Does occupational forward bending of the back increase long-term sickness absence risk? A 4-year prospective register-based study using device-measured compositional data analysis

Occupational and leisure-time physical activity and prospective musculoskeletal pain-relief prescribed medication among blue-collar workers: 24-h device-measured physical activity and Danish registers

Musculoskeletal pain is the biggest contributor to burden of disease, causing excessive use of pain-relief medication. Non-pharmaceutical measures are called on for handling this burden. Guidelines recommend physical activity as an effective non-pharmaceutical measure. However, it is unknown if occupational physical activity has the same preventive effects on redeeming pain-relief medication as when performed during leisure-time ("The Physical Activity Paradox"). We aimed to investigate if the paradox contributes to the redemption of prescribed pain relief-medication. 24-h device-measured physical activity data [sitting, standing, light physical activity, moderate-to-vigorous physical activity (MVPA) and time in bed)] were collected from 824 workers using a thigh-worn accelerometer during work and leisure-time. Redeemed pain-relief prescribed medication was retrieved from the Danish National Prescription Registry during a 4-year follow-up. The prospective association between occupational and leisure-time physical activity and number of redeemed pain-relief prescribed medication was analyzed using a generalized linear model, adjusted for potential confounders. During follow-up, 53% of the workers redeemed a pain-relief medication. In leisure-time, 30 min more of MVPA per day were associated with 23% lower risk (RR = 0.77; 95% CI 0.64 - 0.94) of redeeming pain-relief medication. In contrast, occupational physical activity was not associated with the risk of redeeming pain-relief medication [RR = 1.04 (95% CI 0.89 - 1.20)]. Leisure-time MVPA was associated with lower risk of redeeming pain-relief medication, while no beneficial association was found for occupational MVPA. These findings support the paradox that the domain of physical activity is important for redeeming pain-relief medication. PERSPECTIVE: Leisure-time MVPA differs from occupational MVPA in its association with redeeming pain-relief medication. Increasing leisure-time MVPA may serve as an effective non-pharmacological strategy to reduce pain-relief medication redemption. These findings could potentially inform guidelines for managing musculoskeletal pain, highlighting the need to differentiate between occupational and leisure-time physical activity.

Occupational Physical Activity Among Pregnant Employees in the Danish Workforce: The PRECISE Occupational Cohort Profile

Purpose

Occupational physical activity (OPA) has been linked to adverse pregnancy outcomes, although findings are not consistent. This paper describes the PRECISE Occupational Cohort, designed with the purpose to obtain comprehensive information on OPA with objective measurements and prospective information on pregnancy-related discomforts and sick leave among pregnant employees in Denmark.

Methods

A total of 1556 pregnant participants were included between January 2023 and June 2024 from six obstetric departments in relation to the first trimester ultrasound scan. Information on OPA, pregnancy-related discomforts and sick leave was collected by repeated weekly questionnaires. Additionally, a subgroup of 327 pregnant participants and 90 non-pregnant co-workers were invited for repeated objective measurements, and/or workplace observations. A total of 603 accelerometer measurements from 412 unique participants, and 138 workplace observations were obtained from 102 unique participants. Time spent standing, walking and forward bending was acquired by accelerometers, and information on lifting and person-handlings was quantified by observations. All participants covered 197 occupational codes.

Results

A total of 1008 pregnant participants on average responded to the weekly questionnaires from pregnancy weeks 12-40. High frequencies of pregnancy discomforts were reported throughout pregnancy, and on average only 11% reported no discomforts. Pregnancy-related sick leave increased throughout pregnancy, peaking in pregnancy week 29, where 26% reported at least one day of pregnancy-related sick leave in the past week.

Conclusion

This cohort provides unique repeated measurements with comprehensive information about pregnant employees across many jobs, disclosing high levels of pregnancy discomforts and sick leave throughout pregnancy. The information will enable investigation of the associations of OPA, pregnancy-related discomforts and sick leave on a more detailed level than now. The objective measurements with novel information on OPA will contribute to the development of quantitative Job Exposure Matrices enabling investigation of the association between OPA and adverse pregnancy outcomes in larger populations, with the potential to strengthen preventive guidelines.

