Task exposures in an office environment: a comparison of methods

Effects of a Dynamic Chair on Chair Seat Motion and Trunk Muscle Activity during Office Tasks and Task Transitions

Employing dynamic office chairs might increase the physical (micro-) activity during prolonged office sitting. We investigated whether a dynamic BioSwing^® chair increases chair sway and alters trunk muscle activation. Twenty-six healthy young adults performed four office tasks (reading, calling, typing, hand writing) and transitions between these tasks while sitting on a dynamic and on a static office chair. For all task-transitions, chair sway was higher in the dynamic condition (p < 0.05). Muscle activation changes were small with lower mean activity of the left obliquus internus during hand writing (p = 0.07), lower mean activity of the right erector spinae during the task-transition calling to hand writing (p = 0.036), and higher mean activity of the left erector spinae during the task-transition reading to calling (p = 0.07) on the dynamic chair. These results indicate that an increased BioSwing^® chair sway only selectively alters trunk muscle activation. Adjustments of chair properties (i.e., swinging elements, foot positioning) are recommended.

Correctness of Self-Reported Task Durations: A Systematic Review

Objectives

Duration of tasks in a job is an essential interest in occupational epidemiology. Such duration is frequently measured using self-reports, which may, however, be associated with both bias and random errors. The present systematic literature review examines the correctness of self-reported durations of tasks, i.e. the extent to which they differ from more valid reference data due to either systematic or random errors, and factors influencing this correctness, with particular emphasis on the assessment of exposures of relevance to musculoskeletal disorders.

Methods

The search for relevant studies included the databases ISI Web of Science, MEDLINE, EBSCO HOST, Proquest, and Psycnet.

Results

Thirty-two articles were identified; of which, 23 examined occupational tasks and 9 examined non-occupational tasks. Agreement between self-reports and a more correct reference was reported for, in total, 182 tasks. Average proportional errors were, for most tasks, between -50% (i.e. underestimations) and +100%, with a dominance of overestimations; 22% of all results considered overestimations of 100% or more. For 15% of the 182 reported tasks, the mean difference between the self-reported and the reference duration value was <5%, and 20% of the 182 mean differences were between 5 and 20%. In general, respondents were able to correctly distinguish tasks of a longer duration from shorter tasks, even though the actual durations were not correct. A number of factors associated with the task per se appeared to influence agreement between self-reports and reference data, including type of task, true task duration, task pattern across time (continuous versus discontinuous), and whether the addressed task is composed of subtasks. The musculoskeletal health status of the respondent did not have a clear effect on the ability to correctly report task durations. Studies differed in key design characteristics and detail of information reported, which hampers a formal aggregation of results.

Conclusions

The correctness of self-reported task durations is, at the best, moderate at the individual level, and this may present a significant problem when using self-reports in task-based assessment of individual job exposures. However, average self-reports at the group level appear reasonably correct and may thus be a viable method in studies addressing, for instance, the relative occurrence of tasks in a production system. Due to the disparity of studies, definite conclusions on the quantitative effect on agreement of different modifiers are not justified, and we encourage future studies specifically devoted to understanding and controlling sources of bias in self-reported task durations. We also encourage studies developing decision support for when to apply or avoid self-reports to measure task durations, depending on study purpose and occupational setting.

Occupational Factors and Smoking Cessation among Unionized Building Trades Workers

The purpose of this study was to estimate the contribution of occupational factors to smoking cessation among building trades workers. Longitudinal data came from the MassBUILT smoking cessation intervention study for unionized building trades workers. Multivariable logistic regression analyses were applied to identify the significant predictors of smoking cessation, which was defined as abstinence from smoking during the previous 7 days at the 1-month monitoring and prolonged abstinence for at least 6 months at the 6-month monitoring. Greater concern about exposure to occupational hazards was significantly associated with increased likelihood of smoking cessation at 1 month (odds ratio = 1.06; 95% confidence interval = 1.01–1.11). Additionally, smokers who had a more positive view of their unions had at least marginally increased likelihood of smoking cessation at 1 month. Furthermore, older age, higher levels of educational attainment and household income, and fewer cigarettes smoked per day were important covariates that predicted smoking cessation. Concerns about exposures to work hazards should be incorporated into comprehensive intervention approaches for building trades workers. Additionally, the findings emphasize that blue-collar workers with lower income and education levels and heavy smokers should be considered target groups for implementing cessation interventions.

Cigarette smoking in building trades workers: the impact of work environment

BACKGROUND

Blue-collar workers smoke at higher rates than white-collar workers and the general population. Occupational factors may contribute to smoking behavior in this group. However, little is known about the role of occupational factors in explaining cigarette-smoking patterns.

METHODS

This study used cross-sectional data from the MassBUILT smoking cessation intervention study. Multivariable logistic regression analysis was conducted to investigate the association of occupational factors with current cigarette smoking among 1,817 building trades workers.

RESULTS

Current cigarette smoking was significantly associated with the following occupational factors: union commitment (OR = 1.06; 95% CI: 1.00-1.12); exposure to dust (OR = 1.50; 95% CI: 1.15-1.95), exposure to chemicals (OR = 1.41; 95% CI: 1.11-1.79); and concern about exposure to occupational hazards (OR = 0.93; 95% CI: 0.91-0.95).

CONCLUSION

The findings highlight the need to explicate the pathways by which occupational factors may contribute to current smoking behavior among building trades workers. Smoking cessation programs for this population should consider work-related occupational factors along with individual approaches.

Diversity of tasks and information technologies used by office workers at and away from work

BACKGROUND

Computer use is associated with musculoskeletal complaints among office workers. Insufficient exposure diversity between tasks is a proposed etiological factor, but little information exists on diversity of tasks and information and communication technologies (ICT) among office workers.

