence of eye problems among professional computer users is high and related to both individual and work-related factors.

  • 702.
    Toomingas, Allan
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Karolinska Institutet.
    Hagberg, Mats
    Göteborgs Universitet.
    Heiden, Marina
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Richter, Hans
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Westergren, Karl-Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Wigaeus Tornqvist, Ewa
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Jönköping University, School of Health Sciences.
    Risk factors, incidence and persistence of symptoms from the eyes among professional computer users2014In: Work: A journal of Prevention, Assesment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 47, no 3, p. 291-301Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Symptoms from the eyes are common among computer users. Knowledge is scarce about these problems, however.

    OBJECTIVES:

    The aim was to study risk-factors, incidence and persistence of eye-symptoms among professionally active computer users.

    METHODS:

    This was a questionnaire based prospective study where 1283 males and females from different professions and companies answered a baseline questionnaire about individual factors and working conditions, e.g. duration of daily computer work, comfort of screen work, psychosocial factors. Subjects were at baseline and 10 follow-ups asked about the number of days with eye-symptoms during the preceding month.

    RESULTS:

    The incidence-rate of symptoms persisting minimum three days was 0.38/person-year. A multivariate Hazard-ratio model showed significant associations with extended continuous computer work, tasks with high demands on eye-hand coordination, low level of control, visual discomfort, female sex and nicotine use. Eye-symptoms at baseline was a strong risk factor for new symptoms.

    CONCLUSION:

    The incidence of eye-symptoms among professional computer users is high and related to both individual and work-related factors. The organization of computer work should secure frequent breaks from near-work at the computer screen. The severity of vision-related problems could in field studies be quantified by asking for the persistence of symptoms.

  • 703. Toomingas, Allan
    et al.
    Mathiassen, Svend Erik
    University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Variation in gross body posture during call centre work2009In: Proceedings of the IEA2009 conference, Beijing, 2009Conference paper (Refereed)
  • 704.
    Toomingas, Allan
    et al.
    Karolinska Institutet.
    Mathiassen, Svend Erik
    University of Gävle, Centre for Musculoskeletal Research.
    Wigaeus Tornqvist, Ewa
    Skolan för teknik och Hälsa, Kungliga Tekniska Högskolan.
    Arbete, arbetsliv, arbetslivsfysiologi2008In: Arbetslivsfysiologi / [ed] Allan Toomingas, Svend Erik Mathiassen, Ewa Wigaeus Tornqvist, Lund: Studentlitteratur, 2008, p. 17-38Chapter in book (Other academic)
  • 705.
    Toomingas, Allan
    et al.
    Karolinska Institutet.
    Mathiassen, Svend ErikUniversity of Gävle, Centre for Musculoskeletal Research.Wigaeus Tornqvist, EwaKungliga Tekniska Högskolan, Skolan för teknik och hälsa.
    Arbetslivsfysiologi2008Collection (editor) (Other academic)
  • 706.
    Toomingas, Allan
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend ErikUniversity of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.Wigaeus Tornqvist, EwaSchool of Health Sciences, Jönköping.
    Occupational Physiology2012Collection (editor) (Other academic)
    Abstract [en]

    In a clear and accessible presentation, Occupational Physiology focuses on important issues in the modern working life. Exploring major public health problems such as musculoskeletal disorders and stress, this book explains connections between work, well-being, and health based on up-to-date research in the field. It provides useful methods for risk assessments and guidelines on arranging a good working life from the perspective of the working individual, the company, and society as a whole.

    The book focuses on common, stressful situations in different professions in work life. Reviewing bodily demands and reactions in eight selected common but contrasting job types, the book explains relevant physiology in a novel way. Rather than being structured according to organs in the body, the book accepts the complex physiology of typical jobs and uses this as an entry. In addition to physiological facts, the book discusses risk factors for disorders and gives ideas on how to organize and design work and tasks so as to optimize health, work ability, and productivity.

    Although many books cover physiology, they are based on a traditional anatomical structure (e.g., addressing the physiology of the cardiovascular system, the gastrointestinal system, and so forth) and require readers to synthesize this knowledge into real-life complex applications. Occupational Physiology is, instead, structured around a number of typical jobs and explains their physiology, as complex as they may be. This approach, while still presenting the physiology needed to understand occupational life, demonstrates how to use this information in situations encountered in practice.

  • 707.
    Toomingas, Allan
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Wigaeus Tornqvist, Ewa
    School of Health Sciences, Jönköping.
    Work, Working Life, Occupational Physiology2012In: Occupational Physiology / [ed] Toomingas A, Mathiassen SE, Wigaeus Tornqvist E, Boca Raton, FL: CRC Press, 2012, p. 1-18Chapter in book (Other academic)
  • 708.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. University of Saskatchewan, College of Medicine, Centre for Health & Safety in Agriculture, Saskatoon, SK S7N 0W8, Canada.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Jackson, Jennie
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Wahlström, Jens
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Umea University, Department of Public Health & Clinical Medical Occupational & Environmental Medicine, SE-90185 UmeåSweden.
    Data processing costs for three posture assessment methods2013In: BMC Medical Research Methodology, ISSN 1471-2288, E-ISSN 1471-2288, Vol. 13, no 1, p. 124-Article in journal (Refereed)
    Abstract [en]

    Objectives. 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 31,433, 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.

  • 709.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Rostami, Mehdi
    School of Public Health, University of Saskatchewan, Canada.
    Partly visible periods in posture observation from video: prevalence and effect on summary estimates of postures in the job2015In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 49, p. 63-69Article in journal (Refereed)
    Abstract [en]

    We investigated the extent to which observers rate clearly visible postures on video differently from postures that are only partly visible, and whether this would have an effect on full-shift posture summaries. Trunk and upper arm postures were observed from 10,413 video frames representing 80 shifts of baggage handling; observers reported whether postures were fully or only partly visible.  Postures were summarized for each shift into several standard metrics using all available data, only fully visible frames, or only partly visible frames. 78% of trunk and 71% of upper arm postural observations were inferred.  When based on all data, mean and 90th percentile trunk postures were 1.3° and 5.4° lower, respectively, than when based only on fully visible situations.  For the arm; differences in mean and 90thpercentile were 2.5° and 8.1°.  Daily posture summaries can, thus, be significantly influenced by whether partly visible postures are included or not

  • 710.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Rostami, Mehdi
    Collaborative Biostatistics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
    Heiden, Marina
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Observer variability in posture assessment from video recordings: the effect of partly visible periods2017In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 60, p. 275-281Article in journal (Refereed)
    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.

  • 711.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Rostami, Mehdi
    Collaborative Biostatistics Program, School of Public Health, University of Saskatchewan.
    Heiden, Marina
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Variance components of observed postural exposure - the effect of partly visible periods2016Conference paper (Refereed)
    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.