A fatigue failure framework for the assessment of highly variable low back loading using inertial motion capture - a case study

Workers in manufacturing settings experience highly variable musculoskeletal loading, which current risk assessment methods often fail to fully capture. This study evaluated a Fatigue Failure-Based framework for estimating continuous lumbar loading from variable occupational loads. Worker movements and postures were recorded using Inertial Motion Capture technologies, and L5/S1 joint loading history was estimated through inverse dynamics. Stress cycles were analysed using Rainflow analysis, adjusted with Goodman's method, and summed using Palmgren-Miner rule to estimate cumulative damage. The framework was tested in live industrial settings with eight automotive workers across 108 trials. Logistic regression models demonstrated significant correlations between cumulative damage estimates and self-reported low-back pain (OR = 2.16, 95% CI: 1.30, 3.57). This framework provides a novel method for analysing highly variable loading to estimate cumulative exposure in ergonomics, offering a starting point for future research and potential applications in assessing low back injury risks in similar occupational settings.

Reliability and Accuracy of Standard Reference Procedures for Measurements of Trunk and Arm Postures in Ergonomics

Adequate reference procedures for obtaining the reference zero-angle position are important for precise and accurate posture measurements, but few studies have systematically investigated these. A limited number of previous studies suggest differences in accuracy between procedures, with some causing an underestimation of the true arm elevation angle when sensors are taped to the skin. The reliability of commonly used reference procedures for the measurement of the trunk posture is also not well explored, and alternative procedures may improve precision. Based on this identified gap, this study evaluated the test-retest reliability of the N-position (I-pose), i.e., the standard procedure for recording trunk postures, and compared it with two new alternative procedures. Additionally, the accuracy of the N-position for measuring arm elevation angles was compared with one alternative procedure. A total of 40 participants (22 women and 18 men) aged 26-70 years performed the reference procedures in a laboratory setting. Postures were recorded using a smart workwear system equipped with two inertial measurement units (IMUs) embedded in pockets within the workwear. For the trunk posture, the N-position showed a slight lack of test-retest reliability, while one of the alternative procedures demonstrated better test-retest reliability. For the arm posture, the N-position, which does not include lateral trunk inclination, resulted in a substantial underestimation of the arm elevation angle of approximately 15°, which is a novel finding. In contrast, the posture involving trunk inclination closely matched the targeted reference, with a difference of less than 2°. This study underscores the importance of selecting appropriate reference procedures to ensure precise and accurate posture measurements.

Can home care work be organized to promote musculoskeletal health for workers? Results from the GoldiCare cluster randomized controlled trial

BACKGROUND

Workers in home care have high sick leave rates, predominantly because of musculoskeletal pain. The Goldilocks Work Principle proposes that health should be promoted by a "just right" composition of work tasks. Weekly workloads differ substantially between home care workers, suggesting that certain workers may have workloads that are too high, impacting their musculoskeletal health. The aim of this study was to evaluate the effectiveness of a "GoldiCare" intervention redistributing weekly workloads to become more equal among the homecare workers. Outcomes were pain in the neck/shoulder and lower back, and the implementation of the intervention was also evaluated.

METHODS

A 16-week cluster randomized controlled trial was conducted with 125 workers from 11 home care units, divided into six intervention units and five control units. The operation coordinators of each intervention unit were educated in the Goldilocks Work Principle and provided with a planning tool to facilitate an even distribution of high care need clients. The control group continued their usual work. Primary outcomes were pain intensity in the neck/shoulder and lower back (0 to 10). Secondary outcomes included fatigue (0 to 10), composition of physical behaviors and postures (accelerometers), adherence to the intervention (weekly usage rates of the planning tool), and performance of the intervention (percentage of workers with an even distribution of workload).

RESULTS

The analysis showed no difference between the intervention and control groups in change in lower back pain (0.07, 95%CI[-0.29;0.43]), neck/shoulder pain (-0.06, 95%CI[-0.49;0.36]) or fatigue (0.04, 95%CI[-0.52;0.61]. No significant changes were observed in the composition of physical behaviors (p = 0.067) or postures (p = 0.080-0.131) between the two groups. The intervention was succesfully implemented in three units of the six, with adherence ranging from 82-100% across the intervention period. The remaining three units had an adherence of 0-47%. No improvement in performance was observed.

CONCLUSION

No significant intervention effects were observed on musculoskeletal pain, fatigue, or the composition of physical behaviors and postures. The findings suggest that the intervention was not adequately implemented within the organization. Consequently, we cannot discern whether the lack of positive results were due to poor implementation or an ineffective intervention. Results thus highlight the need for a more comprehensive understanding of organizational structures within home care to facilitate more effective implementations. The hypothetical effectiveness of a fully implemented intervention remains unknown.

