| 61. |
- Ciccarelli, M, et al.
(författare)
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ITKids : does computer use reduce postural variability in children?
- 2006
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Ingår i: Meeting diversity in ergonomics.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Many schoolchildren frequently use computers. Lack of postural variation is proposed as a risk factor for musculoskeletal disorders (MSDs) in adult computer users, but the effect of computer use on children's postural t variation is unknown. This study exarnined if there was a reduction in postural variability among schoolchildren when ! using computers compared to other tasks. Nine schoolchildren were observed in their natural environment while upper body postures were measured using inclinometers. Tasks performed and type of technology used was documented by an observer and matched to postural data with a rninute-to-rninute resolution. A comparison was made of postures during New Information and Communication Technology (ICT) tasks ( electronic-based), Old ICT (paperbased), and Non ICT tasks. Mean postures were deterrnined and postural variation was characterised using an index based on the Exposure Variation Analysis (EV A) matrix, and the range between the 10th and 90th percentiles of the Amplitude Probability Distribution Function (APDF). New ICT produced more neutral postures but significantly lower postural variation. Old ICT had less neutral postures but greater postural variation. The relationship between lack of variation and MSDs among children requires further investigation.
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| 62. |
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| 63. |
- Ciccarelli, Marina, et al.
(författare)
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ITKids Part I : Children's occupations and use of information and communication technologies
- 2011
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Ingår i: Work. - 1051-9815 .- 1875-9270. ; 38:4, s. 401-412
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Tidskriftsartikel (refereegranskat)abstract
- Background: Reports in the popular media are that school children use modern information and communication technology (ICT) on a regular basis for a variety of purposes, however little has been documented in the scientific literature about how school children spend their time and the different types of ICT they use.Method: This paper describes the observed occupations and ICT use of nine Australian primary school children in their natural environments at school and away-from-school during one school day, and compares self-reported exposures with direct observations. Self-reported discomfort scores were obtained throughout the day.Results: The study identified that paper-based ICT (Old ICT) was used mostly for productive occupations at school, while electronics-based (New ICT) was used mostly during leisure in away-from-school locations. Tasks involving no ICT (Non ICT) accounted for the largest proportion of time in both locations during self-care, leisure and instrumental occupations. End-of-day self-reported time performing different occupations was consistent with data from independent observations. Self reported time using Old ICT and New ICT was marginally over-estimated, and time spent using Non-ICT was marginally under-estimated.Conclusion: The children in this study used a variety of ICT in the performance of daily occupations in their natural environments. New ICT use was primarily for leisure, but time spent was less than reported among other child studies. Discomfort reports among the participants were low. Children’s self-reports of daily occupations and ICT use has utility as an exposure assessment metric.
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| 64. |
- Ciccarelli, Marina, et al.
(författare)
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ITKids Part II : Variation of postures and muscle activity in children using different information and communication technologies
- 2011
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Ingår i: Work. - 1051-9815 .- 1875-9270. ; 38:4, s. 413-427
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Tidskriftsartikel (refereegranskat)abstract
- Background: There are concerns that insufficient variation in postural and muscle activity associated with modern information and communication technology (ICT) tasks presents a risk for musculoskeletal ill-health among school children. However, scientific knowledge on physical exposure variation in this group is limited.Method: Postures of the head, upper back and upper arm, and muscle activity of the right and left upper trapezius and right forearm extensors were measured over 10-12 hours in nine school children using different types of ICT at school and away-from-school. Variation in postures and muscle activity was quantified using two indices, EVAsd and APDF(90-10).Results: Paper-based (Old) ICT tasks produced postures that were less neutral but more variable than electronics-based (New ICT) and Non-ICT tasks. Non-ICT tasks involved mean postures similar to New ICT tasks, but with greater variation. Variation of muscle activity was similar between ICT types in the right and left upper trapezius muscles. Non-ICT tasks produced more muscle activity variation in the right forearm extensor group compared to New and Old ICT tasks.Conclusion: Different ICT tasks produce different degrees of variation of postures and muscle activity. Combining tasks that use different ICT may increase overall exposure variation. More research is needed to determine what degree of postural and muscle activity variation is associated with reduced risk of musculoskeletal ill-health.
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| 65. |
- Ciccarelli, Marina, et al.
(författare)
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Posture variation among office workers when using different information and communication technologies at work and away from work
- 2014
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 57:11, s. 1678-1686
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Tidskriftsartikel (refereegranskat)abstract
- Office workers perform tasks using different information and communication technologies (ICT) involving various postures. Adequate variation in postures and muscle activity is generally believed to protect against musculoskeletal complaints, but insufficient information exists regarding the effect on postural variation of using different ICT. Thus, this study among office workers aimed to determine and compare postures and postural variation associated with using distinct types of ICT. Upper arm, head and trunk postures of 24 office workers were measured with the Physiometer® over a whole day in their natural work and away-from-work environments. Postural variation was quantified using two indices; APDF(90-10) and EVA(sd).Various ICT had different postural means and variation. Paper-based tasks had more non-neutral, yet also more variable postures. Electronics-based tasks had more neutral postures, with less postural variability. Tasks simultaneously using paper- and electronics-based ICT had least neutral and least variable postures. Tasks without ICT usually had the most posture variability. Interspersing tasks involving different ICT could increase overall exposure variation among office workers and may thus contribute to musculoskeletal risk reduction.