  • 712.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Teschke, K
    University of British Columbia School of Population and Public Health, Vancouver, Canada.
    Koehoorn, M W
    University of British Columbia School of Population and Public Health, Vancouver, Canada.
    Price versus precision cost efficiency in trunk posture observation (Poster)2010Conference paper (Refereed)
    Abstract [en]

    Aims There is a long-acknowledged tradeoff between precision and cost of exposure assessment strategies (Winkel and Mathiassen, 1994), but a dearth of literature quantifying this tradeoff. This study compares different sampling strategies for trunk posture observation with respect to monetary costs and statistical efficiency. Methods Experts observed 126 workers in heavy industry during full work shifts, with repeated measures on 76% of workers. The observed percentage of time spent with trunk flexed more than 60 degrees was recorded and summarized for each work day using the Back-EST sampling method (Village et al 2009). A model of costs associated with the data sampling strategy was developed using previously published data (Trask et al 2007), accounting for the costs of recruiting companies and workers, and of observing full work shifts. Statistical performance was described as standard error of the mean (SEM). Post hoc, a selection of sampling strategies were simulated to demonstrate the empirical trade-off between cost and efficiency for different sampling strategies. Results: Figure 1 shows the family of curves resulting when 1 to 10 workers are measured 1 to 4 times within a single company. The SEM declines steeply for the first few additional subjects, while further subjects increase costs considerably with no substantial improvements in precision. Adding repeated measures generally increased costs with smaller gains in precision. Discussion/conclusions: This study informs design of posture observation sampling campaigns; the ‘mesh’ of sampling strategies in the figure demonstrates the maximum precision level that can be achieved for a given cost, as well as the minimum cost for a given level of precision. This allows researchers to make informed decisions on the use of limited resources when designing ergonomic studies

  • 713.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Teschke, K
    University of British Columbia School of Population and Public Health, Vancouver, Canada.
    Koehoorn, M.W
    University of British Columbia School of Population and Public Health, Vancouver, Canada.
    More for the Money: Cost Efficiency in Trunk Posture Observation2010In: Canadian Association for Research in Work and Health, Toronto, Canada, 2010Conference paper (Refereed)
    Abstract [en]

    Objectives:In a climate of scarce research funds, cost-effective exposure assessment becomes more critical. There is a long-acknowledged tradeoff between precision and cost of exposure assessment methods (Winkel and Mathiassen, 1994) that is seldom quantified.The purpose of this study was to compare different sampling strategies for observed trunk posture and determinewhich is the most cost-effective.Knowing the price-performance tradeoffs of observational exposure assessment can help researchers make the most of limited funds.Methods(maximum 150 words)Trunk posture data was observed by trained experts during full work shifts on 126 workers in heavy industry, with repeated measures on 76% of workers. The observed percentage of time spent with trunk flexed more than 60 degrees was recorded and summarized for each work day using the Back-EST sampling method (Village et al 2009). A cost model was developed using previously published cost data (Trask et al 2007) to account for the costs of recruiting companies, workers, and making a full-shift observation of trunk posture. Precision was described in terms of the standard error of the group mean (SEM), using equations from Samuels (1985) that account for multiple measures within companies and workers. Changes in cost efficiency were calculated for sampling strategies employing different combinations of the following: 1-4 companies, 1-12 workers, and 1-4 measures per worker. The case of one recruited company is highlighted here as an example.Results:(maximum 100 words)The SEM declines steeply for the first few additional subjects, while further subjects increase costs considerably with no substantial improvements in precision. Adding repeated measures generally increased costs with smaller gains in precision. In a single-company example, measuring 6 subjects twice (12 measurements total) yields SEM = 0.76 and costs $3929. The same number of measurements can cost up to $4505 with 12 subjects and no repeats, improving the SEM to 0.75. However, increased cost does not always deliver gains in precision; an SEM of 0.76 can cost up to $5545 when 5 subjects are measured 4 times.Conclusions(maximum 100 words)The total number of measurements has been used as a metric for cost optimization in previous investigations (Lemasters et al 1996). However, an equal number of measurements can have different costs depending on how they are allocated due to recruitment costs. Such cost-efficiency information allows researchers to make informed decisions on the use of limited resources when designing ergonomic studies; either determining the maximum precision level that can be achieved for a given cost, or the minimum cost for a given level of precision.

  • 714.
    Trask, Catherine
    et al.
    Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Wahlström, Jens
    Department of Public Health & Clinical Medicine, Umeå University.
    Getting what we pay for: comparing the cost efficiency of direct and observed trunk posture methods2013In: Eighth International Conference on Prevention of Work-related Musculoskeletal Disorders; abstracts, 2013, p. 177-Conference paper (Refereed)
  • 715.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Wahlström, Jens
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Cost-efficient assessment of biomechanical exposure in occupational groups, exemplified by posture observation and inclinometry2014In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, E-ISSN 1795-990X, Vol. 40, no 3, p. 252-265Article in journal (Refereed)
    Abstract [en]

    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.

  • 716.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Wahlström, Jens
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Rezagholi, Mahmoud
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Data collection costs in industrial environments for three occupational posture exposure assessment methods2012In: BMC Medical Research Methodology, ISSN 1471-2288, E-ISSN 1471-2288, Vol. 12, p. 89-Article in journal (Refereed)
    Abstract [en]

    Background. Documentation of posture measurement costs is rare and cost models that do exist are generally naïve. 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.  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. Inclinometery was the most expensive method (with a total study cost of € 66,657), followed by observation (€ 55,369) and then self report (€ 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 modelling 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.

  • 717.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Wahlström, Jens
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Rezagholi, Mahmoud
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Modeling costs of exposure assessment methods in industrial environments2012In: Work: A journal of Prevention, Assesment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 41, p. 6079-6086Article in journal (Refereed)
    Abstract [en]

    Documentation of posture measurement cost is rare and cost models that do exist are generally naïve. 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 wideranging 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

  • 718.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Teschke, Kay
    University of British Columbia, Canada.
    Morrison, Jim
    Simon Fraser University, Canada.
    Johnson, Pete
    University of Washington, USA.
    Village, Judy
    University of British Columbia, Canada.
    Koehoorn, Mieke
    University of British Columbia, Canada.
    EMG estimated mean, peak, and cumulative spinal compression of workers  in five heavy industries2010In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 40, no 4, p. 448-454Article in journal (Refereed)
    Abstract [en]

    The goal of this study was to explore the use of compression-normalized electromyography (CNEMG) to estimate mean, peak, and cumulative loading of the low back in workers of five heavy industries using and to compare the estimates to the NIOSH guidelines. Full-shift (5.5 to 10.3 hours) EMG measurements were collected from 105 workers and transformed into units of low back compressive force (Newtons). The mean, peak, and cumulative CNEMG as well as the percentage of work time spent above 3400 N and 6800 N thresholds were calculated. Mean CNEMG (sd) was 1564 N (796), peak was 2721 (1545), and cumulative was 38 MN.sec (22). Mean time spent above the NIOSH threshold of 3400 N was on average 6.3% of shift, while mean time spent above the 6400 N threshold was around 1%. CNEMG allowed the feasible investigation of tasks and jobs that would be virtually impossible with more advanced biomechanical methods and represents a more objective measure of exposure than observation or self-report. CNEMG is a relatively new method with methodological limitations, however, CNEMG's strength may be as an objective, relative measure of exposure in studies where low back EMG is collected in a relatively systematic and structured manner.

  • 719.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Teschke, Kay
    School of Environmental Health, University of British Columbia, Vancouver, Canada; School of Population and Public Health, University of British Columbia, Vancouver, Canada.
    Morrison, Jim
    Simon Fraser University School of Kinesiology, Burnaby, Canada.
    Johnson, Peter
    Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, United States.
    Koehoorn, Mieke
    School of Environmental Health, University of British Columbia, Vancouver, Canada; School of Population and Public Health, University of British Columbia, Vancouver, Canada.
    Optimising sampling strategies: components of low-back EMG variability in five heavy industries2010In: Occupational and Environmental Medicine, ISSN 1351-0711, E-ISSN 1470-7926, Vol. 67, no 12, p. 853-860Article in journal (Refereed)
    Abstract [en]

    Background Direct/ measurement of work activities iscostly, so researchers need to distribute resourcesefficiently to elucidate the relationships betweenexposures and back injury.

    Methods This study used data from full-shiftelectromyography (EMG; N¼133) to develop threeexposure metrics: mean, 90th percentile and cumulativeEMG. For each metric, the components of variance werecalculated between- and within-subject, and betweengroupfor four different grouping schemes: grouping byindustry (construction, forestry, transportation,warehousing and wood products), by company, by job andby quintiles based on exposures ranked by jobs withinindustries. Attenuation and precision of simulatedexposureeresponse relationships were calculated for eachgrouping scheme to determine efficient sampling strategies.