TRIAL REGISTRATION

Clinicaltrials.gov ID: NCT05487027, submitted: 03/08/2022.

The Use of Wearable Systems for Assessing Work-Related Risks Related to the Musculoskeletal System-A Systematic Review

Work-related musculoskeletal disorders (WRMSDs) are a leading cause of chronic conditions among working-age adults. Preventing these disorders is crucial to reducing their impact, and quantitative analysis through sensors can help identify their causes and guide ergonomic solutions. This systematic review aims to compile research from 2000 to 2023 published in English and sourced from Web of Science, Scopus, or PubMed that examines workers' movements during tasks using wearable sensor systems that are applicable in workplace settings. The goal is to identify the job sectors that have been studied and highlight tasks lacking ergonomic risk research. A total of 111 papers were selected through a screening process across three databases, assessed using the McMaster risk of bias tool. The studies span various job sectors and report on the use of different technologies for data collection and study population sizes. The review identifies existing research on WRMSD risks utilizing wearable systems in different job sectors, drawing attention to under-researched areas that warrant further study. It serves as a foundation for future research aimed at understanding the causes of WRMSDs and developing solutions supported by wearable technologies to mitigate these risks.

Effectiveness of Sensors-Based Augmented Feedback in Ergonomics to Reduce Adverse Biomechanical Exposure in Work-Related Manual Handling-A Rapid Review of the Evidence

Manual handling is a major risk factor for work-related musculoskeletal disorders and one of the leading causes of disability-adjusted life years globally, necessitating multifaceted risk reduction measures. One potential intervention for manual handling tasks is work technique training assisted by augmented feedback on biomechanical exposures. However, there is a research gap regarding its effectiveness specifically for manual handling tasks in both real work environments and controlled settings, as well as its ability to induce retained reductions in biomechanical exposure. The gap was investigated using a rapid review comprising a literature search using two databases and 11 reviews/overviews to identify studies from the past 20 years, up to studies published by 1 June 2024. Sixteen studies were identified, with 14 of them being of high or moderate methodological quality and were included. Three studies were conducted in real work environments and eleven in controlled settings. Most studies (n = 9) used auditory feedback, followed by vibration feedback (n = 6). In real work environments, the evidence for the effectiveness of sensor-based augmented feedback in reducing biomechanical exposure during administration was considered to be inconsistent and very limited directly after administration. For longer periods after administration, ranging from one week to more than six months, there is currently no evidence demonstrating the effectiveness of the feedback. In controlled settings, there was strong evidence for its effectiveness during and immediately after administration, and limited evidence for effectiveness up to six months post-administration when considering the tasks included in the training. Future research needs are discussed.

What have we learned about risk assessment and interventions to prevent work-related musculoskeletal disorders and support work participation?

OBJECTIVE

The Scandinavian Journal of Work, Environment & Health (SJWEH) was established half a century ago. This paper provides an overview of research on musculoskeletal disorders (MSD) published over these 50 years. Three themes are described: risk assessment, interventions to prevent work-related MSD, and interventions to support work participation. Finally, implications for future research are highlighted.

METHODS

A systematic literature search was performed for all papers on MSD published in SJWEH. Each paper was coded on several criteria including research topic, type of MSD, risk factor(s), and number of citations. Findings were tabulated, and discussions within the author team defined the main results and future research directions.

RESULTS

The search resulted in 1056 papers, of which 474 were included. The most reported-on MSD was low-back pain (LBP, 18%) and the most reported-on work-related risk factors were physically demanding work (14%) and psychosocial factors (12%). Research has contributed to improving case definitions, refining work-related exposure criteria, and recognizing the varying importance of physical and psychosocial factors across different MSD. Research on the association between work-related risk factors and LBP continues to emerge. Effective interventions for prevention of MSD are characterised by sufficient exposure reduction, while supporting work participation requires integrating health care, with multidisciplinary actions directed at factors involving the worker, employer, and workplace.

CONCLUSION

Research has provided valuable insights into risk assessment, interventions for preventing work-related MSD, and supporting work participation. Intervention studies remain warranted and new areas include adopting whole-system approaches to prevent work-related MSD and promoting the concept of musculoskeletal health.