METHOD

Direct observation and self-report data were collected on tasks performed and ICT used among 24 office workers, over 12 h in work and non-work environments. Self-reports were repeated on four additional days.

RESULTS

Observations were for a mean [SD] 642[40] min. Productive tasks comprised 63% of observations, instrumental 17%, self-care 12% and leisure 8%. Non-ICT tasks comprised 44% of observations; New electronic-based ICT 36%; Old paper-based ICT 15%, and Combined ICT tasks 4%. Proportions of tasks and ICT use differed between environments and days.

CONCLUSION

Information about diversity in tasks and ICT provides the basis for future investigations into exposure variation in ICT-intensive environments and possible musculoskeletal health risks. STATEMENT OF RELEVANCE: Information and communication technologies (ICT) provide office workers access to perform work-related tasks after work hours and in away-from-work locations. Musculoskeletal disorder risk assessment for office workers should account for actual tasks performed over a work day, including away from work exposures. This study provides rich, detailed data on occurrence of tasks performed and ICT used by office workers throughout the day.

Decisional style, mood and work communication: email diaries

To understand the use of technology to support interpersonal interaction, a theory of decisional style was applied to email use within the workplace. Previous research has used self-report and rating scales to address employee email behaviours, but this falls short of management's capability to monitor the actual behaviour. Thirty-nine employed individuals completed a five-day communication diary recording their actual behaviour upon receiving personal and work-related emails as well as the Melbourne Decision Making Questionnaire and the Depression Anxiety Stress Scales. It was found that vigilant individuals were more likely to use email in an efficient manner by deleting personal email and being less likely to open email later. Procrastinators, buckpassers and people experiencing high levels of negative affect were all more likely to delay dealing with email, which could be viewed as dealing with email in a less efficient manner. STATEMENT OF RELEVANCE: This work offers insights as to how people receive and process emails and is thus relevant to the development and implementation of collaborative technologies. Whilst other studies use individual's self-reports, this study uses a more accurate communication diary. Decisional style can predict the monitoring and response to electronic communication.

Multivariate, longitudinal analysis of the impact of changes in office work environments on surface electromyography measures

PURPOSE

To detect impacts of changes in work environment and worker-equipment interface variables upon surface electromyography (EMG) measures using multivariate, longitudinal analysis.

METHODS

For 33 office workers, yearly measurements (1999-2001) were taken during normal work. Independent variables were related to work environment (expert-observed equipment dimensions, work organization on questionnaire) and interface (expert-observed postures, self-reported workstation-equipment relative fit i.e. inside or outside guidelines-informed location, and 30 min video-based task analysis). Internal mechanical exposure (EMG) was recorded bilaterally from extensor carpi radialis brevis (ECRB) and upper trapezius sites, each side, also for 30 min. Dependent variables were amplitude probability distribution functions (APDF 50 and 90%) and gaptime for entire record EMG (over all tasks) and task-specific EMG (for four separate tasks). Multivariate mixed models used independent variables to predict EMG measures (4 muscle sites × (1 entire record + 4 task specific) = 20 models total).

RESULTS

Among EMG measures, 9/16 means and 2/16 variances were significantly different across years (p < 0.1). Environment and interface variables explained part of the variation in EMG measures in 13/20 models. The most consistent predictors included: (1) increased monitor distance predicted reduced APDFs and increased gaptimes; (2) wrist extension <20° predicted decreases in left ECRB APDFs; (3) keyboard location within guidelines predicted improvements in all right ECRB EMG measures during keyboarding; and (4) longer task duration predicted higher APDFs and lower gaptimes.

CONCLUSION

Longitudinal analysis with multivariate models can detect the impacts of changes in environment and interface exposures on EMG measures among office workers.

Effects of passive computer use time and non-computer work time on the performance of electronic activity monitoring

This study aimed to examine the effects of passive and non-computer work time on the estimation of computer use times by electronic activity monitoring. A total of 20 subjects with computers were monitored for 3 h. Average relative error for total computer use time estimation was about 4%, given that non-computer work time was 20% of the 3-h monitored period. No significant impact of passive computer use time was found in this study. Non-computer work time of 40% or less is suggested as criteria for the application of electronic activity monitoring to ensure reliability in the physical work loading assessment. Statement of Relevance: This research studied the criteria of non-computer work time for the appropriate use of electronic activity monitoring to ensure reliability in the assessment of physical work loading. It is suggested that it should be set to 40% or less of the 3-h monitoring period.

In vivo laboratory validation of the physiometer: a measurement system for long-term recording of posture and movements in the workplace

Posture and movement are thought to be important risk factors for the development of work-related musculoskeletal disorders. Whole day occupational exposure assessment has typically used self-report or observation techniques, but the need for more accurate measurement is now recognised. The aim of this study was to compare the kinematic recordings of a frequently used field system (physiometer) with two laboratory-based systems (Fastrak and Peak) in vivo. Head, thorax and right arm kinematics were recorded simultaneously by the three systems whilst a subject performed 27 single and multiple plane physiological and simulated daily living task movement trials. Errors observed in the Fastrak and Peak data included gimbal lock and quadrant errors. Physiometer data errors included undervalues, overvalues and temporal errors of slow response and resonance. All three systems showed some cross-talk. Agreement between the physiometer and the other systems was generally high for physiological movements (R(2) > 0.8) and less for functional movements (R(2) > 0.5). STATEMENT OF RELEVANCE: The physiometer recording device can provide an indication of posture across time in the workplace; however, its accuracy is limited, particularly during functional movements. Further technology should be developed to unobtrusively capture accurate all day 3-D kinematics.