    Results As expected, grouping based on exposurequintiles had the highest between-group variances andlowest attenuation, demonstrating the lowest possibleattenuation with this data.

    Conclusion There is potential for grouping schemes toreduce attenuation, but precision losses should beconsidered and whenever possible empirical data shouldbe employed to select potential exposure groupingschemes.

  • 720.
    Trask, Catherine
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research. University of British Columbia School of Environmental Health, Vancouver, BC, Canada.
    Teschke, Kay
    University of British Columbia School of Population and Public Health, Vancouver, Canada .
    Morrison, Jim
    Simon Fraser University School of Kinesiology, Burnaby, Canada.
    Village, Judy
    University of British Columbia School of Environmental Health, Vancouver, Canada.
    Johnson, Peter
    Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, USA.
    Koehoorn, Mieke
    University of British Columbia School of Population and Public Health, Canada .
    Using observation and self-report to predict mean, 90th percentile, and cumulative low back muscle activity in heavy industry workers2010In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 54, no 5, p. 595-606Article in journal (Refereed)
    Abstract [en]

    Occupational injury research depends on the ability to accurately assess workplace exposures for large numbers of workers. This study used mixed modeling to identify observed and self-reported predictors of mean, 90th percentile, and cumulative low back muscle activity to help researchers efficiently assess physical exposures in epidemiological studies. Full-shift low back electromyography (EMG) was measured for 133 worker-days in heavy industry. Additionally, full-shift, 1-min interval work-sampling observations and post-shift interviews assessed exposure to work tasks, trunk postures, and manual materials handling. Data were also collected on demographic and job variables. Regression models using observed variables predicted 31-47% of the variability in the EMG activity measures, while self-reported variables predicted 21-36%. Observation-based models performed better than self-report-based models and may provide an alternative to direct measurement of back injury risk factors.

  • 721.
    Tronarp, Rebecca
    et al.
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Nyberg, André
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Hedlund, Mattias
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Häger, Charlotte K.
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    McDonough, Suzanne
    Institute of Nursing and Health Research, Ulster University, Jordanstown, UK.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Office-cycling: a promising way to raise pain thresholds and increase metabolism with minimal compromising of work performance2018In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, Vol. 2018, article id 5427201Article in journal (Refereed)
    Abstract [en]

    Sedentary behaviour constitutes a risk for lifestyle related diseases and musculoskeletal pain which does not seem to be compensated for by shorter bouts of high intensity physical activity. A way of tackling this may be long term light intensity physical activity while performing office work.

    Aim: Establish the effects of low intensity cycling (LC), moderate intensity cycling (MC) and standing at a simulated office workstation on pain modulation, metabolic expenditure and work performance.

    Methods: 36 healthy adults (21 females), mean age 26.8 (SD 7.6) years, partook in this randomized 3x3 cross-over trial with 75 minutes of LC on 20% of maximum aerobic power output (MAP), 30 minutes of MC on 50% of MAP and standing 30 minutes with 48 hours wash-out periods. Outcome measures were pain modulation (pressure- and thermal pain thresholds, (PPT and TPT)), work performance (transcription, mouse pointing and cognitive performance) and metabolic expenditure.

    Results: PPTs increased in all conditions. Median increase in PPT trapezius was highest after LC; 39.3 kilopascal (kPa) (15.6;78.6) compared to MC; 17.0 kPa (2.8;49.9) and standing; 16.8 kPa (-5.6;39.4), p=0.015. TPT showed no change. Work performance; compared to standing, transcription was reduced during LC and MC, mouse pointing was faster in LC but had more errors while slower with more errors in MC. Performance in the cognitive task did not differ between conditions. Metabolic expenditure rates differed between all conditions (p<0.001) and were 1.4 (1.3;1.7), 3.3 (2.3;3.7) and 7.5 (5.8;8.7) kilocalories per minute during standing, LC and MC, respectively.

    Conclusions: LC seem to be the preferred option since it raised PPTs, more than doubled metabolic expenditure, while minimally influencing work performance when compared to standing. Thus, LC is promising but requires corroboration in field studies.

  • 722.
    van der Beek, Allard
    et al.
    Department of Public and Occupational Health, Amsterdam Public Health research institute, VU University Medical Centre, Amsterdam.
    Dennerlein, Jack T.
    Bouvé College of Health Sciences, Northeastern University, Boston.
    Huysmans, Maaike
    Department of Public and Occupational Health, Amsterdam Public Health research institute, VU University Medical Centre, Amsterdam.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Burdorf, Alex
    Department of Public Health, Erasmus MC, University Medical Center Rotterdam.
    van Mechelen, Willem
    Department of Public and Occupational Health, Amsterdam Public Health research institute, VU University Medical Centre, Amsterdam.
    van Dieën, Jaap
    Department of Human Movement Sciences, Vrije Universiteit Amsterdam.
    Frings-Dresen, Monique
    Academic Medical Center, Department Coronel Institute of Occupational Health and Netherlands Center for Occupational Diseases, Amsterdam.
    Holtermann, Andreas
    National Research Centre for the Working Environment, Copenhagen.
    Janwantanakul, Prawit
    Work-related Musculoskeletal Injury Research Unit, Department of Physical Therapy, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok.
    van der Molen, Henk
    Academic Medical Center, Department Coronel Institute of Occupational Health and Netherlands Center for Occupational Diseases, Amsterdam.
    Rempel, David
    Division of Occupational and Environmental Medicine, University of California, San Francisco.
    Straker, Leon
    Curtin University, School of Physiotherapy and Exercise Science, Perth.
    Walker-Bone, Karen
    Arthritis Research UK/MRC centre for Musculoskeletal Health and Work, University of Southampton.
    Coenen, Pieter
    Department of Public and Occupational Health, Amsterdam Public Health research institute, VU University Medical Centre, Amsterdam.
    A research framework for the development and implementation of interventions preventing work-related musculoskeletal disorders2017In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, E-ISSN 1795-990X, Vol. 43, no 6, p. 526-539Article in journal (Refereed)
    Abstract [en]

    Objectives: Work-related musculoskeletal disorders (MSD) are highly prevalent and put a large burden on the (working) society. Primary prevention of work-related MSD focuses often on physical risk factors (such as on manual lifting and awkward postures), but has not been too successful in reducing the MSD burden. This may partly be caused by insufficient knowledge of etiological mechanisms and/or a lack of adequately feasible interventions (theory failure and program failure, respectively), possibly due to limited integration of research disciplines. A research framework could link research disciplines thereby strengthening the development and implementation of preventive interventions. Our objective was to define and describe such a framework for multi-disciplinary research on work-related MSD prevention.

    Methods: We described a framework for MSD prevention research, partly based on frameworks from other research fields (i.e., sports injury prevention and public health).

    Results: The framework is composed of a repeated sequence of six steps comprising the assessment of 1) incidence and severity of MSD, 2) risk factors for MSD, and 3) underlying mechanisms; and the 4) development, 5) evaluation, and 6) implementation of preventive intervention(s).

    Conclusions: In the present framework for optimal work-related MSD prevention, research disciplines are linked. This framework can thereby help to improve theories and strengthen the development and implementation of prevention strategies for work-related MSD.