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| 66. |
- Ciccarelli, Marina, et al.
(författare)
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Variation in Muscle Activity Among Office Workers When Using Different Information Technologies at Work and Away From Work
- 2013
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Ingår i: Human Factors. - : SAGE Publications. - 0018-7208 .- 1547-8181. ; 55:5, s. 911-923
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To determine differences in muscle activity amplitudes and variation of amplitudes, when using different Information and Communication Technologies (ICT).Background: Office workers use different ICT to perform tasks. Upper body musculoskeletal complaints are frequently reported by this occupational group. Increased muscle activity and insufficient muscle activity variation are potential risk factors for musculoskeletal complaints.Method: Muscle activity of right and left upper trapezius and right wrist extensor muscle bundle (extensor carpi radialis longus and brevis) of 24 office workers (performing their usual tasks requiring different ICT at work and away-from-work) were measured continuously over 10-12 hours. Muscle activity variation was quantified using two indices, APDF(90-10) and EVAsd.Results: There was a trend for electronics-based New ICT tasks to involve less electromyography (EMG) variation than paper-based Old ICT tasks. Performing Combined ICT tasks (i.e. using paper- and electronics-based ICT simultaneously) resulted in the highest muscle activity levels and least variation; however, these Combined ICT tasks were rarely performed. Tasks involving no ICT (Non-ICT) had the greatest muscle activity variation.Conclusion: Office workers in this study used various ICT during tasks at work and away-from-work. The high EMG amplitudes and low variation observed when using Combined ICT may present the greatest risk for musculoskeletal complaints, and use of Combined ICT by workers should be kept low in office work. Breaking up Combined, New and Old ICT tasks; for example, by interspersing highly variable Non-ICT tasks into office workers’ daily tasks, could increase overall muscle activity variation and reduce risk for musculoskeletal complaints.
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| 67. |
- Coenen, Pieter, et al.
(författare)
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Bias and power in group-based epidemiologic studies of low-back pain exposure and outcome : effects of study size and exposure measurement efforts
- 2015
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 59:4, s. 439-454
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Exposure-outcome studies, for instance on work-related low-back pain (LBP), often classify workers into groups for which exposures are estimated from measurements on a sample of workers within or outside the specific study. The present study investigated the influence on bias and power in exposure-outcome associations of the sizes of the total study population and the sample used to estimate exposures.Methods: At baseline, lifting, trunk flexion, and trunk rotation were observed for 371 of 1131 workers allocated to 19 a-priori defined occupational groups. LBP (dichotomous) was reported by all workers during three years of follow-up. All three exposures were associated with LBP in this parent study (p<0.01).All 21 combinations of n=10,20,30 workers per group with an outcome, and k=1,2,3,5,10,15,20 workers actually being observed were investigated using bootstrapping, repeating each combination 10,000 times. Odds ratios (OR) with p-values were determined for each of these virtual studies. Average OR and statistical power (p<0.05 and p<0.01) was determined from the bootstrap distributions at each (n,k) combination.Results: For lifting and flexed trunk, studies including n≥20 workers, with k≥5 observed, led to an almost unbiased OR and a power >0.80 (p-level 0.05). A similar performance required n≥30 workers for rotated trunk. Small numbers of observed workers (k) resulted in biased OR, while power was, in general, more sensitive to the total number of workers (n).Conclusions: In epidemiologic studies using a group-based exposure assessment strategy, statistical performance may be sufficient if outcome is obtained from a reasonably large number of workers, even if exposure is estimated from only few workers per group.
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| 68. |
- Coenen, Pieter, et al.
(författare)
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Calibration of self-reported physical behaviours among office workers: A compositional data analysis
- 2019
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Ingår i: ICAMPAM 2019. - Maastricht : ICAMPAM.