A Rapid Review on the Effectiveness and Use of Wearable Biofeedback Motion Capture Systems in Ergonomics to Mitigate Adverse Postures and Movements of the Upper Body

Work-related diseases and disorders remain a significant global health concern, necessitating multifaceted measures for mitigation. One potential measure is work technique training utilizing augmented feedback through wearable motion capture systems. However, there exists a research gap regarding its current effectiveness in both real work environments and controlled settings, as well as its ability to reduce postural exposure and retention effects over short, medium, and long durations. A rapid review was conducted, utilizing two databases and three previous literature reviews to identify relevant studies published within the last twenty years, including recent literature up to the end of 2023. Sixteen studies met the inclusion criteria, of which 14 were of high or moderate quality. These studies were summarized descriptively, and the strength of evidence was assessed. Among the included studies, six were rated as high quality, while eight were considered moderate quality. Notably, the reporting of participation rates, blinding of assessors, and a-priori power calculations were infrequently performed. Four studies were conducted in real work environments, while ten were conducted in controlled settings. Vibration feedback was the most common feedback type utilized (n = 9), followed by auditory (n = 7) and visual feedback (n = 1). All studies employed corrective feedback initiated by the system. In controlled environments, evidence regarding the effectiveness of augmented feedback from wearable motion capture systems to reduce postural exposure ranged from strong evidence to no evidence, depending on the time elapsed after feedback administration. Conversely, for studies conducted in real work environments, the evidence ranged from very limited evidence to no evidence. Future reach needs are identified and discussed.

Is patients' activities of daily living self-care score in Norwegian home care a proxy for workers standing at work?

BACKGROUND

Prolonged standing at work may contribute to increased risk of musculoskeletal pain in home care workers. Patients' activities of daily living (ADL) score may be a proxy for home care workers' standing time at work. The objective of the present study was to investigate the association between patients' ADL self-care score, and workers standing time.

METHODS

This cross-sectional study measured time spent standing, sitting and in physical activity for seven days using thigh-worn accelerometers, among 14 home care workers. Patients' ADL self-care scores are routinely adjusted by home care nurses, and time intervals of home care visits are stored in home care services electronic patient journal. We collected ADL self-care scores and start and end time points of visits, and categorized ADL self-care scores as low (ADL ≤ 2.0), medium (ADL > 2.0 to 3.0) or high (ADL > 3.0). Physical behavior data were transformed to isometric log-ratios and a mixed-effect model was used to investigate differences in physical behavior between the three ADL self-care score categories.

RESULTS

We analyzed 931 patient visits and found that high ADL self-care scores were associated with longer standing times relative to sitting and physical activity, compared to low ADL score (0.457, p = 0.001). However, no significant differences in time spent standing were found between high and medium ADL patient visits (0.259, p = 0.260), nor medium and low (0.204, p = 0.288). High ADL score patients made up 33.4% of the total care time, despite only making up 7.8% of the number of patients.

CONCLUSION

Our findings suggest that caring for patients with high ADL self-care score requires workers to stand for longer durations and that this group of patients constitute a significant proportion of home care workers' total work time. The findings of this study can inform interventions to improve musculoskeletal health among home care workers by appropriate planning of patient visits.

The impact of leisure-time physical activity and occupational physical activity on sickness absence. A prospective study among people with physically demanding jobs

OBJECTIVES

This prospective study aimed to investigate the relation between occupational physical activity (OPA), leisure-time physical activity (LTPA) and sickness absence (SA). A second aim was to explore the possible interaction effects between OPA and LTPA in determining SA.

METHODS

The study is based on data from 304 workers in the service and manufacturing sector. Moderate-to-vigorous physical activity (MVPA) was measured by two Axivity AX3 accelerometers for 2-4 consecutive working days. Participants reported on the level of their physically demanding tasks by using a 5-item scale from the Job Content Questionnaire. Data on SA was provided by the administration departments of the participating companies during a 1 year follow-up period. We used negative binomial regression models for our statistical analysis.

RESULTS

After adjusting for potential confounders, physically demanding tasks were significantly associated with a higher number of SA episodes and days. Accelerometer-assessed MVPA during leisure time but not during work was correlated with lower SA. Our results show a significant interaction effect between MVPA during work and leisure time in the sense that more MVPA during work increased the risk for SA days only among workers with low LTPA, but not among workers with moderate-to-high LTPA.

CONCLUSIONS

Our results indicate that LTPA and OPA are related to opposite SA outcomes. MVPA during leisure time and work interact in their effect on SA, whereas we found no interaction effect between LTPA and self-reported physically demanding tasks in determining SA.