  • 723.
    van der Beek, Allard
    et al.
    Department of Public and Occupational Health, VU Medical Center, Amsterdam.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Burdorf, Alex
    Department of Public Health, Erasmus MC, Rotterdam.
    Efficient assessment of exposure to manual lifting using company data2013In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 44, no 3, p. 360-365Article in journal (Refereed)
    Abstract [en]

    The objective of this study, based on an extensive dataset on manual materials handling during scaffolding, was to explore whether routinely collected company data can be used to estimate exposure to manual lifting.The number of manual lifts of scaffold parts while constructing/dismantling scaffolds was well predicted by the number of scaffolders in the team and the type of worksite, in combination with company data of either the number of scaffold parts or the scaffold volume. The proportion of explained variance in the number of lifts ranged from 77% to 92%, depending on the variables in the model. Data on scaffold parts and scaffold volume can easily be obtained from the company’s administration, since this is its usual paperwork supporting logistics and customer invoicing, respectively.We conclude that company data can be a promising source of information for ergonomic practitioners and researchers, to support assessment of manual lifting in scaffolding.

  • 724.
    Veiersted, K B
    et al.
    National Institute of Occupational Health, Oslo, Norway.
    Forsman, Mikael
    Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Comparison of time and level based EMG parameters for assessments of muscle activity patterns2010In: Premus 2010 (Seventh International Conference on Prevention of Work-Related Musculoskeletal Disorders) August 29-September 2, Angers, France, 2010Conference paper (Refereed)
    Abstract [en]

    Sustained trapezius muscle activity has been shown to increase the risk of neck and shoulder pain: number of eight-minute-periods with sustained activity >0.5% EMGmax (Østensvik 2009), and more than 70% of burst time, i.e. working time above 2% EMGmax (Mork 2006). Both studies consider the occurrence of continuous muscle activity above a certain discrimination level. The aim of this study was to evaluate the effect of data processing procedures on similar measures of sustained trapezius muscle activity.

    Full-day bilateral EMG from upper trapezius muscles were collected from forty subjects (17 men, 23 women, median age 22 years, range 22-26), who had just left technical school and started mainly as hairdressers, electricians and students. Number of periods and total duration of activity above discrimination levels 0.5, 1 and 2% EMGmax were retrieved from data processed by each of six Root Mean Square (RMS) window lengths. Several analyses of patterns of activity and rest were made, and this paper presents some basic descriptives concerning total duration of muscle activity.

    The static muscle activity level (APDF) was 0.3% EMGmax and the mean burst time was 65%. The total time of muscle activity depended largely on the discrimination level (Figure: panel A compared to B). For all discrimination levels, the total activity time increased with an increasing RMS length, and became larger when the demands for a minimum period duration were relaxed (figures A and B).

    Thus, muscle activity patterns extracted from EMG are highly sensitive to the data processing procedure and we suggest that a standardized approach should be developed so that future studies will be comparable.

  • 725.
    Veiersted, Kaj Bo
    et al.
    National Institute of Occupational Health, Oslo.
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Hansson, Gert-Åke
    Division of Occupational and Environmental Medicine, Lund University.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Assessment of time patterns of activity and rest in full-shift recordings of trapezius muscle activity - effects of the data processing procedure2013In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 23, no 3, p. 540-547Article in journal (Refereed)
    Abstract [en]

    The purpose of this paper was to compare the effects of different data reduction procedures on the values of variables characterizing the time pattern of trapezius muscle activity during full work shifts. Surface electromyography (EMG) of the right and left upper trapezius muscles were obtained from 40 young subjects in different occupations, mainly electricians, hairdressers and students. The target EMG variables were gap frequency, muscle rest, and the number and duration of episodes with sustained muscle activity (from 0.13 s to 30 min as minimum duration). These variables were derived from the EMG recordings using different Root Mean Square (RMS) windows (from 0.13 to 6.38 s), and discrimination levels between "activity" and "rest" (0.5, 1 and 2 % of maximal EMG). The results give basis for practical suggestions for EMG analyses of full work shifts. For most variables, a discrimination level of 0.5% EMGmax showed to be preferable. The time proportion of muscle rest and sustained muscle activity should, in general, be preferred over the corresponding frequency measures. Sustained muscle activity should be calculated using a RMS window between 1 and 3 s, and preferably be stated in terms of variables describing time proportions of activity. Uninterrupted activity episodes longer than 10 min proved not to be a useful variable due to limited occurrence in many work shifts.

  • 726.
    Veiersted, KB
    et al.
    National Institute of Occupational Health, Oslo, Norway.
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Sulma-periods or bursts: which risk estimating parameters should be used in analyses of long time EMG recordings2010In: The XVIII Congress of the International Society of Electrophysiology and Kinesiology (ISEK), Aalborg, Denmark, 2010Conference paper (Refereed)
    Abstract [en]

    AIM: Sustained trapezius muscle activity has been shown to increase the risk of neck and shoulder pain: number of eight-minute-periods with sustained low-level muscle activity >0.5% EMGmax (SULMA-periods, (1)), and more than 70% of burst time, i.e. working time above 2% EMGmax (2). Both studies consider the occurrence of continuous muscle activity above a certain discrimination level. The aim of this study was to evaluate the effect of data processing procedures on similar measures of sustained trapezius muscle activity.

    METHODS: Full-day bilateral EMG from upper trapezius muscles were collected from forty subjects (17 men, 23 women, median age 22 years, range 22-26), who had just left technical school and started mainly as hairdressers, electricians and students. Number of periods and total duration of activity above discrimination levels 0.5, 1 and 2% EMGmax were retrieved from data processed by each of six Root Mean Square (RMS) window lengths. Several analyses of patterns of activity and rest were made, and this paper presents some basic descriptives concerning total duration of muscle activity.

    RESULTS: The static muscle activity level (APDF) was 0.3% EMGmax and the mean burst time was 65%. The total time of muscle activity depended largely on the discrimination level (Figure: panel A compared to B). For all discrimination levels, the total activity time increased with an increasing RMS length, and became larger when the demands for a minimum period duration were relaxed (figures A and B).

    CONCLUSION: Thus, muscle activity patterns extracted from EMG are highly sensitive to the data processing procedure and we suggest that a standardized approach should be developed so that future studies will be comparable.

  • 727.
    Village, J
    et al.
    School of Environmental Health, College for Interdisciplinary Studies, University of British Columbia.
    Trask, Catherine
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Chow, Y
    School of Environmental Health, College for Interdisciplinary Studies, University of British Columbia.
    Morrison, J B
    School of Biomedical Physiology and Kinesiology, Simon Fraser University.
    Koehoorn, Mieke
    School of Environmental Health, College for Interdisciplinary Studies, University of British Columbia.
    Teschke, Kay
    School of Environmental Health, College for Interdisciplinary Studies, University of British Columbia.
    Assessing whole body vibration exposure for use in epidemiological studies of back injuries: measurements, observations and self-reports2012In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847, Vol. 55, no 4, p. 415-424Article in journal (Refereed)
    Abstract [en]

    Improved assessment of whole body vibration exposure is needed for epidemiological studies investigating the causes of low back disorders. Vibration was measured on 54 worker-days in five heavy industries, with data collected on observed and self-reported driving conditions, demographics, and vehicle characteristics. Variables significant at p<0.1 in simple linear regressions (20 of 34) were retained for mixed effects multiple regressions to determine the best prediction of rms vibration level and 8-h equivalent vibration exposure. Vibration was measured, on average, for 205 min per work shift (SD 105). Means and standard deviations in ms-2 were: x-axis 0.35 (0.19); y-axis 0.34 (0.28); z-axis 0.54 (0.23); vector sum 0.90 (0.49); and 8-h equivalent vector sum 0.70 (0.37). The final three regression models retained only 2 or 3 of the 34 variables (driving speed (<20 km/h and/or 20–40 km/h) and industry and/or vehicle type and explained up to 60% of the variance (R2=0.26–0.6))

  • 728.
    Vingård, Eva
    et al.
    Arbets- och miljömedicin, Uppsala universitet.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Ett nationellt kunskapscentrum för arbetsmiljö: behov och förutsättningar2011Book (Other (popular science, discussion, etc.))
  • 729.
    Wahlström, Jens
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine, Umeå University, Umeå, Sweden.
    Bergsten, Eva
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Trask, Catherine
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Jackson, Jennie
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. IMM Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Full-shift trunk and upper arm postures and movements among aircraft baggage handlers2016In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 60, no 8, p. 977-990Article in journal (Refereed)
    Abstract [en]

    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 (651 hours) were collected with a mean recording time of 495 minutes 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 vs 0.3% sorting; right arm 1.3% ramp vs 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 to sorting workers.