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Konferensbidrag (refereegranskat)abstract
- The aim of this study was to develop and evaluate calibration models to predict objectively measured time spent sitting, standing and walking during office work from self-reported time-use compositions using a compositional data analysis (CoDA) approach. Ninety-nine office workers (49 women) at the Swedish Transport Administration participated in an intervention study on relocation to activity-based offices. At baseline and at a 3-months follow-up, physical behaviours (sitting, standing and walking) at work were assessed for five days using a thigh-mounted accelerometer (Actigraph) and by self-report (IPAQ). The time-use composition of the three behaviours was expressed in terms of isometric log-ratios (ILR). Calibration models predicting accelerometry-based time-use from self-reported compositions were constructed using linear regression on baseline data, and then validated using follow-up data. The accelerometer data showed that, on average, workers spent 69.9% of their day sitting, 23.7% standing, and 6.4% walking. The corresponding percentages for self-reports were 71.7%, 21.6%, and 7.4%, respectively. Non-calibrated self-reports were biased: the RMS errors obtained from the ILRs expressing sitting, standing and walking were 0.73, 1.09 and 1.05, respectively. Calibration models reduced these errors by 45% (sitting), 56% (standing), and 76% (walking). Validation of the calibration models using follow-up data from the same workers showed calibration remained equally effective; RMS errors were reduced by 55% (sitting), 58% (standing), and 75% (walking). In conclusion, calibration models for compositional time-use data were effective in reducing bias in self-reported physical behaviours at work, and the models remained effective when used on new data from the same workers. Calibrated self-reports may represent a cost-effective method for obtaining physical behaviour data with a satisfying accuracy in large-scale cohort and intervention studies.
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| 69. |
- Coenen, Pieter, et al.
(författare)
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Correction of bias in self-reported sitting time among office workers – a study based on compositional data analysis
- 2020
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 46:1, s. 32-42
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Emerging evidence suggests that excessive sitting has negative health effects. However, this evidence largely relies on research using self-reported sitting time, which is known to be biased. To correct this bias, we aimed at developing a calibration model estimating "true" sitting from self-reported sitting.Methods: Occupational sitting time was estimated by self-reports (the International Physical Activity Questionnaire) and objective measurements (thigh-worn accelerometer) among 99 Swedish office workers at a governmental agency, at baseline and 3 and 12 months afterwards. Following compositional data analysis procedures, both sitting estimates were transformed into isometric log-ratios (ILR). This effectively addresses that times spent in various activities are inherently dependent and can be presented as values of only 0−100%. Linear regression was used to develop a simple calibration model estimating objectively measured "true" sitting ILR (dependent variable) from self-reported sitting ILR (independent variable). Additional self-reported variables were then added to construct a full calibration model. Performance of the models was assessed by root-mean-square (RMS) differences between estimated and objectively measured values. Models developed on baseline data were validated using the follow-up datasets.Results: Uncalibrated self-reported sitting ILR showed an RMS error of 0.767. Simple and full calibration models (incorporating body mass index, office type, and gender) reduced this error to 0.422 (55%) and 0.398 (52%), respectively. In the validations, model performance decreased to 57%/62% (simple models) and 57%/62% (full models) for the two follow-up data sets, respectively.Conclusions: Calibration adjusting for errors in self-reported sitting led to substantially more correct estimates of "true" sitting than uncalibrated self-reports. Validation indicated that model performance would change somewhat in new datasets and that full models perform no better than simple models, but calibration remained effective.
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| 70. |
- Coenen, Pieter, et al.
(författare)
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Group-based exposuremeasurement strategies and their effects on trunk rotation and low-back pain exposure-outcome associations
- 2013
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Ingår i: Occupational & Environmental Medicine. - : BMJ Journals. ; , s. A101-A102
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Konferensbidrag (refereegranskat)abstract
- Objectives In epidemiological studies of occupational exposures (e.g. lifting) and low-back pain (LBP), group-based exposure measurement strategies are common. Workers are classified into exposure groups; exposure is measured only in a selection of workers in each group, and their mean exposure is assigned to all workers in the group. Exposure-outcome relationships are then determined by regression, relating exposure estimates with individual LBP data from all subjects. The objective of this study was to assess the effect of different group-based measurement strategies on exposure-outcome associations.Methods 1122 workers, classified into 19 groups on the basis of job-related exposure, participated in this study. In each group, videos were collected from ~25% of the workers (in total, 370 workers), and percentage of the work day spent in trunk rotation was estimated by observation of the videos. This estimate of trunk rotation was significantly associated with self-reported LBP during three years of follow-up (OR:1.43 (1.06–1.93)).Using a bootstrap simulation, workers per group (n = 10, 20, 30, 40) and percentage of observed workers (k = 10, 20, 30, 40, 50%) were varied. For each combination, (nk) workers were selected with replacement in each job group among those observed, and n (100-k) workers among those not observed. The mean exposure of the observed workers was assigned to all group members which was related to individual LBP data. ORs and accompanying p-level was estimated using logistic-regression.Results A group-based measurement protocol led to significant (p < 0.05) ORs when the total number of workers was larger than n = 30 in each job group, and ≥20% was actually observed.Conclusions The proportion of observed workers did have an effect on p-values, but it appeared weaker than that of changing the total group size. These results suggest that it may be sufficient to observe only a minor proportion of workers if the overall size of the population is reasonably large.
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