The association between reallocations of time and health using compositional data analysis: a systematic scoping review with an interactive data exploration interface

BACKGROUND

How time is allocated influences health. However, any increase in time allocated to one behaviour must be offset by a decrease in others. Recently, studies have used compositional data analysis (CoDA) to estimate the associations with health when reallocating time between different behaviours. The aim of this scoping review was to provide an overview of studies that have used CoDA to model how reallocating time between different time-use components is associated with health.

METHODS

A systematic search of four electronic databases (MEDLINE, Embase, Scopus, SPORTDiscus) was conducted in October 2022. Studies were eligible if they used CoDA to examine the associations of time reallocations and health. Reallocations were considered between movement behaviours (sedentary behaviour (SB), light physical activity (LPA), moderate-to-vigorous physical activity (MVPA)) or various activities of daily living (screen time, work, household chores etc.). The review considered all populations, including clinical populations, as well as all health-related outcomes.

RESULTS

One hundred and three studies were included. Adiposity was the most commonly studied health outcome (n = 41). Most studies (n = 75) reported reallocations amongst daily sleep, SB, LPA and MVPA. While other studies reported reallocations amongst sub-compositions of these (work MVPA vs. leisure MVPA), activity types determined by recall (screen time, household chores, passive transport etc.) or bouted behaviours (short vs. long bouts of SB). In general, when considering cross-sectional results, reallocating time to MVPA from any behaviour(s) was favourably associated with health and reallocating time away from MVPA to any behaviour(s) was unfavourably associated with health. Some beneficial associations were seen when reallocating time from SB to both LPA and sleep; however, the strength of the association was much lower than for any reallocations involving MVPA. However, there were many null findings. Notably, most of the longitudinal studies found no associations between reallocations of time and health. Some evidence also suggested the context of behaviours was important, with reallocations of leisure time toward MVPA having a stronger favourable association for health than reallocating work time towards MVPA.

CONCLUSIONS

Evidence suggests that reallocating time towards MVPA from any behaviour(s) has the strongest favourable association with health, and reallocating time away from MVPA toward any behaviour(s) has the strongest unfavourable association with health. Future studies should use longitudinal and experimental study designs, and for a wider range of outcomes.

Cost and statistical efficiency of posture assessment by inclinometry and observation, exemplified by paper mill work

Postures at work are paramount in ergonomics. They can be determined using observation and inclinometry in a variety of measurement scenarios that may differ both in costs associated with collecting and processing data, and in efficiency, i.e. the precision of the eventual outcome. The trade-off between cost and efficiency has rarely been addressed in research despite the obvious interest of obtaining precise data at low costs. Median trunk and upper arm inclination were determined for full shifts in 28 paper mill workers using both observation and inclinometry. Costs were estimated using comprehensive cost equations; and efficiency, i.e. the inverted standard deviation of the group mean, was assessed on basis of exposure variance components. Cost and efficiency were estimated in simulations of six sampling scenarios: two for inclinometry (sampling from one or three shifts) and four for observation (one or three observers rating one or three shifts). Each of the six scenarios was evaluated for 1 through 50 workers. Cost-efficiency relationships between the scenarios were intricate. As an example, inclinometry was always more cost-efficient than observation for trunk inclination, except for observation strategies involving only few workers; while for arm inclination, observation by three observers of one shift per worker outperformed inclinometry on three shifts up to a budget of €20000, after which inclinometry prevailed. At a budget of €10000, the best sampling scenario for arm inclination was 2.5 times more efficient than the worst. Arm inclination could be determined with better cost-efficiency than trunk inclination. Our study illustrates that the cost-efficiency of different posture measurement strategies can be assessed and compared using easily accessible diagrams. While the numeric examples in our study are specific to the investigated occupation, exposure variables, and sampling logistics, we believe that inclinometry will, in general, outperform observation. In any specific case, we recommend a thorough analysis, using the comparison procedure proposed in the present study, of feasible strategies for obtaining data, in order to arrive at an informed decision support.