  • 730.
    Wahlström, Jens
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Liv, Per
    University of Gävle, Centre for Musculoskeletal Research.
    Hedlund, Pernilla
    Department of Occupational and Environmental Medicine, Umea University Hospital, SE-901 85 Umeå, Sweden.
    Forsman, Mikael
    Department of Public Health Sciences, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
    Ahlgren, Christina
    Department of Community Medicine and Rehabilitation, Umeå University, SE-901 87 Umeå.
    Mathiassen, Svend Erik
    University of Gävle, Centre for Musculoskeletal Research.
    Direct measurements of upper arm elevation among female hairdressers with special reference to exposure variability2009In: Proceedings of the IEA2009 conference, Beijing, 2009Conference paper (Refereed)
  • 731.
    Wahlström, Jens
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Liv, Per
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Hedlund, Pernilla
    Department of Occupational and Environmental Medicine, Umea University Hospital, SE-901 85 Umeå, Sweden.
    Ahlgren, Christina
    Department of Community Medicine and Rehabilitation, Umea University, SE-901 87 Umeå, Sweden.
    Forsman, Mikael
    Department of Public Health Sciences, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
    Upper arm postures and movements in female hairdressers across four full working days2010In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 54, no 5, p. 584-594Article in journal (Refereed)
    Abstract [en]

    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%) (SD(BS) = 39 min and SD(BD) = 85 min) of the working day and AT and breaks for 207 min (42%) (SD(BS) = 46 min and SD(BD) = 88 min). The hairdressers worked with the right arm elevated >60 degrees for 6.8% of the whole job (SD(BS) = 2.8% and SD(BD) = 2.0%). On average, the hairdressers worked with the right arm elevated >60 degrees 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.

  • 732.
    Waleh Åström, Amanda
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Strömberg, Annika
    University of Gävle, Faculty of Health and Occupational Studies, Department of Social Work and Psychology, Social work.
    Uncertainty in monetary cost estimates for assessing working postures using inclinometry, observation or self-report2017In: NES 2017 ”JOY AT WORK”: Conference Proceedings / [ed] Anna-Lisa Osvalder, Mikael Blomé and Hajnalka Bodnar, 2017, p. 160-161Conference paper (Refereed)
    Abstract [en]

    Background

    In order to optimize cost-efficiency when collecting posture data in field studies, accurate cost data are needed. A few studies have assessed costs of different measurement methods, but they did not address the uncertainty of the cost estimates. Information on the uncertainty of cost estimates is key input when deciding which method to use.

    Aim

    This study aimed atassessingthe uncertainty in estimates of costs for collecting posture data by inclinometry, observations and self-report.

    Method

    The study wasbased on data collected at a Swedish paper mill (Heiden et al. 2017)1. Using a model developed by Trask et al. (2014)2, costs were calculatedfor measuring trunk and upperarm postures of twenty-eight workers during three full shifts using inclinometers, observations from recorded videos, and workers’ self-reports from a questionnaire. For each measurement method, the uncertainty of the actually observed total cost was assessed by determining the range of costs between an assumed best case (lowest cost) and worst case (highest cost) using scenario analysis.

    Results

    Observation was the most expensive method (€41499) and also showed a large uncertainty in the cost estimate (€19089–€87154). Self-reports had the lowest cost (€9156) with the smallest uncertainty (€3941–€27473). The overall cost for inclinometry was €16851 with best and worst cases €8567 and €60313, respectively. The actual costs of inclinometry and self-reports in the conducted study were reasonably close to the best case.

    Discussion

    In their study of flight baggage handling, Trask et al. (2014) concluded that inclinometry was more expensive than observation when measuring trunk and arm postures. In the present study, we found observation to be the more expensive. Given the uncertainty in cost estimates, both results are plausible. Notably, in Trask et al. (2014), video recordings were restricted to 4 hours, whereas in the present material, video recordings covered full 7 -to 12-hour shifts. The time allocated to collecting video material for observations will significantly affect the cost comparison of methods, and this may serve as an example that further investigations of separate cost components for each method are warranted.

    Conclusions

    Based on a meticulous cost assessment, we found that cost estimates for observation of working postures were the most uncertain, followed by inclinometry and self-reports. A better understanding of data collection costs and their uncertainty, and thus of how to properly identifyan optimal measurement method, requires a deeper analysis of the cost model, and of the contributions of separate cost components to the overall cost

    1 https://doi.org/10.1093/annweh/wxw0262

    2 https://doi.org/10.5271/sjweh.3416

  • 733.
    Waleh Åström, Amanda
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Strömberg, Annika
    University of Gävle, Faculty of Health and Occupational Studies, Department of Social Work and Psychology, Social work.
    Uncertainty in monetary cost estimates for assessing working postures using inclinometry, observation or self-report2018In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 71, p. 73-77Article in journal (Refereed)
    Abstract [en]

    Objective: To assess uncertainty in cost estimates for collecting posture data by inclinometry, observations and self-report.

    Method: In a study addressing physical workloads at a paper mill, costs were calculated for measuring postures of twenty-eight workers during three shifts. Uncertainty in costs was assessed for all three methods as the range between an assumed best case (lowest cost) and worst case (highest cost) using scenario analysis.

    Results: The cost for observation was larger, but also more uncertain (€16506 and €89552 in the best and worst case, respectively) than that of inclinometry (€7613 - €45896). Self-report costs were both lower and less uncertain (€3743 - €23368).

    Conclusions: The extent of uncertainty in cost estimates implies that observation could be less expensive than inclinometry, e.g., in a scenario where experienced observers could use existing software, while inclinometers would have to be purchased. We propose adding uncertainty assessments to cost estimates when selecting a method for measuring working postures, and offer guidance in how to proceed in a specific setting.

  • 734.
    Waleh Åström, Amanda
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Heiden, Marina
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Strömberg, Annika
    University of Gävle, Faculty of Health and Occupational Studies, Department of Social Work and Psychology, Social work.
    Uncertainty of cost components in assessments of working posture by different methods2018Conference paper (Refereed)
  • 735.
    Weber, Zachary R.
    et al.
    Department of Kinesiology and Physical Education, McGill University, Montreal, Canada; Occupational Biomechanics and Ergonomics Laboratory, Michael Feil and Ted Oberfeld/CRIR Research Center, Jewish Rehabilitation Hospital, Laval, Quebec, Canada .
    Srinivasan, Divya
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Department of Industrial and Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia.
    Côté, Julie
    Department of Kinesiology and Physical Education, McGill University, Montreal; Occupational Biomechanics and Ergonomics Laboratory, Michael Feil and Ted Oberfeld/CRIR Research Center, Jewish Rehabilitation Hospital, Laval, Quebec, Canada.
    Sex-Specific Links in Motor and Sensory Adaptations to Repetitive Motion-Induced Fatigue2018In: Motor Control, ISSN 1087-1640, E-ISSN 1543-2696, Vol. 22, no 2, p. 149-169Article in journal (Refereed)
    Abstract [en]

    The objectives of this study were to assess the sex-specific relationships between motor and sensory adaptations to repetitive arm motion-induced neck/shoulder fatigue, and measure how additional sensory stimulation affected these adaptations. Twenty-three participants performed two sessions of a repetitive pointing task until scoring 8 on the Borg CR10 scale for neck/shoulder exertion or for a maximum of 45min, with and without sensory stimulation (i.e. light touch) applied on the fatiguing shoulder. Just before reaching the task termination criteria, all participants showed changes in mean and variability of arm joint angles and experienced a five-fold increase in anterior deltoid (AD) sensory threshold in the stimulus-present condition. Women with the greatest increases in AD sensory thresholds demonstrated the greatest increases in shoulder variability (r= .66) whereas men with the greatest increases in upper trapezius sensory thresholds demonstrated greatest changes in shoulder angle (r= -.60) and coordination (r= .65) variability. Thus, sensory stimulation had no influence on time-to-termination but affected how men and women differently adapted, suggesting sex differences in the sensorimotor fatigue response mechanisms.

  • 736.
    Wells, Richard
    et al.
    Kinesiology Department, University of Waterloo, Waterloo, Canada; Institute for Work and Health, Toronto, Canada.
    Mathiassen, Svend Erik
    University of Gävle, Centre for Musculoskeletal Research.
    Medbo, Lars
    Department of Logistics and Transportation, Chalmers University of Technology, Gothenburg, Sweden.
    Winkel, Jörgen
    National Research Centre for Working Environment, Copenhagen, Denmark and Department of Work Science, Gothenburg University, Sweden.
    Time - a key issue for musculoskeletal health and manufacturing2007In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 38, no 6, p. 733-744Article in journal (Refereed)
    Abstract [en]

    Time is a key issue for both ergonomists and engineers when they engage in production system interventions. While not their primary purpose, the actions of engineers have major effects on biomechanical exposure; possibly of much greater magnitude than many ergonomics interventions. This paper summarises the aims, actions and tools of engineers and ergonomists, emphasising time-related outcomes. Activities of the two groups when attempting to manipulate time aspects of work may be contradictory; engineers wishing to improve production and ergonomists aiming at better health as well as contributing to production. Consequently, tools developed by ergonomists for assessing time aspects of work describe rest patterns, movement velocities or daily duration of exposures, while engineering tools emphasise time-efficient production. The paper identifies measures that could be used to communicate time-relevant information between engineers and ergonomists. Further cooperation between these two stakeholders as well as research on the topic are needed to enable ergonomists to have a larger impact on the design of production systems.

  • 737.
    Wersäll, Minke
    et al.
    Swedish Work Environment Authority, Stockholm, Sweden.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Jonsson, Christina
    Swedish Work Environment Authority, Stockholm, Sweden.
    Lorén, Kerstin
    aSwedish Work Environment Authority, Stockholm, Sweden.
    Sjöstedt-Landén, Angelika
    Department of Social Sciences, Mid Sweden University, Östersund, Sweden.
    A Symposium on gender perspectives on musculoskeletal health at work – a Swedish initiative2015In: Proceedings of the 19th Triennial Congress of the International Ergonomics Association, Melbourne 9-14 August 2015, 2015Conference paper (Refereed)
  • 738.
    Wiesinger, Birgitta
    et al.
    Department of Odontology, Clinical Oral Physiology, Umeå University, Umeå, Sweden; Department of Research and Development, Umeå University, Sundsvall, Sweden.
    Häggman-Henrikson, Birgitta
    Department of Odontology, Clinical Oral Physiology, Umeå University, Umeå, Sweden; Department of Orofacial Pain and Jaw Function, Malmö University, Malmö, Sweden.
    Hellström, Fredrik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Englund, Erling
    Department of Research and Development, Umeå University, Sundsvall, Sweden.
    Wänman, Anders
    Department of Odontology, Clinical Oral Physiology, Umeå University, Umeå, Sweden.
    Does induced masseter muscle pain affect integrated jaw-neck movements similarly in men and women?2016In: European Journal of Oral Sciences, ISSN 0909-8836, E-ISSN 1600-0722, Vol. 124, no 6, p. 546-553Article in journal (Refereed)
    Abstract [en]

    Normal jaw opening-closing involves simultaneous jaw and head-neck movements. We previously showed that, in men, integrated jaw-neck movements during jaw function are altered by induced masseter muscle pain. The aim of this study was to investigate possible sex-related differences in integrated jaw-neck movements following experimental masseter muscle pain. We evaluated head-neck and jaw movements in 22 healthy women and 16 healthy men in a jaw opening-closing task. The participants performed one control trial and one trial with masseter muscle pain induced by injection of hypertonic saline. Jaw and head movements were registered using a three-dimensional optoelectronic recording system. There were no significant sex-related differences in jaw and head movement amplitudes. Head movement amplitudes were significantly greater in the pain trials for both men and women. The proportional involvement of the neck motor system during jaw movements increased in pain trials for 13 of 16 men and for 18 of 22 women. Thus, acute pain may alter integrated jaw-neck movements, although, given the similarities between men and women, this interaction between acute pain and motor behaviour does not explain sex differences in musculoskeletal pain in the jaw and neck regions.

  • 739.
    Wiesinger, Birgitta
    et al.
    Dept. of Odontology, Clinical Oral Physiology, Umeå University.
    Häggman-Henrikson, Birgitta
    Dept. of Odontology, Clinical Oral Physiology, Umeå University.
    Hellström, Fredrik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Wänman, Anders
    Dept. of Odontology, Clinical Oral Physiology, Umeå University.
    Experimental masseter muscle pain alters jaw-neck motor strategy2013In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 17, no 7, p. 995-1004Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    A functional integration between the jaw and neck regions has been demonstrated during normal jaw function. The effect of masseter muscle pain on this integrated motor behaviour in man is unknown. The aim of this study was to investigate the effect of induced masseter muscle pain on jaw-neck movements during a continuous jaw opening-closing task.

    METHODS:

    Sixteen healthy men performed continuous jaw opening-closing movements to a target position, defined as 75% of the maximum jaw opening. Each subject performed two trials without pain (controls) and two trials with masseter muscle pain, induced with hypertonic saline as a single injection. Simultaneous movements of the mandible and the head were registered with a wireless optoelectronic three-dimensional recording system. Differences in movement amplitudes between trials were analysed with Friedman's test and corrected Wilcoxon matched pairs test.

    RESULTS:

    The head movement amplitudes were significantly larger during masseter muscle pain trials compared with control. Jaw movement amplitudes did not differ significantly between any of the trials after corrected Wilcoxon tests. The ratio between head and jaw movement amplitudes was significantly larger during the first pain trial compared with control.

    CONCLUSIONS:

    Experimental masseter muscle pain in humans affected integrated jaw-neck movements by increasing the neck component during continuous jaw opening-closing tasks. The findings indicate that pain can alter the strategy for jaw-neck motor control, which further underlines the functional integration between the jaw and neck regions. This altered strategy may have consequences for development of musculoskeletal pain in the jaw and neck regions.