The Effect of Corrective and Encouraging Accumulated Vibrotactile Feedback on Work Technique Training and Motivation-A Pilot Study

Encouraging feedback is shown to increase motivation and facilitate learning in different settings, though there is a lack of knowledge of applying it in work technique training. This pilot study aimed to evaluate two accumulated vibrotactile feedback strategies for work technique training using a smart workwear system. Eight women and two men participated in the study. They were divided into two groups, receiving the corrective feedback or the combined corrective and encouraging feedback while doing simulated manual handling tasks in a lab environment. Questionnaires and semi-structured interviews were used to evaluate the motivation, learning, and user experiences. In this small sample size, we saw that both groups significantly improved their work technique of upper arm and trunk postures, and no significant difference between groups was seen. In addition, both groups reported increased ergonomic awareness, were satisfied with the feedback training, and considered the system useful. However, the combined feedback group had slightly lower ratings of motivation and more negative experiences of the corrective feedback itself compared to the corrective feedback group. Both groups had positive experiences with the encouraging feedback. Future research should consider investigating the long-term learning effects of using solely corrective or encouraging accumulated feedback for work technique training with such systems.

Physical Work Demands of Maintenance Workers on Onshore Petroleum Facilities in Norway: An Observational Study Utilizing Wearable Sensor Technology

OBJECTIVES

High physical work demands can cause musculoskeletal disorders and sick leave in petroleum workers. However, our knowledge of their physical work demands is scarce and based on self-report. The objective of our study is to work towards closing this knowledge gap by assessing the physical work demands of onshore petroleum maintenance workers using body-worn sensors.

METHODS

A total of 46 of 69 eligible maintenance workers (37 mechanics and 9 process technicians) from three onshore petroleum facilities in Norway filled in a questionnaire and diary and wore five accelerometers and a heart rate sensor for up to six consecutive workdays. Work-related physical activity and postures were classified using rule-based modelling in a modified version of the validated Acti4 software.

RESULTS

The onshore maintenance petroleum workers were working an average of 10 h a day and spent on average this time with 48% (SD = 16.5) sitting, 1% (SD = 2.8) lying down, 39% (SD = 16.2) in light physical activity, and 9% (SD = 3.8) in moderate to vigorous physical activity. During work hours while at feet, we found arm elevation ≥60° to be 11% (SD = 7.1) (68 min), and forward bending of the trunk ≥60° to be 2% (SD = 2.2) (14 min). The workers spent 2% (SD = 2.5) (12 minu) of the workhours kneeling. We observed a high inter-individual variation for all these work exposures. Moreover, 26% (12) of the workers conducted static standing for >30% of the workday, and 17% (8) spent more than half of the work hours >33% of their estimated maximal cardiovascular capacity.

CONCLUSIONS

While onshore maintenance petroleum workers on average spend about half of the workday sitting or lying down, the remaining worktime is spent with a rather high duration of arm elevation and forward bending. Quite high fraction of the workers spends much of the workhours in static standing and kneeling. We see a substantial variation in these work exposures between the workers. The findings indicate a need for preventive measures in how work is organized and performed.

Does it matter for health if steps are taken during work or leisure? A prospective accelerometer study using register-based long-term sickness absence

BACKGROUND

Walking is known to be good for health. However, it is unknown whether it matters if steps are taken during work or leisure. Therefore, we aimed to examine the prospective association between accelerometer-measured steps taken during work or leisure and register-based long-term sickness absence (LTSA).

METHODS

We included 937 blue- and white-collar workers from the PODESA cohort who wore a thigh-based accelerometer over four days to measure number of steps during work and leisure. Steps were divided into domain based on diary data. First event of LTSA was retrieved from a national register with four years' follow-up. We used Cox proportional hazard models to analyze the association between domain-specific and total daily steps and LTSA, adjusted for age, sex, job type, smoking, and steps in the other domain (e.g., work/leisure).

RESULTS

We found more steps at work to be associated with a higher LTSA risk [Hazard Ratio (HR):1.04; 95% CI: 1.00-1.08 per 1000 steps]. No significant association was found between steps during leisure and LTSA (HR: 0.97; 95% CI: 0.91-1.02), nor between total daily steps and LTSA (HR: 1.01; CI 95% 0.99-1.04).

CONCLUSIONS

More steps at work were associated with higher risk of LTSA, while steps during leisure was not clearly associated with LTSA risk. These findings partly support 'the physical activity paradox' stating that the association between physical activity and health depends on the domain.