  • 740.
    Wiesinger, Birgitta
    et al.
    Umeå University and Västernorrland County Council.
    Häggman-Henriksson, Birgitta
    Umeå University and Malmö University.
    Wänman, Anders
    Umeå University.
    Lindqvist, Mikael
    Umeå University.
    Hellström, Fredrik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Jaw-opening accuracy is not affected by masseter muscle vibration in healthy men2014In: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 232, no 11, p. 3501-3508Article in journal (Refereed)
    Abstract [en]

    There is a functional integration between the jaw and neck regions with head extension–flexion movements during jaw-opening/closing tasks. We recently reported that trigeminal nociceptive input by injection of hypertonic saline into the masseter muscle altered this integrated jaw–neck function during jaw-opening/closing tasks. Thus, in jaw-opening to a predefined position, the head–neck component increased during pain. Previous studies have indicated that muscle spindle stimulation by vibration of the masseter muscle may influence jaw movement amplitudes, but the possible effect on the integrated jaw–neck function is unknown. The aim of this study was to investigate the effect of masseter muscle vibration on jaw–head movements during a continuous jaw-opening/closing task to a target position. Sixteen healthy men performed two trials without vibration (Control) and two trials with bilateral masseter muscle vibration (Vibration). Movements of the mandible and the head were registered with a wireless three-dimensional optoelectronic recording system. Differences in jaw-opening and head movement amplitudes between Control and Vibration, as well as achievement of the predefined jaw-opening target position, were analysed with Wilcoxon’s matched pairs test. No significant group effects from vibration were found for jaw or head movement amplitudes, or in the achievement of the target jaw-opening position. A covariation between the jaw and head movement amplitudes was observed. The results imply a high stability for the jaw motor system in a target jaw-opening task and that this task was achieved with the head–neck and jaw working as an integrated system.

  • 741. Wiholm, C
    et al.
    Richter, Hans O
    University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend-Erik
    University of Gävle, Centre for Musculoskeletal Research.
    Toomingas, A
    Associations between eyestrain and neck-shoulder symptoms among call centre operators2007In: Work With Display Unit, 2007Conference paper (Other (popular science, discussion, etc.))
  • 742. Wiholm, Clairy
    et al.
    Richter, Hans O.
    University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend Erik
    University of Gävle, Centre for Musculoskeletal Research.
    Toomingas, Allan
    Associations between eyestrain and neck-shoulder symptoms among call centre operators2007In: Scandinavian Journal of Work, Environment & Health, ISSN 0356-6528, no Suppl. 3, p. 54-59Article in journal (Refereed)
    Abstract [en]

    Few if any studies have investigated if eyestrain and shoulder-neck symptoms are correlated, although functional links could be expected on the basis of neurophysiological evidence. The present cross sectional study assessed correlations between self-reported eye strain and shoulder-neck symptoms among call centre workers, controlling for possible confounders for these ailments. A questionnaire concerning socioeconomic background, work conditions and symptoms was mailed to 1531 employees at 28 different call centers during the years 2001- 2003. Twenty-one percent of responding subjects (N = 1162) reported both eyestrain and neck shoulder symptoms, 46% reported neck/shoulder and 6 % eye symptoms. 46% were free from symptoms in these regions. A significant positive association was found between eyestrain and neck/shoulder symptoms. Significant covariates for shoulder-neck disorders were eyestrain (OR = 1.6 p = 0.007), gender (to be female) (OR 1.9, p < 0.001, irritation index (OR 1.2, p =0.03), and feeling stressed (OR 1.2, p = 0.001. In a multi-nominal regression analysis gender (female) (OR = 1.9, p = 0.002), feeling stressed (OR 1.3, p = 0.002), feelings of distress (OR = 1.7, p < 0.001), computer problems (OR 1.3, p = 0.002)) and social support (OR 0.6, p = 0.003) remained in the model for the eye/neck symptoms. The results from this study support an association between self-reported combined eyestrain and shoulder-neck symptoms. However no causal relations can be derived due to the cross-sectional design.

  • 743. Wiholm, Clairy
    et al.
    Richter, Hans O
    University of Gävle, Centre for Musculoskeletal Research.
    Mathiassen, Svend-Erik
    University of Gävle, Centre for Musculoskeletal Research.
    Toomingas, Allan
    Samband mellan ögon och nacke/skulder besvär bland professionella datoranvändare2007In: Svenska Läkaresällskapets Riksstämma, 2007Conference paper (Other academic)
  • 744.
    Wiitavaara, Birgitta
    University of Gävle, Centre for Musculoskeletal Research.
    Balancing intrusive illness: the experiences of people with musculoskeletal problems2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The overall aim of the present thesis was to explore and describe the health experiences of men and women with musculoskeletal problems. The specific aims of the four papers were: (I) to explore the experience of illness and wellness among ambulance personnel with musculoskeletal symptoms; (II) to explore the experience of illness and wellness among female health care personnel with musculoskeletal symptoms; (III) to explore the experience of bodily illness among people with musculoskeletal problems in the neck-shoulder region, and; (IV) to investigate the symptoms described by people with non-specific neck-shoulder problems, to investigate the method of development of neck-shoulder questionnaires that assesses pain and other symptoms, to analyse the content and items of these questionnaires, and to compare the findings.

    The overall findings show that the occupationally active men and women with MSDs were “striving for balance” (I-II), that the disease course of chronic neck-shoulder disorders was characterised by “uncontrollable fluctuations” (III), and that most neck-shoulder questionnaires had a low correspondence to the variety of symptoms experienced during this course (IV). In the process of striving for balance (I-II), the informants’ health experiences were not a state of either wellness or illness, but of both, in varying degrees at different times. The balancing started when illness became too intrusive, and was a process of minimising the impact of illness by accepting and handling it, while attaining and maintaining wellness to feel well enough. When striving for balance, the interviewees kept on working to continue being nurtured at the same time as they made different efforts directed at minimising the impact of their illness. For both men and women, illness was characterised by disembodiment, vulnerability, and exhaustion. The illness experiences were counterbalanced by wellness, where some differences could be recognised between the men and the women. Study III further explored the experiences of bodily illness, focusing on people with chronic musculoskeletal disorders in the neck-shoulder region. The course of the disorder was described as characterised by uncontrollable fluctuations, and it usually developed from insidious symptoms to a state of constant discomfort. The participants experienced calmer periods during the course, but intermittent events of increasing illness were always lying in wait, with periodic moments of consuming intensity. In the interviews included in study IV a variety of symptoms were expressed, which indicated a bodily, mental, and emotional engagement, which included more general and more severe symptoms than are usually related to neck-shoulder disorders. Few of the questionnaires were developed using the experiences of the affected. Taken as a whole, did the questionnaires cover many of the symptoms of the interviewees, but each individual questionnaire only included a few. The fluctuations and nuances of symptoms were rarely considered. The correspondence between individual questionnaires and the experiences of those affected was most often low. This thesis reveals other aspects of health than just bodily experiences as important among occupationally active people with MSDs. It also provides a description of the disease course, and an indication of possibilities for improvement of neck-shoulder questionnaires

  • 745.
    Wiitavaara, Birgitta
    University of Gävle, Centre for Musculoskeletal Research.
    Health as balance: illness and wellness among persons with musculoskeletal disorders2006In: 5th Global Conference Making Sense Of: Health, Illness and Disease, 2006Conference paper (Refereed)
    Abstract [en]

    Musculoskeletal disorders is a condition mostly approached from an out-side perspective and with quantitative methodology. This paper presents health experiences of men with musculoskeletal problems, explored through narrative interviews and constant comparative analysis. As there is a need for further research concerning people with early musculoskeletal symptoms, we turned to persons still active in working life. Ten men working as ambulance personnel were interviewed about their health experiences.

    The analysis revealed a process of striving for balance between experiences of illness and wellness. The informants’ health experiences were not a state of either wellness or illness but both, in varying degrees at different times. The process of striving for balance started when the illness experience became too intrusive, and was a process of both minimising the impact of illness by accepting and handling it and attaining and maintaining enough wellness to strike a balance. The state of balance was the experience of feeling “well enough”.

    Illness was characterised by disembodiment, vulnerability, and exhaustion, as the illness experiences incorporated feelings of that the previously silent body made it self heard, of being vulnerable when suffering gets too close and of getting worn out. Those experiences were counterbalanced by wellness, which was nurtured by experiences of relatedness, usefulness, being some one, and by excitement, challenge, and freedom.

  • 746.
    Wiitavaara, Birgitta
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Well but ill: Lay perspectives on health among people with musculoskeletal disorders.2012Conference paper (Refereed)
    Abstract [en]

    This study departs from questions arisen in previous interview studies of health experiences with people with musculoskeletal disorders. During data collection about health experiences in this group a common comment to the question –“How do you experience your health”? was –“Well, but”…  This awoke our interest to further explore this topic. Thus the aim of present study was to investigate lay perspectives on health among people with musculoskeletal disorders. Semi-structured interviews were performed with 68 women and men with long term (>3 months) musculoskeletal disorders in neck, shoulder and/or low back. All informants were recruited as participants in previous studies on health experiences among people with MSDs (Wiitavaara et al., 2007a, b, 2008, 2009). The informants (39 women and 29 men), were 18-64 years old and most of them were occupationally active in a variety of different occupations. Analysis was performed using qualitative content analysis (Graneheim & Lundman, 2003). The lay perspective on health in this group of people with musculoskeletal problems was perceived as “Having resources and possibilities to lead the life one want”. This theme incorporated three main categories as the informants perceived health to include “A good enough physical and psychological functioning and balance”; “Freedom of action”; and “A positive state of emotion and an enriching social life”. The informants expressed a holistic view of health, encompassing physical, psychological, emotional, as well as social aspects, which can be interpreted from an action theoretical perspective (Nordenfelt, 2007).

  • 747.
    Wiitavaara, Birgitta
    et al.
    University of Gävle, Centre for Musculoskeletal Research. Department of Nursing, Umeå University, Umeå, Sweden.
    Barnekow-Bergkvist, Margareta
    University of Gävle, Centre for Musculoskeletal Research.
    Brulin, Christine
    Department of Nursing, Umeå University, Umeå, Sweden.
    Striving for balance: a grounded theory study of health experiences of nurses with musculoskeletal problems.2007In: International Journal of Nursing Studies, ISSN 0020-7489, E-ISSN 1873-491X, Vol. 44, no 8, p. 1379-1390Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Musculoskeletal disorders (MSD) are one of the major causes of the high levels of long-term sickleave and early retirement, and healthcare personnel are among the occupational groups most affected. Only limited research in the area has focused on the experiences of those affected, and to increase the understanding of MSD, all dimensions of the health experiences need to be taken into consideration. OBJECTIVES: The aim of this paper was to explore the experiences of illness and wellness among female healthcare personnel with musculoskeletal symptoms. DESIGN: A qualitative grounded theory approach guided the study in data collection and analysis. SETTINGS: Medical and surgical ward units at three hospitals; one university hospital and two minor hospitals. PARTICIPANTS: Eight women, registered nurses and nursing aides, with neck, shoulder and/or back problems in early stages. METHODS: A grounded theory approach was used with narrative thematic interviews and parallel data analysis with constant comparisons. RESULTS: The analysis revealed a process of striving to reach a balance between illness and wellness, through accepting and handling illness. Illness appeared as a threat and an experience, while experiences of wellness were simultaneously nurtured. The informants were striving for balance through an inner reasoning leading to acceptance and by handling illness in various ways depending on the character of the illness. CONCLUSION: This paper indicates the diversity of the illness experience, the parallel importance of wellness, and the process of balancing these two in order to feel well enough. As previous research has shown that MSD has a multifactorial cause, a holistic view of health promotion, prevention and rehabilitation may provide a more effective tool than the bodily physical focus most frequently used today.

  • 748.
    Wiitavaara, Birgitta
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Bengs, Carita
    Sociologiska institutionen, Umeå universitet.
    Brulin, Christine
    Institutionen för omvårdnad, Umeå universitet.
    Lekmannaperspektiv på hälsa bland personer med muskuloskeletala besvär2015In: Best Practice : Smärta, Vol. 4, no 10, p. 20-23Article in journal (Other academic)
  • 749.
    Wiitavaara, Birgitta
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Bengs, Carita
    Sociologiska institutionen, Umeå universitet.
    Brulin, Christine
    Institutionen för omvårdnad, Umeå universitet.
    Well, I'm healthy, but...: lay perspectives on health among people with musculoskeletal disorders2016In: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, Vol. 38, no 1, p. 71-80Article in journal (Refereed)
    Abstract [en]

    urpose: The purpose was to investigate lay perspectives on health among people with musculoskeletal disorders. Method: Semi-structured interviews were performed with 39 women and 30 men, (aged 22–63 years) with long-term, non-specific musculoskeletal disorders in the neck, shoulder and/or low back. Data was analysed using qualitative content analysis. Results: These people experienced health as “having resources and opportunities to lead the life one wants”. Three categories, “a good enough physical and psychological functioning, freedom of action, and a positive state of emotion and an enriching life”, illustrate the different resources and opportunities that the informants described as important for them to perceive themselves as healthy. The informants also reflected on “being ill” and “being well” and what makes the difference. Five aspects influenced the dynamics of their health experiences: “body and soul, prognosis, character of symptoms, physical and social activity, and emotional state”. Consequently, the informants expressed a holistic view of health, where the focus lies on the opportunity and the ability to lead their lives the way they want. Conclusions: This study points at the value of taking lay perspectives on health into account, as it might increase the opportunity to design effective, personalized rehabilitation strategies.

  • 750.
    Wiitavaara, Birgitta
    et al.
    University of Gävle, Centre for Musculoskeletal Research. Department of Nursing, Ume̊ University, Umeå, Sweden.
    Björklund, Martin
    University of Gävle, Centre for Musculoskeletal Research. Alfta Research Foundation, Alfta, Sweden.
    Brulin, Christine
    Department of Nursing, Ume̊ University, Umeå, Sweden.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    How well do questionnaires on symptoms in neck-shoulder disorders capture the experiences of those who suffer from the disorders?: A content analysis of questionnaires and interviews2009In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 10, no 1, article id 30Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Previous research has indicated neck-shoulder disorders to have a fluctuating course incorporating a variety of symptoms. These findings awoke our interest to make a comparison between symptoms experienced by people affected with the disorder and the content of questionnaires that assess pain and other symptoms in neck-shoulder disorders. Thus the aims of this study were: -to explore the symptoms experienced by people with non-specific neck-shoulder problems, as well as experiences of nuances and temporal variations (fluctuations) of symptoms; -to investigate which sources were used in the development of ten questionnaires for assessing pain and other symptoms in the neck-shoulder; -to analyse the item content of the questionnaires; -to analyse the correspondence between the item content of the questionnaires and the symptoms described by the informants. METHODS: Content analysis of interviews with 40 people with non-specific neck-shoulder pain, and 10 questionnaires used to assess pain and other symptoms in neck-shoulder disorders. RESULTS: The interviews revealed a variety of symptoms indicating a bodily, mental/cognitive, and emotional engagement, and more general and severe symptoms than are usually considered in neck-shoulder questionnaires. Taking all questionnaires together many of the symptoms were considered, but most questionnaires only included a few of them. The informants were able to distinguish fluctuation of symptoms, and a variety of different qualities which were not usually considered in the questionnaires. Only two questionnaires had made use of the opinions of affected people in the development. CONCLUSIONS: Few of the questionnaires had made use of the experiences of affected people in the development. The correspondence between the symptoms expressed by the affected and the content of the questionnaires was low. A variety of symptoms were expressed by the interviewees, and the participants were also able to distinguish nuances and fluctuations of symptoms. The present study points to the importance of other aspects than just pain and physical functioning as clinical trial outcome measures related to neck-shoulder disorders. To develop a condition-specific questionnaire, it is important to decide on the specific symptoms for the condition. Using the experiences of those affected, in combination with relevant research and professional knowledge, can enhance the validity of the questionnaires.

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