Wearable Motion Capture Devices for the Prevention of Work-Related Musculoskeletal Disorders in Ergonomics-An Overview of Current Applications, Challenges, and Future Opportunities

Work-related musculoskeletal disorders (WMSDs) are a major contributor to disability worldwide and substantial societal costs. The use of wearable motion capture instruments has a role in preventing WMSDs by contributing to improvements in exposure and risk assessment and potentially improved effectiveness in work technique training. Given the versatile potential for wearables, this article aims to provide an overview of their application related to the prevention of WMSDs of the trunk and upper limbs and discusses challenges for the technology to support prevention measures and future opportunities, including future research needs. The relevant literature was identified from a screening of recent systematic literature reviews and overviews, and more recent studies were identified by a literature search using the Web of Science platform. Wearable technology enables continuous measurements of multiple body segments of superior accuracy and precision compared to observational tools. The technology also enables real-time visualization of exposures, automatic analyses, and real-time feedback to the user. While miniaturization and improved usability and wearability can expand the use also to more occupational settings and increase use among occupational safety and health practitioners, several fundamental challenges remain to be resolved. The future opportunities of increased usage of wearable motion capture devices for the prevention of work-related musculoskeletal disorders may require more international collaborations for creating common standards for measurements, analyses, and exposure metrics, which can be related to epidemiologically based risk categories for work-related musculoskeletal disorders.

Evaluation of In-Cloth versus On-Skin Sensors for Measuring Trunk and Upper Arm Postures and Movements

Smart workwear systems with embedded inertial measurement unit sensors are developed for convenient ergonomic risk assessment of occupational activities. However, its measurement accuracy can be affected by potential cloth artifacts, which have not been previously assessed. Therefore, it is crucial to evaluate the accuracy of sensors placed in the workwear systems for research and practice purposes. This study aimed to compare in-cloth and on-skin sensors for assessing upper arms and trunk postures and movements, with the on-skin sensors as the reference. Five simulated work tasks were performed by twelve subjects (seven women and five men). Results showed that the mean (±SD) absolute cloth-skin sensor differences of the median dominant arm elevation angle ranged between 1.2° (±1.4) and 4.1° (±3.5). For the median trunk flexion angle, the mean absolute cloth-skin sensor differences ranged between 2.7° (±1.7) and 3.7° (±3.9). Larger errors were observed for the 90th and 95th percentiles of inclination angles and inclination velocities. The performance depended on the tasks and was affected by individual factors, such as the fit of the clothes. Potential error compensation algorithms need to be investigated in future work. In conclusion, in-cloth sensors showed acceptable accuracy for measuring upper arm and trunk postures and movements on a group level. Considering the balance of accuracy, comfort, and usability, such a system can potentially be a practical tool for ergonomic assessment for researchers and practitioners.

Can home care work be organized to promote musculoskeletal health for workers? Study protocol for the Norwegian GoldiCare cluster randomized controlled trial

BACKGROUND

Home care workers perform physically strenuous tasks, in particular when handling patients with high care demands. Thus, musculoskeletal pain and sick leave is greater in this group than in the general population. To ease these issues, we will implement a Goldilocks Work intervention (GoldiCare), redistributing schedules between workers to achieve a "just right" weekly structure of physical work that can promote health. This protocol paper describes the content, design, implementation and evaluation of the cluster randomized controlled trial of the GoldiCare intervention in home care.

METHODS

The cluster randomized controlled trial is a 16-week workplace organizational intervention implemented through operations managers at the home care units. The operations managers will be introduced to the Goldilocks Work Principle and a GoldiCare tool, to assist the operations managers when composing a "just right" distribution of work schedules throughout the week. The GoldiCare tool provides an overview of the physical strain for each shift, based on the number of patients and their need for care. We expect to include 11 units, which will be randomized to either intervention or control at a 1:1 ratio. Home care workers assigned to the control group will continue to work as normal during the intervention period. Musculoskeletal pain in neck/shoulder and lower back will be the primary outcomes and we will also evaluate the composition of physical behaviors as well as fatigue after work as secondary outcomes. We will collect data using (1) daily questions regarding musculoskeletal pain and fatigue after work, (2) 7 days of objective measurements of physical behavior, (3) questionnaires about the participant's characteristics, health, and workplace psychosocial stressors and (4) information on the implementation of the GoldiCare tool. In addition, a process evaluation will be conducted using focus group discussions and individual interviews.

DISCUSSION

Due to the increasing aging population in need of care, measures that can improve the health of home care workers are paramount for the sustainability of this sector. This organizational intervention is based on information available nation-wide, and therefore has the potential to be scaled to all municipalities in Norway if proven effective.

TRIAL REGISTRATION

This clinical trial was registered on 08/05/2022 under NCT05487027 .